compass® for ppc/rpm

molbox1™
molbloc® Terminal
(Ver. 5.20 and Higher)
Operation and Maintenance Manual
© 1995 - 2007 DH Instruments, a Fluke Company
High pressure liquids and gases are potentially hazardous. Energy stored in these liquids and gases
can be released unexpectedly and with extreme force. High pressure systems should be assembled and
operated only by personnel who have been instructed in proper safety practices.
© 2007 DH Instruments, a Fluke Company All rights reserved.
Information in this document is subject to change without notice. No part of this document may be reproduced or transmitted in any
form or by any means, electronic or mechanical, for any purpose, without the express written permission of DH Instruments, a
Fluke Company 4765 East Beautiful Lane Phoenix AZ 85044-5318 USA.
DH Instruments makes sincere efforts to ensure accuracy and quality of its’ published materials; however, no warranty, expressed
or implied, is provided. DH Instruments disclaims any responsibility or liability for any direct or indirect damages resulting from the
use of the information in this manual or products described in it. Mention of any product does not constitute an endorsement by DH
Instruments of that product. This manual was originally composed in English and was subsequently translated into other
languages. The fidelity of the translation cannot be guaranteed. In case of conflict between the English version and other language
versions, the English version predominates.
DH Instruments, DH, DHI, molbox1, molbloc, molbloc-L, molbloc-S, molstic, COMPASS, CalTool are trademarks, registered and
otherwise, of DH Instruments, a Fluke Company.
VCR is a registered trademark of the Swagelok Company.
Viton is a registered trademarks of DuPont deNemours Company.
Windows is a registered trademark of Microsoft Corporation.
Document No. 550089n
050202
Printed in the USA.
© 1995 - 2007 DH Instruments, a Fluke Company
TABLE OF CONTENTS
TABLE OF CONTENTS
TABLE OF CONTENTS ...............................................................I
TABLES .................................................................................. V
FIGURES............................................................................... VII
ABOUT THIS MANUAL ............................................................. IX
1.
INTRODUCTION ................................................................. 1
1.1
PRODUCT OVERVIEW ...........................................................................................................................1
1.1.1
1.1.1.1
1.1.1.2
1.2
SPECIFICATIONS ...................................................................................................................................2
1.2.1
1.2.2
1.2.3
1.2.4
1.2.5
1.2.5.1
1.2.5.2
1.2.6
1.2.6.1
1.2.6.2
2.
MOLBLOC FLOW ELEMENTS .....................................................................................................................1
MOLBLOC-L FLOW ELEMENT .................................................................................................................1
MOLBLOC-S FLOW ELEMENT.................................................................................................................2
GENERAL SPECIFICATIONS.......................................................................................................................2
REFERENCE PRESSURE TRANSDUCER (RPT) SPECIFICATIONS ........................................................3
TEMPERATURE MEASUREMENT SPECIFICATIONS................................................................................3
MFC CONTROL FUNCTION (OPTIONAL) SPECIFICATIONS ....................................................................3
FLOW MEASUREMENT SPECIFICATIONS ................................................................................................4
MOLBLOC-L...............................................................................................................................................4
MOLBLOC-S ..............................................................................................................................................8
FRONT AND REAR PANELS......................................................................................................................17
FRONT PANEL ........................................................................................................................................17
REAR PANEL...........................................................................................................................................17
INSTALLATION ................................................................ 18
2.1
UNPACKING AND INSPECTION ..........................................................................................................19
2.1.1
2.1.2
2.2
2.3
SITE REQUIREMENTS..........................................................................................................................20
INITIAL SETUP......................................................................................................................................21
2.3.1
2.3.2
2.3.3
2.3.4
2.3.5
2.3.6
2.3.7
2.4
PREPARING FOR OPERATION .................................................................................................................21
POWER CONNECTION...............................................................................................................................21
MOLBOX1 TO MOLBLOC CONNECTIONS ...............................................................................................21
GAS SUPPLY AND FLOWPATH CONNECTIONS ....................................................................................21
VACUUM SUPPLY (MOLBLOC-S ONLY) ..................................................................................................22
COMMUNICATIONS CONNECTIONS ........................................................................................................23
MFC CONTROL OPTION CONNECTION ...................................................................................................23
POWER UP AND VERIFICATION.........................................................................................................23
2.4.1
2.4.2
2.4.3
2.4.4
2.4.5
2.4.6
2.5
2.6
REMOVING FROM PACKAGING ...............................................................................................................19
INSPECTING CONTENTS...........................................................................................................................19
POWER UP ..................................................................................................................................................23
CHECK PROPER PRESSURE MEASUREMENT OPERATION ................................................................24
CHECK PROPER TEMPERATURE MEASUREMENT OPERATION ........................................................24
CHECK THE MFC CONTROL FUNCTION (OPTIONAL) ...........................................................................24
LEAK CHECK ..............................................................................................................................................24
CHECK/SET SECURITY LEVEL .................................................................................................................25
ADDITIONAL PRECAUTIONS TO TAKE BEFORE MAKING FLOW MEASUREMENTS ...................25
SHORT TERM STORAGE .....................................................................................................................25
Page I
© 1995 - 2007 DH Instruments, a Fluke Company
MOLBOX1™ OPERATION AND MAINTENANCE MANUAL
3.
OPERATION ..................................................................... 27
3.1
GENERAL OPERATING PRINCIPLES .................................................................................................27
3.1.1
3.1.2
3.1.3
3.1.3.1
3.1.3.2
3.1.4
3.1.5
3.2
MAIN RUN SCREEN .............................................................................................................................30
3.2.1
3.2.2
3.3
KEYPAD LAYOUT AND PROTOCOL ........................................................................................................33
DIRECT FUNCTION KEYS SUMMARY ......................................................................................................34
DIRECT FUNCTION KEYS....................................................................................................................35
3.4.1
3.4.2
3.4.2.1
3.4.2.2
3.4.3
3.4.3.1
3.4.3.2
3.4.3.3
3.4.3.4
3.4.3.5
3.4.4
3.4.4.1
3.4.4.2
3.4.4.3
3.4.4.4
3.4.4.5
3.4.5
3.4.5.1
3.4.5.2
3.4.6
3.4.6.1
3.4.6.2
3.4.6.3
3.4.6.4
3.4.6.5
3.4.6.6
3.4.6.7
3.4.6.8
3.4.7
3.4.8
3.4.8.1
3.4.8.2
3.4.8.3
3.4.9
3.5
MOLBLOC-L OPERATION .........................................................................................................................30
MOLBLOC-S OPERATION .........................................................................................................................31
MANUAL OPERATION..........................................................................................................................33
3.3.1
3.3.2
3.4
MOLBLOC CHANNEL A & CHANNEL B ...................................................................................................27
MOLBLOC-L AND MOLBLOC-S OPERATION ..........................................................................................27
FLOW READY/NOT READY INDICATION .................................................................................................28
MOLBLOC-L OPERATION ......................................................................................................................28
MOLBLOC-S OPERATION ......................................................................................................................28
REFERENCE PRESSURE TRANSDUCER (RPT) OVERPRESSURE.......................................................29
MOLBLOC-S BPR LIMITS ..........................................................................................................................29
[K].................................................................................................................................................................35
[GAS] ...........................................................................................................................................................36
MOLBLOC-L OPERATION ......................................................................................................................37
MOLBLOC-S OPERATION ......................................................................................................................38
[UNIT]...........................................................................................................................................................40
MASS FLOW VS. VOLUME FLOW .........................................................................................................41
VOLUMETRICALLY BASED MASS FLOW UNITS .................................................................................42
VOLUMETRICALLY BASED MASS FLOW UNITS AT VARIOUS REFERENCE
TEMPERATURES (UXXX).......................................................................................................................43
VOLUME FLOW UNITS (VLM) ................................................................................................................43
CUSTOMIZING FLOW UNITS AVAILABLE UNDER THE UNIT FUNCTION..........................................44
[TARE] .........................................................................................................................................................45
<1TARE>..................................................................................................................................................46
<2PURGE> ..............................................................................................................................................50
<3LEAK CHECK> ....................................................................................................................................52
<4AUTOZ> ...............................................................................................................................................59
<5BPR> (MOLBLOC-S OPERATION ONLY) ..........................................................................................64
[P&T] (PRESSURE AND TEMPERATURE) ...............................................................................................65
MOLBLOC-L OPERATION ......................................................................................................................66
MOLBLOC-S OPERATION ......................................................................................................................66
[DISPLAY]....................................................................................................................................................67
<1RATE>..................................................................................................................................................68
<2AVG> (AVERAGE)...............................................................................................................................69
<3 HI/LO> .................................................................................................................................................70
<4TOTAL> (TOTALIZER) ........................................................................................................................71
<5UNIT> ...................................................................................................................................................73
<6DEVIATION> ........................................................................................................................................73
<7FREEZE> .............................................................................................................................................75
<8CLEAN> ...............................................................................................................................................76
[A/B] .............................................................................................................................................................77
[MFC](OPTIONAL) ......................................................................................................................................77
MFC RUN SCREENS ..............................................................................................................................78
MFC PROFILES .......................................................................................................................................79
UNITS OF MEASURE WHEN USING THE MFC CONTROL OPTION ...................................................79
[RES]............................................................................................................................................................80
[SETUP] .................................................................................................................................................81
3.5.1
3.5.1.1
3.5.2
3.5.3
3.5.4
3.5.4.1
3.5.4.2
3.5.4.3
3.5.5
3.5.6
3.5.7
3.5.8
3.5.9
<1MOLBLOC> .............................................................................................................................................81
MOLBLOC-L AND MOLBLOC-S SIZE AND RANGE DESIGNATIONS ..................................................82
<2STAB>......................................................................................................................................................83
<3ADJ> ........................................................................................................................................................84
<4A_B> ........................................................................................................................................................85
GENERAL OPERATION (ASPECTS COMMON TO BOTH A_B MODES) .............................................85
A+B MODE...............................................................................................................................................86
A/B MODE ................................................................................................................................................87
<5MFC>........................................................................................................................................................88
<6REG>........................................................................................................................................................90
<7FLOWU> ..................................................................................................................................................91
<8PRESU> ...................................................................................................................................................91
<9TEMPU>...................................................................................................................................................91
© 1995 - 2007 DH Instruments, a Fluke Company
Page II
TABLE OF CONTENTS
3.6
[SPECIAL] .............................................................................................................................................92
3.6.1
3.6.1.1
3.6.1.2
3.6.1.3
3.6.1.4
3.6.1.5
3.6.2
3.6.2.1
3.6.3
3.6.3.1
3.6.4
3.6.5
3.6.5.1
3.6.5.2
3.6.5.3
3.6.6
3.6.6.1
3.6.6.2
3.6.6.3
3.6.7
3.6.8
3.6.9
4.
REMOTE OPERATION ......................................................109
4.1
4.2
OVERVIEW ..........................................................................................................................................109
INTERFACING.....................................................................................................................................109
4.2.1
4.2.1.1
4.2.1.2
4.2.2
4.3
4.4
RS232 INTERFACE ...................................................................................................................................110
COM1 .....................................................................................................................................................110
COM2 .....................................................................................................................................................110
IEEE-488 (GPIB) ........................................................................................................................................111
COMMANDS........................................................................................................................................112
4.3.1
4.3.2
4.3.3
4.3.4
4.3.4.1
4.3.4.2
COMMAND SYNTAX.................................................................................................................................112
COMMAND SUMMARY.............................................................................................................................112
ERROR MESSAGES .................................................................................................................................113
COMMAND DESCRIPTIONS ....................................................................................................................114
IEEE STD. 488.2 COMMON AND STATUS COMMANDS ....................................................................114
MOLBOX1 COMMANDS........................................................................................................................117
STATUS SYSTEM ...............................................................................................................................134
4.4.1
4.4.1.1
4.4.1.2
5.
<1RESET> ...................................................................................................................................................93
<1SETS> ..................................................................................................................................................93
<2UNITS> ................................................................................................................................................94
<3MFC> ...................................................................................................................................................94
<4CAL> ....................................................................................................................................................94
<5ALL> .....................................................................................................................................................95
<2LEVEL>....................................................................................................................................................95
SECURITY LEVELS.................................................................................................................................96
<3UL>...........................................................................................................................................................99
UPPER LIMIT ALARM AND SEQUENCE..............................................................................................100
<4CAL> ......................................................................................................................................................100
<5PREFS> .................................................................................................................................................100
<1SCRSVR> ..........................................................................................................................................101
<3ID>......................................................................................................................................................101
<3TIME>.................................................................................................................................................102
<6REMOTE> ..............................................................................................................................................102
COM1 AND COM2 .................................................................................................................................103
IEEE-488 ................................................................................................................................................103
RS232 SELF-TEST ................................................................................................................................103
<7DRIVERS> .............................................................................................................................................104
<8HEAD> ...................................................................................................................................................104
<9BPR>......................................................................................................................................................106
STATUS REPORTING SYSTEM ...............................................................................................................134
STATUS BYTE REGISTER ...................................................................................................................134
STANDARD EVENT REGISTER ...........................................................................................................136
MAINTENANCE, ADJUSTMENTS AND CALIBRATION ...........137
5.1
5.2
PRODUCT OVERVIEW ....................................................................................................................... 137
CALIBRATION OF REFERENCE PRESSURE TRANSDUCERS (RPTS)..........................................138
5.2.1
5.2.1.1
5.2.2
5.2.3
5.2.4
5.2.4.1
5.2.4.2
5.2.5
5.3
5.4
5.5
5.6
5.7
PRINCIPLE ................................................................................................................................................138
PA AND PM COEFFICIENTS ................................................................................................................138
EQUIPMENT REQUIRED ..........................................................................................................................139
SET-UP AND PREPARATION ..................................................................................................................139
VIEWING AND EDITING RPT READINGS AND CALIBRATION INFORMATION ..................................140
VIEWING RPT OUTPUTS .....................................................................................................................140
VIEWING AND EDITING RPT PA, PM AND CALIBRATION DATE ......................................................141
RPT CALIBRATION/ADJUSTMENT PROCEDURE WITHOUT USING CALTOOL FOR RPTS
SOFTWARE ...............................................................................................................................................142
MFC CONTROL FUNCTION ADJUSTMENT ......................................................................................144
OHMIC MEASUREMENT SYSTEM VERIFICATION ..........................................................................145
RELOADING EMBEDDED SOFTWARE INTO MOLBOX1 FLASH MEMORY................................... 147
RELOADING MOLBLOC EEPROM FILE............................................................................................147
OVERHAUL .........................................................................................................................................148
Page III
© 1995 - 2007 DH Instruments, a Fluke Company
MOLBOX1™ OPERATION AND MAINTENANCE MANUAL
6.
TROUBLESHOOTING .......................................................149
6.1
7.
OVERVIEW ..........................................................................................................................................149
APPENDIX ......................................................................155
7.1
CONVERSION OF NUMERICAL VALUES .........................................................................................155
7.1.1
7.1.2
7.1.3
7.2
7.3
VALVE DRIVERS ................................................................................................................................158
MFC CONTROL FUNCTION ............................................................................................................... 160
7.3.1
7.3.1.1
7.3.1.2
7.4
8.
PRESSURE................................................................................................................................................155
TEMPERATURE ........................................................................................................................................155
FLOW .........................................................................................................................................................156
MFC CONNECTOR....................................................................................................................................160
DETAILED SIGNAL DESCRIPTIONS....................................................................................................161
POPULAR CONFIGURATIONS.............................................................................................................161
WARRANTY STATEMENT..................................................................................................................163
GLOSSARY .....................................................................165
© 1995 - 2007 DH Instruments, a Fluke Company
Page IV
TABLES & FIGURES
TABLES
Table 1. molbloc-L Pressure Dependent Calibration Types ........................................................................ 5
Table 2. molbloc-L Ranges with Low Pressure Calibrations ....................................................................... 6
Table 3. molbloc-L Ranges with High Pressure Calibrations....................................................................... 7
Table 4: N2. molbloc-S Flow in nitrogen at Various molbloc Upstream Pressures ..................................... 9
Table 5: He. molbloc-S Flow in helium at Various molbloc Upstream Pressures...................................... 10
Table 6: Ar. molbloc-S Flow in argon at Various molbloc Upstream Pressures ........................................ 10
Table 7: H2. molbloc-S Flow in hydrogen at Various molbloc Upstream Pressures ................................. 11
Table 8: O2. molbloc-S Flow in oxygen at Various molbloc Upstream Pressures .................................... 11
Table 9: CH4. molbloc-S Flow in methane at Various molbloc Upstream Pressures................................ 12
Table 10: CO. molbloc-S Flow in carbon monoxide at Various molbloc Upstream Pressures.................. 12
Table 11: Air. molbloc-S Flow in air at Various molbloc Upstream Pressures .......................................... 13
Table 12: N2O. molbloc-S Flow in nitrous oxide at Various molbloc Upstream Pressures....................... 13
Table 13: SF6. molbloc-S Flow in sulfur hexafluoride at Various molbloc Upstream Pressures............... 14
Table 14: CO2. molbloc-S Flow in carbon dioxide at Various molbloc Upstream Pressures.................... 14
Table 15. molbloc-S Calibration Types ...................................................................................................... 15
Table 16. molbox1 Parts List ..................................................................................................................... 19
Table 17: Minimum molbloc-S Critical Flow (slm) in nitrogen at Various molbloc-S
Downstream Pressures ........................................................................................................... 30
Table 18. Summary of molbox1 Direct Function Key Operations.............................................................. 34
Table 19. Available molbloc-L Gases ........................................................................................................ 37
Table 20. Available molbloc-S Gases ........................................................................................................ 38
Table 21. Available Flow Units................................................................................................................... 45
Table 22. Flow Units and Corresponding Total Mass or Volume Units ..................................................... 72
Table 23. molbloc-L Size and Nominal Range Designations..................................................................... 82
Table 24. molbloc-S Size and Pressure to Flow Conversion Ratio (KF) ................................................... 83
Table 25. Pressure Units of Measure Available......................................................................................... 91
Table 26. Security Levels - Functions NOT Executed Per Function/Level................................................ 97
Table 27. COM1 and COM2 Available Settings....................................................................................... 103
Table 28. COM1 DB-9F Pin Designation ................................................................................................. 110
Table 29. COM2 DB-9M Pin Designation ................................................................................................ 111
Table 30. Command Summary ................................................................................................................ 112
Table 31. Error Messages........................................................................................................................ 113
Table 32. Status Byte Register ................................................................................................................ 134
Table 33. Standard Event Register.......................................................................................................... 136
Table 34. Troubleshooting Checklist........................................................................................................ 149
Table 35. Pressure Unit Conversions ...................................................................................................... 155
Table 36. Temperature Unit Conversion.................................................................................................. 155
Table 37. Conversions from kg/s to sccm at 0 °C for Various Gases...................................................... 156
Table 38. Conversions from sccm at 0 °C to Other Volumetrically Based Flow Units ........................... 156
Table 39. Conversions from Volumetrically Based Flow Units at 0 °C to Corresponding Units
at Another Temperature (uxxx).............................................................................................. 157
Page V
© 1995 - 2007 DH Instruments, a Fluke Company
MOLBOX1™ OPERATION AND MAINTENANCE MANUAL
Table 40. Conversions from kg/s to mole/s for Various Gases................................................................ 157
Table 41. Conversion from mole/s to pccm ............................................................................................. 157
Table 42. Conversion from sccm at 0 °C to Volume Flow Units at Another Pressure
and Temperature ................................................................................................................... 158
Table 43. Driver/Max Current Per Output ................................................................................................ 158
Table 44. External Drivers........................................................................................................................ 159
Table 45. Interface Cable Building Instructions ....................................................................................... 160
Table 46. Common MFC Connector Pin Out ........................................................................................... 162
Table 47. Brooks MFC Connector Pin Out .............................................................................................. 162
Table 48. DHI Authorized Service Providers ........................................................................................... 163
© 1995 - 2007 DH Instruments, a Fluke Company
Page VI
TABLES & FIGURES
FIGURES
Figure 1. Front Panel .................................................................................................................................. 17
Figure 2. Rear Panel .................................................................................................................................. 17
Figure 3. molbox1 Internal Pneumatic Schematic - CHANNEL A ACTIVE, molbloc-L OPERATION ...... 27
Figure 4. Keypad Layout ............................................................................................................................ 33
Figure 5. molbox1 Internal Pneumatic Schematic – TARING CHANNEL A, UPSTREAM molbloc-L
OPERATION............................................................................................................................ 47
Figure 6. molbox1 Internal Pneumatic Schematic – TARING CHANNEL A, molbloc-S OPERATION .... 50
Figure 7. molbox1 Internal Pneumatic Schematic – PURGING CHANNEL A........................................... 51
Figure 8. molbox1 Internal Pneumatic Schematic - LEAK CHECK molbox CHANNEL A......................... 54
Figure 9. molbox1 Internal Pneumatic Schematic - SYSTEM LEAK CHECK - CHECKING OFFSET
AND STABILITY ...................................................................................................................... 55
Figure 10. molbox1 Internal Pneumatic Schematic - SYSTEM LEAK CHECK ON CHANNEL A CHECKING OFFSET AND STABILITY................................................................................... 58
Figure 11. molbox1 Internal Pneumatic Schematic – molbloc-S OPERATION, CHANNEL A,
BPR ON ................................................................................................................................. 106
Figure 12. molbox1 Internal Pneumatic Schematic – molbloc-S OPERATION, CHANNEL A,
BPR OFF ............................................................................................................................... 107
Figure 13. Status Byte Register ............................................................................................................... 135
Figure 14. molbox1 Internal Pneumatic Schematic - RUN UPSTREAM OR DOWNSTREAM
ABSOLUTE RPT CALIBRATION .......................................................................................... 141
Figure 15. Cable Driver Ports................................................................................................................... 159
Page VII
© 1995 - 2007 DH Instruments, a Fluke Company
MOLBOX1™ OPERATION AND MAINTENANCE MANUAL
NOTES
© 1995 - 2007 DH Instruments, a Fluke Company
Page VIII
ABOUT THIS MANUAL
ABOUT THIS MANUAL
This manual provides the user with the information necessary to operate a molbox1 molbloc terminal with
molbloc mass flow elements to make mass flow measurements. It also includes a great deal of additional
information provided to help you optimize use of a molbloc/molbox1 system and take full advantage of its
many features and functions.
Before using the manual, take a moment to familiarize yourself with the Table of Contents structure.
All first time molbox1 users should read Section 1. Section 3.1 provides a comprehensive description of
general molbox1 operating principles. Section 4. is for remote operation from an external computer.
Section 1 provides maintenance and calibration information. Section 6 is a quick troubleshooting guide.
Use this section to troubleshoot unexpected molbox1 behavior based on the symptoms of that behavior.
Cross references are used extensively to direct you towards additional information on a topic.
Cross references are generally in parentheses and give the reference’s section number. For example:
(see Section 11).
Certain words and expressions have specific meaning as they pertain to molbox1. The Glossary Section
is useful as a quick reference for exact definition of specific words and expressions as they are used in
this manual.
FOR THOSE OF YOU WHO “DON’T READ MANUALS”, GO DIRECTLY TO SECTION 2.3, INITIAL SETUP, TO
SET UP YOUR molbox1. THEN GO TO SECTION 2.4, POWER UP AND VERIFICATION. THIS WILL GET YOU
RUNNING QUICKLY WITH MINIMAL RISK OF CAUSING DAMAGE TO YOURSELF OR YOUR molbox1.
THEN… WHEN YOU HAVE QUESTIONS OR START TO WONDER ABOUT ALL THE GREAT FEATURES
YOU MIGHT BE MISSING, GET INTO THE MANUAL!
Manual Conventions
(CAUTION) is used throughout the manual to identify user warnings and cautions.
(NOTE) is used throughout the manual to identify operating and applications advice and additional
explanations.
[ ] Indicates direct function keys (e.g., [RANGE]).
< > Indicates molbox1 screen displays (e.g., <1yes>).
Page IX
© 1995 - 2007 DH Instruments, a Fluke Company
MOLBOX1™ OPERATION AND MAINTENANCE MANUAL
NOTES
© 1995 - 2007 DH Instruments, a Fluke Company
Page X
1. INTRODUCTION
1.
INTRODUCTION
1.1
PRODUCT OVERVIEW
molbox1 is a support unit for making gas flow measurements using molbloc mass flow elements.
molbox1 reads calibration data off the molbloc EEPROM and measures molbloc upstream and
downstream pressure using built-in high precision Reference Pressure Transducers (RPTs). There are
two models with different ranges of pressure transducers (A350K, A700K).
An ohmic measurement system reads the resistance of the molbloc platinum resistance thermometers
from which molbloc temperature is calculated. Using the molbloc calibration data, measured pressures
and temperature and gas properties stored in memory, the flow rate of the gas flowing through the
molbloc is calculated.
Internal molbox1 valves support on-board PRESSURE TRANSDUCER TARING, molbloc-S BPR MODES,
LEAK TESTING and SELF PROTECTION functions as well as a GAS PURGE routine.
molbox1 provides a local user interface via a front panel key pad and display and includes advanced
on-board functions. Remote communication capability is supported with RS232 and IEEE-488 interfaces.
molbox1 is equipped to handle molblocs on two separate channels. This allows easy switching between
two different molblocs as well as certain special dual channel functions. Internal valving switches the
molbox1 pressure transducers from one molbloc to the other as needed.
molbox1 is intended for applications in which minimizing measurement uncertainty is the most important
requirement and/or integrated control of mass flow controllers (MFCs) is needed. A second model,
molbox RFM, is available for applications where a compact presentation and lower cost are the most
dominant requirements.
1.1.1
MOLBLOC FLOW ELEMENTS
Two different types of molblocs may be used with molbox1; molbloc-L (laminar) and
molbloc-S (sonic).
1.1.1.1
MOLBLOC-L FLOW ELEMENT
molbloc-L is the original molbloc laminar flow element. molbloc-L covers the
lower portion of the molbloc/molbox1 system flow range. The key molbloc-L
measurement is the differential pressure across the element, which is roughly
proportional to the mass flow rate through it. molbloc-L elements are calibrated
to be used at an absolute pressure which remains nearly constant, while the
differential pressure varies with flow rate. Different operating pressure options
and their effect on molbloc flow range are described in Section 1.2.5.1.1.
Page 1
© 1995 - 2007 DH Instruments, a Fluke Company
MOLBOX1™ OPERATION AND MAINTENANCE MANUAL
1.1.1.2
MOLBLOC-S FLOW ELEMENT
molbloc-S elements use critical (sonic) flow venturi nozzle technology to measure
flows which overlap with the ranges of molbloc-L and cover the higher end of the
molbloc/molbox1 system flow range. The mass flow rate through a molbloc-S
element is roughly proportional to the upstream absolute pressure when the flow
is “choked”, so the molbloc-S operating pressure can vary widely as the mass
flow rate is changed throughout the flow range. The limits of molbloc-S operating
pressure and flow ranges are defined by the molbloc-S calibration type,
described in Section 1.2.5.2.2.
1.2
SPECIFICATIONS
1.2.1
GENERAL SPECIFICATIONS
Power Requirements
85 to 264 VAC, 50 to 60 Hz, 22 VA max. consumption
Fuse
1A/250V, slow blow, 5x20mm, NSN: 5920008930491
Operating Temperature Range
Storage Temperature Range
Vibration
Weight
Dimensions
Microprocessor
Communication Ports
Reference Pressure
Transducers(RPTs)
15 to 35 °C
- 20 to 70 °C
Meets MIL-T-28800D
6.8 kg (15 lb) max.
32 cm W x 12 cm H x 30 cm D
(12.6 in. x 4.7 in. x 11.8 in.) approx.
Motorola 68302, 16 MHz
RS232 (COM1), RS232 (COM2), IEEE-488
molbox1 A350K 2 x 250 kPa (36 psia) calibrated range
oscillating quartz crystal
molbox1 A700K 2 x 600 kPa (87 psia) calibrated range
oscillating quartz crystal
Pressure Limits
Pressure Connections
Ohmic Measurement System
Gases Supported
Flow Ranges
Valve Driver Option
CE Conformance
© 1995 - 2007 DH Instruments, a Fluke Company
molbox1 A350K
Maximum working pressure
Maximum pressure without damage
250 kPa absolute (36 psia)
350 kPa absolute (50 psia)
molbox1 A700K
Maximum working pressure
Maximum pressure without damage
600 kPa absolute (87 psia)
800 kPa absolute (115 psia)
®
Quick connectors equivalent to Swagelok QM Series (M2-B200)
Resolution
0.004 Ω
Accuracy
± 0.02 % of reading
Accuracy of 100 and 110 Ω reference resistors
± 0.01 %
Stability of 100 and 110 Ω reference resistors
± 0.005 % per 3 yrs
With molbloc-L
Nitrogen (N2), Air, Argon (Ar), Butane (Butn), Carbon
Monoxide (CO), Helium (He), Oxygen (O2), Carbon
Dioxide (CO2), Carbon Tetrafluoride (CF4),
Octofluorocyclobutane (C4F8), Ethane (C2H6),
Ethylene (C2H4), Fluoroform (CHF3),
Hexafluoroethane (C2F6), Hydrogen (H2), Methane
(CH4), Nitrous Oxide (N2O), Propane (C3H8), Sulfur
Hexafluoride (SF6), Xenon (Xe)
With molbloc-S
Nitrogen (N2), Air (dry and humid)
See Section 1.2.5.
(8) 12 V outputs.
Each output can sink 500 mA at 12 V, max. 1 A total (see Section 7.2).
Available. Must be specified.
Page 2
1. INTRODUCTION
1.2.2
REFERENCE PRESSURE TRANSDUCER (RPT)
SPECIFICATIONS
Type
Calibrated Range
Oscillating quartz crystal with mechanical bellows
A350K 0 to 250 kPa absolute (0 to 36 psia)
A700K 0 to 600 kPa absolute (0 to 87 psia)
Resolution
A350K 0.4 Pa (0.00005 psi)
A700K 0.7 Pa (0.0001 psi)
Accuracy
A350K
Absolute pressure
Differential
± 0.02 % FS
± 4 Pa (0.0006 psi) + 0.25 % DP
A700K
Absolute pressure
Differential
1.2.3
± 0.02 % FS
± 5 Pa (0.0007 psi) + 0.03 % DP
TEMPERATURE MEASUREMENT SPECIFICATIONS
Specifications are for molbloc mounted Platinum Resistance Thermometers (PRT) combined
with molbox1 resistance measurement system and temperature calculation.
Range
0 to 40 °C
Accuracy
± 0.05 °C
Resolution
0.01 °C
The molbox1 internal resistance measurement system is automatically calibrated using
reference 100 and 110 Ω (± 0.01 %) resistors (see Section 5.4).
1.2.4
MFC CONTROL FUNCTION (OPTIONAL)
SPECIFICATIONS
ANALOG OUTPUT
Voltage Range
Voltage Accuracy
0 to 6.000 VDC
± 0.05 % FS
Voltage Resolution
0.1 mVDC
Current Range
4 to 20 mA
Current Accuracy
Current Resolution
± 0.05 % FS
0.4 μA
ANALOG INPUT
Voltage Range
Min/Max Measurable Voltage
Voltage Accuracy
Voltage Resolution
Current Range
Current Accuracy
Current Resolution
0 to 5.000 VDC
- 0.25/6.00 VDC
± 0.05 % FS
1 mVDC
4 to 20 mA
± 0.05 % FS
0.4 μA
VALVE TEST POINT
Range
Accuracy
Resolution
+ 2 to + 15 VDC (in reference to - 15 VDC)
± 0.25 % FS
2.5 mVDC
Page 3
© 1995 - 2007 DH Instruments, a Fluke Company
MOLBOX1™ OPERATION AND MAINTENANCE MANUAL
1.2.5 FLOW MEASUREMENT SPECIFICATIONS
molbox1 measures the flow through molbloc flow elements. There are two different types of
molblocs, molbloc-L (laminar) (see Section 1.1.1.1) and molbloc-S (sonic) (see Section
1.1.1.2). Flow measurement specifications, calibration types, ranges and dimensions are
detailed separately for each molbloc type in section 1.2.5.1 and 1.2.5.2.
1.2.5.1
molbloc-L
The flow range, useable operating pressure and absolute and differential
pressure associated with molbloc-L operation depend on the molbloc used and
its pressure-dependent calibration options (see Section 1.2.5.1.1).
Measurement Update
Rate
Range
Resolution
1 second
0 to molbloc full scale depending on gas and molbloc pressure
dependent calibration type (see Section 1.2.5.1.1)
0.0015 % FS
Linearity
± 0.15 % of reading from 10 to 100 % FS,
± 0.015 % FS under 10 % FS
Repeatability
± 0.05 % of reading from 10 to 100 % FS,
± 0.0 5 % FS under 10 % FS
1
± 0.16 % of reading from 10 to 100 % FS,
± 0.016 % FS under 10 % FS
Stability
(1 year)
2
± 0.1 % of reading from 10 to 100 % FS,
± 0.01 % FS under 10 % FS
Measurement
3
Uncertainty
(N2 and any molbox1
supported gas for which
the molbloc in use is
calibrated)
± 0.2 % of reading from 10 to 100 % FS,
± 0.02 % FS under 10 % FS
Precision
3E4 molbloc ± 0.3 % of reading from 10 to 100 % FS,
± 0.03 % FS under 10 % FS
1E5 molbloc ± 0.5% of reading from 25 to 100 % FS,
± 0.05 % FS under 25 % FS
1
Precision: Combined linearity, hysteresis, repeatability.
2
Stability: Maximum change in zero and span over specified time period for typical molbox1 and
molbloc used under typical conditions. As stability can only be predicted, stability for a specific
molbloc and molbox1 should be established from experience.
3
Measurement uncertainty (accuracy): Maximum deviation of the molbox1 flow indication from
the true value of the flow through the molbloc including precision, stability and DHI calibration
standard measurement uncertainty.
1.2.5.1.1
molbloc-L Pressure Dependent Calibration Types
See your molbloc’s Calibration Report to determine the calibration type of
the molbloc you are using.
Different pressure dependent calibration options for molbloc-L elements determine
the range of operating pressures over which a molbloc can be used within its
mass flow measurement specifications. The calibration option also affects the
molbloc flow range and the differential pressure associated with the flow range.
Measurement uncertainty (accuracy) specifications for molbloc-L are valid only
for gases with which the molbloc has been calibrated. All molbloc-L elements
are calibrated for N2. Calibrations with other gases are optional. DHI calibration
capability is not maintained at all times for all gases on all molbloc designations.
Check for availability before ordering calibrations.
© 1995 - 2007 DH Instruments, a Fluke Company
Page 4
1. INTRODUCTION
The molbloc-L pressure dependent calibration types are summarized in Table 1.
Table 1. molbloc-L Pressure Dependent Calibration Types
CALIBRATION TYPE
OPERATING PRESSURE
NOMINAL DIFFERENTIAL
PRESSURE AT MAX. FLOW
1E5
MOLBLOC
ALL OTHER
MOLBLOCS
Full mod,
low pressure
200 to 325 kPa absolute
(29 to 48 psia)
upstream of molbloc
5 kPa (.725
psi)
50 kPa (7.5
psi)
Full mod,
high pressure
325 to 525 kPa absolute
(48 to 76 psia)
upstream of molbloc
Not available
50 kPa (7.5
psi)
Downstream
Atmospheric pressure
downstream of molbloc
12.5 kPa (1.8
psi)
80 kPa (12 psi)
Single P,
low pressure
(non-N2 gases only)
Any specified single molbloc
upstream pressure between
200 and 325 kPa absolute (29
to 48 psia)
5 kPa (.725
psi)
50 kPa (7.5
psi)
Single P,
high pressure
(non-N2 gases only)
Any specified single molbloc
upstream pressure between
325 and 525 kPa absolute (48
to 76 psia)
Not available
50 kPa (7.5
psi)
Differential pressure values are nominal and may vary by up to 15 % with the
actual molbloc used.
Page 5
© 1995 - 2007 DH Instruments, a Fluke Company
MOLBOX1™ OPERATION AND MAINTENANCE MANUAL
1.2.5.1.2
molbloc-L Ranges with Low Pressure Calibrations
Table 2. molbloc-L Ranges with Low Pressure Calibrations
- full mod, low pressure
- full mod, downstream
- single P, low pressure
molbloc-L SIZE AND FULL SCALE FLOW (sccm)
SIZE
1E1
OTHER
FLUOROCARBONS
FLAMMABLE
INERT
GASES
SIZE
5E1
SIZE
1E2
SIZE
2E2
SIZE
5E2
SIZE
1E3
SIZE
5E3
SIZE
1E4
SIZE
3E4
SIZE
1E5
Nitrogen
N2
10
50
100
200
500
1 000
5 000
10 000
30 000
Argon
Ar
10
50
100
200
500
1 000
5 000
10 000
30 000
100 000
80 000
Helium
He
10
50
100
200
500
1 000
5 000
10 000
30 000
100 000
Sulfur Hexafluoride
SF6
10
50
100
200
500
1 000
2 000
500
6 000
1 000
6 000
4 000
Xenon
XE
10
40
80
150
400
800
3 500
500
8 000
11 000
3 000
Butane
C4H10
20
100
130
30
270
50
670
140
2 300
2 200
1 400
7 000
3 000
-----
Ethane
C2H6
20
100
200
400
1 000
2 000
6 000
1 000
18 000
2 000
18 000
6 000
60 000
50 000
Ethylene
C2H4
16
80
160
320
800
1 600
7 000
1 000
16 000
20 000
5 000
70 000
40 000
Hydrogen
----30 000
20 000
-----
H2
20
100
200
400
1 000
2 000
10 000
20 000
60 000
200 000
Methane
CH4
16
80
160
320
800
1 600
8 000
16 000
40 000
5 000
120 000
40 000
Propane
C3H8
20
100
200
400
1 000
2 000
3 000
1 000
10 000
2 000
10 000
7 000
Carbon
Tetrafluoride
CF4
10
50
100
200
500
1 000
4 000
600
10 000
12 000
3 000
Hexafluorethene
C2F6
10
50
100
200
500
1 000
2 000
600
6 000
1 200
6 000
4 000
Trifluoromethane
CHF3
10
50
100
200
500
1 000
4 000
600
10 000
12 000
4 000
38 000
30 000
Air
Air
10
50
100
200
500
1 000
5 000
10 000
30 000
100 000
Carbon Dioxide
CO2
10
50
100
200
500
1 000
5 000
10 000
20 000
4 000
60 000
30 000
Carbon Monoxide
CO
10
50
100
200
500
1 000
5 000
10 000
30 000
100 000
Nitrous Oxide
N2O
10
50
100
200
500
1 000
5 000
10 000
20 000
4 000
60 000
30 000
Octafluorocyclobutane
C4F8
15
60
9
65
17
130
34
330
85
1 100
175
1 050
840
3 400
1 700
---
Oxygen
O2
10
50
100
200
500
1 000
5 000
10 000
30 000
----36 000
25 000
-----
--80 000
A bold value indicates that the maximum flow is limited by the maximum Reynolds number value of 1 200 which is reached
before the normal differential pressure range is reached. In that case, the second value gives the minimum flow for which
measurement uncertainty (accuracy) is ± 0.2 % of the measured value (0.3 % for the 3E4 molbloc, 0.5 % for the 1E5 molbloc).
Where there is no value in the field (--), this indicates that the maximum Reynolds number is reached before the differential
pressure reaches 5 kPa (1 kPa in the case of the 1E5 molbloc-L), therefore calibration with that gas is not useful.
© 1995 - 2007 DH Instruments, a Fluke Company
Page 6
1. INTRODUCTION
1.2.5.1.3
molbloc-L Ranges with High Pressure Calibrations
Table 3. molbloc-L Ranges with High Pressure Calibrations
- full mod, high pressure
- single P, high pressure
molbloc-L SIZE AND FULL SCALE FLOW (sccm)
SIZE
1E1
SIZE
5E1
SIZE
1E2
N2
20
100
200
Ar
20
100
GASES
Nitrogen
OTHER
FLUOROCARBONS
FLAMMABLE
INERT
Argon
SIZE
2E2
SIZE
5E2
SIZE
1E3
SIZE
5E3
SIZE
1E4
SIZE
3E4
SIZE
1E5
400
1 000
2 000
10 000
20 000
40 000
7 500
N/A
200
400
1 000
2 000
10 000
17 000
35 000
6 000
N/A
65 000
N/A
Helium
He
20
100
200
400
1 000
2 000
10 000
20 000
Sulfur Hexafluoride
SF6
25
100
15
120
30
250
50
600
150
2 000
300
2 000
1 400
6 200
2 800
Xenon
XE
20
100
150
350
650
1 700
3 350
950
11 000
1 900
Butane
C4H10
*
*
*
Ethane
C2H6
40
200
350
50
700
100
1 800
200
4 000
6 000
2 300
20 000
4 500
20 000
13 000
N/A
Ethylene
C2H4
40
200
350
700
2 000
4 000
7 000
2 000
22 000
4 000
22 000
12 700
N/A
Hydrogen
H2
40
200
400
900
2 000
4 500
22 000
45 000
130 000
N/A
Methane
CH4
35
175
350
700
1 700
3 500
13 000
2 000
33 000
42 000
12 000
N/A
Propane
C3H8
50
200
25
200
50
400
100
1 000
250
3 500
500
3 500
2 600
11 000
5 400
Carbon
Tetrafluoride
CF4
20
100
200
400
1 000
2 000
3 700
1 200
12 000
2 400
Hexafluorethene
C2F6
25
100
15
120
30
250
50
600
150
2 000
300
1 800
1 500
6 000
3 000
Trifluoromethane
CHF3
25
125
240
30
450
60
1 200
150
2 500
4 000
1 500
12 000
3 000
12 000
8 800
N/A
Air
Air
20
100
200
400
1 000
2 000
10 000
20 000
40 000
7 200
N/A
Carbon Dioxide
CO2
25
125
250
500
1 250
2 500
6 600
1 400
20 000
2 500
20 000
8 800
N/A
Carbon Monoxide
CO
20
100
200
400
1 000
2 000
10 000
20 000
40 000
7 500
N/A
Nitrous Oxide
N2O
25
125
250
500
1 250
2 500
11 000
1 500
20 000
3 000
20 000
9 000
N/A
Octafluorocyclobutane
C4F8
*
Oxygen
O2
20
*
*
100
*
*
200
*
*
400
*
*
*
*
*
*
1 000
2 000
10 000
20 000
--11 000
5 700
*
--12 000
7 300
---
*
40 000
6 500
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
A bold value indicates that the maximum flow is limited by the maximum Reynolds number value of 1 200 which is reached
before the normal differential pressure range is reached. In that case, the second value gives the minimum flow for which
measurement uncertainty (accuracy) is ± 0.2 % of the measured value.
Where there is no value in the field (--), this indicates that the maximum Reynolds number is reached before the differential
pressure reaches 5 kPa, therefore calibration with that gas is not useful.
* is entered in the table when the operating pressure range is greater than the vapor pressure value for the gas.
Page 7
© 1995 - 2007 DH Instruments, a Fluke Company
MOLBOX1™ OPERATION AND MAINTENANCE MANUAL
1.2.5.1.4
molbloc-L Dimensions
molbloc-L SIZES [mm(in.)]
5E3 AND LOWER
1E4, 3E4
1E5
A
58.50 (2.303)
74.50 (2.933)
74.50 (2.933)
B
16.00 (0.630)
24.00 (0.945)
24.00 (0.945)
C
32.00 (1.260) SQ
48.00 (1.890) SQ
48.00 (1.890) SQ
D
68.84 (2.750)
80.00 (3.150)
80.00 (3.150)
E
19.06 (0.750)
28.00 (1.102)
28.00 (1.102)
F
124.00 (4.881)
157.00 (6.181)
164.00 (6.458)
G
1/4 in. VCR M
1/4 in. VCR M
1/2 in. VCR M
1.2.5.2
molbloc-S
The flow range and operating pressure associated with molbloc-S operation
depend on the molbloc used and its calibration options (see Section 1.2.5.2.2)
Measurement Update
Rate
Range
Resolution
1 second
Depends on molbloc-S pressure dependent calibration type
(see Section 1.2.5.2.2)
0.001 % of FS
Linearity
± 0.05 % of reading
Repeatability
± 0.05 % of reading
Precision
1
± 0.1 % of reading
2
± 0.05 % of reading
Predicted Stability
(1 year)
Measurement
3
Uncertainty
With SP molbloc-S
calibration
Measurement
3
Uncertainty
With LP molbloc-S
calibration
A350K
± 0.2 % of reading from 50 to 200 kPa
A700K
± 0.2 % of reading from 50 to 500 kPa
A350K
± 0.2 % of reading from 20 to 200 kPa
A700K
± 0.2 % of reading from 50 to 200 kPa
± 0.2 % of 50 kPa flow from 20 to 50 kPa
1
Precision: Combined linearity, hysteresis, repeatability.
2.
Stability: Maximum change in zero and span over specified time period for typical molbox1 and
molbloc used under typical conditions. As stability can only be predicted, stability for a specific
molbloc and molbox1 should be established from experience.
3.
Measurement uncertainty (accuracy): Maximum deviation of the molbox1 flow indication from
the true value of the flow through the molbloc including precision, stability and DHI calibration
standard measurement uncertainty.
© 1995 - 2007 DH Instruments, a Fluke Company
Page 8
1. INTRODUCTION
1.2.5.2.1
molbloc-S ranges
molbloc-S flow ranges are defined by the molbloc’s Pressure to Flow Conversion
Ratio, KF, the gas used, the absolute pressure that can be delivered upstream of
molbloc-S, the downstream pressure and the acceptable back pressure ratio
(see Section 3.1.5). KF is expressed in units of sccm/kPa and defines the
relationship between mass flow in nitrogen and the absolute upstream pressure
delivered to the molbloc-S. molbloc-S sizes are defined by the nominal KF of the
molbloc-S nozzle, using scientific notation, for example a 1E3 molbloc-S has a KF
of 1 000 sccm/kPa. To differentiate from molbloc-L size designations, this
molbloc size is designated 1E3-S.
The molbox1 pressure range, the molbloc-S calibration type (see Section 1.2.5.2.2)
and the back pressure ratio (BPR) requirements limit the pressures, and flows,
over which a molbloc-S can be used within known measurement uncertainty
limits. In practice, the usable range of a molbloc-S in a given application also may
depend on the available gas supply pressure, the presence and flow capacity of a
vacuum pump downstream or the allowable back pressure on an upstream DUT.
The mass flow range of a molbloc-S element is dependent on the properties of the
gas used, so the range of a molbloc-S is different for each supported gas. The flow
ranges for each molbloc-S size at various typical operating pressures are
summarized separately for each molbloc-S supported gas in the Tables below. For
the common application of using a molbloc-S with its downstream pressure at or
near atmospheric pressure, it is helpful to know what minimum flow can be
measured before violating back pressure ratio requirements (see Section 3.1.5).
In the tables below, this minimum flow value is given in the “Minimum without
vacuum” column. A “t.b.d.” entry in this column indicates that the BPR testing
has yet to be completed for this gas at the time of the printing of this manual.
Table 4: N2. molbloc-S Flow in nitrogen at Various molbloc Upstream Pressures
N2 FLOW [slm @ 0°C] WHEN molbloc-S UPSTREAM PRESSURE IS:[1][2]
molbloc-S
DESIGNATOR
KF
[sccm/kPa]
20 kPa
(3psia)
50 kPa
(7 psia)
100 kPa
(15 psia)
Minimum
without
vacuum[3]
150 kPa
(22 psia)
200 kPa
(30 psia)
250 kPa
(36 psia)
500 kPa
(70 psia)
5E1-S
50
1
2.5
5
7.7
7.5
10
12.5
25
1E2-S
100
2
5
10
15
15
20
25
50
2E2-S
200
4
10
20
28
30
40
50
100
5E2-S
500
10
25
50
67
75
100
125
250
1E3-S
1 000
20
50
100
129
150
200
250
500
2E3-S
2 000
40
100
200
248
300
400
500
1 000
5E3-S
5 000
100
250
500
596
750
1 000
1 250
2500
1E4-S
10 000
200
500
1 000
1 173
1 500
2 000
2 500
5 000
[1] When volumetrically based mass flow units with reference temperatures other than 0°C are used, flow values
will generally be higher; for example, the flow values for a given molbloc and upstream pressure are
approximately 7% higher when expressed in slm @ 20°C. Flow values at a given pressure may vary by up to
5% due to flowpath machining tolerances and rounding.
[2] Flow values in table are valid only when critical flow is established.
[3] Minimum upstream pressure to achieve critical flow with atmospheric pressure (approximately 100 kPa)
downstream of molbloc-S (no vacuum).
Page 9
© 1995 - 2007 DH Instruments, a Fluke Company
MOLBOX1™ OPERATION AND MAINTENANCE MANUAL
Table 5: He. molbloc-S Flow in helium at Various molbloc Upstream Pressures
FLOW [slm @ 0°C] WHEN molbloc-S UPSTREAM PRESSURE IS:[1][2]
molbloc-S
DESIGNATOR
5E1-S
KF
[sccm/kPa]
50
20 kPa
(3psia)
2.4
50 kPa
(7 psia)
6.5
100 kPa
(15 psia)
Minimum
without
vacuum[3]
13
t.b.d.
150 kPa
(22 psia)
20
200 kPa
(30 psia)
27
250 kPa
(36 psia)
34
500 kPa
(70 psia)
69
1E2-S
100
5
13
27
t.b.d.
41
54
68
140
2E2-S
200
10
27
54
t.b.d.
82
110
135
275
5E2-S
500
26
67
135
t.b.d.
205
275
345
695
1E3-S
1 000
53
135
275
t.b.d.
415
555
690
1400
2E3-S
2 000
105
270
550
t.b.d.
830
1100
1400
2800
5E3-S
5 000
270
685
1400
t.b.d.
2100
2800
3500
7000
1E4-S
10 000
545
1400
2750
t.b.d.
4150
5550
6950
14000
[1] When volumetrically based mass flow units with reference temperatures other than 0°C are used, flow values
will generally be higher; for example, the flow values for a given molbloc and upstream pressure are
approximately 7% higher when expressed in slm @ 20°C. Flow values at a given pressure may vary by up to
5% due to flowpath machining tolerances and rounding.
[2] Flow values in table are valid only when critical flow is established.
[3] Minimum upstream pressure to achieve critical flow with atmospheric pressure (approximately 100 kPa)
downstream of molbloc-S (no vacuum).
Table 6: Ar. molbloc-S Flow in argon at Various molbloc Upstream Pressures
FLOW [slm @ 0°C] WHEN molbloc-S UPSTREAM PRESSURE IS:[1][2]
molbloc-S
DESIGNATOR
KF
[sccm/kPa]
20 kPa
(3psia)
50 kPa
(7 psia)
100 kPa
(15 psia)
Minimum
without
vacuum[3]
150 kPa
(22 psia)
200 kPa
(30 psia)
250 kPa
(36 psia)
500 kPa
(70 psia)
5E1-S
50
0.8
2.1
4.3
t.b.d.
6.5
8.7
11
1E2-S
100
1.7
4.3
8.7
t.b.d.
13
18
22
22
44
2E2-S
200
3.4
8.6
17
t.b.d.
26
35
44
88
5E2-S
500
8.5
22
44
t.b.d.
66
88
110
220
1E3-S
1 000
17
44
88
t.b.d.
130
175
220
445
2E3-S
2 000
34
87
175
t.b.d.
265
355
440
890
5E3-S
5 000
87
220
440
t.b.d.
660
885
1100
2200
1E4-S
10 000
175
440
880
t.b.d.
1350
1750
2200
4450
[1] When volumetrically based mass flow units with reference temperatures other than 0°C are used, flow values
will generally be higher; for example, the flow values for a given molbloc and upstream pressure are
approximately 7% higher when expressed in slm @ 20°C. Flow values at a given pressure may vary by up to
5% due to flowpath machining tolerances and rounding.
[2] Flow values in table are valid only when critical flow is established.
[3] Minimum upstream pressure to achieve critical flow with atmospheric pressure (approximately 100 kPa)
downstream of molbloc-S (no vacuum).
© 1995 - 2007 DH Instruments, a Fluke Company
Page 10
1. INTRODUCTION
Table 7: H2. molbloc-S Flow in hydrogen at Various molbloc Upstream Pressures
FLOW [slm @ 0°C] WHEN molbloc-S UPSTREAM PRESSURE IS:[1][2]
molbloc-S
DESIGNATOR
KF
[sccm/kPa]
20 kPa
(3psia)
50 kPa
(7 psia)
100 kPa
(15 psia)
Minimum
without
vacuum[3]
150 kPa
(22 psia)
200 kPa
(30 psia)
250 kPa
(36 psia)
500 kPa
(70 psia)
5E1-S
50
3.3
8.7
18
t.b.d.
27
36
46
92
1E2-S
100
6.8
18
36
t.b.d.
54
73
92
185
2E2-S
200
14
36
73
t.b.d.
110
145
185
370
5E2-S
500
35
90
185
t.b.d.
275
370
460
930
1E3-S
1 000
71
180
365
t.b.d.
550
740
925
1850
2E3-S
2 000
145
365
735
t.b.d.
1100
1500
1850
3700
5E3-S
5 000
360
915
1850
t.b.d.
2800
3700
4650
9300
1E4-S
10 000
730
1850
3700
t.b.d.
5550
7450
9300
18650
[1] When volumetrically based mass flow units with reference temperatures other than 0°C are used, flow values
will generally be higher; for example, the flow values for a given molbloc and upstream pressure are
approximately 7% higher when expressed in slm @ 20°C. Flow values at a given pressure may vary by up to
5% due to flowpath machining tolerances and rounding.
[2] Flow values in table are valid only when critical flow is established.
[3] Minimum upstream pressure to achieve critical flow with atmospheric pressure (approximately 100 kPa)
downstream of molbloc-S (no vacuum).
Table 8: O2. molbloc-S Flow in oxygen at Various molbloc Upstream Pressures
FLOW [slm @ 0°C] WHEN molbloc-S UPSTREAM PRESSURE IS:[1][2]
molbloc-S
DESIGNATOR
5E1-S
KF
[sccm/kPa]
50
20 kPa
(3psia)
50 kPa
(7 psia)
100 kPa
(15 psia)
Minimum
without
vacuum[3]
0.9
2.2
4.5
t.b.d.
150 kPa
(22 psia)
6.8
200 kPa
(30 psia)
9.2
250 kPa
(36 psia)
11
500 kPa
(70 psia)
23
1E2-S
100
1.7
4.5
9.1
t.b.d.
14
18
23
46
2E2-S
200
3.5
9
18
t.b.d.
28
37
46
93
5E2-S
500
8.9
23
46
t.b.d.
69
93
115
235
1E3-S
1 000
18
46
92
t.b.d.
140
185
230
465
2E3-S
2 000
36
92
185
t.b.d.
280
370
465
935
5E3-S
5 000
91
230
465
t.b.d.
695
930
1150
2350
1E4-S
10 000
185
460
930
t.b.d.
1400
1850
2350
4650
[1] When volumetrically based mass flow units with reference temperatures other than 0°C are used, flow values
will generally be higher; for example, the flow values for a given molbloc and upstream pressure are
approximately 7% higher when expressed in slm @ 20°C. Flow values at a given pressure may vary by up to
5% due to flowpath machining tolerances and rounding.
[2] Flow values in table are valid only when critical flow is established.
[3] Minimum upstream pressure to achieve critical flow with atmospheric pressure (approximately 100 kPa)
downstream of molbloc-S (no vacuum).
Page 11
© 1995 - 2007 DH Instruments, a Fluke Company
MOLBOX1™ OPERATION AND MAINTENANCE MANUAL
Table 9: CH4. molbloc-S Flow in methane at Various molbloc Upstream Pressures
FLOW [slm @ 0°C] WHEN molbloc-S UPSTREAM PRESSURE IS:[1][2]
molbloc-S
DESIGNATOR
KF
[sccm/kPa]
20 kPa
(3psia)
50 kPa
(7 psia)
100 kPa
(15 psia)
Minimum
without
vacuum[3]
150 kPa
(22 psia)
200 kPa
(30 psia)
250 kPa
(36 psia)
500 kPa
(70 psia)
5E1-S
50
1.2
3.1
6.3
t.b.d.
9.5
13
16
1E2-S
100
2.4
6.2
13
t.b.d.
19
25
32
32
64
2E2-S
200
4.9
13
25
t.b.d.
38
51
64
130
5E2-S
500
12
31
64
t.b.d.
96
130
160
320
1E3-S
1 000
25
63
125
t.b.d.
190
255
320
645
2E3-S
2 000
50
125
255
t.b.d.
385
515
640
1300
5E3-S
5 000
125
320
640
t.b.d.
960
1300
1600
3200
1E4-S
10 000
255
640
1300
t.b.d.
1900
2550
3200
6450
[1] When volumetrically based mass flow units with reference temperatures other than 0°C are used, flow values
will generally be higher; for example, the flow values for a given molbloc and upstream pressure are
approximately 7% higher when expressed in slm @ 20°C. Flow values at a given pressure may vary by up to
5% due to flowpath machining tolerances and rounding.
[2] Flow values in table are valid only when critical flow is established.
[3] Minimum upstream pressure to achieve critical flow with atmospheric pressure (approximately 100 kPa)
downstream of molbloc-S (no vacuum).
Table 10: CO. molbloc-S Flow in carbon monoxide at Various molbloc Upstream Pressures
FLOW [slm @ 0°C] WHEN molbloc-S UPSTREAM PRESSURE IS:[1][2]
molbloc-S
DESIGNATOR
5E1-S
KF
[sccm/kPa]
50
20 kPa
(3psia)
1
50 kPa
(7 psia)
2.5
100 kPa
(15 psia)
Minimum
without
vacuum[3]
5
t.b.d.
150 kPa
(22 psia)
7.5
200 kPa
(30 psia)
10
250 kPa
(36 psia)
12.5
500 kPa
(70 psia)
25
1E2-S
100
2
5
10
t.b.d.
15
20
25
50
2E2-S
200
4
10
20
t.b.d.
30
40
50
100
5E2-S
500
10
25
50
t.b.d.
75
100
125
250
1E3-S
1 000
20
50
100
t.b.d.
150
200
250
500
2E3-S
2 000
40
100
200
t.b.d.
300
400
500
1 000
5E3-S
5 000
100
250
500
t.b.d.
750
1 000
1 250
2500
1E4-S
10 000
200
500
1 000
t.b.d.
1 500
2 000
2 500
5 000
[1] When volumetrically based mass flow units with reference temperatures other than 0°C are used, flow values
will generally be higher; for example, the flow values for a given molbloc and upstream pressure are
approximately 7% higher when expressed in slm @ 20°C. Flow values at a given pressure may vary by up to
5% due to flowpath machining tolerances and rounding.
[2] Flow values in table are valid only when critical flow is established.
[3] Minimum upstream pressure to achieve critical flow with atmospheric pressure (approximately 100 kPa)
downstream of molbloc-S (no vacuum).
© 1995 - 2007 DH Instruments, a Fluke Company
Page 12
1. INTRODUCTION
Table 11: Air. molbloc-S Flow in air at Various molbloc Upstream Pressures
FLOW [slm @ 0°C] WHEN molbloc-S UPSTREAM PRESSURE IS:[1][2]
molbloc-S
DESIGNATOR
KF
[sccm/kPa]
20 kPa
(3psia)
50 kPa
(7 psia)
100 kPa
(15 psia)
Minimum
without
vacuum[3]
150 kPa
(22 psia)
200 kPa
(30 psia)
250 kPa
(36 psia)
500 kPa
(70 psia)
5E1-S
50
1
2.5
5
7.7
7.5
10
12.5
1E2-S
100
2
5
10
15
15
20
25
25
50
2E2-S
200
4
10
20
28
30
40
50
100
5E2-S
500
10
25
50
67
75
100
125
250
1E3-S
1 000
20
50
100
129
150
200
250
500
2E3-S
2 000
40
100
200
248
300
400
500
1 000
5E3-S
5 000
100
250
500
596
750
1 000
1 250
2500
1E4-S
10 000
200
500
1 000
1 173
1 500
2 000
2 500
5 000
[1] When volumetrically based mass flow units with reference temperatures other than 0°C are used, flow values
will generally be higher; for example, the flow values for a given molbloc and upstream pressure are
approximately 7% higher when expressed in slm @ 20°C. Flow values at a given pressure may vary by up to
5% due to flowpath machining tolerances and rounding.
[2] Flow values in table are valid only when critical flow is established.
[3] Minimum upstream pressure to achieve critical flow with atmospheric pressure (approximately 100 kPa)
downstream of molbloc-S (no vacuum).
Table 12: N2O. molbloc-S Flow in nitrous oxide at Various molbloc Upstream Pressures
FLOW [slm @ 0°C] WHEN molbloc-S UPSTREAM PRESSURE IS:[1][2]
molbloc-S
DESIGNATOR
5E1-S
KF
[sccm/kPa]
50
20 kPa
(3psia)
0.7
50 kPa
(7 psia)
100 kPa
(15 psia)
Minimum
without
vacuum[3]
1.9
3.8
t.b.d.
150 kPa
(22 psia)
5.7
200 kPa
(30 psia)
7.6
250 kPa
(36 psia)
9.5
500 kPa
(70 psia)
19
1E2-S
100
1.5
3.7
7.5
t.b.d.
11
15
19
39
2E2-S
200
2.9
7.5
15
t.b.d.
23
31
38
77
5E2-S
500
7.4
19
38
t.b.d.
57
76
96
195
1E3-S
1 000
15
38
76
t.b.d.
115
155
190
385
2E3-S
2 000
30
76
150
t.b.d.
230
305
385
775
5E3-S
5 000
75
190
380
t.b.d.
575
765
960
1950
1E4-S
10 000
150
380
765
t.b.d.
1150
1550
1900
3850
[1] When volumetrically based mass flow units with reference temperatures other than 0°C are used, flow values
will generally be higher; for example, the flow values for a given molbloc and upstream pressure are
approximately 7% higher when expressed in slm @ 20°C. Flow values at a given pressure may vary by up to
5% due to flowpath machining tolerances and rounding.
[2] Flow values in table are valid only when critical flow is established.
[3] Minimum upstream pressure to achieve critical flow with atmospheric pressure (approximately 100 kPa)
downstream of molbloc-S (no vacuum).
Page 13
© 1995 - 2007 DH Instruments, a Fluke Company
MOLBOX1™ OPERATION AND MAINTENANCE MANUAL
Table 13: SF6. molbloc-S Flow in sulfur hexafluoride at Various molbloc Upstream Pressures
FLOW [slm @ 0°C] WHEN molbloc-S UPSTREAM PRESSURE IS:[1][2]
molbloc-S
DESIGNATOR
KF
[sccm/kPa]
20 kPa
(3psia)
50 kPa
(7 psia)
100 kPa
(15 psia)
Minimum
without
vacuum[3]
150 kPa
(22 psia)
200 kPa
(30 psia)
250 kPa
(36 psia)
500 kPa
(70 psia)
5E1-S
50
0.4
1
1.9
t.b.d.
2.9
3.9
4.9
1E2-S
100
0.8
1.9
3.9
t.b.d.
5.9
7.9
9.9
9.9
20
2E2-S
200
1.5
3.9
7.8
t.b.d.
12
16
20
40
5E2-S
500
3.9
9.8
20
t.b.d.
30
40
49
100
1E3-S
1 000
7.8
20
39
t.b.d.
59
79
99
200
2E3-S
2 000
16
39
79
t.b.d.
120
160
200
400
5E3-S
5 000
39
98
195
t.b.d.
295
395
495
1000
1E4-S
10 000
78
195
395
t.b.d.
595
790
990
2000
[1] When volumetrically based mass flow units with reference temperatures other than 0°C are used, flow values
will generally be higher; for example, the flow values for a given molbloc and upstream pressure are
approximately 7% higher when expressed in slm @ 20°C. Flow values at a given pressure may vary by up to
5% due to flowpath machining tolerances and rounding.
[2] Flow values in table are valid only when critical flow is established.
[3] Minimum upstream pressure to achieve critical flow with atmospheric pressure (approximately 100 kPa)
downstream of molbloc-S (no vacuum).
Table 14: CO2. molbloc-S Flow in carbon dioxide at Various molbloc Upstream Pressures
FLOW [slm @ 0°C] WHEN molbloc-S UPSTREAM PRESSURE IS:[1][2]
molbloc-S
DESIGNATOR
5E1-S
KF
[sccm/kPa]
20 kPa
(3psia)
50
0.7
1E2-S
100
2E2-S
200
5E2-S
50 kPa
(7 psia)
100 kPa
(15 psia)
Minimum
without
vacuum[3]
150 kPa
(22 psia)
5.7
200 kPa
(30 psia)
7.6
250 kPa
(36 psia)
9.6
500 kPa
(70 psia)
1.9
3.8
t.b.d.
19
1.5
3.7
7.6
t.b.d.
11
15
19
39
3
7.5
15
t.b.d.
23
31
38
77
500
7.5
19
38
t.b.d.
57
77
96
195
1E3-S
1 000
15
38
76
t.b.d.
115
155
195
390
2E3-S
2 000
30
76
155
t.b.d.
230
310
385
775
5E3-S
5 000
76
190
385
t.b.d.
575
770
965
1950
1E4-S
10 000
150
385
770
t.b.d.
1150
1550
1950
3900
[1] When volumetrically based mass flow units with reference temperatures other than 0°C are used, flow values
will generally be higher; for example, the flow values for a given molbloc and upstream pressure are
approximately 7% higher when expressed in slm @ 20°C. Flow values at a given pressure may vary by up to
5% due to flowpath machining tolerances and rounding.
[2] Flow values in table are valid only when critical flow is established.
[3] Minimum upstream pressure to achieve critical flow with atmospheric pressure (approximately 100 kPa)
downstream of molbloc-S (no vacuum).
© 1995 - 2007 DH Instruments, a Fluke Company
Page 14
1. INTRODUCTION
1.2.5.2.2
molbloc-S Pressure Dependent Calibration Types
See your molbloc’s Calibration Report to determine the calibration type of
the molbloc you are using.
Measurement uncertainty (accuracy) specifications for molblocs are valid only for
gases with which the molbloc has been calibrated. All molbloc-S elements are
calibrated in one standard gas, either air or N2, and may be calibrated in other
gases. Calibrations with other gases are optional. The set of gases which can
be measured by molbloc-S is separate from the list of molbloc-L gases, and may
be more limited. DHI calibration capability is not maintained at all times for all
gases on all molbloc designations. Check for availability before ordering calibrations.
molbloc-S calibrations are performed over flow ranges corresponding to one of
two pressure ranges, summarized in Table 15.
Table 15. molbloc-S Calibration Types
CALIBRATION TYPE
LP
OPERATING PRESSURE
low pressure
20 to 200 kPa absolute (3 to
30 psia
upstream of molbloc
standard pressure
50 to 500 kPa absolute(7 to 70
psia)
upstream of molbloc
SP
molbloc-S flow measurements are valid only when the ratio of pressure
downstream and pressure upstream of the nozzle is high enough to assure a
critical (choked) flow (see Section 3.1.5).
Page 15
© 1995 - 2007 DH Instruments, a Fluke Company
MOLBOX1™ OPERATION AND MAINTENANCE MANUAL
1.2.5.2.3
molbloc-S Dimensions
molbloc-S SIZE [mm(in.)]
5E1-S
A
B
C
D
E
F
G
H
I
J
K
L
48.0 (1.89) SQ
1E2-S
48.0 (1.89)SQ
2E2-S
48.0 (1.89) SQ
5E2-S
48.0 (1.89) SQ
1E3-S
48.0 (1.89) SQ
2E3-S
48.0 (1.89) SQ
5E3-S
80.0 (3.15) SQ
1E4-S
80.0 (3.15) SQ
24.0 (0.94)
24.0 (0.94)
24.0 (0.94)
24.0 (0.94)
24.0 (0.94)
24.0 (0.94)
40.0 (1.57)
40.0 (1.57)
48.0 (1.89) SQ
48.0 (1.89)SQ
48.0 (1.89) SQ
48.0 (1.89) SQ
48.0 (1.89) SQ
48.0 (1.89) SQ
80.0 (3.15) SQ
80.0 (3.15) SQ
80.0 (3.15)
80.0 (3.15)
80.0 (3.15)
80.0 (3.15)
80.0 (3.15)
80.0 (3.15)
176.0 (6.93)
28.0 (1.10)
28.0 (1.10)
28.0 (1.10)
28.0 (1.10)
28.0 (1.10)
28.0 (1.10)
44.0 (1.73)
167.5 (6.59)
167.5 (6.59)
171.0 (6.73)
171.0 (6.73)
171.0 (6.73)
175.0 (6.89) [1]
KF16 FLANGE
KF16 FLANGE
KF16 FLANGE
KF16 FLANGE
KF16 FLANGE
KF16 FLANGE
KF40 FLANGE
KF40 FLANGE
100.0 (3.94)
100.0 (3.94)
84.0 (3.31)
84.0 (3.31)
84.0 (3.31)
84.0 (3.31)
154.0 (6.06)
154.0 (6.06)
128.0 (5.04)
128.0 (5.04)
128.0 (5.35)
128.0 (5.35)
128.0 (5.35)
128.0 (5.35)
236.0 (9.29)
236.0 (9.29)
73.0 (2.87)
73.0 (2.87)
73.0 (2.87)
73.0 (2.87)
73.0 (2.87)
73.0 (2.87)
106.0 (4.17)
106.0 (4.17)
167.5 (6.59)
167.5 (6.59)
171.0 (6.73)
171.0 (6.73)
171.0 (6.73)
171.0 (6.73)
290.0 (11.42)
290.0 (11.42)
¼” VCR Male[2]
¼” VCR Male[2]
1” NPT M[2]
1” NPT M[2]
½” VCR M[2]
½” VCR M[2]
½” VCR M[2]
½” VCR M[2]
299.7 (11.80) [1]
176.0 (6.93)
44.0 (1.73)
331.0 (13.03) [1]
[1] On some molbloc-S elements, the
venturi nozzle extends beyond the
molbloc downstream flange, making
the overall length dimension, F, longer
than the fitting to fitting length
dimension, K. The nozzle overhang
may interfere with some molbloc-S
downstream connections or the
connection of a blank off cap for leak
testing, so a 40 mm diameter ISO-KF
nipple is supplied with 5E3-S and
1E4-S molblocs.
[2] Default connector type is listed.
Additional upstream connector options
may be available. Contact your DHI
Sales Representative for details.
© 1995 - 2007 DH Instruments, a Fluke Company
Page 16
1. INTRODUCTION
1.2.6
FRONT AND REAR PANELS
1.2.6.1
FRONT PANEL
The front panel assembly provides a 2 x 20 vacuum fluorescent display, a
membrane keypad for local user interface and other LED indicators.
1.
2 x 2 Display
3.
Channel Indicator
2.
Multi-function Keypad
4.
Remote Operation Indicator
Figure 1. Front Panel
1.2.6.2
REAR PANEL
The rear panel assembly provides pressure and electrical connections for two molbloc
mass flow elements, communications interfaces and the power connection module.
1.
Connection for External DMM (Option)
8.
Host Communications (RS232)
2.
External Drivers Connection (Option)
9.
On/Off Switch
3.
MFC Switchbox Connection
10. Fuse
4.
RS485 Connection (not used)
11. molbloc Electrical Connection (Channel B)
5.
Host Communications (IEEE-488)
12. molbloc Pressure Connections (Channel B)
6.
MFC Analog Control Connection
13. molbloc Pressure Connections (Channel A)
7.
Remote Communication for External Device (RS232)
14. molbloc Electrical Connection (Channel A)
Figure 2. Rear Panel
Page 17
© 1995 - 2007 DH Instruments, a Fluke Company
MOLBOX1™ OPERATION AND MAINTENANCE MANUAL
NOTES
© 1995 - 2007 DH Instruments, a Fluke Company
Page 18
2. INSTALLATION
2. INSTALLATION
2.1
UNPACKING AND INSPECTION
2.1.1 REMOVING FROM PACKAGING
molbox1 is delivered, along with its standard accessories, in a corrugated container with foam
end caps to hold it in place.
Remove the molbox1 and its accessories from the shipping container and remove each
element from its protective plastic bag.
2.1.2 INSPECTING CONTENTS
Check that all items are present and have NO visible damage.
A molbox1 includes:
Table 16. molbox1 Parts List
DESCRIPTION
PART #
molbox1 molbloc Monitor
FAM0004
Report of Calibration
550100
ACCESSORIES INCLUDING:
1
Operation and Maintenance Manual
550089
1
Power Cord (7.5 ft.)
4
molbox to molbloc pressure connecting tubes
2
molbox to molbloc electrical/data connection cables
100770
or 100770-CE
401125
102096
or 102096-CE
2
Straight through quick connector stems
101889*
1
Rubber Feet Cap Set (4)
400202
1
MFC Cable and Connections Kit (if MFC Option
included)
1
General Accessories Disk (white)
(Important: Includes system support software and
documentation.)
401230
or 401230-CE
102987
* Equivalent to Swagelok P/N SS-QM2-S-200
Page 19
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MOLBOX1™ OPERATION AND MAINTENANCE MANUAL
2.2
SITE REQUIREMENTS
Install molbox1 on any stable surface at a convenient height. The front feet are extendible so that the unit
can be inclined for easier viewing. Four rubber feet caps are provided in the accessories and can be
installed if desired. These prevent the unit from slipping on smooth surfaces.
The molbox1 can also be mounted in a standard 19 in. rack mount using the optional rack mount kit (P/N
401465). For additional information, contact your DHI Representative.
When installing molbox1, consideration should be given to where the molbloc flow measuring element
and associated hardware will be located. molbox1 may be placed on a shelf or cart at a different height
than the molbloc, but the distance between the molbloc and molbox is limited by the length of the cable
and pneumatic lines connecting them. If you will locate the molbox at a different height than the molbloc,
the small errors that would be associated with the difference in pressure can be removed using the
molbox1 head correction (see Section 3.6.8).
If the molbloc/molbox system is being used to calibrate other devices (DUTs), the molbloc may need to be
connected upstream or downstream of the DUT to operate within the pressure limits of the molbloc’s
calibration type (see Sections 1.2.5.1.1, 2.2.5.2.2) and to accommodate the pressure requirements of the DUT.
See the molbloc’s Calibration Report to determine the calibration type of the molbloc you are using.
If the molbloc is connected upstream of the DUT, it is important to supply the molbloc with a stable
regulated gas source. The volume present between the molbloc and the device to be calibrated should
be minimized, for low flows.
In some cases, molbloc-S is used with a vacuum source downstream to reduce the pressure at which
critical flow is reached. Consider the placement of the vacuum pump and connections. Generally, a large
vacuum pump is needed that should be isolated from the work area due to noise and oil vapor
considerations. If the vacuum pump and/or vacuum kit was purchased from DHI, see the instruction
sheets and/or manuals that are included with the hardware.
Optional molstics are offered for mounting molblocs. They provide a convenient means of addressing
supply regulation, filtering and interconnection issues with high quality, configured hardware. For additional
information, contact your DHI Representative.
If a DUT is located upstream of the molbloc and is contaminated, contaminates may flow from the
DUT to the molbloc and alter the molbloc calibration. If the DUT must be connected upstream of the molbloc,
be sure it is clean before flowing and consider installing a filter between the DUT and the molbloc.
© 1995 - 2007 DH Instruments, a Fluke Company
Page 20
2. INSTALLATION
2.3
INITIAL SETUP
2.3.1 PREPARING FOR OPERATION
To prepare molbox1 for check out and operation:
n Remove the plastic caps from the molbox1 rear panel pressure connections.
o Remove the protective plastic sheet from the front panel display.
p Familiarize yourself briefly with the front and rear panels (see Section 1.2.6).
q Follow the steps described in Sections 2.3.2 to 2.3.7.
2.3.2 POWER CONNECTION
Connect the power cable supplied to molbox1 and to a power source. Power requirements
are 85 to 264 VAC, 50 to 60 Hz, 22 VA max. consumption.
2.3.3 molbox1 TO molbloc CONNECTIONS
There are two molbloc connection channels on molbox1. Each has two pressure connections
(upstream and downstream) and one electrical/data connection. Select a channel to use or
connect a separate molbloc to each channel.
For the pressure connections, use the molbox1 to molbloc pressure tubes (P/N 401125)
supplied with the molbox1. Following the color coding on the pressure lines, connect the
upstream (HI) molbox1 rear panel quick connector to the upstream port of the molbloc and
the downstream (LO) quick connector to the downstream port. To connect the quick
connectors, first pull back the knurled sleeve on the quick connector body, then insert the
quick connector stem and push firmly on the quick connectors until they click into place to
assure that the connection is properly completed.
For the electrical/data connection, use the molbox to molbloc electrical/data connection cable
(P/N 102096). Connect the cable to the molbloc and then to molbox1 rear panel connector
labeled molbloc.
Avoid making or breaking molbloc electrical connections to the molbox1 while the molbox
power is ON. Damage to the molbloc EEPROM may result.
2.3.4 GAS SUPPLY AND FLOWPATH CONNECTIONS
Connect a gas supply to the molbloc. Gas supply requirements are:
•
The gas supply must be clean and dry (especially free from oil and particulates) to avoid
contaminating the molbloc.
•
For correct measurements, the gas must be of the same species as that selected by the
molbox1 GAS function (see Section 3.4.2). Gas purity affects the measurement
uncertainty of flow measurements as molbox1 uses the thermodynamic properties of the
flowing gas in its flow calculations. Generally, gases with purity of 99.9 % or better are
used for molbloc measurements. Except when using ambient air with molbloc-S, the test
gas should be free of any humidity (dewpoint less than – 40 °C).
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MOLBOX1™ OPERATION AND MAINTENANCE MANUAL
•
If the molbloc is connected upstream of the DUT, the supply pressure must be regulated
and stable within the limits of the molbloc-L pressure dependent calibration type (see
Section 1.2.5.1.1.1) or molbloc-S calibration type (see section 1.2.5.2.2). If the molbloc
is connected downstream of the DUT, use regulators and valves to make sure that the
pressure that is delivered to the molbloc will be within the limits of the molbloc calibration type.
•
Care should also be taken to make sure that the pressure and flow supplied to the
molbloc are always low enough to avoid over pressuring the molbox1 RPTs(see
Sections 1.2.2, 3.1.4). If a DUT upstream of the molbloc is operated at high pressure, a
pressure reducing regulator should be connected between the DUT and the molbloc to
ensure that even momentary high pressure spikes do not reach the molbox RPTs.
The gas supplied to the molbloc should be clean and dry. Contamination of the molbloc
flow passage with liquids, particulates or any other matter will alter the molbloc
calibration and can lead to out of tolerance flow measurements.
NEVER connect a pressure source to the molbloc that is greater than the overpressure
limit of your molbox1. molbox1 A350K overpressure limit is 275 kPa absolute/175 kPa
gauge (40 psia/25 psig). molbox1 A700K overpressure limit is 650 kPa absolute/550 kPa
gauge (95 psia/80 psig). Overpressure can damage the molbox1 internal RPTs (see
Section 1.2.2, 3.1.4).
If you are using a DHI molstic: Install the molbloc into the molstic and connect a gas
supply following the molstic instruction sheet or manual. The flow through the molbloc must
be in the direction of the arrow engraved on the molbloc.
If you are NOT using a DHI molstic: Connect a gas supply to the molbloc according to the
molbloc instruction sheet and the pressure limits of the molbloc calibration type. A valve
should be installed between the pressure supply and the molbloc to allow flow to the molbloc
to be interrupted. The flow through the molbloc must be in the direction of the arrow
engraved on the molbloc.
Adaptor kits are available from DHI to make connections from the molbloc or molstic fittings
to other common connector types. Ask you DHI Sales Representative about your specific
adaptor requirements.
Operating at pressures other than those of the molbloc-L pressure dependent calibration type
(see Section 1.2.5.1.1) or molbloc-S calibration type may result in out of tolerance flow
measurements. Refer to the molbloc Calibration Report to determine its calibration type.
2.3.5 VACUUM SUPPLY (molbloc-S ONLY)
In some cases molbloc-S is operated with a vacuum downstream of the molbloc to reduce
the back pressure so that critical flow can be reached at a lower upstream pressure (see
Section 3.1.5).
There is no lower limit to the pressure that may safely be applied to molbox1 RPTs.
If you are using DHI supplied downstream vacuum connect kit and vacuum pump:
Install the kit and pump following the supplied instruction sheet or manual. Carefully follow
the pump manufacturer’s recommendations for pump operation.
© 1995 - 2007 DH Instruments, a Fluke Company
Page 22
2. INSTALLATION
If you are NOT using DHI supplied downstream vacuum connect kit and vacuum pump:
Carefully evaluate vacuum pump specifications to be sure that the vacuum source available
has the pumping speed necessary to safely handle the planned flows and to maintain low
enough pressure at planned flow rates.
Be sure to provide facilities to avoid flowing into the pump when the pump is not ON as this
will cause pressure to build up on the pump and may damage it. Normally, a shut-off valve
should be included between the pump and the molbloc-S.
It is preferable to install a check valve with very low cracking pressure between the molbloc
and the vacuum shut-off valve.
Adaptor kits are available from DHI to make connections from the molbloc or molstic fittings
to other common connector types. Ask you DHI Sales Representative about your specific
adaptor requirements.
Operating at pressures other than those of the molbloc-S calibration type may result in
out of tolerance flow measurements (see Section 1.2.5.2.2). Refer to the molbloc
Calibration Report to determine its calibration type.
2.3.6 COMMUNICATIONS CONNECTIONS
If molbox1 is being interfaced to a computer, connect an RS232 cable to molbox1 COM1 or
an IEEE-488 cable (cables not supplied) to the molbox1 IEEE-488 interface. Configure the
interface (see Section 0).
2.3.7 MFC CONTROL OPTION CONNECTION
If the molbox1 is equipped with the MFC control option, a cable and connection kit will have
been supplied with the molbox1 accessories. Configure the cable correctly using the pinout
information provided in Section 7.3 and information from the MFC manufacturer.
2.4
POWER UP AND VERIFICATION
2.4.1 POWER UP
Actuate the power switch on the molbox1 rear panel. Observe the front panel display as
molbox1 initializes, error checks, calibrates its internal ohmic measurement system and goes
to the main run screen (see Section 3.2). The top left side of the main run screen should
display a flow value near zero or <BPR HI>. If <NO BLOC> is displayed, molbox1 has not
been able to identify a molbloc connection and load molbloc information. Verify that a valid
molbloc is properly connected (see Section 2.3.3) and press [SETUP], <1molbloc> to load
the molbloc (see Section 3.5.1). If molbox1 is still unable to identify a molbloc, the molbloc
may require reloading of EEPROM information or molbox1 may require repair.
If the molbox1 fails to reach the main run screen: Service may be required. Record the
sequence of operations and displays observed and contact a DHI Authorized Service
Provider (see Section 7.4).
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MOLBOX1™ OPERATION AND MAINTENANCE MANUAL
2.4.2 CHECK PROPER PRESSURE MEASUREMENT OPERATION
Check that the molbox pressure measurements are operating properly. Proceed as follows:
n Connect the molbloc to the molbox1 (see Section 2.3.3).
o Shut off the gas supply to the molbloc and open one or both molbloc ends to atmospheric
(ambient) pressure.
p Press [P&T] and observe the display of the pressure measured by the upstream and
downstream absolute RPTs (see Section 3.4.5).
Observe the upstream and
downstream pressures. These should indicate current atmospheric pressure and be in
agreement within ± 0.2 kPa (0.03 psi). If the two readings disagree by more than
± 0.2 kPa (0.03 psi), one or both RPTs may be out of calibration and service may
be required.
q Press [ESCAPE] to return to the main run screen.
2.4.3
CHECK PROPER TEMPERATURE MEASUREMENT
OPERATION
Check that the molbox1 temperature measurement is operating properly. Proceed as follows:
n Connect a molbloc to the molbox1 (see Section 2.3.3).
o From the molbox1 main run screen, press [P&T] twice to arrive at the temperature display
screen. Observe the temperature readings of the two molbloc PRTs (see Section 3.4.5).
If the molbloc has been in a stable temperature environment for 30 to 60 minutes, the temperature
indications should be roughly ambient temperature and the two indications should agree
within ± 0.2 °C. If the two readings disagree by more than ± 0.2 °C, there may be a problem
with the molbloc or the molbox1 TEMPERATURE MEASUREMENT function and service
may be required.
2.4.4
CHECK THE MFC CONTROL FUNCTION (OPTIONAL)
Using the front panel keypad, display select MFC profile #1 for a voltage MFC or #2 for a
current MFC (see Section 3.4.8). Using [ENTER] to select MFC setpoints and observing the
MFC display screens, check that the MFC control operation is normal. If operation does not
appear to be correct, check the MFC cable configuration and connection. Check the
recommendations in Section 2.5 and the Troubleshooting Guide in Section 6 prior to
contacting a DHI Authorized Service Provider (Section 7.4).
2.4.5
LEAK CHECK
It is recommended that a new molbox1 be leak checked at start-up to assure that no internal
leaks developed during shipping and handling. See Section 3.4.4.3 to run the molbox1
on-board INTERNAL LEAK CHECKING function.
© 1995 - 2007 DH Instruments, a Fluke Company
Page 24
2. INSTALLATION
2.4.6
CHECK/SET SECURITY LEVEL
molbox1 has a security system based on user levels. By default, the security system is set to
“low”, which includes certain access restrictions, and there is no password required to change
the security level. See Section 0 for information on the security level system. As part of the
molbox1 startup, set your desired security level and a password.
molbox1 is delivered with the security level set to “low” to avoid inadvertent altering of
critical internal settings but with access to changing security levels unrestricted. It is
recommended that at least the low security level be maintained at all times and
password protection be implemented if control over setting of security levels is desired.
2.5
ADDITIONAL PRECAUTIONS TO TAKE BEFORE MAKING
FLOW MEASUREMENTS
Before using the molbox1 to make meaningful flow measurements, consider the following:
•
The pressure measuring RPTs must be tared at the operating line pressure (see Section 3.4.4.1).
•
Operating pressure and flow range should be within the limits of the molbloc calibration type and
molbloc size for the flowing gas (see Section 1.2.5).
•
Be sure that the gas pressure connected to the molbloc is not great enough to overpressure the
molbox1 internal RPTs.
•
The gas type selected should be the gas flowing through the molbloc (see Section 3.4.2).
•
For flow measurement uncertainty within molbox1 specifications, the gas type should be a gas with which
the molbloc has been calibrated (see molbloc Calibration Report) or press [SETUP], <1molbloc>,
[ENTER] to see if the gas is included in the molbloc calibration gas list (see Section 3.5.1).
•
Be sure the flow unit of measure you are using is correct. Many different types of flow units of
measure are commonly used and have similar names. Before selecting a unit of measure, familiarize
yourself with Section 3.4.3 and its subsections thoroughly.
•
Do not supply a gas or connect a DUT upstream of the molbloc that may contaminate the molbloc.
•
Troubleshooting: For information on typically encountered start-up and operational issues, see Section 6.
2.6
SHORT TERM STORAGE
The following is recommended for short term storage of molbox1:
•
Vent the molbox1 pressure ports.
•
Turn off the power.
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© 1995 - 2007 DH Instruments, a Fluke Company
MOLBOX1™ OPERATION AND MAINTENANCE MANUAL
NOTES
© 1995 - 2007 DH Instruments, a Fluke Company
Page 26
3. OPERATION
3.
OPERATION
3.1
GENERAL OPERATING PRINCIPLES
3.1.1
molbloc CHANNEL A & CHANNEL B
molbox1 supports two molbloc input channels. The main purpose of this capability is to switch
conveniently between two molblocs without making and breaking connections, for example,
to switch between two ranges. It also allows two molblocs to be used simultaneously
(see Section 3.5.4).
The active molbox1 channel is indicated by the lit LED under the display. The active channel
can be changed by pressing the [A/B] direct function key (see Section 3.4.7). When a
molbloc channel is activated, molbox1 operates internal valves to connect the molbloc
pressure ports for that channel to the molbox1 pressure transducers. The temperature of the
molbloc connected to the active channel is measured and the flow calibration data for the
molbloc most recently activated on that channel is used for calculating flow.
1.
Channel A High Isolation: Open
2.
Channel A Low Isolation: Open
3.
Channel B High Isolation: Closed
4.
Channel B Low Isolation: Closed
5.
Bypass: Closed
Figure 3. molbox1 Internal Pneumatic Schematic CHANNEL A ACTIVE, molbloc-L OPERATION
User-selected settings such as gas, units, K factor, etc. are all common between channel A
and channel B. When one of these settings is changed while channel A is active, that setting
will also be made for channel B, even if different molbloc types are connected to the two
channels. The only setting that is not common to both molbloc channels is the tare value
(See Section 3.4.4).
3.1.2
molbloc-L AND molbloc-S OPERATION
molbox1 operates somewhat differently depending on whether a molbloc-L or molbloc-S is
connected to the active molbox1 channel. mobloc-L and molbloc-S operation use different displays
and flow calculations and some menu items are present for only one type of molbloc.
Most molbox1 settings, such as gas, units, K factor, etc., are common to both molbloc-L and
molbloc-S operation. Changes made to these settings while operating one type of molbloc
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© 1995 - 2007 DH Instruments, a Fluke Company
MOLBOX1™ OPERATION AND MAINTENANCE MANUAL
will still be in effect when the other type of molbloc is connected. The only setting that exists
for both molbloc types, but is stored independently for each type, is the tare value. See
section 3.4.4.1 for details on the tare function.
Several of the molbox1 screen displays and functions described in this section are different
for molbloc-L and molbloc-S operation. Where the differences are major, the description of
these functions is divided into two parts.
3.1.3
FLOW READY/NOT READY INDICATION
The character to the left of the measured flow on the MAIN run screen provides a flow
Ready/Not Ready indication. This indication is intended to provide the user with a clear and
objective indication of when a stable flow has been achieved.
Ready <*> is indicated when the current stability (rate of change) of flow is less than the
stability limit. The user can set the stability limit (see Section 3.5.2). The Ready/Not Ready
indication is often used when comparing the molbox1 and a test device to help determine
when steady state flow conditions are present so that a valid comparison reading can be made.
3.1.3.1
molbloc-L OPERATION
In molbloc-L operation, the Ready/Not Ready indication also helps guard against
using molblocs above their valid range by monitoring the Reynolds number of the
flow. If the Reynolds number of the current flow exceeds 1 300, the Ready (<*>)
indicator flashes. The current Reynolds number value can be viewed using
[P&T] (see Section 3.4.5). If molblocs are used within the pressure and flow
range limits for the flowing gas and the pressure dependent calibration type (see
Section 1.2.5), a Reynolds number of 1 200 will never be exceeded (1 300 is
used as the warning limit to allow for individual molbloc differences).
Ready/Not Ready character indications are:
<*>
Flow Ready (stable).
<*>
(Flashing): Reynolds number > 1 300.
<↓>
Flow Not Ready (unstable and decreasing).
<↑>
Flow Not Ready (unstable increasing).
3.1.3.2
molbloc-S OPERATION
In molbloc-S operation, the Ready/Not Ready indication is also used to warn the
user when the BPR (back pressure ratio) is too high to ensure critical flow (see
Section 3.1.5). When the BPR is beyond the choking limit, molbloc-S flow
measurements may not be valid and the Ready indicator becomes <P>. The
Ready/Not Ready indicators based on flow stability are also used in molbloc-S
operation, but the <P> indicator takes priority over other indicators.
Ready/Not Ready character indications are:
<*>
Flow Ready (stable).
<↓>
Flow Not Ready (unstable and decreasing).
<↑>
Flow Not Ready (unstable increasing).
<P>
Flow Not Ready (BPR high / sub-critical flow)
© 1995 - 2007 DH Instruments, a Fluke Company
Page 28
3. OPERATION
3.1.4
REFERENCE PRESSURE TRANSDUCER (RPT)
OVERPRESSURE
molbox1 has two absolute RPTs, one measures molbloc upstream pressure, the
other measures molbloc downstream pressure and may provide a second
measurement of molbloc upstream pressure in molbloc-S operation. In normal
operation, they are not used at pressures greater than the following maximum
working pressures:
molbox1 A350K:
250 kPa absolute (36 psia)
molbox1 A700K:
600 kPa absolute (87 psia)
Exposing the molbox1 RPTs to pressures greater than the maximum operating
pressure may damage them. molbox1 has a system of warnings and alarms to
protect itself from overpressure (see Section 3.6.3.1).
3.1.5
molbloc-S BPR LIMITS
To make flow measurements within predictable measurement uncertainty limits with a molbloc-S
flow element, critical (sonic) flow conditions must be present. Critical flow exists when the
gas velocity reaches the local speed of sound at the throat of the molbloc-S Venturi nozzle.
molbox1 uses the back pressure ratio, or BPR (the ratio of the molbloc-S downstream
absolute pressure to the upstream absolute pressure) to determine whether the flow is critical.
For Venturi nozzles in general, the BPR must remain below a certain value for critical flow to
exist. Commonly accepted practice for critical flow orifice use suggests that this limiting BPR
value, or “choking ratio”, is approximately 0.5. That is, the absolute pressure downstream of
the nozzle must be less than one half of the absolute pressure upstream of the nozzle.
Empirical study of the Venturi nozzles used in molbloc-S shows that the actual choking ratio,
or maximum BPR for critical flow, varies between about 0.4 and 0.9 as a function of the
Reynolds number (Re) over which the molblocs are used. molbox1 continually calculates Re
during flow measurement and can monitor the BPR to ensure that it does not exceed the
choking ratio at the current Re conditions. molbox1 uses a conservative BPR limit to indicate
to the user when the BPR approaches the choking ratio, to ensure that flow measurements are
only made under “safe” critical flow conditions. molbox1 includes features to measure BPR,
automatically alert the operator when the BPR is too high and prevent measurements when
flow is not critical (see Sections 3.1.3.1, 3.4.4.5, 3.6.9).
Maintaining a sufficiently low BPR must be considered by molbloc-S users when selecting
molbloc-S sizes and hardware setups to use for flow measurements. For example, if a
molbloc-S will be used with atmospheric pressure downstream, then the molbloc can only be
used over a range of upstream pressures starting at the maximum pressure for its calibration
type down to a minimum pressure value at which the BPR becomes equal to the BPR limit
calculated by molbox1. Since mass flow through molbloc-S is proportional to the upstream
absolute pressure, the flow range for the molbloc in this application is defined by the BPR
limit also. To maximize the range of a molbloc-S element, a vacuum pump can be connected
downstream to reduce the downstream pressure while flowing. When the downstream
pressure is kept sufficiently low, the upstream pressure, and thus the mass flow rate, can be
adjusted all the way down to the minimum value for the molbloc’s pressure dependent
calibration type without being limited by the BPR value.
Depending on the placement of the molbloc-S in relation to the DUT and other hardware, and
the availability and capacity of a vacuum pump that may be used, the molbloc-S downstream
pressure will vary in different applications. Calculating Re for different molbloc-S sizes and
flow rates, and estimating the choking ratio (maximum BPR limit) as a function of Re is
somewhat complex, so Table 17 is offered as an example of the minimum flow that can be
achieved with each molbloc-S size in nitrogen, without exceeding molbox1 BPR limits, when
the molbloc-S downstream pressure is known: In actual operation, molbox1 calculates the
Page 29
© 1995 - 2007 DH Instruments, a Fluke Company
MOLBOX1™ OPERATION AND MAINTENANCE MANUAL
Re and BPR ratio and can automatically provide an indication of whether the BPR is adequate for
measurements to be made. For an estimate of the minimum critical flow at various downstream
pressures in gases other than N2, contact your DHI Representative.
Table 17: Minimum molbloc-S Critical Flow (slm) in nitrogen at Various molbloc-S Downstream Pressures
N2 MINIMUM molbloc-S CRITICAL FLOW [SLM @ 0°C] WITH MOLBLOC DOWNSTREAM PRESSURE OF:[1]
≤5
kPa
(0.7
psia)
molbloc-S
DESIGNATOR
10
kPa
(1.5
psia)
25
kPa
(3.5
psia)
50
kPa
(7
psia)
100
kPa
(15
psia)
110
kPa
(16
psia)
125
kPa
(18
psia)
150
kPa
(22
psia)
200
kPa
(30
psia)
250
kPa
(36
psia)
300
kPa
(44
psia)
1
[2]
1.7
3.4
4.7
1E2-S
2
[2]
3.4
5.9
8.4
15
16
18
21
27
33
38
2E2-S
4
[2]
5.9
9.8
16
28
31
34
40
51
63
74
5E2-S
10
[2]
12
20
37
67
72
80
95
122
149
179
1E3-S
20
[2]
20
[2]
39
69
129
139
154
184
239
294
349
2E3-S
40
[2]
40
[2]
73
131
248
268
298
358
468
578
687
5E3-S
100
[2]
100
[2]
173
317
596
646
746
871
1 145
1 420
1 694
1E4-S
200
[2]
200
[2]
347
615
1 173
1 273
1 442
1 741
2 240
2 789
3 338
5E1-S
7.7
8.4
9.4
11
14
17
20
[1] When volumetrically based mass flow units with reference temperatures other than 0 °C are used, flow values
will generally be higher; for example, the flow values for a given molbloc and upstream pressure are
approximately 7 % higher when expressed in slm @ 20 °C. Flow values at a given pressure may vary by up to
2 % due to flowpath machining tolerances.
[2] Limited by 20 kPa minimum calibration pressure rather than back pressure ratio.
3.2
MAIN RUN SCREEN
The molbox1 MAIN run screen is its home display that is reached on power up and from which other
functions and menus are accessed. It is the top level of all menu structures.
The MAIN run screen is displayed in normal operation. It indicates the current measured flow as well as a
variety of additional information, if desired.
The MAIN run screen display applies to the molbloc on the active molbloc channel indicated by the red
LED below the molbox1 display (A or B). The appearance of the MAIN run screen diffs depending on
whether the active molbloc is a molbloc-L or a molbloc-S.
3.2.1
molbloc-L OPERATION
Some items in the molbloc-L MAIN run screen may change or flash at times, to indicate that
certain limits are exceeded, as described in the text accompanying the following screen
display:
1.
<*> Ready/Not Ready indication; <*> when Ready (flashes if
Reynolds number of the flow exceeds 1 300), <↑>
(increasing) or <↓> (decreasing) indicating direction of flow
rate evolution when Not Ready (see Section 3.1.3).
*FLOWWWW unitk GGGG
D DISPLAY MODE DATA MFC1R
2.
<FLOWWWW>: Numerical value and sign of the flow
measured by molbox1. Result of last flow averaging cycle if
in AVERAGE display (see Section 3.4.6.2). Flashes if
Reynolds number of the flow exceeds 1 300.
3.
<UNIT>: Current flow unit of measure (see Section 3.4.3).
4.
<k>: Indication whether a gas conversion factor or ADJ flow adjustment is applied to the displayed flow
measurement. Possible indications include:
<k>: Indicates that a gas correction factor (K factor) is currently being applied to the measured flow (see
Section 3.4.1). <k> if a factor is being applied, blank if no factor is being applied.
© 1995 - 2007 DH Instruments, a Fluke Company
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3. OPERATION
<A>: Indicates that a flow adjustment adder and/or multiplier) is currently being applied to the measured flow
using the ADJ function (see Section 3.5.3). <A> if ADJ is being applied, blank if no ADJ is
being applied. Alternating When both ADJ and a K factor are applied, the indication alternates between
<k> and <A> at each screen update.
6.
<D GGGG>: Indicates the current molbox gas selection (see Section 3.4.2). This should be the gas that is
flowing through the molbloc.
6.
<D>: Indication of what is being displayed on the bottom line of the display as set by the DISPLAY function
(see Section 3.4.6). Possible indications include:
<R>:
Current DISPLAY mode is RATE (see Section 3.4.6.1); or if <n avg> is in the bottom right hand corner
of the display, current DISPLAY mode is “average” and this is the instantaneous reading AVERAGE
screen (see Section 3.4.6.2).
<σ>
Current DISPLAY mode is AVERAGE (see Section 3.4.6.2).
<H>
Current DISPLAY mode is HI/LO (see Section 3.4.6.3).
<∑>
Current DISPLAY mode is TOTAL (see Section 3.4.6.4).
<=>
Current DISPLAY mode is UNIT (see Section 3.4.6.5).
<D>
Current DISPLAY mode is DEVIATION (see Section 3.4.6.6).
<F>
Current DISPLAY mode is FREEZE (see Section 3.4.6.7).
Blank, No character
Current DISPLAY mode is CLEAN (see Section 3.4.6.8).
7.
<DISPLAY MODE DATA>:
Section 3.4.6).
Information displayed depends on current display mode (see
8.
<MFC1R>: If the molbox1 has the MFC control option, MFC profile and MFC switchbox channel number are
displayed when MFC function is on. Followed by R if MFC is in regulation mode. This display is overridden
by <DISPLAY MODE DATA> if the space is needed to display <DISPLAY MODE DATA> (Average, Hi/Lo,
Total, Unit, Deviation).
The MAIN run screen may be slightly different when MFC control is in use or an A_B
function is in use (see Sections 3.4.8, 0).
When a number is too large to show in the allocated display space, molbox1
displays <********>.
molbox1 has a SCREEN SAVER function that causes the display to dim if NO key is
pressed for 10 minutes. Pressing a key restores full power to the display. The screen
saver activation time can be changed or screen saving can be completely suppressed (see
Section 3.6.5.1).
3.2.2
molbloc-S OPERATION
As with molbloc-L there are limits on some of the conditions that may exist if the user expects
to make accurate flow measurements with molbloc-S. The key condition that can be monitored is
the back pressure ratio, or BPR, which determines whether critical flow through the molbloc is
achieved (see Section 3.1.5).
When the BPR is in a “safe” region for critical flow measurements, the appearance of the
MAIN run screen is identical to the MAIN run screen in molbloc-L operation (see Section
3.1.3.1). When the molbox1 BPR limit is exceeded, there are two possible MAIN run screen
indicators. A flashing flow value and unit indicate that the BPR limit has been exceeded. In
this condition, the flow may not be critical and flow measurements should not be relied on to
meet specifications. When the BPR limit is exceeded by a large margin, the flow is almost
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MOLBOX1™ OPERATION AND MAINTENANCE MANUAL
certainly
not
critical
and
the
calculated
value
so the flow value is not shown and is replaced by <BPR HI>.
may
be
non-sensical,
When molbloc-S is in the BPR OFF mode (see Section 3.6.9), BPR is not monitored and
invalid flow values may be displayed in the molbloc-S MAIN run screen with no indication
that a the BPR value is high.
1.
<*> Ready/Not Ready indication; <*> when Ready <↑>
(increasing) or <↓> (decreasing) indicating direction of flow
rate evolution when Not Ready; <P> when BPR is higher
than choking limit. (see Section 3.1.5).
2.
<FLOWWWW>: Numerical value and sign of the flow
measured by molbox1. Result of last flow averaging cycle if
in AVERAGE display (see Section 3.4.6.2). Flashes if BPR
is higher than the choking limit. If BPR exceeds the choking
limit by a large margin, <BPR HI> replaces the flow value.
3.
<UNIT>
4.
<k>: Indication whether a gas conversion factor or ADJ flow adjustment is applied to the displayed flow
measurement. Possible indications include:
*FLOWWWW unitk GGGG
D DISPLAY MODE DATA MFC1R
Current flow unit of measure (see Section 3.4.3). Flashes if BPR is higher than the choking limit.
<k>: Indicates that a gas correction factor (K factor) is currently being applied to the measured flow (see
Section 3.4.1). <k> if a factor is being applied, blank if no factor is being applied.
<A>: Indicates that a flow adjustment adder and/or multiplier) is currently being applied to the measured flow
using the ADJ function (see Section 3.5.3). <A> if ADJ is being applied, blank if no ADJ is
being applied. Alternating When both ADJ and a K factor are applied, the indication alternates between
<k> and <A> at each screen update.
5.
<GGGG>: Indicates the current molbox gas selection (see Section 3.4.2). This should be the gas that is
flowing through the molbloc. <AirW> indicates that air is selected and a humidity correction is being applied
(see Section 3.4.2.2).
6.
<D>: Same as molbloc-L (see Section 3.1.3.1).
7.
<DISPLAY MODE DATA>: Information displayed depends on current display mode (see Section 3.4.6).
8.
<MFC1R>: Same as molbloc-L (see Section 3.1.3.1).
The MAIN run screen may be slightly different when MFC control is in use or an A_B
function is in use (see Sections 3.4.8, 0).
When a number is too large to show in the allocated display space, molbox1
displays <********>.
molbox1 has a SCREEN SAVER function that causes the display to dim if NO key is
pressed for 10 minutes. Pressing a key restores full power to the display. The screen
saver activation time can be changed or screen saving can be completely suppressed (see
Section 3.6.5.1).
© 1995 - 2007 DH Instruments, a Fluke Company
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3. OPERATION
3.3
MANUAL OPERATION
molbox1 is designed to offer the optimum balance between simple, intuitive operation and the
availability of a wide variety of functions with a high level of operator discretion. The local
operator interface is through the front panel’s 2 x 20 character alpha-numeric display and a
4 x 4 multi-function keypad. Remote operation by RS232 or IEEE-488 interface is also
available (see Section 4).
3.3.1
KEYPAD LAYOUT AND PROTOCOL
molbox1 has a 4 x 4 keypad for local operator access to direct functions, function menus and
for data entry.
1.
The Editing and Execution keys are for
execution, suspending execution, backing up in
menus and editing entries.
2.
The Menu/Data keys provide access to function
menus from the MAIN run screen. The menu
name is on the bottom half of the key. The SETUP
menu is for more frequently used functions. The
SPECIAL menu is for less frequently used and
internal functions. These keys enter numerical
values when editing.
3.
The Function/Data keys allow very commonly
used functions to be accessed directly from the
MAIN run screen by a single keystroke. The name
of the function is on the bottom half of the key
(see Section 3.3.2). These keys enter numerical
values when editing.
Figure 4. Keypad Layout
Pressing the [ENTER] key generally causes execution or forward movement in the menu tree.
Pressing the [ESCAPE] key generally allows movement back in the menu tree and/or causes
execution to cease or suspend without changes being implemented. Pressing [ESCAPE]
repeatedly eventually returns to the MAIN run screen. From the MAIN run screen, pressing
[ESCAPE] allows momentary viewing of the molbox1 identification screen.
Pressing the [+/-] key changes a numerical sign when editing.
multiple screens when available.
It also toggles through
Pressing the [←] and [→] keys allows reverse and forward cursor movement when editing
data entry. These keys are also used to scroll through choices.
Menu selections can be made by pressing the number of the selection directly or by pressing
[←] and [→] to place the cursor on the number of the desired selection and pressing
[ENTER].
Some screens go beyond the two lines provided by the display. This is indicated by a
flashing arrow in the second line of the display. Press [←] and [→] to move the cursor to
access the lines that are NOT visible or directly enter the number of the hidden menu
choice if you know it.
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MOLBOX1™ OPERATION AND MAINTENANCE MANUAL
3.3.2
DIRECT FUNCTION KEYS SUMMARY
Local operation of molbox1 is through the front panel 4 x 4 pressure sensitive keypad. To
minimize the use of multi-layered menu structures, the keypad numerical keys also provide direct
access to the most commonly used functions. The function accessed is labeled on the bottom
half of the each key. Direct function keys are active whenever molbox1 is in its MAIN run screen.
Table 18 summarizes the operation of the direct function keys. See corresponding manual
sections for full detail on each direct function.
It may be useful to keep a copy of Table 18, Summary of molbox1 Direct Function Key
Operations, near the molbox1, especially when first becoming acquainted with its operation.
Table 18. Summary of molbox1 Direct Function Key Operations
DIRECT FUNCTION KEYS ARE ACTIVE FROM THE MAIN RUN SCREEN
SEE CORRESPONDING MANUAL SECTIONS FOR FULL DETAIL
Menu of commonly used setup features including MFC profiles, stability setting and
secondary unit changes.
Menu of less frequently used internal functions and settings including preferences, resets,
remote interfaces, BPR (back pressure ratio) when using molbloc-S.
Select active molbloc channel.
Turn on the MFC control option, select MFC profile to use and MFC switchbox channel.
Set the resolution with which the measured flow and other values are displayed.
Run the TARE, LEAK CHECK, PURGE and AutoZ functions.
Display the current pressure measurements (first press).
Display the current molbloc temperature measurements (second press).
Define the DISPLAY function for the second line of the molbox1 display. Choices include
nd
rate, average, hi/lo, totalize, 2 unit, deviation, freeze, clean.
Set/change a DUT gas correction factor (K factor).
Set flow measurement gas.
Set flow measurement unit. Choice of units can be customized.
© 1995 - 2007 DH Instruments, a Fluke Company
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3. OPERATION
3.4
DIRECT FUNCTION KEYS
3.4.1
[K]
 PURPOSE
To cause the flow value calculated by molbox1 to be multiplied by a factor, K. Generally used
to apply a test device’s gas correction factor used when a test device is calibrated with a gas
other than its normal gas.
 PRINCIPLE
Frequently, when testing or calibrating a flow measuring device, it is not possible to flow the
gas with which that device will normally be operated (the process gas). This may be
because the process gas is toxic or corrosive or simply because it is not available. When the
process gas cannot be used for calibration, it is common to use a different gas for testing or
calibrating (the calibration gas). In this case, a factor representing the relationship between
the calibration gas and the process gas for the test device may be applied so that the
calibration gas simulates the process gas. The calibration gas that simulates the
process gas is often called a surrogate gas for the process gas.
The relationship between a test device’s process gas and calibration gas is frequently
called a K factor or gas conversion factor. The factor’s value depends on specific properties
of the test device and determining the value is the responsibility of the device manufacturer.
For example, Silane (SiH4) is a frequently used gas in semiconductor processing. SiH4 is
highly toxic and requires extensive handling precautions so it is not practical for use in
calibration and testing. A major manufacturer of Mass Flow Controllers (MFCs) recommends
that MFCs that are to be used with Silane be tested with Sulfur Hexafluoride (SF6), a nontoxic, non-flammable gas, using a conversion factor of 0.970. In other words:
SF6 flow x 0.970 = equivalent SiH4 flow for the MFC
The K function in molbox1 allows a gas conversion factor to be entered by which flow values
measured by molbox1 will be multiplied. In this example, 0.970 would be entered as K so
that the values indicated by molbox1 when SF6 is flowing through the molbloc simulate the
flow of SiH4 for that manufacturer's MFC.
When the K function is active, molbox1 performs all of its flow calculations normally but
multiplies the current flow value by the value of the K factor prior to displaying it.
The gas selected on molbox1 which is displayed in the upper right corner of the molbox1
display should always be the gas that is actually flowing through the molbloc.
K factors or gas conversion factors are based on the properties of the device
being tested.
Their availability and validity are the responsibility of that
device's manufacturer. molbox/molbloc does not use factors or conversion coefficients
between gases. Flow is calculated from molbloc characteristics and specific gas
properties for each gas supported by molbox1.
The gas selected on molbox1
(see Section 3.4.2) which is displayed in the upper right corner of the molbox1 display
should always be the gas that is actually flowing through the molbloc.
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MOLBOX1™ OPERATION AND MAINTENANCE MANUAL
 OPERATION
To enable a gas conversion factor press [K] from any
run screen. The display is:
K Factor?
1on 2off
If <2off> is selected, no conversion factor will
be applied. If <1on> is selected, the next screen is:
K Factor:
1.00000
The value of the gas conversion factor can be edited as desired. Pressing [ENTER] returns
to the MAIN run screen with the entered K factor active. The letter <K> is always
appended to the flow unit indication in the run screens when the K function is ON
(e.g., sccmK). A K factor value of 1 is handled as if the K function were OFF.
When the K function is ON, as indicated by a <K> following the current flow unit in the
first line of the MAIN run screen, the current molbox1 flow indication is:
(flow as calculated by molbox1 for the selected gas) x (the current K factor)
Thus, the flow indicated is actually in error (biased) by the reciprocal of the K factor.
3.4.2 [GAS]
 PURPOSE
To specify the gas that is currently flowing through the molbloc so that molbox1 uses the
correct gas properties in its flow calculations.
 PRINCIPLE
molbox1 calculates the flow through a molbloc from:
•
molbloc geometric characteristics
•
gas pressures
•
gas temperature
•
specific characteristics of the flowing gas
The gas characteristics include:
•
gas density under standard conditions
•
change in gas density with pressure and temperature
•
gas viscosity under standard conditions (when needed)
•
changes in gas viscosity with pressure and temperature
Proprietary algorithms are used to calculate gas density and viscosity (when needed) under
the actual flowing pressure and temperature conditions from density and viscosity under
standard conditions.
The characteristics of molbox1 supported gases and corresponding algorithms are stored in
molbox1 memory. To correctly calculate the flow of a gas, the correct information for that gas
must be used. The molbox1 GAS function allows the user to specify the flowing gas so that
molbox1 will use the correct gas information in calculating the flow through the molbloc.
© 1995 - 2007 DH Instruments, a Fluke Company
Page 36
3. OPERATION
The set of available calibration gases that can be used is not the same with molbloc-L and
molbloc-S, and the operation of the GAS function, is different. They are described separately below.
3.4.2.1
molbloc-L OPERATION
The molbox1 gases available for use with molbloc-L at the time of this manual
printing are listed in Table 19.
Table 19. Available molbloc-L Gases
<1inert>
<2flammable>
<3toxic>
<4other>
<1N2> Nitrogen
<1H2>
Hydrogen
<1Air>
Air
<2He> Helium
<2O2>
Oxygen
<1CO> Carbon Monoxide
<2C2F6>
Hexafluoroethane
<3Ar> Argon
<3CH4>
Methane
<3N2O>
Nitrous Oxide
<4C2H4> Ethylene
<4CF4>
Carbon Tetrafluoride
<5C3H8> Propane
<5SF6>
Sulfur Hexafluoride
<6C2H6> Ethane
<6CHF3> Fluoroform
<7Butn>
<7C02>
Carbon Dioxide
<8Xe>
Xenon
<9C4F8>
Octofluorocyclobutane
Butane
<Butn> is used to identify Butane in molbox1 because the chemical symbol
for Butane (C4H10) has more than the 4 characters used by molbox1 to
abbreviate gas identifications.
Mixtures of known gases in known concentrations can be measured by
calculation and use of the ADJ function (see Section 3.5.3).
 OPERATION (molbloc-L operation)
To specify the gas flowing through
molbloc-L, press [GAS]. The display is:
1inert 2flammable
3toxic 4other
The gases available are grouped in
categories to facilitate finding a specific
gas and as a reminder to the user when
selecting a gas that may require special
precautions in use. There is a list of gases
under each category. For example, the
<1inert> selection displays:
1N2
2He
3Ar
Select the desired gas. Pressing [ENTER] returns to the last run screen with
the selected gas active. The selected gas is always displayed in the upper right
hand corner of the MAIN run screen.
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MOLBOX1™ OPERATION AND MAINTENANCE MANUAL
The gas selected on the molbox1 should always be the gas that is flowing
through the molbloc. molbloc/molbox does not use K factors or gas
conversion factors between gases. When calibrating or testing a device with
a surrogate gas, molbox1 should be set to the surrogate gas. The K factor
or gas conversion factor, if used, defines the relationship between the
surrogate gas and the process gas for the device being tested, not for
molbox1 (see Section 3.4.1, PRINCIPLE). The K factor is supplied by the
manufacturer of the device being tested.
3.4.2.2
molbloc-S OPERATION
The molbox1 gases available for use with molbloc-S at the time of this manual
printing are listed in Table 20.
Table 20. Available molbloc-S Gases
<1inert>
<2flammable>
<3toxic>
<1CO> Carbon Monoxide
<4other>
<1N2> Nitrogen
<1H2>
Hydrogen
<2He> Helium
<2O2>
Oxygen
<3N2O>
<1Air>
Air
Nitrous Oxide
<3Ar> Argon
<3CH4>
Methane
<5SF6>
Sulfur Hexafluoride
<7C02>
Carbon Dioxide
Normally, selecting a gas with one molbloc type connected (molbloc-L or
molbloc-S) also makes that gas the selected gas for the opposite molbloc type
the next time it is used. However, when a gas is selected for use with molbloc-L
that is not supported for molbloc-S use, the molbox1 gas will change to N2 when
a molbloc-S is connected.
In addition to dry air, molbox1 supports measurement of ambient (humid) air flow
with molbloc-S. When Air is selected as the molbloc-S test gas, the user is
prompted to enter a value of the humidity ratio (also known as the absolute
humidity or water ratio) of the ambient air. The humidity ratio, W, is defined as
the ratio of water mass to gas mass in the flowing air. It is different from the
relative humidity value, which is usually expressed as a percentage. Typical values
of W are between zero and 0.06. molbox1 does not accept an entry for W
greater than 0.1.
Typically, humidity measuring instruments report relative humidity, which is
dependent on the ambient pressure and temperature. Users who do not have
the W value available can use DHI’s free Unit of Measure Converter software
utility or COMPASS for molbox calibration software to calculate W from measured
pressure, temperature, and relative humidity. Visit www.dhinstruments.com, or see
your DHI sales representative for a copy of the Unit of Measure Converter
software utility. Air relative humidity, pressure and temperature are converted to
the humidity ratio, W, following Dalton’s Rule and thermodynamic principals
using water saturation properties:
⎛ RH ⎞
Pg ⋅ ⎜
⎟
100 ⎠
⎝
W = .62188 ⋅
⎛ RH ⎞
Pamb − Pg ⋅ ⎜
⎟
⎝ 100 ⎠
© 1995 - 2007 DH Instruments, a Fluke Company
Page 38
3. OPERATION
Pg is the water saturation pressure, which can be calculated as:
Pg = C 0Tamb + C1Tamb + C 2Tamb + C 3
3
2
where :
C 0 = 0.0649289
C1 = −53.0528
C 2 = 14509.9
C 3 = −1327760
If dry air will be measured, then the user should enter a W value of zero when
prompted. Zero is the default W value.
When a non-zero W value is entered, molbox applies a correction to its air flow
measurement for the change in air density due to humidity. If a correction for W
is being applied to air flow measurements, a <W> is placed to the right of the
<Air> gas indication in the MAIN run screen.
The humid air correction applied to the molbloc measured flow is (from ASME
FEDSM98-5309):
qm(ratio) = a + bW + cW 2 + dW 3
where :
a = 1.0000
b = −0.336872
c = 0.158514
d = 0.131924
If an incorrect value of W is entered (for example, using any non-zero W value
while flowing dry air), an error will be introduced into the air flow
measurement. W, humidity ratio, is different from relative humidity.

OPERATION (molbloc-S operation)
To specify the gas flowing through
molbloc-L, press [GAS]. The display is:
1inert 2flammable
3toxic 4other
The gases available are grouped in
categories to facilitate finding a specific
gas and as a reminder to the user
when selecting a gas that may require
special precautions in use. There is a
list of gases under each category. For
example, the <4other> selection
displays:
1Air
4CO2
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2N2O
3SF6
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MOLBOX1™ OPERATION AND MAINTENANCE MANUAL
Select the desired gas. If <2Air> is selected,
Humidity ratio:
0:1
The display is:
Leave the value at zero when dry air is being flowed. Enter the appropriate nonzero value (see section immediately above) if humid air is being flowed.
Pressing [ENTER] returns to the last run screen with the selected gas active.
The selected gas is always displayed in the upper right hand corner of the MAIN
run screen.
The gas selected on the molbox1 should always be the gas that is flowing
through the molbloc. molbloc/molbox does not use K factors or gas
conversion factors between gases. When calibrating or testing a device with
a surrogate gas, molbox1 should be set to the surrogate gas. The K factor
or gas conversion factor, if used, defines the relationship between the
surrogate gas and the process gas for the device being tested, not for
molbox1 (see Section 3.4.1, PRINCIPLE). The K factor is supplied by the
manufacturer of the device being tested.
3.4.3
[UNIT]
 PURPOSE
To specify the flow unit of measure in which molbox1 displays measured flow values.
 PRINCIPLE
molbox1 calculates the mass flow of various gases in kilograms/second [kg/s]. molbox1 also
supports conversions to a variety of other flow units of measure. The UNIT function allows
the flow unit of measure in which molbox1 displays measured flow to be selected. These include
units of mass flow, including volumetrically based mass flow units (i.e., sccm) as well as units
of volume flow (i.e., ccm). See Table 21 for a complete listing of the unit conversions
available. molbox1 can also display the measured flow in two different units of measure
simultaneously (see Section 3.4.6.5).
 OPERATION
If the molbox1 is equipped with the optional MFC control function (see Section 3.4.8), the unit of
measure for the molbox1 flow display may be defined by the currently selected MFC profile. In that
case, the [UNIT] function key is used to select the MFC output display unit (see Section 3.4.8.3).
If an MFC profile other than profile #1 or #2 is active, the unit of measure is the unit of measure
selected in the MFC profile. If the MFC control function is not present, or is turned OFF, or MFC
profile #1 or #2 is selected, the [UNIT] function key allows direct selection of molbox1 flow
display units as described below.
From the main run screen, press [UNIT]:
1sccm 2slm 3uccm
4pccm 5mg/s 6vlm
The display is:
Select the desired unit. For all units except <uxxx> or <vlm>, operation then returns to the run
screen with the flow unit of measure changed to the selected unit. When user units (i.e., uxxx)
are selected, the reference temperature must be specified before the unit is activated (see
Section 3.4.3.3). When “vlm” (volume) units are selected, a menu of volume units is
© 1995 - 2007 DH Instruments, a Fluke Company
Page 40
3. OPERATION
accessed. The desired volume unit must be selected and then the temperature and pressure
of the flowing gas must be specified (see Section 3.4.3.4).
If the MFC Control option is active and the MFC profile selected is NOT #1 or #2
(see Section 3.4.8), the molbox1 flow unit is automatically the unit specified in the
current MFC profile (see Section 3.4.8 and 3.5.5) and the UNIT function controls the unit
used for displays of MFC set and measure values.
See Section 7.1.3 for specific molbox1 flow unit conversion calculations.
molbox1 supports many more flow units of measure than the six default units of the
UNIT function. The six units available under the UNIT function can be customized to
include any molbox1 supported units in any order (see Section 3.5.8).
Many different types of flow units are commonly used including a wide variety of mass
flow units as well as volume flow units. Please read Sections 3.4.3.1 through 3.4.3.4 for
additional information on the various unit definitions and how they are handled by
molbox1 before making unit of measure selections.
3.4.3.1
MASS FLOW VS. VOLUME FLOW
COMPASS for molbox software users: conversions to volume (sometimes
called actual) flow units are handled in COMPASS. When using COMPASS,
the molbox always operates in mass flow units.
molbox1 measures mass flow (quantity of material per quantity of time).
molbox1 always calculates flow in terms of kg/second [kg/s]. It also supports
conversions of kg/second to a variety of other flow units. These include other
mass flow units such as g/s and mole/s as well as volumetrically based mass
flow units (i.e., sccm and slm) (see Section 3.4.3.2). In steady state flow, mass
flow is the same at different points in the flow system independent of gas
pressure and temperature. Therefore, the measurement of mass flow made by
the molbloc/molbox represents the mass flow at the same time at other points in
a steady state flow system.
molbox1 can also make conversions to volume flow under specific pressure and
temperature conditions by dividing the mass flow by the density of the gas under
the specific pressure and temperature conditions (see Section 3.4.3.4).
Volume flow is sometimes referred to as actual flow.
Volume flow is dependent on the actual temperature and pressure of the
flowing gas at the point where volume flow is to be measured. Generally,
this point is not at the molbloc, it is at another point in the flow system (e.g., at the DUT).
At another point in the flow system, it is quite likely that the gas pressure and
temperature are different from the gas pressure and temperature at the molbloc.
Then, even in steady state flow conditions, the volume flow at the molbloc and
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MOLBOX1™ OPERATION AND MAINTENANCE MANUAL
the volume flow at another point in the system are likely to be different.
Therefore, to accurately predict volume flow at another point in the system,
molbox1 must calculate volume flow based on the gas pressure and
temperature at that other point, not at the molbloc. For this reason, molbox1
requires that gas pressure and temperature conditions at the DUT be specified
for volume flow measurements.
Estimating the flowing gas pressure and temperature at the point at which
volume flow is to be measured may be difficult.
The relevant gas pressure when measuring volume flow is the gas’s absolute pressure.
In cases in which the volume flow measurement is open to atmospheric (ambient)
pressure, the volume flow pressure is atmospheric pressure. In other cases, there may
be ways to estimate the pressure at the volume flow measurement point but it
probably should be measured.
For temperature, if the volume flow measurement point is very near the molbloc,
one possibility is to use the molbloc temperature measurement. By design, the
molbloc causes the temperature of the gas that flows through the molbloc to take
on the molbloc temperature. Therefore, the temperature of the gas as it exits the
molbloc is the same as the molbloc temperature. If the volume flow measurement
point is not immediately downstream of the molbloc, the best estimate of gas
temperature is probably ambient temperature or the temperature of the device or
bath used to stabilize gas temperature if one is present.
Because volume flow (sometimes called actual flow) is dependent on gas
pressure and temperature at the flow measurement point, gas pressure and
temperature must be specified by the user when selecting volume flow units
on molbox1. The measurement uncertainty (accuracy) in the volume flow
measurement is highly dependent on the measurement uncertainty in the
pressure and temperature specified. Typically, temperature errors have an
effect on flow of about 0.35 %/°C and pressure errors have an effect on flow
of about 1%/kPa (6.8%/psi) if the DUT is used near atmospheric pressure.
3.4.3.2
VOLUMETRICALLY BASED MASS FLOW UNITS
molbox1 supports a number of volumetrically based mass flow units of measure.
Volumetrically based mass flow units should not be confused with volume or
actual flow units (see Section 3.4.3.4). Volumetrically based mass flow units
define mass in terms of the quantity of gas that occupies a volume under
standard conditions of pressure and temperature. Since there is no universally
accepted definition of standard conditions, molbox1 supports the three most
common variances.
•
Standard units (sxxx): The “s” prefix indicates standard. Volumetrically
based mass flow units preceded with the letter “s” (i.e., sccm, slm, scfh)
define standard conditions as pressure of 101.325 kPa absolute (14.6959
psia) and temperature of 0 °C (32 °F) and take into account the true
compressibility of the flowed gas.
•
User units (uxxx): The u prefix indicates user. This option is designed to
provide support for volumetrically based mass flow units with a reference
temperature other than 0 °C (see Section 3.4.3.3). Volumetrically based
mass flow units preceded with the letter “u” (i.e., uccm, ulm) define standard
conditions as pressure of 101.325 kPa (14.6959 psia) with the user
specifying the reference temperature. User units take into account the true
compressibility of the flowed gas.
© 1995 - 2007 DH Instruments, a Fluke Company
Page 42
3. OPERATION
•
Perfect units (pxxx): The “p” prefix indicates perfect. This option is
designed to provide support for volumetrically based mass flow units that
assume ideal gas compressibility for all gases. Volumetrically based mass
flow units preceded with the letter “p” (i.e., pccm, plm) assume a gas
compressibility factor of 1 for all gases and define standard conditions as
pressure of 101.325 kPa (14.6959 psia) and temperature of 0 °C (32 °F).
Volumetrically based mass flow units at reference temperatures other than
0 °C (32 °F) can be defined using user units (see Section 3.4.3.3).
In early 1996, SEMI (a semiconductor industry interest group) adopted
standard E12-96 which specifies that perfect units be used for
volumetrically based mass flow units. To comply with the SEMI standard,
pccm should be used rather than sccm. To purchase a copy of the relevant
SEMI standard, contact SEMI at telephone 415.964.5111 or email
[email protected].
3.4.3.3
VOLUMETRICALLY BASED MASS FLOW UNITS AT
VARIOUS REFERENCE TEMPERATURES (UXXX)
Units starting with the letter “u” (user units) are volumetrically based mass flow units
(see Section 3.4.3.2) for which a reference temperature other than 0 °C is desired.
When a user unit is selected, the reference
temperature desired must be specified.
After a user unit is selected, the display is:
Temperature ref?
0ºC
Enter the reference temperature desired for the volumetrically based mass flow
unit selected. The temperature unit can be changed between °C and °F by pressing
[SETUP] and selecting <9tempU> (see Section 3.5.9). The temperature selected
applies to all the user units.
Volumetrically based mass flow units, including user units (uxxx) and perfect
units (pxxx), are discussed further in Section 3.4.3.2.
3.4.3.4
VOLUME FLOW UNITS (VLM)
See Section 3.4.3.1 before using volume flow units. Volume flow is sometimes
referred to as actual flow.
To measure flow in volume flow units (sometimes referred to as actual flow
units), press [UNIT], <vlm> under the UNIT function. If <vlm> is not available,
see Section 3.4.3.5. This selection accesses the menu of volume units available.
Select the desired volume flow unit:
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MOLBOX1™ OPERATION AND MAINTENANCE MANUAL
1.
Current volume flow pressure.
2.
Current volume flow temperature. Indicates
<bloc> if the current setting is to use the
molbloc temperature.
P:100.325 kPa T:20.1ºC
Edit P&T? 1No 2Yes
To retain the current volume flow pressure and temperature, select <1no> and
operation returns to the MAIN run screen with the selected volume flow unit
active. To change the volume flow pressure and/or temperature select <2yes>.
The next screen gives the choice of
having the volume flow gas temperature
be either the molbloc temperature or a
user specified temperature. If <2user> is
selected, a screen to enter the temperature is
presented before continuing. If <1molbloc>
is selected, the volume flow temperature
will automatically be taken as the
molbloc temperature.
Gas temperature:
1molbloc 2user
The next screen is to edit the volume
flow pressure in the current pressure unit
of measure. Pressing [ENTER] accepts
the edited value as the volume flow
pressure and returns to the MAIN run
screen with the selected volume flow unit
and gas temperature and pressure active.
Volume unit gas pres
101.325 kPa
The temperature and pressure units of measure used to specify volume flow
conditions can be changed using [SETUP], <8presU> for pressure (see
Section 3.5.8) and [SETUP], <9tempU> for temperature (see Section 3.5.9).
Because volume flow is dependent on gas pressure and temperature at the
flow measurement point, gas pressure and temperature must be specified by
the user when selecting volume flow units. The measurement uncertainty in
the volume flow measurement is highly dependent on the measurement
uncertainty in the pressure and temperature specified (see Section 3.4.3.1).
3.4.3.5
CUSTOMIZING FLOW UNITS AVAILABLE UNDER THE
UNIT FUNCTION
The UNIT function provides a choice of six different flow units of measure. The units
that are available by default are the six indicated in Section 3.4.3. However,
molbox1 supports many other units. These other units can be made available for
selection by customizing the UNIT function.
To customize the UNIT function,
press [SETUP] and select <7flowU>.
The display is:
<#1> corresponds to the first of the six
available selections under the UNIT
function.
Enter the number of the
selection that you would like to change.
The display becomes:
© 1995 - 2007 DH Instruments, a Fluke Company
Page 44
Set up user unit #1
Flow unit type: 1std
2user 3perfect 4vlm
3. OPERATION
Select the flow unit type of the desired flow unit (see Table 21). Then select the
desired unit.
Table 21. Available Flow Units
<1std>
<2user>
<3perfect>
<1mol/s>
<2kg/s>
<3mg/s>
<4slm>
<5sccm>
<6scfm>
<7scfh>
<8slh>
<9sm3h>
<1ulm>
<2uccm>
<3ucfm>
<4ucfh>
<5um3h>
<1plm>
<2pccm>
<3pcfm>
<4pcfh>
<5plh>
<6pm3h>
<4vlm>
<1ccm>
<2lm>
<3lh>
<4m3h>
<6cfm>
<7cfh>
The <4vlm> unit selection embeds the selection “vlm” into the UNIT function
rather than a specific volume unit. The “vlm” selection provides access to all
the volume flow units. In summary the unit types are:
<1std> (standard):
mass flow units for which “standard” conditions are
temperature of 0 °C, standard atmosphere and using
the true compressibility factor of the gas.
<2user>:
mass flow units for which “standard” conditions are a
user settable temperature, standard atmosphere and
using the true compressibility factor of the gas.
<3perfect>:
mass flow units for which “standard” conditions are
temperature of 0 °C, standard atmosphere and
assuming a compressibility factor of 1 for all gases.
<4vlm>:
volume flow units.
See Sections 3.4.3.1 to 3.4.3.4 for additional information on flow unit types.
3.4.4 [TARE]
 PURPOSE
[TARE] accesses five functions.
•
TARE function: To zero the molbox1 differential pressure readings in molbloc-L
operation or verify the two RPTs by comparing them against each other in molbloc-S
mode (see Section 3.4.4.1).
•
PURGE function: To purge the molbloc connecting lines and molbox1 internal volume of a
first gas with a second gas by flowing the second gas through the molbox1 (see Section 3.4.4.2).
•
LEAK CHECK function: To check the molbox1 internal pneumatic circuit and/or the
external test circuit to which molbox1 is connected, for leaks (see Section 3.4.4.3).
•
AUTOZ function: To periodically offset the molbox1 RPTs relative to a reference
pressure value in order to compensate for possible changes in the RPT zero between full
recalibrations (see Section 3.4.4.4).
•
BPR function (present only in molbloc-S operation): To measure and display the
molbloc-S back pressure ratio (BPR) while operating in a BPR mode which does not
continuously read and display BPR (see Section 3.4.4.5).
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MOLBOX1™ OPERATION AND MAINTENANCE MANUAL
 OPERATION
Pressing [TARE] accesses a display with the choice
of four functions (five functions in molbloc-S
operation). Select the desired function. See the
following for principles and operation:
1tare 2purge
3leak check 4AutoZ ↓
5BPR
Some screens (e.g., the Tare menu) may go beyond the two lines provided by the display.
This is indicated by a flashing arrow in the second line of the display. Press the [←] and
[→] keys to move the cursor to access the lines that are NOT visible or directly enter the
number of the hidden menu choice if you know it.
3.4.4.1
<1Tare>
The purpose and operation of the tare function is different for molbloc-L and
molbloc-S operation. It is described separately for the two modes below.
3.4.4.1.1

molbloc-L Operation
PURPOSE
To zero the molbox1 at the molbloc operating pressure. Zeros the differential
reading between the two reference pressure transducers.

PRINCIPLE
The molbox1 TARE function can be considered the equivalent of the zeroing
function performed on many instruments prior to making measurements.
molbox1 calculates the flow through a molbloc-L from the differential pressure
across the molbloc. The differential pressure across the molbloc is measured by
taking the difference in the absolute pressure measured by the molbox1’s two
internal RPTs. One RPT is connected to the upstream molbloc pressure port
and the other to the downstream molbloc pressure port.
If a common pressure is applied to both RPTs the differential pressure indicated
should be zero. If a differential pressure value is observed, the value indicated
represents an offset in the differential measurement which will appear as an
offset or “zero error” on the flow through molbloc-L calculated by the molbox1.
The TARE function allows the differential indication between the two RPTs to be
zeroed at the molbloc operating pressure to eliminate the zero error in differential
pressure measurement.
When the TARE function is activated, molbox1’s internal valves operate to
pneumatically connect together the two absolute transducers at the molbloc
operating pressure (see Figure 5). The user can select whether this pressure is
the upstream or downstream molbloc pressure so that the tare can be made at
the pressure that will be held stable during operation (generally by a regulator or
because it is open to atmosphere). Activating the tare causes molbox1 to record
the current differential as the tare value. The tare value is then used to correct all
subsequent RPT readings. The tare value is the difference between the two
transducer readings (hi - lo). After taring, the upstream RPT is corrected by
(- tare value/2) and the downstream RPT is corrected by (+ tare value/2).
© 1995 - 2007 DH Instruments, a Fluke Company
Page 46
3. OPERATION
1.
Channel A High Isolation: Open
2.
Channel A Low Isolation: Closed
3.
Channel B High Isolation: Closed
4.
Channel B Low Isolation: Closed
5.
Bypass: Open
Figure 5. molbox1
Internal Pneumatic Schematic – TARING CHANNEL A, UPSTREAM
molbloc-L OPERATION

OPERATION
At a minimum, the TARE function should be executed whenever the operating
pressure of the molbloc is changed significantly, at the beginning of each
test or any time a significant zero error is observed. For best results, it is
possible to tare before every reading since taring can be executed while
flowing. Best results will be obtained if the TARE function is executed with a
stable flow through the molbloc.
If the molbox1 is in A+B or A/B mode, the channel for which to tare must be
specified before taring.
To access the TARE function press [TARE], <1tare>.
Select tare pressure:
1upstream 2dnstream
The display is:
Selecting <1upstream> will tare the molbox1 RPTs at the molbloc’s
upstream pressure (see Figure 5). Selecting <2dnstream> will tare the RPTs at
the molbloc’s downstream pressure (Low isolation valve open, High isolation
valve closed). Select the position where the pressure will remain the most stable
during molbloc operation.
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The next display is:
1.
The current pressure read by the upstream
(left) and downstream (right) RPTs without
taking into account the current tare value.
These are untared readings in the current
pressure units.
2.
<T>, flashing, to indicate that this is a TARE
display showing the tare between the two
absolute RPTs.
3.
The difference between the untared upstream
and downstream absolute pressure readings
(upstream – downstream). This differential
value is always in Pascal [Pa].
4.
The flow corresponding to the current untared
differential pressure in the current flow units.
202.347 kPaa 202.311
T
36 Pa 0.06 sccm
This display allows the current untared absolute pressures and the resulting untared
differential pressure from the difference of the two absolute RPTs to be observed.
The flow value represents the current untared zero error in terms of flow. It does
not necessarily represent the current zero error on flow measurements as a tare
value other than zero is probably already active.
Press [ENTER] when ready. molbox1 makes measurements to determine a new
tare value. The next display is:
1.
The tare value currently in use [Pa].
2.
The new tare value, resulting from this
execution of the TARE function [Pa].
OldT:
NewT:
44Pa
36Pa
Press [ENTER] to activate the new tare and return to the MAIN run screen.
Press [ESCAPE] to return to the [TARE] display without activating the new tare,
leaving the old tare active.
The tare screen shows the upstream and downstream RPT readings
WITHOUT the current tare applied. The [P&T] screen shows the RPT readings
WITH the tare applied (see Section 3.4.5).
Limits and Errors
Excessively large tare values can diagnose molbox1 RPT malfunction, the need
to recalibrate or possible poor execution of the TARE function. To protect against
improper taring and to alert to possible RPT malfunction, molbox1 checks the
tare value before it is activated and displays warnings when appropriate. In the
most extreme case, molbox1 will not allow the tare value to be activated. The limits
checked and their consequences are as follows:
© 1995 - 2007 DH Instruments, a Fluke Company
Page 48
3. OPERATION
RPT coherence test: When attempting to activate a new tare, molbox1 checks the
coherence between the two transducers and alerts the operator to excessive
disagreements. The test has two levels.
•
If the new tare is 200 Pa < tare < 3 000 Pa, a caution message is displayed.
Pressing [ENTER] overrides the caution and activates the new tare.
Pressing [ESCAPE] returns to the TARE screen.
•
If the new tare is > 3 000 Pa, the new tare cannot be activated.
Pressing [ENTER] or [ESCAPE] returns to the tare screen and retains the
old tare. It is likely that molbox1 needs service or a grossly incorrect
adjustment has been made to one or both of the RPTs.
If a caution message appears or a tare cannot be activated during the taring
process, repeat the taring process. If the caution persists, the calibration
of the RPT(s) should be verified (see Section 5.2). If the tare still cannot be
activated, the RPT(s) should be recalibrated and molbox1 may require other service.
3.4.4.1.2

molbloc-S operation
PURPOSE
To check the molbox1 RPT absolute pressure readings by comparing them at a
common molbloc-S upstream absolute pressure.

PRINCIPAL
When measuring the flow through molbloc-S, the critical pressure measured by
molbox1 is the molbloc upstream pressure. The downstream pressure is only
monitored to be sure that critical flow conditions exist (see Section 3.1.5). To reduce
the uncertainty on the upstream pressure measurement, molbox1 employs
internal valving to direct the upstream pressure to both RPTs, and the average of
the two readings is used as the measured molbloc upstream pressure. To take
advantage of this RPT averaging, the molbox1 must be in either BPR OFF or
Auto BPR mode (see Section 3.6.9).
molbox1 dynamically tares the two RPT readings when they are connected together,
so the user can view the “live” average pressure that is calculated and to allow
smooth pressure and flow measurements during valve transitions in the Auto BPR
mode (see Section 3.6.9). RPT taring in molbloc-S operation occurs automatically
when needed and does not need to be initiated or performed by the user.
The molbloc-S TARE function is available to allow the user to conveniently verify
that the two RPT measurements agree within an acceptable tolerance when a
common pressure is applied to them. When the TARE function is selected, the
molbox1 internal valves operate to connect both Q-RPTs the active channel
UPSTREAM pressure port (see Figure 6). The RPT readings and the difference
between the two RPT readings (tare value) is displayed for evaluation by the user.
A message is also displayed in to indicate to the user whether the tare value is
acceptable, or indicates a need for pressure verification or calibration of the RPTs.
There is no need for the customer to save a new tare value in molbloc-S operation.
As in molbloc-L operation, the molbloc-S tare value is the difference between the
two transducer readings (hi - lo). In BPR modes where the tare value is
dynamically calculated and applied, the upstream RPT is corrected by
(- tare value/2) and the downstream RPT is corrected by (+ tare value/2).
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MOLBOX1™ OPERATION AND MAINTENANCE MANUAL
1.
Channel A High Isolation: Open
2.
Channel A Low Isolation: Closed
3.
Channel B High Isolation: Closed
4.
Channel B Low Isolation: Closed
5.
Bypass: Open
Figure 6. molbox1
Internal Pneumatic Schematic – TARING CHANNEL A,
molbloc-S OPERATION

OPERATION
To access the TARE function press [TARE], <1tare>. The display is:
1.
The current pressure read by the upstream
(left) and downstream (right) RPTs without
taking into account the current tare value.
These are untared readings in the current
pressure units.
2.
<T>, to indicate that this is a TARE display
showing the tare between the two absolute
RPTs.
3.
The difference between the untared upstream
and downstream absolute pressure readings
(upstream – downstream). This differential
value is always in Pascal [Pa].
4.
Tare message
201.032 KpA ^201.013
T 19.3Pa
OK
For molbox1 A350K:
<OK> If tare is less than 50 Pa,
<CHECK> if tare is between 50 and 200 Pa
<NEED CAL> if tare is greater than 200 Pa
For molbox1 A700K:
<OK> If tare is less than 120 Pa,
<CHECK> if tare is between 120 and 500 Pa
<NEED CAL> if tare is greater than 500 kPa
The tare screen shows the upstream and downstream RPT readings
WITHOUT the current tare applied. The [P&T] screen shows the RPT readings
WITH the tare applied (see Section 3.4.5).
3.4.4.2

<2Purge>
PURPOSE
To purge the lines between the molbloc and the molbox1 and the internal
molbox1 volumes of one gas with another gas by setting up a molbox1 valving
configuration in which gas flows through the molbox1.
© 1995 - 2007 DH Instruments, a Fluke Company
Page 50
3. OPERATION

PRINCIPAL
molbox1 supports the measurement of flow of a variety of gases. To calculate
the flow, the thermodynamic characteristics of the gas must be known.
These are stored in molbox1 memory. For the flow to be calculated correctly, the
gas flowing through the molbloc must be the gas that is selected on the molbox1
(see Section 3.4.2). When switching from the measurement of one gas to
another, the old gas remaining in the circuit and the new gas being flowed may
mix for some time so that the gas flowing through the molbloc is not purely the
new gas. Erroneous measurements may result. For this reason, it is important
to purge the lines upstream and downstream of the molbloc when changing
gases. It is also important to purge the molbox1 itself which, since there is
normally no flow through it, may trap and hold the old gas.
The PURGE function is designed to facilitate purging the molbox1. It sets up the
molbox1 internal valving so that flow can pass through the molbox1 (see Figure 7).
In this configuration, the lines between the molbloc and molbox1 and the
molbox1 internal volume can be purged by simply flowing the new gas in the
normal flowing configuration. The flow resistance through the molbloc creates a
differential pressure which causes flow through the molbox1 to occur, purging the
molbox1 with the new gas.
1.
Channel A High Isolation: Open
2.
Channel A Low Isolation: Open
3.
Channel B High Isolation: Closed
4.
Channel B Low Isolation: Closed
5.
Bypass: Open
Figure 7. molbox1
Internal Pneumatic Schematic – PURGING CHANNEL A

OPERATION
For best results, the PURGE function should be executed whenever the
species of the gas flowing through the molbloc is changed. Prior to
activating the PURGE function, set flow through the molbloc to the highest
rate that is practical. Then, with the gas flowing, activate the PURGE
function. Very small volumes of gas remain trapped (deadended) in the
molbox1 in the PURGE configuration. Therefore, it may be desirable to
execute the PURGE function more than once to clear these volumes by the
pressure changes caused by PURGE execution.
To access the PURGE function press
[TARE], <2purge>. The display is:
Page 51
Set purge time:
15 sec
© 1995 - 2007 DH Instruments, a Fluke Company
MOLBOX1™ OPERATION AND MAINTENANCE MANUAL
The purge time can be edited. Pressing [ENTER] causes molbox1 to set its internal
valving to the purge configuration (see Figure 7) and go to the PURGE display:
1.
The current pressure read by the upstream
(left) and downstream (right) RPTs in the
current pressure unit of measure.
2.
<PURGING> to indicate that this is a PURGE
display.
3.
Countdown
seconds.
of
purge
time
remaining
202.347 kPaa 202.311
PURGING
15 sec
in
molbox1 remains in the purge condition until the purge time countdown elapses.
It then automatically returns to normal operation. When the countdown elapses
operation returns to the run screen from which PURGE was accessed.
To interrupt the PURGE function, press [ESCAPE].
The appropriate purge time setting is dependent on the flow rate and the
volumes upstream and downstream of the molbloc. Typically, 15 to 30
seconds is adequate. The time needed increases as flow rates go down and
volumes go up.
When using the PURGE function, remember that the molbox1 absolute RPTs
are exposed to the pressure. Do not apply pressure greater than 500 kPa
(80 psi).
If the molbox1 is in A+B or A/B mode, the PURGE function executes for the
specified purge time for channel A and then repeats the purge sequence for
channel B.
3.4.4.3

<3Leak Check>
PURPOSE
To access the molbox LEAK CHECK and SYSTEM LEAK CHECK functions
which use molbox1’s pressure and flow measurement capabilities to check
molbox1 and/or the system to which it is connected for leaks.

PRINCIPAL
molbox1 is used both as a tool to accurately measure unknown flow values and
as a calibration standard to calibrate other devices by comparison. Leaks within
the molbox1 pneumatic circuit can cause erroneous flow measurements. Leaks in
the external flow circuit can cause the flow through the molbloc to be different
from the flow at another point in the system so that, even with an accurate
measurement and steady state flow, the molbox1 indication is not an accurate
indication of flow at the other point in the system.
To obtain valid measurement results, it is important that leaks in molbox1 and/or
the external flow system be identified and eliminated to the extent possible.
molbox1 uses its precision on-board pressure and flow measurement capabilities
to help identify leaks with INTERNAL and EXTERNAL LEAK TESTING functions.
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3. OPERATION

OPERATION
Press [TARE] and select <3leak check> to access the LEAK CHECK functions.
Then select <1molbox> or <2system>.
<1molbox> is designed to leak check the internal molbox1 pneumatic circuit.
<2system> is designed to leak check the system to which the molbloc/molbox
is connected.
If the molbox1 is in A+B or A/B mode, the molbloc channel (A or B) to leak
check must be specified prior to running the leak check.
Leak Check molbox

PURPOSE
To check the internal molbox1 pneumatic circuit for leaks.

PRINCIPAL
It is normally not necessary to run the MOLBOX LEAK CHECK procedure frequently.
It is intended for troubleshooting purposes when there appears to be a leak or
other molbox1 measurement problem whose source cannot be identified by the
SYSTEM LEAK CHECK or other troubleshooting means. It is recommended to run
the MOLBOX LEAK CHECK after it has been shipped or if it is suspected that the
molbox has been exposed to a large shock or liquid or particulate contamination.

OPERATION
Press [TARE] and select <3leak check>, <1molbox>. The next display is:
1.
The pressure read by the upstream
transducer (left), the downstream transducer
(right) and the pressure unit of measure
(middle).
2.
Indicator that the figure that follows is
differential pressure.
3.
Differential pressure across the molbloc in
current pressure unit of measure.
4.
Prompt for the action to take when ready.
347.458 kPaa 307.455
DP
40.003 <ENTER>
The molbox1 internal valving is in its normal measuring configuration (see Figure 3).
This display is intended to assist the operator in setting the leak check pressure.
Apply the maximum differential pressure across the molbloc that is normally
encountered during flow measurement while working at your typical absolute
working pressure. Neither pressure should be less than atmosphere. Use the <DP>
indication on the molbox1 display to set the absolute and differential pressure.
Once the pressure setting is correct,
press [ENTER]. The molbox1 actuates
its internal valves to isolate itself from the
molbloc and trap the upstream and
downstream pressures on its RPTs
(see Figure 8). The display is:
Vent molbloc
<ENTER>
ports
Assure that both molbox1 rear panel pressure connections are vented. Since the
pressure quick connections on the molbox1 and the quick-connectors on the
molbox1 pressure connection tubes seal when disconnected, they cannot be
vented by simply disconnecting them. The easiest way to assure that the
connections are vented is to maintain the normal connections to the molbloc,
shut off the molbloc gas source and open one or both ends of the molbloc so it
can vent to atmospheric pressure. Another alternative is to install the non-sealing
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MOLBOX1™ OPERATION AND MAINTENANCE MANUAL
quick connectors (P/N 101889) provided in the molbox accessories (see Section 2.1.2)
into the molbox1 quick connectors.
1.
Channel A High Isolation: Closed
2.
Channel A Low Isolation: Closed
3.
Channel B High Isolation: Closed
4.
Channel B Low Isolation: Closed
5.
Bypass: Closed
Figure 8. molbox1
Internal Pneumatic Schematic - LEAK CHECK molbox CHANNEL A
Once the molbox1 pressure connections are vented, press [ENTER].
1.
The pressure read by the upstream RPT (left),
the downstream RPT (right) and the pressure
unit of measure (middle).
2.
The ratio of the upstream RPT reading to the
downstream RPT reading.
3.
Leak check count down in seconds.
347.466 kPaa 35.459
1.03579:1 WAIT: 60
molbox1 counts down for 60 seconds while monitoring the ratio of the two
pressures and then determines whether an internal leak was present.
A significant leak in a pressure isolation valve or a bypass valve between the two
channels will cause the ratio between the two pressures to vary.
The molbox1 LEAK CHECK function
should end with the prompt:
molbox passed the
leak check
If any other prompt appears, repeat the process. If the leak check fails
consistently, note the failure message and contact a DHI Authorized Service
Provider (see Section 7.4).
Leak Check System

PURPOSE
To leak check the external system that is connected to the molbox1.

PRINCIPAL
It is recommended to run the SYSTEM LEAK CHECK whenever critical physical
connections in the system attached to the molbloc are broken and reconnected.
Critical connections are ones that are between the molbloc and the DUT, which,
if they were to leak, would cause the flow through the molbloc and the DUT to
differ. Whenever a new DUT is connected to the system, it is a good idea to run
the SYSTEM LEAK CHECK.
The SYSTEM LEAK CHECK monitors changes in pressure in a closed system
defined by the user to help determine whether a leak exists in the system. One
of the ways a leak is detected is by monitoring pressure decay in the pressurized
closed system. When the test volume is large, significant leaks may exist without
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3. OPERATION
being detected because the pressure decay caused by the leak is reduced.
Therefore, the SYSTEM LEAK CHECK is most effective when the volume of the
closed system is minimized.
During molbloc-L operation, the SYSTEM LEAK CHECK also measures flow through
the molbloc to help determine whether a leak is present upstream or downstream of
the molbloc. Since molbloc-S is not capable of calculating meaningful flow values
with the very small differential pressure present during this test, the SYSTEM LEAK
CHECK operates differently for molbloc-L and molbloc-S operation, as described in
the  OPERATION sections immediately below.
The SYSTEM LEAK CHECK function uses molbox1’s high precision pressure
and flow measurement capabilities to help determine whether a leak exists in
the system to which the molbloc is connected. This feature is to assist the
operator in flow measurement and calibration. The system to which the
molbloc is connected is the responsibility of the user. Failures in the system
leak check do not normally indicate defects in the molbox1 or molbloc itself.
The molbox1 leak check is used to identify molbox1 failures.

OPERATION – molbloc-L OPERATION
To access the system leak check press [TARE] and select <3leak check>,
<2system>. The display is:
1.
The pressure read by the upstream RPT
(left), the downstream RPT (right) and
the pressure unit of measure (middle).
347.589 kPaa 347.580
<ENTER> when ready
This display is intended to assist the operator in setting the leak check pressure.
molbox1 has actuated internal valves to connect the upstream and downstream
RPTs together, so they are both measuring an equal system pressure. (see Figure 9).
1.
Channel A High Isolation: Open
2.
Channel A Low Isolation: Open
3.
Channel B High Isolation: Closed
4.
Channel B Low Isolation: Closed
5.
Bypass: Open
Figure 9. molbox1
Internal Pneumatic Schematic
- SYSTEM LEAK CHECK - CHECKING OFFSET AND STABILITY
Close an isolation valve downstream or plug the exhaust of the flow system that
is being tested (downstream of the molbloc anxxxxd the DUT if the
molbloc/molbox is being used to test another device).
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Using the molbox1 display to read the pressure, set the pressure to the normal
operating pressure.
FOR SYSTEMS WITH MASS FLOW CONTROLLERS (MFCs):
Keep in mind that the valves in most MFCs are not intended to provide a
complete gas shutoff and so they may not be suitable to close off the test
system. If an MFC is downstream of the molbloc and its downstream port is
open to atmosphere, it is best to close the system by connecting a cap to
the MFC outlet fitting or by connecting a shutoff valve downstream. If the
MFC valve is closed (most MFCs have normally closed valves) when the
operating pressure is applied from the upstream side, most of the gas will
be stopped by the MFC valve and will not immediately fill the volume between
the MFC valve and the downstream cap or valve. If this happens, the gas
may leak by the MFC valve to fill this volume during the test and cause a
pressure decay and an apparent system leak. The solution is to send a setpoint
signal to the MFC to open the MFC valve while pressurizing the system. Then close
the MFC valve (remove the setpoint signal) after the system is pressurized
to avoid heating of the test gas by the energized valve.
Next, close an isolation valve upstream of
the molbloc so the gas supply is no longer
open to the system being checked. Once
the pressure has stabilized, press
[ENTER]. The display is:
347.587 kPaa 347.583
WAIT: 30
The molbox1 is checking:
•
For pressure and temperature stability before running the system leak test
•
That the disagreement between the two RPTs is not excessive
After 30 seconds, if the stability check is not passed, molbox1 displays:
•
If the pressure was not stable:
Leak is too large to
continue
•
If the molbloc temperature change
was too great:
Temp change was too
great to find leaks
•
If the offset between the RPTs was
too great:
Offset excessive
check tare
If any of the above three prompts occurs, check the external system for leaks
and run the molbox1 leak check before proceeding. If the tare was excessive,
tare the molbox1 RPTs before running the leak check again (see Section 3.4.4.1).
Once the 30 second pressure stability/offset
check has been successfully completed,
molbox1 displays:
© 1995 - 2007 DH Instruments, a Fluke Company
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Enter starts 30 sec
system leak test
3. OPERATION
When [ENTER] is pressed, molbox1’s valves actuate to set up the system leak
check configuration which is identical to the normal operating configuration
(see Figure 3). The display becomes:
1.
Pressure read by the upstream RPT (left), the
downstream RPT (right) and the pressure unit
of measure (middle).
2.
Current measured flow.
3.
Time remaining in the leak check in seconds.
347.592 kPaa
0.101 sccm
47.583
30
molbox1 measures pressure and flow for a 30 second countdown. After the
countdown has elapsed, molbox1 displays its conclusion from the
measurements. The display will be either:
possible system
upstream leak
Or
possible system
downstream leak
Or
System passed system
leak check
Upstream and downstream refer to the possible location of the leak relative to the
position of the molbloc and the normal flow direction in the system. If you are
unable to locate a leak in the flow path components, check or replace the
upstream and downstream molbloc to molbox pressure tubes and their connectors
and retry the test. They are a critical part of the pneumatic system and if a significant
leak is present in these tubes, it will cause an error in flow measurement.

OPERATION – molbloc-S OPERATION
In molbloc-S operation, SYSTEM LEAK CHECK is a one-part test which tests for
pressure decay in the closed system.
To access the system leak check press [TARE] and select <3leak check>,
<2system>.
Leak check:
1run 2view
The display is:
If <2view> is selected the test results screen (see below) is displayed with the
results from the most recent leak test.
To run the leak test, select <1run>.
molbox1 actuates internal valves to connect the upstream and downstream RPTs
together, so they are both measuring an equal system pressure. (see Figure 10).
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1.
Channel A High Isolation: Open
2.
Channel A Low Isolation: Open
3.
Channel B High Isolation: Closed
4.
Channel B Low Isolation: Closed
5.
Bypass: Open
Figure 10. molbox1
Internal Pneumatic Schematic
- SYSTEM LEAK CHECK ON CHANNEL A - CHECKING OFFSET AND STABILITY
Close an isolation valve downstream or plug the exhaust of the flow system that
is being tested (downstream of the molbloc and the DUT if the molbloc/molbox is
being used to test another device).
Open an isolation valve upstream of the molbloc to allow the working pressure to
pressurize the system.
FOR SYSTEMS WITH MASS FLOW CONTROLLERS (MFCS)
Keep in mind that the valves in most MFCs are not intended to provide a
complete gas shutoff and so they may not be suitable to close off the test
system. If an MFC is downstream of the molbloc and its downstream port is
open to atmosphere, it is best to close the system by connecting a cap to
the MFC outlet fitting or by connecting a shutoff valve downstream. If the
MFC valve is closed (most MFCs have normally closed valves) when the
operating pressure is applied from the upstream side, most of the gas will
be stopped by the MFC valve and will not immediately fill the volume between
the MFC valve and the downstream cap or valve. If this happens, the gas
may leak by the MFC valve to fill this volume during the test and cause a
pressure decay and an apparent system leak. The solution is to send a
setpoint signal to the MFC to open the MFC valve while pressurizing the
system. Then close the MFC valve (remove the setpoint signal) after the system
is pressurized to avoid heating of the test gas by the energized valve.
Next, close the isolation valve upstream of the molbloc so the gas supply is no
longer open to the system being checked. Once the pressure has had time to stabilize,
press [ENTER].
ENTER to start
60 s leak check
The next display is:
Press [ENTER] to begin the test
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3. OPERATION
The next display is:
1.
The average pressure from the two molbox1
RPTs.
2.
Current absolute pressure measurement in
active pressure unit of measure.
3.
SYSTEM LEAK CHECK count down in
seconds.
199.167 kPa a
leak testing 60s
Press [ESCAPE] to abort the leak test.
Pressing [ENTER] while the test is in progress restarts the test and reset the leak
test timer.
When the test is complete, a test results screen is displayed:
1.
The total change in average pressure over the
test interval.
2.
The currently selected pressure unit of measure.
3.
Average rate of pressure change, per second,
during the test.
ΔP –0.0720 kPa
Rate –0.0012 kPa/s
Since flow systems using molbloc-S will may use widely varying flow rates and
tubing sizes, and test volumes may be quite large, it is difficult to predict what
size pressure rate of change is acceptable to avoid significant flow errors. Your
best guide may be to run the SYSTEM LEAK CHECK often with your hardware,
find a typical rate of change which represents a sound setup, and attempt to
match that rate each time. In any case, you should be able to achieve a rate of
change smaller than 0.01 % / second of the absolute line pressure.
If you observe a relatively large leak rate and are unable to locate a leak in the
flowpath components, check or replace the upstream and downstream molbloc to
molbox pressure tubes and their connectors and retry the test. They are a critical
part of the pneumatic system and if a significant leak is present in these tubes,
it will cause an error in flow measurement.
3.4.4.4

<4AutoZ>
PURPOSE
To offset the molbox1 reference pressure transducers (RPTs) relative to a
reference value in order to compensate for possible changes in RPT zero
between full recalibrations.
To assure operation within measurement uncertainty specifications (see
Section 1.2.2), it is recommended that AutoZ be run (the value of Poffset
updated) whenever molbox1 has been exposed to temperature changes
exceeding ± 15 ºC (36 ºF).
Improper use of the AutoZ function can cause out of tolerance pressure
measurements. AutoZ should be used only by qualified personnel for the
purpose of rezeroing the molbox1 reference pressure transducer absolute
pressure measurement function.
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
PRINCIPAL
AutoZ Purpose and Principle
The main component of the change over time of the molbox1 RPTs is change in
zero or offset, independent of span. Offsetting or “rezeroing” molbox1 RPTs
relative to a reference between recalibrations allows measurement uncertainty
specifications to be maintained with less frequent full calibrations. The molbox1
AutoZero function (AutoZ) provides full on-board support for the rezeroing
process to simplify its application by the user.
The AutoZero function uses three values:
1. Pstd,0: The absolute pressure value indicated by the AutoZ reference, the
device that is acting as the reference relative to which to offset the RPT.
The pressure at which AutoZ is performed is normally atmospheric pressure
and the Pstd,0 value can be supplied a) by manual entry, or b) automatically
from a DHI RPMx Reference Pressure Monitor.
2. Pu,0: The absolute pressure reading of the RPT, with no AutoZ offset, at the
time AutoZ is performed.
3. Poffset: The difference between the absolute pressure reading of the RPT
with no AutoZ offset (Pu,0) and the indication of the AutoZ reference (Pstd,0):
Poffset = Pu,0 - Pstd,0
Poffset represents the change in zero of the RPT relative to the AutoZ standard
(Pstd,0).
The AutoZ function manages the determination, storage and application of Poffset
for both molbox1 RPTs in absolute mode. The AutoZ handles both molbox1
RPTs simultaneously as they are of the same range and always used together.
The source of Pstd,0 must be an absolute pressure, nominally atmospheric
pressure, with uncertainty significantly better than that of the RPT that is being
AutoZeroed (see Section 1.2.2). This can be accomplished with a variety of
digital barometers or with a piston gauge able to set absolute pressure.
When the RPTs are used with AutoZ ON, absolute pressure is calculated as:
Pabs = Pu,0 - Poffset
When RPTs are used with AutoZ OFF, Poffset is ignored.
When the RPT is calibrated, Poffset is set to zero. Poffset is then redetermined at
regular intervals using the AutoZ function. The most recent value of Poffset is
applied to the RPT reading to correct for change in zero over time.
Recommendations for the Use of the AutoZ Function
The AutoZ function provides a powerful and easy to use tool for improving the
stability over time of molbox1 RPTs and maximizing the recalibration interval by
compensating for change in zero between full recalibrations. The following simple
recommendations will help assure that you use this feature to best advantage.
•
Always leave AutoZ ON when operating if the AutoZ routine has been run
regularly using a valid atmospheric reference.
•
Run AutoZ to update Poffset only when a reference whose measurement
uncertainty is known to be significantly better than that of the molbox1 RPTs
is available. Though it may not be practical and generally is not necessary,
the best possible reference with which to run AutoZ in absolute measurement
mode is a gas operated piston gauge (such as a DHI PG7601) applying an
absolute pressure near atmospheric pressure to the molbox1 test port. The
best day to day reference is a properly calibrated DHI RPM4 with a BA100K
RPT interfaced directly as an external device to the molbox1 COM2 port.
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3. OPERATION
•
Allow the molbox1 to stabilize at atmospheric pressure and ambient
temperature for 10 to 15 minutes before running AutoZ.
If AutoZ is on, the AutoZ value will be applied while running the calibration of
molbox RPTs and an AutoZ indication is included in the run calibration screen
(See Section 5.2.4.1).

OPERATION
To access the molbox1 AutoZ function press [TARE], <4AutoZ>. The display is:
1.
Active RPT designator.
2.
Indication of whether AutoZ is currently ON or
OFF for this RPT and measurement mode.
1off 2view
3edit 4run
•
Select <1off> (or <1on>) to change the AutoZ status.
•
Select <2view> to view the current values of Poffset for the two RPTs.
ON
Poffset should be zero when the molbox1 is new or has just been calibrated.
•
Select <3edit> to edit the values of Poffset.
The value of Poffset is always displayed and entered in Pascal (Pa).
•
Select <4run> to run the AutoZ routine which determines and activates Poffset
values by measurement of Pstd,0 (see Section 3.4.4.4.2).
3.4.4.4.1
Edit AutoZ
The edit AutoZ function should be used with great caution as entering
inappropriate values and turning ON AutoZ may result in out of tolerance
measurements. In normal operation, the value of the AutoZ offset, Poffset,
should be changed using the run AutoZ function (see Section 3.4.4.4.2).
Before editing Poffset, see Section 3.4..4.4, PRINCIPLE.
To edit the current Poffset values, press [TARE], <4AutoZ>, <3edit>. The display is:
1.
Edit field for the value of Poffset of the
upstream (1, Hi) RPT.
2.
Edit field for the value of Poffset of the
upstream (1, Hi) RPT.
Poff:18.7 Pa
Poff:-3.5 Pa
UP1
DN2
Edit the Poffset value(s) as desired and press [ENT] to activate the new value(s).
Press [ESC] to abandon changes.
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The value of Poffset is always displayed and entered in Pascal (Pa).
3.4.4.4.2
Run AutoZ
Run AutoZ is the function by which the current RPT reading is compared to a
reference, Pstd,0, at atmospheric pressure to determine a new value of Poffset.
The value of Poffset is then used by AutoZ to automatically correct the RPT for
possible change in zero over time (see Section 3.4.4.4, PRINCIPLE).
To access run AutoZ, press [TARE], <4AutoZ>, <4run>. The display is:
1.
Selection of source of Pstd,0 reference to which
to AutoZ.
AutoZ by:
1Entry 2COM2
Selecting <1Entry> allows the value of Pstd,0 to be entered from the front panel keypad.
Selecting <2COM> allows the value of Pstd,0 to be read automatically from a DHI
RPMx connected to molbox1’s COM2 communications port.
When AutoZ is run, the molbox1 internal valves are actuated to connect both
molbox1 RPTs to the channel A, Hi port on the molbox1 rear panel (see Figure
14 in Section 5.2.4.1). Be sure the channel A, Hi port is fully open to atmosphere
when running AutoZ. Note that the molbox1 quick connectors and molbox1 to
molbloc pressure lines are self sealing and therefore DO NOT open to
atmosphere unless a quick connector stem is inserted. Use a quick connector stem
(DHI P/N 101889, equivalent to Swagelok SS-QM2-S-200) supplied with the
molbox1 accessories to open the port to atmosphere.
Allow the molbox1 to stabilize at atmospheric pressure and ambient
temperature for 10 to 15 minutes before running AutoZ.
If running AutoZ results in a value of Poffset that is greater than ± 0.005 % FS of
the span of the RPT that is being AutoZeroed, the RPT and/or the reference used
as the source of Pstd,0 may be out of tolerance or the AutoZ process may have
been faulty. Before activating a new Poffset greater than ± 0.005 % FS of the
active RPT, check to be sure that both the RPT and the reference were in
good working order, properly vented to stable atmospheric pressure, at the
same height, and reading in the same pressure units when AutoZ was run.
When the run AutoZ selection is made, if a HEAD correction is currently active
(see Section 3.6.8) the head correction is momentarily disabled while
running AutoZ to avoid “zeroing out” the head value.
The value of Poffset is always displayed and entered in Pascal (Pa).
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3. OPERATION
Run AutoZ by Entry
AutoZ by entry allows the value of Pstd,0 (see Section 3.4.4.4, PRINCIPLE) to be
entered directly from the molbox1 front panel. This provides a simple way of
AutoZeroing relative to an independent reference device such as a house
barometer that does not interface directly with molbox1.
To access run AutoZ by entry press [TARE], <4AutoZ>, <4run>, <1Entry>.
The display is:
1.
Real time reading (without head correction) of
upstream (1, Hi) RPT in unit of measure on
line 2.
2.
Real time reading (without head correction) of
downstream (2, Lo) RPT in unit of measure on
line 2.
3.
Entry field for the value of Pstd,0. in the current
pressure unit of measure.
96.7715U
96.7778D
Pstd,0:96.7752 kPa
Enter the value of the AutoZ reference (Pstd,0) in the same unit of measure as the
display and press [ENT]. molbox1 logs the readings and calculates a new
AutoZ offset value. The next display is:
1.
Current/previous value
upstream (1, Hi) RPT.
of
Poffset
for
the
2.
Current/previous value of
downstream (2, Lo) RPT.
Poffset
for
the
3.
New value of Poffset for the upstream (1, Hi)
RPT for the AutoZ that was just run.
4.
New value of Poffset for the downstream (2, Lo)
RPT for the AutoZ that was just run.
Old: 0.0 Pa 0.0
New: 3.7 Pa 2.6
Press [ENT] to activate the new values of Poffset or [ESC] to start over with entry
of a new AutoZ reference (Pstd,0) value.
The value of Poffset is always in Pascal (Pa). The value of Pstd,0 is entered in
the current pressure unit of measure.
Run AutoZ by COM2
AutoZ by COM2 allows a DHI RPMx Reference Pressure monitor connected to the
molbox1 COM2 to act as the AutoZ reference (source of Pstd,0) (see Section 3.4.4.4,
PRINCIPLE). The RPMx is read and the new Poffset is calculated automatically.
To access run AutoZ by COM2 press [TARE], <4AutoZ>, <4run>, <2COM2>.
For molbox1 to communicate with an RPMx connected to its COM2 port, the
molbox1 and the RPMx RS-232 interfaces must be set up properly (see
Section 3.6.6.1). If, the molbox1 is unable to locate an RPM ON COM2 when running
AutoZ by COM2, it times out after 6 seconds and displays an error message.
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If molbox1 is able to communicate with an RPMx on its COM2 port, the display is:
1.
Real time reading (without head correction) of
upstream (1, Hi) RPT in unit of measure on
line 2.
2.
Real time reading (without head correction) of
downstream (2, Lo) RPT in unit of measure on
line 2.
3.
Real time reading of the RPMx connected to
molbox1 COM2 to provide the value of AutoZ
Poffset.
96.7715U
96.7778D
Pstd,0:96.7752 kPa
Observe the pressure outputs verify that they are stable. A 10 to 15 minute wait,
after venting, is recommended before running AutoZ. When ready, press [ENT]
to cause AutoZ to run. molbox1 logs both RPT readings and calculates a new
AutoZ offset value. The display is:
1.
Current/previous value
upstream (1, Hi) RPT.
of
Poffset
for
the
2.
Current/previous value of
downstream (2, Lo) RPT.
Poffset
for
the
3.
New value of Poffset for the upstream (1, Hi)
RPT for the AutoZ that was just run.
4.
New value of Poffset for the downstream (2, Lo)
RPT for the AutoZ that was just run.
Old: 0.0 Pa 0.0
New: 3.7 Pa 2.6
Press [ENT] to activate the new values of Poffset or [ESC] to start over.
The value of Poffset is always displayed and entered in Pascal (Pa).
3.4.4.5

<5BPR> (molbloc-S OPERATION ONLY)
PURPOSE
To quickly measure the molbloc-S upstream and downstream pressure and
calculate and display the BPR (back pressure ratio) when molbox1 is in a
molbloc-S BPR mode which would not otherwise measure the BPR.
The <5BPR> menu selection is only present during molbloc-S operation.

PRINCIPAL
molbox1 uses the back pressure ratio, or BPR (the ratio of the molbloc-S
downstream absolute pressure to the upstream absolute pressure) to determine
whether the flow through the throat of the molbloc-S Venturi nozzle is critical and
flow measurements within predictable uncertainty limits can be made with
molbloc-S (see Section 3.1.5). When operating molbox1 with molbloc-S, the
user may select different BPR monitoring modes (see Section 3.6.9). Depending
on which BPR mode is selected, the BPR value is not always measured. The
BPR function allows the user to measure and display BPR directly at any time
regardless of which BPR mode is selected.
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3. OPERATION

OPERATION
Select [TARE], <5BPR>. The display is:
1.
2.
The current pressure read by the upstream
(left) and downstream (right) RPTs without
taking into account the current tare value.
These are untared readings in the current
pressure unit of measure.
259.312 kPa ↓99.5769
BPR 0.38
The current BPR (ratio of downstream to
upstream absolute pressure).
Press [ENTER] or [ESCAPE] to exit the BPR function and return to the previous
RUN screen and BPR mode.
3.4.5
[P&T] (PRESSURE AND TEMPERATURE)
 PURPOSE
To provide continuous display of the pressures measured by molbox1, the Reynolds number
of the flow through the molbloc, the temperature of the molbloc and other pressure
measurement information depending on whether the molbox1 is used with molbloc-L or
molbloc-S.
 PRINCIPLE
molbox1 continuously measures pressures and molbloc temperature and uses these
measurements to calculate flow.
The pressure at the molbloc upstream and downstream ports is read by two absolute
Reference Pressure Transducers (RPTs). In molbloc-L operation, the flow is calculated from
the differential pressure across the molbloc. The differential pressure is calculated as the
difference between the two, tared (see Section 3.4.4.1.1), absolute RPTs (upstream downstream) and is displayed in the molbloc-L mode pressure screen.
In molbloc-S mode, the flow is calculated from the molbloc-S upstream pressure. The
upstream pressure may be read by either one or both of the RPTs, depending on which BPR
mode is in use (see Section 3.6.9). When the molbox1 is in a valve state called BPR OFF,
the molbloc-S downstream pressure is not measured and both RPTs are used to measure
the molbloc-S upstream pressure. Their readings are averaged to reduce the uncertainty of
the molbloc-S upstream pressure measurement. An indicator is used next to the “downstream”
RPT value to show whether the RPT is currently measuring the molbloc downstream or
upstream pressure. Whenever the molbloc-S downstream pressure is measured, the BPR is
calculated and shown in the P&T pressure screen. When both RPTs measure the upstream
pressure (BPR OFF mode), the indicated pressure for both RPTs is adjusted to equal the
average of the two using the dynamic tare and BPR is no longer displayed.
Since the displays and operation of the P&T pressure screen are different for molbloc-L and
molbloc-S, they are described separately in Sections 3.4.5.1 and 3.4.5.2.
For temperature measurement, two Platinum Resistance Thermometers (PRTs) are embedded
in each molbloc. These are connected to the molbox1 by the molbox1 to molbloc cable. The
molbox1 ohmic measurement system reads the resistance of the PRTs and calculates
molbloc temperature.
molbox1 continuously calculates the Reynolds number of the flow through the molbloc.
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The molbox1’s current pressure and temperature readings as well as the Reynolds number of
the current flow can be displayed using the P&T function.
3.4.5.1

molbloc-L OPERATION
OPERATION – molbloc-L Operation
Press [P&T] from any run screen. The display is:
1.
Pressure read by the upstream RPT (left), the
downstream RPT (right) and the pressure unit
of measure (middle).
2.
The current differential pressure in the current
pressure unit of measure. <DP> indicates the
value is differential pressure.
3.
Current Reynolds number of the flow through
the molbloc.
97.788 kPaa 97.783
DP 0.005
Re
0.02
Pressing [P&T] again or the [+/-] key toggles between the pressure screen and
the temperature screen:
1.
The average molbloc temperature in the
current unit of measure (upstream +
downstream/2).
2.
The temperature measured by the upstream
molbloc platinum resistance thermometer in the
current unit of measure.
3.
The temperature measured by the downstream
molbloc platinum resistance thermometer in the
current unit of measure.
21.80ºC
21.82ºC
21.78ºC
To leave the P&T function and return to the MAIN run screen, press [ESCAPE].
To change the pressure and/or temperature unit of measure, see Sections
3.5.8 and 3.5.9.
3.4.5.2

molbloc-S OPERATION
OPERATION – molbloc-S operation
1.
The current pressure read by the upstream
(left) and downstream (right) RPTs and the
current pressure unit of measure (middle). In
BPR OFF or Auto modes, tare is automatically
applied to these readings. In BPR ON mode,
tare is never applied.
2.
<h> indicates a head pressure correction is
applied or no character if no head correction.
3.
Arrow to indicate which pressure is being read
by the “downstream” RPT.
Down arrow
indicates downstream pressure, Up arrow
indicates upstream pressure.
4.
The current BPR (ratio of downstream to
upstream absolute pressure).
5.
Current Reynolds number.
© 1995 - 2007 DH Instruments, a Fluke Company
Page 66
259.312 kPah↓99.5769
BPR 0.38
Re 11039
3. OPERATION
Pressing [P&T] again or the [+/-] key toggles between the pressure screen and
the temperature screen:
1.
The average molbloc temperature in the
current unit of measure (upstream +
downstream/2).
2.
The temperature measured by the upstream
molbloc platinum resistance thermometer in the
current unit of measure.
3.
The temperature measured by the downstream
molbloc platinum resistance thermometer in the
current unit of measure.
21.80ºC
21.82ºC
21.78ºC
To leave the P&T function and return to the MAIN run screen, press [ESCAPE].
To change the pressure and/or temperature unit of measure, see Sections 3.5.8
and 3.5.9.
3.4.6
[DISPLAY]
 PURPOSE
To select, from a variety of choices, the information that is displayed on the second line of the
molbox1 display. Averaging is one of the choices.
 PRINCIPLE
molbox1 supports a variety of ADVANCED FLOW MEASUREMENT functions that are
displayed on the second (bottom) line of the molbox1 display. In summary, the available
DISPLAY functions included are:
RATE:
Calculates and displays the current rate of change of flow in current flow
units/second (see Section 3.4.6.1). This function is a useful indication of the
stability of the flow being measured. It is often used as an indication of positive
or negative leak rate and as a “go/no go” criterion for when to take data when
comparing molbox1 and a DUT (e.g., in a calibration).
AVERAGE:
Calculates the average flow measurement over a user specified period of time
and displays the average, the standard deviation about the mean and a
countdown in seconds to the next average (see Section 3.4.6.2). This function
is often used to filter out flow noise in an unstable system or to gather a
corresponding sample when comparing molbloc/molbox measurements to
another device with a long integration time (e.g., a volumetric flow standard).
The magnitude of the noise is quantified by the standard deviation about the
mean. A second screen allows the instantaneous flow values to be viewed
during an averaging cycle.
HI/LO:
Records and displays the maximum and minimum flows measured since HI/LO
reset (see Section 3.4.6.3). This function is used to keep track of the minimum
and maximum flow observed over a period of time or to monitor whether a flow
min/max limit has been exceeded.
TOTAL:
Totalizes the mass or volume flowed over a period of time (see Section
3.4.6.4). Used to measure total mass or volume over a period of time. Can be
useful in calibration or verifying a totalizing flow device, when comparing
molbloc/molbox to a gravimetric standard or to add or remove a specific
quantity of mass or volume from a system.
Page 67
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MOLBOX1™ OPERATION AND MAINTENANCE MANUAL
UNIT:
Displays the measurement of flow through the molbloc simultaneously in a
second flow unit (see Section 3.4.6.5). This function is convenient when
working with an unfamiliar flow unit of measure to simultaneously display a
familiar unit or any time a real time flow unit conversion is desired.
DEVIATION: Continuously calculates and displays the deviation between the current flow
measured by molbox1 and a target flow defined by the user (deviation =
current flow - target) (see Section 3.4.6.6). This function is useful in monitoring
the evolution of flow around and/or away from a desired set point.
FREEZE:
Captures and displays the instantaneous flow value measured by molbox1
when the [ENTER] key is pressed (see Section 3.4.6.7). This function is useful
to record the flow present at the time of an operator observed trigger event.
CLEAN:
Blanks out the second line of the display (see Section 3.4.6.8). This function is
used when a simple display of flow measured by the molbox1, without
additional information, is desired.
 OPERATION
To select a DISPLAY function, press [DISPLAY] from the MAIN run screen.
1avg 2rate 3hi/lo
The display is:
4total 5unit 6dev
7freeze 8clean
↓
The cursor is on the active DISPLAY function. Selecting a DISPLAY function returns to the
MAIN run screen with the selected function active.
See Section 3.4.6, PRINCIPLE for a summary of DISPLAY functions and Sections 3.4.6.1
through 3.4.6.8 for detailed information on each DISPLAY function.
In molbloc-S operation, at times, the back pressure ratio, BPR, will be too high for molbox1
to calculate a meaningful flow value. When this occurs, the top line of the run screen
display always reads <BPR HI> and the bottom line shows the label <BPR> and the
current measured BPR value. This display has priority over the appearance of the display
functions described in this section, but the display will return to normal when the BPR
returns to a usable level for molbloc-S measurements (see Section 3.1.5).
The default DISPLAY function is RATE which causes the second line of the display to show
<R> followed by the current rate of change of flow in current flow unit of measure per
second (see Section 3.4.6.1).
3.4.6.1

<1RATE>
PURPOSE
To activate the RATE DISPLAY.
See Section 3.4.6, PRINCIPLE.
© 1995 - 2007 DH Instruments, a Fluke Company
Page 68
3. OPERATION

OPERATION
To activate the RATE DISPLAY press [DISPLAY] and select <1rate>. Selecting <1rate>
returns to the MAIN run screen with the RATE DISPLAY active.
With the RATE DISPLAY active, the MAIN run screen is:
1.
Standard MAIN run screen top line.
2.
Current rate of change of flow in current flow
unit of measure per second.
* 101.27 sccm
R 0.03/sec
N20
The RATE DISPLAY is different and separate from the stability setting which
is used to set the stability criterion on which the Ready/Not Ready
indication is based (see Sections 3.1.3, 3.5.2). The RATE DISPLAY only
causes the current rate of change to be displayed and has NO affect on the
stability setting or the Ready/Not Ready condition.
To go to a DISPLAY other than RATE, press [DISPLAY] and make a new
DISPLAY choice.
3.4.6.2

<2Avg> (Average)
PURPOSE
To activate the AVERAGE DISPLAY and/or adjust the period of time over which
averaging occurs.
See Section 3.4.6, PRINCIPLE.

OPERATION
To access the AVERAGE DISPLAY, press [DISPLAY] and select <2avg>.
The display is:
1.
Edit field for averaging period in seconds.
Default is 20. Minimum 3, maximum 999.
Averaging Period:
20 s
Edit the averaging time period if desired. Pressing [ENTER] returns to the MAIN
run screen with the AVERAGE DISPLAY active.
With the AVERAGE DISPLAY active the MAIN run screen is:
1.
Average flow measured over last completed
averaging period.
2.
Standard deviation
averaging period.
3.
Countdown in seconds until completion of ongoing averaging period.
of
last
Page 69
completed
* 101.99 sccm
N20
δ 0.06
18 sec
© 1995 - 2007 DH Instruments, a Fluke Company
MOLBOX1™ OPERATION AND MAINTENANCE MANUAL
The AVERAGE DISPLAY has a second screen that allows the instantaneous
flow readings to be viewed while an averaging cycle is running. This screen is
available only if the molbox1 MFC control option is NOT present or OFF. If the
molbox1 MFC control option is not present or OFF, pressing [+/-] toggles
between the MAIN run AVERAGE screen and the instantaneous values
AVERAGE screen. If the molbox1 MFC control option is ON, pressing [+/-]
accesses the MFC averaging screens. The MFC averaging screens are the
equivalent of the normal MFC screens but the values are averaged for the
averaging time. The instantaneous AVERAGE screen is:
1.
Instantaneous flow value at molbox1’s normal
integration rate.
2.
Countdown in seconds until completion of ongoing averaging period.
3.
Current rate of change of flow in flow unit of
measure/second..
3.4.6.3

* 101.59 sccm
N20
R 0.0025
18 sec
<3 HI/LO>
PURPOSE
To activate the HI/LO DISPLAY.
See Section 3.4.6, PRINCIPLE.

OPERATION
To activate the HI/LO DISPLAY press [DISPLAY] and select <3hi/lo>. Selecting
<3hi/lo> resets the HI/LO values and returns to the MAIN run screen with the
HI/LO DISPLAY active.
With the HI/LO DISPLAY active, the MAIN run screen is:
1.
Standard MAIN run screen top line.
2.
Highest flow observed since HI/LO reset.
3.
Lowest flow observed since HI/LO reset.
* 101.22 sccm
N20
H 101.44
L99.113
The HI/LO values change each time a new HI or LO flow value occurs.
The HI/LO record can be reset at any time by pressing [ENTER] allowing a
HI/LO reset without going back through the DISPLAY menu.
When DISPLAY is set to HI/LO, the MFC indicator of the optional MFC function
is not included on the second line of the molbox1 display as the HI/LO DISPLAY
occupies the entire second line of the molbox1 display (see Section 3.4.8).
The set point of the optional MFC function cannot be changed in the HI/LO
display because [ENTER] is used by the DISPLAY function. MFC set point
can only be entered in the RATE, UNIT or CLEAN DISPLAY functions.
Changing the flow unit of measure, the gas, the K factor or running a TARE
function while in HI/LO resets the HI/LO record.
© 1995 - 2007 DH Instruments, a Fluke Company
Page 70
3. OPERATION
To go to a DISPLAY other than HI/LO, press [DISPLAY] and make a new
DISPLAY choice.
3.4.6.4

<4Total> (Totalizer)
PURPOSE
To activate the TOTALIZER DISPLAY.
See Section 3.4.6, PRINCIPLE.

OPERATION
To activate the TOTALIZER DISPLAY, press [DISPLAY] and select <4total>.
The display is:
1.
Edit field for time over which to totalize
(hh:mm:ss).
Default period is 00:10:00;
maximum 99:59:59.
Totalizing period:
00:10:00
Edit the totalizing period as desired. Pressing [ENTER] returns to the MAIN run
screen with the TOTALIZER DISPLAY active.
With the TOTALIZER DISPLAY active the MAIN run screen is:
1.
Standard MAIN run screen top line.
2.
Total mass or volume accumulated over
elapsed totalizing run time.
3.
Units of measure of mass or volume (derived
from the current flow unit) of the totalized
value (see Table 22). The units of measure
are not shown if the screen space is needed
to show a large totalized value.
4.
* 101.45 sccm
Σ0.00 scc
N20
00:00:00
Elapsed totalizing time (hh:mm:ss). Always
starts from zero and counts up until totalizing
period elapses.
Press [ENTER] to start totalizing. The elapsed time counter starts and the total
mass or volume begins to accumulate. Totalizing continues until the set totalize
period is complete. When the totalizing period is complete, molbox1 sounds
three beeps and displays the totalizing complete screen in which the total flow or
volume and elapsed totalizing time are frozen with totalizing time NOT flashing.
To start a new totalizing run from the totalizing complete screen, press [ENTER].
This clears the previous total, resets to the totalizing timer and starts totalizing.
When DISPLAY is set to TOTALIZE, the MFC indicator of the optional MFC
function is not included on the second line of the molbox1 display as the
TOTALIZE DISPLAY occupies the entire second line of the molbox1 display
(see Section 3.4.8).
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MOLBOX1™ OPERATION AND MAINTENANCE MANUAL
The set point of the optional MFC function cannot be changed in the
TOTALIZE display because [ENTER] is used by the DISPLAY function. MFC
set point can only be entered in the RATE, UNIT or CLEAN DISPLAY
functions.
To view a split total and/or to start a new totalizing run with a new run time,
press [ENTER] while totalizing (see Viewing a Split Total and/or Starting a
New Totalizing Run with a New Run Time of this section). To change
totalizing run time any other time, press [DISPLAY] and select <4total>.
Certain functions cannot be executed while totalizing. These functions
include change K, change gas, change flow unit of measure, tare. If <Access
restricted while totalizing> is displayed when a function key is pressed
during totalizing, the function is one that cannot be executed while
totalizing. To execute the function, abort the totalizing run or wait until
after the run has completed. This feature is to avoid accidentally aborting or
corrupting a totalizing run.
To set a new totalizing time without going back through the [DISPLAY] menu,
press [ENTER] and select <2new> from the TOTALIZER screen. To freeze a
split total without stopping the totalizing run, press [ENTER] or [ESCAPE]
while totalizing (see Viewing a Split Total and/or Starting a New Totalizing
Run with a New Run Time below in this section).
Table 22. Flow Units and Corresponding Total Mass or Volume Units
© 1995 - 2007 DH Instruments, a Fluke Company
FLOW UNIT
TOTAL MASS OR
VOLUME UNIT
mol/s
mol
kg/s
kg
mg/s
mg
slh or slm
sl
sccm
scc
scfh or scfm
scf
Ulm
ul
Uccm
ucc
ucfm or ucfh
ucf
plm or plh
pl
pccm
pcc
pcfm or pcfh
pcf
lm or lh
l
ccm
cc
m3m or m3h
m3
cfm or cfh
cf
Page 72
3. OPERATION
3.4.6.5

<5Unit>
PURPOSE
To activate the UNIT DISPLAY.
See Section 3.4.6, PRINCIPLE.

OPERATION
To activate the UNIT DISPLAY, press [DISPLAY] and select <5unit>. The unit
of measure that will be used for the second line of the MAIN run screen display
must then be selected. The unit selection process is identical to that of the
[UNIT] function key (see Section 3.4.3). Once the unit has been selected
operation returns to the MAIN run screen with the UNIT DISPLAY active.
With the UNIT DISPLAY active the MAIN run screen is:
1.
Standard MAIN run screen top line.
2.
Flow equivalent of the current measured flow
in the alternate flow unit of measure.
3.
Alternate flow unit of measure selected in
UNIT DISPLAY.
* 101.27 sccm
= 0.1013 slm
N20
The reference temperature setting for the user units (i.e., uccm and ulm)
(see Section 3.4.3.3) and the temperature and pressure settings for volume
units (see Section 3.4.3.4) apply to the units in the main UNIT selections as
well as the UNIT DISPLAY selection. Therefore, it is not possible to
simultaneously display user units or volume units with different reference
temperatures and/or pressures. When you change the temperature or
pressure setting for one type of unit, you change it for that type of unit
wherever it is used. It is possible to show the difference between
volumetrically based mass flow units at 0 °C and another temperature by
choosing the “s” version (e.g., sccm) for 0 °C as the main unit and a user unit
with a different reference temperature as the UNIT DISPLAY, or vice-versa.
To go to a DISPLAY other than UNIT, press [DISPLAY] and make a new
DISPLAY choice.
3.4.6.6

<6Deviation>
PURPOSE
To activate the DEVIATION DISPLAY and/or edit the deviation target.
See Section 3.4.6, PRINCIPLE.
Page 73
© 1995 - 2007 DH Instruments, a Fluke Company
MOLBOX1™ OPERATION AND MAINTENANCE MANUAL

OPERATION
To activate the DEVIATION DISPLAY, press [DISPLAY] and select <6dev>.
The display is:
1.
Edit field to edit the target value from which
the deviations is to be measured.
Target:
100.00 sccm
Edit the desired target value. Pressing [ENTER] returns to the MAIN run screen
with DEVIATION DISPLAY active using the entered target value.
With the DEVIATION DISPLAY active the MAIN run screen is:
1.
Standard MAIN run screen top line.
2.
Target value in current flow unit of measure.
3.
Deviation of current flow from target value in
% of reading.
* 100.53 sccm
N20
D 0.53 %
T 100.00
Pressing [ENTER] from the MAIN run screen when the DEVIATION DISPLAY is
active goes directly to the target editing screen. This allows the target value
to be changed without going through the DISPLAY menu.
The DEVIATION DISPLAY target value is the value from which % deviations (D)
are measured by the DEVIATION DISPLAY following:
D = (current flow – target) x 100
target
To go to a DISPLAY other than DEVIATION, press [DISPLAY] and make a new
DISPLAY choice.

PURPOSE
To activate the DEVIATION DISPLAY and/or edit the deviation target.
See Section 3.4.6, PRINCIPLE.

OPERATION
To activate the DEVIATION DISPLAY, press [DISPLAY] and select <6dev>.
The display is:
1.
Edit field to edit the target value from which
the deviations is to be measured.
Target:
100.00 sccm
Edit the desired target value. Pressing [ENTER] returns to the MAIN run screen
with DEVIATION DISPLAY active using the entered target value.
© 1995 - 2007 DH Instruments, a Fluke Company
Page 74
3. OPERATION
With the DEVIATION DISPLAY active the MAIN run screen is:
1.
Standard MAIN run screen top line.
2.
Target value in current flow unit of measure.
3.
Deviation of current flow from target value in
current flow unit of measure.
* 100.53 sccm
N20
D 0.53
T 100.00
When DISPLAY is set to DEVIATION, the MFC indicator of the optional MFC function
is not included on the second line of the molbox1 display as the DEVIATION
DISPLAY occupies the entire second line of the molbox1 display (see Section 3.4.8).
The set point of the optional MFC function cannot be changed in the
DEVIATION display because [ENTER] is used by the DISPLAY function. MFC set
point can only be entered in the RATE, UNIT or CLEAN DISPLAY functions.
Pressing [ENTER] from the MAIN run screen when the DEVIATION DISPLAY is
active goes directly to the target editing screen. This allows the target value
to be changed without going through the DISPLAY menu.
The DEVIATION DISPLAY target value is the value from which deviations (D)
are measured by the DEVIATION DISPLAY following:
D = current flow - target
If the flow unit is changed while the DEVIATION DISPLAY is active, the target
value remains at the same numerical value. It is not converted to the new unit.
To go to a DISPLAY other than DEVIATION, press [DISPLAY] and make a new
DISPLAY choice.
3.4.6.7

<7Freeze>
PURPOSE
To activate the FREEZE DISPLAY.
See Section 3.4.6, PRINCIPLE.

OPERATION
To activate the FREEZE DISPLAY press [DISPLAY] and select <7freeze>.
Selecting <7freeze> returns to the MAIN run screen with the FREEZE DISPLAY active.
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© 1995 - 2007 DH Instruments, a Fluke Company
MOLBOX1™ OPERATION AND MAINTENANCE MANUAL
With the FREEZE DISPLAY active, the MAIN run screen is:
1.
Standard MAIN run screen top line.
2.
Flow measured in the current flow units when
[ENTER] was pressed (displays 0.00 by
default when FREEZE DISPLAY is first
activated).
* 101.75 sccm
F 99.24
N20
Pressing [ENTER] causes the current flow measured by the active molbox1
range to be captured and displayed.
If the flow measurement unit is changed while the FREEZE DISPLAY is active,
the FREEZE value defaults back to zero.
The set point of the optional MFC function cannot be changed in the FREEZE
display because [ENTER] is used by the DISPLAY function. MFC set point
can only be entered in the RATE, UNIT or CLEAN DISPLAY functions.
To go to a DISPLAY other than FREEZE, press [DISPLAY] and make a new
DISPLAY choice.
3.4.6.8

<8Clean>
PURPOSE
To activate the CLEAN DISPLAY.
See Section 3.4.6, PRINCIPLE.

OPERATION
To activate the CLEAN DISPLAY press [DISPLAY] and select <8clean>.
Selecting <8clean> returns to the MAIN run screen with the CLEAN DISPLAY active.
With the CLEAN DISPLAY active, the MAIN run screen is:
1.
Standard MAIN run screen top line.
2.
“Clean” second line.
* 101.45 sccm
N2O
The MFC indicator is not included in the MAIN run screen in the CLEAN
DISPLAY function (see Section 3.4.8).
To go to a DISPLAY other than CLEAN, press [DISPLAY] and make a new
DISPLAY choice.
© 1995 - 2007 DH Instruments, a Fluke Company
Page 76
3. OPERATION
3.4.7
[A/B]
 PURPOSE
To switch the active molbloc channel between channel A and channel B.
 PRINCIPLE
See Section 3.1.1
 OPERATION
Pressing the [A/B] key changes the active molbloc channel. The currently active channel is
indicated by the lit RED LED below the molbox1 front panel display. When the A/B function
is operated, molbox1 actuates internal valves to change the molbloc channel that is
connected to the molbox1's internal pressure transducers. Pressing the [A/B] key also
aborts any A_B mode that may be active (see Section 3.5.4).
When channels are changed using the A/B function, the molbloc is not initialized by
the molbox1. When the molbloc connected to a channel is changed, use <1molbloc> in the
SETUP menu (see Section 3.5.1) to reinitialize. This will cause the molbox1 to read and
store the molbloc EEPROM information and assure that the newly connected molbloc is
properly identified and used.
Channels, Functions and Settings
In general, molbox1 functions and settings are channel specific. They are set and stored
individually for each channel so that changing settings for one channel does not change the
setting for the other.
The only functions and settings that are NOT channel specific are:
Functions:
[MFC], [DISPLAY]
Setup Menu:
<3adj>
Special Menu: <9BPR>
3.4.8 [MFC](OPTIONAL)
 PURPOSE
To turn the analog MFC control function ON and OFF and to select an MFC profile to be used
when the MFC function is ON.
The MFC control function is an optional feature of molbox1 that allows setting and
reading an external MFC with analog voltage or current signals. If the molbox1 does not
include the MFC control function, [MFC] has no function.
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MOLBOX1™ OPERATION AND MAINTENANCE MANUAL
 OPERATION
When [MFC] is first pressed the screen prompts
the operator:
SELECT MFC CHANNEL
(0 DISABLES): 0
The MFC channel refers to the channel of the optional MFC switchbox that can be
purchased as an accessory to molbox1 to allow the MFC control function to be switched
between up to five MFCs. Entering [0] disables the MFC control function. Entering [1], [2],
[3], [4] or [5] enables the MFC function and selects the corresponding channel on the MFC
switchbox. If an MFC switchbox is not being used, select channel #1 when activating the
MFC function.
SELECT PROFILE
#3
The operator is then prompted:
The number refers to the MFC profile number (see Sections 3.4.8.2, 3.5.5). Edit the profile
number to the desired profile. When the profile number is entered, a summary of the profile
is displayed. When [ENTER] is pressed again, the display returns to the MAIN run screen
and the MFC function is active using the profile selected. <MFC> or <MFM> (depending on
the device type of the selected profile) and the active channel number may be displayed in
the bottom right hand corner of the MAIN run screen depending on the current display mode
(see Section 3.4.6).
When the MFC function is ON, pressing [ENTER] from the MAIN run screen or an MFC run
screen allows entry and execution of the MFC set point command. When the DISPLAY
MODE is AVERAGE, HI/LO, TOTAL, DEVIATION or FREEZE, [ENTER] is used for the
DISPLAY MODE (see Section 3.4.6). MFC set point commands cannot be entered in these
DISPLAY MODES. MFC set points can only be entered in the RATE, UNIT and CLEAN
DISPLAY MODES.
To [ENTER] MFC set point, the DISPLAY MODE must be RATE, UNIT or CLEAN. In other
DISPLAY MODES, [ENTER] is used by the DISPLAY MODE.
Pressing the [Ö] arrow key any time the MFC control function is active causes an instant
display of the current MFC profile summary allowing a quick check of the characteristics
of the currently active MFC profile. Pressing [ESCAPE] returns from MFC profile screen
to the last run screen.
3.4.8.1
MFC RUN SCREENS
When the MFC function is ON, the MAIN run screen is unchanged but <MFC> or
<MFM> and the active MFC channel number are shown in the bottom right hand
corner of the molbox1 display (in RATE, UNIT and FREEZE DISPLAY modes only,
see Section 3.4.6). Two or three, depending on the MFC profile in use, special
MFC run screens can be accessed by pressing the [+/-] key. When the [+/-] key
is pressed from the first MAIN run screen, the first MFC run screen is displayed:
© 1995 - 2007 DH Instruments, a Fluke Company
Page 78
3. OPERATION
1.
Ready/not ready indication.
2.
Flow value and flow unit of the flow through
the active molbloc as read by the molbox1.
3.
The gas that is currently being flowed through
the active molbloc.
4.
MFC set point set by the molbox1.
5.
MFC output measured by the molbox1.
6.
Unit of measure of MFC setpoint and output
(V, mA, % FS or blank if flow units).
* 101.001 sccm N2
S1.020 M1.03 V
Pressing [+/-] from the first MFC run screen causes the second MFC run screen
to be displayed (this screen is not present when MFC profile #1 or #2 is being
used, see Section 3.4.8.2, 3.5.5):
1.
Ready/not ready indication.
2.
Flow value and flow unit of the flow through
the active molbloc as calculated by the
molbox1.
3.
The gas that is currently being flowed through
the active molbloc.
4.
The MFC measurement error in % calculate
as ⎛⎜ MFC − molbox1⎞⎟ •100
⎝ MFC F.S. ⎠
* 101.001 sccm N2
E 0.85% F.S.
Pressing [+/-] from the second MFC run screen causes the third MFC run screen
to be displayed (this is the second screen if MFC profile #1 or #2 is in use, see
Section 3.4.8.2, 3.5.5).
1.
Positive MFC supply voltage.
2.
Negative MFC supply voltage.
3.
Current MFC valve voltage.
4.
Current MFC set point.
+ 15.11 V
S1.020 V
-15.15V
11.29V
Summary
Pressing [+/-] toggles the run screens from the MAIN run screen through the
MFC run screens and back to the MAIN run screen.
3.4.8.2
MFC PROFILES
MFC profiles are used by molbox1 to configure the MFC function. MFC profiles
define the analog signal range of the MFC and the relationship between the
analog signal range and the flow range of the MFC. This information allows
molbox1 to operate with the correct signal for the current MFC and to convert the
MFC analog signals to the corresponding flow or % FS values when desired.
MFC profiles are created and edited in [SETUP], <5MFC> (see Section 3.5.5).
3.4.8.3
UNITS OF MEASURE WHEN USING THE MFC CONTROL
OPTION
When the MFC function is active, the molbox1 flow units of measure are always
the units of measure specified in the active MFC profile.
When the MFC function is active, unless the profile is #1 or #2, the flow unit of
measure in which the flow through the molbloc is displayed is determined by the
flow unit of measure in the MFC profile. The [UNIT] function key is for selection
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of the unit of measure of the MFC setpoint and output. The choices available are
V or mA (depending on the active MFC profile's analog range), % FS or flow.
The % FS selection causes MFC setpoint and output to be displayed in % FS of
the MFC which molbox1 calculates using the definition of analog range and flow
range contained in the MFC profile. The flow unit selection causes MFC setpoint
and output to be displayed in the flow units of the MFC calculated using the
definition of analog range, flow range and flow units contained in the MFC profile.
MFC profiles #1 and #2 are default profiles for working with the MFC function
directly in analog units without an MFC flow range or units. Profile #1 is 0 to
5 V, profile #2 is 4 to 20 mA. When the MFC function is active with profile #1
or #2 selected, the MFC units of measure are always V (profile #1) or mA
(profile #2). The UNIT function selects the molbox1 flow measurement unit.
3.4.9 [RES]
 PURPOSE
To set the resolution of molbox1’s display of the flow through the molbloc and other flow
display and entry values.
 PRINCIPLE
The resolution with which the flow measured by molbox1 is displayed can be adjusted. This feature
can be used to reduce the resolution when lower precision measurements are being made
and additional digits might confuse or distract the operator.
The resolution setting determines the number of digits with which flow is displayed. The desired
resolution is calculated based on the nominal full scale range of the molbloc in the current gas
and flow unit of measure and then rounded to the furthest digit to the right (i.e., resolution of 0.001
% on a 100 sccm molbloc is 0.001 sccm).
The default molbox1 display resolution setting is 0.001 % of molbloc FS. The RES setting
does not affect the resolution of flow information transmitted remotely.
Remote information always has maximum resolution of 0.0001 % of molbloc FS.
 OPERATION
To access the resolution function press [RES].
Press the [←] to decrease the resolution and [→] to increase the resolution. Each press
changes the resolution by a factor of 10. Once the desired resolution is displayed, press
[ENTER] to set the selected resolution and return to the main run screen.
The resolution setting affects the display of the measured flow as well as other
indications and settings (i.e., quantities shown by the [DISPLAY] functions).
© 1995 - 2007 DH Instruments, a Fluke Company
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3. OPERATION
3.5
[SETUP]
 PURPOSE
The [SETUP] key accesses a menu of commonly used molbox1 functions and features that do NOT have
direct function keys. These functions include:
<1molbloc> To initialize a molbloc when it is connected to molbox1 and/or to identify the molblocs
currently connected to molbox1 (see Section 3.5.1).
<2stab>
To change the stability limit that serves as the criterion for the flow Ready/Not Ready
indication (see Sections 3.5.2 and 3.1.3).
<3adj>
To set an adder and multiplier to adjust molbox1 flow readings (see Section 3.5.3).
<4A_B>
To set molbox1 flow measurement modes that use the combination of two molblocs on
channels A and B to measure flow (see Section 3.5.4).
<5MFC>
To create, store and edit the MFC profiles used by the optional MFC function (see Sections
3.5.5 and 3.4.8).
<6reg>
To turn regulation mode of the optional MFC function ON and OFF and to set the regulation
period for the regulation mode (see Section 3.5.6).
<7flowU>
To customize the flow unit choices available under [UNIT] (see Sections 3.5.7 and 3.4.3).
<8presU>
To select/change the unit of measure in which molbox1 displays pressure values
(see Section 3.5.8).
<9tempU>
To select/change the unit of measure in which molbox1 displays temperature values
(see Section 3.5.9).
 OPERATION
To access the SETUP menu, press [SETUP] from the MAIN run
screen. The display is:
1molbloc 2stab 3adj
4A-B 5MFC 6mode ↓
7flow 8presU 9tempU
See Sections 3.5.1 to 3.5.9 for detailed information on each SETUP function.
Some screens (e.g., the SETUP menu) go beyond the two lines provided by the display. This is
indicated by a flashing arrow in the second line of the display. Press the [←] and [→] keys to move
the cursor to access the lines that are NOT visible or directly enter the number of the hidden menu
choice if you know it.
3.5.1
<1molbloc>
 PURPOSE
To initialize a molbloc when it is connected to molbox1 and/or to identify the molbloc(s)
currently connected to molbox1. To determine the gases with which a molbloc has been calibrated.
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 PRINCIPLE
molbox1 uses molbloc specific calibration information contained in the molbloc's EEPROM to
determine whether it should operate in molbloc-L or molbloc-S mode and in its calculation of
flow through the molbloc. For the molbox1 to correctly calculate the flow through the molbloc,
the molbox1 must use information on the currently active molbloc. molbloc EEPROM information
is read and stored by molbox1 in the molbox1 power up sequence when molbox1 is turned
on by selecting [SETUP], <1molbloc>.
The <1molbloc> function should be used each time there is a change in the molbloc
connected to a channel to assure that molbox1 uses the correct molbloc information on
subsequent measurements. The <1molbloc> function can also be used to display identifying
information on the molblocs currently connected to the molbox1 channels and to determine
the gases with which the molbloc has been calibrated.
 OPERATION
To access the molbloc function press [SETUP],and <1molbloc>. The function activates for
both channels without additional prompts or entries.
To view the gases with which the molbloc is calibrated, press [ENTER] in the molbloc
identification screen to view the molbloc’s gas list. After viewing, press [ESCAPE] to return
to the current run screen.
3.5.1.1
molbloc-L AND molbloc-S SIZE AND RANGE
DESIGNATIONS
Until mid-1999, molbloc-L elements (molbloc-S was not available at the time)
were always identified by “Range”. The molbloc-L “Range” is the molbloc’s
nominal full scale flow in Nitrogen (N2) at an operating pressure of 250 kPa.
Actual molbloc ranges change with the molbloc pressure dependent calibration
type and gas (see Section 1.2.5.1.1). Since mid-1999, in addition to nominal range,
molbloc-L elements have been designated by size with a sizing code (see Table 23).
On molbloc EEPROMs, the molbloc is still identified by its nominal range rather
than by its size. The identification of the molbloc displayed by [SETUP],
<1molbloc> identifies molbloc-L by both its nominal range and sizing code.
molbloc-L size and range designation correspondence are given in Table 23.
Table 23. molbloc-L Size and Nominal Range Designations
molbloc
“NOMINAL
RANGE”
DESIGNATION
© 1995 - 2007 DH Instruments, a Fluke Company
molbloc-L SIZE
DESIGNATION
10 sccm
1E1
50 sccm
5E1
100 sccm
1E2
200 sccm
2E2
500 sccm
5E2
1 slm
1E3
5 slm
5E3
10 slm
1E4
30 slm
3E4
100 slm
1E5
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3. OPERATION
molbloc-S elements are also identified by size designations, each of which relate
to a specific molbloc-S KF value. molbloc-S flow ranges depend on calibration
type and the pressure limitations of the application and molbox used. For information
on the possible molbloc-S flow ranges with various operating pressures, see
Section 1.2.5.2.2). molbloc-S size and KF value correspondence are given in Table 24.
Table 24. molbloc-S Size and Pressure to Flow Conversion Ratio (KF)
KF
(sccm/kPa)
3.5.2
molbloc-S SIZE
DESIGNATION
50
5E1-S
100
1E2-S
200
2E2-S
500
5E2-S
1 000
1E3-S
2 000
2E3-S
<2STAB>
 PURPOSE
To change the stability limit that serves as the criterion for the flow Ready/Not Ready
indication (see Section 3.1.3).
 PRINCIPLE
molbox1 continuously monitors the rate of change of flow through the molbloc to which it is
connected and compares this rate to the stability limit to make a Ready/Not Ready
determination (see Section 3.1.3). The STABILITY function allows the stability limit to be
adjusted by the user to increase or decrease the stability required for a Ready (<*>) condition
to occur.
The default stability limit is + 0.1 sccm/second (or equivalent in another flow unit).
The stability limit value is automatically converted when the flow unit of measure
is changed.
The stability limit is separate and different from the RATE DISPLAY function
(see Section 3.4.6.1) which allows the current rate of change of flow to be displayed.
 OPERATION
To adjust the stability limit press [SETUP] and select <2stab>. The display is:
1.
Entry field for setting the desired stability limit in the current
flow unit of measure. Recalls the default stability limit or the
last stability limit set.
Flow stability test:
0.1 sccm/s
Edit the stability limit setting as desired. Pressing [ENTER] activates the stability limit for the
range and returns to the current run screen.
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The stability limit value is automatically converted when flow units of measure
are changed.
The [RES] setting affects the resolution of the stability limit value. If the stability limit
display does not have enough resolution to set the desired value, use [RES] to adjust the
resolution (see Section 3.4.9).
3.5.3 <3ADJ>
 PURPOSE
To apply adder (FA) and multiplier (FM) coefficients to the flow measured by the molbox1.
PRINCIPLE
The ADJ function gives the user the capability to adjust mass flow readings made by the molbox1.
This is accomplished by setting an adder and a multiplier.
The adder (FA) and multiplier (FM) adjust the displayed value of the flow through the molbloc
as calculated by the molbox RFM following:
corrected flow = (calculated flow * FM) + FA
If a K factor is active (see Section 3.4.1), the adder and multiplier are applied to the
calculated flow before the K factor is applied.
Using the Flow ADJ Function with molbloc-L to Handle a Gas Mixture
The flow ADJ function can be used to adjust flow readings to measure a gas mixture if the
molecular weight and relative content of each component gas is known. Note that this
method does not take into account the true viscosity, compressibility or critical flow coefficient
factor of the gas mixture. The thermodynamic properties of only the highest concentration
gas are used. Therefore, the uncertainty in the measured flow is increased and the method
is best when the highest concentration gas is greater than 90% of the mixture.
To use this feature, set the molbox1 [GAS] (see Section 3.4.2) to the highest concentration
gas, then adjust the flow multiplier by:
molecular weight of the mix
molecular weight of the gas selected on the molbox
For example, to adjust a gas mix that is 95 % Nitrogen (N2) and 5 % Oxygen (O2):
n Calculate the molecular weight of the mix.
N2 molecular weight = 28.016
O2 molecular weight = 31.999
Mix molecular weight = (28.016 x 0.95) + (31.999 x 0.05) = 28.215
o Select N2, the highest concentration gas, as the molbox1 gas.
p Calculate:
molecular weight of the mix
molecular weight of the gas selecton on the molbox
q Set flow multiplier in ADJ function to 1.0071.
© 1995 - 2007 DH Instruments, a Fluke Company
Page 84
=
28.215
28.016
= 1.0071
3. OPERATION
 OPERATION
To access the ADJ function press [SETUP] and select
<3adj>. The display is:
Adder: 0
sccm
Mult: 1.00000
Edit the values as desired. Pressing [ENTER] returns you to the MAIN run screen with the
edited adder and multiplier values applied.
The adder is expressed in current flow units and is NOT automatically converted when flow
units are changed. Adder values must be entered in the current flow units. The multiplier
is dimensionless.
The flow adder and multiplier of the ADJ function, if different from 0 and 1, alter the flow
readings made by the molbox1. The ADJ function is always "ON" with no indication on the
run screen of the current adder and multiplier values. When using adders and multipliers,
great caution should be taken to ensure that they are entered and changed correctly and
that they are 0 and 1 if no adder or multiplier effect is desired.
3.5.4
<4A_B>
 PURPOSE
To turn ON and OFF special molbox1 operating modes that use molbox1 channels A and B together.
 PRINCIPLE
There are two A_B modes. In both of these modes molbox automatically switches between
the molblocs on its two channels and uses readings from both. The two A_B modes are:
•
Additive mode (A+B) (see Section 3.5.4.2).
The additive mode sums the flow on channels A and B. It is designed for using two molblocs
in parallel to measure flows greater than the maximum flow range of a single molbloc.
•
Ratiometric mode (A/B) (see Section 3.5.4.3).
The ratiometric mode determines the ratio of the flow through two molblocs. This can provide
a convenient, system controlled, method for comparing molblocs to determine the coherence
between different ranges.
3.5.4.1
GENERAL OPERATION (ASPECTS COMMON TO BOTH
A_B MODES)
To access A_B modes, press [SETUP], <4A_B> and select the desired mode
(<1A+B>, <2A/B>). Once the mode is selected, molbox1 returns to the MAIN
run screen with the selected mode active. An indication of the active A_B mode
will be in the lower right of the MAIN run screen when space is available. To cancel
operation of an A_B mode, press the [A/B] function key (see Section 3.4.7) and
operation returns to normal single channel mode.
When operating in an A_B mode, channel A is the dominant channel so the
channel specific functions applied (gas, flow unit, stability test, K factor, etc.)
will be those currently selected for channel A. Tare and leak check still apply to
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each channel individually. Purge automatically purges channel A and then
channel B (see Section 3.4.4).
When in an A_B mode, the channel indicator LED switches between channels showing
the channel that is currently active. The P&T function displays (see Section 3.4.5)
also switch as molbox1 switches from channel to channel to display values for
the currently active channel.
In an A_B mode, molbox1 reads on one channel until either a Ready reading is
obtained or for up to 10 seconds, whichever comes first. If the last two single
channel readings were Ready, the A+B or A/B result is displayed as Ready. If one
or both of the last two single channel readings was Not Ready, the A+B or A/B
result is displayed as Not Ready (see Section 3.1.3).
It is helpful to set the molbox1 stability setting as low as is practical in any
A_B mode to allow for flow stabilization on each channel. To change the
molbox stability setting, select [SETUP], <2stab> (see Section 3.5.2).
In A_B mode operation, molbox1 may stay on one channel up to 10 seconds
waiting for a Ready reading. The first valid reading after entering A_B mode
may require 20 seconds and subsequent readings up to 10 seconds.
It is not possible to operate A_B modes when the active BPR mode is Auto
due to internal valving conflicts. molbox1 will deny access to the A_B modes
if the current BPR mode is Auto and will not allow the user to select Auto
mode when an A_B mode is active (see Section 3.6.9).
3.5.4.2

A+B MODE
PURPOSE
To operate two molblocs simultaneously on molbox1 channels A and B and
obtain a flow rate which is the sum of the flow through the two molblocs.

PRINCIPLE
In A+B mode molbox1 makes measurements on one channel and then the
other channel. The flow rate displayed is the sum of the two most recent channel
readings, updated each time a channel reading is complete. This allows two
molblocs to be used together in parallel to measure flows greater than the range
of a single molbloc.

SET UP
Best results with A+B mode are obtained when the two molblocs are mounted in
parallel, symmetrically. A common regulator should be used with as little tubing,
fittings, etc., as possible between the point where flow is split upstream of the two
molblocs and rejoined downstream. Standard hardware setups (molstics) for
A+B operation are available from DHI.
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3. OPERATION

OPERATION
To activate A+B mode, press [SETUP], select <4A_B> and then select <1A+B>.
molbox1 returns to the MAIN run screen in A+B mode. The MAIN run screen in
A+B mode is:
1.
Ready/Not Ready indication.
2.
Sum of channel A and channel B's two most
recent flow rate readings and the unit of flow.
3.
The gas that is being flowed.
4.
Rate of change of flow for the A+B results in
units of flow per second.
5.
Indication that A+B mode is active (if space is
available).
* 45.0775 slm N2
R 0.002/s A+B
The MFC run screens (if the molbox1 has the optional MFC control feature) are
unchanged except that the top line indications are A+B flow.
3.5.4.3

A/B MODE
PURPOSE
To operate two molblocs simultaneously on molbox1 channels A and B and
display the ratio of their flow rates.

PRINCIPLE
In A/B mode, molbox1 makes measurements on one channel and then the
other channel. The individual flow rate measured by each channel is displayed
as it is read and information on the ratio and disagreement between the two
channels is also calculated and displayed.
This function is intended to provide a convenient, system controlled, means of
comparing two molblocs, for example to check the coherence of measurements
made by different molblocs.

SET UP
When using A/B mode to compare two molblocs, the two molblocs are connected
in series. The volume between the two should be minimized and the upstream
pressure regulation should be as stable as possible to facilitate the establishment
of the steady state flow condition that must exist for a valid comparison to be made.
When selecting the hardware setup for running an A/B mode comparison, it is
important that the resulting setup allows each molbloc to operate under the
correct pressure conditions for that molbloc’s calibration type. It is helpful to set
the molbox1 stability setting as low as is practical in any A_B mode to allow for
flow stabilization on each channel. To change the molbox1 stability setting,
select [SETUP], <2stab> (see Section 3.5.2).
A/B operation is not recommended with 1E5 molblocs due to their low
differential pressure range.
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
OPERATION
To activate A/B mode, press [SETUP], select <4A_B> and then select <2A/B>.
molbox1 returns to the MAIN run screen in A/B mode. The MAIN run screen in
A/B mode is:
1.
Ready/not ready indication.
2.
Last flow measurement on currently active
channel with flow unit.
3.
The gas that is being flowed.
4.
The ratio of the two most recent channel
readings (A/B).
5.
The difference in percent between the two
most recent channel readings.
* 101.305 sccm N2
A/B 0.99803 D-01.97%
Though the optional MFC control functions are still active in A/B mode, the MFC
run screens are not available.
To return to single channel mode, use the A/B function to select either A or
B molbloc.
3.5.5
<5MFC>
 PURPOSE
To create, store and edit the MFC profiles used by the optional MFC control function (see Section 3.4.8).
The MFC control function is an optional feature of molbox1. If this option was not ordered
with the molbox1, the 1mfc function of the SETUP menu will not be active.
 PRINCIPLE
MFC profiles are used by molbox1 to configure the MFC function. MFC profiles define the
analog signal range of the MFC and the relationship between the analog signal range and the
flow range of the MFC. This information allows molbox1 to operate with the correct signal for
the current MFC and to convert the MFC analog signals to the corresponding flow or % FS
values when desired.
MFC profiles are set up using [SETUP], <5MFC>. MFC profiles are stored by molbox1 under
profile numbers. This profile number is used to select the MFC profile when the MFC
function is activated using the MFC function key (see Section 3.4.8). Up to 26 MFC profiles
can be defined and stored.
MFC profiles are designed to allow the user to set up the profiles of the MFCs typically
calibrated by or used with molbox1 so that they can be conveniently recalled from a lookup
table when needed.
MFC profiles #1 and #2 are factory profiles and cannot be edited. Profile #1 sets the MFC
control option to work in Volts with no flow range specified. Profile #2 sets the MFC control
option to work in milliamps with no flow range specified.
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3. OPERATION
 OPERATION
To create or edit an MFC profile, press [SETUP], <5MFC>.
Enter profile number
#4
The display is:
Select the profile number to edit and press [ENTER].
MFC profiles #1 and #2 are factory default profiles for working with the MFC function
directly in analog units without specifying MFC flow range or units. Profile #1 is 0 to 5 V,
profile #2 is 4 to 20 mA (see Sections 3.4.8, 3.5.5).
Input type:
1voltage
2current
The display is:
Select the analog signal type of the MFC and press [ENTER].
The next display is used to enter the full scale voltage or current. Enter the full scale voltage
of current of the MFC and press [ENTER]. If the MFC signal selected was current (mA), you
are also be prompted to enter the MFC 0 flow current output. molbox1’s MFC control
function does not support mixed current/voltage MFCs.
The next selection specifies the flow units of measure
for this MFC profile. See Section 3.4.3 for an explanation
of the unit selections.
Flow unit 1std 2user
3perfect
After the flow unit of measure has been selected the
display prompts for the range which will be entered in
the previously selected units. Enter the numerical
value of full scale of the MFC in flow units.
Enter range
100.000 sccm
The next selection specifies whether the device is a
mass flow meter that measures flow only (MFM) or a
mass flow controller (MFC). Choose <1MFM> if the
device for this profile measures only, choose <2MFC>
if the device measures and controls flow.
Device Type
1measure
2control
Once the device type has been selected, editing is complete and a prompt to edit the next
profile # is presented. Pressing [ESCAPE] returns to the MFC function. Pressing [ESCAPE]
again returns to the current run screen.
To clear/reset all MFC profiles, except #1 and #2 factory default profiles, use [SPECIAL],
<1reset>, <3mfc>.
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3.5.6
<6REG>
 PURPOSE
To turn the MFC control regulation mode ON and OFF and to set the regulation period for
regulation mode.
The REGE function affects the molbox1 MFC control function. The MFC control function is
an optional feature. If this option is not installed in the molbox1, the REG function of the
SETUP menu is not active.
 PRINCIPLE
Regulation mode is designed to allow an MFC to be used with molbloc/molbox to precisely
set flows as measured by the molbloc/molbox. This feature allows an MFC to be used to
control flows to specific values as measured by the molbloc/molbox.
When the molbox1 MFC function is active, set points can be sent to the MFC. In normal
operation, the set point entered is the set point signal sent to the MFC and that set point is
held constant until a new set point is given. The molbloc/molbox is used to read the flow
resulting from that MFC setpoint.
Regulation mode allows a set point to be given in terms of the desired flow through the
molbloc as measured by the molbox1. In regulation mode, the molbox1 regularly readjusts
the actual set point applied to the MFC as needed to adjust flow to the desired flow value
through the molbloc. At each regulation cycle, the molbox1 corrects the set point to the MFC
based on the difference between actual flow through the molbloc and the desired flow.
The regulation period sets the time interval between each regulation cycle.
If there is a significant volume between the molbloc and the MFC, regulation will be
improved by increasing the regulation period.
 OPERATION
To activate or deactivate regulation mode and to set the regulation period, press [SETUP]
and select <6reg>.
Regulation Period
(0 disables): 0
The display is:
If 0 (zero) is entered, regulation mode is inactive. If a value greater than 0 (zero) is entered,
regulation mode is activated and the regulation period is value entered in seconds.
Maximum regulation period: 99 seconds
Minimum period: Single channel operation:
A+B Mode:
2 seconds
10 seconds
Typical effective regulation period: Single channel operation:
A+B Mode:
5 seconds
20 seconds
When the regulation mode is active, <R> is displayed in the bottom right hand corner of the
MAIN run screen (when space is available).
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3. OPERATION
3.5.7 <7flowU>
 PURPOSE
To customize the selection of flow units of measure that are available for selection from the
[UNIT] function key (see Section 3.4.3).
 PRINCIPLE/OPERATION
See Section 3.4.3.5.
3.5.8 <8presU>
 PURPOSE
To select/change the unit of measure in which molbox1 displays pressure values.
 OPERATION
To set the unit of measure in which molbox1 displays pressure values, press [SETUP] and
select <8presU>.
Pressure unit type:
1SI 2other 3user
The display is:
Select the unit type desired, then select the unit desired. After the unit selection, operation
returns to the run screen with the selected pressure unit of measure active.
The pressure units of measure available are listed in Table 25.
Table 25. Pressure Units of Measure Available
<1SI>
<2Other>
<3User>*
<1Pa>
<1psi>
<1user>
<2kPa>
<2psf>
<3mPa>
<3inHg>
<4mbar>
<4inWa>
<5bar>
<5kcm2>
<6mmHg>
<7mmWa>
*3User: User defined unit.
The “user” unit is defined in terms of user units/Pa when the user unit is selected.
See Section 7.1.1 for definition of the pressure unit conversions used by molbox1.
3.5.9 <9tempU>
 PURPOSE
To select the unit of measure in which molbox1 displays temperature values.
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 OPERATION
To set the unit of measure in which molbox1 displays temperature values, press [SETUP]
and select <9tempU>.
Temperature unit:
1celcius 2fahrenheit
The display is:
Select the desired unit. After the unit selection, operation returns to the run screen with the
selected temperature unit active.
See Section 7.1.2 for definition of the temperature unit conversions used by molbox1.
3.6
[SPECIAL]
 PURPOSE
The [SPECIAL] key accesses a menu of molbox1 functions and settings that are less commonly or not
normally used in regular operation. These functions include:
<1reset>
Access and execute various reset options (see Section 3.6.1).
<2level>
Set user protection levels that restrict access to certain functions and to edit the user
password (see Section 0).
<3ul>
Set upper pressure limit alarm (see Section 3.6.3).
<4cal>
View and adjust the molbox1 pressure transducers, reference resistors and MFC analog
option (see Section 3.6.4).
<5prefs>
Set display screen saver time, unit ID number and date and time (see Section 3.6.5).
<6remote> View and edit molbox1 COM port (RS232) and IEEE-488 interface settings (see Section 3.6.6).
<7drivers> Control the on/off of molbox1’s optional 12 V drivers (see Section 3.6.7).
<8head>
Set the height for the pressure fluid head correction (see Section 3.6.8).
<9BPR>
Set back pressure ratio (BPR) mode (molbloc-S operation only) (see Section 3.6.9).
 OPERATION
To access the SPECIAL menu, press [SPECIAL] from the MAIN run screen.
1reset 2level 3ul
4cal 5prefs 6remote ↓
7drivers 8head 9BPR
The display is:
Select the desired function.
See Sections 3.6.1 to 3.6.9 for detailed SPECIAL function descriptions.
© 1995 - 2007 DH Instruments, a Fluke Company
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3. OPERATION
Some screens (e.g., the SPECIAL menu) go beyond the two lines provided by the display. This is
indicated by a flashing down arrow in the second line of the display. Press the [←] and [→] keys to
move the cursor to access the lines that are NOT visible or directly enter the number of the hidden
menu choice if you know it.
3.6.1
<1RESET>
 PURPOSE
To reset various molbox1 settings to default or factory values.
 PRINCIPLE
molbox1 stores its user definable settings in non-volatile memory. The reset menu allows the
user to selectively or completely reset these settings to factory defaults. Reset clears
settings that the user may have made, and should be used only to restore the molbox1 to a
known state. molbox1 will go through its reboot routine after any type of reset is executed.
 OPERATION
To access the reset choices press [SPECIAL] and
select <1reset>. The display is:
1sets 2units 3mfc
4cal 5all
Select the desired reset. After confirmation, the reset occurs. A reset always puts the
molbox1 through its start up routine as if power had been turned OFF and back ON.
See Sections 3.6.1.1 through 3.6.1.5 for detailed information on the specific reset choices.
RESET functions change user settings that affect flow measurement. If not used
properly, resetting can cause out of tolerance measurements. RESET functions should
only be used by qualified personnel with reference to this manual for information on the
RESET functions.
3.6.1.1

<1SETS>
PURPOSE/OPERATION
To access Reset - Sets, press [SPECIAL] and select <1reset>, <1sets>.
Reset - Sets clears and sets to default the user settings for various measurements.
These include:
•
Flow unit of measure to sccm (see Section 3.4.3).
•
Pressure unit of measure to kPa (see Section 3.5.8).
•
Temperature unit of measure to °C (see Section 3.5.9).
•
Gas type to N2 (see Section 3.4.2).
•
Stability criterion to 0.1 sccm (see Section 3.5.2).
•
K factor to 1 (see Section 3.4.1).
•
DISPLAY function to Rate (see Section 3.4.6.1).
•
RPT Tare value to 0 (see Section 3.4.4.1.1).
•
Tare to upstream pressure (see Section 3.4.4.1.1).
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•
Flow adder to 0 and flow multiplier to 1 (see Section 3.5.3).
•
Resolution to 0.001 % (see Section 3.4.9).
•
BPR mode to Auto (see Section 3.6.9)
3.6.1.2

<2UNITS>
PURPOSE/OPERATION
To access Reset - Units, press [SPECIAL] and select <1reset>, <2units>.
Reset - Units clears and sets to default all UNIT OF MEASURE functions. These include:
•
Six flow units of measure selectable from [UNIT] to defaults (see Section 3.4.3).
•
Flow unit of measure to sccm (see Section 3.4.3).
•
Reference temperature for uxxx units of measure to 0 °C (see Section 3.4.3.3).
•
Volume flow unit of measure conditions to molbloc for temperature and
standard atmospheric pressure for pressure (see Section 3.4.3.4).
•
Pressure unit of measure to kPa (see Section 3.5.8).
•
User pressure unit coefficient to 1.00/Pa (see Section 3.5.8).
•
Temperature unit of measure to °C (see Section 3.5.9).
3.6.1.3

<3MFC>
PURPOSE/OPERATION
To access Reset - MFC, press [SPECIAL] and select <1reset>, <3MFC>.
Reset - MFC clears and sets to default all functions associated with the optional
analog MFC control. These include:
•
Set MFC channel to 0 (inactive) (see Section 3.4.8).
•
Set regulation mode to OFF (see Section 3.5.6).
•
Set MFC profile to 1 (see Section 3.4.8.2).
•
Clear/delete user defined MFC profiles (see Section 3.5.5).
3.6.1.4

<4CAL>
PURPOSE/OPERATION
Use special caution with this reset as critical calibration data may be altered.
To access Reset - Cal, press [SPECIAL] and select <1reset>, <4cal>.
Reset - Cal clears and sets to default the user calibration coefficients for molbox1
Reference Pressure Transducers (RPTs) (see Section 5.2). This includes:
•
Upstream and downstream absolute RPTs:
Adder
0
Multiplier:
1
Calibration Date: 19980101
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3. OPERATION
Reset - Cal has NO effect on the reference resistance values used to calibrate
molbox1s internal ohmic measurement system (see Section 5.4) or on the
calibration coefficients for the optional MFC control function (see Section 3.4.8).
3.6.1.5

<5ALL>
PURPOSE/OPERATION
To return molbox1 to the original, as delivered factory condition. Performs the
SETS, UNITS, CAL and MFC RESET functions and resets all other settable
values to defaults. This includes communications port settings.
To access Reset - All, press [SPECIAL] and select <1reset>, <5all>.
Use special caution with this reset as critical calibration data may be altered.
3.6.2
<2LEVEL>
 PURPOSE
To set user protection levels that restrict access to certain functions and to edit the password
required for changing user levels.
 PRINCIPLE
molbox1’s front panel user interface provides the means to access all molbox1 user d efined
d a ta , se ttin gs and func tio ns incl ud in g c al ib ra tion d a ta . Inadvertent, uninformed
or unauthorized altering or deleting of data, settings and functions could require extensive
reconfiguration by the user and might cause invalid readings. For these reasons, depending
upon the application in which molbox1 is being used, it may be desirable to restrict access to
certain functions. The USER LEVEL function makes this possible. Four different levels of
security are available: none, low, medium and high.
Access to changing security levels can be left open, or be protected by a password so that
security levels can be used as a convenient way to avoid accidental changing of data or as a
secured means of preventing tampering with molbox1 settings.
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3.6.2.1
SECURITY LEVELS
The security levels are structured to support typical operating environments as follows:
None
This level is intended for use only by the system manager and/or
calibration facility. It allows access and editing in all areas including
critical metrological in fo r ma t io n a nd o t her s e t t in gs t h a t
a ffec t measurement integrity.
Low
Low security is designed to protect the specific metrological
information and SYSTEM DIAGNOSTIC AND MAINTENANCE
functions of the system against accidental alteration. It is intended for
an advanced operator performing many different tasks. Low security
is the default user level setting.
Medium
Medium security is designed to protect specific metrological
information in the system and to assure that the molbox1 is operated
using consistent operational parameters.
High
High security protects all operating parameters. It is intended to
minimize operator choices (e.g., to perform repeated identical tests
under consistent conditions).
molbox1 is delivered with the security level set to low to avoid inadvertent
altering of critical internal settings but with unrestricted access to changing
security level setting. It is recommended that the low security level be
maintained at all times and password protection be implemented if control
over setting of security levels is desired.
If there is a risk of unauthorized changing of the security level, changing
authority should be password protected (see OPERATION of this section).
The High security level disables remote communications and returns an error
message (“ERROR”) to all remote commands. All other security levels have
NO effect on remote communications.
The security levels are structured to support typical levels of operation.
Specifically, the security levels prevent execution of the functions accessed by
the key strokes marked by “•” in Table 26.
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3. OPERATION
Table 26. Security Levels - Functions NOT Executed Per Function/Level
KEYS
LOW
MEDIUM
HIGH
[K]
•
[GAS]
•
[UNIT]
•
•
[UNIT] (change temperature/pressure conditions)
•
•
[TARE] (access menu)
•
[TARE], <1tare>, <select tare pressure>
•
[TARE], <2purge> change purge time
•
•
[TARE], <4AutoZ>, <4run>
•
•
[P&T]
•
[DISPLAY]
•
•
[DISPLAY] (change times/target)
•
•
[A/B]
[MFC]
•
[RES]
•
•
•
[SETUP], (access to menu)
•
[SETUP], <1molbloc>
•
•
•
•
•
[SETUP], <4A_B>
•
•
[SETUP], <5MFC>
•
•
[SETUP], <6mode>
•
•
[SETUP], <7flowU>
•
•
[SETUP], <8presU>
•
•
[SETUP], <9tempU>
•
•
[SPECIAL], <1reset>
•
•
[SPECIAL], <1reset>, <1sets>
•
•
[SPECIAL], <1reset>, <2units>
•
•
[SETUP], <2stab>
•
[SETUP], <3adj>
[SPECIAL], <1reset>, <3MFC>
•
•
•
[SPECIAL], <1reset>, <4cal>
•
•
•
[SPECIAL], <1reset>, <5all>
•
•
•
•
[SPECIAL], <3UL>
•
•
•
•
•
•
[SPECIAL], <5prefs>
•
•
[SPECIAL], <5prefs>, <1ScrSvr>
•
•
[SPECIAL], <3UL> (change setting)
[SPECIAL], <4cal>
[SPECIAL], <4cal>, <any 3edit>
•
[SPECIAL], <5prefs>, <2ID>, <2edit>
•
•
•
[SPECIAL], <5prefs>, <3time> (make changes)
•
•
•
•
[SPECIAL], <6remote>
[SPECIAL], <6remote> (changes settings)
•
•
[SPECIAL], <7drivers>
•
•
Remote communications disabled
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MOLBOX1™ OPERATION AND MAINTENANCE MANUAL

OPERATION
molbox1 is delivered with NO active password so access to the User Level
menu is open. The user level is set to <1Low>. User levels can be changed
freely until a password has been created. RESET functions (see Section
3.6.1) do not affect the password setting.
To access the USER LEVEL function, press [SPECIAL], <2level>.
If NO password yet exists or if the
correct password has been entered,
the display is:
1change user level
3edit password
Selecting <1change user level> brings
up the restriction menu:
Restriction: 1none
2low 3medium 4high
Select the desired restriction level, or press [ESCAPE] to return to the current
run screen.
Selecting <2edit password> displays the
user password and allows it to be edited.
Passwords can be up to six numbers in
length and cannot start with a zero.
Password: pppppp
0 disables password
If 0 is entered as the password value, then the password is made inactive and a
password will NOT be required to access the user level menu. This is the factory
default with a security level of <2low>.
Once a password has been entered, the user level cannot be changed without
reentering the password.
If there is an active password, the molbox1 password entry screen appears.
The user must enter the user defined
password or the factory secondary
password to proceed. When a password
is entered correctly, operation proceeds to
the
<1change
user level
2edit
password> screen.
RFM SN
Password:
nnn-xx
pppppp
The first field, <nnnn>, is the serial number of the molbox1, followed by a
second field, <xx>, that counts the number of times that a secondary password
has been used. The second field increments each time a secondary password
is used. The third field, <pppppp>, is for normal password entry.
The factory secondary password is available in case the user password has
been misplaced or forgotten. A factory secondary password can be obtained by
contacting a DHI Authorized Service Provider (see Section 7.4). The factory secondary
password is different for each molbox1 and changes each time it is used.
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3. OPERATION
3.6.3 <3UL>
 PURPOSE
To set an upper pressure limit above which molbox1 will produce a warning, interrupt
operation and isolate its internal pressure transducers.
 PRINCIPLE
molbox1 contains two, high precision reference pressure transducers (RPTs). These can be
fatally damaged by large overpressures. The UL function uses molbox1's internal capabilities
to attempt to protect the RPTs against overpressure. molbox1 continuously monitors the
pressure read by the RPTs. When the pressure passes the level set by the UL function,
molbox1 warns the operator by sounding an audible alarm. Beyond the UL limit there is an
overpressure limit, which is not user selectable. If the pressure reaches the overpressure
limit, molbox1 uses its internal valves to isolate the RPTs.
 OPERATION
To access the Upper Limit (UL) function, press [SPECIAL], <3ul>. The display is:
The indication is of the current upper limit setting in
the current pressure unit of measure. To specify a
different pressure unit of measure, use [SETUP],
<8presU> (see Section 3.5.8).
Transducer Max Pres:
600.000 kPaa
To change the upper limit, enter the value desired (see max UL limits below) and press
[ENTER]. The display returns to the MAIN run screen with the new upper limit in effect.
The maximum upper limit settings, which are also the default values, are 5 % above the
molbox1 maximum operating pressure ranges. For the two molbox1 models, the max UL
values are specifically:
For molbox1 A350K:
262.5 kPa absolute (38 psia)
For molbox1 A700K:
630 kPa absolute (91 psia)
The molbox1 overpressure limits, which cannot be edited, are:
For molbox1 A350K:
275 kPa absolute (40 psia)
For molbox1 A700K:
660 kPa absolute (96 psia)
If the overpressure limit is exceeded, all molbox1 internal valves close and normal operation
is interrupted. Normal operation can be reestablished by turning molbox1's power OFF and
back ON or pressing [ENTER]. Be sure to correct the situation that led to the overpressure
condition prior to rebooting molbox1 or pressing [ENTER]. See Sections 3.6.3.1, 3.1.4 for
additional details.
UL is molbloc channel specific. There are separate UL settings for molbloc channel A and
channel B operation.
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3.6.3.1
UPPER LIMIT ALARM AND SEQUENCE
When the pressure reaches the upper limit, molbox1 continues normal operation
but sounds an audible alarm. The alarm ceases if the pressure is decreased
below the upper limit.
When pressure reaches the overpressure
limit, all molbox1 internal valves close,
normal operation ceases and the display
indicates:
610.250 kPa 601.780
OVERP! CHK & PWR DWN
The top line indicates the current pressure measurement of the upstream (left)
and downstream (right) RPTs. The bottom line is the over pressure warning.
Pressure indications that are grossly out of scale generally indicate that the
RPT(s) have been fatally over pressured.
Other menus can be observed but the MAIN run screen can not be accessed and
no molbox1 internal valves can be operated. To return the molbox1 to normal
operation, it must be turned OFF and back ON or press [ENTER] from the
overpressure screen. When molbox1 normal operation is reestablished, its isolation
valves will open. Be sure the situation that led to the overpressure condition is
corrected before attempting to reestablish normal operation.
The upper limit and overpressure functions are intended to use molbox1's
features to the extent possible to protect the molbox1 reference pressure
transducer (RPTs) against overpressure. The system is not failsafe and an
overpressure causing fatal damage to the RPTs can still occur. Ultimately,
protection of the RPTs is the responsibility of the user. RPTs damaged by
overpressure are not covered under the product warranty.
molbox1 continuously monitors for maximum pressure. Whenever the
overpressure limit is exceeded, the pressure value reached, time and date are
logged to a privileged location. This information can be of use in determining
the events that led to an overpressure situation.
3.6.4
<4CAL>
To calibrate and adjust the molbox1 reference pressure transducers, ohmic measurement
system and optional MFC control function.
The CALIBRATION functions are considered part of molbox1 maintenance and are therefore
covered in the maintenance section of this manual (see Section 5).
3.6.5
<5PREFS>
 PURPOSE
To access a menu of molbox1 internal operational preferences and functions. These include:
<1ScrSvr> View and change the SCREEN SAVER function (see Section 3.6.5.1).
<2ID>
View and edit the molbox1 user ID (see Section 0).
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3. OPERATION
<3time>
View and edit the internal time and date settings (see Section 0).
 OPERATION
To access the PREFS menu press [SPECIAL], and
select <5prefs>. The display is:
1ScrSvr 2ID 3time
Select the desired function.
See Sections 3.6.5.1 to 0 for detailed information on each PREFS function.
3.6.5.1

<1SCRSVR>
PRINCIPAL
To adjust the time setting of molbox1’s SCREEN SAVER function.

PRINCIPAL
molbox1 has a SCREEN SAVER function which causes the display to dim after a
front panel key is NOT pressed for a certain amount of time. The default screen
saver time activates the screen saver after 10 minutes. The screen saver activation
time can be adjusted by the user or screen saving can be completely eliminated.

OPERATION
To access the SCREEN SAVER function, press [SPECIAL] and select
<5prefs>, <1ScrSav>. Edit the time, in minutes, after which the screen saver will
activate to dim the screen. Set zero to eliminate the SCREEN SAVER function.
Setting screen saver time to zero eliminates the SCREEN SAVER function so
that the display permanently remains at full brightness.
3.6.5.2

<3ID>
PURPOSE
To view or edit the molbox1 user ID and to view the molbox1 serial number.

PRINCIPAL
molbox1 has a factory programmed serial number that is included on the product
back panel and can be viewed in the introductory screen.
molbox1 also allows the user to store a unique, twelve character, alpha numeric
ID number. This feature is frequently used to assign an organizational control ID
(e.g., an asset number, tool number, standard number, etc.). The ID function allows the
ID number to be viewed and edited. It also displays the molbox1 factory serial number.

OPERATION
To access the ID function press [SPECIAL] and select <5prefs>, <2ID>.
Select <1view> to view the current ID.
Select <2edit> to edit the ID.
The ID has twelve characters. When the edit screen is opened, the cursor is on
the first character. Numerical values can be entered directly from the keypad.
In addition, the [←] and [→] keys can be used to toggle through a list of available
alpha numeric characters. Holding the key slews through the characters. Character order
going up ([→]) is: blank space, symbols, lower case letters, upper case letters, numbers.
After selecting a character, press [ENTER] to activate it and move to the next character field.
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When a character is selected the cursor moves to the next character. To leave a
blank character, press [ENTER] with the field for that character blank. Use this
for the trailing characters if the ID being entered is less than twelve characters.
After the last of the twelve characters has been entered, the <Save ID?> option is offered.
Select <1no> to return to the ID edit screen. Select <2yes> to save the edited ID.
The ID can be set remotely from a computer which is quite a bit more convenient
than entering characters from the keyboard (see Section 4.3.4.2, ID command).
The ID cannot be cleared or reset by any RESET functions (see Section 3.6.1).
3.6.5.3

<3TIME>
PURPOSE
To view and edit the molbox1 internal time and date settings.

OPERATION
To access the TIME function press
[SPECIAL]
and
select
<5prefs>,
<3time>. The display is:
Edit: 1time 2date
08:32:11 am 19980101
Select <1time> to edit the time. Edit hours, then minutes, then am/pm by
pressing [ENTER] at each entry. Seconds go to zero when minutes are entered.
This can be used to synchronize the time with a time standard.
Select <2date> to edit the date.
YYYYMMDD format.
The date must be specified in
The molbox1 date and time are set to United States Mountain Standard
Time in the final test and inspection process at the factory. If desired, use
the TIME and DATE functions to set your local time and date.
3.6.6
<6REMOTE>
 PURPOSE
To configure the molbox1 COM1, COM2 and IEEE-488 communication ports. To test COM1
and COM2 communications.
 PRINCIPLE
The molbox1 has two RS232 communications ports referred to as COM1 and COM2 and a
single IEEE-488 port. COM1 and the IEEE-488 port are for communicating with a host
computer (see Section 4.1). COM2 is reserved for pass through communications with an
external device, (e.g., a multimeter, second molbox, MFC controller, etc.). These ports can
be set up from the molbox1 front panel.
molbox1 provides a self-test for its RS232 communication ports. The self-test allows
verification that the molbox1 RS232 ports (COM1 and COM2) are operating properly and that
a valid interface cable is being used.
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3. OPERATION
 OPERATION
To access the communication port configurations, press [SPECIAL] and select <6remote>.
Select <1COM1>, <2COM2>, or <3IEEE-488> to view and/or edit that port’s settings.
To access the RS232 self-test press [SPECIAL] and select <6remote>, <4RS232test>.
3.6.6.1
COM1 AND COM2
The COMx port settings can be adjusted. The settings are baud rate, parity, data
bits and stop bits. The available options are listed in Table 27.
Table 27. COM1 and COM2 Available Settings
BAUD RATE
300, 600, 1 200, 2 400, 4 800, 9 600, 19 200
PARITY
NONE, ODD or EVEN
DATA BITS
7 or 8
STOP BITS
1 or 2
The default COMx settings are 2400, E, 7,1 for both COM ports.
The molbox1 appends a carriage return (<CR>) and a line feed (<LF>) to all
messages that are sent out of the COM1 port to the host. It looks for a carriage
return to terminate incoming messages and ignores line feeds. The user MUST
wait for a reply to each message sent to the molbox1 before sending another
message to it (see Section 4.2.1).
3.6.6.2
IEEE-488
The IEEE-488 port address can be defined from 1 to 31. The default address is 10.
The molbox1 sends a line feed (<LF>) and asserts the EOI line at the end of all
transmitted messages. It looks for a line feed and/or assertion of the EOI line to
terminate incoming messages (see Section 4.2.2).
3.6.6.3
RS232 SELF-TEST
The RS232 self-test is provided to check the molbox1 COM ports and the
interface cable independently of an external device or computer.
If you are having difficulty communicating with molbox1 from a host
computer using RS232, the RS232 self test can help establish that the molbox1
COM1 port you are trying to communicate with and the interface cable you are
using are good.
To run a self test of the RS232 ports (COM1 and COM2), press [SPECIAL] and
select <6remote>, <4RS232test>.
The display prompts you to connect COM1 to COM2 using a standard pin to pin
DB-9F to DB-9M RS232 cable (see Section 4.2.1.1).
Once the cable has been installed, press [ENTER] to run the self-test. The test
is first executed in the COM1→COM2 direction and then in the
COM2→COM1 direction.
If the COM1→COM2 test passes: <PASSED> displays briefly and the test
proceeds to COM2→COM1.
If COM2→COM1 passes: <PASSED> is displayed briefly followed by the
conclusion, <molbox1 RS232 test has PASSED>.
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If a test fails: Execution is suspended until [ENTER] is pressed.
The molbox1 RS232 test can fail for three reasons:
1.
The RS232 cable being used is incorrect (see Section 4.2.1.1 for
information on the correct cable).
2.
COM1 and COM2 do NOT have the same serial communications settings
and therefore cannot communicate together (see Section 3.6.6.1 to set
the COM ports).
3. COM1 or COM2 is defective.
The reason for failed communications is almost always a cable or incorrect
RS232 interface settings. Be sure that these are correct before concluding
that a COM port is defective.
3.6.7
<7DRIVERS>
 PURPOSE
To control the output signals of molbox1's 8 channel, 12 V external drivers.
The <3drivers> function is an optional feature of molbox1. If this option was not ordered
with the molbox1, the driver hardware has not been installed and the operation of
<3drivers> will have no effect.
 PRINCIPLE
molbox1 external drivers are available to drive peripheral equipment in a molbox1 system
(e.g., manifolding valves for selecting gas supply to the molbloc or automatically directing
flow to molbloc channel A or B). The driver electrical connections are available from a rear
panel connector (see Section 7.2 for driver specifications and pin outs).
 OPERATION
To access the driver control function, press [SPECIAL] and select <7drivers>.
External Drivers: 1
2 3 4 5 6 7 8
The display is:
Pressing the keypad numerical key driver number turns that driver ON and OFF with either a
momentary or a toggled response. An active driver is indicated by <*> immediately following
the driver number. Pressing [ENTER] while in the External Drivers menu causes a menu to
appear that allows selection of whether the driver actuation by selecting the driver number
will be <1momentary> or <2toggle>.
3.6.8
<8HEAD>
 PURPOSE
To cause a pressure fluid head correction to be added or subtracted to the pressure
measured by the molbox1 reference pressure transducers in order to predict the pressure at
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3. OPERATION
height the height of the molbloc when the molbloc is at a level other than the molbox1’s
reference level.
 PRINCIPLE
molbox1 measures absolute and differential pressure in molbloc flow elements. The molbox1
reference pressure transducers (RPTs) are calibrated with the height of the rear panel
pressure quick connectors as the pressure reference level. Sometimes, when performing a
calibration or test, the molbloc is at a different height than the molbox1’s pressure reference
level. This difference in height, frequently called head, can cause a significant difference
between the pressure measured by the molbox1 at its reference level and the pressure
actually present at the molbloc at a different height. In this case, it is useful to make a head
correction to the pressure measured by the molbox1 in order to predict the pressure actually
applied at a different height.
molbox1 can calculate head pressures for all the gases it supports (see Section 3.4.2),
over its working pressure range. The HEAD function allows the difference in height between
the molbox1 and the molbloc to be specified and causes the resulting head pressure to be
added to the pressure measured at the molbox1 rear panel quick connectors.
[SPECIAL], <8head>, is used to specify the height difference between the molbox1 rear
panel quick connectors and another height. Entering a height of zero turns the function off.
Use of the HEAD function to assure in tolerance measurements is most important when
using molbloc-S at high pressures. Specifying the head height within ± 3 in. (7.5 cm) is
adequate to assure that, even in the worst case, the uncertainty on the head correction
will be insignificant relative to the tolerance of the measurement.
 OPERATION
To access the HEAD function, press the [SPECIAL], <8head>. The display is:
1.
Entry field for head height.
2.
Current molbox1 gas selection.
Edit head height:
+ 25
cm
N2
Edit the head height to the desired value. Press [ENT] to return to the run screen with the
new head correction active. Press [ESC] to return with no changes.
The reference height of the molbox1
pressure measurement is the middle of the
molbox1 rear panel pressure quick
connectors. The head height should be
entered as a positive value if the molbloc is
higher than the molbox1 and negative if it
is lower.
The HEAD function is NOT channel specific. The HEAD height setting and ON or OFF
status remains the same as molbloc channels are changed.
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When a head correction is being applied, it is indicated by <h> to the right of the pressure
unit in the [P&T] screen (see Section 3.4.5). When the head correction is zero, the <h> is
not shown.
The head function is automatically disabled when running AutoZ (see Section 3.4.4.4.2)
and in the calibration run screen (see Section 5.2.4.1).
3.6.9
<9BPR>
 PURPOSE
In molbloc-S operation, to select the molbox1 BPR (back pressure ratio) measurement mode.
 PRINCIPLE
When molbloc-S elements are used with molbox1 the RPT which is normally used to read
molbloc downstream pressure, may be pneumatically connected to either the molbloc-S
nozzle’s upstream or downstream pressure, by molbox1 internal valving. The two RPTs are
used simultaneously upstream when possible to minimize the uncertainty on molbloc-S
upstream pressure measurement by averaging the two RPT readings. The upstream absolute
pressure is the most critical measurement for calculation of the flow through molbloc-S.
Measurement of molbloc-S downstream pressure is only necessary to monitor the BPR
(molbloc back pressure ratio). The value of BPR indicates whether the flow through the
molbloc-S has achieved the necessary critical flow condition (see Section 3.1.5).
When the molbox1 internal valves are positioned to connect one RPT upstream and the
other downstream of the nozzle to determine BPR, the valve state is referred to as BPR ON
(see Figure 11).
1.
Channel A High Isolation: Open
2.
Channel A Low Isolation: Open
3.
Channel B High Isolation: Closed
4.
Channel B Low Isolation: Closed
5.
Bypass: Closed
Figure 11. molbox1
Internal Pneumatic Schematic –
molbloc-S OPERATION, CHANNEL A, BPR ON
© 1995 - 2007 DH Instruments, a Fluke Company
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3. OPERATION
When the molbox1 internal valves are positioned to allow both RPTs to measure the
molbloc-S upstream pressure, the valve state is referred to as BPR OFF (see Figure 12).
1.
Channel A High Isolation: Open
2.
Channel A Low Isolation: Closed
3.
Channel B High Isolation: Closed
4.
Channel B Low Isolation: Closed
5.
Bypass: Open
Figure 12. molbox1
Internal Pneumatic Schematic –
molbloc-S OPERATION, CHANNEL A, BPR OFF
Ideally, the user is able to monitor the BPR with BPR ON while setting flows and pressures,
and once the flow is established, uncertainties can be minimized by turning BPR OFF gaining
the benefit of using both RPTs upstream. As an alternate to operator switching between BPR
ON and BPR OFF, molbox1 has a BPR mode called Auto that uses on-board logic to
determine when to turn BPR ON and OFF. In BPR Auto mode, the molbox uses cues based
on flow and pressure changes, stability, and proximity to the Reynolds number-based BPR
limits to determine when to switch between the BPR ON and BPR OFF valve states (see
Section 3.6.9). Auto is the default BPR mode and is considered the normal mode for manual
molbloc-S/molbox1 use.
For users who prefer to avoid automatic valving, there are two other BPR modes. BPR OFF
mode keeps the molbox in the BPR OFF valve state at all times. BPR ON keeps the molbox
in the BPR ON valve state at all times. BPR OFF mode should be used with caution, as it
provides no monitoring of BPR to ensure that molbloc-S measurements are valid.
When molbox1 is used in BPR OFF mode, molbox cannot measure the molbloc-S
downstream pressure and provides no monitoring or indication of the BPR. molbox1
cannot warn the user when the flow through molbloc-S is not critical and flow
measurements are not valid. For example, when the molbloc is at rest in BPR OFF mode,
and atmospheric pressure is applied to both the upstream and downstream side of
molbloc-S, the molbox1 will indicate a false flow rate approximately equal to the molbloc-S
KF value times the value of atmospheric pressure in kPa. If BPR OFF mode is used, the
user must make sure that a sufficiently low BPR is maintained while making molbloc-S
flow measurements (see Section 3.1.5). The [TARE], <5BPR> function can be used for
quick BPR checks (see Section 3.4.4.5).
 OPERATION
To access the BPR mode menu, press [SPECIAL], <9BPR>.
BPR mode:
1BPRoff 2BPRon 3Auto
The display is:
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Making a BPR mode selection, actives the selected BPR mode and returns to the previous
RUN screen. [ESCAPE] returns to the previous RUN screen without changing the BPR mode.
Selecting <1BPRoff> causes, the molbox1 internal valves to immediately switch to the BPR
OFF valve state (see Figure 12), and remain there until the user changes the BPR mode or
activates a function which causes a valve change (such as the [TARE], <5BPR> function, see
Section 3.4.4.5). In BPR OFF mode, the flow is calculated from the average of the two RPT
pressure readings and the RPT pressures displayed in the P&T pressure screen are adjusted
using the dynamic tare feature, so both pressures are displayed equal to the average value
(see Section 3.1.2 and 3.4.5)
Selecting <2BPRon> causes, the molbox1 internal valves to immediately switch to the BPR
ON valve state (see Figure 11), and remain there until the user changes the BPR mode or
activates a function which causes a valve change. In BPR ON mode, flow is calculated from
the upstream RPT measurement only. In BPR ON mode, there is no tare applied to the RPT
readings at any time.
Selecting <3Auto> does not necessarily immediately change the BPR mode.. Depending on
the current BPR mode, BPR mode changes occur as follows:
In Auto mode, in the BPR ON valve state:
molbox1 monitors the BPR value directly. If the BPR is safely below the BPR limit (calculated
from empirical testing of molbloc-S choking ratios, see Section 3.1.5), then, once the flow is
stable within 0.5 % of reading for 3 seconds, molbox1 switches to BPR OFF valve state and
begins live averaging of the RPT pressure values.
In Auto mode, in the BPR OFF valve state:
molbox1 cannot monitor BPR, but based on the proximity of the most recently measured BPR
to the calculated BPR limit, if the current flow value changes enough that it is likely that the
BPR is approaching the limit, molbox1 switches to BPR ON valve state to check BPR directly.
It is highly unlikely that valve switching will occur during critical flow measurements because,
typically, high precision flow measurements are not made when flow is changing.
In Auto mode, when the valves are in BPR OFF state, flow is calculated from the average of
the two RPT pressure readings as in BPR OFF mode. When the molbox1 valves switch to
the BPR ON valve state in Auto mode, the tare can no longer be dynamically calculated
because the two RPTs are not measuring the same pressure. The most recent tare that was
automatically calculated during the BPR OFF valve state is used to correct the pressures
used and displayed in Auto mode until the valves return to the BPR OFF state again. This assures
that flow measurements remain as consistent as possible during Auto mode valve switching
and that the tare value that is most likely to be correct is used at all times.
It is possible to change the BPR mode by remote communication with molbox1 and also to
disable molbox1 valve control and switching while in any BPR mode (see Section 4.3.4.2).
It is not possible to operate A_B modes when the active BPR mode is Auto due to
internal valving conflicts. molbox1 denies access to the A_B modes if the current BPR
mode is Auto and does not allow the user to select Auto mode when an A_B mode is
active (see Section 3.5.4).
© 1995 - 2007 DH Instruments, a Fluke Company
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4. REMOTE OPERATION
4.
REMOTE OPERATION
4.1
OVERVIEW
Most of the molbox1’s front panel functions can also be executed by commands from a remote computer.
The host computer can communicate with the molbox1 using the molbox1 COM1 RS232 port or the
IEEE-488 port. The command syntax is the same for either port except when using the IEEE STD. 488.2
Common commands.
4.2
INTERFACING
Sending a command to the molbox1 will places into remote mode. The remote indicator in the lower right
hand corner of the molbox1 front panel is illuminated when molbox1 is in remote mode. The indictor also
flickers when remote communication is occurring. The menus usually accessed from the front panel are
locked-out while in remote mode. The [P&T] key still responds to allow the user to change the data being
viewed molbox1. Pressing the [ESCAPE] key returns the molbox1 to local operation unless the
“REMOTE” command was sent to the unit. The “REMOTE” command locks out keypad operation until
the “LOCAL” command is sent.
Most remote commands will return a reply within 500 ms. You must wait for this reply before issuing
another command to the molbox1. This ensures that the molbox1 has completed the command.
An exception to this is the use of any of the IEEE STD. 488.2 Common Commands (see Section 4.3.4.1)
via the IEEE-488 interface (common commands all start with an asterisk, “*”). The common commands
only generate a reply if using the COM1 port or if the query form of the common command is used
(command followed by a “?”).
The following commands take more than 500 ms to reply:
ALLR, DP, FR, PR, RATE, SR, TARE
GAS
TARESET, DEVICE=EXT, RESET
Up to 2 seconds to allow a new measurement.
Up to 5 seconds to complete a change.
Up to 10 seconds to complete.
LabVIEW drivers are available for the molbox1. These drivers allow users of the National Instruments’
LabVIEW environment to create systems that include one or more molbox1s using LabVIEW virtual
instruments instead of using the remote commands directly. The molbox1 LabVIEW drivers are an
abstraction of the remote commands into a consistent set of common and specific
instrument functions. The drivers can be obtained at NO charge from the DHI worldwide web site,
www.dhinstruments.com.
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MOLBOX1™ OPERATION AND MAINTENANCE MANUAL
4.2.1
RS232 INTERFACE
To establish RS232 communications a standard pin to pin DB-9F to DB-9M RS232 cable
must be used to connect the host COM port to molbox1 COM1. The interface settings of
both ports must be the same.
molbox1 supports an independent RS232 self-test to verify that the molbox1 RS232
ports are operating correctly and the interface cable being used is valid. Use this selftest to troubleshoot if you are having difficulty establishing communications with
molbox1 COM1 (see Section 3.3.6.3).
4.2.1.1
COM1
The molbox1 COM1 RS232 interface is located on the rear panel. It is a 9-pin male
DB-9F connector configured as a DCE device. Data is transmitted out of molbox1
using pin 2, and is received on pin 3. This allows a standard pin to pin DB-9M to
DB-F RS232 cable to be used to connect to a DTE host. Handshaking is NOT
required or supported.
COM1 RS232 commands must be terminated with at least a single carriage return
character, while line feed characters are ignored. All RS232 responses from the
molbox1 are terminated with a carriage return character and a line feed character.
Table 28. COM1 DB-9F Pin Designation
PIN #
FUNCTION
DESCRIPTION
2
TxD
This pin transmits serial data from the molbox1 to the host.
3
5
RxD
Grn
This pin accepts serial data from the host computer.
This pin is the common return for the TxD and RxD signals.
IBM PC/XT DB-9F
CONNECTIONS
4.2.1.2
IBM PC/XT DB-9M TO PPC3 DB9F
CONNECTION
DB-25M
DB-9F
DB-9M
DB-9F
2
3
3
2
3
2
3
2
7
5
5
5
COM2
The molbox1 COM2 RS232 interface is located on the rear panel. It is a 9-pin female
DB-9M connector configured as a DTE device. Data is transmitted out of the molbox1
using pin 3 and is received on pin 2. This allows a standard pin to pin DB-9F to
DB-9M RS232 cable to be used to connect to a DCE slave. Handshaking is NOT
required or supported.
COM2 can be used to allow the host computer to communicate with another
device (e.g., another molbox or multimeter) through the molbox1. This allows the
user to use one host COM port or IEEE-488 port to communicate with the
molbox1 and an additional RS232 device. Refer to the “#” remote command for
details (see Section 4.3.4.2, # Command).
© 1995 - 2007 DH Instruments, a Fluke Company
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4. REMOTE OPERATION
Table 29. COM2 DB-9M Pin Designation
PIN #
FUNCTION
2
RxD
This pin accepts serial data from another molbox1 or
another device.
DESCRIPTION
3
TxD
4
DTR
This pin transmits serial data from the molbox1 to another
molbox1 or another device.
Data Terminal Ready. Held at + 5 Volts.
5
Grn
This pin is the common return for the TxD and RxD signals.
IBM PC/XT DB-25F TO DB-9M
CONNECTIONS
4.2.2
IBM PC/XT DB-9F TO molbox1 DB9M
CONNECTION
DB-25F
DB-9M
DB-9F
2
3
3
DB-9M
3
3
7
2
5
2
5
2
5
IEEE-488 (GPIB)
The molbox1 IEEE-488 interface is located on the rear panel. The physical and electrical
interface conforms to IEEE Std 488.1-1987 Subset E2 and IEEE Std. 488.2-1992. You should
NOT attempt to communicate with the IEEE-488 interface while using the COM1 interface.
The IEEE-488 receive buffer is 250 bytes deep. The molbox1 will hold OFF release of the
NRFD handshake line until it can service and empty the receive buffer. This keeps the buffer
from overflowing.
IEEE-488 commands must be terminated with a single line feed character along with the
assertion of the EOI line. All IEEE-488 responses from the molbox1 are terminated with a line
feed character along with the assertion of the EOI line. Replies are held in a buffer until the
host computer gets them, so it is possible to have old replies in this buffer, while you are
expecting new replies from a just issued command.
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MOLBOX1™ OPERATION AND MAINTENANCE MANUAL
4.3
COMMANDS
4.3.1
COMMAND SYNTAX
All molbox1 commands are ASCII strings. The user must wait for the molbox1 to reply before
sending another command. An exception to this is the use of any of the IEEE STD. 488.2
Common Commands via the IEEE-488 interface (these Common Commands are shown first,
and always start with an asterisk, “*”). The common commands only generate a reply if using
the COM1 port or the query form of the common command is used (command followed by a “?”).
4.3.2
COMMAND SUMMARY
Table 30. Command Summary
SYNTAX
*CLS
*ESE(?)
*ESR?
*IDN?
*OPC(?)
*OPT?
*RST
*SRE(?)
*STB?
*TST?
#
AUTOZERO(=)
ABORT
AIRW
ALLR
BEEPER
BPR(=)
CIN
COMn(=)
COUT(=)
DATE(=)
DEVICE=
DP
DRV
ERR
FA=
FCOEF
FR
FRA
FUNIT(=)
GAS(=)
ID (=)
KFACT(=)
LEAKCK(=)
LOCAL
MEM
MFCCH(=)
MOLBLOC
OHMS
PCAL
PCALDATE(=)
PCOEF
PR
PRHI
PRLO
PUNIT(=)
PURGE(=)
RANGE
PURPOSE
Clears the status registers and all queues.
Read or set the Event Status Enable register.
Read the Event Status Register.
Identify the product and software version.
Read or set the Operation Complete register (not applicable to the molbox1).
Read the molbox1 options installed.
Reset user settings to factory defaults.
Read or set the Service Request Register.
Read the Status Byte.
Read the system self-test results.
Send a command string out of the molbox1 COM2 port.
Read or set the status of the reference pressure transducers (RPTs) “AutoZ” function
Stop an active averaging, tare, leak check or purge cycle.
Read or set the humidity ratio of the gas, AIR
Read the next measurement of molbloc flow, the molbox1 up and downstream
RPT pressure values, and molbloc temperature.
To actuate the internal buzzer for half of a second.
Read or set the back pressure ratio mode when using a sonic nozzle
Read the MFC measurement current if in ‘mA’ mode.
Read or set the configuration of the COM1 or COM2 port.
Read or set the current for an external MFC if in “mA’’ mode.
Read or set the internal clock’s date.
Loads information on molbloc connected to molbox1 into molbox1.
Read the differential pressure value being used to calculate flow.
Read or set the status of an external solenoid valve.
Read the last error message.
Start a single flow averaging cycle.
Read the coefficient to convert kg/s to the current flow units.
Read the next flow measurement.
Read the results of a completed flow averaging cycle.
Read or set the flow display unit.
Read or set the gas type being used.
Read or set the molbox1 ID.
Read or set the “K” factor.
Start a molbox1 or system leak check cycle or check if a cycle is complete.
Enable the front panel controls if in remote and go to local.
Read the memory test status.
Read or set the MFC channel and output mode (voltage or current).
Read the active molbloc header data. Does not load molbloc information.
Read the most recent measurement of the active molbloc’s two PRTs.
Read or set the user RPT calibrations.
Read or set the user RPT calibration dates.
Read the coefficient to convert Pascal to the current pressure units.
Read the next molbloc average pressure.
Read the last measured upstream pressure (tare corrected).
Read the last measured downstream pressure (tare corrected).
Read or set the pressure display unit.
Read the progress of or start the purge cycle.
Read the range of the active molbloc.
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4. REMOTE OPERATION
SYNTAX
PURPOSE
RATE
RE
RES(=)
READYCK(=)
REMOTE
RESET
SN
SR
SS(=)
STDRES(=)
TARE
TARESETUP(=)
TARESET(=)
TEMP
TIME(=)
TOTAL(=)
TUNIT(=)
UDU(=)
UL(=)
USERCAL(=)
UTEMP(=)
VALVE
VER
VLM(=)
VIN
VOUT(=)
VSENSE
VSUPPLY
VVALTEST
ZOFFSET:HI
ZOFFSET:LO
4.3.3
Read the next available rate of change of flow.
Read the current Reynolds number.
Read or set the local flow display resolution.
Read or set a flag that is cleared by a Not Ready condition.
Enable remote local lockout operation.
Reset the molbox1 settings to the default operating parameters.
Read the serial number of the molbox1.
Read the next available ready status.
Read or set the stability required for a Ready <*> condition.
Read or set the PRT measurement system auto-calibration reference resistor
values .
Read the current tare conditions and the current tare.
Prepares the unit to tare.
Tare the upstream and downstream RPTs or set tare to a given value.
Read the current molbloc temperature in the current units.
Read or set the internal clock’s time.
Read the progress of or start a new totalize cycle.
Read or set the molbloc temperature unit.
Read or set the user definable pressure unit.
Read or set the upper limit for the internal RPTs.
Read or set the user flow measurement adjustment.
Read or set the temperature reference used for the user flow units.
This command is obsolete and should not be used in new designs.
Read the molbox1 version.
Read or set the volume units pressure & temperature conditions.
Read the MFC measurement voltage if in voltage mode.
Read or set the voltage sent to an external MFC if in voltage mode.
Read the voltage sensed at the MFC terminal.
Read MFC supply voltage.
Read voltage sensed at MFC valve test terminal.
Read or set the AutoZ pressure offset, (Poffset), for the high RPT .
Read or set the AutoZ pressure offset, (Poffset), for the low RPT .
ERROR MESSAGES
molbox1 always replies to a command. If the command is incorrect or contains invalid data,
an error number is returned in the form “ERR# n” where n is an integer number that
represents a specific error. This allows for easy error trapping by the host computer.
Table 31 is a list of the possible error numbers and the error description for each.
Table 31. Error Messages
REPLY
ERROR
ERR# 0
ERR# 1
ERR# 2
ERR# 3
ERR# 4
ERR# 5
ERR# 6
ERR# 7
ERR# 8
ERR# 9
ERR# 10
ERR# 11
ERR# 12
ERR# 13
ERR# 14
ERR# 15
DESCRIPTION
"The molbox1 is in high security level and cannot accept
remote commands"
"OK"
"molbloc flow is too great"
"Text argument is too long"
"User defined coefficient cannot be 0"
"External device not detected"
"External device improperly configured"
"Numeric argument missing or out of range"
"Missing or improper command argument(s)"
"External device timeout error"
"Unknown command"
"MFC not defined or selected"
"Command missing argument"
"System overpressured"
"Text detected in numeric field"
"User unit not defined"
"Averaging cycle not started"
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ERR# 16
ERR# 17
ERR# 18
ERR# 21
ERR# 22
ERR# 23
ERR# 24
ERR# 25
ERR# 26
ERR# 27
ERR# 28
ERR# 29
ERR# 30
ERR# 31
ERR# 32
ERR# 34
ERR# 35
ERR# 36
ERR# 37
ERR# 38
ERR# 39
ERR# 40
ERR# 41
ERR# 42
ERR# 43
ERR# 44
ERR# 45
ERR# 46
ERR# 47
ERR# 48
ERR# 49
ERR# 50
ERR# 51
ERR# 52
ERR# 53
ERR# 54
ERR# 55
4.3.4
"MFC Malfunction"
"Selected gas not available"
"Command not yet available"
"User device not defined"
"Pressure is not stable"
"Option not available or installed"
"molbloc not detected"
"RPT out of calibration"
"COM port failed to initialize"
"Internal device #1 timeout error"
"Internal device #2 timeout error"
"Busy averaging"
"Fatal mass flow calculation error"
"molbloc EEPROM is full"
"molbloc gas not found"
"molbloc is write protected"
"molbloc write error"
"MFC unit mismatch"
"Incompatible device detected""
"Selected range not available"
"molbloc verify error"
"molbloc read error"
"molbloc invalid"
"PRT measurement error"
"Incorrect MFC mode"
"Entry already exists"
"Argument(s) not allowed"
"The leak is too large"
"Temperature change was too great"
"Offset was excessive. Check tare"
"Possible upstream leak"
"Possible downstream leak"
"Possible bypass leak"
"Not available in AB mode"
"Suffix not allowed"
"Suffix missing or out of range"
"Not Ready"
COMMAND DESCRIPTIONS
Each command description gives the full syntax showing usage. Ranges of parameters or
parameter types are indicated. There are 2 types of commands. The Common and Status
Commands support IEEE Std. 488.2, while the molbox1 commands access all other functions.
4.3.4.1
IEEE STD. 488.2 COMMON AND STATUS COMMANDS
The molbox1 supports a set of commands that are common to all instruments
conforming to IEEE Std. 488.2 protocol. Though defined by the IEEE-488.2 standard,
they also apply to molbox1 RS232 (COM1) communications. These commands
make it easy to perform basic functions for any device that supports them.
These command also cover the status reporting commands. Refer to Section 4.4
for details on the status registers mentioned in these commands. Query forms of
these commands must be followed by a question mark and IEEE-488.2 Common
Commands always start with an asterisk (“*”). Unlike the other molbox1 commands,
they must have a space instead of an equals sign (“=”) between the command
and any arguments. Also unlike the other molbox1 commands, if you are using
© 1995 - 2007 DH Instruments, a Fluke Company
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4. REMOTE OPERATION
the IEEE-488 port, the query form (command is immediately followed by a “?”)
must be used to get a reply. If using the COM1 port and the command is not a
query, “OK” will be replied.
∗CLS
Purpose
Syntax
Remarks
Example
∗ESE(?)
Purpose
Syntax
Parameters
Query Reply
Remarks
Example
∗ESR?
Purpose
Syntax
Query Reply
Remark
Example
∗IDN?
Purpose
Syntax
Remarks
Query Reply
Example
∗OPC(?)
Purpose
Syntax
Remarks
Query Reply
Example
Clear all of the status and event structures.
“∗CLS”
This program message clears the following evens and status registers:
Standard Byte Register (STB)
Standard Event Status Register (ESR)
Error Queue
Pending OPC operations
Command:
“*CLS”
Reply:
“OK” (using COM1. No reply if IEEE-488 port)
Read or set the Standard Event Status Enable Register.
“∗ESE n”
“∗ESE?”
’0 to 255’. This is the decimal representation of the bit(s) to
n:
enable. To enable the PON and QYE bits, the argument would
be 128 + 4 = 132.
n (0 to 255)
The Standard Event Status Enable register determines which bits in the standard
Event Status Register are enabled and included in the Status Byte Register (ESB
bit), and can assert the SRQ line. The reply is in decimal numeric form.
Command:
“*ESE 132”
Reply:
“OK” (using COM1. No reply if IEEE-488 port)
Command:
“*ESE?”
Reply:
“132”
Read the Standard Event Register.
“∗ESR?”
n (0 to 255)
The Standard Event Register contents are cleared after reading. The reply is in
decimal numeric form.
Command:
“*ESR?”
Reply:
“4”
Identify the molbox1 version, range, and serial number.
“∗IDN?”
The identification reply is made up of the manufacturer, the model, the serial
number, the internal RPT serial numbers and the software version. Each is
separated by a comma.
The version string.
Command:
“*IDN?”
Reply:
“DH INSTRUMENTS INC, molbox1, 620-84836-85056,
Ver5.20X-lflfka”
Sets the operation complete bit when all operations have completed.
“∗OPC”
“∗OPC?”
This command enables the molbox1 to set the OPC bit in the Standard Event
Status Register when it has completed all pending functions. The Query replies
with a “1” when all functions are complete.
Since the molbox1 does not support overlapping commands, this command has
no practical use.
“0” or “1”
Command:
“*OPC”
Reply:
“OK” (using COM1. No reply if IEEE-488 port)
Command:
“*OPC?”
Reply:
“1”
Page 115
© 1995 - 2007 DH Instruments, a Fluke Company
MOLBOX1™ OPERATION AND MAINTENANCE MANUAL
∗OPT?
Purpose
Syntax
Remarks
Query Reply
Example
∗RST
Purpose
Syntax
Remarks
Example
∗SRE(?)
Purpose
Syntax
Parameters
Remarks
Query Reply
Example
∗STB?
Purpose
Syntax
Remarks
Query Reply
Example
∗TST?
Purpose
Syntax
Remarks
Query Reply
Example
© 1995 - 2007 DH Instruments, a Fluke Company
Reads the list of installed molblox1 options.
“∗OPT?”
This Query returns any registered option(s) installed in the molbox1. Each option
is separated by a comma.
A comma delimited text field of the installed options.
Command:
“*OPT?”
Reply:
“NONE” (no options installed)
Resets the molbox1 settings to factory settings.
“∗RST”
This command sets the molbox1 settings to factory settings which is equivalent to
pressing [SPECIAL] on the front panel and selecting <5Reset>, 1sets. This does
not affect the communications settings.
Command:
“*RST”
Reply:
“OK” (using COM1. No reply if IEEE-488 port)
Read or set the Service Request Enable Register.
“∗SRE n”
“∗SRE?”
‘0 to 255’. This is the decimal representation of the bit(s) to
n:
enable. To allow the MAV and ESB bits to assert the SRQ line,
the argument would be 32 + 16 = 48. Bit 6 (64) is reserved and
cannot be set.
The Service Request Enable Register determines which bits of the Status Byte
can set the MSS bit of the Status Byte and request service by asserting the SRQ
line of the IEEE-488 interface.
n (0 to 255)
Command:
“*SRE 48”
Reply:
“OK” using COM1. No reply if IEEE-488 port)
Command:
“*SRE?”
Reply:
“48”
Read the Status Byte Register.
“∗STB?”
The Status Byte Register reflects the general status of the molbox1. The ‘MSS’
bit state is represented by bit 6.
n (0 to 255)
Command:
“*STB?”
Reply:
“4”
Read the power on self test status.
“∗TST?””
The molbox1 system memory stores the user settings (units, mode, resolution)
and retains them when the unit is shutoff. On power up, this memory is checked.
If this memory is corrupted, all user settings are reset to default (as if the “∗RST”
program message was executed), and the ∗TST query returns a ‘1’. If the
molbox1 passed the test on power up OR if the ∗TST query was used at least
once since the unit was powered up the reply is ‘0’.
“0” or “1”
Command:
“*TST?”
Reply:
“1”
Page 116
4. REMOTE OPERATION
4.3.4.2
#
Purpose
Syntax
Arguments
Remarks
Example
ABORT
Purpose
Syntax
Remarks
Example
See Also
AIRW(=)
Purpose
Syntax
Default
Arguments
Remarks
Example
Errors
See Also
molbox1 COMMANDS
To allow the Host computer to communicate with a device connected to the
molbox1 COM2 port.
“#XX”
xx:
The string to send out of the COM2 port. It must be less than
40 characters long.
The molbox1 COM2 port can be used to communicate to another RS232 device
(e.g., another molbox1 or a multimeter). This allows the user to use one COM
port or IEEE-488 port on the host computer to communicate with the molbox1 and
another device. A carriage return and a line feed (<CR><LF>) are added to the
string.
After this command is issued, the molbox1 will reply back the first string received
by the molbox1 COM2 port that is terminated with a carriage return. Line feeds
are discarded. This will discontinue when the next command is sent to the
molbox1.
There is no other reply from this command. Prior to using this command, you
must ensure that the molbox1 COM2 port is correctly set up to communicate with
the device. Refer to the “COM2=“ command.
Command:
“#VER”
Reply:
“DH INSTRUMENTS, INC molbox1 Ver1.01”
To stop an active averaging, tare, purge or leak check cycle.
“ABORT”
This command should be used to ensure that molbox1 in a known state. The
tare, purge, and leak check cycles put the molbox1 into a condition where it is not
usable for normal flow measurement, so the “ABORT” command should be used
before general operation of the unit begins if the previous state of the unit is not
known. The “ABORT” command also clears out any previous leak or tare cycle
errors.
Command:
“ABORT”
Reply:
“ABORT”
“FA”, “TARESETUP”, “LEAKCK”, “PURGE”
Read or set the humidity ratio for the gas, AIR.
“AIRW=HumidityRatio”
“AIRW”
“AIRW=0.00
00”
The humidity ratio (0-0.1)
HumidityRati
o:
The humidity ratio is only used if the gas is set to specify AIR. For all other gas
types, the ratio is ignored.
Command:
“AIRW=.01”
Reply:
“0.0100”
ERR# 6:
The humidity ratio is invalid.
3.2.2, 3.4.2.2
“GAS”
Page 117
© 1995 - 2007 DH Instruments, a Fluke Company
MOLBOX1™ OPERATION AND MAINTENANCE MANUAL
ALLR
Purpose
Syntax
Remarks
Example
Errors
See Also
AUTOZERO(=)
Purpose
Command
Query
Default
Arguments
Remarks
Example
Errors
See Also
BEEPER(=)
Purpose
Syntax
Arguments
Remarks
Example
© 1995 - 2007 DH Instruments, a Fluke Company
Read the next ready/not ready indication, measurement of molbloc flow, the
molbox1 upstream and downstream RPT pressure values and the molbloc
temperature.
“ALLR”
The next available measurements are replied. This can take up to 1 second,
since the molbox1 waits for the next flow measurement before replying. The reply
starts with the flow ready information. Then the flow value is given in the current
flow units. Commas are then used to separate the other measurements in this
order:
“RDY flow, avgpres, uppres, dnpres, temp”.
“RDY” is the flow ready field. The ready status is covered in the “SR” command.
“flow” is the current measured flow and flow units. “-999999” in this field when
using a molbloc-S indicates that the BPR is too low for a correct flow
measurement.
“avgpres” is the average of the upstream and downstream RPTs and units.
“uppres” is the upstream RPT pressure measurement and units.
“dnpres” is the downstream RPT pressure measurement and units.
“temp” is the molbloc temperature and units.
“ALLR”
Command:
“R
0.00075 slm,97.3844 kPa,97.3945 kPa,97.3743 kPa,
Reply:
17.97C”
“NRP -999999 slm,97.3844 kPa,97.3945 kPa,97.3743 kPa,
Reply:
17.97C” (BPR too low)
ERR# 27 or One of the RPTs (pressure transducers) is not functioning.
28:
3.1.2.2, “SR”, “READYCK”, “DP”, “PRHI”, “PRLO”, “FR”
Read or set the status of the reference pressure transducer (RPT) AutoZ function.
“AUTOZERO=n”
“AUTOZERO”
“AUTOZERO=1”
n:
’0’ Autozero OFF
’1’ Autozero ON
The molbox “AutoZ” function can be turned ON and OFF. This command sets the
AutoZ status for both of the internal RPTs.
Sent:
“AUTOZERO=1”
Query reply:
“AUTOZERO=1”
ERR# 6:
The argument was other than a ‘0’ or a ‘1’.
3.4.4.4, “ZOFFSET:XX”
To actuate the internal buzzer for half of a second.
“BEEPER”
“BEEPER=freq”
freq:
This variable has no purpose, but is included for compatibility
with the DH Instruments RFM product.
The internal buzzer tone is fixed, so the argument serves no purpose.
Command:
“BEEPER=1000”
Reply:
“1000”
Page 118
4. REMOTE OPERATION
BPR(=)
Purpose
Command:
Query:
Defaults
Arguments
Remarks
Example
Errors
See Also
CIN
Purpose
Syntax
Remarks
Example
See Also
COMn(=)
Purpose
Syntax
Arguments
Defaults
Remarks
Example
Error
See Also
Read or set the back pressure ratio (BPR) mode. This is only available when
using a molbloc-S.
“BPR =mode”
“BPR=mode, suspend
“BPR”
“BPR=2,0”
‘0’ BPR is kept “OFF”
mode:
‘1’ BPR is kept “ON”
‘2’ BPR is in “auto” mode.
‘0’ BPR normal operation
suspend:
‘1’ BPR function is suspended, left in the current condition until
set back to normal operation.
The BPR mode determines the operation when the back pressure ratio is
measured when using molbloc-Sto measure flow. The optional “suspend”
argument can be used to leave the BPR valve state in its current condition,
allowing manual manipulation of the molbox valves without the BPR function
intervening. If the “suspend” argument is not given, it is presumed to be ‘0’ for
normal BPR operation.
“BPR=2”
Sent:
“2, 0”
Reply:
“BPR=1,1”
Sent:
“1, 1”
Reply:
ERR# 6:
One of the arguments is out of range.
3.6.9
Read the MFC measurement current if in ‘mA’ mode.
“CIN”
The optional MFC interface can measure current output of an MFC. The molbox1
must be in ‘mA’ mode before this can be done (see the “MFCCH” command).
The returned data is always in “mA”.
Command:
“CIN”
Reply:
“5.34 mA”
3.2.8
To set or read the configuration of the COM1 or COM2 ports.
“COMn=baud,parity,data,stop”
“COMn”
n:
The COM port: ‘1’ or ‘2’.
Baud:
The baud rate. This may be ‘300’, ‘600’, ‘1200’, ‘2400’, ‘4800’,
‘9600’ or ‘19200’.
parity:
The data parity. This may be ‘O’ for odd, ‘E’ for even or ‘N’ for
none.
data:
The data word length. This may be ‘7’ or ‘8’.
stop:
The number of stop bits. This may be ‘1’ or ‘2’.
“COM1=2400,E,7,1”
“COM2=2400,E,7,1”
The COM1 port is used to communicate to the molbox1. When the COM1 port
configuration of the molbox1 is changed, the command reply will be sent at the
old COM1 settings, but all subsequent communications will be accomplished at
the new COM1 settings.
The COM2 port is used to allow commands to be passed through the molbox1 to
a device connected to the COM2 port (refer to the ‘#’ command).
Command:
“COM1=9600,N,8,1”
Reply:
“9600,N,8,1”
ERR# 7:
Missing or improper command argument(s).
3.6.6.1
Page 119
© 1995 - 2007 DH Instruments, a Fluke Company
MOLBOX1™ OPERATION AND MAINTENANCE MANUAL
DATE(=)
Purpose
Syntax
Arguments
Example
Errors
See Also
COUT(=)
Purpose
Syntax
Arguments
Defaults
Remarks
Example
See Also
DEVICE(=)
Purpose
Syntax
Arguments
Defaults
Remarks
Example
Errors
See Also
DP
Purpose
Syntax
Remarks
Example
See Also
© 1995 - 2007 DH Instruments, a Fluke Company
Read or set the internal clock date.
“DATE”
“DATE=yyyymmdd
The year from 1980 to 2079.
yyyy:
The month from 1 to 12.
mm:
The day from 1 to the last valid day of the given month.
dd:
Command:
“DATE=19981005”
Reply:
“19981005”
ERR# 6:
The time date is invalid.
3.6.5.3
Set a current to the MFC if in current mode.
“COUT=current”
Current:
The current to be sent to the MFC (4 to 20 mA).
“COUT=4”
The optional MFC interface can set a current for an MFC. The molbox1 must be
in current mode before this can be done (see the “MFCCH” command). The data
is always in “mA”. This command does not change the regulation mode target for
the MFC.
Command:
“COUT=12”
Reply:
“12.00 mA”
3.4.8
Select to use the ‘A’, ‘B’ or both the ‘A’ and ‘B’ molblocs.
“DEVICE=n”
“DEVICE”
Device:
‘A’ to select molbloc A.
‘B’ to select molbloc B.
‘A+B’ to select molbloc A and B in A+B mode.
‘EXT’ to reload molbloc A and molbloc B data.
“DEVICE=A”
The molbloc calibration data is stored in the external molbloc. This data is
normally loaded on power up, but can be reloaded using this command if the
molbloc has been changed since power up. Loading the data normally takes less
than a second, but can take up to 10 seconds if the molbox has problems
communicating with the molbloc. When using molbloc-S, A+B mode cannot be
selected if “BPR” mode is set to “auto”
Command:
“DEVICE=B”
Reply:
“B”
ERR# 6:
BPR is in auto mode and “A+B” mode was requested
ERR# 7:
Text argument in invalid
ERR# 24:
A molbloc is not connected to the molbox1.
ERR# 35:
The molbloc experienced a communications timeout.
ERR# 40:
The molbloc experienced a read checksum failure.
ERR# 41:
The molbloc data header is corrupted.
3.1.1
Read the differential pressure value used by molbox1 to calculate flow.
“DP”
The molbox1 has upstream and downstream absolute RPTs. The pressure
returned by this command is the differential pressure value that is being used by
molbox1 to calculate flow. This is the tare adjusted difference between the 2
absolute RPTs. The first 3 characters of the reply from molbox1 make up the
Ready/Not Ready condition (see the “SR” command). The differential pressure
string follows it.
Command:
“DP”
Reply:
“R
0.0227 kPa”
“SR”
Page 120
4. REMOTE OPERATION
DRVn(=)
Purpose
Syntax
Arguments
Defaults
Remarks
Example
Errors
See Also
ERR
Purpose
Syntax
Remarks
Example
See Also
FA=
Purpose
Syntax
Arguments
Remarks
Example
Errors
See Also
FCOEF
Purpose
Syntax
Remarks
Example
See Also
FR
Purpose
Syntax
Remarks
Example
Errors
See Also
Read or set the status of an external solenoid valve.
“DRVn=x”
“DRVn”
N
The valve to operate on. This can be from 1 to 8.
X
The state to change the valve to. ‘0’ to de-activate it. ‘1’ to
activate it.
“DRVn=0”
The molbox1 has the option of controlling up to eight external valves.
Command:
“DRV3”
Reply:
“DRV3=1”
ERR# 6:
The n or x arguments are not within given limits.
3.6.7, 7.2
Read the last error message.
“ERR”
The “ERR” command provides more details about an error that has occurred. If
the user receives an “ERR# nn” reply, the “ERR” command returns a brief
description about the last error number that was replied.
Command:
“ERR”
Reply:
“Missing or improper command argument(s)”
4.3.3, “*CLS”
Start a single flow averaging cycle.
“FA=period”
period:
The averaging period in seconds
(from 20 to 999 seconds if A+B mode, otherwise 4-999 seconds).
This command is used to start an averaging period that results in the average
molbloc flow, MFC measurement, and standard deviation of the molbloc flow over
this period. After sending this command you can monitor the averaging cycle by
using the “FR” or “SR” command to determine when the averaging cycle is
complete. Once the cycle is done, you must use the “FRA” command to collect
the results.
Command:
“FA=20”
Reply:
“20 s”
ERR# 6:
The period argument is not within the specified limits.
3.4.6.2 , “FR”, “SR”, “FRA”, “ABORT”
Read the coefficient that converts kg/s to the current flow units.
“FCOEF”
The flow coefficient is a value that is used to convert kg/s to the current flow units.
It is dependent on the current flow unit and the gas selected. To use this
coefficient, multiply it by kg/s to get flow in the current flow units.
Command:
“FCOEF”
Reply:
“4.798073e+004”
3.4.3, 7.1.3
Read the next measurement of flow through the molbloc as calculated by the
molbox1.
“FR”
The next available flow value is read in the current flow units. This can take up to
1 second, since the molbox1 waits for the next flow measurement before replying.
The reply also contains ready information.
The first 3 characters are reserved for the ReadyNot Ready status. The
Ready/Not Ready status is covered in the “SR” command.
The flow
measurement number starts at the fifth character, and is followed by the flow
units.
Command:
“FR”
Reply:
“R
0.00001 sccm”
ERR# 27:
One of the RPTs (transducer) is not functioning.
“BUSY”
The molbox is busy calculating an A+B flow value.
3.1.3 , “SR”, “READYCK”
Page 121
© 1995 - 2007 DH Instruments, a Fluke Company
MOLBOX1™ OPERATION AND MAINTENANCE MANUAL
FRA
Purpose
Syntax
Remarks
Example
Errors
See Also
FUNIT(=)
Purpose
Syntax
Defaults
Arguments
Remarks
Example
Errors
See Also
GAS(=)
Purpose
Syntax
Arguments
Remarks
Example
Errors
See Also
© 1995 - 2007 DH Instruments, a Fluke Company
Read the results of a completed flow averaging cycle.
“FRA”
This command is used to check on the status of or collect the results of an
averaging cycle that was started earlier using the "FA=" command. During the
averaging cycle, this command will reply "BUSY" until the averaging cycle is
complete. Then the reply will be the results of the averaging cycle. If the cycle is
aborted before it is complete (see "FA="), then the data will be lost.
The data that is returned from the command consists of multiple numeric fields
delimited by commas. The flow numbers are in the current flow unit of measure.
The actual data fields returned are as follows:
An "H" will appear as the first character of the reply string. An "S" will appear as
the second character of the string if the flow stability stayed within the stability setting
during the sequence. From the fourth position on the numeric data fields are:
Average flow over the averaging period.
Standard deviation of flow over the averaging period.
The minimum flow reached during the period.
The maximum flow reached during the period.
“NA” always.
“NA” always.
If a molbloc-S is active and the BPR becomes too large for a flow to be calculated
during the average cycle, the cycle is aborted and “-999999” will appears in all
flow related fields in the reply.
“FRA”
Command:
“HS 0.00002 sccm,0.00000,0.00002,0.00002,NA, NA”
Reply:
“BUSY” if still averaging
Reply:
“HS -999999 sccm,-999999,-999999,-999999,NA, NA”
Reply:
(BPR became too hight during the average cycle)
ERR# 15:
The “FA=” command was not sent previous to this command.
3.4.6.2 , “FR”, “SR”, “FA”
Read or set the unit of measurement for the flow through the molbloc as
calculated by the molbox1.
“FUNIT=unit”
“FUNIT”
“FUNIT=sccm”
unit:
The flow unit used to display the measured flow.
The flow unit displayed can be changed using this command. The flow unit must
be supported by the molbox1. The flow unit protocol is the same as the front
panel flow unit definitions.
Command:
“FUNIT=SLM”
Reply:
“SLM”
ERR# 7:
The flow unit is invalid or not supported by the molbox1.
3.4.3, “UTEMP”, “VLM”
Read or set the gas type being flowed through the molbloc.
“GAS=gas
“GAS”
The gas to use.
gas:
The gas type being flowed through the molbloc is specified using this command.
The gas must be supported by the molbox1. The gas type protocol is the same
as the front panel gas definitions. A valid molbloc must be connected to the
molbox1 before changing the gas type.
Command:
“GAS=N2”
Reply:
“N2”
The gas is invalid for the molbox1.
ERR# 7:
A molbloc is not connected to the molbox1.
ERR# 24:
This gas is not supported by the molbox1.
ERR# 32:
The molbloc experienced a communications time out.
ERR# 35:
The molbloc experienced a data verification failure.
ERR# 39:
The molbloc experienced a read checksum failure.
ERR# 40:
The molbloc data header is corrupted.
ERR# 41:
3.4.2, “AIRW”
Page 122
4. REMOTE OPERATION
ID(=)
Purpose
Syntax
Default
Arguments
Remarks
Example
See Also
KFACT(=)
Purpose
Syntax
Arguments
Defaults
Remarks
Example
See Also
LEAKCK(=)
Purpose
Syntax
Arguments
Remarks
Example
Y
See Also
Read or set the user defined identification label.
“ID=string”
“ID”
“ID=NONE”
String:
An alphanumeric string up to 12 characters wide.
The user defined ID label can be used to allow the user to “tag” the molbox1 with
a unique identifier. This ID is stored in non-volatile memory and cannot be erased
by a power failure, system fault or reset.
Command:
“ID=molbox-001”
Reply:
“molbox-001 ”
3.6.5.2
Read or set the molbox1 K factor.
“KFACT=kfactor”
“KFACT”
Kfactor:
The new “K” factor.
“FACT=1.0” (Disabled)
The “K” factor is set to 1 for normal operation.
Command:
“KFACT”
Reply:
“1.000000”
3.4.1
Starts a molbox1 or system leak check cycle or checks if a cycle is complete.
“LEAKCK=type”
“LEAKCK”
type:
“BOX”. Starts a leak check cycle on the molbox1 internal circuit.
The molbox must be prepared for the leak check by setting
pressures and venting ports before the leak check is executed.
“SYS”. Starts a leak check cycle on the system connected to the
molbox1. The system must be prepared for the leak check by setting
pressures and operating valves before the leak check is executed.
This command is used to start and monitor the progress of the leak check. Both
“BOX” and the “SYS” leak checks take 60 seconds to complete. At the end of the
leak check, the molbox1 is returned to its normal operating state.
The “ABORT” command can be used to stop a leak check cycle, clear out any
previous error messages, and return the molbox1 to its normal operating state.
While the leak check cycle is executing, a ‘b’ (“busy”) will appear in the 3rd
character position of the “FR” and the “SR” command replies.
If the leak check failed, an error will be replied to the “LEAKCK” query until the
“ABORT” command is used to abort the leak check. When the leak check has
completed without an error, the “LEAKCK” query will reply “OK”.
If a molbloc-S is active and a “SYS” type leak check was run, the reply is the
actual average leak rate (in the current pressure units) during the leak check.
The “LEAKCK” command must be completed or aborted using the “ABORT”
command before performing other operations.
“LEAKCK=BOX,1”
Command:
“BOX” (starting new molbox1 leak check cycle including the
Reply:
microrange RPT)
Command:
“LEAKCK=SYS”
Reply:
“SYS” (starting new system leak check cycle)
Command:
“LEAKCK”
Reply:
“23 sec” A leak check cycle is currently running. This is the
number of seconds remaining in the test.
Reply:
“OK”
(The leak check cycle has completed)
Reply:
“0.3412 kPa/s” if a molbloc-S is active and the “SYS” type leak
check has been completed.
One of the arguments is not invalid.
ERR# 6:
A leak check cycle has not been started.
ERR# 15:
A large leak exists.
ERR# 46:
The temperature changed too much to test for a leak.
ERR# 47:
The absolute RPT disagreement too great to test for a leak.
ERR# 48:
Possible upstream leak.
ERR# 49:
Possible downstream leak.
ERR# 50:
Possible bypass leak.
ERR# 51:
3.4.4.3, “ABORT”
Page 123
© 1995 - 2007 DH Instruments, a Fluke Company
MOLBOX1™ OPERATION AND MAINTENANCE MANUAL
LOCAL
Purpose
Syntax
Remarks
Example
See Also
MEM
Purpose
Syntax
Remarks
Example
MFCCH
Purpose
Syntax
Defaults
Arguments
Remarks
Example
Errors
See Also
© 1995 - 2007 DH Instruments, a Fluke Company
Enable the front panel controls if in remote and go to local mode.
“LOCAL”
In LOCAL mode, all front panel operations are available. The LOCAL command
deactivates REMOTE mode.
Command:
“LOCAL”
Reply:
“LOCAL”
“REMOTE”
Read the memory test status.
“MEM”
On power up a memory test is run to check the integrity of the internal data NVRAM.
If the memory has been corrupted, "FATAL MEMORY FAULT" will be displayed
on power up to alert the user, and the memory test status command will return a ‘0’.
The command will return a ‘1’ if the memory is OK.
Command:
“MEM”
Reply:
“0”
Read or set the MFC channel and output mode (voltage or current).
“MFCCH=channel,mode”
“MFCCH”
“MFCCH=1,v”
channel:
The optional MFC switchbox channel.
disables the MFC interface.
0
enables the optional MFC interface.
1
selects the MFC channel to use for optional MFC
1 to 5
switchbox
mode:
The MFC interface mode
‘v’
Voltage
control
and
measure
mode.
The selected channel will be used for voltage
‘mA’
setting and measuring.
Current loop control and measure mode.
The selected channel will be used for current
‘ ‘
loop setting and measuring.
If the argument is not given, the molbox will use
the selected channel to measure the voltage,
and will always use channel 1 to set the voltage.
This is used to measure voltage MFM’s that are
connected to channel 2 through 5 with an MFC
controlling on channel 1.
The optional MFC interface can support voltage or current controlled MFC’s.
There is also an available MFC switchbox, which is controlled by the molbox1.
Command:
“MFCCH=1,
Enables MFC for current
Reply:
mA”
“1,mA”
Command:
“MFCCH=3,
Enables MFC on switchbox channel 3 for volts
Reply:
V”
“1,mA”
Command:
“MFCCH=0”
Disables MFC interface
Reply:
“0,V”
Enables MFC control on channel 1
“MFCCH=1,
Command:
V”
Reply:
Enables MFM input on channel 4
“1,V”
Command:
“MFCCH=4”
Reply:
“4,V”
ERR# 6:
Channel or mode arguments are invalid
ERR# 23:
The MFC option is not installed
ERR# 23:
Channel greater than 1 and MFC switchbox option is not installed
3.4.8, 7.3
Page 124
4. REMOTE OPERATION
MOLBLOC
Purpose
Syntax
Remarks
Example
Errors
See Also
OHMS
Purpose
Syntax
Remarks
Example
See Also
PCAL(=)
Purpose
Syntax
Defaults
Arguments
Remarks
Example
Errors
See Also
Read the active molbloc header data. This command does NOT load molbloc
information.
“MOLBLOC”
The external molbloc header data includes the serial number, range, calibration
date, and PRT calibration data. This data is stored in the molbloc, and is
downloaded to the molbox1 on power up. The data for the active molbloc is
returned in a single, comma delimited string in the following order:
Serial Number
Range Designator
Range Flow Units
Gas
Calibration Date (yyyymmdd)
Total PRT Resistance (upstream + downstream) at 0 °C [Ω]
PRT Slope [dimensionless]
Upstream PRT Resistance at 0 °C [Ω]
Downstream PRT Resistance at 0 °C [Ω]
molbloc-S Serial Number if the molbloc is a “-S” or same as the molbloc serial
number if a the molbloc is a “-L” molbloc.
“S” or “L” depending on whether the molbloc is a “-S” or “-L”.
“MOLBLOC”
Command:
“100, 1.00, sccm, N2, 19980426, 200.0050, 0.7792, 100.0010,
Reply:
100.0040, 100, L”
(molbloc-L)
100, 1.00, sccm, N2, 19980426, 200.0050, 0.7792, 100.0010,
Reply:
100.0040, 120, S”
(molbloc-S)
The gas is invalid with the molbox1.
ERR# 7:
A molbloc is not connected to the molbox1.
ERR# 24:
The molbloc experienced a communications timeout.
ERR# 35:
The molbloc experienced a read checksum failure.
ERR# 40:
The molbloc data header is corrupted.
ERR# 41:
3.5.1, “DEVICE”
Read the most recent measurement of the active molbloc’s two PRTs.
“OHMS”
?????
Sent:
“OHMS”
Reply:
“109.031 Ohms, 109.037 Ohms”
5.4, 3.4.5, “TEMP”
Read or set the user RPT calibration adjustments (PA, PM).
“PCAL=upadder, upmult, dnadder, dnmult”
“PCAL”
“PCAL=0, 1.00000, 0, 1.00000”
Upadder:
The upstream RPT calibration adder (PA) from –10 000 to
10 000 Pa.
Upmult:
The upstream RPT calibration multiplier (PM) from 0.9 to 1.1.
Dnadder:
The downstream RPT calibration adder from –10 000 to
10 000 Pa.
Dnmult:
The downstream RPT calibration multiplier from 0.9 to 1.1.
Mradder:
The optional microrange RPT calibration adder from –10 000 to
10 000 Pa.
The user defined pressure calibration for the upstream and downstream RPTs
can be access with this single command. The adder is always in Pascal.
Command:
“PCAL=38, 1.0021, 14, .9942”
Reply:
“ 38.00 Paa, 1.002100, 14.00 Paa, 0.994200”
ERR# 6:
Invalid argument.
5.2
Page 125
© 1995 - 2007 DH Instruments, a Fluke Company
MOLBOX1™ OPERATION AND MAINTENANCE MANUAL
PCALDATE(=)
Purpose
Read or set the user RPT calibration dates.
Syntax
“PCALDATE=yyyymmdd, yyyymmdd”
“PCALDATE”
Defaults
“PCALDATE=19980101,19980101
Arguments
yyyy:
The year from 1980 to 2079.
mm:
The month from 1 to 12.
dd:
The day from 1 to the last valid day of the given month.
Remarks
The user defined pressure calibration dates for the upstream and downstream
RPTs can be access with this single command in this order.
Example
Command:
“PCALDATE=19981005, 19981005”
Reply:
“19981005, 19981005”
Errors
ERR# 7:
One or more of the date(s) are invalid.
See Also
5.2, “PCAL(=)”
PCOEF
Purpose
Syntax
Remarks
Example
See Also
PR
Purpose
Syntax
Remarks
Example
See Also
PRHI
Purpose
Syntax
Remarks
Example
See Also
PRLO
Purpose
Syntax
Remarks
Example
See Also
PUNIT(=)
Purpose
Syntax
Defaults
Arguments
Remarks
Example
Errors
See Also
© 1995 - 2007 DH Instruments, a Fluke Company
Read the coefficient to convert Pascal [Pa] to the current pressure units.
“PR”
The pressure coefficient (PCOEF) is a value that is used to convert Pascal units
to the current pressure units. To use this coefficient, multiply it by pressure in
Pascal to get pressure in the current units.
Command:
“PCOEF”
Reply:
“1.000000e-003”
3.5.8, 7.1.1, “PUNIT”
Read the next molbloc average pressure.
“PR”
⎛ upstream − downstream ⎞
⎟ pressure value is read in
⎝
⎠
2
The next available average ⎜
the current pressure units. It is the average of the tare corrected upstream and
the downstream transducers.
The data string also contains flow ready
information, and the pressure units.
The first 3 characters of the reply are reserved for the flow ReadyNot Ready status.
The Ready/Not Ready status is covered in the “SR” command. The pressure
measurement number starts at the fifth character, and is followed by the pressure
unit of measure.
Command:
“PR”
Reply:
“R
247.5982 kPa a”
“READYCK”, “SR”, “DP”, “PRHI”, “PRLO”
Read the last measured upstream absolute pressure (tare corrected).
“PRHI”
The current upstream pressure value (corrected for tare) is returned in the current
pressure unit of measure.
Command:
“PRHI”
Reply:
“247.56 kPaa”
“DP”, “PRDP”, “PR”, “PRLO”
Read the last measured downstream absolute pressure (tare corrected).
“PRLO”
The current downstream pressure value (corrected for tare) is returned in the
current pressure unit of measure.
Command:
“PRLO”
Reply:
“224.67 kPaa”
“DP”, “PRDP”, “PR”, “PRHI”
Read or set the pressure display unit of measure.
“PUNIT=unit”
“PUNIT”
unit:
The text corresponding to the pressure unit of measure. The
pressure unit protocol is the same as the protocol used for front
panel entries and displays.
This command determines what unit of measure is used to display pressure.
Command:
“PUNIT=KA”
Reply:
“kPa a”
ERR# 7:
The unit is invalid.
3.5.8
Page 126
4. REMOTE OPERATION
PURGE(=)
Purpose
Syntax
Arguments
Remarks
Example
Errors
See Also
RANGE
Purpose
Syntax
Remarks
Example
See Also
RATE
Purpose
Syntax
Remarks
Example
See Also
RE
Purpose
Read the progress of or start a purge cycle.
“PURGE=period”
“PURGE”
Period:
The period of time over which to purge (1.. 999 seconds).
“0” aborts the purge cycle and returns to normal operation.
The purge cycle takes the specified time period to complete. The PURGE
command is used to first start the purge cycle, and then to query how many
seconds are left or if the cycle is complete. While the purge cycle is executing, a
‘b’ (“busy”) will appear in the 3rd character position of the “FR” and the “SR”
command replies. The “ABORT” command can also be used to abort a purge
cycle.
The “PURGE” command must be completed or aborted using the “ABORT”
command before performing another operation.
“PURGE=30”
Command:
“30 sec”
Reply:
“PURGE”
Command:
“12 sec” (purge cycle has 12 sec left)
Reply:
“OK”
(purge cycle is complete)
Reply:
ERR# 6:
The argument is invalid.
3.4.4.2 , “SR”; “ABORT”
Read the range designation of the active molbloc.
“RANGE”
The range designation of the active molbloc is returned in the flow units used to
define the range. Note that the effective molbloc range is dependent on the gas
being flowed and the molbloc pressure dependent calibration type. Do not
assume the usable range is equal to the range designation.
Command:
“RANGE”
Reply:
“10.00 sccm”
1.2.5, 3.5.1, Table 23, Table 24, “MOLBLOC”, “DEVICE=”
Read the next available rate of change of flow.
‘RATE”
The next available rate change of flow in the current flow unit of measure per
second is returned.
Command:
“RATE”
Reply:
“-0.01 sccm/s”
3.4.6.1
See Also
Read the value of Reynolds number representing the current flow through the
molbloc as calculated by the molbox1.
“RE”
The Reynolds number varies with the molbloc flow.
Command:
“RE”
Reply:
“82.342”
3.4.5
RES(=)
Purpose
Read or set the local flow display resolution.
Syntax
Remarks
Example
Syntax
“RES=n”
“RES”
Default
“RES=0.001%”
Arguments
n:
Remarks
The molbox’s front panel resolution can be specified with this command.
resolution of remote flow measurement replies are always 0.0001% FS.
Resolution in %FS (1% - 0.001%)
Example
Sent:
Query reply:
“RES=.01”
“0.010%”
Errors
ERR# 6:
The argument was out of bounds.
See Also
3.4.9
Page 127
The
© 1995 - 2007 DH Instruments, a Fluke Company
MOLBOX1™ OPERATION AND MAINTENANCE MANUAL
READYCK(=)
Purpose
Read or set a flag that is cleared by a Not Ready condition.
Syntax
“READYCK=1”
“READYCK”
Defaults
“READYCK=1”
Remarks
The internal ready check flag is cleared whenever the molbox1 reaches a
Not Ready (NR) condition. The "READYCK" command will return the status of this
flag. This flag can be set only by sending the "READYCK=1" command while the
molbox1 is in a Ready (<*>) condition. If you send the "READYCK=1" command when
the molbox1 is in a Not Ready (NR) condition, the reply will be "READYCK=0".
If you set READYCK=1 when the molbox1 achieves a Ready (R) condition, you
can use READYCK later to determine if a Not Ready (NR) condition has occurred.
If NR has occurred, READYCK will return "0". If NR has not occurred, READYCK
will return "1".
“READYCK=1” (Set the flag)
Example
Command:
“READYCK=1”
Reply:
“READYCK”
(Query for flag status)
Command:
“READYCK=1” (Has been ready since setting flag)
Reply:
Errors
ERR# 6:
The argument is not a 1.
See Also
3.1.3, “SR”
REMOTE
Purpose
Syntax
Remarks
Example
See Also
RESET
Purpose
Syntax
Remarks
Example
See Also
SN
Purpose
Syntax
Remarks
Example
See Also
SR
Purpose
Syntax
Remarks
Example
See Also
© 1995 - 2007 DH Instruments, a Fluke Company
Enable remote local lockout operation.
“REMOTE”
A REMOTE command deactivates the front panel. All front panel controls will be disabled.
The REMOTE command can only be canceled by a LOCAL command or by turning
OFF the molbox1 power then re-applying it.
Command:
“REMOTE”
Reply:
“REMOTE”
“LOCAL”
Reset the molbox1 to the default operating parameters.
“RESET”
The RESET command can be given to return certain molbox1 settings to a default state.
This reset corresponds to the RESET - SETS function from the front panel. The reset
process can take up to 10 seconds to complete, so the user must wait this time
interval before attempting to communicate to the molbox1 again.
Command:
“RESET”
Reply:
“RESET”
3.6.1
Read the serial number of the molbox1.
“SN”
Each molbox1 is serialized. This serial number is also imprinted on the product label on
the bottom of the molbox1 and is displayed in the power up introductory screen.
Command:
“SN”
Reply:
“SN”
3.6.5.2
Read the next available ready status.
“SR”
The current Ready/Not Ready status can be read directly using this command. If the
reply is "NR" then the flow is Not Ready within the limits set by the stability settings.
If the reply is "R" then the flow is Ready within the limits. The status is replied
when the next flow measurement is finished.
An "a" optionally appears as the third character if the molbox1 is currently
executing an averaging cycle. An "r" optionally appears as the third character if the
molbloc flow is over the maximum Reynolds number of 1 200 allowed for a valid
measurement. A “b” appears as the third character if the molbox1 is busy with a
tare, leak check or purge cycle which does not allow normal operation.
If a molbloc-S is active, a “P” appears as the third character if the BPR is too high
for a valid measurement.
“SR ”
Command:
“R ”
(Flow measurement is ready)
Reply:
“NR ” (Flow measurement is not ready)
Reply:
“R a” (average cycle is executing)
Reply:
“R b” (tare, leak check or purge cycle is executing)
Reply:
“NRP” (BPR is too high for a valid measurement)
3.1.3, “FA”, “FR”, “READYCK”, “SS”, “TARESET”, “PURGE”, “LEAKCK”
Page 128
4. REMOTE OPERATION
SS(%)
Purpose
Syntax
Defaults
Arguments
Remarks
Example
Errors
See Also
Read or set the flow stability required for a Ready condition to occur (flow unit/s).
“SS=stab”
“SS”
“SS%=stab%”
“SS%”
“SS=0.1 sccm”
stab:
The flow stability in flow unit/sec.
stab%:
The flow stability in % FS of the active molbloc.
The stability setting determines whether the flow is ready or not ready. Stability is
set in terms of flow or % FS. It is always stored in terms of flow, so the % FS value
will change if the molbloc range changes. If the rate of change of flow is greater
than the current setting, then the status is Not Ready.
“SS=.2”
Command:
“0.20 sccm”
Reply:
“SS%=.1”
Command:
“0.1000 %”
Reply:
ERR# 6:
The argument is invalid.
3.1.3, 3.5.2, “READYCK”, “SR”
STDRES(=)
Purpose
Read or set the PRT measurement system auto-calibration reference resistor
values .
Syntax
“STDRES=R100, R110”
“STDRES”
Defaults
“STDRES = 100.0000, 110.0000”
Arguments R100:
The actual value of the 100Ω reference resistor.
R110:
The actual value of the 110Ω reference resistor.
Remarks
These values are stored in the molbox’s factory data area, and should not be
routinely changed due to a limitation of the number of changes allowed (100,000
changes) before the factory data area is subject to failure.
Example
Sent:
“STDRES=100.002, 109.998”
Reply:
“ 100.0020 Ohms, 109.9980 Ohms”
See Also
5.4
TARE
Purpose
Syntax
Remarks
Example
Errors
See Also
Read the current tare conditions and the current tare.
“TARE”
The user should set the molbox1 valves to the tare condition (see “TARESETUP”)
and check the tare conditions using this command before taring the internal
transducers (see “TARESET”).
The returned data will allow the user to determine if the current conditions will allow
a valid tare. The reply contains three fields which are separated by commas.
The first field starts with an "R" if the system is ready to tare or else an "NR". The "R"
must be present to tare the transducers. The system is ready to tare only if the
current difference in pressure [Pa] between the up and down stream RPTs without
tare is below 3 000 Pa. The actual pressure rate of change in Pa/sec follows this text.
The second field displays the current difference in pressure [Pa] between the up and
down stream RPTs without tare. The third field shows the last tare value. All returned
values are in Pascal [Pa]. You cannot be in A+B or A/B modes when taring.
The normal order of remote commands for a tare operation:
“TARESETUP=UP” or “TARESETUP=DN” configures the molbox1 for a tare.
“TARE” queries the molbox1 for current conditions until it is ready for tare.
“TARESET” tares the molbox1 when the “TARE” query has shown it is ready.
“TARESETUP=OFF” returns the molbox1 to normal measurement mode.
Command:
“TARE”
Reply:
“R 0 Pa/s, 115.2 Pa, 108.1 Pa”
ERR# 6:
An argument is invalid.
ERR# 52:
Cannot tare in A+B or A/B mode.
3.4.4.1, “TARESET”, “TARESETUP”
Page 129
© 1995 - 2007 DH Instruments, a Fluke Company
MOLBOX1™ OPERATION AND MAINTENANCE MANUAL
TARESETUP(=)
Purpose
To prepare the molbox1 to be tared and to return the unit to normal operation after
a tare has been completed.
Syntax
“TARESETUP=mode
“TARESETUP”
Defaults
“TARESETUP=OFF”
“OFF”. Allows normal operation of the molbox1.
Arguments mode:
“UP”. Connects both of the absolute RPTs to the upstream
pressure.
“DN”. Connects both of the absolute RPTs to the downstream
pressure.
Remarks
Before the molbox1 can be tared, the “TARESETUP” command must be used to
configure the internal RPT connections properly. After the tare operation is complete,
the “TARESETUP” command must again be used to restore the molbox1 to
normal operation. The “ABORT” command can also return operation to normal.
The normal order of remote commands for a tare operation:
“TARESETUP=UP” or “TARESETUP=DN” configures the molbox1 for a tare.
“TARE” queries the molbox1 for current conditions until it is ready for tare.
“TARESET” tares the molbox1 when the “TARE” query has shown it is ready.
“TARESETUP=OFF” returns the molbox1 to normal measurement mode.
Example
Command:
“TARESETUP=UP”
Reply:
“UP”
Errors
ERR# 6:
An argument is invalid.
ERR# 52:
Cannot tare in A+B or A/B mode.
See Also
3.4.4.1, “TARE”, “TARESET”; “ABORT”
TARESET(=)
Purpose
To automatically tare the upstream and downstream RPT or set the tare to a user
defined value.
Syntax
“TARESET=tare
“TARESET”
Defaults
“TARESET=0”
Arguments tare:
The tare value (-9999 to 9999 Pa).
Remarks
“TARESET” will automatically tare the molbox1 only if the tare results are within the
limits given (see the “TARE” command). Use the “TARESETUP” command to prepare
the unit to be tared, and the “TARE” command to check if conditions are valid.
After you have completed taring the unit, use the “TARESETUP=OFF” command or
the “ABORT” command to return the unit to normal operating conditions. You can
also manually set the tare value using the “TARESET=tare” command. All pressure
values are always in Pascal [Pa]. While the tare cycle is executing, a ‘b’ (“busy”)
will appear in the third character position of the “FR” and the “SR” command replies.
The normal order of remote commands for a tare operation:
“TARESETUP=UP” or “TARESETUP=DN” configures the molbox1 for a tare.
“TARE” queries the molbox1 for current conditions until it is ready for tare.
“TARESET” tares the molbox1 when the “TARE” query has shown it is ready.
“TARESETUP=OFF” returns the molbox1 to normal measurement mode.
NOTE: This command typically takes 5 to 7 seconds to complete if performing a
tare (no arguments given).
“TARESET”
Example
Command:
“66 Pa”
Reply:
“66 Pa, 7 Pa”
Reply:
Errors
ERR# 6:
An argument is invalid.
ERR# 25:
The tare values exceed the tare limit of 3 000 Pa.
ERR# 52:
Cannot tare in A+B or A/B mode.
See Also
3.4.4.1 , “TARE”, “TARESETUP”, “ABORT”
TEMP
Purpose
Syntax
Remarks
Example
Errors
See Also
© 1995 - 2007 DH Instruments, a Fluke Company
Read the temperature of the active molbloc in the current unit of measure.
“TEMP”
The molbloc temperature is returned in the current temperature units. The average
temperature, upstream temperature and downstream temperature is returned (in
that order). An error will be returned if there is a problem reading the molbloc
PRTs.
Command:
“TEMP”
Reply:
“17.85 C, 17.84 C, 17.86 C”
ERR# 37:
There is an error in the molbox1 PRT measurement.
3.2.5, 5.4, 3.4.5 “TUNIT”, “OHMS”
Page 130
4. REMOTE OPERATION
TIME(=)
Purpose
Syntax
Arguments
Example
Errors
See Also
TOTAL(=)
Purpose
Syntax
Arguments
Remarks
Example
Errors
See Also
TUNIT
Purpose
Syntax
Arguments
Remarks
Example
Errors
See Also
UDU(=)
Purpose
Syntax
Arguments
Defaults
Example
Errors
See Also
Read or set the internal clock time.
“TIME”
“TIME=hh:mm:m
hh:mmxs:
The time to set in the format where hh is the hours from 1 to 12,
mm is the minutes from 1 to 59 followed by “am” or “pm”.
Command:
“TIME=1:22am”
Reply:
“01:22am”
ERR# 7:
The time given is invalid.
3.6.5.3
Read the progress of or start a new totalize cycle.
“TOTAL=period”
“TOTAL”
period:
The period to totalize 00:00:01 to 99:59:59 (HH:MM:SS).
“0” stops the totalize cycle before it is complete.
The totalizing cycle accumulates the total mass or volume flowed over a set period,
or the user can stop the cycle early if desired to use a shorter period than specified.
The reply to a “TOTAL” query provides the current total, and the elapsed time
period in the HH:MM:SS format. The cycle is complete when the total flow is
preceded by ‘R’ (Ready). If the unit is actively totalizing, an “NR” (Not Ready)
proceeds the total flow.
Command:
“TOTAL=00:10:00”
Reply:
“NR 0.0000 ucc, 00:00:00” (new cycle has started)
“TOTAL”
Command:
”NR 5.2347 ucc, 00:08:21” (cycle has run 8 min, 21 sec)
Reply:
”R 6.2634 ucc, 00:10:00” (cycle is complete)
Reply:
Command:
“TOTAL=0”
Reply:
”R 5.2347 ucc, 00:08:21” (cycle has completed early)
ERR# 6:
The argument is invalid.
3.4.6.4
Read or set the molbloc temperature unit of measure.
“TUNIT=unit”
“TUNIT”
unit:
‘C’ for Celsius or ‘F’ for Fahrenheit.
The temperature unit is used for reporting the molbloc temperature, and for setting
various other temperature settings.
Command:
“TUNIT”
Reply:
“C”
ERR# 6:
The unit argument is invalid.
3.5.9, “TEMP”
Read or set the user definable pressure unit.
“UDU”
“UDU=text, coef”
text:
The text to use to identify the unit. It can be up to four characters wide.
This will be the text used to specify the unit if selecting it remotely,
and that appears on the molbox1.
coef:
The coefficient to convert Pascal [Pa] to the user unit. The pressure
(in Pa) will be multiplied by this coefficient before being displayed.
“UDU=UNIT, 1”
Command:
“UDU=Bar2, .00001”
Reply:
“Bar2, 0.000010”
ERR# 2:
The text argument is longer than four characters.
ERR# 6:
The coef argument is invalid.
3.5.8, “PUNIT”
Page 131
© 1995 - 2007 DH Instruments, a Fluke Company
MOLBOX1™ OPERATION AND MAINTENANCE MANUAL
UL(=)
Purpose
Syntax
Defaults
Arguments
Remarks
Example
Errors
See Also
Read or set the upper limit for the internal pressure transducers.
“UL=upperlimit”
“UL”
“UL=630.00 kPa”
upperlimit:
The upper limit in the current pressure units (0 to 500 kPa).
The upper limit sets the point in which the molbox1 reacts to protect the internal
transducers; It is in the current pressure units.
Command:
“UL=350”
Reply:
“350.000 kPa”
ERR# 6:
The upperlimit argument is invalid.
3.6.3
USERCAL(=)
Purpose
Read or set the user flow measurement adjustment.
Syntax
“USERCAL=adder, mult”
“USERCAL”
Defaults
“USERCAL=0, 1”
Arguments Adder:
The flow adder in the current flow unit and gas type (0 to FS).
Mult:
The flow multiplier (0.1 to 2).
Remarks
The user definable adjustment lets the user modify the measured flow. The adder
and multiplier are separated by a comma. The adder is in the current flow unit.
Example
Command:
“USERCAL=.58,.995”
Reply:
“0.58 sccm, 0.995000”
Errors
ERR# 6:
The adder or multiplier argument is invalid.
See Also
3.5.3
UTEMP
Purpose
Syntax
Defaults
Arguments
Remarks
Example
See Also
VALVE(=)
Purpose
Syntax
Arguments
Remarks
Example
Errors
See Also
VER
Purpose
Syntax
Remarks
Example
© 1995 - 2007 DH Instruments, a Fluke Company
Read or set the temperature reference used for the volumetrically based mass flow
unit with user defined reference temperature.
“UTEMP=temp”
“UTEMP”
“UTEMP=0” (°C)
Temp:
The reference temperature in the current temperature unit of
measure.
This temperature reference is used by the user defined units.
Command:
“UTEMP=20”
Reply:
“20.00 C”
3.4.3.1, 3.4.3.4, “FUNIT”, “TUNIT”
This command is obsolete and should not be used in new designs. The TARESETUP
and PURGE commands should be used instead for special valve operations.
“VALVE=xxx”
“VALVE”
xxx:
The driver bitfield.
This command is obsolete.
Command:
“VALVE=5”
Reply:
“5”
ERR# 6:
The xxx argument is not between 0 and 255.
“TARESETUP”, “PURGE”
Read the molbox1 version.
“VER”
The software version of the molbox1 can be read. This is useful for checking for
the presence of the molbox1 and for reference purposes.
Command:
“VER”
Reply:
“DH INSTRUMENTS, INC molbox1 Ver5.10 ”
Page 132
4. REMOTE OPERATION
VLM(=)
Purpose
Syntax
Defaults
Arguments
Remarks
Example
Errors
See Also
VIN
Purpose
Syntax
Remarks
Example
Errors
See Also
VOUT(=)
Purpose
Syntax
Defaults
Arguments
Remarks
Example
Errors
See Also
VSENSE
Purpose
Syntax
Remarks
Example
Errors
See Also
VSUPPLY
Purpose
Syntax
Remarks
Example
Read or set the volume flow unit of measure pressure temperature conditions.
“VLM=pres(,temp)”
“VLM”
“VLM=101.325 kPaa, 20°C”
pres:
The user defined pressure in the current pressure unit.
Temp:
The user defined temperature in the current temperature unit. If this
field is omitted, and just the pressure is given, then the molbloc
temperature will be used as temperature.
The flow volume units "ccm", "lm", "lh", "m3m", "m3h", "cfm" and "cfh" require
pressure and a temperature conditions to be specified by the user.
“VLM=200”
Command:
“200.00 kPaa” (molbloc temp will be used)
Reply:
“VLM=200, 15”
Command:
Reply:
“200.00 kPaa, 15°C” (user defined temp will be used)
ERR# 6:
One of the arguments is invalid.
3.4.3.1, 3.4.3.4 “FUNIT”
Read the MFC measurement voltage if in voltage mode.
“VIN”
The optional MFC interface can measure voltage sent from an MFC. The molbox1
must be in voltage mode before this can be done. The returned data is always in “v”.
Command:
“VIN”
Reply:
“1.982 V”
3.4.8, 7.3, “MFCCH”, “VOUT(=)”
Send a voltage to the MFC if in voltage mode.
“VOUT=voltage”
“VOUT”
“VOUT=0”
voltage:
The voltage to be sent to the MFC (0 to 5.5 V).
The optional MFC interface can set a voltage sent to an MFC. The molbox1 must
be in voltage mode before this can be done (see the “MFCCH” command). The data
is always in Volts. This command does not change the regulation target set point
for the MFC.
Command:
“VOUT=3”
Reply:
“3.000 V”
The Volts argument is invalid.
ERR# 6:
The MFC option is not installed or is not enabled.
ERR# 10:
The molbox1 is not in current mode.
ERR# 15:
3.4.8, 7.3, “MFCCH”, “VIN”
Read the voltage sensed at the DUT set terminal.
“VSENSE”
The optional MFC interface uses a voltage sense line to measure the voltage being
sent to an external MFC at the MFC. This sense voltage is used to re-adjust the
voltage sent to the MFC to compensate for line losses.
Command:
“VSENSE”
Reply:
“3.002 V”
3.4.8, 7.3, “MFCCH”, “VIN”, “VOUT”
Read the current ±15 Volt MFC supply voltage.
“VSUPPLY”
The optional MFC interface provides a ±15 Volt supply. These two measurements
are referenced to the MFC supply common, and are sensed in the molbox1.
Command:
“VSUPPLY”
Reply:
“+14.982 V, -15.231 V”
See Also
3.4.8, 7.3, “MFCCH”, “VIN”, “VOUT”
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VVALTEST
Purpose
Read the voltage at the optional MFC interface valve test input.
Syntax
“VVALTEST”
Remarks
The optional MFC interface provides an input to measure the MFC valve test voltage.
This measurement is referenced to the MFC -15 Volt supply.
Example
Command:
“VVALTEST”
Reply:
“5.32 V”
See Also
3.4.8, 7.3, “MFCCH”, “VIN”, “VOUT”
ZOFFSET:HI(=) and ZOFFSET:LO(=)
Purpose
Read or set the AutoZ pressure offset (Poffset) for the high (“HI”) or low (“LO”) RPT .
“ZOFFSET:HI =offset”
Command
“ZOFFSET:LO =offset”
:
“ZOFFSET:HI”
“ZOFFSET:LO”
Query:
Defaults
“ZOFFSET:HI = 0.0”
“ZOFFSET:LO = 0.0”
Arguments offset:
The RPT pressure offset (“Poffset”) in Pa.
Remarks
The pressure offset (Poffset) for the specified RPT (HI or Lo) can be accessed with
this command. Using this program message overwrites the current offset, so caution
must be used. Changes made using this program message take effect immediately.
Example
Sent:
“ZOFFSET:LO=2.1”
Reply:
“ 2.10 Pa”
Errors
ERR# 6:
One of the arguments is out of range.
See Also
3.4.4.4, “AUTOZERO” command
4.4
STATUS SYSTEM
The status system includes the status reporting system which reports general molbox1 events. The user
can select which molbox1 events will cause a status change event. These events are then reported to
the status system (bit7 and bit3 of the status byte register), which also must be configured for the STATus
subsystem to generate the service requests described in Section 4.4.1, Status Reporting System.
There are two 16 bit event registers that make up the top layer of the status subsystem. The OPERation
status register handles conditions that are normal for the molbox1. The QUEStionable status register
handles events that could cause measurements to be made under questionable conditions.
Other registers layered below these two registers provide the structure necessary to handle the two RPT
channels and to enable the events and event transitions. Bit15 of all of these registers is not used
because bit15 represents a sign bit on some computer systems.
4.4.1
STATUS REPORTING SYSTEM
The molbox1 status reporting system is used to track and report system status and errors.
The status subsystem is layered under and reports to the status reporting system. It follows
the model of the IEEE Std 488.2 and works for the COM1 and the IEEE-488 port with slight differences.
The molbox1 can be programmed to respond to various status conditions by asserting the
SRQ of the IEEE-488 interface. The COM1 port cannot be supported in this manner, so polling
must be used.
4.4.1.1
STATUS BYTE REGISTER
The molbox1 contains an 8 bit status byte register that reflects the general status
of the molbox1.
Table 32. Status Byte Register
OPER
(128)
RQS/MSS
(64)
© 1995 - 2007 DH Instruments, a Fluke Company
ESB
(32)
Page 134
MAV
(16)
N/A
(8)
ERROR
(4)
N/A
(2)
RSR
(1)
4. REMOTE OPERATION
This register is affected by the molbox1 reply output queue, the error queue, the
Standard Event Status register, the Ready Event Status register and the
STATus subsystem.
Status Byte Register
(“∗STB?” or ”∗SRE n”)
OPER
←←←
Bit7 (128)
RQS/MSS
Bit6 (64)
ESB
Bit5 (32)
MAV
Bit4 (16)
N/A
Bit3 (8)
ERROR
Bit2 (4)
←←←
←←←
←←←
OPERation summary bit
Standard Event Status Register
(“∗ESR?” or “∗ESE n”)
PON
URQ
CMD
EXE
DDE
QYE
Bit7
Bit6
Bit5
Bit4
Bit3
Bit2
OUTPUT
QUEUE
RQC
Bit1
OPC
Bit0
ERROR
QUEUE
N/A
Bit1 (2)
N/A
Bit0 (1)
Figure 13. Status Byte Register
The status byte register can be read using the “*STB?” query, or by performing a
serial poll on the IEEE-488 bus. If you read this using a serial poll then bit 6 is
the RQS. If the “∗STB?” query is used, then bit 6 is the MSS bit. All of the other
bits are common to both types of query.
Each of these status bits can cause a SRQ to occur. The Service Request
Enable Register (“∗SRE” program message ) determines which of these flags are
able to assert the SRQ line. This enable register has a matching set of bits that each
will enable the designated bit to cause a SRQ, except for the RQS/MSS bit(s)
which cannot cause a SRQ. If you set this register to 20 ($14 hex), an SRQ will occur
if the MAV or the ERROR bit are set. The description of these bits are given as:
•
OPER: OPERational event register summary bit (Bit 7)
This bit is not supported by the molbox1.
•
RQS: Requested Service (Bit 6)
Indicates that the SRQ line of the IEEE-488 interface has been asserted by
the molbox1. This bit is cleared when a serial poll is performed on the molbox1,
and is a part of the status byte register when read using a serial poll. This bit
does not apply if the COM1 port is being used.
•
MSS: Master Summary Status (Bit 6)
Indicates that an event or events occurred that caused the molbox1 to
request service from the Host, much like the RQS bit. Unlike the RQS bit, it
is READ ONLY and can be only cleared when the event(s) that caused the
service request are cleared.
•
ESB: Event Summary Bit (Bit 5)
Indicates if an enabled bit in the Standard Event Status Register became set.
(See Section 4.4.1.2.)
•
MAV: Message Available Bit (Bit 4)
Indicates that at least one reply message is waiting in the molbox1 IEEE-488
output queue.
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•
ERR: Error Queue not empty (Bit 2)
Indicates that at least one command error message is waiting in the molbox1
IEEE-488 error message queue. Use the “SYSTem:ERRor?” query to get
this message.
4.4.1.2
STANDARD EVENT REGISTER
The molbox1 contains an 8 bit Standard event register that reflects specific
molbox1 events that are not RPT dependent. Enabled events in this register will
set or clear the ESB bit of the status byte register.
Table 33. Standard Event Register
PON
(128)
URQ
(64)
CMD
(32)
EXE
(16)
DDE
(8)
QYE
(4)
RQC
(2)
OPC
(1)
This register can be read using the “*ESR?” query. Each of these status bits can set
the ESB bit of the status byte register, causing a SRQ to occur IF the ESB bit is
enabled to do so. The Standard Event Status Enable Register (“∗ESE” program message)
determines which of these flags are able to assert the ESB bit. The description
of these bits are given as:
•
PON: Power On (Bit 7)
Indicates that the molbox1 power has been cycled since the last time this bit
was read or cleared.
•
URQ: User Request (Bit 6)
Indicates that the molbox1 was set to local operation manually from the front
panel by the user (pressing the ESC key).
•
CMD: Command Error (Bit 5)
Indicates that a remote command error has occurred. A command error is
typically a syntax error in the use of a correct program message.
•
EXE: Execution Error (Bit 4)
Indicates if a remote program message cannot be processed due to device
related condition.
•
DDE: Device Dependent Error (Bit 3)
Indicates that an internal error has occurred in the molbox1 (e.g., a transducer
time-out).
•
QYE: Query Error (Bit 2)
Indicates that an error has occurred in the protocol for program message
communications. This is typically caused by a program message being sent
to the molbox1 without reading a waiting reply.
•
RQC: Request Control (Bit 1)
This bit is not supported as the molbox1 cannot become the active controller
in charge.
•
OPC: Operation Complete (Bit 0)
Indicates that the molbox1 has completed all requested functions.
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5. MAINTENANCE, ADJUSTMENTS AND CALIBRATION
5.
MAINTENANCE,
ADJUSTMENTS AND
CALIBRATION
5.1
PRODUCT OVERVIEW
molbox1 was designed for maintenance free operation. No maintenance is required other than:
•
Taring of Reference Pressure Transducers (RPTs) to zero differential for molbloc-L operation:
This function is not a separate MAINTENANCE function or automatic molbox1 activity, it is part of
regular operation (see Section 3.4.4.1).
•
AutoZero of Reference Pressure Transducers (RPTs): Regular rezeroing of the RPTs absolute
measurement mode to a barometric reference standard using the AutoZ function is recommended
(see Section 3.4.4.4).
•
Reference Pressures Transducer (RPT) Calibration: An annual recalibration cycle is recommended.
See Section 5.2 for RPT calibration instructions.
•
Optional MFC Control Function Verification: The stability of the MFC control function analog
voltage and current measurements over time is dependent upon the conditions of use. The MFC control
function accuracy should be verified regularly. See Section 5.3 for instructions.
•
Ohmic Measurement System Verification: A five year verification interval is recommended. See
Section 5.4 for instructions.
•
molbloc Calibration: molblocs can be calibrated separately from the molbox1. A one year recalibration
cycle is recommended. Calibration of a molbloc consists of comparing the mass flow measured by
the combination of the molbloc and a calibrated molbox to a suitable mass flow standard flowing the
gas for which the calibration is being performed. Since the molbloc is a static, stainless steel element,
characterized by proprietary calibration coefficients determined in the original factory calibration, an out of
tolerance molbloc is usually considered to require repair. For facilities requiring the capability to
adjust molblocs to agree with their mass flow standard, CalTool for molbloc software is available.
This section provides information on maintenance, adjustment, calibration procedures and recommended
overhaul procedures.
Calibration, maintenance and repair services for molbox1 are offered by DHI Authorized
Service Providers (see Section 7.4).
molbox1 is a sophisticated measuring instrument with advanced on-board features and functions.
Before assuming that unexpected behavior is caused by a system defect or breakdown, use this
manual and other training facilities to become thoroughly familiar with molbox1 operation. For rapid
assistance in specific situations and other troubleshooting information, see Section 6.
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molbox1 is covered by a limited 1 year warranty (see Section 7.4). Unauthorized service or repair during
the warranty period is undertaken at the owner's risk and may cause damage that is NOT covered
under product warranty and/or may void the product warranty.
5.2
CALIBRATION OF REFERENCE PRESSURE
TRANSDUCERS (RPTS)
5.2.1
PRINCIPLE
molbox1 has two nominally identical, absolute Reference Pressure Transducers (RPTs) used
to measure molbloc upstream and downstream pressure.
To calibrate an RPT, pressure from a pressure standard is applied to the RPTs at ascending
and descending pressure increments over the RPT range. The pressure defined by the
standard and the corresponding RPT readings are recorded at each point. After all of the
pressures have been applied and recorded, adjustments are made to fit the RPT pressure
readings to the standard. Fitting the readings means performing a least squares linear
regression to arrive at the lowest value of the residual of errors of the transducer relative to
the standard. The transducer readings are adjusted by user settable coefficients: PA (a pressure
adder or offset) and PM (a pressure multiplier or span set) (see Section 5.2.1.1).
molbox1 is delivered with an interactive reference pressure transducer (RPT) calibration
utility software program that steps the operator through the complete RPT calibration
procedure including applying pressures, collecting data automatically, calculating new PA
and PM values, previewing the results of the new calibration and activating the results of the
new calibration (see the CalTool for RPTs program and documentation provided on the
General Accessories disk delivered with molbox1). molbox1 also provides complete local
and remote access to RPT calibration coefficients so that RPT calibrations can be performed
without using CalTool software if desired (see Section 5.2.5).
CalTool for RPTs software provided with the molbox1 supports the calibration process of
molbox1 RPTs. The CalTool program and its manual are provided on the General
Accessories Disk with the new molbox1. Most users should use CalTool software to
assist in the calibration of molbox1 RPTs.
5.2.1.1
PA AND PM COEFFICIENTS
The coefficients used to adjust RPT readings are designated PA (a pressure
adder or offset) and PM (a pressure multiplier or span set). The coefficients
affect the RPT reading following:
Corrected reading = (uncorrected reading • PM) + PA
PA is expressed in pressure (always the SI unit, Pascal [Pa]).
PM is dimensionless.
There are individual PA and PM values for each of molbox1's two RPTs. The PA and PM
values currently in use for each RPT can be viewed in the CALIBRATION function.
If adjustments are necessary when calibrating an RPT, the adjustments are made by
adjusting the PA and PM values.
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5. MAINTENANCE, ADJUSTMENTS AND CALIBRATION
As editing PA and PM values will change RPT calibration, they should only be
edited by qualified personnel as part of the calibration process. Caution should
be taken to avoid accidental editing. For information on preventing access
to calibration information, see Section 0.
A new molbox1 is delivered with all PA and PM values set to zero and 1. This does
NOT mean that the molbox1 has NOT been calibrated. For the original
factory calibration, privileged factory coefficients are used for calibration
adjustment. This allows a new molbox1 to be delivered with “virgin”
calibration coefficients of PA = 0 and PM = 1.
5.2.2
EQUIPMENT REQUIRED
To calibrate molbox1’s absolute reference pressure transducers (RPTs) to factory
specifications, a gas operated pressure standard with the following characteristics
are required:
•
Able to apply absolute pressure in 20 % increments between 50 and 600 kPa (7.25
and 87 psia) for molbox1 A700K and 20 to 200 kPa (3 to 30 psia) for molbox1 A350K.
It is NOT necessary that the reference pressure standard used apply precisely the
nominal pressure value of the calibration points as long as the exact value of the applied
pressure is known. A different range may be used if it is know the molbox1 will not be
used outside of the different range.
•
Measurement uncertainty (accuracy) of ± 0.005 % of reading or better, if normal
molbox1 flow measurement uncertainty specifications are to be obtained. A standard with
higher measurement uncertainty may be used but molbox1 flow measurement uncertainty
may be proportionally degraded from published specifications.
Use only a clean dry gas source when calibrating molbox1 RPTs. Contaminating molbox1
with liquids can cause out of tolerance measurements and may require special factory cleaning.
DHI piston gauge Model PG7601 is recommended as the reference pressure standard for the
calibration of molbox1 RPTs. Contact DHI or your local representative for additional information.
5.2.3
SET-UP AND PREPARATION
To set-up and prepare the molbox1 for calibration:
n Set the molbox1 on a stable surface near the calibration standard at a height as close as
possible to the calibration standard's reference height. Consider the connections that
need to be made to the molbox1 rear panel pressure quick connectors and access to the
front panel display and keypad.
o Connect the calibration standard’s output to the molbox1 rear panel CHANNEL A UP
(HI) port. In <run> calibration mode (see Section 5.2.4.1), both absolute RPTs are
connected to the CHANNEL A UP (HI) port and isolated from the DOWN (LO) port. Use one
of the quick connector stems (DHI P/N 101889, equivalent to Swagelok SS-QM2-S-200)
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supplied with the molbox1 accessories to make the connection. The fitting on the quick
connector stem that must be mated to is a compression type for 1/8 in. tube.
5.2.4
VIEWING AND EDITING RPT READINGS AND
CALIBRATION INFORMATION
Editing RPT calibration information will affect molbox1 pressure measurements and can
cause out of tolerance flow measurements. RPT calibration information should only be
edited by qualified personnel as part of the calibration process. Caution should be taken
to avoid accidental editing. For information on preventing access to calibration
information see Section 3.6.2.
 PURPOSE
To read the output of molbox1 RPTs in calibration mode; view and edit the calibration
coefficients and calibration date.
 PRINCIPLE
The molbox1 CAL function contains all of the functions needed to perform RPT calibrations in
one menu area.
This includes:
•
Viewing molbox1 RPT outputs (pressure readings) directly without the tare (see Section
3.4.4.1) or head (see Section 3.6.8) applied and configured for application of calibration
pressures to run the calibration.
•
Viewing PA and PM calibration coefficients and the calibration date (see Section 5.2.1.1).
•
Editing PA and PM calibration coefficients and the calibration date (see Section 5.2.1.1).
See Sections 5.2.1 and 5.2.1.1 for information on molbox1 calibration coefficients (PA and
PM) and their proper use.
5.2.4.1

VIEWING RPT OUTPUTS
OPERATION
To view the molbox1 RPT outputs press
[SPECIAL], <4cal>, <1pres>, <1upstrm
or 2downstrm>, <1run>.
molbox1’s
internal valves operate to connect both
absolute RPTs to the upstream (HI)
pressure port (see Figure 14) and the
display is:
upstrm RPT
97.830 kPaa
dwnstrm
97.825
The upstream absolute RPT reading is on the left and the downstream absolute
reading is on the right. The values displayed are the RPT readings with the
current PA and PM calibration coefficients applied but WITHOUT the tare or
head applied (see Sections 3.4.4.1 and 3.6.8). Both the upstream and
downstream absolute RPTs are shown together because they are nominally
identical and are normally calibrated simultaneously.
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5. MAINTENANCE, ADJUSTMENTS AND CALIBRATION
Pressing [ESCAPE] or [ENTER] returns to the previous screen.
The RPT readings viewed under [SPECIAL], <4cal> DO NOT have the tare
(see Section 3.4.4.1) or a head (see Section 3.6.8) correction applied and are
valid for RPT calibrations. The RPT readings viewed by pressing [P&T] DO
have tare and head values applied and therefore should NOT be used for
taking RPT calibration data (see Section 3.4.4.1 for information on tare values).
1.
Channel A High Isolation: Open
2.
Channel A Low Isolation: Closed
3.
Channel B High Isolation: Closed
4.
Channel B Low Isolation: Closed
5.
Bypass: Open
Figure 14. molbox1
Internal Pneumatic Schematic - RUN UPSTREAM OR DOWNSTREAM
ABSOLUTE RPT CALIBRATION
5.2.4.2

VIEWING AND EDITING RPT PA, PM AND
CALIBRATION DATE
PURPOSE
To view or edit PA and PM calibration coefficients (see Section 5.2.1.1) and the
calibration date for each Reference Pressure Transducer (RPT).
Capability to view and edit the values of the reference resistors used by
molbox1’s ohmic measurement system (see Section 5.4) is also provided here.
This capability is normally used only by a DHI Authorized Service Provider.
Editing RPT, MFC and/or reference resistor calibration information will affect
molbox1 pressure and/or temperature measurements and can cause out-oftolerance flow measurements. Calibration information should only be edited
by qualified personnel as part of the calibration process. Caution should be
taken to avoid accidental editing. For information on preventing access to
calibration information see Section 0).

OPERATION
Press [SPECIAL], <4cal>, <1pres> and then <1upstrm> or <2dnstrm> to
specify the RPT to be viewed/edited. Finally select <2view> to view information
only or <3edit> to make changes to calibration information.
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The display is:
1.
Current adder (always in Pascal [Pa]). This is
an edit field if <3edit> was selected.
2.
Indication of which RPT calibration information
is being viewed/edited.
3.
This is an Current multiplier (dimensionless).
This is an edit field if <3edit> was selected.
PA:
PM:
0.0 dnstrm RPT
1.00000
If <3edit> was selected, edit the values of PA and PM as desired.
Pressing [ESCAPE] returns to the <1run 2view 3edit> screen without
making changes. Press [ENTER] to continue.
The display is:
1.
Current calibration date in YYYYMMDD
format for the selected RPT. This is an edit
field if <3edit> was selected. The default date
is 19800101..
dnstrm RPT cal date:
19990214
If <3edit> was selected, edit the calibration date as desired using a
YYYYMMDD format. Pressing [ESCAPE] returns to the <1run 2view 3edit>
screen without making changes. Press [ENTER] to continue. If <3edit> was
selected and changes have been made to PA, PM or the calibration date, a
confirmation screen is presented to <Activate changes>. Pressing [ESCAPE]
or selecting <1no> returns to the <1run 2view 3edit> screen without
making changes. Selecting <2yes> activates changes and returns to the <1run
2view 3edit> screen.
There is a specific calibration date for each RPT. Changing the calibration
date of one RPT does not change the other.
The value of PA is always in Pascal [Pa]. The value of PA must be entered in
the pressure unit Pascal [Pa]. If your calibration data is in a unit other than
Pascal, the calculated value of PA will be in the other unit and must be
converted to Pascal before it is entered (see Section 7.1.1 for pressure unit
conversions). The value of PM is dimensionless.
5.2.5
RPT CALIBRATION/ADJUSTMENT PROCEDURE
WITHOUT USING CALTOOL FOR RPT S SOFTWARE
Most users should use CalTool for RPTs software to assist in the calibration of molbox1
reference pressure transducers. CalTool for RPTs and its documentation are provided on
the General Accessories Disk delivered with molbox1. Whether using CalTool or not, before
proceeding to calibrate molbox1 RPTs, Sections 5.2.1 through 5.2.4 of this manual should
be reviewed thoroughly.
Both molbox1 RPTs are normally calibrated simultaneously.
procedure is:
© 1995 - 2007 DH Instruments, a Fluke Company
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The standard calibration
5. MAINTENANCE, ADJUSTMENTS AND CALIBRATION
n Set-up and prepare the molbox1 for calibration of the RPT(s) (see Sections 5.2.2, 5.2.3).
o Press [SPECIAL], <4cal>, <1pres>, <1upstrm>, <2view> to read and record the current
values of PA and PM for the upstream RPT. Then repeat the process selecting
<2dnstrm> to read and record the downstream RPT PA and PM (see Section 5.2.4.2).
p Press [SPECIAL], <4cal>, <1pres>, <1upstrm> or <2dnstrm>, <1run> to display the
real time pressure readings of the RPT(s) to be calibrated (see Section 5.2.4.1).
q Apply the calibration pressures to the RPT(s) recording the pressure applied by the
standard and the molbox1 RPT readings at each calibration point.
r The standard calibration range for the RPTs is 50 to 600 kPa absolute (7.25 to 87 psia)
for molbox1 A700K and 20 to 200 kPa (3 to 30 psia) for molbox1 A350K. Dwell at least
60 seconds after setting the reference pressure at each point to allow full stabilization.
The data recorded is the "as received" data for this calibration.
s Enter the calibration pressure and RPT readings for each point into a spreadsheet.
Calculate the "non-corrected" RPT readings by backing out the as received PA and PM
recorded in Step o above, following:
non-corrected reading = (corrected reading - PA)/PM
t Perform a best fit linear regression to find the offset and slope that best fit the noncorrected RPT readings to the calibration standard pressures. Most commercial
spreadsheet products have a standard function to perform a linear regression.
The offset, in Pascal [Pa], is the new value of PA, the slope is the new value of PM.
u Press [SPECIAL], <4cal>, <1pres>, <1upstrm> or <2dnstrm>, <2edit> to write the new
values of PA (always in Pascal) and PM and the new calibration date (YYYYMMDD) for
the RPT that is being calibrated.
v Calculate “as left data" for the calibration:
as left reading = (non-corrected reading • new PM) + new PA
w If desired, verify the as left data by rerunning the calibration with the new PA(s) and
PM(s) applied and checking that the disagreements between the calibration standard and
the RPT readings are in tolerance.
The value of PA must be entered in the pressure unit Pascal [Pa]. If the calibration data
is in a unit other than Pascal, the calculated value of PA will be in the other unit and must be
converted to Pascal before it is entered (see Section 7.1.1 for pressure unit conversions).
If you are not familiar or comfortable with the mathematics used for PA and PM
manipulation, it is recommended you verify the as left readings as suggested in Step w
above to provide practical confirmation of the integrity of the calculations. Note also
that the CalTool for RPTs software delivered with the molbox1 performs the necessary
calculations automatically.
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5.3
MFC CONTROL FUNCTION ADJUSTMENT
 PURPOSE
To verify and adjust the voltage and/or current measurements made by molbox1’s optional MFC control function.
Capability to view and edit the values of the voltage references resistors used by molbox1’s optional
MFC control function is also provided here. This capability is normally used only by a DHI Authorized
Service Provider.
 PRINCIPLE
molbox1 may be delivered with an optional MFC control function. The MFC control function allows
voltage of current set points to be applied to an MFC and voltage or current values to be read back from
an MFC or MFM.
The MFC control function is self-calibrating using on-board 5 and 10 V references. Voltage is converted
to current using a precision 250 Ω resistor.
The MFC control function signals are:
•
sense (V)
•
measure (V or mA)
•
valve (V)
•
negative power supply (V)
•
positive power supply (V)
•
set (V or mA)
See Section 1.2.4 for complete MFC control specifications.
Any of the MFC control signals can be adjusted using adders and multipliers in the same manner as the
pressure adders and multipliers used to adjust the molbox1 RPTs (see Section 5.2.1.1). The normal
procedure, however, is to use the molbox1 Analog Calibration software and cable provided with the
accessories of a molbox1 delivered with the optional MFC control function.
See Section 7.3 for MFC control function pin out details.
 OPERATION
This section describes the operation of the features available to adjust the optional molbox1 MFC
control function signals. The normal procedure for calibrating or adjusting these signals is to use the
molbox1 Analog Calibration software provide in the molbox1 accessories. The features described here
are made available for advanced users desiring to perform customized adjustments.
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5. MAINTENANCE, ADJUSTMENTS AND CALIBRATION
To access the MFC control function signal adders and multipliers pressure [SPECIAL], <4cal>, <3MFC>,
<1cal>. The display is:
Channel1:1sense 2meas
To access the MFC control function signal adders and multipliers
pressure [SPECIAL], <4cal>, <3MFC>, <1cal>. The display is:
3valve 4neg 5pos
6set
↓
Each selection displays the signal adder and multiplier. For certain signals, <1voltage> or <2current>
must be selected. In this case, there are separate and distinct adders and multipliers for voltage and
current readings.
<1sense>:
Set point sense. Voltage only.
<2meas>:
Output from the MFC or MFM sensor. Voltage or current.
<3valve>:
Valve test line to measure an MFC valve’s internal voltage. Voltage only.
<4neg>:
-15 VDC power supply. Voltage only.
<5pos>:
+15 VDC power supply. Voltage only.
<6set>:
MFC set point command. Voltage or current.
5.4
OHMIC MEASUREMENT SYSTEM VERIFICATION
 PURPOSE
To verify the measurements made by molbox1’s ohmic measurement system.
 PRINCIPLE
molbox1 includes an ohmic measurement system used to measure the resistance of the two Platinum
Resistance Thermometers (PRTs) mounted in molblocs. The temperature of the PRTs is calculated from
the resistance. The molbloc PRTs have nominal resistance at 0 °C of 100 Ω and a slope of 0.3896
following DIN Norm 43760. The measured resistance at 0 °C for each PRT is stored on the molbloc
EEPROM and read by the molbox1.
The ohmic measurement system self-calibrates using on-board 100 and 110 Ω reference resistors.
On molbox1 power up, an automated routine adjusts the ohmic measurement system relative to on-board,
reference resistor readings.
The on-board reference resistors used to calibrate the molbox1
measurement system have accuracy of ± 0.01 % and stability of ± 0.0025 % for one year, ± 0.005 % for
three years.
The self-calibration feature and the very high accuracy and stability of the reference resistors relative to
the accuracy tolerance on the molbox1 temperature measurements make it unnecessary to calibrate the
ohmic measurement system independently. It is good practice, however, to verify the ohmic
measurement system. This is most easily accomplished globally by connecting a known resistance value
to the measurement circuit where the molbloc PRTs are normally connected and verifying that the
molbox1 reads the correct corresponding temperature when that resistance is connected. Reference resistors
mounted in a molbloc simulator for easy connection to molbox1 using the normal molbloc connection
cable can be purchased from your DHI Sales Representative (molbloc simulator, 107 Ω, P/N 401232).
These are nominally 107 Ω resistors (roughly equivalent to a 20 °C measurement) whose values are
reported and can be measured independently if desired. The measured resistance of the reference resistors
and a value for resistance at 0 °C of 100 Ω are programmed on the simulator EEPROM. Using these values,
if the molbox1 ohmic measurement system and associated connections are working properly, when the
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MOLBOX1™ OPERATION AND MAINTENANCE MANUAL
simulator is connected the molbloc temperature indicated by molbox1 should equal the reference temperature
corresponding to the molbloc simulator reference resistor following:
The Reference temperature [°C] calculated from the actual reference resistor value is written on the
molbloc simulator. The temperature value read by the molbox1 when the molbloc simulator is connected
can be observed by pressing [P&T] (see Section 3.4.5). The disagreement between the reference
temperature and the molbloc indication should not exceed 0.05 °C.
Reference temperature [°C] = Reference resistor value [ Ω ] 100
0.3896
Because the ohmic measurement system is set up to measure two PRTs, there are two reference
resistors in the molbloc simulator. Their resistance is not identical so there are actually two reference
temperatures printed on the molbloc simulator and an average temperature which correspond to the
three temperatures on the molbox1 [P&T] temperature display (see Section 3.4.5).
 OPERATION
To verify the molbox1 ohmic measurement system proceed as follows:
n Connect a molbloc simulator P/N 401232 to the molbox1 and initialize it as if connecting a molbloc
(see Section 3.5.1).
o Press [P&T] and then [+/-] to display the molbox1 temperature measurement.
p Compare the three molbox1 temperature measurements (upstream, downstream and average) to the
calculated reference temperature values written on the molbloc simulator.
q If all disagreements between molbox1 indications and corresponding calculated reference
temperatures are less than 0.05 °C, the ohmic measurement system verification passed.
If any disagreement between a molbox1 indication and the corresponding calculated reference
temperature is greater than 0.05 °C, the ohmic measurement system verification failed.
Possible reasons for failure include:
•
faulty molbox1 internal reference resistor(s)
•
faulty molbox1 internal relays
•
faulty connections between molbox1 and the molbloc simulator
•
faulty molbloc simulator
Check the molbox1 to molbloc simulator connections and repeat the verification. If the out-of-tolerance
condition persists, the molbox1 and/or the molbloc simulator need service.
Pressing [SPECIAL] and selecting <4cal>, <2StdRes> provides access to view and edit the value of
molbox1’s two standard resistors. Altering these values can cause out of tolerance flow readings. In
normal circumstances, these values are only altered by the factory when a reference resistor is
replaced and they should not be altered by the user.
© 1995 - 2007 DH Instruments, a Fluke Company
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5. MAINTENANCE, ADJUSTMENTS AND CALIBRATION
5.5
RELOADING EMBEDDED SOFTWARE INTO molbox1
FLASH MEMORY
molbox1 uses FLASH memory. This allows the embedded software that controls molbox1 operations and
functions to be loaded into molbox1 over its COM1 port from a personal computer with a simple FLASH
loading utility.
To replace corrupted software or upgrade to a new version, your DHI Authorized Service Provider can
provide a FLASH memory loading utility along with a file containing the molbox1 embedded software.
These are also available for download from DHI’s worldwide web site, www.dhinstruments.com.
An electronic copy of the current Operation and Maintenance Manual is also available on the website.
If the embedded software you are using is suspected of a problem, record all symptoms and contact your
DHI Authorized Service Provider.
The DHI flash software loading utility, molbox1 embedded software and the current Operation and
Maintenance Manual are available for download from the “SOFTWARE” and “PRODUCTS” sections of
DHI’s worldwide web site at www.dhinstruments.com.
5.6
RELOADING molbloc EEPROM FILE
molbloc EEPROMs are programmed with:
•
A molbloc identifying header with range identifier, S/N and calibration date.
•
molbloc specific flow calibration coefficients for N2, and other gases if entered.
•
The resistance at 0 °C of the molbloc platinum resistance thermometers (PRTs).
If the molbloc EEPROM information becomes corrupted, molbox1 will be unable to read the molbloc
EEPROM and will display <NO BLOC> when attempting to initialize the molbloc.
DHI maintains files of the “as shipped” EEPROM contents of every molbloc delivered or recalibrated by
DHI. A molbloc EEPROM loading tool may be downloaded from the DHI worldwide web site
(www.dhinstruments.com) and specific molbloc files can be obtained by email. If you believe you have a
molbloc with a corrupted EEPROM, contact your DHI Authorized Service Provider for additional
information on the molbloc EEPROM loading tool and obtaining molbloc data files.
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MOLBOX1™ OPERATION AND MAINTENANCE MANUAL
5.7
OVERHAUL
If calibration of the Reference Pressure Transducers (RPTs) is included as part of the overhaul
procedure, the calibration procedure should be performed last as other overhaul procedures may
affect RPT calibration.
Any or all of the following items may be included as part of a system maintenance overhaul:
•
Clean front panel.
•
Check that rear mounted cooling fan operates when molbox1 is powered.
To open the molbox1 case, fold back the screw covers on the top and bottom of the case. Then
remove the eight case screws. Lift OFF the cover and bottom and place the molbox1 on its side for
easy access to internal components.
•
Disassemble valving assembly and clean valve components.
•
Check that internal screws, bolts and nuts are tight.
•
Perform molbox leak check (see Section 3.4.4.3) and verify operation by connecting a molbloc (see
Section 3.5.1).
•
Perform calibration of RPTs, if necessary (see Section 5.2).
•
Perform calibration of MFC control function if option present (see Section 5.3).
•
Verify ohmic measurement circuit if necessary (see Section 5.4).
© 1995 - 2007 DH Instruments, a Fluke Company
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6. TROUBLESHOOTING
6.
TROUBLESHOOTING
6.1
OVERVIEW
molbox1 is a sophisticated flow measuring instrument with advanced on-board features and functions.
Before assuming that unexpected behavior is caused by a system defect or breakdown, the operator
should use this manual and other training facilities to become thoroughly familiar with molbox1 operation.
This troubleshooting guide is intended as an aid in identifying the cause of unexpected molbox1 behavior
and determining whether the behavior is due to normal operation or an internal or external problem.
Identify the symptom or unexpected behavior you are observing from the SYMPTOM list in Table 34.
A PROBABLE CAUSE is provided and a SOLUTION is proposed including references to manual
sections that provide information that may be of assistance.
Table 34. Troubleshooting Checklist
SYMPTOM
PROBABLE CAUSE
SOLUTION
Will NOT power up.
Blown fuse.
Replace fuse.
Front panel keys seem to be
disabled.
"Remote" command has been sent
from a host computer locking out the
front panel keypad.
Operation is normal. Send "local" command
from host computer or cycle molbox1 power.
4.2.2
Front panel display is dim.
Screen saver option has activated.
Operation is normal. Press any key to
resume full screen power, adjust Screen
Saver activation time if desired. 3.6.5.1
Keypad presses make no sounds.
molbox1 does not support key pad
sounds.
Operation is normal.
Cannot access certain functions.
Display shows:
User level setting restricts access to
that function.
Operation is normal. Change user level or
consult system manager. 3.6.2
Cannot establish communication
over remote interface.
Computer and/or molbox1 interface not
correctly configured; incorrect or bad
interface cable.
Check and correct interface configurations
and cables if necessary. 3.6.6, 4.
molbox1 unable to read molbloc.
Cable not connected, molbloc data
corrupted.
Check cable connections, try another
molbloc, reload molbloc EEPROM. 3.5.1, 5.6
Displays <FATAL ERROR> or
<FATAL FAULT>.
Encountered unresolved internal
software conflict.
Cycle power to clear. Record conditions
leading up to event including the numbers
displayed when [ENTER] is pressed and
report to DHI Authorized Service Provider.
7.4
Displays <PRT ERROR>.
molbox1 has identified an unusually
large disagreement between the
temperature readings of the two
molbloc PRTs which may be due to
faulty molbloc PRTs or the molbox1
ohmic measurement system.
Connect a different molbloc. If the PRT error
is no longer present, the PRT system of the
original molbloc is probably damaged and
requires service. If the PRT error is present
with different molblocs, the molbloc/molbox
cable or molbox1 ohmic measurement
system is probably defective and requires
services. 3.4.5, 5.4
Display <TOUT> or <TIME-OUT>.
molbox1 is having an internal
communications problem with one or
both of its RPTs.
Turn power off and back on and/or execute
Reset – Sets being careful to reenter desired
settings afterwards. If problem persists,
molbox1 needs service. 3.6.1.1
Displays <NO BLOC>.
No molbloc is connected to molbox1 or
molbox1 is unable to read the molbloc
that is connected.
Verify proper electrical connection between
the molbox1 and a valid molbloc. If <NO
BLOC> is observed with one molbloc and not
others, molbloc is damaged and/or EEPROM
is corrupted. 3.5.1, 5.6
<ACCESS RESTRICTED>.
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SYMPTOM
PROBABLE CAUSE
SOLUTION
Displays <******> where a
numerical value should go.
Number to be displayed is too large for
allocated space. Usually due to an
erroneous setting or measurement
causing an out of limit value to be
calculated.
Check settings that may be causing an out of
limit measurement and adjust if necessary.
3.4.9, 3.4.1, 3.5.3
Bottom line of display has changed
and you want to change it back.
The DISPLAY function has been used
to change the display.
Use [DISPLAY] to set bottom line to desired
display. 3.4.6
Bottom line of display is blank.
DISPLAY mode is “clean”.
Operation is normal. Use [DISPLAY] to
change bottom line display if desired. 3.2.6.8,
3.4.6
Display is showing pressure values
and flashing, beeper is sounding
two second beeps.
Pressure applied to one or both of the
absolute RPTs is near overpressure.
Reduce pressure applied to upstream (HI)
and downstream (LO) molbloc pressure
connection ports and cycle power on
molbox1. 3.6.3.1, 1.2.2
Display is showing <OVERP!>.
One or both of the molbox RPTs has
been overpressured.
Remove the source of overpressure and
press [ENTER] to clear. Check molbox
RPTs for damage. 3.6.3.1, 1.2.2
Display is showing <BPR HI>
where the flow value should go.
molbox1 is in molbloc-S mode and the
ratio of downstream pressure to
upstream pressure (B\PR) is to high to
make a valid flow measurement.
Operation is normal. Increase flow to
increase upstream pressure and/or decrease
downstream pressure. 3.1.5, 3.6.9
Flow indication is flashing in
molbloc-L mode
Reynolds number is greater than 1300
Operation is normal. Indicates that flow is
beyond the molbloc-L range 1.2.5.1.2,
1.2.5.1.3, 3.2
Flow indication is flashing in
molbloc-S mode
Back pressure ratio is too high to
establish critical flow through the
molbloc-S.
Operation is normal. Increase molbloc-S
upstream pressure or reduce downstream
pressure to reduce BPR below the BPR limit
at the current Reynolds numbers. 3.1.5,
1.2.5.2.1.
Flow indicated by molbox1 never
becomes stable.
The flow through the molbloc is not
stable.
Molbox1 passively measures the flow
through the molbloc. It does not control flow.
Correct conditions that are causing unstable
flow.
A Ready (<*>) indication is never
achieved in molbloc-L mode.
Flow stability criterion is never being
met and or Reynolds number limit of 1
200 is being exceeded.
Adjust stability criterion or stabilize flow.
Reduce the flow rate and/or pressure to
reduce the Reynolds number of the flow.
3.5.2
Ready (<*>) indication and
measured flow value are flashing
in molbloc-L mode.
The flow is within the stability limit but
the Reynolds number of the flow
exceeds the maximum acceptable limit
of 1 200.
Operation is normal.
Pressure indicated by molbox1
never becomes stable.
There is a leak in the molbox1 and/or in
the system to which it and the molbloc
are connected.
Find and correct leak. Consider using
molbox1 LEAK CHECK functions. 3.4.4.3
Flow indication appears to be
grossly incorrect.
Your assumption of flow in the system
is grossly incorrect.
Check and adjust flow in the system.
Flow indication appears to be
grossly incorrect.
The molbloc connected to molbox1 has
been swapped without reinitialization so
molbox1 is still using characteristics
from a previous molbloc.
Reinitialize molbloc using [SETUP],
<1molbloc>. 3.5.1
In molbloc-S mode, there is no
flow through the molbloc but
molbox1 is indicating a large flow
value.
molbox1 is in BPR OFF mode and flow
is being calculated from upstream
absolute pressure without knowledge of
downstream pressure.
Behavior is normal. Consider BPR when
evaluating flow measurements when using
molbloc-S. Also consider changing BPR
mode to Auto or ON. 3.1.5, 3.6.9, 3.4.4.5
Flow indication appears to be
incorrect.
molbox/molbloc and/or the device you
are comparing it to are in tolerance but
you have not properly evaluated the
tolerance limits.
Determine flow measurement tolerance of
molbloc/molbox and device you are
comparing with. Evaluate “correctness”
relative to the combined tolerance of the two.
1.2.5.
Flow indication appears to be
incorrect.
Reference pressure transducer(s)
(RPTs) are inoperable or out of
calibration.
Use [P&T] to view pressure indications.
Recalibrate RPTs if necessary. 3.4.5, 5.2
© 1995 - 2007 DH Instruments, a Fluke Company
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6. TROUBLESHOOTING
SYMPTOM
PROBABLE CAUSE
SOLUTION
Flow indication appears to be
incorrect.
The gas selected is not the gas flowing
through the molbloc.
Select the correct gas. 3.4.2
Flow indication appears to be
incorrect while using molbloc-S to
measure air flow
Incorrect humidity ratio is being used.
Reselect Air as the test gas and make sure
the humidity ratio W is entered properly. W
should be zero for dry air and should be
calculated from ambient conditions when
measuring ambient air. 3.4.2.2.
Flow indication appears to be
incorrect.
The gas selected is the gas flowing
through the molbloc but the molbloc
has not been calibrated for that gas.
Verify that the molbloc has calibration
coefficients for the flowing gas, have the
molbloc calibrated for the flowing gas if
necessary or accept higher measurement
uncertainty in the flow measurements. 3.5.1,
1.2.5
Flow indication appears to be
incorrect.
Gas flowing through molbloc is not
pure.
Check purity rating of gas used; purge
molbox/molbloc if flowing gas was just
changed. If gas is a known mix, use the flow
adder and multiplier to correct for the mix.
3.4.4.2, 3.5.3
Flow indication appears to be
incorrect.
The molbloc is not being used at the
correct pressure for its pressure
dependent calibration type.
Check molbloc Calibration Report for
pressure dependent calibration type and
check operating pressure. 1.2.5, 3.2.5
Flow indication appears to be
incorrect.
molbox1 pressure and/or Reynolds
numbers are outside of limits.
Observe pressure and Reynolds numbers
and adjust pressure/flow to be inside of
limits. 1.2.5, 3.4.5
Flow indication appears to be
incorrect.
Flow through molbloc is in wrong
direction.
Check that flow through molbloc is in
direction of arrow on molbloc. Switch if
necessary.
Flow indication appears to be
incorrect.
Leak in pressure lines from molbloc to
molbox1.
Check lines for leaks and correct if
necessary. 3.4.4.3
Flow indication appears to be
incorrect.
A flow adder or multiplier has been
incorrectly or inadvertently applied.
Check and correct if necessary. 3.5.3
Flow indication appears to be
incorrect.
molbloc calibration has changed due to
contamination.
Check molbloc for contamination. Contact
your DHI Authorized Service Provider if liquid
or particulate contamination is detected. 7.4
Flow indication appears to be
incorrect by a constant offset
amount.
molbox1 needs to be correctly “zeroed”
(tared) at the current operating
pressure.
Tare molbox1. Be sure to tare upstream if
the upstream pressure is constant and
downstream if the downstream pressure is
constant. 3.4.4.1
Flow indication appears to be
incorrect and molbloc is upstream
and reading high.
Leak downstream of molbloc.
Check for and correct leak if present.
Consider using molbox1 SYSTEM LEAK
CHECK function. 3..4.3
Flow indication appears to be
incorrect and flow rate is less than
50 sccm.
Flow in system is not in steady state;
too much volume between molbloc and
test; unstable pressure on molbloc.
Be sure flow is stable before reading, reduce
dead volumes, install precision regulator,
consider using DHI low flow molstic.
Flow indication appears to be
incorrect and flow unit is a
volumetrically based mass flow
unit (sccm, scfh, etc.).
Reference temperature or
compressibility consideration in
volumetrically based units is
inconsistent.
Set units correctly for consistency between
values being compared. Be sure to select a
unit starting in “u” for volumetrically based
mass flow units if reference temperature is
not 0 °C. 3.4.3, 3.4.3.3
Unable to make molbloc-S flow
measurements over full expected
flow range
MFC or flow control valve is connected
dowsntream of molbloc-S
Valve or regulator used to control flow
through molbloc-S must always be upstream
of the molbloc-S. When operating an MFC
with molbloc-S, the MFC must always be
upstream.
Unable to make molbloc-S flow
measurements over full expected
flow range
molbloc-S back pressure too high
The downstream pressure on molbloc-S must
always be significantly lower than the
upstream pressure to maintain critical flow.
When upstream pressure is reduced, the
back pressure ratio may become too high to
make valid flow measurements. 3.1.5
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SYMPTOM
PROBABLE CAUSE
SOLUTION
Unable to make molbloc-S flow
measurements over full expected
flow ranges.
Flow units use reference temperature
other than 0° C.
The molbloc-S flow range tables display flow
ranges expressed in slm @ 0° C. If you use
volumetrically based flow units with another
reference temperature, the minimum usable
flow value may be increased by up to 9% for
a given molbloc-S downstream pressure.
1.2.5.2.1, 3.4.3.3, tables 4 to 14
Unable to reach molbloc-S
maximum flow
Pressure regulator supplying molbloc-S
set too low.
If you are controlling flow with a control valve
downstream of a fixed pressure regulator,
you must have sufficient pressure supply
pressure to reach the maximum desired
molbloc-S flow. Be sure not to exceed
molbox1 maximum operating pressure. 1.2.5,
2.3.4
Flow indication appears to be
incorrect and flow unit is a volume
(actual) flow unit (ccm, cfh, etc.).
Volume flow pressure and/or
temperature is/are incorrect.
Set more accurate values for volume flow
pressure and/or temperature. 3.4.3.1, 3.4.3.4
Flow indication appears to be
incorrect and there is a K following
the flow unit on the display.
A K factor is being applied incorrectly or
inadvertently.
Turn off or correct K factor. 3.4.1
Flow indication appears to be
incorrect and you are using
AVERAGING function.
Averaging period is wrong and does not
correspond to reading period of the
device you are comparing with.
Adjust averaging period and/or be sure to
synchronize averaging period of the molbox1
and the device you are comparing to. 3.4.6.2
Flow indication is negative.
Flow in your system is reverse from
what you expect; molbloc upstream and
downstream pressure lines are
switched.
Check system and correct flow; check
pressure lines and switch if necessary.
Pressure transducer (RPT)
indications are out of range.
Incorrect RPT calibration coefficients;
RPT(s) has (have) been overpressured.
Correct calibration coefficients; have
transducers replaced if damaged. 5.2
molbloc-S Tare does not execute
as expected
Expectation of tare function operation is
incorrect for molbloc-S.
Normal molbox1 operation. The molbloc-S
tare function has a different purpose and
method of operation from molbloc-L tare and
does not require saving a fixed tare value.
3.4.4.1.2
Cannot tare molbox due to
excessive tare value.
One or several RPTs are defective;
RPT calibration is bad; there is a leak
inside molbox1 causing a differential
pressure.
Check performance of RPTs; check
calibration of RPTs; leak check molbox1. 5.2
Leak check does not indicate
pass/fail in molbloc-S operation.
Improper expectation for molbloc-S
leak check..
Normal molbox1 operation. molbloc-S
system leak check function in molbox1 does
not have pass/fail criteria assigned as
molbloc-L leak check does. 3.4.4.3
Measured pressure display has
too much/not enough resolution.
Resolution setting needs to be
changed.
Use [RES] to change resolution setting. 3.4.9
Flow rate is changing but display
of flow is not and the bottom right
hand corner of the display is a
numerical countdown followed by
<avg>.
AVERAGE DISPLAY function is ON
and pressure display is updating only
with the average value at the end of
each averaging cycle.
Go to a DISPLAY function other than
AVERAGE or press [+/-] to get the
instantaneous value AVERAGE DISPLAY.
3.4.6.2
Current flow through the molbloc is
zero but reading is not zero in
molbloc-L operation.
Need to run TARE function to zero
molbox1 RPTs.
Run TARE. 3.4.4.1.1
Poor flow measurement
characterized by instability and
sudden small jumps in flow rate.
The molbox1 pneumatic circuit is
contaminated with liquids.
Purge and clean molbox1 and associated
pneumatic systems. Contact your DHI
Authorized Service Provider. 7.4
Grossly inaccurate flow
measurements and little or no
response to pressure or flow
changes.
RPT(s) destroyed by overpressure.
View pressure readings using [P&T]. If
readings are grossly inaccurate and don’t
respond to pressure changes, contact your
DHI Authorized Service Provider. 3.4.5,
3.1.4, 5.2, 7.4
Apparent inaccurate pressure
measurement.
Incorrect pressure units.
Set desired pressure units. Consider
reference temperature if unit is inWa. 3.5.8
© 1995 - 2007 DH Instruments, a Fluke Company
Page 152
6. TROUBLESHOOTING
SYMPTOM
PROBABLE CAUSE
SOLUTION
Apparent inaccurate pressure or
flow measurement.
Reference pressure transducer (RPT)
calibration coefficients have been
altered or lost and pressure
measurements are incorrect.
Check and correct calibration coefficients if
needed. 5.2
MFC connected to molbox1
doesn’t appear to be responding.
MFC control option is not implemented
on this molbox1.
Check whether molbox1 MFC control option
was ordered and installed.
MFC connected to molbox1
doesn’t appear to be responding.
The MFC control function is not active
(OFF).
Activate MFC control function by selecting a
channel other than zero. 3.4.8
MFC connected to molbox1
doesn’t appear to be responding
correctly.
molbox1 to MFC control cable is not
connected or connected incorrectly.
Check MFC cable connection and MFC cable
configuration. 7.3
MFC value and/or molbox1 flow
values appear incorrect.
MFC profile does not correspond to
MFC in use.
Check MFC profile and create and/or select
correct one. 3.4.8.2, 3.5.5
MFC seems to be adjusting to set
the requested flow value as read
by the molbox.
MFC regulation mode is ON.
Operation is normal. Turn MFC regulation
mode OFF. 3.5.6
MFC value and/or molbox1 flow
values appear incorrect.
Incorrect or inadvertent use of K factor
and/or gas selection.
Check K factor and gas selection and correct
if necessary. 3.4.1, 3.4.2
[ENTER] is not going to MFC set
point screen. Cannot get to MFC
set point entry.
The MFC control option is not
implemented on this molbox or the
current DISPLAY mode does not
support MFC set point entry.
Check whether molbox1 MFC control option
was ordered and installed. If MFC control
option is present, use [DISPLAY] to set
DISPLAY mode to RATE, UNIT or CLEAN.
3.4.6
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© 1995 - 2007 DH Instruments, a Fluke Company
MOLBOX1™ OPERATION AND MAINTENANCE MANUAL
NOTES
© 1995 - 2007 DH Instruments, a Fluke Company
Page 154
7. APPENDIX
7.
APPENDIX
7.1
CONVERSION OF NUMERICAL VALUES
molbox1 performs all internal calculations in SI units. Numerical values input or output in other units are
converted to SI immediately after entry and back to other units just before output as needed.
The tables below provide the conversion coefficients used by molbox1 to convert numerical values
expressed in SI units to corresponding values expressed in other units.
7.1.1
PRESSURE
Table 35. Pressure Unit Conversions
TO CONVERT FROM PA TO
Pa
Pascal
1.0
Mbar
Millibar
1.0 E-02
KPa
kilo Pascal
1.0 E-03
Bar
Bar
1.0 E-05
mmWa @ 4 °C
Millimeter of water
1.019716 E-01
mmHg @ 0 °C
Millimeter of mercury
7.50063 E-03
Psi
pound per square inch
1.450377 E-04
Psf
pound per square foot
1.007206 E-06
inWa @ 4 °C
inch of water
4.014649 E-03
inWa @ 20 °C
inch of water
4.021732 E-03
inWa @ 60 °F
inch of water
4.018429 E-03
inHg @ 0 °C
inch of mercury
2.953 E-04
Kilogram force per centimeter square
1.019716 E-05
User
User defined coefficient
kcm
2
User
7.1.2
MULTIPLY BY
TEMPERATURE
Table 36. Temperature Unit Conversion
TO CONVERT FROM °C TO
MULTIPLY BY
°F
9/5 and add 32
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MOLBOX1™ OPERATION AND MAINTENANCE MANUAL
7.1.3 FLOW
Table 37. Conversions from kg/s
to sccm at 0 °C for Various Gases
TO CONVERT
FROM KG/S TO SCCM AT 0 °C
Air (Air)
MULTIPLY
BY
4.64109 E+07
Argon (Ar)
3.36398 E+07
Butane (C4H10)
2.22112 E+07
Carbon Dioxide (CO2)
3.03490 E+07
Carbon Monoxide (CO)
4.79862 E+07
Carbon Tetrafluoride (CF4)
1.52386 E+07
Ethane (C2H6)
4.42602 E+07
Ethylene (C2H4)
4.75813 E+07
Fluoroform (CHF3)
1.90128 E+07
Helium (He)
3.36210 E+08
Hexafluoroethane (C2F6)
9.60432 E+06
Hydrogen (H2)
6.67483 E+08
Methane (CH4)
8.36354 E+07
Nitrogen (N2)
4.79808 E+07
Nitrous Oxide (N2O)
3.03321 E+07
Oxygen (O2)
4.19903 E+07
Propane (C3H8)
2.98516 E+07
Sulfur Hexafluoride (SF6)
9.06602 E+06
Xenon (Xe)
1.01710 E+07
Table 38. Conversions from sccm at 0 °C
to Other Volumetrically Based Flow Units
TO CONVERT
FROM SCCM AT 0 °C
TO OTHER
VOLUMETRICALLY BASED
UNITS
© 1995 - 2007 DH Instruments, a Fluke Company
MULTIPLY
BY
Slm
1.0 E-03
Slh
6.0 E-02
Scfm
3.53147 E-05
Scfh
2.11888 E-03
Sm3m
1.0 E-06
Sm3h
6.0 E-05
Page 156
7. APPENDIX
Table 39. Conversions from Volumetrically Based Flow Units
at 0 °C to Corresponding Units at Another Temperature (uxxx)
TO CONVERT VOLUMETRICALLY BASED UNITS
AT 0 °C TO CORRESPONDING UNITS AT
ANOTHER TEMPERATURE, Θ, (UXXX)
MULTIPLY BY
sccm
slm
(TN + θ) ⋅ Ζ (PN ,( TN +θ))
slh
scfm
TN ⋅ Ζ N
scfh
sm3m
Where:
θ=
sm3h
Alternate reference flow temperature [K].
TN = 273.15K
PN = 101325 Pa
Z (PN ,(TN +θ )) ;Z N gas dependent compressibility factors
Table 40. Conversions from kg/s
to mole/s for Various Gases
TO CONVERT KG/SEC TO
MOLE/S
Air (Air)
MULTIPLY
BY
3.45316 E+01
Argon (Ar)
2.50325 E+01
Butane (C4H10)
1.72049 E+01
Carbon Dioxide (CO2)
2.27221 E+01
Carbon Monoxide (CO)
3.57015 E+01
Carbon Tetrafluoride (CF4)
1.13624 E+01
Ethane (C2H6)
3.32568 E+01
Ethylene (C2H4)
3.56455 E+01
Fluoroform (CHF3)
1.42837 E+01
Helium (He)
2.49838 E+02
Hexafluoroethane (C2F6)
7.24533 E+00
Hydrogen (H2)
4.96032 E+02
Methane (CH4)
6.23325 E+01
Nitrogen (N2)
3.56939 E+01
Nitrus Oxide (N2O)
2.27206 E+01
Oxygen (O2)
3.12512 E+01
Propane (C3H8)
2.26778 E+01
Sulfur Hexafluoride (SF6)
6.84697 E+00
Xenon (Xe)
7.61615 E+00
Table 41. Conversion from mole/s to pccm
TO CONVERT MOLE/SEC
TO PCCM
Any Gas
MULTIPLY
BY
1.34483 E+06
The “p” in pccm indicates “perfect” in which a gas compressibility factor of 1 is assumed
for all gases. In early 1996, SEMI, a semiconductor industry group, adopted standard
E12-96 which specified that this definition be used for volumetrically base mass flow units.
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MOLBOX1™ OPERATION AND MAINTENANCE MANUAL
Table 42. Conversion from sccm at 0 °C
to Volume Flow Units at Another Pressure and Temperature
TO CONVERT FROM A VOLUMETRIC MASS
FLOW UNIT TO THE EQUIVALENT VOLUME
FLOW UNIT AT TEMPERATURE θ AND PUSER
MULTIPLY BY
sccm to ccm
slm to lm
(TN + θ) ⋅ Ζ (PN ,( TN +θ))
slh to lhs
cfm to cfm
TN ⋅ Ζ N
scfh to cfh
sm3m to m3m
sm3h to m3h
Where:
TN = 27315
. K
Puser = user pressure [kPa]
θ = user temperature [K]
PN = 101.325 kPa
z(Puser ,( TN +θ )) ; zN = gas dependent compressibility factors
7.2
VALVE DRIVERS
The molbox1 drivers option provides eight open collector drivers for operating external valves, solenoids,
indicators, etc. When operating from the setup-driver screen, pressing enter will allow the operating
mode of the drivers to be set. The two modes of operation are Momentary and Toggle. A momentary
driver will be activated while the corresponding driver number on the keyboard is being pressed. In
toggle mode the driver state will toggle each time the corresponding key is pressed.
Each output can sink 500 mA at 12 V. However, the total output of all the activated drivers cannot
exceed 1 Amp. Therefore, if multiple drivers are being activated please refer to Table 43 as a guide.
Table 43. Driver/Max Current Per Output
© 1995 - 2007 DH Instruments, a Fluke Company
# OF ACTIVE
DRIVERS
MAX CURRENT
PER OUTPUT
1
500 mA
2
400 mA
3
275 mA
4
200 mA
5
160 mA
6
135 mA
7
120 mA
8
100 mA
Page 158
7. APPENDIX
Table 44 and Figure 15 should be used as reference when building a cable to utilize the drivers port.
Table 44. External Drivers
PIN
DESCRIPTION
A
D1
C
D2
Driver #1 (Open Collector)
Driver #2 (Open Collector)
E
D3
Driver #3 (Open Collector)
G
D4
Driver #4 (Open Collector)
M
D5
Driver #5 (Open Collector)
J
D6
Driver #6 (Open Collector)
K
D7
Driver #7 (Open Collector)
L
D8
Driver #8 (Open Collector)
B
Drivers (+12 V)
D
Drivers (+12 V)
F
Drivers (+12 V)
H
Drivers (+12 V)
Figure 15. Cable Driver Ports
Page 159
© 1995 - 2007 DH Instruments, a Fluke Company
MOLBOX1™ OPERATION AND MAINTENANCE MANUAL
7.3
MFC CONTROL FUNCTION
7.3.1
MFC CONNECTOR
Table 45 should be used to correctly build the interfacing cable required to connect the
molbox1 to an MFC.
Table 45. Interface Cable Building Instructions
© 1995 - 2007 DH Instruments, a Fluke Company
MOLBOX1 MFC
INTERFACE
CONNECTOR (25 PIN
DSUB) PIN NO.
SIGNAL DESCRIPTION
1
Case Ground
2
Supply Common
3
MFC Output (+)
4
+15 Volts
5
N/C
6
N/C
7
Set Point Sense (-)
8
N/C
9
N/C
10
N/C
11
Valve Test
12
Current MFC Output (+)
13
Current MFC Set (+)
14
MFC Setpoint (+)
15
MFC Setpoint (-)
16
MFC Output (-)
17
Valve Test Common
18
N/C
19
-15 Volts
20
Set Point Sense (+)
21
N/C
22
N/C
23
N/C
24
RS485 TXRX+
25
RS485 TXRX-
Page 160
7. APPENDIX
7.3.1.1
DETAILED SIGNAL DESCRIPTIONS
•
+15 Volts: This is the positive 15 Volt supply for the MFC.
•
-15 Volts: The negative 15 Volt supply for the MFC.
•
Current MFC Output (+): This signal is only used for current controlled
MFCs. This is the 4-20 mA signal that represents the MFC’s output.
•
Current MFC Set (+): This signal is only used for current controlled MFCs.
This is the 4-20 mA signal that defines the desired setpoint for the MFC. It is
frequently referred to as the MFC control signal or the MFC setpoint.
•
MFC Output (+): This is the positive 0 to 5 Volt signal that represents the
MFC’s output. It is commonly referred to as “output” or “signal output”.
•
MFC Output (-): This is the ground reference for the MFC output signal. It
is frequently referred to as “Signal Common”, or “Common”.
•
MFC Setpoint (+): This is the desired setpoint for the MFC. It is the signal
that controls the amount of gas that the MFC will flow. It is generally a 0 to 5
Volt signal where 0 Volt signal causes the valve to close (zero flow) and 5
Volt signal cause the valve to open fully resulting in full scale flow. This
signal is commonly referred to as “MFC set point”, “MFC set voltage”, “MFC
command”, or “MFC control”.
•
MFC Setpoint (-): This is the ground reference for the MFC Setpoint signal.
It is frequently referred to as “Signal Common”, or “Common”.
•
N/C: This abbreviation stands for no connection. There are no signals on
the lines marked N/C.
•
RS485 TXRX+: This is the RS485 TXRX+ signal. It is used to communicate
with digital MFCs using the RS485 communications protocol. The RS485
signals are also available on the phone jack style connector on the molbox1.
•
RS485 TXRX-: This is the RS485 TXRX+ signal. It is used to communicate
with digital MFCs using the RS485 communications protocol. The RS485
signals are also available on the phone jack style connector on the molbox1.
•
Set Point Sense (+): This signal is used by the molbox1 to detect loss along
the MFC cable. It represents the positive MFC set point as seen by the
MFC. This line should be connected to the same point as the MFC Setpoint
(+) line at the MFC side of the cable.
•
Set Point Sense (-): This is the ground reference for the MFC Setpoint
sense. It should be connected to the same point as the MFC setpoint (-) line.
•
Supply Common: This is the ground line for the MFC’s power connection.
It is frequently referred to as “Power Common”, “Supply Common”, or just “Common”.
•
Valve Test: This optional connection is used to read the valve test point
signal coming from the MFC. If this signal is available at the MFC connector,
it allows the user to read the internal voltage delivered to the MFC valve.
•
Valve Test Common: This is the reference for the valve test signal. It may
be connected to a common line or the –15V line of the MFC, depending on
the instructions of the MFC manufacturer for valve voltage measurement.
7.3.1.2
POPULAR CONFIGURATIONS
The following configuration can be used with most card edge style MFCs.
Any differences tend to relate to the handling of the ground (common) lines (pins 2,
B and C). Most cable problems can be resolved by either shorting pins B and C
Page 161
© 1995 - 2007 DH Instruments, a Fluke Company
MOLBOX1™ OPERATION AND MAINTENANCE MANUAL
or by swapping the signals connected to pin 2 of the card edge connector with
the signals connected to pin B of the card edge connector. The configuration
below should work with the following MFCs.
•
Millipore (Tylan) model FC260, 261, 262, FM 360, 361, 362
•
Qualiflow AFC 260, 261, 202, 360, 361, 302
•
Aera 2600, 2610, 2620, 3600, 3610, 3620
•
PFD 501
•
Porter 201
•
Unit Instruments models UFC 1000,1020, 1100,1200, 1400, 1500
Table 46. Common MFC Connector Pin Out
MOLBOX1 MFC
INTERFACE
CONNECTOR
(25 PIN DSUB)
PIN NO.
SIGNAL
DESCRIPTION
MFC CARD EDGE
CONNECTOR PIN
NOS.
1
Case Ground
1 (A1)
2
Supply Common
2 (A2)
3
MFC Output (+)
3 (A3)
4
+15 Volts
4 (A4)
7
Set Point Sense (-)
B (B2)
11
Valve Test
D (Optional) (B4)
14
MFC Setpoint (+)
A (B1)
15
MFC Setpoint (-)
B (B2)
16
MFC Output (-)
C (B3)
17
Valve Test Common
F (Optional) (B6)
19
-15 Volts
F (B6)
20
Set Point Sense (+)
A (B1)
The following configuration can be used with:
•
Brooks model 5850E, and 5851E
Table 47. Brooks MFC Connector Pin Out
MOLBOX1
MFC INTERFACE
CONNECTOR
(25 PIN DSUB)
PIN NO.
© 1995 - 2007 DH Instruments, a Fluke Company
SIGNAL
DESCRIPTION
MFC CARD
EDGE
CONNECTOR
PIN NOS.
MFC 15 PIN DSUB
CONNECTOR PIN
NOS.
1
Case Ground
1 (A1)
14
2
Supply Common
C (B3)
9
3
MFC Output (+)
3 (A3)
2
4
+15 Volts
4 (A4)
5
7
Set Point Sense (-)
2 (A2)
10
11
Valve Test
D (Optional) (B4)
7 (Optional)
14
MFC Setpoint (+)
A (B1)
8
15
MFC Setpoint (-)
2 (A2)
10
16
MFC Output (-)
B (B2)
10
17
Valve Test Common
F (Optional) (B6)
10 (Optional)
19
-15 Volts
F (B6)
6
20
Set Point Sense (+)
A (B1)
8
Page 162
7. APPENDIX
7.4
WARRANTY STATEMENT
Except to the extent limited or otherwise provided herein, DH Instruments, a Fluke Company (DHI)
warrants for one year from purchase, each new product sold by it or one of its authorized distributors,
only against defects in workmanship and/or materials under normal service and use. Products which
have been changed or altered in any manner from their original design, or which are improperly or
defectively installed, serviced or used are not covered by this warranty.
DHI and any of its authorized service providers’ obligations with respect to this warranty are limited to the repair
or replacement of defective products after their inspection and verification of such defects. All products to
be considered for repair or replacement are to be returned to DHI, or its authorized service provider,
freight prepaid, after receiving authorization from DHI or its authorized service provider. The buyer assumes
all liability vis-à-vis third parties in respect of its acts or omissions involving use of the products. In no event
shall DHI be liable to purchaser for any unforeseeable or indirect damage, it being expressly stated that,
for the purpose of this warranty, such indirect damage includes, but is not limited to, loss of production,
profits, revenue, or goodwill, even if DHI has been advised of the possibility thereof, and regardless of
whether such products are used individually or as components in other products.
Items returned to DHI under warranty claim but determined to not have a defect covered under warranty
or to not have a defect at all are subject to an evaluation and shipping charge as well as applicable repair
and/or calibration costs.
The provisions of this warranty and limitation may not be modified in any respect except in writing signed
by a duly authorized officer of DHI.
The above warranty and the obligations and liability of DHI and its Authorized Service Providers exclude
any other warranties or liabilities of any kind.
Table 48. DHI Authorized Service Providers
DH INSTRUMENTS, A FLUKE COMPANY
AUTHORIZED SERVICE PROVIDERS
COMPANY
TELEPHONE,
FAX & EMAIL
ADDRESS
NORMAL SUPPORT
REGION
DH Instruments, a Fluke
Company
4765 East Beautiful Lane
Phoenix AZ 85044-5318
USA
Tel 602.431.9100
Fax 602.431.9559
[email protected]
Worldwide
Minerva Meettechniek B.V.
Chrysantstraat 1
3812 WX Amersfoort
the NETHERLANDS
Tel (+31) 33.46.22.000
Fax (+31) 33.46.22.218
[email protected]
European Union
Nippon CalService, Inc.
2-9-1 Sengen, Tsukuba-Shi
Ibaraki Prefecture 305
JAPAN
Tel 0298-55-8778
Fax 0298-55-8700
[email protected]
Japan/Asia
DH Products Technical
Service Division
National Institute of Metrology
Heat Division
Pressure & Vacuum Lab
NO. 18, Bei San Huan Donglu
Beijing 100013
PR CHINA
Tel 010-64291994 ext 5
Tel 010-64218637 ext 5
Fax 010-64218703
[email protected]
Peoples Republic of
China
Page 163
© 1995 - 2007 DH Instruments, a Fluke Company
MOLBOX1™ OPERATION AND MAINTENANCE MANUAL
NOTES
© 1995 - 2007 DH Instruments, a Fluke Company
Page 164
8. GLOSSARY
8.
GLOSSARY
Absolute
As in “absolute pressure”. Pressure expressed relative to vacuum.
BPR
Back Pressure Ratio. The ratio of the downstream pressure to the upstream pressure on a
molbloc-S critical flow based molbloc element. The BPR is used to determine whether
Critical Flow conditions exist so that molbloc-S flow measurements are valid.
Critical flow
Also known as “sonic flow”. Flow regime where the speed of gas is accelerated to a velocity
equal to the speed of sound under current conditions and the flow rate can be predicted by
measurement of the upstream pressure at the flow restriction (nozzle), the gas pressure and
temperature conditions and the gas properties.
Clean
A DISPLAY function in which the second line of the display is blank (clean).
Deviation
A DISPLAY function in which the deviation from a target flow value is calculated and
displayed. The value of the difference between the target and the current flow reading.
Differential
As in “differential pressure”. Pressure expressed relative to a value other than vacuum or
atmospheric pressure (see absolute and gauge). Frequently refers to the pressure drop
across the molbloc.
Downstream
Location of point A relative to point B in a flow system in which point A is at a different
location in the direction of the flow. For example, the downstream molbloc pressure port is
downstream relative to the upstream pressure port because it is at a different location from
the upstream port in the direction of the flow.
DUT
Device Under Test. The device being tested or calibrated.
FA (Flow Adder)
Flow adder. A value that is added to the measured flow to offset the measured flow value.
FM (Flow Multiplier)
Flow multiplier. A value by which the measured flow is multiplied to change the slope of the
measured flow.
Freeze
A DISPLAY function in which the current flow reading can be captured and displayed by
pressing [ENTER].
Full Mod Calibration
A molbloc calibration option which is valid over a range of operating pressure.
FS
Abbreviation of "full scale". The full scale value is the maximum value or the span of a
measurement range. Limits and specifications are often expressed as % FS.
Gauge
As in “gauge pressure”. Pressure expressed relative to atmospheric pressure.
Head
The differential pressure developed by differences in height between two points within a fluid
medium.
Hi/Lo
A DISPLAY function in which the highest and lowest flow observed since hi/lo reset are
recorded and displayed.
K Factor
A factor representing the relationship between the process gas and a surrogate gas for a DUT.
Operating Pressure
The average pressure at which the molbloc is operated (average of upstream and
downstream pressure) or, if the molbloc pressure is held constant by an upstream or
downstream regulator, the value of the constant pressure.
PA (Pressure Adder)
Pressure adder, used in calibration adjustment to offset an RPT.
Perfect Mass Flow Units
Volumetrically based mass flow units of measure that assume ideal gas behavior for all
gases (compressibility factor of 1).
PM (Pressure Multiplier)
Pressure multiplier, used in calibration to adjust span of an RPT.
Pmax!
The overpressure limit of an RPT. If the pressure measured exceeds (Pmax!) an
overpressure condition occurs.
Process Gas
The gas for which a device under test (DUT) is to be characterized or calibrated. The gas
that will actually flow in the DUT when it is used in a process.
PRT
Platinum Resistance Thermometer. The element used in molblocs to measure temperature.
Psia
Pressure unit “pounds per square inch absolute”. Pressure expressed relative to vacuum.
Psig
Pressure unit “pounds per square inch gauge”. Pressure expressed relative to atmospheric
pressure.
Rate
A DISPLAY function in which the current rate of change of the flow in flow units/second is
displayed. A measure of stability of the flow. See also Stability Limit.
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© 1995 - 2007 DH Instruments, a Fluke Company
MOLBOX1™ OPERATION AND MAINTENANCE MANUAL
Ready/Not Ready
Indication of when flow is stable within the stability limit and below the flow Reynolds number
limit. See also Stability Limit.
Reynolds Number
A ratio of the inertia forces to the viscous forces in a flowing fluid. This dimensionless
number, which is dependent on fluid viscosity, density, velocity and length of the flow field, is
often used to predict a boundary point between laminar and turbulent flow regimes.
RPT
Reference Pressure Transducer. The pressure transducers used in molbox1 are referred to
as RPTs.
Single P Calibration
A molbloc calibration option for gases other than N2 which is valid at a single specified
operating pressure.
Stability Limit
A limit expressed in units of flow per second (e.g., sccm/second). The stability limit is used
as the Ready/Not Ready criterion Ready (<*>) if rate is less than stability limit, Not Ready
(<↑> or <↓>) if rate is greater than stability limit. See also Rate.
Surrogate Gas
A gas whose behavior, from the standpoint of a device under test, is similar to the process
gas for which the device is to be characterized and used. A surrogate gas is often used in
calibration and testing when the process gas cannot be used for safety or cost reasons.
Target
The value from which deviations are measured in the DEVIATION DISPLAY function.
Test Gas
The gas flowing through the molbloc that is being used to run the test or calibration.
The test gas, from the standpoint of the device under test, could be a surrogate gas or
the process gas.
Totalize
A DISPLAY function in which the total mass or volume flowed over a period of time is
accumulated.
Upstream
Location of point A relative to point B in a flow system in which point A is at a different
location in the opposite direction of the flow. For example, the upstream molbloc pressure
port is upstream relative to the downstream pressure port because it is at a different location
from the downstream port in the opposite direction of the flow.
User Level
Level of security that can be set to prevent access to certain molbox1 functions.
User Mass Flow Units
Volumetrically based mass flow units of measure with a user set reference temperature.
Venturi nozzle
A flow orifice using a specific shape characterized by a convergent and divergent section,
used to define flow measurements by measurement of flow conditions and gas properties.
A critical flow Venturi nozzle is a Venturi nozzle used to define flows within the Critical
flow regime.
Volume Flow Pressure
The absolute pressure of the flowing gas at the device under test for volume flow units
of measure.
Volume Flow Temperature
The temperature of the flowing gas at the device under test for volume flow units of measure.
Volume Flow Units
Units of measure of volume (sometimes called “actual”) flow.
© 1995 - 2007 DH Instruments, a Fluke Company
Page 166