Model 450 Gaussmeter User`s Manual, 2002

Model 450 Gaussmeter User`s Manual, 2002
User’s Manual
Model 450
Gaussmeter
Lake Shore Cryotronics, Inc.
575 McCorkle Boulevard
Westerville, Ohio 43082-8888 USA
E-Mail Addresses:
[email protected]
[email protected]
Visit Our Website:
www.lakeshore.com
Fax: (614) 891-1392
Telephone: (614) 891-2243
Methods and apparatus disclosed and described herein have been developed solely on company funds of Lake Shore Cryotronics, Inc.
No government or other contractual support or relationship whatsoever has existed which in any way affects or mitigates proprietary
rights of Lake Shore Cryotronics, Inc. in these developments. Methods and apparatus disclosed herein may be subject to U.S. Patents
existing or applied for. Lake Shore Cryotronics, Inc. reserves the right to add, improve, modify, or withdraw functions, design
modifications, or products at any time without notice. Lake Shore shall not be liable for errors contained herein or for incidental or
consequential damages in connection with furnishing, performance, or use of this material.
Rev. 1.5
P/N 119-005
12 August 2002
Lake Shore Model 450 Gaussmeter User’s Manual
LIMITED WARRANTY
Lake Shore Cryotronics, Inc. (henceforth Lake Shore), the manufacturer, warrants this product to be free from defects in material and
workmanship for a period of 12 months from the date of shipment. During the warranty period, under authorized return of instruments or
component parts to Lake Shore freight prepaid, the company will repair, or at its option replace, any part found to be defective in material
or workmanship, without charge to the Owner for parts, service labor, or associated customary shipping cost. Replacement or repaired
parts will be warranted for only the unexpired portion of the original warranty or 90 days (whichever is greater).
All products are tested and calibrated to published specifications prior to shipment. Calibration Certifications are offered for 12-month
periods only. Where such documentation must be updated, a re-certification service is offered by Lake Shore at a reasonable cost.
LIMITATION OF WARRANTY
This warranty is limited to Lake Shore products purchased and installed in the United States, or Internationally through our approved
distribution agents. This same protection will extend to any subsequent owner during the warranty period. It does not apply to damage
resulting from improper or inadequate maintenance, unauthorized modification or misuse, or operation outside of the environmental
specifications. It does not apply to damage caused by accident, misuse, fire, flood, or acts of God, or from failure to properly install,
operate, or maintain the product in accordance with the printed instruction provided.
This warranty is in lieu of any other warranties, expressed or implied, including merchantability or fitness for a particular purpose, which
are expressly excluded. The owner agrees that Lake Shore’s liability with respect to this product shall be set forth in this warranty, and
incidental or consequential damages are expressly excluded.
CERTIFICATION
Lake Shore certifies that this product has been inspected and tested in accordance with its published specifications and that this product
met its published specifications at the time of shipment. The accuracy and calibration of this product at the time of shipment are traceable
to the United States National Institute of Standards and Technology (NIST); formerly known as the National Bureau of Standards (NBS).
FIRMWARE LIMITATIONS
Lake Shore has worked to ensure that the Model 450 firmware is as free of errors as possible, and that the results you obtain from the
instrument are accurate and reliable. However, as with any computer-based software, the possibility of errors exists.
In any important research, when using any laboratory equipment, results should be carefully examined and rechecked before final
conclusions are drawn. Neither Lake Shore nor anyone else involved in the creation or production of this firmware can pay for loss of
time, inconvenience, loss of use of the product, or property damage caused by this product or its failure to work, or any other incidental or
consequential damages. Use of our product implies you understand the Lake Shore license agreement and statement of limited warranty.
FIRMWARE LICENSE AGREEMENT
The firmware in this instrument is protected by United States copyright law and international treaty provisions. To maintain the warranty,
the code contained in the firmware must not be modified. Any changes made to the code is at the user’s risk. Lake Shore will assume no
responsibility for damage or errors incurred as result of any changes made to the firmware.
Under the terms of this agreement you may only use the Model 450 firmware as physically installed in the instrument. Archival copies are
strictly forbidden. You may not decompile, disassemble, or reverse engineer the firmware. If you suspect there are problems with the
firmware, return the instrument to Lake Shore for repair under the terms of the Limited Warranty specified above. Any unauthorized
duplication or use of the Model 450 firmware in whole or in part, in print, or in any other storage and retrieval system is forbidden.
SOFTWARE LICENSE AGREEMENT
This software is protected by United States copyright law and international treaty provisions. Lake Shore provides this software package
and grants you (the user of the software) a non-exclusive and non-transferable right to use this software. Unless as provided in this
Agreement, any attempt to sublicense, lease, rent, assign, or transfer this license or this software is void. To maintain software warranty,
the source code must not be modified. Any changes made to the HALLCAL.EXE source code is at the user’s risk. Lake Shore assumes
no responsibility for damage or errors incurred as result of any changes made to the source code.
This agreement allows you to use the HALLCAL.EXE Software on any one computer system. One archival floppy disk is permitted. Any
unauthorized duplication or use of the software in whole or in part, in print, or in any other storage and retrieval system is forbidden.
Lake Shore works to ensure the HALLCAL.EXE Software is as free of errors as possible, and that the results you obtain from the system
are accurate and reliable. However, understand that with any computer software the possibility of software errors exist. In any important
research, as when using any laboratory equipment, results should be carefully examined and rechecked before final conclusions are
drawn. Neither Lake Shore nor anyone else involved in the creation or production of this software can pay for loss of time, inconvenience,
lost of use of the product, or property damage caused by this product or its failure to work, or any other incidental or consequential
damages. Use of our product implies that you understand the Lake Shore license agreement and statement of limited warranty.
TRADEMARK ACKNOWLEDGMENT
Many manufacturers and sellers claim designations used to distinguish their products as trademarks. Where those designations appear
in this manual and Lake Shore was aware of a trademark claim, they appear with initial capital letters and the ™ or ® symbol.
CalCurve™, Carbon-Glass™, Cernox™, Duo-Twist™, Quad-Lead™, Quad-Twist™,
and SoftCal™ are trademarks of Lake Shore Cryotronics, Inc.
MS-DOS® and Windows/95/98/NT® are trademarks of Microsoft Corporation.
NI-488.2™ is a trademark of National Instruments.
PC, XT, AT, and PS-2 are trademarks of IBM.
Copyright © 1992 – 2000, and 2002 by Lake Shore Cryotronics, Inc. All rights reserved. No portion of this manual may be
reproduced, stored in a retrieval system, or transmitted, in any form or by any means, electronic, mechanical,
photocopying, recording, or otherwise, without the express written permission of Lake Shore.
A
Lake Shore Model 450 Gaussmeter User’s Manual
DECLARATION OF CONFORMITY
We:
Lake Shore Cryotronics, Inc.
575 McCorkle Blvd.
Westerville OH 43082-8888 USA
hereby declare that the equipment specified conforms to the following
Directives and Standards:
Application of Council Directives:
Standard to which Conformity is declared:
Model Number:
______________________________
Signature
73/23/EEC
89/336/EEC
EN55022
EN50082-1
EN61010-1
450
_____________________
Date
John M. Swartz
Printed Name
President
Position
B
Lake Shore Model 450 Gaussmeter User’s Manual
Electromagnetic Compatibility (EMC) for the Model 450 Gaussmeter
Electromagnetic Compatibility (EMC) of electronic equipment is a growing concern
worldwide. Emissions of and immunity to electromagnetic interference is now part of the
design and manufacture of most electronics. To qualify for the CE Mark, the Model 450
meets or exceeds the generic requirements of the European EMC Directive 89/336/EEC.
The instrument was tested under normal operating conditions with sensor and interface
cables attached. If the installation and operating instructions in the User’s Manual are
followed, there should be no degradation in EMC performance.
Pay special attention to instrument cabling. Improperly installed cabling may defeat even
the best EMC protection. For the best performance from any precision instrument, follow
the grounding and shielding instructions in the User’s Manual. In addition, the installer of
the Model 450 should consider the following:
C
•
Leave no unused or unterminated cables attached to the instrument.
•
Make cable runs as short and direct as possible.
•
Do not tightly bundle cables that carry different types of signals.
•
Add the clamp-on ferrite filter (Part Number 109-053) included with the connector kit to
the serial interface cable near the instrument rear panel when that interface is used.
Lake Shore Model 450 Gaussmeter User’s Manual
TABLE OF CONTENTS
Chapter/Paragraph
Title
Page
1
INTRODUCTION .................................................................................................................................... 1-1
1.0
General ............................................................................................................................... 1-1
1.1
Model 450 Gaussmeter System Description ...................................................................... 1-2
1.2
Safety Summary.................................................................................................................. 1-5
1.3
Safety Symbols ................................................................................................................... 1-5
2
INSTALLATION ..................................................................................................................................... 2-1
2.0
General ............................................................................................................................... 2-1
2.1
Inspection and Unpacking................................................................................................... 2-1
2.2
Repackaging For Shipment ................................................................................................ 2-1
2.3
Definition of Rear Panel Connections ................................................................................. 2-2
2.4
Line Input Assembly............................................................................................................ 2-3
2.5
Probe Input Connection ...................................................................................................... 2-3
2.6
Corrected and Monitor Analog Outputs .............................................................................. 2-4
2.7
Initial Setup and System Checkout Procedure ................................................................... 2-4
3
OPERATION .......................................................................................................................................... 3-1
3.0
General ............................................................................................................................... 3-1
3.1
Definition of Front Panel Controls ....................................................................................... 3-1
3.1.1
Front Panel Keypad Definitions ....................................................................................... 3-1
3.1.2
Front Panel Display ......................................................................................................... 3-3
3.2
Max Hold and Max Reset.................................................................................................... 3-3
3.3
Zero Probe .......................................................................................................................... 3-3
3.4
Select Range and Auto Range ........................................................................................... 3-4
3.5
AC/DC and Peak/RMS........................................................................................................ 3-5
3.6
Filter .................................................................................................................................... 3-5
3.6.1
Display Filter .................................................................................................................... 3-5
3.6.2
Field and Temperature Compensation ............................................................................ 3-6
3.7
Gauss/Tesla ........................................................................................................................ 3-6
3.8
Relative Set and Relative On/Off ........................................................................................ 3-7
3.9
Alarm Set and Alarm On/Off ............................................................................................... 3-7
3.10
Local and Address .............................................................................................................. 3-9
3.11
Baud .................................................................................................................................... 3-9
3.12
Analog Out .......................................................................................................................... 3-9
3.12.1
Corrected Analog Out .................................................................................................... 3-10
3.12.2
Monitor Analog Out ........................................................................................................ 3-11
3.12.3
Analog Output Control Mode ......................................................................................... 3-11
3.13
Locking and Unlocking the Keyboard ............................................................................... 3-12
3.14
Factory Default Settings.................................................................................................... 3-12
3.15
Probe Considerations........................................................................................................ 3-13
3.15.1
Changing Probes ........................................................................................................... 3-13
3.15.2
Probe Handling .............................................................................................................. 3-13
3.15.3
Probe Operation ............................................................................................................ 3-14
3.15.4
Probe Accuracy Considerations .................................................................................... 3-15
3.16
Fast Data Mode................................................................................................................. 3-16
4
REMOTE OPERATION .......................................................................................................................... 4-1
4.0
General ............................................................................................................................... 4-1
4.1
IEEE-488 Interface.............................................................................................................. 4-1
4.1.1
Model 450 IEEE-488 Interface Settings .......................................................................... 4-1
4.1.2
IEEE-488 Interface Command Structure ......................................................................... 4-2
4.1.2.1
Bus Control Commands ............................................................................................... 4-2
4.1.2.2
Common Commands.................................................................................................... 4-2
4.1.2.3
Interface and Device Specific Commands ................................................................... 4-2
4.1.3
Status Registers............................................................................................................... 4-3
4.1.3.1
Status Byte Register and Service Request Enable Register ....................................... 4-3
i
Lake Shore Model 450 Gaussmeter User’s Manual
TABLE OF CONTENTS (Continued)
Chapter/Paragraph
4.1.3.2
4.1.4
4.1.4.1
4.1.4.2
4.1.5
4.2
4.2.1
4.2.2
4.2.3
4.2.4
4.3
4.3.1
4.3.2
4.3.3
4.3.4
4.3.5
Title
Page
Standard Event Status Register and Standard Event Status Enable Register ............4-3
Example IEEE Setup and Program..................................................................................4-4
GPIB Board Installation.................................................................................................4-4
Running the Example QuickBasic Program..................................................................4-4
Notes on Using the IEEE Interface ..................................................................................4-5
Serial I/O Interface...............................................................................................................4-7
Serial Interface Configuration...........................................................................................4-8
Serial Interface Settings ...................................................................................................4-8
Sample BASIC Serial Interface Program .........................................................................4-8
Notes on Using the Serial Interface .................................................................................4-9
IEEE-488/Serial Interface Command Summary................................................................4-10
Command List Structure.................................................................................................4-10
Common Commands .....................................................................................................4-11
Interface Commands ......................................................................................................4-13
Device Specific Commands ...........................................................................................4-14
Probe Specific Commands.............................................................................................4-22
5
ACCESSORIES AND PROBES .............................................................................................................5-1
5.0
General ................................................................................................................................5-1
5.1
Models .................................................................................................................................5-1
5.2
Accessories .........................................................................................................................5-1
5.3
Lake Shore Standard Probes ..............................................................................................5-3
5.3.1
Probe Selection Criteria ...................................................................................................5-3
5.3.2
Radiation Effects on Gaussmeter Probes ........................................................................5-3
5.3.3
Probe Specifications.........................................................................................................5-4
5.4
Helmholtz Coils....................................................................................................................5-8
5.5
Reference Magnets ...........................................................................................................5-10
6
SERVICE.................................................................................................................................................6-1
6.0
General ................................................................................................................................6-1
6.1
General Maintenance Precautions ......................................................................................6-1
6.2
Electrostatic Discharge........................................................................................................6-1
6.2.1
Identification of Electrostatic Discharge Sensitive Components ......................................6-2
6.2.2
Handling of Electrostatic Discharge Sensitive Components ............................................6-2
6.3
Line Voltage Selection.........................................................................................................6-2
6.4
Fuse Replacement ..............................................................................................................6-3
6.5
Rear Panel Connector Definitions .......................................................................................6-4
6.5.1
IEEE-488 Interface Connector .........................................................................................6-5
6.6
Optional Serial Interface Cable and Adapters .....................................................................6-6
6.7
Operating Software EPROM Replacement .........................................................................6-7
APPENDIX A – GLOSSARY OF TERMINOLOGY ..................................................................................... A-1
APPENDIX B – UNITS FOR MAGNETIC PROPERTIES............................................................................ B-1
APPENDIX C – HALL GENERATORS........................................................................................................ C-1
C1.0
General ............................................................................................................................... C-1
C2.0
Theory of Operation............................................................................................................ C-1
C2.1
Active Area ...................................................................................................................... C-1
C2.2
Orientation ....................................................................................................................... C-2
C2.3
Handling .......................................................................................................................... C-3
C2.4
Polarity............................................................................................................................. C-3
C2.5
Lead Configurations ........................................................................................................ C-3
C3.0
Hall Generator Generic Hookup ......................................................................................... C-3
C4.0
Using a Hall Generator with the Model 450........................................................................ C-4
C5.0
Specifications...................................................................................................................... C-5
C6.0
HALLCAL.EXE Program..................................................................................................... C-8
ii
Lake Shore Model 450 Gaussmeter User’s Manual
LIST OF ILLUSTRATIONS
Figure No.
Title
Page
1-1
Model 450 Gaussmeter Front Panel ................................................................................................ 1-2
2-1
2-2
2-3
Model 450 Rear Panel ..................................................................................................................... 2-1
Line Input Assembly......................................................................................................................... 2-3
Model MCBL-6 User Programmable Cable Accessory.................................................................... 2-4
3-1
3-2
3-3
3-4
3-5
3-6
Model 450 Front Panel..................................................................................................................... 3-1
Front Panel Display Definition.......................................................................................................... 3-3
Display Filter Response Examples .................................................................................................. 3-6
Maximum Flexible Probe Bend Radius.......................................................................................... 3-14
Probe Orientation For Positive Measurement................................................................................ 3-14
Effect Of Angle On Measurements ................................................................................................ 3-15
4-1
4-2
Typical National Instruments GPIB Configuration from IBCONF.EXE ............................................ 4-6
Serial Interface Adapters.................................................................................................................. 4-7
5-1
5-2
5-3
5-4
5-5
5-6
5-7
5-8
5-9
5-10
5-11
5-12
5-13
5-14
5-15
Definition of Lake Shore Transverse Probes ................................................................................... 5-4
Definition of Lake Shore Axial Probes ............................................................................................. 5-5
Definition of Lake Shore Flexible Transverse Probes...................................................................... 5-6
Definition of Lake Shore Gamma Probes™..................................................................................... 5-7
Model MH-2.5 Helmholtz Coil .......................................................................................................... 5-8
Model MH-6 Helmholtz Coil ............................................................................................................. 5-9
Model MH-12 Helmholtz Coil ........................................................................................................... 5-9
Lake Shore Reference Magnets .................................................................................................... 5-10
Model 4060 Standard Zero Gauss Chamber ................................................................................. 5-11
Model 4065 Large Zero Gauss Chamber ...................................................................................... 5-11
Model 4001 RJ-11 Cable Assembly............................................................................................... 5-12
Model 4002 RJ-11 to DB-25 Adapter............................................................................................. 5-12
Model 4003 RJ-11 to DE-9 Adapter............................................................................................... 5-12
Model 4022 Rack-Mount Kit........................................................................................................... 5-13
Model 4026 Dual Rack Mount Shelf .............................................................................................. 5-14
6-1
6-2
6-3
6-4
6-5
6-6
6-7
6-8
6-9
Power Fuse Access ......................................................................................................................... 6-3
DA-15 PROBE INPUT Connector Details........................................................................................ 6-4
Corrected and Monitor ANALOG OUTPUTS Connector Details ..................................................... 6-4
SERIAL I/O RJ-11 Connector Details .............................................................................................. 6-4
IEEE-488 Connector Details ............................................................................................................ 6-5
Model 4001 RJ-11 Cable Assembly Wiring Details ......................................................................... 6-6
Model 4002 RJ-11 to DB-25 Adapter Wiring Details ....................................................................... 6-6
Model 4003 RJ-11 to DE-9 Adapter Wiring Details ......................................................................... 6-6
Location Of Operating Software EPROM ........................................................................................ 6-7
C-1
C-2
C-3
C-4
C-5
C-6
C-7
Hall Generator Theory ....................................................................................................................C-2
Axial and Transverse Configurations .............................................................................................C-2
Typical Hall Generator Hookup ......................................................................................................C-4
Hall Generator Input Impedance ....................................................................................................C-4
Axial Hall Generator HGA-3010, HGA-3030, & HGCA-3010 Dimensions .....................................C-5
Transverse Hall Generator HGT-3010, HGT-3030, & HGCT-3020 Dimensions ...........................C-5
Axial Hall Generator HGA-2010 Dimensions .................................................................................C-6
iii
Lake Shore Model 450 Gaussmeter User’s Manual
LIST OF TABLES
Table No.
Title
Page
1-1
Model 450 Specifications ................................................................................................................1-3
4-1
4-2
4-3
Sample BASIC IEEE-488 Interface Program..................................................................................4-5
Serial Interface Specifications.........................................................................................................4-8
Sample BASIC Serial Interface Program........................................................................................4-9
C-1
C-2
C-3
Cryogenic Hall Generator Specifications ....................................................................................... C-5
Axial Hall Generator Specifications ............................................................................................... C-6
Transverse Hall Generator Specifications ..................................................................................... C-7
iv
Lake Shore Model 450 Gaussmeter User’s Manual
CHAPTER 1
INTRODUCTION
1.0
GENERAL
This chapter provides an introduction to the Lake Shore Model 450 Gaussmeter. The Model 450 was
designed and manufactured in the United States of America by Lake Shore Cryotronics, Inc. The
Model 450 is a high-accuracy, full-featured gaussmeter ideally suited for the laboratory. It features:
•
Field Measurement:
– High Accuracy with High Resolution.
– Auto Range.
– DC or AC Field Measurement.
– Individual Linearization of Hall Probes.
– Temperature Compensation of Hall Probes (certain models only).
•
Alphanumeric Display:
– 4¾-digit, 1 Part In 30,000 Resolution On All Ranges.
– 5¾-digit with DC and Filter, 1 Part In 300,000 Resolution.
– 2 Line by 20 Character Vacuum Fluorescent Display.
•
Other Major Operating Functions:
– Display Filter.
– Gauss or Tesla Units.
– Max Hold.
– Relative Reading.
– Audible Alarm for High and Low Field.
•
Interface:
– IEEE-488.2 Interface.
– Serial Interface (RS-232C Electrical Format).
– Corrected and Monitor Analog Outputs.
– Fast Data Acquisition Mode.
•
Probe Compatibility:
– High Stability Probes (HST) – 300 G to 300 kG Full-Scale Ranges.
– High Sensitivity Probes (HSE) – 30 G to 30 kG Full-Scale Ranges.
– Ultra High Sensitivity Probes (UHS) – 300 mG to 30 G Full-Scale Ranges.
•
Software Available:
– LabVIEW Driver Available.
We welcome comments concerning this manual. Although every effort has been made to keep it free
from errors, some may occur. When reporting a specific problem, describe it briefly and include the
appropriate paragraph, figure, table, and page number. Send comments to Lake Shore Cryotronics,
Attn: Technical Publications, 575 McCorkle Blvd., Westerville, Ohio 43082-8888. The material in this
manual is subject to change without notice.
Introduction
1-1
Lake Shore Model 450 Gaussmeter User’s Manual
1.1
MODEL 450 GAUSSMETER SYSTEM DESCRIPTION
The Model 450 is an extremely accurate full-featured gaussmeter. The Model 450 covers a wide range
of magnetic fields and applications. The instrument provides easy-to-use front panel programming and
a vacuum fluorescent alphanumeric display. This alphanumeric format allows for message-based front
panel operation. Most operations can be performed and monitored through the front panel keypad and
message display. A list of specifications is provided in Table 1-1.
The Model 450 measures fields in either gauss (G) or tesla (T). Set magnetic field ranges manually or
with auto ranging. The gaussmeter measures both DC and AC magnetic field values. In DC operation,
the display shows the DC field at the probe with the sign (orientation) followed by the appropriate field
units. In AC operation, the display shows a Peak or RMS value for the field at the probe.
The Max Hold function captures and displays the largest field magnitude seen since the last Max Reset.
The maximum value is shown in the lower display while the upper display contains the live field reading.
In AC RMS, the Max Hold feature displays the maximum RMS value of the waveform. In AC Peak, the
Max Hold feature displays the magnitude of the peak value of a non-periodic waveform.
The relative function lets the user see small variations in larger fields. The user defined setpoint
becomes the center or zero point of the relative reading and is shown on the lower line of the display.
The difference from the setpoint or the relative reading appears in the top display with a s symbol.
“Corrected” and “Monitor” analog outputs provide high accuracy and waveform monitoring. The
Corrected Analog Output is a DC voltage proportional to the reading displayed on the front panel. A
default voltage range of ±10 volts or ±3 volts for ±full scale field can be selected, or the voltage range
can be customized using the Analog Out function on the keypad.
The Monitor Analog Output is a real-time analog signal proportional to the magnetic field. The scale of
the Monitor Analog Output is ±3 volts for full scale of selected range. The Monitor Analog Output is not
as accurate as the Corrected Analog Output, but it has the full DC to 400 Hz bandwidth. The Monitor
Analog Output allows the user to observe the actual magnetic field waveform on an oscilloscope.
A Fast Data Acquisition Mode is included that shuts down the front panel display and provides up to
18 field readings per second over the IEEE-488 Interface. In addition, the Serial interface at 9600 Baud
can return 15 readings per second. Fast data mode is activated by issuing a FAST command using one
of the remote interfaces, then using the FIELD? command to return a string of data.
450_Front.bmp
Figure 1-1. Model 450 Gaussmeter Front Panel
1-2
Introduction
Lake Shore Model 450 Gaussmeter User’s Manual
Table 1-1. Model 450 Specifications
Measurement:
Number of Inputs: One
Update Rate: Five Per Second
Autorange: Yes
Electronic DC Accuracy: ±0.10% of reading ±0.005% of range at 25 °C
Drift of DC Electronics: 0.02% of reading + 0.003% of range/°C
AC Frequency Range: 10 to 400 Hertz
Overall AC Accuracy: ±5% or better
AC Peak Accuracy: ±5% typical
Field Ranges/Resolutions: Are provided in the following three tables; listed by type of probe:
High Stability Probe (HST)
Range
±300 kG
±30 kG
±3 kG
±300 G
Gauss
Resolution
AC or DC
DC Filter On
w/ Filter Off
±0.01 kG
±0.001 kG
±0.001 kG
±0.0001 kG
±0.0001 kG
±0.00001 kG
±0.01 G
±0.001 G
Range
±30 T
±3 T
±300 mT
±30 mT
Tesla
Resolution
AC, or DC
DC Filter On
w/ Filter Off
±0.001 T
±0.0001 T
±0.0001 T
±0.00001 T
±0.01 mT
±0.001 mT
±0.001 mT
±0.0001 mT
High Sensitivity Probe (HSE)
Range
±30 kG
±3 kG
±300 G
±30 G
Gauss
Resolution
AC or DC
DC Filter On
w/ Filter Off
±0.001 kG
±0.0001 kG
±0.0001 kG
±0.00001 kG
±0.01 G
±0.001 G
±0.001 G
±0.0001 G
Range
±3 T
±300 mT
±30 mT
±3 mT
Tesla
Resolution
AC or DC
DC Filter On
w/ Filter Off
±0.0001 T
±0.00001 T
±0.01 mT
±0.001 mT
±0.001 mT
±0.0001 mT
±0.0001 mT
±0.00001 mT
Ultra-High Sensitivity Probe (UHS)
Range
±30 G
±3 G
±300 mG
Gauss
Resolution
AC or DC
DC Filter On
w/ Filter Off
±0.001 G
±0.0001 G
±0.0001 G
±0.00001 G
±0.01 mG
±0.001 mG
Range
±3 mT
±300 µT
±30 µT
Tesla
Resolution
AC or DC
DC Filter On
w/ Filter Off
±0.0001 mT
±0.00001 mT
±0.01 µT
±0.001 µT
±0.001 µT
±0.0001 µT
Interfaces:
Audible Alarm: High and Low Setpoints
Corrected Analog Output Accuracy: ±0.1% of ±3 volt or ±10 volt range
Monitor Analog Output Accuracy: Probe Dependent
IEEE-488 Capabilities: Complies with IEEE-488.2 = SH1,AH1,SR1,RL1,PP0,DC1,DT0,C0,E1
Serial Communication in RS-232C Electrical Format: 300, 1200, or 9600 Baud;
RJ-11 connector
Fast Data Acquisition Mode: (Refer to Paragraph 3.16)
With the IEEE-488 Interface: 18 reading per second
With Serial Interface at 9600 Baud: 15 readings per second
Introduction
1-3
Lake Shore Model 450 Gaussmeter User’s Manual
Table 1-1. Model 450 Specifications (Continued)
Front Panel:
Display Type: 2 line by 20 characters, vacuum fluorescent
Field Reading
Units:
kG
G
mG
T
mT
uT
0.00
0.00
kG DC
¨ ªR
kG MAX
Probe Orientation
(DC Only)
+
Alarm
DC
PK
RMS
Relative
On
Remote
On
Lower row used for Max Hold (MAX) (shown above) and Relative
Setpoint (SP) readings. Also used for various on/off messages.
C-450-1-2.eps
Display Resolution: 4¾-digit, 5¾-digit with DC & Filter (see field ranges on previous page)
Display Units: Gauss (G) or tesla (T)
Instrument General:
Ambient Temperature Range: 15 °C to 35 °C (59 °F to 95 °F)
Power Requirement: 100, 120, 220, 240 VAC (+5% –10%), 50 or 60 Hz, 20 watts
Size: 217 mm wide × 90 mm high × 317 mm deep (8.54 × 3.5 × 12.5 inches);
half-rack package
Weight: 3 kilograms (6.6 pounds)
1-4
Introduction
Lake Shore Model 450 Gaussmeter User’s Manual
1.2
SAFETY SUMMARY
Observe the following general safety precautions during all phases of instrument operation, service,
and repair. Failure to comply with these precautions or with specific warnings elsewhere in this manual
violates safety standards of design, manufacture, and intended use of the instrument. Lake Shore
Cryotronics, Inc. assumes no liability for customer failure to comply with these requirements.
The Model 450 protects the operator and surrounding area from electric shock or burn, mechanical
hazards, excessive temperature, and spread of fire from the instrument. Environmental conditions
outside of the conditions below may pose a hazard to the operator and surrounding area.
• Temperature: 5° to 40° C.
• Maximum relative humidity: 80% for temperatures up to 31° C decreasing linearly to 50% at 40° C.
• Power supply voltage fluctuations not to exceed ±10% of the nominal voltage.
Ground The Instrument
To minimize shock hazard, connect instrument chassis and cabinet to electrical ground. The
instrument is equipped with a 3-conductor AC power cable; either plug it into an approved 3-contact
outlet or use a 3-contact adapter with the grounding wire (green) firmly connected to a ground (safety
ground) at the power outlet. The power jack and mating plug of the power cable meet Underwriters
Laboratories (UL) and International Electrotechnical Commission (IEC) safety standards.
Do Not Operate In An Explosive Atmosphere
Do not operate the instrument in the presence of flammable gases or fumes. It is a safety hazard.
Keep Away From Live Circuits Inside the Instrument
Operating personnel must not remove instrument covers. Refer component replacement and internal
adjustments to qualified maintenance personnel. Do not replace components with power cable
connected. To avoid injuries, always disconnect power and discharge circuits before touching them.
Do Not Substitute Parts Or Modify Instrument
Because of the danger of introducing additional hazards, do not install substitute parts or perform any
unauthorized modification to the instrument. Return the instrument to an authorized Lake Shore
Cryotronics, Inc. representative for service and repair to ensure that safety features are maintained.
Do Not Place Conductive Probes Against Exposed Electrical Circuits
Some gaussmeter probes are equipped with conductive sheaths. Keep these probes away from live
electrical circuits near magnetic fields.
1.3
SAFETY SYMBOLS
Introduction
1-5
Lake Shore Model 450 Gaussmeter User’s Manual
This Page Intentionally Left Blank
1-6
Introduction
Lake Shore Model 450 Gaussmeter User’s Manual
CHAPTER 2
INSTALLATION
2.0
GENERAL
This chapter covers general Model 450 installation instructions: Inspection and unpacking in Paragraph
2.1, repackaging for shipment in Paragraph 2.2, definition of rear panel connections in Paragraph 2.3,
and initial setup and system checkout procedure in Paragraph 2.4.
2.1
INSPECTION AND UNPACKING
Inspect shipping containers for external damage. Make all claims for damage (apparent or concealed)
or partial loss of shipment in writing to Lake Shore within five (5) days from receipt of goods. If damage
or loss is apparent, please notify the shipping agent immediately.
Open the shipping containers. Use the packing list included with the system to verify receipt of the
instrument, sensor, accessories, and manual. Inspect for damage. Inventory all components supplied
before discarding any shipping materials. If there is freight damage to the instrument, file proper claims
promptly with the carrier and insurance company and notify Lake Shore. Notify Lake Shore immediately
of any missing parts. Lake Shore cannot be responsible for any missing parts unless notified within 60
days of shipment. Refer to the standard Lake Shore Warranty on the A Page (immediately behind the
title page).
2.2
REPACKAGING FOR SHIPMENT
To return the Model 450, sensor, or accessories for repair or replacement, obtain a Return Goods
Authorization (RGA) number from Technical Service in the United States, or from the authorized
sales/service representative from which the product was purchased. Instruments may not be accepted
without a RGA number. When returning an instrument for service, Lake Shore must have the following
information before attempting any repair.
1. Instrument model and serial number.
2. User name, company, address, and phone number.
3. Malfunction symptoms.
4. Description of system.
5. Returned Goods Authorization (RGA) number.
Wrap instrument in a protective bag and use original spacers to protect controls. Repack the system in
the Lake Shore shipping carton (if available) and seal it with strong paper or nylon tape. Affix shipping
labels and FRAGILE warnings. Write the RGA number on the outside of the shipping container or on
the packing slip.
Because of their fragility, Lake Shore probes ship in special cardboard and foam boxes. Retain these
boxes to store probes when not in use, or return probes to Lake Shore for re-calibration or repair.
Installation
2-1
Lake Shore Model 450 Gaussmeter User’s Manual
2.3
DEFINITION OF REAR PANEL CONNECTIONS
The Model 450 rear panel consists of the power and fuse assembly, IEEE-488 Interface Connector,
Serial I/O Connector, Corrected and Monitor Analog Output BNCs, and a DA-15 Probe Input
Connector. See Figure 2-1, Refer to Chapter 5 for rear panel connector pin-out details.
450_Back.bmp
Figure 2-1. Model 450 Rear Panel
CAUTION:
Verify AC Line Voltage shown in the fuse holder window is appropriate for the
intended AC power input. Also remove and verify the proper fuse is installed before
plugging in and turning on the instrument.
CAUTION:
Always turn off the instrument before making any rear panel connections. This is
especially critical when making probe to instrument connections.
1. IEEE-488 Interface Connector. The standard 24-pin connector connects the gaussmeter to any
computer suitably equipped with a IEEE-488 interface. Refer to Paragraph 4.1.
2. Power and Fuse Assembly. The power and fuse assembly is the primary entry and control point
for AC power to the unit. The assembly consists of three parts: power line jack, power on/off switch,
and the fuse drawer. The line cord connects to the power line jack. The on/off switch controls power
to the unit. The “I” symbol shows when power is on and the “O” shows when power is off. The fuse
drawer has a dual purpose: housing the fuse and setting unit input power.
3. Serial I/O Connector. The Serial I/O (Input/Output) Connector accepts the standard RJ-11
telephone connector. Lake Shore offers RJ-11 to DE-9 or DB-25 Adapters that permit connection to
a computer. Refer to Paragraph 4.2.
4. Corrected and Monitor Analog Outputs. Analog outputs are available on two Bayonet Nut
Connectors (BNCs). The signal is on the center conductor while the outer casing is for ground. Both
outputs may be used simultaneously. The corrected output is not a real-time signal, but updates at
the same rate as the display. The default range of the corrected output is ±3 volts equals ± full
scale for the range. However, the scaling of the corrected output may be reconfigured. The monitor
output is a live analog signal proportional to the magnetic flux density waveform. Refer to
Paragraph 3.12 for further operational information.
5. Probe Input Connector. The probe plugs into the DA-15 connector. Always turn off the instrument
before connecting the probe. Align the probe connector with the rear panel connector and push
straight in to avoid bent pins. For best results, secure the connector to the rear panel using the two
thumbscrews. A tight connector keeps the cable secure and prevents interference. Refer to
Paragraph 3.15 for additional probe considerations.
2-2
Installation
Lake Shore Model 450 Gaussmeter User’s Manual
2.4
LINE INPUT ASSEMBLY
This section covers line voltage and fuse verification in Paragraph 2.4.1, power cord in Paragraph 2.4.2,
and power switch in Paragraph 2.4.3.
2.4.1
Line Voltage and Fuse Verification
To verify proper line voltage selection look at the indicator in the window on the fuse drawer of the
line input assembly. Line voltage should be in the range shown in the specifications listed on the back
of the instrument. See Figure 2-2. If not, change the line voltage selector per instructions in
Paragraph 6.3. The fuse must be removed to verify its value, refer to the procedure in Paragraph 6.4.
Use slow-blow fuses of the value specified on back of the instrument.
2.4.2
Power Cord
The Model 450 includes a three-conductor power cord. Line voltage is present across the outer two
conductors. The center conductor is a safety ground and connects to the instrument metal chassis.
For safety, plug the cord into a properly grounded three-pronged receptacle.
2.4.3
Power Switch
The power switch turns the instrument On and Off and is located in the line input assembly on the
instrument rear. When l is raised, the instrument is On. When O is raised, the instrument is Off.
450_Power.bmp
Figure 2-2. Line Input Assembly
2.5
PROBE INPUT CONNECTION
WARNING:
Some probes used with the gaussmeter have conductive parts. Never probe near
exposed live voltage. Personal injury and damage to the instrument may result.
CAUTION:
Always turn off the instrument before making any rear panel Probe Input connections.
The Lake Shore probe plugs into the 15 pin D-style connector on the rear panel. Turn the instrument off
before attaching the probe. Align the probe connector with the rear panel connector and push straight in
to avoid bending the pins. For best results, secure the connector to the rear panel using the two
thumbscrews. A tight connector keeps the cable secure and prevents interference. Refer to Paragraph
3.15 for additional probe considerations.
When power is turned on, the instrument reads parameters from probe memory. The probe is ready to
use. No parameters need to be entered into the Model 450. However, the Zero Probe function should
be performed the first time a probe is used with the instrument and periodically during use.
Installation
2-3
Lake Shore Model 450 Gaussmeter User’s Manual
2.5.1
Attachment To A Hall Generator
The Model MCBL-6 has a 15 pin D-Style connector on one end for direct attachment to the
PROBE INPUT connection on the back panel of the Model 450 Gaussmeter. Four tinned wires are
provided for connection to the Hall Generator. The leads may be soldered directly to these wires.
Current to
Sensor
Hall Voltage
from Sensor
{
{
Green Wire (–)
Red Wire (+)
Blue Wire (–)
6 Foot Cable to
Gaussmeter
Yellow Wire (+)
F-460-2-3.eps
Figure 2-3. Model MCBL-6 User Programmable Cable Accessory
CAUTION: The Hall Generator should be isolated from all line voltages (or voltages referenced
to earth ground). If not, damage to the Model 450 Gaussmeter is almost a certainty.
Refer to Appendix C for a complete list of compatible Hall generators manufactured by Lake Shore.
Once connections are made, refer to Paragraph C6.0 for instructions on using the Hallcall.exe
program to store probe parameters in the internal EPROM.
2.6
CORRECTED AND MONITOR ANALOG OUTPUTS
Analog outputs are available on Bayonet Nut Connectors (BNCs). The signal is on the center conductor
while the outer casing is for ground. Both outputs may be used simultaneously. The Corrected output is
not a real-time signal, but is updated at the same rate as the display. The Monitor output is a live analog
signal proportional to the magnetic flux density waveform of the respective channel. Refer to Paragraph
3.12 for further operational information.
2.7
INITIAL SETUP AND SYSTEM CHECKOUT PROCEDURE
This procedure verifies basic unit operation before initial use for measurements.
CAUTION: Check power source for proper voltage before connecting line cord to the
Model 450. Check power setting on fuse drawer window. Damage may occur
if connected to improper voltage.
1. Check power source for proper voltage. The Model 450 operates with 100, 120, 220, or 240
(+5%, –10%) AC input voltage.
2. Check fuse drawer window for proper voltage setting. If incorrect, refer to Paragraph 5.2.
3. Ensure power switch is off (O).
CAUTION: The probe must be connected to the rear of the unit before applying power to
the gaussmeter. Damage to the probe may occur if connected with power on.
4. Plug in the DA-15 probe connector to PROBE INPUT. Use thumbscrews to tighten connector to
unit.
5. Connect and check all other rear panel connections (IEEE-488, SERIAL I/O, or ANALOG
OUTPUTS) before applying power to the unit.
6. Plug line cord into receptacle.
2-4
Installation
Lake Shore Model 450 Gaussmeter User’s Manual
Initial Setup And System Checkout Procedure (Continued)
7. Turn power switch on (l). The front panel display turns on and briefly displays the following
message.
Lake Shore 450
Field Monitor
8. The normal gaussmeter display appears, similar to the following screen.
+
0.00
kG
DC
NOTE: For best results, the instrument and probe should warm up for at least 5 minutes before
zeroing the probe, and at least 30 minutes for rated accuracy. The probe and the zero
gauss chamber should be at the same temperature.
Some Lake Shore probes come with a clear plastic sleeve to protect the probe tip when not in use. The
sleeve slides up and down the probe cable. To place the probe in the zero gauss chamber, slide the
protective sleeve back, exposing the probe tip, before placing the tip in the chamber.
9. Place the probe in the zero gauss chamber and press the front panel Zero Probe key. The display
to the right appears.
Press
Probe
Enter With
At Zero
10. Press the Enter key. The *CALIBRATING* message briefly displays, followed by the normal
display. Do not move the probe while the *CALIBRATING* message displays.
NOTE: If the unit performs well to this point, the unit is functioning properly. If there is a reference
magnet available, continue the test using the magnet to verify the Model 450 accuracy.
11. If continuing the procedure with a reference magnet, verify the probe accommodates the magnet
range. Use the Range Select key to select the proper range (or press Auto Range). Set the
display for DC. Finally, since probe orientation is very selective, press the Max Hold key to capture
the highest reading.
CAUTION: Take care when handling the probe; its tip is very fragile. Any excess force
may break it.
NOTE: Probe readings depend on the angle of the tip in relation to the magnetic field. The greater
the angle, the higher the percentage of error. For example, a 5° angle causes a 0.4% error,
a 10° angle induces a 1.5% error, etc. Refer to Paragraph 3.15.
Installation
2-5
Lake Shore Model 450 Gaussmeter User’s Manual
Initial Setup And System Checkout Procedure (Continued)
12. Carefully place probe in contact with reference magnet and hunt a bit for the maximum reading.
For this example, we used a 999 ±1% Gauss probe reference magnet.
+0.9729
0.9952
kG
kG
DC
MAX
The top line displays the current reading. The bottom line displays the maximum reading captured,
which is within the tolerance of our reference magnet. The top line continually changes as the probe
moves, but the bottom remains fixed on the highest reading. To capture a new maximum value, press
the Max Reset key.
After successfully completing this checkout procedure, the unit is ready for normal operation.
2-6
Installation
Lake Shore Model 450 Gaussmeter User’s Manual
CHAPTER 3
OPERATION
3.0
GENERAL
This chapter covers aspects of Model 450 operation: Front panel controls are defined in Paragraph 3.1,
front panel functions in Paragraphs 3.2 thru 3.13, default settings in Paragraph 3.14, and probe handling
considerations in Paragraph 3.15. Refer to Chapter 4 for remote operation (IEEE-488/Serial).
3.1
DEFINITION OF FRONT PANEL CONTROLS
The front panel consists of two major sections: the 21 front panel keys described in Paragraph 3.1.1, and the
2 row by 20 character vacuum fluorescent display described in Paragraph 3.1.2.
3.1.1
Front Panel Keypad Definitions
Max Reset: Works with Max Hold function. Returns Max reading to normal field reading. Refer to
Paragraph 3.2.
Max Hold: Turns Max Hold feature ON and OFF. Captures and displays the highest field reading. Use Max
Reset key to clear reading. Refer to Paragraph 3.2.
Zero Probe: Zeros or nulls effects of ambient low level fields from the probe. To use, place tip of probe into
Zero Gauss Chamber, press Zero Probe, then Enter. Refer to Paragraph 3.3.
Select Range: Manually selects field measurement range. Available ranges depend on which probe is
installed. Refer to Paragraph 3.4.
Auto Range: Turns Auto Range feature ON and OFF. Allows the Model 450 to automatically select field
measurement range. Refer to Paragraph 3.4.
AC/DC: Selects periodic (AC) or static (DC) magnetic fields. The AC selection provides the option of Peak or
RMS readings. Refer to Paragraph 3.5.
Peak/RMS: The AC selection provides the option of Peak or Root Mean Square (RMS) readings. Also use
Peak with the Max Hold feature to measure single peaks. Refer to Paragraph 3.5.
450_Front.bmp
Figure 3-1. Model 450 Front Panel
Operation
3-1
Lake Shore Model 450 Gaussmeter User’s Manual
Front Panel Keypad Definitions (Continued)
Filter: Turns filter ON or OFF and configures filter. Filter ON enables high resolution DC readings. Press
and hold Filter to select Field Compensation and Temperature Compensation ON or OFF. Refer to
Paragraph 3.6.
Gauss/Tesla: Changes display units from gauss to tesla. Gauss (G) is used in the cgs system, where
1 G = 10-4 T. Tesla (T) is used in the SI system, where 1 T = 104 G. Refer to Paragraph 3.7.
Relative Set: With the relative feature turned ON, this key captures the field reading as the relative
setpoint, or the user may enter a number via the keypad. Works with the Relative On/Off key. Refer to
Paragraph 3.8.
Relative On/Off: Displays the positive or negative deviation from setpoint in the lower line of the display.
Often used to offset large magnetic fields. May also be used with Max Hold and Alarm. Refer to
Paragraph 3.8.
Alarm Set: Sets high and low alarm points. The alarm setpoints are absolute (unsigned) i.e., the positive or
negative aspect of the field reading is ignored. Refer to Paragraph 3.9.
Alarm On/Off: Turns alarm feature ON or OFF. After setting high and low alarm points with Alarm Set, the
alarm is activated whenever the magnetic field goes inside or outside the range defined—regardless of the
sign (positive or negative) of the reading. Press and hold Alarm On/Off to turn the alarm ON or OFF and
select the alarm to sound inside or outside the range. Refer to Paragraph 3.9.
Local: Selects local or remote operation. When set to Local, the unit responds to front panel controls. When
set to Remote, the unit is controlled via the IEEE-488 Interface. Remote users have the option to lock out
front panel controls. Refer to Paragraph 3.10.
Address: If using the IEEE-488 Interface, press this key to adjust the bus address of the Model 450 and
terminators. Refer to Paragraph 3.10.
Baud: If using the Serial Interface, press this key to select the Model 450 Baud Rate from 300, 1200, or 9600.
Refer to Paragraph 3.11.
Analog Out: Adjusts the scaling of the Corrected Analog Output. The default setting makes the currently
selected range the maximum and minimum values corresponding to the +3 volt and –3 volt outputs. The
Monitor Analog Output scaling cannot be modified. Refer to Paragraph 3.12.
Escape: Terminates a function without changing existing settings. Press and hold Escape for about
20 seconds to reset the instrument, returning many parameters to factory defaults. Refer to Paragraph 3.14.
▲: Toggles between various settings shown in the display and increments a numerical display.
▼: Toggles between various settings shown in the display and decrements a numerical display.
Enter: Accepts changes in the field display. Press and hold Enter to access the Keypad Lock display, and
enter a 3-digit code to lockout the keypad from accepting changes.
3-2
Operation
Lake Shore Model 450 Gaussmeter User’s Manual
3.1.2 Front Panel Display
In normal operation, the two row by twenty character vacuum fluorescent display provides magnetic readings
on the top row and special information or readings on the bottom row. Other information displays when using
the various functions on the keypad. Each character is comprised of a 5 by 7 dot matrix. See Figure 3-2.
Field Reading
Units:
kG
G
mG
T
mT
uT
0.00
0.00
kG DC
¨ ªR
kG MAX
Probe Orientation
(DC Only)
+
Alarm
DC
PK
RMS
Relative
On
Remote
On
Lower row used for Max Hold (MAX) (shown above) and Relative
Setpoint (SP) readings. Also used for various on/off messages.
C-450-1-2.eps
Figure 3-2. Front Panel Display Definition
3.2 MAX HOLD AND MAX RESET
Max Hold displays the largest field magnitude
measured since the last Max Reset. Press Max
Hold to view the maximum value in the lower line
of the display and the field reading in the upper line.
Max Hold may also be used in conjunction with the Relative display (Refer to Paragraph 3.7).
+ 0 .5 7 2 9
0 .5 8 9 2
kG
kG
DC
MAX
Max Reset clears the Max Hold value. The Max Hold value also resets upon power up or when changing
from AC or DC.
Max Hold functions differently with AC and DC fields. In DC operation, Max Hold captures the largest
magnitude field reading. This monitors slowly changing signals. A field change not visible on the display can
not be recorded in DC Max Hold. The display shows only the magnitude of the maximum reading.
In AC RMS operation, Max Hold captures the maximum RMS value (i.e., operates the same as DC Max). In
AC Peak operation, Max Hold uses a hardware circuit to trap peaks in the Hall voltage. In this mode, the unit
displays the magnitude of the actual peak of an impulse or event. For best accuracy, the event must be at full
amplitude for at least a few milliseconds.
3.3
ZERO PROBE
The zero probe function cancels out the zero offset of the probe or small magnetic fields. It is normally used in
conjunction with the zero gauss chamber, but may also be used with an unshielded probe (registering the
local earth magnetic field). To cancel large magnetic fields, use the Relative function.
NOTE: For best results, allow the instrument and probe to warm up for at least 5 minutes before
zeroing the probe, and at least 30 minutes for rated accuracy. The probe and the zero
gauss chamber should be at the same temperature.
To zero the probe in the zero gauss chamber, first
allow the temperature of the probe and chamber
to equalize. (A large temperature discrepancy
affects the quality of the calibration.) Carefully
place the probe tip into the chamber. Orientation
of the probe is not critical. Once inserted, press Zero Probe to display the screen above.
Press
Probe
E n t e r W it h
At Zero
Press Enter to display the *CALIBRATING* message, followed by a return to the normal display. Do not
move the probe while calibrating. The probe is now zeroed. For best results, periodically zero the probe.
Operation
3-3
Lake Shore Model 450 Gaussmeter User’s Manual
3.4
SELECT RANGE AND AUTO RANGE
The Model 450 reads each Lake Shore probe type: High Stability, High Sensitivity, or Ultra-High Sensitivity.
These probes sense fields as low as 0.01 mG and as high as 300 kG. The tables below list full scale ranges
for each probe sensitivity, along with fixed display resolution.
High Stability Probe (HST)
Range
±300 kG
±30 kG
±3 kG
±300 G
Gauss
Resolution
AC, or DC
DC Filter On
w/ Filter Off
±0.01 kG
±0.001 kG
±0.001 kG
±0.0001 kG
±0.0001 kG
±0.00001 kG
±0.01 G
±0.001 G
Range
±30 T
±3 T
±300 mT
±30 mT
Tesla
Resolution
AC, or DC
DC Filter On
w/ Filter Off
±0.001 T
±0.0001 T
±0.0001 T
±0.00001 T
±0.01 mT
±0.001 mT
±0.001 mT
±0.0001 mT
High Sensitivity Probe (HSE)
Range
±30 kG
±3 kG
±300 G
±30 G
Gauss
Resolution
AC, or DC
DC Filter On
w/ Filter Off
±0.001 kG
±0.0001 kG
±0.0001 kG
±0.00001 kG
±0.01 G
±0.001 G
±0.001 G
±0.0001 G
Range
±3 T
±300 mT
±30 mT
±3 mT
Tesla
Resolution
AC, or DC
DC Filter On
w/ Filter Off
±0.0001 T
±0.00001 T
±0.01 mT
±0.001 mT
±0.001 mT
±0.0001 mT
±0.0001 mT
±0.00001 mT
Ultra-High Sensitivity Probe (UHS)
Range
±30 G
±3 G
±300 mG
Gauss
Resolution
AC, or DC
DC Filter On
w/ Filter Off
±0.001 G
±0.0001 G
±0.0001 G
±0.00001 G
±0.01 mG
±0.001 mG
For manual ranging, press Select Range to view
the full scale value for the present range. The
display to the right appears.
Range
±3 mT
±300 µT
±30 µT
Tesla
Resolution
AC, or DC
DC Filter On
w/ Filter Off
±0.0001 mT
±0.00001 mT
±0.01 µT
±0.001 µT
±0.001 µT
±0.0001 µT
S e le c t W it h ¨ ©
+ / -3 .0 0 0 0 k G R a n g e
Press Select Range or the ▲ or ▼ keys to cycle through allowable full-scale ranges for the installed probe.
Press Enter to accept the new range or Escape to retain the old range. Changing ranges in this way disables
the Auto Range function until Auto Range is pressed.
NOTE: In AC Peak Mode only, you cannot select the lowest range for the installed probe.
This is true for both Manual and Auto Range.
In Auto Range mode, the Model 450 selects the range with the best resolution for the measured field. It can
take up to 2 seconds for Auto Range to work, so
manual ranging may be better in some
conditions. Press Auto Range to display the
screen to the right.
S e le c t W it h ¨ ©
A u to R a n g e ¡ O n
Off
Press Auto Range or the ▲ or ▼ keys to cycle between On and Off. Push Enter to accept the new setting or
Escape to retain the old setting and return to the normal display.
Do not use Auto Ranging with Peak and Max Hold operation or during small field measurement in a large
background field, such as measuring a small DC field in presence of a large AC field, or vice versa.
3-4
Operation
Lake Shore Model 450 Gaussmeter User’s Manual
3.5
AC/DC AND PEAK/RMS
The AC/DC key toggles between AC and DC measurements. The annunciator immediately changes from
“DC” to “PK” or “RMS,” as applicable. One update cycle is required for a new display value. The Model 450
updates the field reading 5 times per second. For faster updates, refer to Fast Data Mode in Paragraph 3.16.
In DC operation, the display shows the DC field at the probe with sign (orientation) followed by the
appropriate field units, the letters DC, displaying 4¾ digits with filter OFF or 5¾ digits with Filter ON. The DC
value is available over the IEEE-488 and Serial Interfaces and both Analog Outputs.
In AC operation, select either RMS or Peak. Both meet specified accuracy from 10 to 400 Hz. The lowest
range for the type probe installed is not available in the AC Peak mode. The AC RMS reading is a
measurement of true RMS, defined as the square root of the average of the square of the field function taken
through one period. The RMS reading works on complex waveforms to a crest factor of 7 and rejects the DC
component if it is not large enough to overload the selected range.
The AC Peak readings can be used in two different ways. With Max Hold OFF, it measures the Peak (Crest)
of a periodic, symmetrical waveform. If field change at the probe is unpredictable, the peak reading will not
always show the largest field value. In this case, check monitor output with an oscilloscope to see how the
reading relates to the field. With Max Hold ON, the Peak reading measures the amplitude of a single peak
like a magnetizing pulse. It captures the reading until reset with Max Reset.
The AC value is available over the IEEE-488 and Serial Interfaces. The Corrected Analog Output yields a DC
voltage representation of the Peak or RMS reading, while the Monitor Analog Output yields a true analog
waveform. (In fact, the Monitor Analog Output is not affected by the selection of AC or DC.)
When changing to AC or DC, the unit maintains previously established Relative and Alarm setpoints, but Max
Hold operation changes (Paragraph 3.3).
3.6
FILTER
The Filter key initiates the display filter function (Paragraph 3.6.1). Press and hold Filter for about 5 seconds
to display field and temperature compensation (Paragraph 3.6.2).
3.6.1
Display Filter
The display filter function quiets the display making it more readable when the probe is exposed to a noisy
field. Take care when using the filter on changing fields; it may level off peaks and slow instrument response.
Users may configure the filter function to view desired field changes and block noise. The filter also quiets
noise within the instrument by adding a digit of usable resolution in DC.
To turn ON the display filter, press Filter to display the screen to the right. Press Filter or the ▲ or ▼ keys to
toggle between ON and OFF. Press Enter to
accept the new setting or Escape to retain the
old setting and return to the normal display.
With Filter turned on, two additional displays
appear: the Filter Points display and the Filter
Window display. The Filter Points display sets the
number of points to use in the filter algorithm.
Enter from 2 to 64 points; 8 is the default. The
unit takes one point each display update cycle,
so filter settling time depends on update speed
and number of samples.
S e le c t
F ilt e r
W it h
On
¨©
¡Off
S e le c t W it h ¨ ©
F ilt e r P o in t s 0 8
The Filter Window display sets a limit for
restarting the filter. If a single field reading differs
from the filter value by more than the limit
specified, the instrument assumes an intentional
change and restarts the filter at the new reading
value. This allows faster instrument response to changing fields than if the filter functioned continually. Enter
settings from 1% to 10%; 1% is the default.
S e le c t W it h ¨ ©
F ilt e r W in d o w 0 1 %
Operation
3-5
Lake Shore Model 450 Gaussmeter User’s Manual
The Model 450 uses two
different filter algorithms
that result in slightly
different settling time
computations. For 2 to 8
filter points, a linear
average is used for the
fastest response. In this
case, the filter settles in
the same number of
samples as entered. For
example, when set at 8
points and updating at 5
readings per second,
the filter settles in 1.6
seconds.
Exponential Response with Filter Points set to 9
Linear Response with Filter Points set to 8
Step Change in Magnetic Field
For 9 to 64 filter points,
Seconds
an exponential algorithm
2.5
5
7.5
10
12.5
15
is used for a smooth
response. The settling
time for a 1% change to
20
40
50
60
0
10
30
Figure 3-3. Display Filter Response Examples
full display resolution is
Readings
about the same as the
number of filter points in seconds. For example, a setting of 10 filter points settles in about 10 seconds.
Figure 3-3 illustrates the difference between linear and exponential response.
3.6.2
Field and Temperature Compensation
NOTE: Unless there is a specific reason, Lake Shore strongly advises customers not to turn field and
temperature compensation off; it may reduce reading accuracy substantially.
To disable Field and Temperature
Compensation, press and hold the Filter key for
about 5 seconds to display the Field
Compensation screen. To improve accuracy, all
probes have a magnetic field compensation table
stored in a PROM. Turning Field Compensation OFF causes the Model 450 to ignore this table. Press the ▲
or ▼ keys to cycle between ON and OFF. Push Enter to accept the new setting or Escape to retain the old
setting and return to the normal display. If the probe has no field compensation, the setting is ignored.
S e le c t W it h ¨ ©
F ie ld C o m p
On ¡Off
Some high-sensitivity probes also feature temperature compensation. Turning Temperature Compensation
OFF causes the Model 450 to ignore this data.
Press the ▲ or ▼ keys to cycle between ON and
OFF. Push Enter to accept the new setting or
Escape to retain the old setting and return to the
normal display. If the probe has no temperature
compensation, the setting is ignored.
S e le c t W it h ¨ ©
Temp Comp
On ¡Off
3.7
GAUSS / TESLA
The Model 450 displays magnetic field values in gauss (G) or tesla (T). Press Gauss/Tesla to toggle the
display between the two units. The relation between gauss and tesla is 1 G = 0.0001 T, or 1 T = 10,000 G.
When field units are changed, relative and alarm setpoints convert to the new units with no interruption in
operation. The Corrected and Monitor Analog Outputs are not affected by a change in units.
When tesla is selected, the Model 450 displays AC or DC field values followed by T for tesla, mT for millitesla,
or uT for microtesla and formats field values over the IEEE-488/Serial Interface accordingly.
When gauss is selected, the Model 450 displays AC or DC field values followed by kG for kilogauss, G for
gauss, or mG for milligauss and formats field values over the IEEE-488/Serial Interface accordingly.
3-6
Operation
Lake Shore Model 450 Gaussmeter User’s Manual
3.8
RELATIVE SET AND RELATIVE ON/OFF
The relative function lets the user see small
variations in larger fields. Set the setpoint (or
center) of the relative reading with Relative Set.
There are two ways to enter the relative setpoint.
The first method captures the field reading, nulling the present field. The field reading displays as the setpoint
upon pressing Relative Set. Press Enter to accept the setpoint or Escape to retain the old value and quit the
Relative Set function.
E n te r
R e la t iv e S e t p .
+ 0 .5 3 9 2 k G
The second method is by keypad entry. Press Relative Set and change the setpoint by pressing number keys
or using the ▲ or ▼ keys. Press Select Range to enter a setpoint different from the current range. Press
Enter to accept the new setpoint or Escape to return to the old value.
Once the relative setpoint is established, push
Relative On/Off to initiate the relative function.
The “Relative On” message briefly appears on
the lower line of the display, followed by the
selected setpoint (SP). The plus or minus
deviation from that setpoint displays on the upper line. A small delta (¨) signifies the relative display.
-0 .0 0 3 7
+ 0 .5 3 9 2
kG D C
kG S P
¨
The relative feature also interacts with other features. When alarm is active, the alarm points follow the
relative reading. When Relative and Max Hold
functions are used at the same time, the relative
reading is still displays on the top line with proper
annunciators, but the bottom line shows the
relative maximum instead of the relative setpoint.
-0 .0 0 3 7
+ 0 .0 0 5 4
kG D C ¨
kG M A X
Press Max Hold again to turn OFF the maximum hold function, returning the relative reading to the display.
Press Relative On/Off to turn OFF the relative function. The “Relative Off” message displays.
3.9
ALARM SET AND ALARM ON/OFF
The alarm gives an audible and visual indication when the field value is outside or inside a user-specified
range. Two settings define alarm operating parameters. First is whether the audible alarm is ON or OFF.
Second is whether readings inside or outside the defined field range trigger the alarm. (Default settings are
audible alarm on and alarm triggered outside the
low and high alarm setpoints.) To set these
parameters, press and hold Alarm On/Off until
the display to the right appears. Use the ▲ or ▼
keys to cycle between audible alarm on or off.
Press Enter to accept the new value or Escape
to step to the next function and retain the old
setting.
S e le c t W it h
A u d ib le ¡ O n
The Model 450 proceeds to the next display:
¨©
Off
S e le c t W it h ¨ ©
A la r m In s id e ¡ O u t s id e
Use the ▲ or ▼ keys to cycle between the alarm
triggered inside or outside alarm setpoints. Press Enter to accept the changes or Escape to exit the function
and retain the old settings. All alarm functions are also available over the IEEE-488 and Serial Interfaces.
Operation
3-7
Lake Shore Model 450 Gaussmeter User’s Manual
The example below details operation with the Alarm Outside setting. For example, with the reading centered
on 1 kG, the high alarm point at 1.5 kG, and the low alarm point at 0.5 kG, the diagram below illustrates when
the alarm is ON or OFF.
Alarm
On
–3 kG
–2 kG
Alarm
Off
Alarm
On
Alarm
Off
–1 kG
0 kG
+1 kG
Alarm
On
+2 kG
+3 kG
Low Alarm
Point
Example of operation with
alarm triggered by
readings OUTSIDE user
defined setpoints.
High Alarm Point
To enter this alarm setup, push Alarm Set. The
unit prompts for the High Alarm Point:
H ig h
A la r m P o in t
+ 1 .5 0 0 0 k G
The initial range displayed is the same as the
latest probe range. To set an alarm in a different
range, push Select Range until the proper range displays. Then use the numeric keypad to enter the high
alarm point. After entering the desired high alarm point, press Enter to accept the new value or Escape to
retain the old value.
The display proceeds to the Low Alarm Point:
Low
A la r m P o in t
+ 0 .5 0 0 0 k G
The initial range displayed is the same as the
latest probe range. To set an alarm in a different
range, push Select Range until the proper range
displays. Then use the numeric keypad to enter the low alarm point. After entering the desired alarm point,
press Enter to accept the new value or Escape to retain the old value. The alarm setpoints are absolute
(unsigned), i.e., only the magnitude of the field reading is used.
After entering proper high and low alarm points, press Alarm On/Off to activate the alarm. The message
“Alarm On” appears on the lower line of the display, and the musical note appears in the upper right-hand
corner of the display, signifying alarm ON. When the field reading is outside the alarm setpoints, the musical
note flashes and, if turned ON, the alarm sounds. To turn the alarm OFF, press Alarm On/Off again. The
message “ Alarm Off” appears.
The example below details how the alarm operates on the Inside setting. Use the alarm inside setup to look
for good readings. For example, to check 1 kG magnets for a tolerance of ±0.25 kG, set the high alarm point
1.25 kG and the low alarm point to 0.75 kG. The diagram below illustrates when the alarm is ON or OFF.
Alarm
Off
–3 kG
–2 kG
Example of operation with
alarm triggered by
readings INSIDE user
defined setpoints.
3-8
Alarm
On
–1 kG
Alarm
Off
0 kG
Alarm
On
+1 kG
Alarm
Off
+2 kG
+3 kG
Low Alarm
Point
High Alarm Point
Operation
Lake Shore Model 450 Gaussmeter User’s Manual
To enter this alarm setup, push Alarm Set. The
unit prompts for the High Alarm Point:
H ig h
A la r m P o in t
+ 1 .2 5 0 0 k G
The initial range displayed is the same as the
latest probe range. To set an alarm in a different
range, push Select Range until the proper range displays. Then use the numeric keypad to enter the high
alarm point. After entering the desired high alarm point, press Enter to accept the new value or Escape to
retain the old value.
The display proceeds to the Low Alarm Point:
Low
A la r m P o in t
+ 0 .7 5 0 0 k G
The initial range displayed is the same as the
latest probe range. To set an alarm in a different
range, push Select Range until the proper range
displays. Then use the numeric keypad to enter the low alarm point. After entering the desired alarm point,
press Enter to accept the new value or Escape to retain the old value. The alarm setpoints are absolute
(unsigned) i.e., only the magnitude of the field reading is used.
After entering proper high and low alarm points, press Alarm On/Off to activate the alarm. The message
“Alarm On” appears on the lower line of the display the musical note appears in the upper right-hand corner of
the display, signifying alarm on. To turn the alarm off, again press the Alarm On/Off key. The message “
Alarm Off” appears. When the field reading is inside the alarm setpoints, the musical note flashes and, if
turned ON, the alarm sounds.
3.10 LOCAL AND ADDRESS
Normal front panel operation is called Local operation. However, the IEEE-488 Interface provides remote
operation. A Model 450 connected to a suitably equipped computer may either permit or inhibit front panel
operation. The Local key toggles between local (front panel functional) or remote (front panel disabled). The
letter “R” displays in the upper right side of the display to signify Remote mode activation.
Before using the IEEE-488 Interface, set the IEEE Address and Terminators. Press Address to display the
screen to the right. Press the ▲ or ▼ keys to
increment or decrement the IEEE Address to the
required number. Press Enter to accept the new
number or Escape to retain the existing number.
S e le c t W it h ¨ ©
IE E E A d d r e s s
12
The Model 450 automatically proceeds to the
IEEE-488 Terminator display. Press the ▲ or ▼
keys to cycle through the following IEEE-488
Terminator choices:
Cr Lf Carriage Return and Line Feed.
Lf Cr Line Feed and Carriage Return.
LF
Line Feed.
EOI
End Or Identify.
Terminators are fixed to Cr Lf for the Serial Interface.
S e le c t W it h
T e r m in a t o r s
¨©
Cr
Lf
3.11 BAUD
To use the Serial Interface, set the Baud rate.
Press Baud to display the screen to the right.
Press the ▲ or ▼ keys to cycle through the
choices of 300, 1200, or 9600 Baud. Press Enter
to accept the new number or Escape to keep the
existing setting and return to the normal display.
S e le c t W it h ¨ ©
Baud
3
¡ 12
96
3.12 ANALOG OUT
There are two rear panel analog outputs on the Model 450 called the Corrected and Monitor Analog Outputs.
Both use BNC connectors with the center conductor carrying the signal and the outer portion the ground.
Refer to Paragraph 3.12.1 for Corrected Analog Output and Paragraph 3.12 2 for Monitor Analog Output.
Operation
3-9
Lake Shore Model 450 Gaussmeter User’s Manual
3.12.1 Corrected Analog Out
The Corrected Analog Output is a DC value proportional to the displayed field. The displayed field reading
may be corrected for probe nonlinearity, zero offset, and temperature. This output is not a real time signal, but
updates at the same rate as the display.
The standard Model 450 has a Corrected output where ±3 volts equals ± full scale for the selected range.
The Model 450-10 features a modified Corrected Analog Output where ±10 volts equals ± full scale for the
selected range. The examples in this section assume the standard ±3 volt setting. For the example below, the
3 kG range was selected.
Display
Reading
–3 kG
–2 kG
–1 kG
Output
Voltage
–3 V
–2 V
–1 V
To select the default range, press the Analog Out
key to display the screen to the right. Press the
Analog Out, ▲, or ▼ key to cycle the arrow (→) to
Def (Default). Press Enter to set the Corrected
Analog Output for ±3V = ±3 kG.
0 kG
0V
+1 kG
+2 kG
+3 kG
+1 V
+2 V
+3 V
S e le c t W it h ¨ ©
A n a lo g O u t, ¡ D e f U s e r
The user may also change Corrected Analog Output scaling. User-defined scaling can improve resolution
over a selected area. For example, below is a symmetrical scaling similar to the default scale.
Display
Reading
Output
Voltage
–1.5 kG
–3 V
–1 kG
–0.5 kG
–2 V
–1 V
To enter this scale, press Analog Out. Press the
Analog Out, ▲, or ▼ key to cycle the arrow (→) to
User as shown.
Press Enter to display the Max Output screen.
0 kG
0V
+0.5 kG
+1 kG
+1.5 kG
+1 V
+2 V
+3 V
S e le c t W it h ¨ ©
A n a lo g O u t D e f ¡ U s e r
Enter the numbers 1.5 on the numerical keypad
and press Enter. The unit places a maximum
output of +1.5 kG into memory and displays the
Min Output screen.
E n te r
M a x O u tp u t
+ 1 .5 0 0 0 k G
Enter the numbers –1.5 on the numerical keypad
and press Enter. The unit places a minimum
output of –1.5 kG into memory. Changes to the
Corrected Analog Output are immediately
observable.
E n te r
M in O u t p u t
- 1.5 0 0 0 k G
The example below is an asymmetrical scaling which demonstrates the versatility of user-selectable scaling.
Display
Reading
Output
Voltage
0 kG
–3 V
+0.5 kG
+1 kG
–2 V
–1 V
To enter this scale, press Analog Out. Press the
Analog Out, ▲, or ▼ key to cycle the arrow (→) to
User as shown.
3-10
+1.5 kG
0V
+2 kG
+2.5 kG
+3 kG
+1 V
+2 V
+3 V
S e le c t W it h ¨ ©
A n a lo g O u t D e f ¡ U s e r
Operation
Lake Shore Model 450 Gaussmeter User’s Manual
Press Enter to display the Max Output screen.
Enter the number 3 on the numerical keypad and
press Enter. The unit places a maximum output
of +3.0 kG into memory and displays the Min
Output screen.
E n te r
M a x O u tp u t
+ 3 .0 0 0 0 k G
E n te r
M in O u t p u t
+ 0 .0 0 0 0 kG
Enter the numbers 0.0 on the numerical keypad
and press Enter. The unit places a minimum
output of 0.0 kG into memory. Changes to the
Corrected Analog Output are immediately observable.
For best results, put at least 100 counts between minimum and maximum for the range. For example, if the
3.0000 kG range was selected with a minimum scale of 1.0000 kG, enter a maximum setting of 1.0100 kG or
greater.
3.12.2 Monitor Analog Out
The Monitor Analog Output is a real-time analog signal proportional to the magnetic field and scaled to ±3
volts for full scale of selected range. It is not as accurate as the Corrected Monitor Output, but it has the full
400 Hz bandwidth of the AC measurement. Most of the error is on lower ranges and results from zero offsets
in the probe and instrument. The error can be minimized by subtracting output voltage observed at zero field
from the live output.
3.12.3 Analog Output Control Mode
It is sometimes convenient to use the corrected analog output as a control voltage output instead of an analog
output proportional to measured field. A set of computer interface commands control the digital-to-analog
converter (DAC) for the corrected analog output. One common application is using the output to program an
electromagnet power supply. By using the analog output, the user can avoid purchasing a magnet supply
controller and adding a separate interface to their computer.
The Model 450 software dated 10/1/94 and newer supports this feature. Update older Model 450 software at
no charge. The actual output voltage and voltage resolution depends on an instrument hardware setting. The
Model 450 comes with standard ±3 volt output or optional ±10 volt output. To upgrade from ±3 volt output to
±10 volt output, consult the factory.
Output Range:
±3 volts
±10 volts
Resolution:
0.37 mV 1.2 mV
Two commands control the corrected analog output via the IEEE-488 or Serial Interface. The ANOD command
specifies interface control of the output; set it to “2”. Send this command only once. The ANOD? query
confirms the change. This setting will not change if the instrument is powered off, but it can be changed back
to normal operation from the front panel.
The AOCON command sets bipolar output voltage in percent of full scale. The setting format of ±xxx.xx; allows
for a sign and a resolution of 0.01%. As a safety precaution, this setting always equals zero if the instrument
looses power or is turned off. The setting cannot be changed from the front panel. The AOCON? query
confirms the change. Example: Sending AOCON –50.25 sets output to –50.25% of full scale. This is
–5.025 V for a ±10 V output or –1.5075 V for a ±3 V output.
Operation
3-11
Lake Shore Model 450 Gaussmeter User’s Manual
3.13 LOCKING AND UNLOCKING THE KEYBOARD
The Model 450 front panel keyboard may be locked, preventing unauthorized changes to the settings. To lock
the keyboard, press and hold Enter (about 10 seconds) until the following display appears.
E n te r C o d e T o
Lock Keypad
Enter the 3-digit lock code (the default is 123). Upon entry of the third number, the display reverts to the
normal display. The keyboard is now locked. After locking the keypad, any attempt to change settings
displays the following *Locked* message.
* L o c ke d *
To unlock the keyboard, press and hold the Enter key until the following message is displayed.
E n te r C o d e T o
U n lo c k K e y p a d
Enter the lock code again. Upon entry of the third number, the display reverts to the normal display and the
keyboard is unlocked.
Change the lock code using either the IEEE-488 or RS-232C Computer Interface. For future reference, record
the lock code for your installation. If the instrument is reset (Paragraph 3.14), the lock code reverts to 123.
The instrument cannot be reset when the keyboard is locked.
3.14 FACTORY DEFAULT SETTINGS
With the keypad unlocked and the Model 450 in local mode, the user may press and hold Escape for about
20 seconds to return the instrument to factory default settings:
AC/DC: DC
Address: 12
Alarm: Off
Alarm Trigger: Outside
Analog Out: Default
Audible Alarm: On
Auto Range: Off
Baud: 300
Brightness: 4
Fast Data Mode: Off
Field Compensation: On
Filter: Off
Filter Number: 8
Filter Window %: 1%
Gauss/Tesla: Gauss
Keypad: Not Locked
Local/Remote: Local
Lock Code: 123
Max Hold: Off
Peak/RMS: RMS
Range: Highest Range For Probe
Relative: Off
Temperature Compensation: On
Terminators: CR/LF
Other gaussmeter calibration information and probe data are not affected by this reset. Zero the probe after
completing this operation.
3-12
Operation
Lake Shore Model 450 Gaussmeter User’s Manual
3.15 PROBE CONSIDERATIONS
To avoid damage and for best results during use, the probes have a number of handling and accuracy
requirements that must be observed. Changing probes is discussed in Paragraph 3.16.1. Probe
handling is discussed in Paragraph 3.16.2. Probe operation is discussed in Paragraph 3.16.3. Finally,
accuracy considerations are provided in Paragraph 3.16.4.
3.15.1 Changing Probes
A 512-byte Electrically Erasable Programmable Read Only Memory (EEPROM) is included in each
probe. The EEPROM stores specific information that the gaussmeter requires for operation. The
information includes serial number, probe sensitivity, and field compensation data.
CAUTION:
The probe must be connected to the rear of the instrument before applying
power to the gaussmeter. Probe memory may be erased if connected with
power on.
When the instrument is powered up, the probe memory is downloaded to the gaussmeter. This is how
the gaussmeter knows which ranges are available and which error correction to apply. To change
probes, first turn power off, remove the existing probe, and then plug in the new probe. When power
is restored, the characteristics of the new probe are downloaded to the gaussmeter memory. Normal
operation may continue after the new probe offset is nulled using the Zero Probe operation.
If the instrument is powered up with no probe attached, the following message is displayed.
* * NO PROBE * *
P o w e r o f f to a t ta c h !
3.15.2 Probe Handling
Although every attempt has been made to make the probes as sturdy as possible, the probes are still
fragile. This is especially true for the exposed sensor tip of some transverse probes. Care should be
taken during measurements that no pressure is placed on the tip of the probe. The probe should only
be held in place by securing at the handle. The probe stem should never have force applied. Any
strain on the sensor may alter the probe calibration, and excessive force may destroy the Hall
generator.
CAUTION:
Care must be exercised when handling the probe. The tip of the probe is very
fragile. Stressing the Hall sensor can alter its calibration. Any excess force can
easily break the sensor. Broken sensors are not repairable.
Avoid repeated flexing of the stem of a flexible probe. As a rule, the stem should not be bent more
than 45° from the base. See Figure 3-4. Force should never be applied to the tip of the probe. On all
probes, do not pinch or allow cables to be struck by any heavy or sharp objects. Although damaged
or severed cables should be returned to Lake Shore for repair, please understand that probes are not
always repairable.
When probes are installed on the gaussmeter but not in use, the protective tubes provided with many
probes should be placed over the probe handle and stem in order to protect the tip. When the
gaussmeter is not in use, the probes should be stored separately in some type of rigid container. The
cardboard and foam container that Lake Shore probes are shipped in may be retained for probe
storage. For further details on available accessories and probes, refer to Chapter 5.
Operation
3-13
Lake Shore Model 450 Gaussmeter User’s Manual
Do not bend from
tip of probe
45°
45°
Stem
Flexible Transverse Probe
Maximum Bend Angle
The tip is
VERY FRAGILE
C-421-3-4.eps
Figure 3-4. Maximum Flexible Probe Bend Radius
3.15.3 Probe Operation
In the DC mode of operation, the orientation of the probe affects the polarity reading of the
gaussmeter. On a transverse probe, the Lake Shore name printed on the handle indicates the side for
positive (+) flux entry. On an axial probe, positive (+) flux entry is always from the front of the probe.
See Figure 3-5.
NOTE: For best results, the instrument and probe should warm up for at least 5 minutes
before zeroing the probe, and at least 30 minutes for rated accuracy. The probe and
the zero gauss chamber should be at the same temperature.
If the exact direction of the magnetic field is unknown, the proper magnitude is determined by turning
on Max Hold and slowly adjusting the probe. As the probe turns and the measured field rises and
falls, its maximum value is held on the display. Make note of the probe orientation at the maximum
reading to identify the field orientation.
Lake Shore Logo
Towards North Pole
N
B
S
Transverse Probe Orientation
For Positive (+) Measurement
B
S
N
Axial Probe Orientation
For Positive (+) Measurement
C-421-3-5.eps
Figure 3-5. Probe Orientation For Positive Measurement
3-14
Operation
Lake Shore Model 450 Gaussmeter User’s Manual
3.15.4 Probe Accuracy Considerations
NOTE: Probe readings are dependent upon the angle of the sensor in relation to the
magnetic field. The farther from 90° the angle between the probe and the field, the
greater the percentage of error. For example, a 5° deviation causes a 0.4% error, a
10° deviation causes a 1.5% error, etc.
NOTE: For best results, the instrument and probe should warm up for at least 5 minutes
before zeroing the probe, and at least 30 minutes for rated accuracy. The probe and
the zero gauss chamber should be at the same temperature.
The user must consider all the possible contributors to the accuracy of the reading. Both the probe
and gaussmeter have accuracy specifications that may impact the actual reading. The probe should
be zeroed before making critical measurements. The zero probe function is used to null (cancel) out
the zero offset of the probe or small magnetic fields. It is normally used in conjunction with the zero
gauss chamber, but may also be used with an open probe (registering the local earth magnetic field).
Users wishing to cancel out large magnetic fields should use the Relative function. Refer to
Paragraph 3.8.
Probe temperature can also affect readings. Refer to the two separate temperature coefficients listed
on the specification sheet. The High Stability (HST) probes exhibit a low temperature coefficient of
gain due to the inherent thermal stability of the materials used in its construction.
Probe readings are dependent on the angle of the sensor (Hall sensor) in relation to the magnetic
field. Maximum output occurs when the flux vector is perpendicular to the plane of the sensor. This is
the condition that exists during factory calibration. The greater the deviation from orthogonality (from
right angles in either of three axes), the larger the error of the reading. For example, a 5° variance on
any one axis causes a 0.4% error, a 10° misalignment induces a 1.5% error, etc. See Figure 3-6.
Tolerance of instrument, probe, and magnet must be considered for making critical measurements.
The accuracy of the gaussmeter reading is better than ±0.20% of reading and ±0.05% of range.
Absolute accuracy readings for gaussmeters and Hall probes is a difficult specification to give,
because all the variables of the measurement are difficult to reproduce. For example, a 1° error in
alignment to the magnetic field causes a 0.015% reading error. Finally, the best probes have an
accuracy of ±0.15%. This implies that the absolute accuracy measurement of a magnetic field is not
going to reliably be better than ±0.15% under the best of circumstances, and more likely to be 0.20%
to 0.25%.
29.3%
45°
+B
13.4%
6.0%
3.4%
1.5%
0.4%
0%
Error
30°
20°
15°
10°
5°
0°
Deviation from
Perpendicular
(θ)
Effect of angular variations on
percentage of reading error
where % Error = (1 – cos θ) 100
Figure 3-6. Effect Of Angle On Measurements
Operation
C-421-3-6.eps
3-15
Lake Shore Model 450 Gaussmeter User’s Manual
3.16 FAST DATA MODE
In normal operation, the instrument updates the display, computer interfaces, and the corrected analog
output at a rate of 5 readings per second. Fast Data Mode increases the data rate when operating with
either the IEEE-488 or Serial Interface. While the corrected analog output update rate does correspond
to the Fast Data Mode, the front panel display will not operate in this mode. In Fast Data Mode, the
front panel screen displays the message below.
Fast
D a ta
Mode
To place the instrument in Fast Data Mode, use the interface command: FAST 1.
To leave fast data mode, use this command: FAST 0.
To query the status of Fast Data Mode, use this command: FAST? The unit returns 0 if Fast Data Mode
is Off, and 1 if On.
NOTE: Fast Data Mode activation disables the following Model 450 functions: Relative, Max Hold,
Alarms, and Autorange. Temperature compensation (if applicable) is based on the last
temperature reading prior to FAST DATA MODE activation. The temperature is not updated
during FAST DATA MODE.
Use the normal interface command to query field measurement data. Without display overhead, the
instrument can take 18 new readings each second. An efficiently written IEEE-488 program can return
all 18 readings without slowing the instrument down. When using the IEEE-488 Interface, never try to
read faster than 18 readings a second.
The additional overhead associated with Serial Communication slows instrument Serial Interface
communications to a maximum of 15 readings per second at 9600 Baud. When using the Serial
Interface, never try to read faster than 15 readings a second.
3-16
Operation
Lake Shore Model 450 Gaussmeter User’s Manual
CHAPTER 4
REMOTE OPERATION
4.0
GENERAL
Either of the two computer interfaces provided with the Model 450 permit remote operation. First is the
IEEE-488 Interface in Paragraph 4.1, and second is the Serial Interface in Paragraph 4.2. The two interfaces
share a common set of commands, provided in Paragraph 4.3. Use only one of the interfaces at a time.
4.1
IEEE-488 INTERFACE
The IEEE-488 Interface is an instrumentation bus with hardware and programming standards that simplify
instrument interfacing. The Model 450 IEEE-488 Interface complies with the IEEE-488.2-1987 standard and
incorporates its functional, electrical, and mechanical specifications unless otherwise specified in this manual.
All instruments on the interface bus perform one or more of the interface functions of TALKER, LISTENER, or
BUS CONTROLLER. A TALKER transmits data onto the bus to other devices. A LISTENER receives data
from other devices through the bus. The BUS CONTROLLER designates to the devices on the bus which
function to perform. The MPS performs the functions of TALKER and LISTENER but cannot be a BUS
CONTROLLER. The BUS CONTROLLER is the digital computer which tells the MPS which functions to
perform.
Below are Model 450 IEEE-488 interface capabilities:
• SH1 Source handshake capability.
• RL1 Complete remote/local capability.
• DC1 Full device clear capability.
• DT0 No device trigger capability.
No system controller capability.
• C0
• T5
Basic TALKER, serial poll capability, talk only, unaddressed to talk if addressed to listen.
• L4
Basic LISTENER, unaddressed to listen if addressed to talk.
• SR1 Service request capability.
• AH1 Acceptor handshake capability.
• PP0 No parallel poll capability.
• E1
Open-collector electronics.
4.1.1
Model 450 IEEE-488 Interface Settings
If using the IEEE-488 interface, set the IEEE
Address and Terminators. Press Address to
display the screen to the right. Press the ▲ or ▼
keys to increment or decrement the IEEE
Address to the desired number. Press Enter to
accept new number or Escape to retain the existing number. Pressing either Enter or Escape displays the
Terminators screen below.
S e le c t W it h ¨ ©
IE E E A d d r e s s
12
Press the ▲ or ▼ keys to cycle through the
following Terminator choices: CR/LF, LF/CR, LF,
and EOI. To accept changes or the currently
displayed setting, push Enter. To cancel
changes, push Escape. Power down the Model
450 then power it up again to allow other devices on the IEEE-488 bus to recognize a new Address or
Terminator setting.
S e le c t W it h
T e r m in a t o r s
Remote Operation
¨©
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4-1
Lake Shore Model 450 Gaussmeter User’s Manual
4.1.2
IEEE-488 Command Structure
The Model 450 supports several command types. These commands are divided into three groups.
1. Bus Control – Refer to Paragraph 4.1.2.1.
a. Universal
(1) Uniline
(2) Multiline
b. Addressed Bus Control
2. Common – Refer to Paragraph 4.1.2.2.
3. Interface and Device Specific – Refer to Paragraph 4.1.2.3.
4.1.2.1
Bus Control Commands
A Universal Command addresses all devices on the bus. Universal Commands include Uniline and Multiline
Commands. A Uniline Command (Message) asserts only a single signal line. The Model 450 recognizes two
of these messages from the BUS CONTROLLER: Remote (REN) and Interface Clear (IFC). The MPS sends
one Uniline Command: Service Request (SRQ).
REN (Remote) – Puts the Model 450 into remote mode.
IFC (Interface Clear) – Stops current operation on the bus.
SRQ (Service Request) – Tells the bus controller that the Model 450 needs interface service.
A Multiline Command asserts a group of signal lines. All devices equipped to implement such commands do
so simultaneously upon command transmission. These commands transmit with the Attention (ATN) line
asserted low. The Model 450 recognizes two Multiline commands:
LLO (Local Lockout) – Prevents the use of instrument front panel controls.
DCL (Device Clear) – Clears Model 450 interface activity and puts it into a bus idle state.
Finally, Addressed Bus Control Commands are Multiline commands that must include the Model 450 listen
address before the instrument responds. Only the addressed device responds to these commands. The
Model 450 recognizes three of the Addressed Bus Control Commands:
SDC (Selective Device Clear) – The SDC command performs essentially the same function as the DCL
command except that only the addressed device responds.
GTL (Go To Local) – The GTL command is used to remove instruments from the remote mode. With some
instruments, GTL also unlocks front panel controls if they were previously locked out with the LLO command.
SPE (Serial Poll Enable) and SPD (Serial Poll Disable) – Serial polling accesses the Service Request
(SRQ) Status Register. This status register contains important operational information from the unit
requesting service. The SPD command ends the polling sequence.
4.1.2.2
Common Commands
Common Commands are addressed commands which create commonalty between instruments on the bus.
All instruments that comply with the IEEE-488 1987 standard share these commands and their format.
Common commands all begin with an asterisk. They generally relate to “bus” and “instrument” status and
identification. Common query commands end with a question mark (?). Refer to Paragraph 4.3 for a list of all
Model 450 common commands.
4.1.2.3
Interface and Device Specific Commands
Device Specific Commands are addressed commands. The Model 450 supports a variety of Device Specific
commands to program instruments remotely from a digital computer and to transfer measurements to the
computer. Most Device Specific Commands perform functions also performed from the front panel. This
section discusses Common and Device Specific commands. Device Specific Commands consist of Interface,
Display, Channel, Control Process and Curve commands. Refer to Paragraph 4.3 for a list of all Model 450
interface and device specific commands.
4-2
Remote Operation
Lake Shore Model 450 Gaussmeter User’s Manual
4.1.3
Status Registers
There are two status registers: the Status Byte Register (Paragraph 4.1.3.1), and the Standard Event Status
Register (Paragraph 4.1.3.2).
4.1.3.1
Status Byte Register and Service Request Enable Register
The Status Byte Register consists of one data byte containing six bits of information about Model 450 status.
STATUS BYTE REGISTER FORMAT
Bit –
Weighting –
Bit Name –
7
128
Not Used
6
64
SRQ
5
32
ESB
4
16
OVI
3
8
Not Used
2
4
ALM
1
2
RNG
0
1
FDR
If the Service Request is enabled, setting any of these bits causes the Model 450 to pull the SRQ
management low to signal the BUS CONTROLLER. These bits reset to zero upon a serial poll of the Status
Byte Register. Inhibit or enable these reports by turning their corresponding bits off or on in the Service
Request Enable Register. The QSRE command sets the bits. Setting a bit in the Service Request Enable
Register, enables that function. Refer to the QSRE command.
Service Request (SRQ) Bit (6) – Determines whether the Model 450 reports via the SRQ line. Four bits
determine which status reports to make. If bits 0, 1, 2, 4, and/or 5 are set, then the corresponding bit in the
Status Byte Register is set. The Model 450 produces a service request only if bit 6 of the Service Request
Enable Register is set. If disabled, the BUS CONTROLLER still examines Status Byte Register status reports
by serial poll (SPE), but the Service Request cannot interrupt the BUS CONTROLLER. The QSTB common
command reads the Status Byte Register but will not clear the bits.
The Status Byte Register bit assignments are described below. These reports occur only if enabled in the
Service Request Enable Register.
Field Data Ready (FDR) Bit (0) – When set, new valid field readings are available.
Range Change (RNG) Bit (1) – Range changed in Auto Range mode on any channel.
Alarm (ALM) Bit (2) – When set, an alarm condition exists on any channel. This condition latches until
acknowledged by the bus controller.
Overload Indicator (OVI) Bit (4) – When set, indicates a display overload on any selected channel. Issues a
Service Request if enabled.
Standard Event Status (ESB) Bit (5) – When set, indicates if one of the bits from the Standard Event Status
Register has been set (Paragraph 4.1.4.2.).
4.1.3.2
Standard Event Status Register and Standard Event Status Enable Register
The Standard Event Status Register supplies various conditions of the Model 450.
STANDARD EVENT STATUS REGISTER FORMAT
Bit –
Weighting –
Bit Name –
7
128
PON
6
64
Not Used
5
32
CME
4
16
EXE
3
8
DDE
2
4
QYE
1
2
Not Used
0
1
OPC
Bits 2 and 6 are not used. Reports of this register interrupt the user only if the bits are enabled in the Standard
Event Status Enable Register and if bit 5 of the Service Request Enable Register is set.
The Standard Event Status Enable Register allows the user to enable any of the Standard Event Status
Register reports. The Standard Event Status Enable command (QESE) sets the Standard Event Status
Enable Register bits. Setting a bit of this register, enables that function. To set a bit, send the command QESE
with the sum of the bit weighting for each bit to be set. Refer to the QESE command.
The Standard Event Status Enable Query, QESE?, reads the Standard Event Status Enable Register. QESR?
reads the Standard Event Status Register. Once this register is read, the bits reset to zero.
Remote Operation
4-3
Lake Shore Model 450 Gaussmeter User’s Manual
Power On (PON) Bit (7) – Set to indicate a controller off-on-off transition.
Command Error (CME) Bit (5) – Set to indicate a command error since the last reading. Controller unable to
interpret a command due to syntax error, unrecognized header or terminators, or unsupported command.
Execution Error (EXE) Bit (4) – Set to indicate an execution error. This occurs when the controller is
instructed to do something not within its capabilities.
Device Dependent Error (DDE) Bit (3) – Set to indicate a device dependent error. Determine the actual
device dependent error by executing the various device dependent queries.
Query Error (QYE) Bit (2) – Set to indicate a query error. Occurs rarely, but involves data loss due to full
output queue.
Operation Complete (OPC) Bit (0) – This bit is generated in response to the QOPC common command. It
indicates when the Model 450 has completed all selected pending operations.
4.1.4
Example IEEE Setup and Program
Below is an example of how to setup and run a simple program using the built-in Model 450 IEEE-488
Interface. It does not reflect every hardware/software configuration found in the field. This example uses the
National Instruments GPIB - PCII/IIA card and QuickBasic 4.0 or 4.5 on a PC compatible.
4.1.4.1
GPIB Board Installation
1. Install GPIB-PCII/IIA card using National Instruments instructions.
2. Install NI - 488.2 software (for DOS). Version 2.1.1 was used for the example.
3. Verify that config.sys contains the command: device = \gpib-pc\gpib.com
4. Reboot the computer.
5. Run IBTEST to test software configuration. Do not install the instrument before running IBTEST.
6. Run IBCONF to configure the GPIB - PCII/IIA board and dev 12. Set the EOS byte to 0AH. See the setup
in Figure 4-1. IBCONF modifies gpib.com.
7. Connect the instrument to the interface board and power up the instrument. Verify address as 12 and
terminators as CR LF.
4.1.4.2
Running The Example QuickBasic Program
1. Copy c:\gpib-pc\Qbasic\qbib.obj to the QuickBasic directory (QB4).
2. Change to the QuickBasic directory and type: link /q qbib.obj,,,bqlb4x.lib; where x = 0 for QB4.0 and 5
for QB4.5 This one-time only command produces the library file qbib.qlb. The procedure is found in the
National Instruments QuickBasic readme file Readme.qb.
3. Start QuickBasic. Type: qb /l qbib.qlb. Start QuickBasic in this way each time the IEEE interface is used
to link in the library file.
4. Create the IEEE example interface program in QuickBasic. Refer to Table 4-1. Name the file
“ieeeexam.bas” and save.
5. Run the program.
4-4
Remote Operation
Lake Shore Model 450 Gaussmeter User’s Manual
4.1.5
Notes On Using the IEEE Interface
•
To chain commands or queries together, insert a semi-colon (;) between them. Multiple queries cannot be
chained. The Model 450 responds to the last query entered when addressed as a talker.
•
Queries generally use the same syntax as an associated setting command followed by a question mark.
They most often return the same information that is sent. Some queries have no command form.
•
Add a query to the end of a command string to confirm command execution. For example, CUNI K;CUNI?
commands the Model 450 to set the temperature units to kelvin then return the temperature units to
confirm the change.
•
The term free field indicates that the decimal point is a floating entity and can be placed at any appropriate
place in the string of digits.
•
Leading zeros and zeros following a decimal point are unneeded in a command string, but they are sent in
response to a query. A leading “+” is not required, but a leading “–” is required.
•
[term] indicates where the user places terminating characters or where they appear on a returning
character string from the Model 450.
Table 4-1. Sample BASIC IEEE-488 Interface Program
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IEEEEXAM.BAS
EXAMPLE PROGRAM FOR IEEE-488 INTERFACE
This program works with QuickBasic 4.0/4.5 on an IBM PC or compatible.
The example requires a properly configured National Instruments GPIB-PC2 card. The REM
$INCLUDE statement is necessary along with a correct path to the file QBDECL.BAS. CONFIG.SYS
must call GPIB.COM created by IBCONF.EXE prior to running Basic. There must be QBIB.QBL
library in the QuickBasic Directory and QuickBasic must start with a link to it. All
instrument settings are assumed to be defaults: Address 12, Terminators <CR> <LF> and EOI
active.
To use, type an instrument command or query at the prompt. The command transmits to the
instrument and the MPS receives and displays the response. If no query is sent, the
instrument responds to the last query received. Type "EXIT" to exit the program. NOTE: The
INPUT instruction accepts no commas as part of an input string. If a comma appears in an
instrument command, replace it with a space.
REM $INCLUDE: 'c:\gpib-pc\qbasic\qbdecl.bas'
CLS
PRINT "IEEE-488 COMMUNICATION PROGRAM"
PRINT
'Link to IEEE calls
'Clear screen
CALL IBFIND("dev12", DEV12%)
TERM$ = CHR$(13) + CHR$(10)
'Open communication at address 12
'Terminators are <CR><LF>
LOOP2: IN$ = SPACE$(2000)
'Clear for return string
INPUT "ENTER COMMAND (or EXIT):"; CMD$
CMD$ = UCASE$(CMD$)
IF CMD$ = "EXIT" THEN END
CMD$ = CMD$ + TERM$
'Get command from keyboard
'Change input to upper case
'Get out on Exit
CALL IBWRT(DEV12%, CMD$)
'Send command to instrument
CALL IBRD(DEV12%, IN$)
'Get data back each time
ENDTEST = INSTR(IN$, CHR$(13))
IF ENDTEST > 0 THEN
IN$ = MID$(IN$, 1, ENDTEST - 1)
PRINT "RESPONSE:", IN$
ELSE
PRINT "NO RESPONSE"
END IF
GOTO LOOP2
'Test for returned string
'String is present if <CR> is seen
'Strip off terminators
'Print return string
Remote Operation
'No string present if timeout
'Get next command
4-5
Lake Shore Model 450 Gaussmeter User’s Manual
National Instruments
GPIB0 configuration
Primary GPIB Address............ →0
Secondary GPIB Address.......NONE
Timeout setting .......................10sec
↑ Select the primary GPIB address by
using the left and right arrow keys.
This address is used to compute the
talk and listen addresses which
identify the board or device on the
GPIB. Valid primary addresses range
from 0 to 30 (00H to 1EH).
Terminate Read on EOS ........Yes
Set EOI with EOS on Writes ...Yes
Type of compare on EOS .......7-Bit
EOS byte ................................0Ah
Send EOI at end of Write........Yes
* Adding 32 to the primary address
forms the Listen Address (LA).
* Adding 64 to the primary address
forms the Talk Address (TA).
System Controller ...................Yes
Assert REN whe SC ...............No
Enable Auto Serial Polling ......No
Enable CIC Protocol ...............No
Bus Timing..............................500nsec
Parallel Poll Duration ..............Default
EXAMPLE: Selecting a primary address
of 10 yields the following:
Use this GPIB board ...............Yes
Board Type .............................PCII
Base I\O Address....................02B8h
F1: Help
F6: Reset Value
National Instruments
10 + 32 = 42
10 + 64 = 74
↓
F9/Esc: Return to Map
DEV12 Configuration
Primary GPIB Address............ →12
Secondary GPIB Address.......NONE
Timeout setting .......................10sec
GPIB-PC2/2A Ver 2.1
(Listen address)
(Talk address)
Ctl PgUp/PgDn: Next/Prev Board
GPIB-PC2/2A Ver 2.1
↑ Select the primary GPIB address by
using the left and right arrow keys.
This address is used to compute the
talk and listen addresses which
identify the board or device on the
GPIB. Valid primary addresses range
from 0 to 30 (00H to 1EH).
Terminate Read on EOS ........Yes
Set EOI with EOS on Writes ...Yes
Type of compare on EOS .......7-Bit
EOS byte ................................0Ah
Send EOI at end of Write........Yes
* Adding 32 to the primary address
forms the Listen Address (LA).
* Adding 64 to the primary address
forms the Talk Address (TA).
Enable Repeat Addressing .....Yes
EXAMPLE: Selecting a primary address
of 10 yields the following:
10 + 32 = 42
10 + 64 = 74
(Listen address)
(Talk address)
↓
F1: Help
F6: Reset Value
F9/Esc: Return to Map
Ctl PgUp/PgDn: Next/Prev Board
Figure 4-1. Typical National Instruments GPIB Configuration from IBCONF.EXE
4-6
Remote Operation
Lake Shore Model 450 Gaussmeter User’s Manual
4.2
SERIAL I/O INTERFACE
RS-232C is a standard of the Electronics Industries Association (EIA) and one of the most common interfaces
between a computer and electronic equipment. The Customer supplied computer must have a Serial Interface
port. The Model 450 Serial Interface complies with the electrical format of the RS-232C Interface Standard.
A Serial Interface between the computer and the Model 450 permits remote monitoring and control of
Model 450 control functions, which in turn controls Model 450 operation. See Figure 4-2.
The Serial Interface can both transmit and receive information. In transmit (Tx) mode, the instrument converts
parallel information to serial and sends it over a cable up to 50 feet long (or longer with proper shielding). In
receive (Rx) mode, the instrument converts serial information back to parallel for processing.
Refer to Paragraph 4.2.1 for Serial Interface hardware configuration and adapters, Paragraph 4.2.2 for Serial
Interface settings, and Paragraph 4.2.3 for a sample BASIC program to establish communications between
the computer and the Model 450.
The Serial Interface shares Device Specific commands with the IEEE-488 interface listed in Paragraph 4.3.
However, without the advantage of the IEEE-488 Architecture, there are several limitations:
• No Bus Control Commands apply.
• Only QIDN? and QRST Common Commands are usable.
• Terminators are fixed to CRLF.
• A query must be added to the end of a command string if the Model 450 must return information. (Over
IEEE-488, the last query response is sent when addressed to talk). For example: “UNIT G;UNIT?” sets the
units to gauss and immediately queries unit status.
To Customer Supplied Computer
DB-25 Serial Interface Connector
LSCI Model 4002 RJ-11
to DB-25 Adapter
SERIAL I/O
RS-232C
Interface Output
on rear of Model
450
Use whichever adapter that
matches your computer
serial interface connector
To Customer Supplied
Computer DE-9 Serial
Interface Connector
LSCI Model 4003 RJ-11
to DE-9 Adapter
LSCI Model 4001 RJ-11
Cable Assembly
C-450-U-4-2
Figure 4-2. Serial Interface Adapters
Remote Operation
4-7
Lake Shore Model 450 Gaussmeter User’s Manual
4.2.1
Serial Interface Hardware Configuration
Below is a technical description of the Serial Interface. Table 4-2 lists communication parameters.
Terminators are fixed to Carriage Return (CR) and Line Feed (LF).
The connector used for the serial interface is a standard 6-wire RJ-11 (telephone) jack. Lake Shore offers the
Model 4001 10-foot Cable Assembly, Model 4002 RJ-11 to DB-25 Adapter, and the Model 4003 RJ-11 to
DE-9 Adapter. Refer to Chapter 5 for Serial I/O connector and adapter pin out details, and Chapter 6 for
adapter dimensional data.
Table 4-2. Serial Interface Specifications
Transmission
Connector
Timing Format
Transmission Mode
Baud Rate
Bits per Character
Parity Type
Data Interface Levels
Fixed Terminator
4.2.2
Three-Wire
RJ-11 Modular Socket
Asynchronous, RS-232C Electrical Format
Half Duplex
300, 1200, or 9600
1 Start, 7 Data, 1 Parity, and 1 Stop
Odd
Transmits and Receives Using EIA Voltage Levels
CR (0DH) LF (0AH)
Serial Interface Settings
To use the Serial Interface, set the Baud rate. Press
Baud to display the screen to the right. Press the ▲ or
▼ keys to cycle through the choices of 300, 1200, or
9600 Baud. Press Enter to accept the new number or
Escape to keep the existing setting and return to the
normal display.
4.2.3
S e le c t W it h ¨ ©
Baud
3
¡ 12
96
Sample BASIC Serial Interface Program
The program in Table 4-4 is a sample interactive serial poll routine for the Model 450 Serial Interface written
in QuickBASIC V4.0. The following are typical examples using this BASIC program. Input provided by the
user is shown in bold type.
ENTER COMMAND? FIELD?
+000.12
ENTER COMMAND? RANGE?
Field Reading Query. Unit returns field reading in the form ±XXX.XX.
Decimal point placement appropriate to range.
Range Query. Unit returns appropriate range: 0 = highest range
through 3 = lowest range.
0
ENTER COMMAND? UNITS?
Units Query. Unit returns appropriate units: G = gauss, T = tesla.
G
ENTER COMMAND? ACDC?
AC or DC Query. Unit returns appropriate setting: 0 = DC, 1 = AC.
0
ENTER COMMAND? FILT?
Filter Query. Unit returns appropriate setting: 0 = Off, 1 = On.
0
ENTER COMMAND? FILT 1;FILT?
Unit turns the filter On, then returns a 1 to verify the change.
1
ENTER COMMAND?
4-8
Remote Operation
Lake Shore Model 450 Gaussmeter User’s Manual
4.2.4
•
•
•
•
•
•
•
•
•
Notes On Using The Serial Interface
To chain commands together, insert a semi-colon (;) between them. Multiple queries cannot be chained.
Queries generally use the same syntax as the associated setting command followed by a question mark. They usually
return the same information that is sent.
Add a query to the end of a command string to confirm command execution. For example, UNIT G;UNIT? commands
the Model 450 to set units to gauss then requests the Model 450 return the units to confirm the change.
A correctly spelled query without a "?", returns nothing. Misspelled commands and queries are ignored.
The term free field indicates a decimal point floats and can be placed at any appropriate place in the string of digits.
Leading zeros and zeros following a decimal point are unneeded in a command string, but they are sent in response to
a query. A leading “+” is not required, but a leading “–” is required.
[term] indicates where the user places terminating characters or where they appear on a returning character string
from the Model 450.
The following commands are available only over the computer interface; there are no front panel equivalent
commands: CODE, BRIGT, FAST, and SNUM.
To change number inputs to the field reading resolution, first set them to zero.
Table 4-3. Sample BASIC Serial Interface Program
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SEREXAM.BAS - EXAMPLE PROGRAM FOR SERIAL INTERFACE
This program works with QuickBasic 4.0/4.5 or Qbasic on an IBM PC or compatible
with a serial interface. It uses the COM1 communication port at 9600 BAUD. Enter
an instrument command or query at the prompt. The command transmits to the
instrument which displays any query response. Type "EXIT" to exit the program.
NOTE: The INPUT instruction in this example accepts no commas as part of an input
string. If a comma appears in an instrument command, replace it with a space.
CLS
'Clear screen
PRINT " SERIAL COMMUNICATION PROGRAM"
PRINT
TIMEOUT = 2000
'Read timeout (may need more)
BAUD$ = "9600"
TERM$ = CHR$(13) + CHR$(10)
'Terminators are <CR><LF>
OPEN "COM1:" + BAUD$ + ",O,7,1,RS" FOR RANDOM AS #1 LEN = 256
LOOP1: INPUT "ENTER COMMAND (or EXIT):"; CMD$
CMD$ = UCASE$(CMD$)
IF CMD$ = "EXIT" THEN CLOSE #1: END
CMD$ = CMD$ + TERM$
PRINT #1, CMD$;
IF INSTR(CMD$, "?") <> 0 THEN
RS$ = ""
N = 0
'Get command from keyboard
'Change input to upper case
'Get out on Exit
'Send command to instrument
'Test for query
'If query, read response
'Clr return string and count
WHILE (N < TIMEOUT) AND (INSTR(RS$, TERM$) = 0) 'Wait for response
IN$ = INPUT$(LOC(1), #1)
'Get one character at a time
IF IN$ = "" THEN N = N + 1 ELSE N = 0 'Add 1 to timeout if no chr
RS$ = RS$ + IN$
'Add next chr to string
WEND
'Get chrs until terminators
IF RS$ <> "" THEN
'See if return string is empty
RS$ = MID$(RS$, 1, (INSTR(RS$, TERM$) - 1)) 'Strip off terminators
PRINT "RESPONSE:"; RS$
'Print response to query
ELSE
PRINT "NO RESPONSE"
'No response to query
END IF
END IF
'Get next command
GOTO LOOP1
Remote Operation
4-9
Lake Shore Model 450 Gaussmeter User’s Manual
4.3
IEEE-488/SERIAL INTERFACE COMMAND SUMMARY
There are four command groups: Common Commands (Paragraph 4.3.2), Interface Commands (Paragraph
4.3.3), Device Specific Commands (Paragraph 4.3.4), and Probe Commands (Paragraph 4.3.5).
Command
Function
Common Commands
*CLS
*ESE
*ESE?
*ESR?
*IDN?
*OPC
*OPC?
*RST
*SRE
*SRE?
*STB?
*TST?
*WAI
Page
Command
ANOLM?
AOCON
AOCON?
AUTO
AUTO?
BRIGT
BRIGT?
CODE
CODE?
FAST
FAST?
FIELD?
FIELDM?
FILT
FILT?
FNUM
FNUM?
FWIN
FWIN?
LOCK
LOCK?
MAX
MAX?
MAXC
MAXR?
MAXRM?
PRMS
PRMS?
RANGE
RANGE?
REL
REL?
RELR?
RELRM?
RELS
RELS?
RELSM?
UNIT
UNIT?
Clear Interface........................................ 4-11
Set Std. Event Status Enable ................. 4-11
Query Std. Event Status Enable............. 4-11
Query Std. Event Status Register........... 4-11
Query Identification ................................ 4-11
Set Operation Complete......................... 4-11
Query Operation Complete .................... 4-11
Reset Instrument.................................... 4-12
Set Service Request Enable .................. 4-12
Query Service Request Enable .............. 4-12
Query Status Byte .................................. 4-12
Query Self-Test ...................................... 4-12
Wait-To-Continue ................................... 4-12
Interface Commands
ADDR
ADDR?
BAUD
BAUD?
END
END?
MODE
MODE?
TERM
TERM?
Set Address ........................................... 4-13
Address Query ....................................... 4-13
Set Serial Interface Baud Rate ............... 4-13
Serial Interface Baud Rate Query........... 4-13
EOI......................................................... 4-13
EOI Query .............................................. 4-13
Remote Mode......................................... 4-13
Remote Mode Query .............................. 4-13
Terminator.............................................. 4-14
Terminator Query ................................... 4-14
Device Specific Commands
ACDC
ACDC?
ALARM
ALARM?
ALMB
ALMB?
ALMH
ALMH?
ALMHM?
ALMIO
ALMIO?
ALML
ALML?
ALMLM?
ALMS?
ANOD
ANOD?
ANOH
ANOH?
ANOHM?
ANOL
ANOL?
4.3.1
Set AC/DC Field Reading Status............ 4-14
AC/DC Field Reading Query .................. 4-14
Set Alarm Function On/Off ..................... 4-14
Alarm Query ........................................... 4-14
Set Audible Alarm Status ....................... 4-15
Audible Alarm Query .............................. 4-15
Set Alarm High Point .............................. 4-15
Alarm High Point Query.......................... 4-15
Alarm High Point Multiplier Query .......... 4-15
Set Alarm Trigger Inside/Outside ........... 4-15
Alarm Trigger Inside/Outside Query ....... 4-15
Set Alarm Low Point............................... 4-15
Alarm Low Point Query .......................... 4-15
Alarm Low Point Multiplier Query ........... 4-16
Alarm Status Query................................ 4-16
Define Analog Out Default...................... 4-16
Analog Out Default Query ...................... 4-16
Define Analog Out High Setpoint............ 4-16
Analog Out High Setpoint Query ............ 4-16
Analog Out High Setpoint Multiplier........ 4-16
Define Analog Out Low Setpoint ............ 4-16
Analog Out Low Setpoint Query ............. 4-16
Command
List Structure
Function
Analog Out Low Setpoint Multiplier......... 4-17
Analog Output Control Mode .................. 4-17
Analog Output Control Mode Query ....... 4-17
Set Autorange Status On/Off.................. 4-17
Autorange On/Off Query ........................ 4-17
Set Display Brightness Status ................ 4-17
Display Brightness Query ....................... 4-17
Set Keyboard Lock Code ....................... 4-17
Keyboard Lock Code Query ................... 4-18
Set Fast Data Mode ............................... 4-18
Fast Data Model Status Query ............... 4-18
Present Field Reading Query ................. 4-18
Present Field Multiplier Query ................ 4-18
Set Display Filter Status ......................... 4-18
Display Filter Query................................ 4-18
Set Filter Points...................................... 4-18
Filter Points Query.................................. 4-19
Set Filter Window ................................... 4-19
Filter Window Query............................... 4-19
Set Keyboard Lock Status ...................... 4-19
Keyboard Lock Query............................. 4-19
Set Max Hold Status............................... 4-19
Max Hold Query ..................................... 4-19
Initiate Max Clear (Reset)....................... 4-19
Max Reading Query ............................... 4-19
Max Reading Multiplier Query ................ 4-20
Set Peak/RMS AC Field Status .............. 4-20
Peak/RMS AC Field Reading Query....... 4-20
Set Manual Range Status....................... 4-20
Manual Range Query ............................. 4-20
Set Relative Mode Status ....................... 4-20
Relative Mode Query.............................. 4-20
Relative Mode Reading Query ............... 4-20
Relative Mode Reading Multiplier ........... 4-21
Set Relative Mode Setpoint .................... 4-21
Relative Mode Setpoint Query................ 4-21
Relative Mode Setpoint Multiplier ........... 4-21
Set gauss or tesla Units ......................... 4-21
Gauss or tesla Units Query .................... 4-21
Probe Commands
FCOMP
FCOMP?
SNUM?
TCOMP
TCOMP?
TYPE?
ZCAL
Set Field Compensation Status .............. 4-22
Field Compensation Status Query.......... 4-22
Probe Serial Number Query ................... 4-22
Set Temp Compensation Status............. 4-22
Temp Compensation Status Query ........ 4-22
Probe Type Query .................................. 4-22
Initiate Zero Probe Command ................ 4-22
Command Name
Brief Description of Function
RANGE?
Syntax of what user must input.
Information returned in response
to the query.
Explanation and definition of
returned data.
4-10
Page
Input:
Returned:
Remarks:
Manual Reading Query
RANGE?
0, 1, 2, or 3
Used to query the unit for manual range. Range
is dependent on type of probe installed. There
are four ranges possible for each probe, where 0
is the highest and 3 is the lowest range.
Remote Operation
Lake Shore Model 450 Gaussmeter User’s Manual
4.3.2
Common Commands
Clear Interface Command
Input:
*CLS
Returned: Nothing
Remarks: Clears the bits in the Status Byte Register and Standard Event Status Register and
terminates all pending operations. Clears the interface, but not the controller. The controller
related command is *RST.
QCLS
Configure Status Reports in the Standard Event Status Register
Input:
*ESE <bit weighting>
Returned: Nothing
Remarks: Each bit is assigned a bit weighting and represents the enable/disable status of the
corresponding event flag bit in the Standard Event Status Register. To enable an event flag
bit, send the command *ESE with the sum of the bit weighting for each desired bit. See the
*ESR? command for a list of event flags.
Example: To enable event flags 0, 3, 4, and 7, send the command *ESE 143[term]. 143 is the sum of
the bit weighting for each bit.
QESE
Bit
0
3
4
7
Bit Weighting
1
8
16
128
143
Event Name
OPC
DDE
EXE
PON
Query the Configuration of Status Reports in the Standard Event Status Register
Input:
*ESE?
Returned: <ESE bit weighting>. Format: nnn[term]
Remarks: The integer returned represents the sum of the bit weighting of the enable bits in the
Standard Event Status Enable Register.
QESE?
Query Standard Event Status Register
Input:
*ESR?
Returned: <ESR bit weighting>. Format: nnn[term]
Remarks: Queries for various Model 450 error conditions and status. The integer returned represents
the sum of the bit weighting of the event flag bits in the Standard Event Status Register.
QESR?
Query Identification
Input:
*IDN?
Returned: <manufacturer>, <model number>, <serial number>, <firmware date>
Format: LSCI,MODEL450,a,nnnnnn[term]
Remarks: Identifies the instrument model and software level.
QIDN?
Operation Complete Command
Input:
*OPC
Returned: Nothing
Remarks: Generates an Operation Complete event in the Event Status Register upon completion of all
pending selected device operations. Send it as the last command in a command string.
QOPC
Query Operation Complete
Input:
*OPC?
Returned: 1. Format: n[term]
Remarks: Places a “1” in the controller output queue upon completion of all pending selected device
operations. Send as the last command in a command string. Not the same as *OPC.
QOPC?
Remote Operation
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Lake Shore Model 450 Gaussmeter User’s Manual
Reset Instrument
Input:
*RST
Returned: Nothing
Remarks: Sets controller parameters to power-up settings.
QRST
Configure Status Reports in the Service Request Enable Register
Input:
*SRE <bit weighting>
Returned: Nothing
Remarks: Each bit has a bit weighting and represents the enable/disable status of the corresponding
status flag bit in the Status Byte Register. To enable a status flag bit, send the command
*SRE with the sum of the bit weighting for each desired bit. See the *STB? command for a
list of status flags.
Example: To enable status flags 0, 3, 4, and 6, send the command *SRE 89[term]. 89 is the sum of the
bit weighting for each bit.
QSRE
Bit
0
3
4
6
Bit Weighting
1
8
16
64
89
Event Name
New A&B
Alarm
Error
SRQ
Query the Configuration of Status Reports in the Service Request Enable Register
Input:
*SRE?
Returned: <SRE bit weighting>. Format: nnn[term]
Remarks: The integer returned represents the sum of the bit weighting of the enabled bits in the Service
Request Enable Register. See the *STB? command for a list of status flags.
QSRE?
QSTB?
Input:
Returned:
Remarks:
Query Status Byte
*STB?
<STB bit weighting>. Format: nnn[term]
Acts like a serial poll, but does not reset the register to all zeros. The integer returned
represents the sum of the bit weighting of the status flag bits that are set in the Status
Byte Register.
Query Self-Test
Input:
*TST?
Returned: 0 or 1. Format: n[term]
Remarks: The Model 330 performs a self-test at power-up. 0 = no errors found, 1 = errors found.
QTST?
Wait-to-Continue
Input:
*WAI
Returned: Nothing
Remarks: Prevents execution of any further commands or queries until completion of all previous ones.
Changing the sample sensor and reading it immediately with a device dependent query may
result in a reading error because the sensor needs time to stabilize. Place a *WAI between
the sensor change and query for a correct reading. Achieve the same results with repeated
queries or using a Service Request, but *WAI is easier.
QWAI
Send *WAI as the last command in a command string followed by appropriate termination. It
cannot be embedded between other commands.
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Remote Operation
Lake Shore Model 450 Gaussmeter User’s Manual
4.3.3 INTERFACE COMMANDS
ADDR
Set IEEE Address.
Input:
[address]:
Returned:
Remarks:
ADDR?
ADDR [address]
An integer from 1 to 30. Address 0 and 31 are reserved.
Nothing
Sets the IEEE address. The Model 450 is factory preset to 12.
IEEE Address Query.
Input:
ADDR?
Returned: 1 to 30.
Remarks: Returns the current IEEE address setting. The Model 450 is factory preset to 12.
BAUD
Set Serial Interface Baud Rate.
Input:
[type]:
BAUD 0, BAUD 1, or BAUD 2
There are three settings for the type parameter: 0 = 300 Baud
1 = 1200 Baud
2 = 9600 Baud
Returned: Nothing
Remarks: Sets the Serial Interface Baud rate.
BAUD?
Serial Interface Baud Rate Query.
Input:
BAUD?
Returned: Returns current Serial Baud rate, where: 0 = 300 Baud, 1 = 1200 Baud, and 2 = 9600 Baud
END
Set End Or Identify (EOI) Status.
Input:
END 0 or END 1
Returned: Nothing
Remarks: Sets the EOI status: 0 = enabled, 1 = disabled. When enabled, the hardware EOI line
becomes active with the last byte of a transfer. The EOI identifies the last byte allowing for
variable length data transmissions.
END?
End Or Identify (EOI) Status Query.
Input:
Returned:
MODE
END?
Current EOI status: 0 = EOI enabled, 1 = EOI disabled.
Set Local, Remote, or Remote With Local Lockout Mode.
Input:
MODE 0, MODE 1, or MODE 2
Returned: Nothing
Remarks: Sets the Model 330 mode: 0 = Local Mode, 1 = Remote Mode, 2 = Remote Mode with Local
Lockout. Press the front panel Local key to set the Model 330 to local provided the key has
not been disabled by local lockout. The Model 330 powers up in local mode.
Example: At the end of a command string, MODE 0 maintains constant local operation.
MODE?
Mode Query.
Input:
MODE?
Returned: Current mode setting: 0 = local mode, 1 = remote mode, 2 = remote mode with local lockout.
Remote Operation
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Lake Shore Model 450 Gaussmeter User’s Manual
TERM
Set Terminating Character Type.
Input:
TERM 0, TERM 1, TERM 2, or TERM 3
Returned: Nothing
Remarks: Sets the terminating character type from 0 to 3 defined as follows:
0 = Carriage return and line feed (CR)(LFEOI)
1 = Line feed and carriage return (LF)(CREOI)
2 = Line feed (LFEOI)
3 = No terminating characters – EOI line set with last data byte if enabled (End)
Terminating characters are sent when the Model 330 completes its message transfer on
output. They also identify the end of an input message. This command works only with the
IEEE-488 Interface and does not change the serial terminators.
TERM?
Terminator Query.
Input:
TERM?
Returned: Returns the current terminating character type:
0 = Carriage return and line feed (CR)(LFEOI)
1 = Line feed and carriage return (LF)(CREOI)
2 = Line feed (LFEOI)
3 = No terminating characters – EOI line set with last data byte if enabled (End)
Remarks: This command works only with the IEEE-488 Interface.
4.3.4
Device Specific Commands
ACDC
Set AC or DC Magnetic Field Reading Status.
Input:
ACDC 0 or ACDC 1
Returned: Nothing
Remarks: Configures the unit for AC or DC measurements: 0 = DC, 1 = AC. The AC field is further
defined by the PRMS (Peak or RMS) command.
ACDC?
AC or DC Magnetic Field Reading Query.
Input:
ACDC?
Returned: 0 or 1
Remarks: Queries current AC or DC measurement status: 0 = DC, 1 = AC. The AC field is further
defined by the PRMS (Peak or RMS) command.
ALARM
Set Alarm Function On/Off.
Input:
ALARM 0 or ALARM 1
Returned: Nothing
Remarks: Sets the alarm function: 0 = Off, 1 = On.
ALARM?
Alarm Query.
Input:
ALARM?
Returned: 0 or 1
Remarks: Queries unit for alarm function: 0 = Off, 1 = On.
4-14
Remote Operation
Lake Shore Model 450 Gaussmeter User’s Manual
ALMB
Set Audible Alarm Status.
Input:
ALMB 0 or ALMB 1
Returned: Nothing
Remarks: Sets the audible alarm status: 0 = Off, 1 = On.
ALMB?
Audible Alarm Query.
Input:
ALMB?
Returned: 0 or 1
Remarks: Queries current audible alarm status: 0 = Off, 1 = On.
ALMH
Set Alarm High Point.
Input:
ALMH XXX.XX
Returned: Nothing
Remarks: Enter up to 5 digits with decimal point. No sign required. Place decimal appropriate to range.
ALMH?
Alarm High Point Query.
Input:
ALMH?
Returned: XXX.XX
Remarks: Returns up to 5 digits with decimal point. Places decimal appropriate to range.
ALMHM?
Alarm High Point Multiplier Query.
Input:
ALMHM?
Returned: u, m, k, or _
Remarks: Queries alarm high point multiplier: u = micro (x 1/1,000,000), m = milli (x 1/1,000),
k = kilo (x 1,000), and _ (Blank) = unity (x 1).
ALMIO
Set Alarm Trigger Inside/Outside Status.
Input:
ALMIO 0 or ALMIO 1
Returned: Nothing
Remarks: Sets alarm trigger inside/outside status: 0 = Outside, 1 = Inside. This setting determines
whether readings inside or outside the defined magnetic field range trigger the alarm.
ALMIO?
Alarm Trigger Inside/Outside Query.
Input:
ALMIO?
Returned: 0 or 1
Remarks: Queries alarm trigger inside/outside status: 0 = Outside, 1 = Inside. This setting determines
whether readings inside or outside the defined magnetic field range trigger the alarm.
ALML
Set Alarm Low Point.
Input:
ALML XXX.XX
Returned: Nothing
Remarks: Enter up to 5 digits with decimal point. No sign required. Place decimal appropriate to range.
ALML?
Alarm Low Point Query.
Input:
ALML?
Returned: XXX.XX
Remarks: Returns up to 5 digits with decimal point. Places decimal appropriate to range.
Remote Operation
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Lake Shore Model 450 Gaussmeter User’s Manual
ALMLM?
Alarm Low Point Multiplier Query.
Input:
ALMLM?
Returned: u, m, k, or _
Remarks: Queries alarm low point multiplier: u = micro (x 1/1,000,000), m = milli (x 1/1,000),
k = kilo (x 1,000), and _ (Blank) = unity (x 1).
ALMS?
Alarm Status Query.
Input:
ALMS?
Returned: 0 or 1
Remarks: Queries current alarm status: 0 = Off, 1 = On. Off means no alarm condition exists; On
means an alarm exists.
ANOD
Set Default Analog Out Status.
Input:
ANOD 0, ANOD 1, or ANOD 2
Returned: Nothing
Remarks: Sets default analog output status: 0 = Off, 1 = On, 2 = analog output controlled by remote
interface (see AOCON).
ANOD?
Default Analog Out Query.
Input:
ANOD?
Returned: 0, 1, or 2
Remarks: Queries default analog output status: 0 = Off, 1 = On, 2 = analog output controlled by remote
interface (see AOCON).
ANOH
Define Analog Out High Setpoint.
Input:
ANOH ±XXX.XX
Returned: Nothing
Remarks: Enter sign, up to 5 digits, and decimal point. Place decimal appropriate to range.
ANOH?
Analog Out High Setpoint Query.
Input:
ANOH?
Returned: ±XXX.XX
Remarks: Returns sign, up to five digits, and decimal point. Places decimal appropriate to range.
ANOHM?
Analog Out High Setpoint Multiplier Query.
Input:
ANOHM?
Returned: u, m, k, or _
Remarks: Queries analog out high setpoint multiplier: u = micro (x 1/1,000,000), m = milli (x 1/1,000), k
= kilo (x 1,000), and _ (Blank) = unity (x 1).
ANOL
Define Analog Out Low Setpoint.
Input:
ANOL ±XXX.XX
Returned: Nothing
Remarks: Enter sign, up to 5 digits, and decimal point. Place decimal appropriate to range.
ANOL?
Analog Out Low Setpoint Query.
Input:
ANOL?
Returned: ±XXX.XX
Remarks: Returns sign, up to five digits, and decimal point. Places decimal appropriate to range.
4-16
Remote Operation
Lake Shore Model 450 Gaussmeter User’s Manual
ANOLM?
Analog Out Low Setpoint Multiplier Query.
Input:
ANOLM?
Returned: u, m, k, or _
Remarks: Queries analog out low setpoint multiplier: u = micro (x 1/1,000,000), m = milli (x 1/1,000), k =
kilo (x 1,000), and _ (Blank) = unity (x 1).
AOCON
Set Analog Output Control Mode.
Input:
AOCON ±XXX.XX
Returned: Nothing
Remarks: Sets bipolar output voltage in percent of full scale. Allows a resolution of 0.01%. As a safety
precaution, this setting always equals zero if the instrument loses power or is turned off. The
setting cannot be changed from the front panel. Refer to Paragraph 4.5.
Example: The command AOCON –50.25 sets output to –50.25% of full scale. This is –5.025 volts for a
±10 volt output or –1.5075 volts for a ±3 volt output.
AOCON?
Analog Output Control Mode Query.
Input:
AOCON?
Returned: ±XXX.XX
Remarks: Queries the unit for the current analog output control mode percentage of full scale reading.
The setting format of ±xxx.xx allows a sign and resolution of 0.01%. As a safety precaution,
this setting always equals zero if the instrument loses power or is turned off. The setting
cannot be changed from the front panel. Refer to Paragraph 4.5.
AUTO
Set Auto Range Status.
Input:
AUTO 0 or AUTO 1
Returned: Nothing
Remarks: Sets the Auto Range status: 0 = Auto Range Off, 1 = Auto Range On.
AUTO?
Auto Range Query.
Input:
AUTO?
Returned: 0 or 1
Remarks: Queries Auto Range status: 0 = Off, 1 = On.
BRIGT
Set Front Panel Display Brightness.
Input:
BRIGT 0 thru 7
Returned: Nothing
Remarks: Sets front panel display brightness: 0 = lowest through 7 = highest. Default = 4.
BRIGT?
Front Panel Display Brightness Query.
Input:
BRIGT?
Returned: 0 thru 7
Remarks: Returns a single digit corresponding to the current display brightness setting: 0 = lowest
through 7 = highest. Default = 4.
CODE
Set Front Panel Keyboard Lock Code.
Input:
CODE XXX
Returned: Nothing
Remarks: Sets front panel keyboard lock code: Default = 123. Enter any three numbers.
Remote Operation
4-17
Lake Shore Model 450 Gaussmeter User’s Manual
CODE?
Front Panel Keyboard Lock Code Query.
Input:
CODE?
Returned: XXX
Remarks: Returns the 3 numbers that comprise the front panel keyboard lock code.
FAST
Set Fast Data Mode.
Input:
FAST 0 or FAST 1
Returned: Nothing
Remarks: Sets Fast Data Mode which obtains data rates up to 18 readings per second via IEEE-488 or
15 readings per second via Serial Interface with a corresponding increase in corrected analog
output. The front panel display does not function in this mode. Refer to Paragraph 3.16.
FAST?
Fast Data Mode Status Query.
Input:
FAST?
Returned: 0 or 1
Remarks: Queries Fast Data Mode status: 0 = Off, 1 = On. Obtains data rates up to 18 readings per
second via IEEE-488 or 15 readings per second via the Serial Interface with a corresponding
increase in corrected analog output. The front panel display does not function in this mode.
Refer to Paragraph 3.16.
FIELD?
Present Magnetic Field Reading.
Input:
FIELD?
Returned: ±XXX.XX
Remarks: Returns sign, six numbers if the filter is on, five numbers if the filter is off, and decimal point.
Places decimal appropriate to range. Requires MULT? and UNITS? commands to fully define
the reading.
FIELDM?
Field Reading Multiplier Query.
Input:
FIELDM?
Returned: u, m, k, or _
Remarks: Queries field reading multiplier: u = micro (x 1/1,000,000), m = milli (x 1/1,000),
k = kilo (x 1,000), and _ (Blank) = unity (x 1).
FILT
Set Display Filter Status.
Input:
FILT 0 or FILT 1
Returned: Nothing
Remarks: Turns display filter On or Off: 0 = Off, 1 = On. Quiets the display reading by a degree
depending on the points (FNUM) and window (FWIN) settings. Refer to Paragraph 3.6.1.
FILT?
Display Filter Query.
Input:
FILT?
Returned: 0 or 1
Remarks: Queries display filter status: 0 = Off, 1 = On. Quiets the display reading by a degree
depending on the points (FNUM) and window (FWIN) settings. Refer to Paragraph 3.6.1.
FNUM
Set Display Filter Points.
Input:
FNUM XX
Returned: Nothing
Remarks: Sets filter points: XX = 2 thru 64. Numbers 2 thru 8 produce a linear filter response. Numbers
9 thru 64 produce an exponential filter response. In general, the higher the number, the
longer the display settle time. Refer to Paragraph 3.6.1.
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Remote Operation
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FNUM?
Display Filter Points Query.
Input:
FNUM?
Returned: XX
Remarks: Queries filter points setting: XX = 2 thru 64. Numbers 2 thru 8 produce a linear filter response.
Numbers 9 thru 64 produce an exponential filter response. In general, the higher the number,
the longer the display settle time. Refer to Paragraph 3.6.1.
FWIN
Set Display Filter Points.
Input:
FWIN XX
Returned: Nothing
Remarks: Sets the filter window: XX = 1% thru 10%. The smaller the percentage, the smaller the
change in magnetic field that causes the filter to restart. Refer to Paragraph 3.6.1.
FWIN?
Display Filter Points Query.
Input:
FWIN?
Returned: XX
Remarks: Queries filter window setting: XX = 1% thru 10%. The smaller the percentage, the smaller the
change in magnetic field that causes the filter to restart. Refer to Paragraph 3.6.1.
LOCK
Set Front Panel Keyboard Lock Status.
Input:
LOCK 0 or LOCK 1
Returned: Nothing
Remarks: Sets front panel keyboard lock status: 0 = Unlocked, 1 = Locked.
LOCK?
Front Panel Keyboard Lock Query.
Input:
LOCK?
Returned: 0 or 1
Remarks: Queries front panel keyboard lock status: 0 = Unlocked, 1 = Locked.
MAX
Set Max Hold Status.
Input:
MAX 0 or MAX 1
Returned: Nothing
Remarks: Sets the Max Hold feature: 0 = Off, 1 = On. Works with the MAXR and MAXC commands.
MAX?
Max Hold Query.
Input:
MAX?
Returned: 0 or 1
Remarks: Queries Max Hold status: 0 = Off, 1 = On. Works with the MAXR and MAXC commands.
MAXC
Initiate Max Clear (Reset).
Input:
MAXC
Returned: Nothing
Remarks: Initiate a Max Clear (or reset). Upon entry, Max Hold zeros out and captures a new peak.
MAXR?
Max Reading Query.
Input:
MAXR?
Returned: +XXX.XX
Remarks: Queries Max Hold reading. Returns the plus sign (+), five digits, and decimal point. Places
decimal appropriate to range.
Remote Operation
4-19
Lake Shore Model 450 Gaussmeter User’s Manual
MAXRM?
Max Reading Multiplier Query.
Input:
MAXRM?
Returned: u, m, k, or _
Remarks: Queries maximum reading multiplier: u = micro (x 1/1,000,000), m = milli (x 1/1,000),
k = kilo (x 1,000), and _ (Blank) = unity (x 1).
PRMS
Set Peak or RMS Magnetic Field Reading Status.
Input:
PRMS 0 or PRMS 1
Returned: Nothing
Remarks: Configures unit for RMS or Peak measurements: 0 = RMS, 1 = Peak. RMS or Peak is
selected after ACDC is set to AC.
PRMS?
Peak or RMS Magnetic Field Reading Query.
Input:
PRMS?
Returned: 0 or 1
Remarks: Queries Peak or RMS measurement status: 0 = RMS or 1 = Peak. RMS or Peak is selected
after ACDC is set to AC.
RANGE
Set Manual Range Status.
Input:
RANGE X
Returned: Nothing
Remarks: Range depends on type of probe installed. There are four ranges possible for each probe:
0 = highest through 3 = lowest. Refer to Paragraph 3.4.
RANGE?
Manual Range Query.
Input:
RANGE?
Returned: 0, 1, 2, or 3
Remarks: Queries manual range. Range depends on type of probe installed. There are four ranges
possible for each probe: 0 = highest through 3 = lowest. Refer to Paragraph 3.4.
REL
Set Relative Mode Status.
Input:
REL 0 or REL 1
Returned: Nothing
Remarks: Sets Relative Mode Status: 0 = Off, 1 = On.
REL?
Relative Mode Query.
Input:
REL?
Returned: 0 or 1
Remarks: Queries Relative Mode status: 0 = Off, 1 = On.
RELR?
Relative Mode Reading Query.
Input:
RELR?
Returned: ±XXX.XX
Remarks: Returns sign, up to 5 digits, and decimal point. Places decimal appropriate to range.
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Remote Operation
Lake Shore Model 450 Gaussmeter User’s Manual
RELRM?
Relative Mode Reading Multiplier Query.
Input:
RELRM?
Returned: u, m, k, or _
Remarks: Queries relative reading multiplier: u = micro (x 1/1,000,000), m = milli (x 1/1,000),
k = kilo (x 1,000), and _ (Blank) = unity (x 1).
RELS
Set Relative Mode Setpoint.
Input:
RELS ±XXX.XX
Returned: Nothing
Remarks: Enter sign, up to 5 digits, and decimal point. Place decimal appropriate to range.
RELS?
Relative Mode Setpoint Query.
Input:
RELS?
Returned: ±XXX.XX
Remarks: Returns sign, up to 5 digits, and decimal point. Places decimal appropriate to range.
RELSM?
Relative Mode Setpoint Multiplier Query.
Input:
RELSM?
Returned: u, m, k, or _
Remarks: Queries relative setpoint multiplier: u = micro (x 1/1,000,000), m = milli (x 1/1,000),
k = kilo (x 1,000), and _ (Blank) = unity (x 1).
UNIT
Set Gauss or Tesla Unit Status.
Input:
UNIT G or UNIT T
Returned: Nothing
Remarks: Sets unit status: G = gauss, T = tesla.
UNIT?
Gauss or Tesla Unit Query.
Input:
UNIT?
Returned: G or T
Remarks: Queries unit status: G = gauss, T = tesla.
Remote Operation
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Lake Shore Model 450 Gaussmeter User’s Manual
4.3.5
Probe Specific Commands
FCOMP
Set Field Compensation Status.
Input:
FCOMP 0 or FCOMP 1
Returned: Nothing
Remarks: Turns set field compensation On or Off: 0 = Off, 1 = On. If Off, probe field compensation
table, if present, is ignored.
FCOMP?
Field Compensation Query.
Input:
FCOMP?
Returned: 0 or 1
Remarks: Queries field compensation status: 0 = Off, 1 = On. If Off, probe field compensation table, if
present, is ignored.
SNUM?
Probe Serial Number Query.
Input:
SNUM?
Returned: XXXXXXXXXX
Remarks: Queries probe serial number. The latest probe serial number format is HXXXXX, though
there is room for up to a ten-character response.
TCOMP
Set Temperature Compensation Status.
Input:
TCOMP 0 or TCOMP 1
Returned: Nothing
Remarks: Turns set temperature compensation On or Off: 0 = Off, 1 = On. If off, probe temperature
compensation, if present, is ignored.
TCOMP?
Temperature Compensation Query.
Input:
TCOMP?
Returned: 0 or 1
Remarks: Queries temperature compensation status: 0 = Off, 1 = On. If off, probe temperature
compensation, if present, is ignored.
TYPE?
Probe Type Query.
Input:
TYPE?
Returned: 0, 1, or 2
Remarks: Queries probe type: 0 = high sensitivity, 1 = high stability, 2 = ultra-high sensitivity.
ZCAL
Initiate Zero Probe Command.
Input:
ZCAL
Returned: Nothing
Remarks: Initiates zero probe function. Place probe in the Zero Gauss Chamber first and then enter the
ZCAL command.
4-22
Remote Operation
Lake Shore Model 450 Gaussmeter User’s Manual
CHAPTER 5
ACCESSORIES AND PROBES
5.0
GENERAL
This chapter provides information on the accessories and probes available for the Model 450
Gaussmeter. Model numbers are detailed in Paragraph 5.1; accessories in Paragraph 5.2, Lake Shore
standard probes in Paragraph 5.3, Helmholtz coils in Paragraph 5.4, and reference magnets in
Paragraph 5.5.
5.1
MODELS
The list of Model 450 Model numbers is provided as follows.
Model
5.2
Description
450
Standard Model 450 Gaussmeter. Features ±3 volt corrected analog output.
450-10
Optional Model 450 Gaussmeter. Features ±10 volt corrected analog output.
ACCESSORIES
Accessories are devices that perform a secondary duty as an aid or refinement to the primary unit.
MODEL
NUMBER
DESCRIPTION
4001
RJ-11 Cable Assembly. Four-Wire Cable Assembly with RJ-11 plugs on each end. Used
with RS-232C Interface. Cable is 4.3 meters (14 feet) long. See Figure 5-11.
4002
RJ-11 to DB-25 Adapter. Adapts RJ-11 receptacle to female DB-25 connector. Connects
Model 450 to RS-232C Serial Port on rear of Customer’s computer. See Figure 5-12.
4003
RJ-11 to DE-9 Adapter. Adapts RJ-11 receptacle to female DE-9 connector. Connects
Model 450 to RS-232C Serial Port on rear of Customer’s computer. See Figure 5-13.
4004
IEEE-488 Interface Cable. Connects Model 450 to customer-supplied computer with
IEEE-488 Interface. Cable is 1 meter (3.3 feet) long.
4022
Half-Rack Mounting Kit for One 1/2 Rack Gaussmeter. Half-length mounting panel and
mounting ears to attach one Model 450 Gaussmeter to a 482.6 mm (19-inch) rack mount
space. See Figure 5-14.
4026
Dual Mounting Shelf for Two 1/2 Rack Gaussmeters. Mounting panel and mounting
ears to attach two Model 450 Gaussmeters to a 482.6 mm (19-inch) rack mount space.
See Figure 5-15.
4060
Standard Zero Gauss Chamber. Calibrates standard probes. Size: 32.2 × 32.2 × 61 mm
(1.27 × 1.27 × 2.4 in.). Bore: 12.2 mm dia. × 50.8 mm deep (0.48 × 2 in.). See Figure 5-9.
4065
Large Zero Gauss Chamber. Calibrates Gamma Probes™. Size: 57.1 × 53.3 × 304.8
mm (2.25 × 2.06 × 12 in.). Bore: 19.1 mm dia. × 279.4 mm deep (0.75 × 11 in.). See
Figure 5-10.
4502
Model 450 Gaussmeter User’s Manual.
MCBL-6
Hall Generator Cable Assembly. The MCBL-6 Cable Assembly connects a discrete Hall
generator to the Model 450 Gaussmeter. Cable is 2 meters (79 inches) long. The cable
ships with the HALLCAL.EXE program on a 3.5 inch diskette which permits cable PROM
programming through an IBM PC or compatible computer serial port. Because of the
many calibration intricacies, the user is responsible for measurement accuracy. Refer to
Appendix C.
Accessories and Probes
5-1
Lake Shore Model 450 Gaussmeter User’s Manual
Accessories (Continued)
MODEL
NUMBER
MH-XX
DESCRIPTION OF ACCESSORY
Helmholtz Coils. Provides stable low magnetic field when used with customer-supplied
power supply. Often used to provide reference field to help check gaussmeter accuracy.
Three coils are available as follows. Refer to Paragraph 5.3.
MH-2.5
Helmholtz Coil, 2.5-inch inner diameter, field strength: ≈30 G @ 1 A,
maximum continuous current: 2 A, coil resistance: ≈3 Ω. See Figure 5-5.
MH-6
Helmholtz Coil, 6-inch inner diameter, field strength: ≈25 G @ 1 A,
maximum continuous current: 2 A, Coil Resistance: ≈10 Ω. See Figure 5-6.
MH-12
Helmholtz Coil. 12-inch inner diameter, field strength: ≈12 G @ 1 A,
maximum continuous current: 2 A, Coil Resistance: ≈20 Ω. See Figure 5-7.
MRA-XXX
MRT-XXX
Reference Magnets. High-quality reference magnets are available in transverse (flat) and
axial (round) configurations. Refer to Paragraph 5.4 and see Figure 5-8.
MRA-312-100 Axial Reference Magnet: 0.312 inch inside diameter, 100 G, 1%
MRA-312-200 Axial Reference Magnet: 0.312 inch inside diameter, 200 G, 1%
MRA-312-300 Axial Reference Magnet: 0.312 inch inside diameter, 300 G, 1%
MRA-312-500 Axial Reference Magnet: 0.312 inch inside diameter, 500 G, 1%
MRA-312-1K Axial Reference Magnet: 0.312 inch inside diameter, 1 kG, 1%
MRA-312-2K Axial Reference Magnet: 0.312 inch inside diameter, 2 kG, 1%
MRT-062-200 Transverse Reference Magnet: 0.062 inch gap, 200 G, 1%
MRT-062-500 Transverse Reference Magnet: 0.062 inch gap, 500 G, 1%
MRT-062-1K Transverse Reference Magnet: 0.062 inch gap, 1 kG, 0.5%
MRT-062-2K Transverse Reference Magnet: 0.062 inch gap, 2 kG, 0.5%
MRT-062-5K Transverse Reference Magnet: 0.062 inch gap, 5 kG, 0.5%
MRT-062-10K Transverse Reference Magnet: 0.062 inch gap, 10 kG, 5%
MRT-343-50
Transverse Reference Magnet: 0.343 inch gap, 50 G, 1%
MRT-343-100 Transverse Reference Magnet: 0.343 inch gap, 100 G, 1%
MPEC-XXX
Probe Extension Cables. Four cables are available. Each extension cable contains a
EEPROM for calibration data. Each extension cable must be matched to a specific probe.
To maintain probe accuracy, that probe and extension cable must be calibrated together
at Lake Shore. The probe will exhibit its full accuracy if used without the extension cable.
Part numbers and cables lengths are defined as follows:
MPEC-10
Probe Extension Cable – 3 meters (10 feet)
MPEC-25
Probe Extension Cable – 7.6 meters (25 feet)
MPEC-50
Probe Extension Cable – 15.2 meters (50 feet)
MPEC-100 Probe Extension Cable – 30.5 meters (100 feet)
5-2
Accessories and Probes
Lake Shore Model 450 Gaussmeter User’s Manual
5.3
LAKE SHORE STANDARD PROBES
There are several types of Lake Shore Model 450 probes available: Transverse, Axial, Flexible
Transverse, and Gamma—each named by its Hall sensor orientation. Because the Model 450 covers
such a wide magnetic field range (0.01 mG to 300 kG), three probe ranges are available: High Stability
(HST), High Sensitivity (HSE), and Ultra-High Sensitivity (UHS). Please consult the factory for
availability of probe types not detailed in this section. Information on Hall generators is presented in
Appendix C of this manual.
5.3.1
Probe Selection Criteria
Some guidelines are provided below to aid in the selection of a probe for you application.
1. Choose a probe to match the application. Do not buy more accuracy, field range, or fragility than
is actually necessary.
2. The thinner a probe, the more fragile it is. Try to avoid the temptation to select an easily damaged
probe based on a possible, but not probable, future application. For instance, avoid using an
exposed-device probe such as a Model MFT-3E03 type for general field measurements. Once a
stem or sensor has been damaged, the probe is not repairable.
3. Metal enclosed probes, such as the Model MMT-6J08 and MMA-2508 types, offer the greatest
amount of protection to the Hall sensor, and therefore are the most rugged types.
4. Be cautious about using aluminum stemmed, transverse probes, such as the Model MMT-6J08
type, where AC magnetic fields are to be measured. Eddy currents in the stem material can affect
reading accuracy. A superior choice for AC measurements would b the Model MNT-4E04 type
fiberglass-epoxy stem probes.
5. Several stem lengths are offered for each probe type. User preferences or test set-up dimensions
usually determine the final selection. Longer stems are more susceptible to accidental bending
(in many cases not catastrophic, but bothersome). Stem length does not affect performance.
6. Be aware of the differences in the probe “active areas” shown on the data sheet. A Hall effect
probe will indicate the average field value sensed over that total active area. Thus, when
measuring magnetic fields with a high gradient across the sensor width, choose the smallest
active area practical (keeping in mind, however, the fragility rule in number 2 above).
7. Lake Shore gaussmeter probes exhibit different ranges of magnetic fields over which they will
provide valid readings. Check the specification sheet for these usable ranges. High Stability
probes, such as those whose model numbers end in -VG, are usable on full scale ranges of
300 gauss (30 millitesla) to 30 kilogauss (3 tesla). The High Sensitivity family of probes
(i.e., -VH models) can be used on 30 G (3 mT) to 30 kG (3 T) full scale ranges. High field probes
are specially calibrated to provide use above 30 kG (3 T), and the Gamma Probe operates on the
300 mG (30 µT) and 3 G (300 µT) ranges.
8. If none of the standard probe configurations seem to fit your needs, always remember that Lake
Shore can provide custom probes to meet your physical, temperature, and accuracy
requirements. Contact Lake Shore with details of your special requirements.
5.3.2
Radiation Effects on Gaussmeter Probes
The HST and HSE probes use a highly doped indium arsenide active material. The HST material is
the more highly doped of the two and therefore will be less affected by radiation. Some general
information relating to highly doped indium arsenide Hall generators is as follows:
•
•
•
•
Gamma radiation seems to have little effect on the Hall generators.
Proton radiation up to 10 Mrad causes sensitivity changes <0.5%.
15
Neutron cumulative radiation (>0.1 MeV, 10 /sq. cm.) can cause a 3 to 5% decrease in sensitivity.
In all cases the radiation effects seem to saturate and diminish with length of time exposed.
Accessories and Probes
5-3
Lake Shore Model 450 Gaussmeter User’s Manual
5.3.3
Probe Specifications
Terminology used in Figures 5-1 thru 5-4 are defined as follows:
A
+B
HST
HSE
UHS
Definition of Probe Terminology
Distance from tip of probe to center line of active area
Magnetic flux density vector (for positive gaussmeter reading)
High Stability Probe
High Sensitivity Probe
Ultra-High Sensitivity Probe
=
=
=
=
=
Usable Full-Scale Ranges Versus Probe Type
HST-1
HST-2
HSE-1
UHS-1
300 G
300 G
30 G
300 mG
3 kG
3 kG
300 G
3G
30 kG
30 kG
3 kG
30 G
300 kG
—
30 kG
—
Type
Usable on
Ranges
TRANSVERSE
+B
L
2.5"
A
W
Model No.
L
MMT-6J02-VH
2" ±0.125
MMT-6J04-VH 4" ±0.125
MMT-6J08-VH
8" ±0.125
T
T
0.36 ±0.030" dia.
Cable length = 6.6 feet
W
A
Active
Area
0.061" 0.180
max. ±0.005"
Stem
Material
Freq.
Range
Alum.
DC
HSE-1
MMT-6J18-VH 18" ±0.125
2" ±0.125 0.045" 0.150
MNT-4E04-VH 4" ±0.125 max. ±0.005" 0.150
±
MMT-6J02-VG 2" ±0.125
0.050"
MMT-6J04-VG 4" ±0.125 0.061" 0.180
MMT-6J08-VG 8" ±0.125 max. ±0.005"
MNT-4E02-VH
0.040"
dia.
approx.
Rigid
Glass
Epoxy
DC,
10 to
400 Hz
Alum.
DC
MMT-6J18-VG 18" ±0.125
Rigid
Glass
Epoxy
MNT-4E02-VG 2" ±0.125
0.045" 0.150
MNT-4E04-VG 4" ±0.125 max. ±0.005"
MCT-3160-WN
60" ±0.05
0.25" dia.
±0.010
Type
0.210"
±0.050
Stainless
Steel
DC,
10 to
400 Hz
Corrected
Accuracy
(% of rdg)
Op.
Temp.
Range
±0.25%
to
30 kG
Temperature
Coefficient (Max.)
Zero
Calibration
±0.09
Gauss
per °C
–0.015%
per °C
0 °C
to
+75 °C
HST-2
±0.15%
to
30 kG
HST-1
±2% to
100 kG
±0.13
Gauss
per °C
1.5 K to
350 K
–0.005%
per °C
–0.010%
per °C
C450-5-1.eps
Figure 5-1 Definition of Lake Shore Transverse Probes
5-4
Accessories and Probes
Lake Shore Model 450 Gaussmeter User’s Manual
AXIAL
2.5"
L
A
+B
Cable Length = 6.6 feet
Model
L
MMA-0602-TH
2 ±0.125"
MMA-0604-TH
4 ±0.125"
MMA-0608-TH
8 ±0.125"
MMA-0618-TH
18 ±0.125"
MMA-1302-UH
2 ±0.125"
MMA-1304-UH
4 ±0.125"
MMA-1308-UH
8 ±0.125"
MNA-1902-VH
2 ±0.125"
MNA-1904-VH
4 ±0.125"
MNA-1908-VH
8 ±0.125"
MMA-1802-VH
2 ±0.063"
MMA-1808-VH
8 ±0.125"
MMA-1818-VH
18 ±0.25"
MMA-1836-VH
36 ±0.25"
MMA-2502-VH
2 ±0.063"
MMA-2508-VH
8 ±0.125"
MNA-1902-VG
2 ±0.125"
MNA-1904-VG
4 ±0.125"
MNA-1908-VG
8 ±0.125"
MMA-1802-VH
2 ±0.063"
MMA-1808-VH
8 ±0.125"
MMA-1818-VH
18 ±0.25"
MMA-1836-VH
36 ±0.25"
MMA-2502-VG
2 ±0.063"
MMA-2508-VG
8 ±0.125"
MMA-1808-WL
MMA-2536-WL
MCA-2560-WN
D
A
0.060
dia.
+0.001
-0.003"
0.005
±
0.003"
0.125" 0.010
±
dia.
0.005"
±0.005"
Active
Area
0.020"
dia.
approx.
Freq.
Range
Type
Op.
Corrected
Accuracy Temp.
(% Reading) Range
±0.25%
to
10 kG
HST-2
±0.25%
to
20 kG
Stainless
Steel
Temp. Coefficient (Max.)
Zero
Calibration
±0.13 G
per °C
±0.010%
per °C
±0.09 G
per °C
–0.015%
per °C
±0.13 G
per °C
±0.005%
per °C
Fiberglass
Epoxy
DC,
10 to
400 Hz
0.060
dia.
+0.001
-0.003"
HSE-1
±0.25%
to
30 kG
HST-2
0.15%
to
30 kG
0 °C
to
75 °C
Alum.
0.030"
dia.
approx.
0.25 dia.
±0.006"
0.180
dia.
+0.002
–0.004"
Stem
Material
Alum.
0.187
0.005
dia.
±
±0.005" 0.003"
0.187
dia.
±0.005"
D
0.36 ±0.030" dia.
0.010
±
0.005"
0.25 dia.
±0.006"
0.180 dia.
+0.002
–0.004"
0.25 dia.
36 ±0.25"
±0.006"
0.25 dia. 0.025
60 ±0.50"
±0.005" ±0.005"
Fiberglass
Epoxy
Alum.
8 ±0.125"
HST-1
Stainless
Steel
DC
±1% to
100 kG
±2% to
100 kG
1.5 K to
350 K
±0.010%
per °C
C450-5-2.eps
Figure 5-2 Definition of Lake Shore Axial Probes
Accessories and Probes
5-5
Lake Shore Model 450 Gaussmeter User’s Manual
FLEXIBLE TRANSVERSE
+B
L
2.5"
S
A
W
0.125 ±0.020"
Cable Length = 6.6 feet
0.36 ±0.030" dia.
T
This table is for L = 3 inches and S = 0.375 inch
Model No.
MFT-3E03-VH
MFT-3E03-VG
MFT-2903-VJ
MFT-2903-VH
W
T
A
Active
Area
Stem Frequency
Material
Range
0.040"
0.135" 0.025" 0.125"
dia.
max max ±0.005" approx.
Flexible
Tubing
DC, 10 to
400 Hz
0.030"
0.085" 0.020" 0.065"
dia.
max max ±0.005" approx.
Type
Corrected
Accuracy
(% of
Reading)
HSE-1
±0.25% to
30 kG
HST-2
±0.15% to
30 kG
HSE-1
±0.50% to
30 kG
HST-2
±0.25% to
30 kG
Type
Corrected
Accuracy
(% of
Reading)
Temperature Coefficient
(maximum)
Operating
Temperature
Range
0 °C to
75 °C
Zero
Calibration
±0.09 G/°C
–0.015%/°C
±0.13 G/°C
±0.005%/°C
±0.09 G/°C
–0.015%/°C
±0.13 G/°C
±0.005%/°C
This table is for L = 15 inches and S = 0.75 inch
Model No.
MFT-4F15-VH
MFT-4F15-VG
W
T
A
Active
Area
Stem
Material
Flexible
0.040" Tubing
0.150" 0.045" 0.150"
dia.
max
max ±0.050" approx. & Epoxy
Fiberglass
Frequency
Range
DC, 10 to
400 Hz
HSE-1
±0.25% to
30 kG
HST-2
±0.15% to
30 kG
Temperature Coefficient
(maximum)
Operating
Temperature
Range
0 °C to
75 °C
Figure 5-3 Definition of Lake Shore Flexible Transverse Probes
5-6
Zero
Calibration
±0.09 G/°C
–0.015%/°C
±0.13 G/°C
±0.005%/°C
C450-5-3.eps
Accessories and Probes
Lake Shore Model 450 Gaussmeter User’s Manual
GAMMA PROBE
L
T
+B
Active Sensing Length
3.125"
Cable Length =
6.6 feet
Model No.
A
To Center of
Active Volume
W
T
A
L
W
Small variations in, or low values of large
volume magnetic fields, such as that of the
Earth or fringe fields, around large solenoids,
can be measured with these ultra-high
sensitivity probes. Resolutions of several
gammas (10– 5 gauss) to tens of gammas are
available depending on the mating
gaussmeter.
Application is optimum when fields are
homogeneous over lengths greater than
1 foot. The active sensing length of the
gamma probe is 3.125 inches.
Corrected
Temperature Coefficient
Accuracy Operating
(maximum)
Frequency Type
Temperature
(% of
Range
Range
Zero
Calibration
Reading)
±0.5% to
MLA-5006-HJ 0.25" 0.5" 2.2" 5.7" DC, 10 to UHS-1
2 gauss
400 Hz
0 °C to
75 °C
1 mG/°C
–0.05%/°C
C450-5-4.eps
Figure 5-4 Definition of Lake Shore Gamma Probe
Accessories and Probes
™
5-7
Lake Shore Model 450 Gaussmeter User’s Manual
5.4
HELMHOLTZ COILS
Lake Shore offers three Helmholtz coils: 2.5-, 6-, and 12-inch diameter. Check the latest Lake Shore
brochures or our website for any recent additions to this line.
These coils are accurately calibrated using field standards maintained at Lake Shore. Most standards
are traceable to physical standards such as a coil of carefully controlled dimensions, or in some cases,
to proton resonance. The field strengths are measured on the basis of the field generated by a current
through the coil.
When combined with a customer-supplied power supply, these coils can be used as low-field reference
magnets to compliment our set of standard reference magnets (defined in Paragraph 5.5). The power
supply must be capable of 2 A output and a constant-current mode is recommended.
Inside Diameter
Field Strength
Field Homogeneity
Coil Resistance
MH-2.5
2.5 inches
MH-6
6 inches
MH-12
12 inches
≈30 G @ 1 A
≈25 G @ 1 A
≈12 G @ 1 A
0.5% within a
cylindrical volume
0.75" long, 0.75"
diameter, located at
center of coil
0.5% within a
cylindrical volume
1.6" long, 1.6"
diameter, located at
center of coil
0.5% within a
cylindrical volume
3.2" long, 3.2"
diameter, located at
center of coil
≈3 Ω
≈10 Ω
≈20 Ω
Maximum Continuous Current
2A
Operating Temperature Range
10 to 40 °C (50 to 104 °F)
P-450-5-5.bmp
Figure 5-5. Model MH-2.5 Helmholtz Coil
5-8
Accessories and Probes
Lake Shore Model 450 Gaussmeter User’s Manual
P-450-5-6.bmp
Figure 5-6. Model MH-6 Helmholtz Coil
P-450-5-7.bmp
Figure 5-7. Model MH-12 Helmholtz Coil
Accessories and Probes
5-9
Lake Shore Model 450 Gaussmeter User’s Manual
5.5
REFERENCE MAGNETS
Magnetic reference standards containing highly stable permanent magnets have been in use for many
years. The highest quality units are usually shielded from external magnetic effects and use Alnico V or
VI magnets for long-term stability. They are supplied in both transverse (flat) and axial configurations.
Typical transverse reference magnets are usually stabilized for use at ambient temperatures between
0 – 50 °C and have nominal temperature coefficients of about –0.02%/°C. Because the temperature
coefficient is negative, the field strength will be reduced as the temperature rises. Since these
references are temperature cycled during manufacture, their change with temperature is predictable
and retraceable; they will always return to a known value at any specific ambient temperature.
The high-permeability shell which surrounds the reference magnet serves two function: (1) it shields the
magnet from external field, and (2) serves as the flux return path. Physical damage to the outer shell
can cause a permanent change in the gap flux density. Reference magnets should not be dropped or
physically abused. Magnets of this type can have magnetic reference values ranging from 100 G to
20 kG, but the most widely-used value is 1 kG. Reference magnet accuracy is typically ±0.5%, except
for magnets of 200 G or less; for these magnets, the limit of error is generally ±1%. The reference
magnet gap is nominally 0.060 inch but may range from 0.040 to 0.250 inch for special units. The
usable "plateau" in the reference gap generally encompasses an area of about 0.5 square inches.
In reference magnets used for axial field probes, Alnico V or VI is the usual magnet material, charged to
saturation and stabilized down to a particular value. The same temperature coefficients hold true as in
the transverse probe and the same care in handling must be observed. This assembly uses concentric
mu-metal shield cans to protect the magnet from the effects of external magnetic field. Axial reference
magnets are available in values up to 2 kG, with 500 G being the most widely-used value.
When a probe is inserted completely through the access guide, three distinct magnetic peaks will be
observed on the gaussmeter. One peak occurs as the probe enters the magnet, a second (and greater)
peak is observed as the midpoint is reached, and a third (smaller) peak is read as the probe leaves the
magnet. The calibration point is the largest reading in the midpoint area. Its amplitude will be
approximately twice that of the readings that occur where the probe enters or leaves the magnet.
P-450-5-8.bmp
Figure 5-8. Lake Shore Reference Magnets
5-10
Accessories and Probes
Lake Shore Model 450 Gaussmeter User’s Manual
NOTE: Use care to ensure the Zero Gauss Chamber does not become magnetized. Using a
magnetized chamber to zero a probe can lead to erroneous field readings. It is a good
practice to periodically degauss the chamber. If no professional degausser is available,
a bulk tape degausser (Radio Shack P/N 44-232 or equivalent) may be used.
Front View
Side View
32.2 mm
(1.3 in.)
61 mm (2.4 in.)
32.2 mm
(1.3 in)
12.2 mm (0.5 in.) diameter
by 50.8 mm (2 in.) deep bore
C450-5-9.eps
Figure 5-9. Model 4060 Zero Gauss Chamber
Front View
57.2 mm
(2.25 in)
19 mm (0.75 in)
diameter opening
31.8 mm
(1.25 in)
52.4 mm
(2.1 in)
304.8 mm (12 in.)
(Depth of Opening) 279.4 mm (11 in.)
Side View
C450-510.eps
Figure 5-10. Model 4065 Large Zero Gauss Chamber
Accessories and Probes
5-11
Lake Shore Model 450 Gaussmeter User’s Manual
Cable Length: 4.3 meters (14 feet)
C450-511.eps
1
Figure 5-11. Model 4001 RJ-11 Cable Assembly
25
55 mm (2.2 inches)
43 mm
(1.7 inches)
15.8 mm
(0.6 inches)
C450-512.eps
9
32.5 mm
(1.3 inches)
1
Figure 5-12. Model 4002 RJ-11 to DB-25 Adapter
60.3 mm (2.4 inches)
15.9 mm
(0.6 inches)
C450-513.eps
Figure 5-13. Model 4003 RJ-11 to DE-9 Adapter
5-12
Accessories and Probes
Lake Shore Model 450 Gaussmeter User’s Manual
5
6
1
Refer to
“Note”
4
2
NOTE
5
Customer must use 5/64" (2 mm)
hex key to remove four existing
screws from sides of instrument.
3
Unit on right side mounting shown.
Unit on left side also possible.
6
6
4
Item
Description
P/N
Qty
1
Rack Mount Ear
107-440
1
2
Rack Mount Support
107-442
1
3
Rack Mount Panel
107-432
1
4
Rack Mount Handle
107-051-01
2
5
Screw, 6-32 × 3/8 Inch
0-033
4
0-081
6
FHMS Phillips
6
Screw, 8-32 × 3/8 Inch
FHMS Phillips
C-450-5-14.eps
Figure 5-14. Model 4022 Rack-Mount Kit
Accessories and Probes
5-13
Lake Shore Model 450 Gaussmeter User’s Manual
Refer to
“Installation
Procedure”
Installation Procedure
1.
Use 5/64 inch (2 mm) hex key to remove two 6-32 x 1/4
black button head screws from side of Gaussmeter.
2.
Place Gaussmeter on shelf.
3.
Use 5/64 inch (2 mm) hex key to reinstall two 6-32 x 1/4
black button head screws through side of rack into
corresponding holes in the side of the Gaussmeter.
C-450-5-15.eps
Figure 5-15. Model 4026 Dual Rack-Mount Shelf
5-14
Accessories and Probes
Lake Shore Model 450 Gaussmeter User’s Manual
CHAPTER 6
SERVICE
6.0
GENERAL
This chapter covers general maintenance precautions in Paragraph 6.1, electrostatic discharge in
Paragraph 6.2, line voltage selection in Paragraph 6.3, fuse replacement in Paragraph 6.4, rear panel
connector definitions in Paragraph 6.5, optional serial interface cable and adapters in Paragraph 6.6,
operating software EPROM replacement in Paragraph 6.7, and error messages in Paragraph 6.8.
There are no field serviceable parts inside the Model 450. Contact Lake Shore about specific problems
with the Model 450.
6.1
GENERAL MAINTENANCE PRECAUTIONS
The following are general safety precautions unrelated to any other procedure in this publication. Keep
away from live circuits. Installation personnel shall observe all safety regulations at all times. Turn off
system power before making or breaking electrical connections. Regard any exposed connector,
terminal board, or circuit board as a possible shock hazard. Discharge charged components only when
such grounding results in no equipment damage. If a test connection to energized equipment is
required, make the test equipment ground connection before probing the voltage or signal to be tested.
Do not install or service equipment alone. Do not reach into or adjust the equipment without having
another person nearby capable of rendering aid.
If there is no power, verify the power cord is plugged into a live outlet and that both ends are securely
plugged in. Next, check the fuse (refer to Paragraph 6.4).
Use this procedure to periodically clean the instrument to remove dust, grease, and other contaminants:
1. Clean front and back panels and case with soft cloth dampened with a mild detergent and water
solution.
NOTE: Do not use aromatic hydrocarbons or chlorinated solvents to clean the instrument. They may
react with the plastic materials used in the case or the silk screen printing on the back panel.
2. Clean the surface of printed circuit boards (PCBs) with clean, dry air at low pressure.
If the keyboard locks up, hold the Escape key for about 20 seconds to reset the Model 450 to factory
defaults. The gaussmeter then requires the user to re-enter setpoints and zero the probe.
6.2
ELECTROSTATIC DISCHARGE
Electrostatic Discharge (ESD) may damage electronic parts, assemblies, and equipment. ESD is a
transfer of electrostatic charge between bodies at different electrostatic potentials caused by direct
contact or induced by an electrostatic field. The low-energy source that most commonly destroys
Electrostatic Discharge Sensitive (ESDS) devices is the human body, which generates and retains
static electricity. Simply walking across a carpet in low humidity may generate up to 35,000 volts of
static electricity.
Current technology trends toward greater complexity, increased packaging density, and thinner
dielectrics between active elements, which results in electronic devices with even more ESD sensitivity.
Some electronic parts are more ESDS than others. ESD levels of only a few hundred volts may
damage electronic components such as semiconductors, thick and thin film resistors, and piezoelectric
crystals during testing, handling, repair, or assembly. Discharge voltages below 4000 volts cannot be
seen, felt, or heard.
Service
6-1
Lake Shore Model 450 Gaussmeter User’s Manual
6.2.1
Identification of Electrostatic Discharge Sensitive Components
Below are various industry symbols used to label components as ESDS:
6.2.2
Handling Electrostatic Discharge Sensitive Components
Observe all precautions necessary to prevent damage to ESDS components before attempting
installation. Bring the device and everything that contacts it to ground potential by providing a
conductive surface and discharge paths. As a minimum, observe these precautions:
1. De-energize or disconnect all power and signal sources and loads used with unit.
2. Place unit on a grounded conductive work surface.
3. Ground technician through a conductive wrist strap (or other device) using 1 MΩ series resistor to
protect operator.
4. Ground any tools, such as soldering equipment, that will contact unit. Contact with operator's
hands provides a sufficient ground for tools that are otherwise electrically isolated.
5. Place ESDS devices and assemblies removed from a unit on a conductive work surface or in a
conductive container. An operator inserting or removing a device or assembly from a container
must maintain contact with a conductive portion of the container. Use only plastic bags approved
for storage of ESD material.
6. Do not handle ESDS devices unnecessarily or remove from the packages until actually used or
tested.
6.3
LINE VOLTAGE SELECTION
Use the following procedure to change the instrument line voltage selector. Verify the fuse value
whenever line voltage is changed.
WARNING: To avoid potentially lethal shocks, turn off gaussmeter and disconnect it from
AC power before performing these procedures.
1. Identify the line input assembly on the instrument rear panel. See Figure 6-1.
2. Turn the line power switch OFF (O).
3. Remove the instrument power cord.
4. With a small screwdriver, release the drawer holding the line voltage selector and fuse.
5. Slide out the removable plastic fuse holder from the drawer.
6. Rotate the fuse holder until the proper voltage indicator shows through the window.
7. Verify the proper fuse value.
8. Re-assemble the line input assembly in the reverse order.
9. Verify the voltage indicator in the window of the line input assembly.
10. Connect the instrument power cord.
11. Turn the line power switch On (l).
6-2
Service
Lake Shore Model 450 Gaussmeter User’s Manual
Line Cord
Input
Power Switch
O=Off, l=On
Screwdriver
Slot
Fuse
Drawer
LINE
–10% +5% Voltage
50 – 60 Hz
40 VA MAX
120
FUSE DATA
100 / 120 V
0.5 A
0.25 × 1.25 in. T
220 / 240 V
0.25 A
5 × 20 mm T
F-450-6-1.eps
Figure 6-1. Power Fuse Access
6.4
FUSE REPLACEMENT
Below is the procedure to remove and replace a line fuse. There are two basic power configurations:
U.S. and International. Units produced for use in the U.S. have a single fuse on the hot. Units produced
for International use have a double fuse for the hot and neutral. To change line input from the factory
setting, use the appropriate fuse in the connector kit shipped with the instrument. Test fuse with
ohmmeter. Do not rely on visual inspection of fuse.
WARNING: To avoid potentially lethal shocks, turn off gaussmeter and disconnect it from
AC power before performing these procedures.
CAUTION: For continued protection against fire hazard, replace only with the same fuse type and
rating specified for the line for the line voltage selected.
1. Locate line input assembly on the instrument rear panel. See Figure 6-1.
2. Turn power switch Off (O).
3. Remove instrument power cord.
4. With a small screwdriver, release the drawer holding the line voltage selector and fuse.
5. Remove existing fuse(s). Replace with proper Slow-Blow fuse ratings as follows:
100/120 V
0.5 A T 250 V
0.25 × 1.25 inches
220/240 V
0.25 A T 250 V
5 × 20 mm
6. Re-assemble line input assembly in reverse order.
7. Verify voltage indicator in the line input assembly window.
8. Connect instrument power cord.
9. Turn power switch On (l).
Service
6-3
Lake Shore Model 450 Gaussmeter User’s Manual
6.5
REAR PANEL CONNECTOR DEFINITIONS
PROBE INPUT
8
7
15
6
14
5
13
4
12
3
11
2
10
1
9
DA-15 Connector – View looking at rear panel
C450-6-2.eps
Figure 6-2. DA-15 PROBE INPUT Connector Details
PIN
DESCRIPTION
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
Input +
NC
NC
ITEMP +
ITEMP –
NC
NC
Ic +
INPUT –
NC
GND 1
Vcc
A/D CLK
EE-DATA
Ic –
ANALOG OUTPUTS
Corrected
Monitor
..
PIN
DESCRIPTION
1
2
Analog Output – Center Conductor
Ground – Connector Shell
C450-6-3.eps
Figure 6-3. Corrected and Monitor ANALOG OUTPUTS Connector Details
SERIAL I/O
1
2 3
4
5
6
PIN
DESCRIPTION
1
2
3
4
5
6
Serial In (RxD)
Serial In (RxD)
Serial Ground
Serial Ground
Serial Out (TxD)
Serial Out (TxD)
RJ-11
Receptacle
C450-6-4.eps
Figure 6-4. SERIAL I/O RJ-11 Connector Details
6-4
Service
Lake Shore Model 450 Gaussmeter User’s Manual
6.5.1
IEEE-488 INTERFACE CONNECTOR
Connect to the IEEE-488 Interface connector on the Model 450 rear with cables specified in the
IEEE-488-1978 standard document. The cable has 24 conductors with an outer shield. The
connectors are 24-way Amphenol 57 Series (or equivalent) with piggyback receptacles to allow daisychaining in multiple device systems. The connectors are secured in the receptacles by two captive
locking screws with metric threads.
The total length of cable allowed in a system is 2 meters for each device on the bus, or 20 meters
maximum. A system may be composed of up to 15 devices. Figure 6-5 shows the IEEE-488 Interface
connector pin location and signal names as viewed from the Model 450 rear panel.
IEEE-488 INTERFACE
SH1 AH1 T5 L4 SR1 RL1 PP0 DC1 DT0 C0 E1
12
11
10
9
8
7
6
5
4
3
2
1
24
23
22
21
20
19
18
17
16
15
14
13
C450-6-5.eps
PIN
SYMBOL
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
DIO1
DIO2
DIO3
DIO4
EOI
DAV
NRFD
NDAC
IFC
SRQ
ATN
SHIELD
DIO5
DIO6
DIO7
DIO8
REN
GND 6
GND 7
GND 8
GND 9
GND 10
GND11
GND
DESCRIPTION
Data Input/Output Line 1
Data Input/Output Line 2
Data Input/Output Line 3
Data Input/Output Line 4
End Or Identify
Data Valid
Not Ready For Data
Not Data Accepted
Interface Clear
Service Request
Attention
Cable Shield
Data Input/Output Line 5
Data Input/Output Line 6
Data Input/Output Line 7
Data Input/Output Line 8
Remote Enable
Ground Wire – Twisted pair with DAV
Ground Wire – Twisted pair with NRFD
Ground Wire – Twisted pair with NDAC
Ground Wire – Twisted pair with IFC
Ground Wire – Twisted pair with SRQ
Ground Wire – Twisted pair with ATN
Logic Ground
Figure 6-5. IEEE-488 Rear Panel Connector Details
Service
6-5
Lake Shore Model 450 Gaussmeter User’s Manual
6.6
OPTIONAL SERIAL INTERFACE CABLE AND ADAPTERS
1 2
TxD
Gnd
Gnd
RxD
1 2 3 4 5 6
3 4 5 6
To aid in Serial Interface troubleshooting, Figures 6-6 thru 6-8 show wiring information for the optional
cable assembly and the two mating adapters.
YELLOW
GREEN
RED
BLACK
Figure 6-6. Model 2001 RJ-11 Cable Assembly Wiring Details
13
12
25
11
24
10
23
9
22
8
21
7
6
20
5
19
4
18
DB25
CONNECTOR
17
3
16
2
15
1
14
RxD
= NOT USED
Gnd
TxD
For Customer-supplied
computer with DB-25
Serial Interface
Connector configured as
DCE. If the interface is
DTE, a Null Modem
Adapter is required to
exchange Transmit and
Receive lines.
1
2
3
4
5
6
RJ11
RECEPTACLE
Figure 6-7. Model 2002 RJ-11 to DB-25 Adapter Wiring Details
5
4
9
3
8
2
7
1
6
DB9 CONNECTOR
= NOT USED
RxD
TxD
Gnd
For Customer-supplied
computer with DE-9
Serial Interface
Connector configured as
DTE. If the interface is
DCE, a Null Modem
Adapter is required to
exchange Transmit and
Receive lines.
1
2 3
4
5
6
RJ11
RECEPTACLE
Figure 6-8. Model 2003 RJ-11 to DE-9 Adapter Wiring Details
6-6
Service
Lake Shore Model 450 Gaussmeter User’s Manual
6.7
OPERATING SOFTWARE EPROM REPLACEMENT
The operating software for the Model 450 is contained on one Erasable Programmable Read Only
Memory (EPROM) Integrated Circuit (IC). The EPROM is numbered U36 and located just behind the
microprocessor IC (U31). The EPROM also has a label on top identifying the software version and date
(see Figure 6-9). Use the procedure below to replace the operating software EPROM.
WARNING:
To avoid potentially lethal shocks, turn off the instrument and disconnect
it from the AC power line before performing this procedure.
1. Set power switch to Off (O) and disconnect power cord from rear of unit.
2. Use 5/64 hex key to remove four screws attaching top panel to unit.
3. Use 5/64 hex key to loosen two screws attaching bottom panel to unit.
4. Carefully remove back bezel.
5. Slide top panel back and remove from unit.
6. Locate software EPROM U36 on main circuit board. Note its orientation (circular notch on front
of IC). See Figure 6-9.
7. Use IC puller to remove existing EPROM from socket.
8. Use IC insertion tool to place new EPROM into socket, noting its orientation.
9. Replace top of enclosure and secure with four screws.
10. Replace back bezel and use 5/64 hex key to tighten two screws attaching bottom panel to unit.
11. Reconnect power cord to rear of unit and set power switch to On (l).
12. Perform the initial setup and system checkout (Paragraph 2.4). When replacing the operating
software EPROM, all operating parameters reset to factory defaults specified in Paragraph 3.14.
Rear
Front
Operating Software
EPROM
U36
Fuse
Transformer
Power Inlet
C-450-U-6-9
Figure 6-9. Location Of Operating Software EPROM
Service
6-7
Lake Shore Model 450 Gaussmeter User’s Manual
This Page Intentionally Left Blank
6-8
Service
Lake Shore Model 450 Gaussmeter User’s Manual
APPENDIX A
GLOSSARY OF TERMINOLOGY
2
accuracy. The degree of correctness with which a measured value agrees with the true value.
electronic accuracy. The accuracy of an instrument independent of the sensor.
sensor accuracy. The accuracy of a Hall generator and its associated calibration.
1
algorithm. A set of well-defined rules for the solution of a problem in a finite number of steps.
American Standard Code for Information Exchange (ASCII). A standard code used in data transmission, in which
128 numerals, letters, symbols, and special control codes are represented by a 7-bit binary number as follows:
American Wire Gage (AWG). Wiring sizes are defined as diameters in inches and millimeters as follows:
AWG
1
2
3
4
5
6
7
8
9
10
Dia. In.
0.2893
0.2576
0.2294
0.2043
0.1819
0.1620
0.1443
0.1285
0.1144
0.1019
Dia. mm
7.348
6.544
5.827
5.189
4.621
4.115
3.665
3.264
2.906
2.588
AWG
11
12
13
14
15
16
17
18
19
20
Dia. In.
0.0907
0.0808
0.0720
0.0641
0.0571
0.0508
0.0453
0.0403
0.0359
0.0338
Dia. mm
2.304
2.053
1.829
1.628
1.450
1.291
1.150
1.024
0.9116
0.8118
AWG
21
22
23
24
25
26
27
28
29
30
Dia. In.
0.0285
0.0253
0.0226
0.0207
0.0179
0.0159
0.0142
0.0126
0.0113
0.0100
Dia. mm
0.7230
0.6438
0.5733
0.5106
0.4547
0.4049
0.3606
0.3211
0.2859
0.2546
AWG
31
32
33
34
35
36
37
38
39
40
Dia. In.
0.0089
0.0080
0.00708
0.00630
0.00561
0.00500
0.00445
0.00397
0.00353
0.00314
Dia. mm
0.2268
0.2019
0.178
0.152
0.138
0.127
0.1131
0.1007
0.08969
0.07987
ampere. The constant current that, if maintained in two straight parallel conductors of infinite length, of negligible circular
cross section, and placed one meter apart in a vacuum, would produce between these conductors a force equal to
-7
2
2 x 10 newton per meter of length. This is one of the base units of the SI.
ampere-turn. A MKS unit of magnetomotive force equal to the magnetomotive force around a path linking one turn of a
conducting loop carrying a current of one ampere; or 1.26 gilberts.
ampere/meter (A/m). The SI unit for magnetic field strength (H). 1 ampere/meter = 4π/1000 oersted ≈0.01257 oersted.
1
analog data. Data represented in a continuous form, as contrasted with digital data having discrete values.
analog output. A voltage output from an instrument that is proportional to its input. From an instrument such as a digital
voltmeter, the output voltage is generated by a digital-to-analog converter with a discrete number of voltage levels.
2
anode. The terminal that is positive with respect to the other terminal when the diode is biased in the forward direction.
Cathode –
+ Anode
1
area. A measure of the size of a two-dimensional surface, or of a region on such a surface.
area·turns. A coil parameter produced by the multiplication of a magnet's area and number of turns. Gives an indication
of the sensitivity of a coil. In the Model 480, the area turns of a coil must be entered to perform flux density
measurements in units of gauss (G) or tesla (T).
B. Symbol for magnetic flux density. See Magnetic Flux Density.
baud. A unit of signaling speed equal to the number of discrete conditions or signal events per second, or the reciprocal
2
of the time of the shortest signal element in a character.
2
bit. A contraction of the term “binary digit”; a unit of information represented by either a zero or a one.
Glossary of Terminology
A-1
Lake Shore Model 450 Gaussmeter User’s Manual
calibration. To determine, by measurement or comparison with a standard, the correct (accurate) value of each scale
1
reading on a meter or other device, or the correct value for each setting of a control knob.
2
cathode. The terminal from which forward current flows to the external circuit.
Cathode –
+ Anode
Celsius (°C) Scale. A temperature scale that registers the freezing point of water as 0 °C and the boiling point as 100 °C
under normal atmospheric pressure. Celsius degrees are purely derived units, calculated from the Kelvin
Thermodynamic Scale. Formerly known as “centigrade.” See Temperature for conversions.
2
cgs system of units. A system in which the basic units are the centimeter, gram, and second.
coercive force (coercive field). The magnetic field strength (H) required to reduce the magnetic induction (B) in a
magnetic material to zero.
coercivity. generally used to designate the magnetic field strength (H) required to reduce the magnetic induction (B) in a
magnetic material to zero from saturation. The coercivity would be the upper limit to the coercive force.
compliance voltage. See current source.
Curie temperature (Tc). Temperature at which a magnetized sample is completely demagnetized due to thermal
agitation. Named for Pierre Curie (1859-1906), a French chemist.
current source. A type of power supply that supplies a constant current through a variable load resistance by
automatically varying its compliance voltage. A single specification given as “compliance voltage” means the output
current is within specification when the compliance voltage is between zero and the specified voltage.
demagnetization. when a sample is exposed to an applied field (Ha), poles are induced on the surface of the sample.
Some of the returned flux from these poles is inside of the sample. This returned flux tends to decrease the net
magnetic field strength internal to the sample yielding a true internal field (Hint) given by: Hint = Ha – DM ,where M is the
volume magnetization and D is the demagnetization factor. D is dependent on the sample geometry and orientation with
respect to the field.
deviation. The difference between the actual value of a controlled variable and the desired value corresponding to the
1
setpoint.
differential permeability. The slope of a B versus H curve: µd = dB/dH.
differential susceptibility. The slope of a M versus H curve: χd = dM/dH.
digital controller. A feedback control system where the feedback device (sensor) and control actuator (heater) are joined
by a digital processor. In Lake Shore controllers the heater output is maintained as a variable DC current source.
2
digital data. Pertaining to data in the form of digits or interval quantities. Contrast with analog data.
dimensionless sensitivity. Sensitivity of a physical quantity to a stimulus, expressed in dimensionless terms. The
dimensionless temperature sensitivity of a resistance temperature sensor is expressed as Sd = (T/R)(dR/dT) which is
also equal to the slope of R versus T on a log-log plot, that is Sd = d lnR / d lnT. Note that the absolute temperature (in
kelvin) must be used in these expressions.
drift, instrument. An undesired but relatively slow change in output over a period of time, with a fixed reference input.
2
Note: Drift is usually expressed in percent of the maximum rated value of the variable being measured.
dynamic data exchange (DDE). A method of interprocess communication which passes data between processes and
synchronized events. DDE uses shared memory to exchange data between applications and a protocol to synchronize
the passing of data.
dynamic link library (DLL). A module that contains code, data, and Windows resources that multiple Windows programs
can access.
electromagnet. A device in which a magnetic field is generated as the result of electrical current passing through a helical
conducting coil. It can be configured as an iron-free solenoid in which the field is produced along the axis of the coil, or
an iron-cored structure in which the field is produced in an air gap between pole faces. The coil can be water cooled
copper or aluminum, or superconductive.
electron. An elementary particle containing the smallest negative electric charge. Note: The mass of the electron is
2
approximately equal to 1/1837 of the mass of the hydrogen atom.
electrostatic discharge (ESD). A transfer of electrostatic charge between bodies at different electrostatic potentials
caused by direct contact or induced by an electrostatic field.
error. Any discrepancy between a computed, observed, or measured quantity and the true, specified, or theoretically
2
correct value or condition.
Fahrenheit (°F) Scale. A temperature scale that registers the freezing point of water as 32 °F and the boiling point as
212 °F under normal atmospheric pressure. See Temperature for conversions.
1
flux (φ). The electric or magnetic lines of force in a region.
flux density (B). Any vector field whose flux is a significant physical quantity; examples are magnetic flux density, electric
1
displacement, and gravitational field.
gamma. A cgs unit of low-level flux density, where 100,000 gamma equals one oersted, or 1 gamma equals
-5
10 oersted.
A-2
Glossary of Terminology
Lake Shore Model 450 Gaussmeter User’s Manual
-4
2
2
gauss (G). The cgs unit for magnetic flux density (B). 1 gauss = 10 tesla = 1 Mx/cm = line/cm . Named for Karl Fredrich
Gauss (1777-1855) a German mathematician, astronomer, and physicist.
gaussian system (units). A system in which centimeter-gram-second units are used for electric and magnetic qualities.
general purpose interface bus (GPIB). Another term for the IEEE-488 bus.
gilbert (Gb). A cgs electromagnetic unit of the magnetomotive force required to produce one maxwell of magnetic flux in
a magnetic circuit of unit reluctance. One gilbert is equal to 10/4π ampere-turn. Named for William Gilbert (1540-1603),
an English physicist; hypothesized that the earth is a magnet.
gilbert per centimeter. Practical cgs unit of magnet intensity. Gilberts per cm are the same as oersteds.
Greek alphabet. The Greek alphabet is defined as follows:
Alpha
Beta
Gamma
Delta
Epsilon
Zeta
Eta
Theta
α
β
γ
δ
ε
ζ
η
θ
Α
Β
Γ
∆
Ε
Ζ
Η
Θ
Iota
Kappa
Lambda
Mu
Nu
Xi
Omicron
Pi
ι
κ
λ
µ
ν
ξ
ο
π
Ι
Κ
Λ
Μ
Ν
Ξ
Ο
Π
Rho
Sigma
Tau
Upsilon
Phi
Chi
Psi
Omega
ρ
σ
τ
υ
φ
χ
ψ
ω
Ρ
Σ
Τ
Υ
Φ
Χ
Ψ
Ω
ground. A conducting connection, whether intentional or accidental, by which an electric circuit or equipment is connected
to the earth, or to some conducting body of large extent that serves in place of the earth. Note: It is used for establishing
and maintaining the potential of the earth (or of the conducting body) or approximately that potential, on conductors
2
connected to it, and for conducting ground current to and from the earth (or of the conducting body).
H. Symbol for magnetic field strength. See Magnetic Field Strength.
Hall effect. The generation of an electric potential perpendicular to both an electric current flowing along a thin conducting
material and an external magnetic field applied at right angles to the current. Named for Edwin H. Hall (1855-1938), an
American physicist.
2
Hall mobility. The quantity µH in the relation µH = Rσ, where R = Hall coefficient and σ = conductivity.
Helmholtz coils. A pair of flat, circular coils having equal numbers of turns and equal diameters, arranged with a common
1
axis, and connected in series; used to obtain a magnetic field more nearly uniform than that of a single coil.
hertz (Hz). A unit of frequency equal to one cycle per second.
hole. A mobile vacancy in the electronic valence structure of a semiconductor that acts like a positive electron charge with
2
a positive mass.
hysteresis. The dependence of the state of a system on its previous history, generally in the form of a lagging of a
1
physical effect behind its cause. Also see magnetic hysteresis.
IEEE. Institute of Electrical and Electronics Engineers.
IEEE-488. An instrumentation bus with hardware and programming standards designed to simplify instrument interfacing.
The addressable, parallel bus specification is defined by the IEEE.
initial permeability. The permeability determined at H = 0 and B = 0.
initial susceptibility. The susceptibility determined at H = 0 and M = 0.
1
integrator. A circuit or network whose output waveform is the time integral of its input waveform. In the Model 480, the
input is a voltage with the integral output being in volt seconds (V·s).
international system of units (SI). A universal coherent system of units in which the following seven units are
considered basic: meter, kilogram, second, ampere, kelvin, mole, and candela. The International System of Units, or
Système International d'Unités (SI), was promulgated in 1960 by the Eleventh General Conference on Weights and
Measures. For definition, spelling, and protocols, see Reference 3 for a short, convenient guide.
interpolation table. A table listing the output and sensitivity of a sensor at regular or defined points which may be
different from the points at which calibration data was taken.
intrinsic coercivity. The magnetic field strength (H) required to reduce the magnetization (M) or intrinsic induction in a
magnetic material to zero.
intrinsic induction. The contribution of the magnetic material (Bi) to the total magnetic induction (B).
Bi = B – µoH (SI)
Bi = B – H (cgs)
isolated (neutral system). A system that has no intentional connection to ground except through indicating, measuring, or
2
protective devices of very-high impedance.
Kelvin (K). The unit of temperature on the Kelvin Scale. It is one of the base units of SI. The word “degree” and its symbol
(°) are omitted from this unit. See Temperature Scale for conversions.
Kelvin Scale. The Kelvin Thermodynamic Temperature Scale is the basis for all international scales, including ITS-90. It
is fixed at two points: the absolute zero of temperature (0 K), and the triple point of water (273.16 K), the equilibrium
temperature that pure water reaches in the presence of ice and its own vapor.
Glossary of Terminology
A-3
Lake Shore Model 450 Gaussmeter User’s Manual
line regulation. The maximum steady-state amount that the output voltage or current will change as the result of a
specified change in input line voltage (usually for a step change between 105-125 or 210-250 volts, unless otherwise
specified).
line of flux. An imaginary line in a magnetic field of force whose tangent at any point gives the direction of the field at that
point; the lines are spaced so that the number through a unit area perpendicular to the field represents the intensity of
the field. Also know as a Maxwell in the cgs system of units.
line voltage. The RMS voltage of the primary power source to an instrument.
load regulation. A steady-state decrease of the value of the specified variable resulting from a specified increase in load,
generally from no-load to full-load unless otherwise specified.
M. Symbol for magnetization. See magnetization.
magnetic air gap. The air space, or non-magnetic portion, of a magnetic circuit.
magnetic field strength (H). The magnetizing force generated by currents and magnetic poles. For most applications,
the magnetic field strength can be thought of as the applied field generated, for example, by a superconducting magnet.
The magnetic field strength is not a property of materials. Measure in SI units of A/m or cgs units of oersted.
magnetic flux density (B). Also referred to as magnetic induction. This is the net magnetic response of a medium to an
applied field, H. The relationship is given by the following equation: B = µo(H + M) for SI, and B = H + 4πM for cgs,
-7
where H = magnetic field strength, M = magnetization, and µo = permeability of free space = 4π x 10 H/m.
magnetic hysteresis. The property of a magnetic material where the magnetic induction (B) for a given magnetic field
strength (H) depends upon the past history of the samples magnetization.
magnetic induction (B). See magnetic flux density.
magnetic moment (m). This is the fundamental magnetic property measured with dc magnetic measurements systems
such as a vibrating sample magnetometer, extraction magnetometer, SQUID magnetometer, etc. The exact technical
definition relates to the torque exerted on a magnetized sample when placed in a magnetic field. Note that the moment
is a total attribute of a sample and alone does not necessarily supply sufficient information in understanding material
properties. A small highly magnetic sample can have exactly the same moment as a larger weakly magnetic sample
2
-3
2
(see Magnetization). Measured in SI units as A·m and in cgs units as emu. 1 emu = 10 A·m .
magnetic scalar potential. The work which must be done against a magnetic field to bring a magnetic pole of unit
1
strength from a reference point (usually at infinity) to the point in question. Also know as magnetic potential.
magnetic units. Units used in measuring magnetic quantities. Includes ampere-turn, gauss, gilbert, line of force, maxwell,
oersted, and unit magnetic pole.
magnetization (M). This is a material specific property defined as the magnetic moment (m) per unit volume (V). M =
3
3
3
m/V. Measured in SI units as A/m and in cgs units as emu/cm . 1 emu/cm = 10 A/m. Since the mass of a sample is
generally much easier to determine than the volume, magnetization is often alternately expressed as a mass
magnetization defined as the moment per unit mass.
1
magnetostatic. Pertaining to magnetic properties that do not depend upon the motion of magnetic fields.
Maxwell (Mx). A cgs electromagnetic unit of magnetic flux, equal to the magnetic flux which produces an electromotive
1
force of 1 abvolt in a circuit of one turn link the flux, as the flux is reduced to zero in 1 second at a uniform rate.
MKSA System of Units. A system in which the basic units are the meter, kilogram, and second, and the ampere is a
-7
derived unit defined by assigning the magnitude 4π x 10 to the rationalized magnetic constant (sometimes called the
permeability of space).
NBS. National Bureau of Standards. Now referred to as NIST.
National Institute of Standards and Technology (NIST). Government agency located in Gaithersburg, Maryland and
Boulder, Colorado, that defines measurement standards in the United States. See Standards Laboratories for an
international listing.
noise (electrical). Unwanted electrical signals that produce undesirable effects in circuits of control systems in which they
2
occur.
normalized sensitivity. For resistors, signal sensitivity (dR/dT) is geometry dependent; i.e., dR/dT scales directly with R;
consequently, very often this sensitivity is normalized by dividing by the measured resistance to give a sensitivity, sT, in
percent change per kelvin. sT = (100/R) (dR/dT) %K, where T is temperature in kelvin and R is resistance in ohms.
normally closed (N.C.). A term used for switches and relay contacts. Provides a closed circuit when actuator is in the
free (unenergized) position.
normally open (N.O.). A term used for switches and relay contacts. Provides an open circuit when actuator is in the free
(unenergized) position.
3
oersted (Oe). The cgs unit for the magnetic field strength (H). 1 oersted = 10 /4π ampere/meter ≈ 79.58 ampere/meter.
ohm (Ω). The SI unit of resistance (and of impedance). The ohm is the resistance of a conductor such that a constant
2
current of one ampere in it produces a voltage of one volt between its ends.
2
-4
-5
2
-3
pascal (Pa). The SI unit of pressure equal to 1 N/m . Equal to 1.45x10 psi, 1.0197x10 kgf /cm , 7.5x10 torr,
-3
-5
4.191x10 inches of water, or 1x10 bar.
A-4
Glossary of Terminology
Lake Shore Model 450 Gaussmeter User’s Manual
permeability. Material parameter which is the ratio of the magnetic induction (B) to the magnetic field strength (H):
µ = B/H. Also see Initial Permeability and Differential Permeability.
polynomial fit. A mathematical equation used to fit calibration data. Polynomials are constructed of finite sums of terms
th
of the form aixi , where ai is the i fit coefficient and xi is some function of the dependent variable.
pounds per square inch (psi). A unit of pressure. 1 psi = 6.89473 kPa. Variations include psi absolute (psia) measured
relative to vacuum (zero pressure) where one atmosphere pressure equals 14.696 psia and psi gauge (psig) where
gauge measured relative to atmospheric or some other reference pressure.
-6
ppm. Parts per million, e.g., 4 x 10 is four parts per million.
precision. Careful measurement under controlled conditions which can be repeated with similar results. See repeatability.
Also means that small differences can be detected and measured with confidence. See resolution.
prefixes. SI prefixes used throughout this manual are as follows:
Factor
1024
1021
1018
1015
1012
109
106
103
102
101
Prefix
yotta
zetta
exa
peta
tera
giga
mega
kilo
hecto
deka
Symbol
Factor
Prefix
Symbol
Y
Z
E
P
T
G
M
k
h
da
10–1
10–2
10–3
10–6
10–9
10–12
10–15
10–18
10–21
10–24
deci
centi
milli
micro
nano
pico
femto
atto
zepto
yocto
d
c
m
µ
n
p
f
a
z
y
probe. A long, thin body containing a sensing element which can be inserted into a system in order to make
measurements. Typically, the measurement is localized to the region near the tip of the probe.
remanence. The remaining magnetic induction in a magnetic material when the material is first saturated and then the
applied field is reduced to zero. The remanence would be the upper limit to values for the remanent induction. Note that
no strict convention exists for the use of remanent induction and remanence and in some contexts the two terms may
be used interchangeably.
remanent induction. The remaining magnetic induction in a magnetic material after an applied field is reduced to zero.
Also see remanence.
repeatability. The closeness of agreement among repeated measurements of the same variable under the same
2
conditions.
2
resolution. The degree to which nearly equal values of a quantity can be discriminated.
display resolution. The resolution the physical display of an instrument. This is not always the same as the
n
measurement resolution of the instrument. Decimal display resolution specified as "n digits" has 10 possible display
n
values. A resolution of n and one-half digits has 2 x 10 possible values.
measurement resolution. The ability of an instrument to resolve a measured quantity. For digital instrumentation this
n
is often defined by the analog to digital converter being used. A n-bit converter can resolve one part in 2 . The
n
smallest signal change that can be measured is the full scale input divided by 2 for any given range. Resolution
should not be confused with accuracy.
root mean square (RMS). The square root of the time average of the square of a quantity; for a periodic quantity the
1
average is taken over one complete cycle. Also known as effective value.
RS-232C. Bi-directional computer serial interface standard defined by the Electronic Industries Association (EIA). The
interface is single-ended and non-addressable.
1
scalar. A quantity which has magnitude only and no direction, in contrast to a vector.
semiconducting material. A conducting medium in which the conduction is by electrons, and holes, and whose
2
temperature coefficient of resistivity is negative over some temperature range below the melting point.
semiconductor. An electronic conductor, with resistivity in the range between metals and insulators, in which the electric
charge carrier concentration increases with increasing temperature over some temperature range. Note: Certain
2
semiconductors possess two types of carriers, namely, negative electrons and positive holes.
sensitivity. The ratio of the response or change induced in the output to a stimulus or change in the input. Temperature
sensitivity of a resistance temperature detector is expressed as S = dR/dT.
1
setpoint. The value selected to be maintained by an automatic controller.
serial interface. A computer interface where information is transferred one bit at a time rather than one byte (character)
at a time as in a parallel interface. RS-232C is a common serial interface.
SI. Système International d'Unités. See International System of Units.
stability. The ability of an instrument or sensor to maintain a constant output given a constant input.
Glossary of Terminology
A-5
Lake Shore Model 450 Gaussmeter User’s Manual
susceptance. In electrical terms, susceptance is defined as the reciprocal of reactance and the imaginary part of the
complex representation of admittance: [suscept(ibility) + (conduct)ance].
susceptibility (χ). Parameter giving an indication of the response of a material to an applied magnetic field. The
susceptibility is the ratio of the magnetization (M) to the applied field (H). χ = M/H. In both SI units and cgs units the
volume susceptibility is a dimensionless parameter. Multiply the cgs susceptibility by 4π to yield the SI susceptibility.
See also Initial Susceptibility and Differential Susceptibility. As in the case of magnetization, the susceptibility is often
seen expressed as a mass susceptibility or a molar susceptibility depending upon how M is expressed.
temperature scales. See Kelvin Scale, Celsius Scale, and ITS-90. Proper metric usage requires that only kelvin and
degrees Celsius be used. However, since degrees Fahrenheit is in such common use, all three scales are delineated as
follows:
Boiling point of water
Triple point of water
Freezing point of water
373.15 K
273.16 K
273.15 K
Absolute zero
0K
kelvin
100 °C
212 °F
0 °C
32 °F
–273.15 °C
Celsius
–459.67 °F
Fahrenheit
To convert kelvin to Celsius, subtract 273.15.
To convert Celsius to Fahrenheit: multiply °C by 1.8 then add 32, or: °F = (1.8 x °C) + 32.
To convert Fahrenheit to Celsius: subtract 32 from °F then divide by 1.8, or: °C = (°F. 32 )/ 1.8.
temperature coefficient, measurement. The measurement accuracy of an instrument is affected by changes in ambient
temperature. The error is specified as an amount of change (usually in percent) for every one degree change in ambient
temperature.
4
tesla (T). The SI unit for magnetic flux density (B). 1 tesla = 10 gauss
thermal emf. An electromotive force arising from a difference in temperature at two points along a circuit, as in the
1
Seebeck effect.
tolerance. The range between allowable maximum and minimum values.
turns (N). One complete loop of wire. In the Model 480, the turns of a coil must be entered to perform flux measurements
in units of Volt seconds (V·sφ), Webers (Wbφ), or Maxwells (Mxφ).
Underwriters Laboratories (UL). An independent laboratory that establishes standards for commercial and industrial
products.
unit magnetic pole. A pole with a strength such that when it is placed 1 cm away from a like pole, the force between the
two is 1 dyne.
vector. A quantity that has both magnitude and direction, and whose components transform from one coordinate system
1
to another in the same manner as the components of a displacement. Also known as a polar vector.
volt (V). The difference of electric potential between two points of a conductor carrying a constant current of one ampere,
2
when the power dissipated between these points is equal to one watt.
volt-ampere (VA). The SI unit of apparent power. The volt-ampere is the apparent power at the points of entry of a singlephase, two-wire system when the product of the RMS value in amperes of the current by the RMS value in volts of the
2
voltage is equal to one.
2
watt (W). The SI unit of power. The watt is the power required to do work at the rate of 1 joule per second.
weber (Wb). The unit of magnetic flux in the mks system, equal to the magnetic flux which, linking a circuit of one turn,
1
produces in it an electromotive force of 1 volt as it is reduced to zero at a uniform rate in 1 second.
References:
1
Sybil P. Parker, Editor. Dictionary of Scientific and Technical Terms: Third Edition. New York: McGraw Hill, 1969
(IBSN 0-395-20360-0)
2
Christopher J. Booth, Editor. The New IEEE Standard Dictionary of Electrical and Electronic Terms: IEEE Std 100-1992, Fifth
Edition. New York: Institute of Electrical and Electronics Engineers, 1993 (IBSN 1-55937-240-0). Definitions printed with permission
of the IEEE.
3
Nelson, Robert A. Guide For Metric Practice, Page BG7 - 8, Physics Today, Eleventh Annual Buyer’s Guide, August 1994
(ISSN 0031-9228 coden PHTOAD)
A-6
Glossary of Terminology
Lake Shore Model 450 Gaussmeter User’s Manual
APPENDIX B
UNITS FOR MAGNETIC PROPERTIES
Conversion from CGS to SI Units
Quantity
Symbol
Gaussian
a
& CGS emu
Conversion
b
Factor, C
Magnetic flux density,
Magnetic induction
B
gauss (G)
Magnetic Flux
φ
maxwell (Mx), G•cm
Magnetic potential difference,
magnetomotive force
U, F
gilbert (Gb)
Magnetic field strength,
magnetizing force
H
oersted (Oe), Gb/cm
(Volume) magnetizationg
(Volume) magnetization
Magnetic polarization,
intensity of
magnetization
M
4πM
emu/cm
G
J, I
emu/cm
(Mass) magnetization
σ, M
emu/g
Magnetic moment
m
emu, erg/G
Magnetic dipole moment
j
(Volume) susceptibility
χ, κ
emu, erg/G
dimensionless
3
emu/cm
(Mass) susceptibility
χρ, κρ
cm /g, emu/g
(Molar) susceptibility
χmol, κmol
cm /mol, emu/mol
Permeability
Relative permeabilityj
(Volume) energy density,
energy productk
µ
µr
dimensionless
not defined
W
erg/cm
Demagnetization factor
D, N
dimensionless
d
10
2
e
2
tesla (T), Wb/m
-4
10-8
weber (Wb), volt
second (V•s)
10/4π
ampere (A)
3
A/m
10 /4π
3h
10
3
10 /4π
3
4π x 10
3
3
3
SI &
c
Rationalized mks
3
-4
1
-7
4π x 10
10
-3
-10
4π x 10
2
-7
(4π) x 10
A/m
A/m
T, Wb/m
2i
2
A•m /kg
Wb•m/kg
2
A•m , joule per
tesla (J/T)
i
Wb•m
Henry per meter
(H/m), Wb/(A•m)
-3
m /kg
2
H•m /kg
-6
m /mol
2
H•m /mol
H/m, Wb/(A•m)
dimensionless
4π x 10 -10
(4π)2 x 10
4π2x 10 -13
(4π) x 10
-7
4π x 10
10
f
-1
1/4π
3
3
J/m
3
dimensionless
NOTES:
a.
Gaussian units and cgs emu are the same for magnetic properties. The defining relation is B = H + 4πM.
b.
Multiply a number in Gaussian units by C to convert it to SI (e.g. 1 G x 10-4T/G = 10-4T).
c.
SI (Système International d'Unités) has been adopted by the National Bureau of Standards. Where two conversion factors are given, the
upper one is recognized under, or consistent with, SI and is based on the definition B = µ0(H + M), where to µ0 = 4π x 10-7H/m. The lower one
is not recognized under SI and is based on the definition B = µ0H + J, where the symbol I is often used in place of J.
d.
1 gauss = 105 gamma (γ).
e.
Both oersted and gauss are expressed as cm-½ •g½•s-1 in terms of base units.
f.
A/m was often expressed as "ampere-turn per meter" when used for magnetic field strength.
g.
Magnetic moment per unit volume.
h.
The designation "emu" is not a unit.
i.
Recognized under SI, even though based on the definition B = µ0H + J. See footnote c.
j.
µr = µ/µ0 = 1 + χ, all in SI. µr is equal to Gaussian µ.
k.
B • H and µ0M • H have SI units J/m3, M • H and B • H/4π have Gaussian units erg/cm3.
R.B. Goldfarb and F.R. Fickett, U.S. Department of Commerce, National Bureau of Standards, Bolder, Colorado 80303, March 1985, NBS Special
Publication 696. For sale by the Superintendent of Documents, U.S. Government Printing Office, Washington, D.C. 20402.
Units for Magnetic Properties
B-1
Lake Shore Model 450 Gaussmeter User’s Manual
Table B-2. Recommended SI Values for Physical Constants
Quantity
Symbol
Value (SI units)
Permeability of Vacuum
µ0
4π x 10 H m
Speed of Light in Vacuum
c
2.9979 x 10 m s
Permitivity of Vacuum
ε0 = (µ0c )
Fine Structure Constant, µ0ce2/2h
α
-1
α
Elementary Charge
e
-7
-1
8
2 -1
8.8542 x 10
-1
-12
Fm
-1
0.0073
137.0360
1.6022 x 10
C
-34
-1
6.6262 x 10 J Hz
-34
1.0546 x 10 J s
Plank's Constant
h
h = h/2π
Avogadro's Constant
NA
Atomic Mass Unit
lu = (10 kg mol /NA
6.0220 x 10
-3
-19
-1
23
1.6605 x 10
mol
-27
-1
kg
-30
Electron Rest Mass
me
Proton Rest Mass
mp
Neutron Rest Mass
mn
Magnetic Flux Quantum
φ = h/2e
h/e
Josephson Frequency-Voltage Ratio
2e/h
0.9109 x 10 kg
-4
5.4858 x 10 u
-27
1.6726 x 10 kg
1.0073 u
-27
1.6749 x 10 kg
1.0087 u
-15
2.0679 x 10 Wb
-15
-1
-1
4.1357 x 10 J Hz C
483.5939 THz V
-4
-1
-1
-1
Quantum of Circulation
h/2me
h/me
3.6369 x 10 J Hz kg
-4
-1 -1
7.2739 x 10 J Hz C
Rydberg Constant
R∞
1.0974 x 10 m-1
Proton Moment in Nuclear Magnetons
µp/µN
2.7928
Bohr Magneton
µB = eh/2me
Proton Gyromagnetic Ratio
γp
2.6752 x 10 s T
Diamagnetic Shielding Factor, Spherical H2O Sample
1 + σ(H2O)
1.0000
Molar Mass Constant
R
8.3144 J mol K
Molar Volume, Ideal Gas (T0 = 273.15K, p0 = 1 atm)
Vm = RT0/p0
0,0224 m mol
Boltzman Constant
k = R/NA
Stefan-Boltzman Constant
σ = (π /60) k /h c
First Radiation Constant
c1= 2πhc
Second Radiation Constant
c2 = hc/k
Gravitation Constant
G
2
7
9.2741 x 10
-24
JT
-1
8
-1
-1
4
1.3807 x 10
3
2
3
2
-23
-1
-1
-1
-1
JK
-8
-2
-4
5.6703 x 10 W m K
3.7418 x 10
-16
-2
Wm
0.0144 mK
6.6720 x 10
-11
2
N m kg
-2
Data (abbreviated to 4 decimal places) from CODATA Bulletin No. 11, ICSU CODATA Central Office,
19 Westendstrasse, 6 Frankfurt/Main, Germany. Copies of this bulletin are available from this office.
B-2
Units for Magnetic Properties
Lake Shore Model 450 Gaussmeter User’s Manual
APPENDIX C
HALL GENERATORS
C1.0
GENERAL
This chapter provides theory of operation, specifications, mechanical drawings, and definition of
terminology. Hall Generator theory of operation is detailed in Paragraph C2.0. Generic Hall generator
hookup is detailed in Paragraph C3.0. Hookup to a Model 450 Gaussmeter is discussed in
Paragraph C4.0. Specifications of the various available Hall generators are detailed in
Paragraph C5.0. Finally, the HALLCAL.EXE program is detailed in Paragraph C6.0. Additional
installation and calibration information is available in Lake Shore Document Number C2S001 –
Hall Generator Installation Instructions.
C2.0
THEORY OF OPERATION
The Hall effect was discovered by E. H. Hall in 1879. For nearly 70 years it remained a laboratory
curiosity. Finally, development of semiconductors brought Hall generators into the realm of the
practical.
A Hall generator is a solid state sensor which provides an output voltage proportional to magnetic flux
density. As implied by its name, this device relies on the Hall effect. The Hall effect is the
development of a voltage across a sheet of conductor when current is flowing and the conductor is
placed in a magnetic field. See Figure C-1.
Electrons (the majority carrier most often used in practice) “drift” in the conductor when under the
influence of an external driving electric field. When exposed to a magnetic field, these moving
charged particles experience a force perpendicular to both the velocity and magnetic field vectors.
This force causes the charging of the edges of the conductor, one side positive with respect to the
other. This edge charging sets up an electric field which exerts a force on the moving electrons equal
and opposite to that caused by the magnetic-field-related Lorentz force. The voltage potential across
the width of the conductor is called the Hall voltage. This Hall voltage can be utilized in practice by
attaching two electrical contacts to the sides of the conductor.
The Hall voltage can be given by the expression:
VH = γB B sin θ
where: VH = Hall voltage (mV)
γB = Magnetic sensitivity (mV/kG) (at a fixed current)
B = Magnetic field flux density (kilogauss)
θ = Angle between magnetic flux vector and the plane of Hall generator.
As can be seen from the formula, above, the Hall voltage varies with the angle of the sensed
magnetic field, reaching a maximum when the field is perpendicular to the plane of the Hall generator.
C2.1
ACTIVE AREA
The Hall generator assembly contains the sheet of semiconductor material to which the four contacts
are made. This entity is normally called a “Hall plate.” The Hall plate is, in its simplest form, a
rectangular shape of fixed length, width and thickness. Due to the shorting effect of the current supply
contacts, most of the sensitivity to magnetic fields is contained in an area approximated by a circle,
centered in the Hall plate, whose diameter is equal to the plate width. Thus, when the active area is
given, the circle as described above is the common estimation.
Hall Generator
C-1
Lake Shore Model 450 Gaussmeter User’s Manual
Ic (+)
(Red)
v
Conventional
Current
B
F
F = –e (v·B)
(force on electron)
VH (+)
(Blue)
+
–
+
–
+
–
+
–
v
B
e
VH (–)
(Clear or Yellow)
High Mobility III-V
Semiconductor
a) Indium arsenide
b) Gallium arsenide
Ic (–)
(Green or Black)
Figure C-1. Hall Generator Theory
C2.2
C-421-C-1.eps
ORIENTATION
Hall generators come in two main configurations, axial and transverse. Transverse devices are
generally thin and rectangular in shape. They are applied successfully in magnetic circuit gaps,
surface measurements and general open field measurements. Axial sensors are mostly cylindrical in
shape. Their applications include ring magnet center bore measurements, solenoids, surface field
detection and general field sensing.
+B
Transverse
+B
Axial
C-421-C-2.eps
Figure C-2. Axial and Transverse Configurations
C-2
Hall Generator
Lake Shore Model 450 Gaussmeter User’s Manual
C2.3
HANDLING
CAUTION: Care must be exercised when handling the Hall generator. The Hall
generator is very fragile. Stressing the Hall generator can alter its output. Any excess
force can easily break the Hall generator. Broken Hall generators are not repairable.
Hall Generators are very fragile and require delicate handling. The ceramic substrate used to produce
the Hall Generator is very brittle. Use the leads to move the Hall generator. Do not handle the
substrate. The strength of the lead-to-substrate bond is about 7 ounces, so avoid tension on the leads
and especially avoid bending them close to the substrate. The Hall Generator is also susceptible to
bending and thermal stresses.
C2.4
POLARITY
If the control current enters the red lead (with +IC connected to the positive terminal of the current
supply), and the magnetic field direction is as shown in Figure C-2, a positive Hall voltage will be
generated at the blue lead (+VH). Reversing either the current or the magnetic field will reverse the
output voltage.
C2.5
LEAD CONFIGURATIONS
All Hall generators (except Models HGCA-3020 and HGCT-3020) have 34 AWG solid copper with
poly-nylon insulation and have the same lead configuration as follows:
Red = +IC
Green = –IC
Blue = +VH
Clear = –VH
} Input (Control Current)
} Output (Hall Voltage)
The Model HGCA-3020 and HGCT-3020 Hall generators have 34 AWG stranded copper with Teflon®
insulation and have the following lead configuration:
Red = +IC
Black = –IC
Blue = +VH
Yellow = –VH
C3.0
} Input (Control Current)
} Output (Hall Voltage)
HALL GENERATOR GENERIC HOOKUP
The Hall voltage leads may also be connected directly to a readout instrument, such as a high
impedance voltmeter, or can be attached to electronic circuitry for amplification or conditioning.
Device signal levels will be in the range of microvolts to hundreds of millivolts. In this case, a separate
precision current source (Lake Shore Model 120CS or equivalent) is necessary. See Figure C-3.
CAUTION: The four Hall generator leads connect to four points on a sheet of
semiconductor material having different potentials. No two leads can be connected
together without adversely affecting operation. Therefore, the current source and the
output indicator cannot have a common connection, but must be isolated from each
other. One, the other, but not both, may be grounded.
CAUTION: Do not exceed the maximum continuous control current given in the
specifications.
The Hall generator input is not isolated from its output. In fact, impedance levels on the order of the
input resistance are all that generally exist between the two ports. To prevent erroneous current
paths, which can cause large error voltages, the current supply must be isolated from the output
display or the down stream electronics.
Hall Generator
C-3
Lake Shore Model 450 Gaussmeter User’s Manual
+IC
Hall Generator
IC
+VH
Model 120CS
Current Source
+
–VH
Digital Voltmeter
VH
RL
–
Load resistor required
for optimum linearity
(if specified)
–IC
C-421-C-3.eps
Figure C-3. Typical Hall Generator Hookup
C4.0
USING A HALL GENERATOR WITH THE MODEL 450
To hookup a Hall generator you must use a Lake Shore Model MCBL-6 Cable Assembly. The cable is
200 cm (79 inches) long with a DA-15 connector on one end and four leads on the other. The Hall
generator is a 4-lead device. The 4 leads are labeled +Ic (Red), –Ic (Black or Green), +VH (Blue), and
–VH (Yellow), corresponding to the 4 leads on all the Hall generators.
The Model 450 has an input impedance of 420 Ω. Therefore, the actual sensitivity at the gaussmeter
input will be less than the value given with the Hall generator due to drop in the leads and cable. This
fact is important because a sensitivity value is supposed to be loaded into the cable PROM to set
calibration. We recommend that the customer always check accuracy against a reference field rather
than use the sensitivity value sent with the bare Hall generator. Because Lake Shore has no control
of the conditions beyond the cable, the customer must accept responsibility for accuracy and
compatibility.
Finally, Manganin wire is not usually acceptable for cryogenic installations. The resistance of
Manganin wire is often too high. In cryogenic applications, Hall generators are normally connected
using twisted pairs of copper wire such as 34 gauge, Teflon insulated. There are two reasons for this:
1. The gaussmeter current source is normally limited in compliance voltage. The Model 450 should
not drive a load (Hall generator, Wires in cryostat, and probe cable) greater than 50 Ω. In fact, for
best performance, the load should be less than 30 Ω.
2. Because the Model 450 input impedance is 420 Ω, there is a voltage drop due to lead resistance
in series with the gaussmeter input. The Lake Shore Hall generator sensitivity given on the data
sheet is basically with no lead resistance. See Figure C-4.
The gaussmeter needs input sensitivity
between 0.5 to 1.5 mV/kG (HST) or
5.0 and 15 mV/kG (HSE) at its input
Gaussmeter
Input
Rcable
Rcust
420 Ω
Sensitivity at Gaussmeter input is
reduced by the lead/input voltage divider
VH
Rcable
Rcable = Lake Shore Model
MCBL-6 Cable Assembly
Rcust
Rcust = Customer
Supplied Leads
Figure C-4. Hall Generator Input Impedance
C-4
Hall Generator
Open Circuit
Sensitivity
C-421-C-4.eps
Hall Generator
Lake Shore Model 450 Gaussmeter User’s Manual
C5.0
SPECIFICATIONS
This section covers three types of Hall generators available from Lake Shore: HGCA & HGCT Series
Cryogenic Hall generators (Figures C-5 and C-6) with specifications (Table C-1), HGA Series Axial
Hall generators (Figures C-5 and C-7) with specifications (Table C-2), and HGT Series Transverse
Hall generators (Figures C-8 thru C-10) with specifications (Table C-3).
0.25 in.
diameter
9.5 in.
(min.)
0.20 in.
+B
0.20 in. diameter
0.105 in.
C-421-C-5.eps
Figure C-5. Axial Hall Generator HGA-3010, HGA-3030, and HGCA-3020 Dimensions
0.63 in.
9.5 in (min.)
(Lead Length)
0.180 in.
0.240 in.
(max.)
+B
Protective
Ceramic Case
0.043 in. (max.)
Center of
Active Area
C-421-C-6.eps
Figure C-6. Transverse Hall Generator HGT-3010, HGT-3030, and HGCT-3020 Dimensions
Table C-1. Cryogenic Hall Generator Specifications
Cryogenic
HGCA-3020
HGCT-3020
Description
Cryogenic axial; phenolic package
Cryogenic transverse; ceramic package
Active area (approximate)
0.030 inch diameter circle
0.040 inch diameter circle
Input resistance (approximate)
1 ohm
1 ohm
Output resistance (approximate)
1 ohm
1 ohm
Nominal control current (ICN)
100 mA
100 mA
Maximum continuous current
(non-heat sinked)
300 mA
300 mA
Magnetic sensitivity (IC = nominal control
current)
0.55 to 1.05 mV/kG
0.55 to 1.05 mV/kG
Maximum linearity error
(sensitivity vs. field)
±1.0% RDG (-30 to +30 kG)
±2.0% RDG (-150 to +150 kG)
±1.0% RDG (-30 to +30 kG)
±2.0% RDG (-150 to +150 kG)
Zero field offset voltage (IC = nominal
control current)
±200 µV (max.)
±200 µV (max.)
Operating temperature range
4.2 K to 375 K
4.2 K to 375 K
Mean temperature coefficient of magnetic
sensitivity
±0.01%/K (approx.)
±0.01%/K (approx.)
Mean temperature coefficient of offset (IC
= nominal control current)
±0.4 µV/K (max.)
±0.4 µV/K (max.)
Mean temperature coefficient of resistance
±0.6%/K (max.)
±0.6%/K (max.)
Leads
34 AWG copper w/Teflon insulation
34 AWG copper w/Teflon insulation
Hall Generator
C-5
Lake Shore Model 450 Gaussmeter User’s Manual
0.50 in.
9.5 in. (min.)
0.125 in.
Center of
Active Area
0.130 in. (max.)
+B
0.020 in.
(max.) over
Hall plate
0.028 in. (max.)
over leads
Figure C-7. Transverse Hall Generator HGT-1010 Dimensions
C-421-C-7.eps
Table C-2. Axial Hall Generator Specifications
Axial
HGA-3010
HGA-3030
Description
Instrumentation quality axial; low
temperature coefficient; phenolic
package
Instrumentation quality axial; phenolic
package
Active area (approximate)
0.030 inch diameter circle
0.030 inch diameter circle
Input resistance (approximate)
1 ohm
2 ohms
Output resistance (approximate)
1 ohm
2 ohms
Nominal control current (ICN)
100 mA
100 mA
Maximum continuous current (nonheat sinked)
300 mA
300 mA
Magnetic sensitivity (IC = nominal
control current)
0.55 to 1.05 mV/kG
6.0 to 10.0 mV/kG
Maximum linearity error (sensitivity
versus field)
±1% RDG (–30 to +30 kG)
±1.5% RDG (–100 to +100 kG)
±0.30% RDG (–10 to +10 kG)
±1.25% RDG (–30 to +30 kG)
Zero field offset voltage (IC = nominal
control current)
±50 µV (max.)
±75 µV (max.)
Operating temperature range
–40 to +100 °C
–40 to +100 °C
Mean temperature coefficient of
magnetic sensitivity
±0.005%/°C (max.)
–0.04%/°C (max.)
Mean temperature coefficient of offset
(IC = nominal control current)
±0.4 µV/°C (max.)
±0.3 µV/°C (max.)
Mean temperature coefficient of
resistance
±0.15%/°C (approx.)
+0.18%/°C (approx.)
Leads
34 AWG copper with poly-nylon
insulation
34 AWG copper with poly-nylon
insulation
C-6
Hall Generator
Lake Shore Model 450 Gaussmeter User’s Manual
Table C-3. Transverse Hall Generator Specifications
Transverse
HGT-1010
HGT-3010
HGT-3030
Description
General purpose
transverse; 0.020 inch thick
Instrumentation quality
transverse; low temperature
coefficient; ceramic
package
Instrumentation quality
transverse ceramic package
Active area (approximate)
0.040 inch diameter circle
0.040 inch diameter circle
0.040 inch diameter circle
Input resistance (approx.)
2 ohms
1 ohm
2 ohms
Output resistance (approx.)
2 ohms
1 ohm
2 ohms
Nominal control current
(ICN)
100 mA
100 mA
100 mA
Maximum continuous
current (non-heat sinked)
300 mA
300 mA
300 mA
Magnetic sensitivity (IC =
nominal control current)
7.5 to 12.5 mV/kG
0.55 to 1.05 mV/kG
6.0 to 10.0 mV/kG
Maximum linearity error
(sensitivity versus field)
±1.0% RDG
(-10 to 10 kG)
±1% RDG
(-30 to 30 kG)
±1.5% RDG
(-100 to 100 kG)
±0.30% RDG
(-10 to 10 kG)
±1.25% RDG
(-30 to 30 kG)
Zero field offset voltage (IC
= nominal control current)
±100 µV max.
±50 µV max.
±75 µV max.
Operating temperature
range
–40 to +100 °C
–40 to +100 °C
–40 to +100 °C
Mean temperature
coefficient of magnetic
sensitivity
–0.08%/°C max.
±0.005%/°C max.
–0.04%/°C max.
Mean temperature
coefficient of offset (IC =
nominal control current)
±1 µV/°C max.)
±0.4 µV/°C max.
±0.3 µV/°C
Mean temperature
coefficient of resistance
±0.18%/°C approx.
±0.15%/°C approx.
+0.18%/°C approx.
Leads
34 AWG copper with polynylon insulation.
34 AWG copper with polynylon insulation
34 AWG copper with polynylon insulation
Hall Generator
C-7
Lake Shore Model 450 Gaussmeter User’s Manual
C6.0
HALLCAL.EXE PROGRAM
The HALLCAL.EXE program was developed by Lake Shore Cryotronics, Inc. to allow the interfacing
of customer attached Hall generators to the Model 450 Gaussmeter. (Please refer to the Software
License Agreement behind the title page of this manual.) Because of the many intricacies involved
with proper calibration, the Customer must accept responsibility for the measurement accuracy.
Requirements:
•
Lake Shore Model 450 Gaussmeter (connected via RS-232 to the computer in the COM1 port).
•
Lake Shore Model MCBL-6 Cable Assembly.
•
IBM or compatible CPU.
•
Hall generator meeting the sensitivity ranges given below.
•
Calibration or sensitivity constant and serial number of the Hall generator.
1. Set the Lake Shore Model 450 Gaussmeter to 300 Baud. Refer Paragraph 3.11 of this User’s
Manual on how to set the Gaussmeter to communicate at 300 Baud.
2. Insert the 3.5-inch disk and type in the default drive (A: or B:).
3. Type in HALLCAL. This will execute the HALLCAL.EXE program.
4. The program will prompt for the Probe serial number. Any combination of 6 letters or number can
be entered. Press Enter when this is accomplished.
5. The program will prompt for the probe type (0 or 1).
Enter “0” for Hall generators with sensitivities between 5.5 and 10.5 mV/kG (@ 100 mA current).
Enter “1” for Hall generators with sensitivities between 0.55 and 1.05 mV/kG (@ 100 mA current).
6. The program will prompt for the “Calibration Constant.” Enter the magnetic sensitivity in mV/kG at
a control current of 100 mA. Remember to account for the 420 Ω input impedance of the
Gaussmeter when calculating the proper load resistor to install.
7. The program will display all the values entered along with designated F keys:
F1
F2
F3
F10
Esc
Probe Serial Number
Probe Type
Calibration Constant
Program Probe
Exit Program
ABC123
0
X.XXX
8. At this time, if any of the parameters need to be changed, just press the appropriate F key and
type in the new value. When everything appears correct, press F10 to program the probe.
9. It takes about 20 seconds to program the probe. After the probe is programmed, press the Esc
key to exit the program.
C-8
Hall Generator
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