MI 611-169
MI 611-169
Instruction
July 2005
873DO Series
Electrochemical Analyzers
for Dissolved Oxygen Measurement
Style C
MI 611-169 – July 2005
Contents
Figures................................................................................................................................... vii
Tables..................................................................................................................................... ix
1. Introduction ......................................................................................................................
Quick Start ...............................................................................................................................
Sensor Wiring ......................................................................................................................
Checking Factory Configurations .........................................................................................
Calibration ...........................................................................................................................
Looking for More Information .............................................................................................
General Description ..................................................................................................................
Instrument Features ..................................................................................................................
Enclosures ............................................................................................................................
Dual Alarms .........................................................................................................................
No Battery Backup Required ................................................................................................
Instrument Security Code ....................................................................................................
Hazardous Area Classification ..............................................................................................
Front Panel Display ..............................................................................................................
Front Panel Keypad ..............................................................................................................
Application Flexibility ..........................................................................................................
Storm Door Option .............................................................................................................
Analyzer Identification ..............................................................................................................
Standard Specifications .............................................................................................................
Product Safety Specifications .....................................................................................................
1
1
1
2
2
2
3
3
3
3
4
4
4
4
4
4
5
5
6
8
2. Installation ........................................................................................................................ 9
Mounting to a Panel – Plastic Enclosure 873DO-_ _ P ............................................................. 9
Mounting to a Panel - Metal Enclosure 873DO-_ _ W ........................................................... 10
Mounting to Pipe (Metal Enclosure Only) 873DO-_ _ Y ....................................................... 11
Mounting to Surface, Fixed Mount (Metal Enclosure Only) 873DO-_ _ X ............................ 12
Mounting to Surface, Movable Mount (Metal Enclosure Only) 873DO-_ _ Z ....................... 14
Wiring of Plastic Enclosure ..................................................................................................... 16
Wiring of Metal Enclosure ...................................................................................................... 16
3. Operation........................................................................................................................
Overview .................................................................................................................................
Display ....................................................................................................................................
Keypad ....................................................................................................................................
Operate Mode .........................................................................................................................
19
19
19
20
22
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MI 611-169 – July 2005
Contents
Temp Key ............................................................................................................................... 22
View Setup Entries .................................................................................................................. 22
4. Configuration..................................................................................................................
Overview .................................................................................................................................
Configure Mode ......................................................................................................................
Security Code ..........................................................................................................................
Unlocking Analyzer Using Security Code ................................................................................
Locking Analyzer Using Security Code ...................................................................................
Configuration Setup Entries ....................................................................................................
CELL Display and Output Configuration (CELL) .............................................................
Holding the Analog Output (HOLD) ................................................................................
Compensation and Damping (Cd) .....................................................................................
General Information About Alarms ....................................................................................
Wiring of Alarms ................................................................................................................
Setting Alarm Setpoints ......................................................................................................
Alarm 1 Control (AC1) ......................................................................................................
Alarm Timers (Att1, AFt1, and AdL1) ...............................................................................
Alarm 2 Control (AC2) ......................................................................................................
Alarm Timers (Att2, AFt2, and AdL2) ...............................................................................
User-Defined Upper Measurement Limit (UL) ..................................................................
User-Defined Lower Measurement Limit (LL) ...................................................................
User-Defined Upper Temperature Limit (UtL) ..................................................................
User-Defined Lower Temperature Limit (LtL) ...................................................................
Scaling the Analog Outputs ................................................................................................
Output #1's 100% Analog Value (H01) .............................................................................
Output #1's 0% Analog Value (L01) ..................................................................................
Output #2’s 100% Analog Value (H02) .............................................................................
Output #2's 0% Analog Value (L02) ..................................................................................
Basic Setup Entries ..................................................................................................................
Unlocking Basic Setup Entries (bL) ....................................................................................
Changing CELL Type (Ct) ................................................................................................
The Full Scale Range (FSC) ...............................................................................................
Setting Active or Electronic Zero (SErO) ...........................................................................
Setting Altitude ..................................................................................................................
Calibrating the Current Channel (Probe Calibration; PC) .................................................
Changing the Security Code (LCC) ...................................................................................
Calibrating the Temperature Circuitry (tEC1, tEC2) .........................................................
Changing the Analog Output .............................................................................................
To Reposition Jumpers .......................................................................................................
Using Sensor Diagnostics .......................................................................................................
Probe Diagnostics Enable (PdE) .........................................................................................
Diagnostic Learning Control (dLC) ...................................................................................
Fouling Diagnostic Tolerance (FOt) ...................................................................................
Membrane Cap Diagnostic Tolerance (CAt) .......................................................................
Bubble Diagnostic Tolerance (bUt) ....................................................................................
Diagnostic Timing (dt) .......................................................................................................
Diagnostic Off Window Timing (dOFF) ...........................................................................
iv
23
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23
23
24
24
24
26
27
28
30
30
31
31
33
36
38
40
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58
58
Contents
MI 611-169 – July 2005
Diagnostic On Window Timing (don) ............................................................................... 58
Fouling Diagnostic Lower Limit (FdLL) ............................................................................. 58
Drive Voltage (dr) ................................................................................................................... 58
5. Calibration ......................................................................................................................
Calibration of a Sensor on the 873DO - General Information ................................................
Startup Setup Parameters ........................................................................................................
Units, Zero, Altitude, and Calibration Type Setup .............................................................
Temperature CELL Factor (tCF1, tCF2) ...........................................................................
Air Calibration with Electronic Zero .......................................................................................
Solution Calibration with Electronic Zero ..............................................................................
Solution Calibration with Solution Zero .................................................................................
Oxygen Solubility Tables .........................................................................................................
59
59
60
60
61
62
64
65
66
6. Diagnostics......................................................................................................................
Using the 873DO Analyzer to Troubleshoot a Sensor or Analyzer Problem ............................
Additional Troubleshooting ....................................................................................................
Electronic Test for Verification of Operation of the 873DO Analyzer .....................................
Test with the CELL Simulator (Part No. BS806KM) .........................................................
Test with Resistors ..............................................................................................................
Error Codes .............................................................................................................................
Detachable Configuration Field Sheet .....................................................................................
67
67
68
70
70
70
73
75
7. User Notes.......................................................................................................................
Single Sensor Use ....................................................................................................................
CELL 1 Configuration .......................................................................................................
CELL 2 Configuration .......................................................................................................
Dual Sensor Use ......................................................................................................................
Redundant Sensor Operation ..................................................................................................
Backup Sensor Operation ........................................................................................................
CELL 1 Configuration .......................................................................................................
CELL 2 Configuration .......................................................................................................
77
77
77
78
79
80
81
81
82
8. Alarm Contact Maintenance............................................................................................ 83
WARRANTY ......................................................................................................................... 84
Index .................................................................................................................................... 85
v
MI 611-169 – July 2005
vi
Contents
Figures
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
Wiring of Metal Enclosure ...........................................................................................
Wiring of Plastic Enclosure ..........................................................................................
Front Panel Display and Keypad ..................................................................................
Data Label Location .....................................................................................................
Mounting to Panel - Plastic Enclosure ..........................................................................
Mounting to Panel - Metal Enclosure ...........................................................................
Metal Enclosure - Pipe Mounting ................................................................................
Metal Enclosure - Fixed Mount ...................................................................................
Metal Enclosure - Movable Mount ..............................................................................
Rear Panel Wiring - Plastic Enclosure ...........................................................................
Rear Panel Wiring - Metal Enclosure ...........................................................................
Model 873DO Keypad and Display .............................................................................
Possible Alarm Wiring and Configuration Choices .......................................................
ON/OFF relationship between Att1, AFt1, and AdL1 .................................................
Flow Diagram for Alarm Timer Logic ..........................................................................
ON/OFF Relationship between Att2, AFt2, and AdL2 ................................................
Flow Diagram for Alarm Timer Logic ..........................................................................
Current Source .............................................................................................................
Thermistor Temperature Simulation (Plastic Enclosure Shown) ..................................
Jumpers for Changing Analog Output .........................................................................
Analog Output Calibration (Metal Enclosure Shown) ..................................................
Test Resistors ................................................................................................................
Alarm Contact Reconditioning Circuit ........................................................................
1
2
5
5
9
10
11
13
15
16
17
20
30
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83
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MI 611-169 – July 2005
viii
Figures
Tables
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
Recommended Conduit and Fitting (Due to Internal Size Restraints) ..........................
Keypad Functions ........................................................................................................
Configuration Setup Entries .........................................................................................
Relationship of CELL Code to Alt Cel and mA Key Function .....................................
CELL Code – Display and Output Configuration .......................................................
HOLD Code - Hold Analog Output Values ................................................................
Cd Code – Compensation and Damping .....................................................................
AC1 Code - Alm 1 Configuration ................................................................................
Att1, AFt1, and AdL1 Time Codes ..............................................................................
AC2 Code - Alarm 2 Control .......................................................................................
Att2, AFt2, and AdL2 Time Codes ..............................................................................
Basic Setup Entry Selection ..........................................................................................
Jumper Positions for the Various Analog Outputs ........................................................
Determining Which Sensor is Erroring ........................................................................
Setup Parameters ..........................................................................................................
Diagnostics Error Codes ...............................................................................................
Probe Diagnostics Enable (PdE) ...................................................................................
Diagnostic Learn Modes ..............................................................................................
Oxygen Solubility Tables .............................................................................................
Error Codes ..................................................................................................................
Temperature vs. Resistance Values ...............................................................................
Troubleshooting Symptoms .........................................................................................
Error/Alarm Messages ..................................................................................................
18
21
25
26
27
28
29
33
34
37
39
43
51
56
56
56
57
57
66
67
68
69
74
ix
MI 611-169 – July 2005
x
Tables
1. Introduction
Quick Start
The purpose of this section is to outline the three basic steps to allow the user quick access to the
873DO Analyzer and 871DO-C dissolved oxygen probe for dissolved oxygen measurements. The
three steps are Wiring, Checking Factory Configuration, and Calibration. Details for these
procedures, as well as additional configuration choices, are found in the text of this manual.
Sensor Wiring
Wiring installation must comply with any existing local regulations.
The 873DO Analyzer is available in a plastic or metal enclosure. Follow the wiring instructions
for the type of enclosure you have. Additional information may be found on page 16 of this
manual. After wiring the sensor to the analyzer, allow the sensor to polarize at least a half hour
before calibrating (remove protective cap and allow sensor to stabilize while exposed to air).
WHT COAX 1
CLR
2
WHT
3
BLK
3A
GRN
4
RED
5
DARK GRN 6
WHT COAX
CLR
WHT
BLK
GRN
RED
DARK GRN
Figure 1. Wiring of Metal Enclosure
1
MI 611-169 – July 2005
1. Introduction
WHT COAX
CLR
WHT
BLK
GRN
RED
DARK GRN
DK
GRN
RED
GRN
BLK
WHT
CLR
COAX
WHT
DARK GRN
RED
GRN
BLK
WHT
CLR
WHT COAX
Figure 2. Wiring of Plastic Enclosure
Checking Factory Configurations
Refer to the analyzer label and Configuration Entries in Table 3, “Configuration Setup Entries,”
on page 25 and Table 12, “Basic Setup Entry Selection,” on page 43. There is space provided to
make any notations you wish in the last column of each table.
Calibration
Your analyzer was calibrated at the factory with a current source. Individual 871DO sensors do
not act as predictably and will require calibration with the analyzer. The analyzer is factory
configured for an air calibration with an electronic zero (this may be changed if desired). To verify
that the sensor is working properly, press and hold the Shift and the µA keys. The display will
show the sensor current in air. A stable current value between 6 and 8 µA is expected at
temperatures between 65° and 80°F. If the reading is stable, proceed with the calibration.
“Air Calibration with Electronic Zero” on page 62 outlines the steps of this simple calibration
technique.
Looking for More Information
For more detailed information, refer to the following sections of this manual:
For installation information, refer to “Installation” on page 9. For dimensional information, refer
to DP 611-163.
For detailed explanation of the controls and indicators, refer to “Operation” on page 19.
For detailed configuration instructions, refer to “Configuration” on page 23.
For detailed calibration instructions, refer to “Calibration” on page 59.
If you need additional help, please call the Invensys Foxboro Electrochemical Service Center at
1-508-549-4730 in the U.S.A., or call your local Invensys Foxboro representative.
2
1. Introduction
MI 611-169 – July 2005
General Description
The 873DO Analyzer in conjunction with an 871DO Sensor, measures, displays, and transmits
the concentration of dissolved oxygen in aqueous solutions. Its measurement display may be read
in either ppm, percent saturation, or percent air (%). Solution temperature is also measured by
the 873DO and is used for automatic temperature compensation and may be displayed whenever
the user wants.
The Analyzer provides an isolated output signal proportional to the measurement for transmission
to an external receiver. Both the plastic general purpose panel-mounted and the field-mounted
(metal enclosure) analyzers can transmit two output signals.
Instrument Features
Some of the features of the 873DO Electrochemical Analyzer are:
♦
Plastic General Purpose or Metal Field-Mounted Enclosure
♦
Dual Sensor Input
♦
Dual Alarms
♦
Dual Analog Outputs
♦
EEPROM Memory
♦
Instrument Security Code
♦
Hazardous Area Classification, Metal Enclosure Only
♦
Front Panel Display
♦
Front Panel Keypad
♦
Application Flexibility
♦
Storm Door Option
Enclosures
The plastic enclosure is intended for panel mounting in general purpose locations, and mounts in
1/4 DIN size panel cutout. It meets the enclosure ratings of NEMA 1, CSA Enclosure 1.
The metal enclosure is intended for field locations and may be either panel, pipe, or surface
mounted. The housing is extruded aluminum coated with a tough epoxy-based paint. The
enclosure is watertight, dusttight, and corrosion-resistant, meeting the enclosure rating of NEMA
4X, CSA Enclosure 4X, and IEC Degree of Protection IP-65, and fits in a 92 x 92 mm
(3.6 x 3.6 in) panel cutout (1/4 DIN size). The metal enclosure provides protection against radio
frequency interference (RFI) and electromagnetic interference (EMI).
Dual Alarms
Dual independent, Form C dry alarm contacts, rated 5 A noninductive 125 V ac/30 V dc, are
provided. The alarm status is alternately displayed with the measurement on the LED (lightemitting diode) display.
3
MI 611-169 – July 2005
1. Introduction
! CAUTION
When the contacts are used at signal levels of less than 20 W, contact function may
become unreliable over time due to the formation of an oxide layer on the contacts.
See “Alarm Contact Maintenance” on page 83.
No Battery Backup Required
Non-volatile EEPROM memory is employed to protect all operating parameters and calibration
data in the event of power interruptions.
Instrument Security Code
A combination code lock method, user configurable, provides protection of operational
parameters from accidental or unauthorized access.
Hazardous Area Classification
The field-mounted, epoxy-painted, aluminum enclosures are designed to meet the requirements
for Class I, Division 2, Groups A, B, C and D hazardous locations. See “Product Safety
Specifications” on page 8.
Front Panel Display
The instrument's display consists of a four-digit bank of red LEDs with decimal point, and an
illuminated legend area to the right of the LEDs (see Figure 3). The 14.2 mm (0.56 in) display
height provides visibility at a distance up to 6 m (20 ft) through a red protective window on the
front panel.
The measurement value is the normally displayed data. If other data is displayed due to prior
keypad operations, the display automatically defaults to the measurement value 10 seconds (called
“Timing Out”) after the last keypad depression.
If no fault or alarm conditions are detected in the instrument, the measurement value is steadily
displayed. If fault or alarm conditions are detected, the display alternates displaying the
measurement value and a fault or alarm message at a 1 second rate.
Front Panel Keypad
The instrument's front panel keypad consists of eight keys. Certain keys are for fixed functions;
and other keys are for split functions. The upper function (green legends) of a split function key is
actuated by pressing the shift key in conjunction with the split function key. Refer to Figure 3.
Application Flexibility
The 873 Analyzer offers application flexibility through its standard software package. The
software, run on the internal microprocessor, allows the user to define and set operating
parameters particular to his application. These parameters fall into four general categories:
Measurement Units, Alarm Configuration, Diagnostics, and Output Characterization. These
parameters are retained in the EEPROM nonvolatile memory. Following power interruptions, all
operating parameters are maintained.
4
1. Introduction
MI 611-169 – July 2005
Storm Door Option
This door is attached to the top front surface of the enclosure. It is used to prevent accidental or
inadvertent actuation of front panel controls, particularly in field mounting applications. The
transparent storm door allows viewing of the display and is hinged for easy access to the front
panel controls.
ANALYZER TYPE
ANALYZER TYPE
MEASUREMENT
MODEL DISPLAY
(4-DIGITS PLUS
DECIMAL POINT)
DUAL FUNCTION KEY
(PRESS SHIFT AND KEY
FOR TOP FUNCTION.
PRESS KEY ONLY FOR
LOWER FUNCTION)
Oxygen
873 Dissolved
Analyzer
MEASUREMENT
LEGEND UNITS
DISPLAY
uA
8.8.8.8.
Temp
Shift
Cal Hi
Alt Cel
Alm 1
Next
Cal Lo
Setup
Alm 2
Lock
%
Cel 2 ppm
uA
SINGLE FUNCTION KEY
(PRESS KEY ONLY)
Enter
Figure 3. Front Panel Display and Keypad
Analyzer Identification
A data label is located on the side surface of the enclosure. This data label provides Model
Number and other information pertinent to the particular Analyzer purchased. Refer to
Figure 4.
HARDWARE VERSION
SOFTWARE VERSION
Figure 4. Data Label Location
5
MI 611-169 – July 2005
1. Introduction
Standard Specifications
Supply Voltages
Supply Frequency
Output Signal
Ambient Temperature Limits
Measurement Ranges
Temperature Measurement Range
Temperature Compensation Range
Relative Humidity Limits
Accuracy of Analyzer
Analyzer Identification
Dimensions
Enclosure/Mounting Options
Approximate Mass
Plastic General Purpose Enclosure
Metal Field Enclosure (with Brackets)
Panel Mounting
Pipe Mounting
Fixed Surface Mounting
Movable Surface Mounting
Instrument Response (Analyzer Only)
Measurement Damping
6
–A 120 V ac
–B 220 V ac
–C 240 V ac
–E 24 V ac
–J 100 V ac
50 or 60, ±3 Hz
I
4 to 20 mA isolated
T 0 to 10 V dc isolated
E 0 to 20 mA isolated
–25 to +55°C (–13 to +131°F)
0 to 100.0% Oxygen Saturation
0 to 25.00% Oxygen in Air
0 to 100.0 ppm
0 to 100.0(no units)
–17 to +120°C (0 to 250°F) w/100 KΩ thermistor
0 to 50°C (32 to 122°F)
5 to 95%, noncondensing
±0.5% of upper range limit
Refer to Figure 4.
Plastic Enclosure 92(H) x 92(W) x 183(L) mm
Metal Enclosure 92(H) x 92(W) x 203(L) mm
–P Plastic General Purpose Panel Mount
–W Metal Field Panel Mount
–X Metal Field Surface Mount
–Y Metal Field Pipe Mount
–Z Metal Field Movable Surface Mount
0.68 kg (1.5 lb)
1.54 kg (3.4 lb)
2.31 kg (5.1 lb)
2.22 kg (4.9 lb)
3.13 kg (6.9 lb)
Two seconds maximum (when zero measurement
damping is selected in Configuration Code).
Temperature response is 15 seconds maximum.
Choice of 0, 10, 20, or 40 second, configurable from
keypad. Damping affects displayed parameters and
analog outputs.
1. Introduction
Alarms
Alarm Contacts
Alarm Indication
RFI Susceptibility
Plastic General Purpose Enclosure:
Metal Field Enclosure:
Electromagnetic Compatibility (EMC)
MI 611-169 – July 2005
• Two alarms configurable via keypad
• Individual set points continuously adjustable
0 to full scale via keypad
• Hysteresis selection for both alarms; 0 to 99% of
full scale value, configurable via keypad.
• Dual timers for both alarms, adjustable 0 to
99 minutes, configurable via keypad. Allows for
on/off control with delay. Timers can be set to
allow oxygen feed, then delay for oxygen concentration control.
Two independent, nonpowered Form C contacts,
rated 5 A noninductive, 125 V ac/30 V dc (minimum
current rating 1 A). Inductive loads can be driven
with external surge-absorbing devices installed across
contact terminations.
CAUTION: When the contacts are used at signal
levels of less than 20 W, contact function may become
unreliable over time due to the formation of an oxide
layer on the contacts. See “Alarm Contact
Maintenance” on page 83.
Alarm status alternately displayed with measurement
on LED display.
(When all sensor and power cables are enclosed in a
grounded conduit.)
< 0.5 V/m from 27 to 1000 MHz
10 V/m from 27 to 1000 MHz
The 873DO Analyzer, 220 V ac or 240 V ac systems,
with a metal enclosure complies with the
requirements of the European EMC Directive
89/336/EEC when the sensor cable, power cable, and
I/O cables are enclosed in rigid metal conduit. See
Table 1.
The analyzer with a plastic enclosure complies with
European EMC Directive 89/336/EEC when
mounted in a solid metal console or cabinet and the
I/O cables extending outside the console or cabinet
are enclosed in rigid metal conduit. See Table 1.
7
MI 611-169 – July 2005
1. Introduction
Product Safety Specifications
Testing Laboratory,
Types of Protection,
and Area Classification
FM for use in general purpose (ordinary)
locations.
FM nonincendive for use in Class I, II,
Division 2, groups A, B, C, D, F, and G,
hazardous locations.
CSA (Canada) for use in general purpose
(ordinary) locations.
CSA (Canada) suitable for use in Class I,
Division 2, Groups A, B, C, and D,
hazardous locations.
Application Conditions
Electrical
Safety Design
Code
---
FGZ
For instruments with metal enclosure
only.
Temperature Class T6.
24 V, 100 V, and 120 V ac (Supply
Option -Al, -E, -J) only.
For instruments with metal enclosure
only.
24 V, 100 V, and 120 V ac (Supply
Option -A, -E, -J) only.
Temperature Class T6.
FNZ
CGZ
CNZ
NOTE
The Analyzer has been designed to meet the electrical descriptions listed in the table
above. For detailed information on status of the agency approvals, contact Invensys
Foxboro.
! CAUTION
1. When replacing covers on the 873 metal case, use Loctite (Part No. S0106ML) on
the threads for the front cover and Lubriplate (Part No. X0114AT) on the threads for
the rear cover. Do not mix.
2. Exposure to some chemicals may degrade the sealing properties of Polybutylene
Teraethalate and Epoxy Magnacraft 276XAXH-24 used in relays K1 and K3. These
materials are sensitive to acetone, MEK, and acids. Periodically inspect relays K1 and
K3 for any degradation of properties and replace if degradation is found.
8
2. Installation
Mounting to a Panel – Plastic Enclosure 873DO-_ _ P
The plastic enclosure is mounted to a panel as described below (see Figure 5).
1. Size panel opening in accordance with dimensions specified on DP 611-162.
2. Insert spring clips on each side of Analyzer.
3. Insert Analyzer in panel opening until side spring clips engage on panel.
4. From rear of panel (and Analyzer), attach and tighten the top and bottom mounting
screws until Analyzer is securely held in place.
MOUNTING SCREWS (2)
SPRING
CLIPS(2)
Figure 5. Mounting to Panel - Plastic Enclosure
9
MI 611-169 – July 2005
2. Installation
Mounting to a Panel - Metal Enclosure 873DO-_ _ W
The metal enclosure can also be mounted to a panel. The procedure is as follows.
1. Refer to DP 611-162 for panel cutout data.
2. Make cutout in panel in accordance with DP 611-162.
3. Insert Analyzer through panel cutout and temporarily hold in place. (Rear bezel will
have to be removed for this procedure.)
4. From rear of panel, slide plastic clamp onto enclosure until clamp latches (two) snap
into two opposing slots on longitudinal edges of enclosure. See Figure 6.
5. Tighten screws (CW) on clamp latches until enclosure is secured to panel.
6. Reassemble rear bezel to enclosure using four screws.
REMOVABLE REAR BEZEL
CLAMP LATCH (2)
PANEL THICKNESS NOT
TO EXCEED 20 MM (0.8 IN)
PLASTIC CLAMP
PLASTIC CLAMP
SLOTS IN
LONGITUDINAL
EDGES OF
ENCLOSURE
CLAMP LATCH SCREW (2)
CLAMP LATCH (2)
Figure 6. Mounting to Panel - Metal Enclosure
10
2. Installation
MI 611-169 – July 2005
Mounting to Pipe (Metal Enclosure Only) 873DO-_ _ Y
1. Locate horizontal or vertical DN 50 or 2-inch pipe.
2. Assemble universal mounting as follows:
a. Place hex bolts (5) through spacer (3) into support bracket (2).
b. Slide nylon washers (11) over bolts (5).
c. Slide bolts through pipe mounting bracket (1) and fasten assembly tightly with
hardware designated 7, 6, and 13.
d. Attach pipe mounting bracket (1) to pipe using U-bolts (12) using hardware
designated 6, 7, and 13.
3. Slide Analyzer into support bracket and slide strap clamp (4) onto Analyzer. Using two
screws, nuts, and washers, attach strap clamp to support bracket to secure Analyzer.
4. Lift entire assembly of Step 3, and using two U-clamps, nuts, and washers, secure
mounting bracket to pipe.
MOUNTING
BRACKET
SPACER
U-CLAMP
STRAP
CLAMP
VERTICAL
DN50 OR
2-IN. PIPE
MOUNTING
BRACKET
0.312-18 NUTS (4)
0.190-32 SCREWS (2)
U-CLAMP
NOMINAL DN50 OR 2-IN.
PIPE. HORIZONTAL PIPE
SHOWN. TWO U-CLAMPS
ARE USED TO SECURE
BRACKET TO PIPE.
PIVOT BOLT; MOUNTED
ENCLOSURE CAN BE
ROTATED UP TO 60°
IN VERTICAL PLANE.
STRAP
CLAMP
Figure 7. Metal Enclosure - Pipe Mounting
11
MI 611-169 – July 2005
2. Installation
Mounting to Surface, Fixed Mount
(Metal Enclosure Only) 873DO-_ _ X
1. Locate mounting surface for Analyzer.
2. Referring to Figure 8, use mounting bracket as template for drilling four holes into
mounting surface. Notice that holes in mounting bracket are 8.74 mm (0.344 in) in
diameter. Do not attach mounting bracket to surface at this time.
3. Assemble universal mounting as follows:
a. Place hex bolts (5) through spacer (3) into support bracket (2).
b. Slide nylon washers (11) over bolts (5).
c. Slide bolts through universal mounting bracket (1) and fasten assembly together
with hardware designated 7, 6, and 12.
d. Attach universal mounting bracket (1) to wall.
4. Slide Analyzer into support bracket and slide strap clamp (4) onto Analyzer. Using
two screws, nuts, and washers, attach strap clamp to support bracket to secure
Analyzer.
5. Lift entire assembly of Step 4, align mounting bracket holes with mounting surface
holes, and use four bolts, nuts, and washers to attach mounting bracket to surface.
12
2. Installation
MI 611-169 – July 2005
SURFACE (REFERENCE)
SPACER
STRAP
CLAMP
MOUNTING
BRACKET
USER
SUPPLIED
SUPPORT
BRACKET
PIVOT BOLT: MOUNTED
ENCLOSURE CAN BE
ROTATED UP TO 60°
IN VERTICAL PLANE
STRAP
CLAMP
0.190-32 SCREWS (2)
Figure 8. Metal Enclosure - Fixed Mount
13
MI 611-169 – July 2005
2. Installation
Mounting to Surface, Movable Mount
(Metal Enclosure Only) 873DO-_ _ Z
1. Locate surface on which you wish to mount the Analyzer. Also refer to PL 611-016.
2. Referring to Figure 9, use wall bracket (12) as template for drilling four holes into
mounting surface. Notice that the holes in the wall bracket are 9.53 mm (0.375 in) in
diameter.
3. Attach wall bracket (12) to surface using four bolts, washers, and nuts.
4. Assemble universal mounting as follows:
a. Place hex bolts (5) through spacer (3) into support bracket (2).
b. Slide nylon washers (11) over bolts (5).
c. Slide bolts through universal mounting bracket (1) and fasten assembly finger
tight with hardware designated 9, 10, and 16.
5. Slide Analyzer into support bracket and slide strap clamp (4) onto Analyzer. Using
two screws, nuts, and washers, attach strap clamp to support bracket to secure
Analyzer.
6. Lift entire assembly of Step 5, align mounting bracket and wall bracket pivot bolt
holes, and then insert pivot bolt through wall and mounting bracket into nylon
washer and locking nut.
7. Rotate bracket and Analyzer assembly in horizontal plane to desired position and lock
in place using screw and washer.
14
2. Installation
MI 611-169 – July 2005
WALL BRACKET
PIVOT BOLT
(0.250 2 20) FOR
HORIZONTAL
PLANE ROTATION
SUPPORT
BRACKET
STRAP CLAMP
LOCK MOUNTING BRACKET IN PLACE
USING 0.190-32 SCREW AND WASHER
PIVOT
BOLT
SUPPORT
BRACKET
4 BOLTS
SUPPLIED
BY USER
PIVOT BOLT
(0.312-18) FOR
VERTICAL PLANE
ROTATION
NYLON WASHER
AND LOCK NUT
MOUNTING
BRACKET
STRAP
CLAMP
0.190-32 SCREWS (2)
Figure 9. Metal Enclosure - Movable Mount
15
MI 611-169 – July 2005
2. Installation
Wiring of Plastic Enclosure
Wiring installation must comply with any existing local regulations.
1. Remove optional rear cover assembly, if present.
2. Connect Alm 1 and 2 wires to TB3 as shown in Figure 10. Failsafe operation requires
connections be made between NC and C and the alarms to be configured active.
Refer to “General Information About Alarms” on page 30.
3. Connect wires from external circuit for Analyzer measurement output 1 to terminals
TB3(+) and TB3(–). Refer to Figure 10.
Connect wires from Analyzer measurement or temperature output 2 to terminals
TB4(+) and TB4(-).
4. Remove factory-installed jumper assembly from terminal block TB2 and TB5 and
discard.
5. Connect sensor wires to Analyzer terminal blocks TB2 and TB5 in accordance with
Figure 10. If a single sensor is used with this Analyzer, it may be wired to either sensor
input. See “User Notes” on page 77 for help with configuring the 873 for single or
dual sensor use.
6. Connect power wires to terminal block TB1 as shown in Figure 10.
7. Attach optional rear panel cover, if present.
WHT COAX
CLR
WHT
BLK
GRN
RED
DARK GRN
DK
GRN
RED
GRN
BLK
WHT
CLR
COAX
WHT
DARK GRN
RED
GRN
BLK
WHT
CLR
WHT COAX
Figure 10. Rear Panel Wiring - Plastic Enclosure
Wiring of Metal Enclosure
NOTE
1. Wiring installation must comply with any existing local regulations.
2. To maintain enclosure tightness such as NEMA 4X, CSA Enclosure 4X, or IEC
Degree of Protection IP-65, wiring methods and fittings appropriate to the
rating must be used. Table 1 lists the recommended parts.
16
2. Installation
MI 611-169 – July 2005
3. Alarm wires should run through the same conduit as the analog output wires.
Sensor wires and power wires should be run through separate conduits.
1. Remove back cover to access terminal/power board.
2. Connect Alarm 1 and 2 wires to TB3 as shown in Figure 11. Failsafe operation
requires connections to be made between contacts NC and C, and the alarms to be
configured active. Refer also to “General Information About Alarms” on page 30.
3. Connect wires from external circuits for Analyzer temperature or measurement
outputs to terminal TB4.
4. Connect sensor wires to Analyzer terminal block TB2 as shown in Figure 11.
If a single sensor is used with this Analyzer, it may be wired to either sensor input. See
“User Notes” on page 77 for help with configuring the 873 for single or dual sensor
use.
5. Connect power wires to terminal block TB1, as indicated in Figure 11. The earth
(ground) connection from the power cord should be connected to the ground stud
located in the bottom of the case. The stud grounds the instrument and is mandatory
for safe operation.
WHT COAX 1
CLR
2
WHT
3
BLK
3A
GRN
4
RED
5
DARK GRN 6
WHT COAX
CLR
WHT
BLK
GRN
RED
DARK GRN
Figure 11. Rear Panel Wiring - Metal Enclosure
17
MI 611-169 – July 2005
2. Installation
Table 1. Recommended Conduit and Fitting (Due to Internal Size Restraints)
Conduit
Rigid Metal
Semi-rigid Plastic
Semi-rigid Plastic, Metal Core
Flexible Plastic
1/2-inch Electrical Trade Size
T&B #LTC 050
Anaconda Type HC, 1/2-inch
T&B #EFC 050
Fitting
T&B* #370
T&B* #LT 50P or T&B #5362
T&B* #LT 50P or T&B #5362
T&B* #LT 50P or T&B #5362
*Thomas & Betts Corp., 1001 Frontier Road, Bridgewater, NJ 08807-0993
NOTE
It is recommended that sensor and interconnect cable be run in 1/2 inch conduit for
protection against moisture and mechanical damage. Do not run power or control
wiring in the same conduit.
18
3. Operation
Overview
The 873 functions in two modes, OPERATE and CONFIGURE (Setup).
In the OPERATE Mode, the instrument automatically displays its measurement and outputs
proportional analog signals. Also, while in the OPERATE Mode, a user may read all the
parameter settings and the solution temperature.
In the CONFIGURE Mode, any previously entered parameters may be modified. All 873
Analyzers are shipped configured, either with factory default settings or user defined parameters,
as specified.
To use either mode you must understand the functions of both the keypad and display.
Display
The instrument display, Figure 12, is presented in two parts, a measurement/settings display and
backlit engineering units. There are eight possible automatic measurement displays as follows:
♦
Measurement of CELL 1 expressed as % oxygen in air.
♦
Measurement of CELL 1 expressed in ppm.
♦
Measurement of CELL 1 expressed in % Saturation.
♦
Ratio between CELL 1 and CELL 2, expressed in %:
CELL
------------------2- × 100 = %
CELL 1
Example:
CELL 1 is measuring 5.0 ppm DO. CELL 2 is measuring 4.5 ppm DO. Ratio
would read 90.0%.
♦
Measurement of CELL 2 expressed as % oxygen in air.
♦
Measurement of CELL 2 expressed in ppm.
♦
Measurement of CELL 2 expressed in % Saturation.
♦
The difference between CELL 1 and CELL 2, expressed in % or ppm:
CELL 1 − CELL 2 = % or ppm
Example:
CELL 1 is measuring 100% saturated oxygen in water. CELL 2 is measuring
95.0% saturated oxygen in water. Difference would read 5.0%.
To read anything other than the measurement or to make a configuration or calibration change,
requires keypad manipulations.
19
MI 611-169 – July 2005
3. Operation
Keypad
The keypad, Figure 12, consists of eight keys, five of which are dual function keys. The white
lettered keys represent normal functions while the green lettered keys represent the alternate
function. To operate the white lettered function keys, just push them. To operate the green
lettered keys, the Shift key must first be pushed and held. All key functions are described in
Table 2.
DISPLAY
873
Dissolved Oxygen Analyzer
1.2
KEYPAD
Temp
Shift
Cal Hi
Alt Cel
Alm 1
Next
Cal Lo
Setup
Alm 2
Lock
µA
%
Cel
2
ppm
µA
Enter
Figure 12. Model 873DO Keypad and Display
20
ENGINEERING
UNITS ARE
BACKLIT. ONLY
THE ONE
CONFIGURED
IS VISIBLE.
3. Operation
MI 611-169 – July 2005
Table 2. Keypad Functions
Key
Function
Shift: Press and hold prior to pressing any dual-function key, to activate upper function on
dual function key. It is ignored when pressed with single function keys or when pressed
alone. However, holding the Shift key will delay the 10-second time-out to allow longer
viewing of a value or code.
Shift
µ A: Press key to display sensor current level (µA) without temperature correction. When
pressing key while in Ratio or Difference modes, the first depression will allow CELL 1’s
value to be viewed; subsequent pressing of the key before time out will allow CELL 2’s value
to be viewed.
Increment: Press to increase the value of the flickering number appearing on display. Each
depression causes the value to increase by one. When 9 or the highest number in the
configuration sequence is reached, the sequence repeats.
Temperature: Causes the process medium temperature or manually set value to appear on
the display. A rounded value with legend “C” or “F” shown alternates with a tenths place
digit. Manual temperature compensation (period shown after legend) may be altered in this
mode by entering a new value. The value may not be changed in the Automatic mode.
µA
Temp
Enter: Used to display the value or code of a setup entry. It is also used to select a parameter
or code by entering the value or code into memory.
Enter
Alternate CELL: Pressing key when CELL 1 is displayed shows Cel 2 value. Pressing key
when CELL 2 is displayed shows Cel 1 value. Pressing key once when Ratio or difference is
displayed (before timeout) shows Cel 1 value; pressing it a second time shows Cel 2 value.
Next: Used to select one of the four display digits similar to a cursor except that it causes the
digit to flicker. Also used to select the next entry choice of the setup function.
Setup: Used to select and access the analyzer’s configuration parameters and values.
Lock: Used to display the lock status and lock or unlock the analyzer.
Alt Cel
Next
Setup
Lock
Cal Lo
Cal Lo: Used to set the desired lower calibration level during bench calibration.
Alarm 2: Used to display the setpoint value for the relay associated with this alarm.
Alm 2
Cal Hi
Cal Hi: Used to set the desired upper calibration level during bench calibration.
Alarm 1: Used to display the setpoint level for the relay associated with this alarm.
Alm 1
NOTE
1. Pressing Next and ∆ simultaneously allows you to step backward through the
Setup program or digit place movement. Note, however, that you cannot reverse
number count by this procedure.
2. Pressing and holding Shift and Enter simultaneously overrides the 10-second
wait between Setup entries
21
MI 611-169 – July 2005
3. Operation
Operate Mode
Once the 873 Analyzer is powered, it is in the Operate Mode. The instrument first conducts a
self-diagnostic, then automatically displays the measurement.
While in the Operate Mode, the user may view the measurement, view the temperature, and view
all the parameter settings as configured in the Configuration Setup Entries and Basic Setup
Entries.
Temp Key
To view the process temperature, push Temp and the display changes from the dissolved oxygen
measurement to the process medium temperature or manually adjusted temperature.
From the measurement mode, when dual sensors are used, push Next and, while holding, press
Temp to display Cel 2’s process medium temperature or manually adjusted temperature. The
Cel 2 legend will be illuminated. The temperature cannot be changed by this procedure.
The display is a rounded whole number with the temperature units (C or F) alternating with
tenths of degrees. Once the 873 is unlocked (“Unlocking Analyzer Using Security Code” on
page 24), the Temp key, used in conjunction with the increment (∆) key, allows the temperature
to be changed from °C to °F or vice versa, as well as allowing the use of manual temperature
compensation at a given temperature (decimal shown after temperature). When Temp is pushed,
the process temperature is displayed on the readout. Pushing ∆ causes the display to sequence
from the displayed value through the following sequence example:
(1) 77.F
or
77.0
(2) 77.F.
or
77.0
(3) 25.C
or
25.0
(4) 25.C.
or
25.0
When the decimal point after the C or F is present, the measurement is temperature compensated
manually at the temperature displayed. To change that temperature, use Next and ∆ to display the
new value; then push Enter. Automatic temperature compensation cannot be adjusted by this
procedure. See “Startup Setup Parameters” on page 60. To return to automatic compensation,
sequence the display to remove the decimal point after C or F.
View Setup Entries
Setup Entries may be viewed at any time. To view any of the Setup Entries, follow the procedures
given in the Configuration Setup Entries or Basic Setup Entries section but do not “Unlock” the
instrument.
When viewing the Setup Entries, you may page through the parameters as rapidly as you wish
(Shift + Setup, Next one or more times). However, once Enter is pushed (Enter must be pushed
to read a parameter value), you must wait 10 seconds (value is displayed for 10 seconds) for the
parameter symbol to reappear. If the parameter value was not entered, pressing Shift and Enter
together will circumvent the 10 second wait between Setup entries. The parameter symbols also
appear for 10 seconds. If another key is not pushed in 10 seconds, the display defaults to the
measurement. This feature is called “timing out.” To avoid “timing out” on any display, push and
hold Shift.
To make changes to any Configuration Setup Parameter, refer to “Configuration” on page 23.
22
4. Configuration
Overview
This instrument is shipped with either factory settings (default values) or user defined settings, as
specified per Sales Order. Table 3, “Configuration Setup Entries,” on page 25 lists all the
parameters that are more frequently changed, and Table 12, “Basic Setup Entry Selection,” on
page 43 lists the parameters that are calibration oriented. Both tables list the displayed symbol,
the page number to read about the parameter, a description of the display, the factory default
value, and a space to write user values.
Configuration is the keypad manipulation of some parameters to make the Analyzer function to
the user's specifications. This section explains how to input and change specific data through the
keypad. Because reconfiguration may also involve wiring or jumper changes, care must be taken
to ensure that all three items are checked before the Analyzer is placed into service either at startup
or after any changes are made.
All 873 parameters are entered as 4-digit numerical codes. The code is chosen from tables shown
with each parameter. There are several parameters that are entered as direct 4-digit values.
Therefore, no table is supplied for those parameters.
Successful configuration requires four simple steps:
♦
Write down all your parameters in the spaces provided on the configuration tables.
♦
Unlock the instrument.
♦
Enter the 4-digit codes.
♦
Lock the instrument.
Configure Mode
The Configure Mode is protected through two levels of security, one level for “Configuration
Setup Entries” and a second for “Basic Setup Entries”. Any configuration change starts with
unlocking the instrument. Unlocking is accomplished by inputting a security code through the
keypad.
Security Code
There are two levels of security in the Analyzer; both use the same passcode. The first level of
security protects against unauthorized change of Temp, Alm 1, Alm 2, Cal Lo, Cal Hi, and all the
“Configuration Setup Entries” (of which there are 19) (refer to “Configuration Setup Entries” on
page 24). The second level of security protects the remaining 27 setup entries, called “Basic Setup
Entries,” 24 of which can be changed in the field (refer to “Basic Setup Entries” on page 43).
Any of the parameter codes or setpoints can be viewed when the Analyzer is in the locked state.
When displaying a parameter in the locked state, none of the digits flicker, and an attempt to
change the parameter results in the message Loc on the display.
23
MI 611-169 – July 2005
4. Configuration
When the unit is unlocked at the first level (see “Unlocking Analyzer Using Security Code” on
page 24), the unit will remain unlocked until a positive action is taken to lock the unit again (see
“Locking Analyzer Using Security Code” on page 24).
However, when the unit is unlocked using the bL entry at the second level of security (see
“Unlocking Basic Setup Entries (bL)” on page 44), it will remain unlocked only as long as any of
the Basic Setup Entries are being accessed. As soon as the Analyzer defaults to the current
measurement value, the second level of security automatically locks again, so an unlock procedure
is required to reaccess the Basic Setup Entries.
Unlocking Analyzer Using Security Code
1. Press Lock. Display will read Loc.
2. Press Next and then use the Next and increment (∆) keys until security code is
displayed (0800 from factory).
3. Press Enter. Analyzer will read uLoc, indicating unlocked state.
Locking Analyzer Using Security Code
1. Press Lock. Display will read uLoc.
2. Press Next and then use the Next and increment (∆) keys until security code is
displayed (0800 from factory).
3. Press Enter. Analyzer will read Loc, indicating locked state.
Configuration Setup Entries
The configuration setup entries consist of 19 parameters. These parameters are process oriented
and access to them is passcode protected. Table 3 lists each parameter (in the same sequence as
seen on the display), the page on which a complete description can be found, its applicable
symbol, factory default, and a space for recording your setting. Descriptions of each parameter are
given in the text that follows.
24
4. Configuration
MI 611-169 – July 2005
Table 3. Configuration Setup Entries
Displayed
Symbol
CELL
Hold
Cd
AC1
Att1
AFt1
AdL1
AC2
Att2
AFt2
AdL2
UL
LL
UtL
LtL
HO1
LO1
HO2
LO2
Reference
Factory
User
(Page No.)
Parameters and Values Accessed
Default Settings
26
Configuration of Display, Analog Outputs
1113
27
Holds and sets the Analog Output Value in Hold
0000
28
Compensation and Damping
0001
- Damping Factor
- Temperature Compensation
31
Alarm 1 Control
1403
- Measurement Selection
- Low/High/Instrument plus Passive/Active State
- % Hysteresis
38
Alarm 1 Trigger Timer
00.00
33
Alarm 1 Feed Time
00.00
33
Alarm 1 Delay Time
00.00
36
Alarm 2 Control
1203
- Measurement Selection
- Low/High/Instrument plus Passive/Active State
- % Hysteresis
38
Alarm 2 Trigger Timer
00.00
38
Alarm 2 Feed Time
00.00
38
Alarm 2 Delay Time
00.00
40
User-defined Upper Measurement Limit - Both CELLS per sales
order
40
User-defined Lower Measurement Limit - Both CELLS 0.00
41
User-defined Upper Temperature Limit - Both CELLS
100.0
41
User-defined Lower Temperature Limit - Both CELLS
0.00
42
100% Analog Output - Channel 1
per sales
order
42
0% Analog Output - Channel 1
0.00
42
100% Analog Output - Channel 2
100°C
42
0% Analog Output - Channel 2
0°C
To change any of the Configuration Setup parameters, use the following procedure:
1. Unlock Analyzer (see “Unlocking Analyzer Using Security Code” on page 24).
2. Press Shift and while holding, press Setup. Release fingers from both keys.
3. Press Next one or more times until the parameter to be changed is displayed.
4. Press Enter.
5. Use Next and ∆ until the desired code or value is displayed.
6. Press Enter.
7. Lock Analyzer (see “Locking Analyzer Using Security Code” on page 24).
NOTE
To prevent timeout at any time during this procedure, press and hold the Shift key.
25
MI 611-169 – July 2005
4. Configuration
CELL Display and Output Configuration (CELL)
The CELL 4-digit code selects the measurement displayed and configures the analog output
assignment. See Table 5.
Digit 1 Configuration:
When CELL 1 is displayed (first digit a 1), no CELL legend is displayed.
When CELL 2 is displayed (first digit a 2), the legend Cel 2 is displayed.
Ratio is displayed when the first digit of this code is 7. It is defined mathematically as
CELL
------------------2- x 100 (% legend lit.)
CELL 1
Difference is displayed when the first digit of this code is 9. It is defined mathematically as
CELL 1 – CELL 2 = Difference (in units you are using in your measurement)
When 2 is displayed as first digit of the code, and 0 is the second digit of the code, Alt Cel
displays CELL 1’s value. When 7 or 9 is used as the first digit of this code, Abso refers to CELL 1’s
value. Alt Cel will alternate between Cel 1 and Cel 2 with repeated pressings.
Table 4. Relationship of CELL Code to Alt Cel and µA Key Function
CELL Code Digits
One and Two
10
20
70
90
11
21
Press Alt Cel to display Press µA to display µA
values of:
value of:
CELL 2
CELL 1
CELL 1 and 2
CELL 1 and 2
-
CELL 1
CELL 2
CELL 1
CELL 1
CELL 1
CELL 2
Digit 2 Configuration:
SINGLE CELL OPERATION: The second digit of this code must be 1, if one of the two sensor
channels is not used. In single sensor operation, all pertinent parameters in other setup
configurations must also be configured to the CELL channel chosen, even if they are not used.
These include output selection (see digits 3 and 4 of CELL code), and Alarm Selection (AC1 and
AC2). If the alarms and analog output(s) will not be used, these must be set outside the operating
limits of the measurement, thus preventing error codes from occurring. In this mode, the Alt
CELL feature is not functional. See “User Notes” on page 77.
DUAL CELL OPERATION: The second digit of this code should be 0 when Ratio or Difference
modes are used, or whenever the user configures either alarm or output of both sensors. See User
Notes on page 77.
Digits 3 and 4 Configurations:
Two analog outputs are available on the 873DO. Signal assignments for these outputs are shown
in Table 5.
26
4. Configuration
MI 611-169 – July 2005
Possible combinations for the signal assignments of the two outputs include:
♦
Dissolved Oxygen Sensor 1 and Temperature Sensor 1
♦
DO Sensor 1 and DO Sensor 2
♦
Ratio and Temperature Sensor 1
♦
Difference and Dissolved Oxygen Sensor 1
For specific information on sensor setup, see “User Notes” on page 77.
Table 5. CELL Code – Display and Output Configuration
Digit 1
DISPLAY
1 - Cell 1
2 - Cell 2
7 - Ratio
9 - Difference
Digit 2
OPERATION
0 - Interrogate both
channels
1 - Ignore nonconfigured channel
Digit 3
Digit 4
OUTPUT 1
1 - Dissolved Oxygen Cell 1
2 - Dissolved Oxygen Cell 2
3 - Temp Cell 1
4 - Temp Cell 2
7 - Ratio
9 - Difference
OUTPUT 2
1 - Dissolved Oxygen Cell 1
2 - Dissolved Oxygen Cell 2
3 - Temp Cell 1
4 - Temp Cell 2
7 - Ratio
9 - Difference
Holding the Analog Output (HOLD)
The HOLD 4-digit code is used to freeze the output(s) at a particular value. The selections are
shown in Table 6. When the first digit of this code is 1, 2, or 3, the display flashes between the
word HOLD and the current measurement value. The outputs are set at a user selected value
corresponding to a % of the analog output range. The percentage is set by the last three digits of
the HOLD code. While in one of the HOLD modes, the Analyzer will continue to monitor and
display the measurement. The sensor may be cleaned or replaced, and the system calibrated, while
in this mode.
If an alarm is configured as a High, Low, or Instrument alarm (AC1 or AC2; second digit in code
is 1-6), the alarm status while in the HOLD mode may be selected by the first digit in the HOLD
code.
If , for instance, an alarm is configured as a HOLD alarm (AC1 or AC2; second digit is 7 or 8),
the alarm will trigger when the HOLD is activated. This feature allows a control room or alarm
device (light, bell, etc.) to know the Analyzer is in a HOLD mode, not a “RUN” mode. The
ALARM will be activated when HOLD is implemented when the first digit in the HOLD code is
1, 2, or 3.
Example 1: HOLD at a Percent of the Analog Output
For an analog output of 4 to 20 mA, 50% (050) will always equal 12 mA, and 0% will
equal 4 mA.
Or, to HOLD on the value being displayed at the present time, the value displayed must be
converted to a percent value by the following equation:
(Value
displayed - L01)- x 100
--------------------------------------------------------H01 - L01
27
MI 611-169 – July 2005
4. Configuration
Example 2: HOLD at the Value Presently Read on the Display
The presently displayed value for DO Sensor 1 is 6 ppm. H01 is set at 15 ppm, L01 is set
at 0.5 ppm. To hold the output at 6 ppm, the last two digits of HOLD must be 38.
6.0 - 0.55.5
---------------------x 100 = ---------- x 100 = 38
15.0 - 0.5
14.5
The HOLD code should read 1038, 2038, or 3038, as applicable. See “Output #1's
100% Analog Value (H01)” on page 42 and “Output #1's 0% Analog Value (L01)” on
page 42 for a description of H01 and L01.
If two outputs are present, both will HOLD at 38% (038) of their analog output ranges.
Table 6. HOLD Code - Hold Analog Output Values
Digit 1
0 = No HOLD
HOLD On, Analog Output on HOLD
1 - Alarms held in present state
2 - Alarms held in off state
3 - Alarms held in on state
Digits 2, 3, and 4
000 to 100% of Analog Output Range
Compensation and Damping (Cd)
Cd consists of a 4-digit code pertaining to measurement damping, and the type of ppm
temperature compensation desired. Damping time refers to the interval over which all
measurement readings are averaged. Damping affects dissolved oxygen and temperature
measurements as well as analog outputs. The ppm temperature compensation (digits 3 and 4) is
utilized when the FSC is in the 100 ppm Full Scale Range only (see “The Full Scale Range (FSC)”
on page 45. The function of digits 3 and 4 is ignored when FSC is set to other Full Scale Range
selections, although temperature compensation for changes in membrane oxygen transport
continue. The ppm temperature compensation is used during sensor calibration (“Calibration” on
page 59) and when measuring ppm in processes that change temperature. Table 7 lists the three
temperature compensation options. Temperature compensations applied are based upon Standard
Oxygen Solubility values. See Table 19 on page 66.
28
00
Configure the last two digits of the Cd code to 00 to provide temperature
compensation for oxygen solubility in fresh water. This setting must be
used for the air calibration technique; it allows the analyzer to relate the
current from the sensor to a 100% Oxygen saturated solution (air) and
convert this to a concentration (ppm) that would be observed in a
saturated fresh water sample (at the temperature the sensor/analyzer
reads).
01
Configure the last two digits of the Cd code to 01 to provide temperature
compensation for oxygen solubility in fresh water. This setting must be
used for a solution calibration technique, thus allowing the sensor current
to be related to a ppm value displayed on the analyzer. If the process
temperature changes after the calibration, the reading will be temperature
compensated to a concentration based on a fresh water temperature table.
4. Configuration
02
MI 611-169 – July 2005
Configure the last two digits of the Cd code to 02 to provide temperature
compensation for oxygen solubility in salt water. This setting must be used
for a solution calibration technique, thus allowing the sensor current to be
related to a ppm value displayed on the analyzer. If the process
temperature changes after the calibration, the reading will be temperature
compensated to a concentration based on a salt water temperature table.
Table 7. Cd Code – Compensation and Damping
Digit 1
Digit 2
DAMPING
0 - none
1 - 10 seconds
2 - 20 seconds
3 - 30 seconds
NOT USED
0
Digits 3 and 4
TEMPERATURE COMPENSATION
00 - % Saturation (for Air Cal)
01 - Pure Water (for Solution Cal)
02 - Salt Water (for Solution Cal)
29
MI 611-169 – July 2005
4. Configuration
General Information About Alarms
Two independent, Form C dry alarm contacts, rated at 5A noninductive, 125 V ac/30 V dc are
provided. The alarm status is alternately displayed with the measurement on the local LED
display on a 1 sec cycle. Alarms are configured using the AC1 or AC2 code as Low, High, Hold,
or instrument watchdog alarms, with active or passive relays, having a deadband or time delay.
! CAUTION
When the contacts are used at signal levels of less than 20 W, contact function may
become unreliable over time due to the formation of an oxide layer on the contacts.
See “Alarm Contact Maintenance” on page 83.
Wiring of Alarms
Alarm relay locations may be found in “Wiring of Plastic Enclosure” on page 16 and “Wiring of
Metal Enclosure” on page 16 of this instruction. See Figure 13.
Alarms relays in the 873DO Analyzer may be configured active or passive. An active relay is
energized when the analyzer is powered and the local display does not indicate an alarm state.
The external device may be wired to the analyzer in either of two ways:
♦
between NC and C, or
♦
between NO and C.
Figure 13 illustrates all possible wiring and configuration of these relays.
CONFIGURED PASSIVE: ENERGIZED IN ALARM CONDITION ONLY
SECOND DIGIT IN AC1
OR AC2 1, 3, 5, OR 7
NO
NO ALARM INDICATION
ON LOCAL DISPLAY
C
NC
NO
NO
C
ON
NC
NO
ON
C
C
ALARM INDICATION
ON LOCAL DISPLAY
NC
NC
CONFIGURED ACTIVE: NOT ENERGIZED IN ALARM STATE
SECOND DIGIT IN AC1
OR AC2 2, 4, 6, OR 8
NO
C
ON
NO ALARM INDICATION
ON LOCAL DISPLAY
NO
C
NC
NC
“FAILSAFE OPERATION”
NO
NO
C
NC
ALARM INDICATION
ON LOCAL DISPLAY
C
NC
Figure 13. Possible Alarm Wiring and Configuration Choices
30
ON
4. Configuration
MI 611-169 – July 2005
NOTE
1. Alarm setpoints will have to be reset if any changes are made to FSC.
2. Upon powering the Analyzer, the alarm operation is delayed for a time period
proportional to the damping time set in the Cd code (damping selection).
Alarms will remain “OFF” until the measurement has stabilized.
Check that the alarm (1 and 2) is configured as desired. Refer to “Alarm 1 Control (AC1)” on
page 31 and “Alarm 2 Control (AC2)” on page 36.
Setting Alarm Setpoints
NOTE
This procedure is relevant only when the alarms are configured as measurement
Low and/or High Alarms. When the alarms are configured as Watchdog or Hold
alarms, alarm level settings have no relevance.
1. Unlock Analyzer (see “Unlocking Analyzer Using Security Code” on page 24).
2. To set alarm 1, press Alm1. Then use Next and ∆ to achieve the desired value on the
display. Press Enter.
3. To set alarm 2, press Alm2. Then use Next and ∆ to achieve the desired value on the
display. Press Enter.
4. Lock Analyzer (see “Locking Analyzer Using Security Code” on page 24).
NOTE
If use of the alarms is not desired, set the Alm1 and Alm2 values outside of normal
measurement range.
Alarm 1 Control (AC1)
The AC1 4-digit code configures the alarm designated as “Alm 1”. See Table 8. There are three
configurable parameters associated with each alarm. The first digit of this code allows the alarm to
be configured to correspond to one of two alarm measurement selections. The second digit of this
code configures the alarm as a Measurement alarm, Instrument alarm, or Hold alarm.
When used as a measurement alarm, four configurations are possible. These are as a low passive or
active, or a high passive or active alarm, i.e., digit 2 is 1-4.
A low alarm relay will trip on decreasing measurement.
A high alarm relay will trip on increasing measurement.
Passive or active (failsafe) configurations are also chosen by this digit choice. In the active (failsafe)
configuration, a loss of power to the Analyzer will result in a change from active to passive relay
state, providing contact closure and an indication of a power problem. Correct wiring of the
contacts is necessary for true failsafe operation. For wiring information, refer to “Wiring of Plastic
Enclosure” on page 16 and “Wiring of Metal Enclosure” on page 16 of this document.
31
MI 611-169 – July 2005
4. Configuration
As an alternative to a measurement alarm, Alarm 1 has the option of being used as an Instrument
Alarm. In this “Watchdog” state, the alarm can communicate any diagnostic error present in the
system. When used as a diagnostic alarm, the alarm cannot be used as a conventional
measurement alarm. However, one of the configurable diagnostic parameters is “measurement
error,” so when programmed properly, alarm 1 can report either diagnostic or measurement
problems. Set digit 2 in this code as either 5 or 6, as applicable.
When alarm 1 is configured as a diagnostic error communicator, it will report any system
problem. It cannot, however, selectively report a given problem. The type of hardware/software
conditions that will cause an alarm include:
♦
A/D converter error
♦
EEPROM checksum error
♦
RAM error
♦
ROM error
♦
Processor task time error (watchdog timer)
In addition to these diagnostics, the user may program several temperature and measurement
error limits which, if exceeded, will cause an alarm condition. These programming options are
explained in “User-Defined Upper Measurement Limit (UL)” on page 40 and “User-Defined
Lower Temperature Limit (LtL)” on page 41.
NOTE
In addition to these diagnostics, special signals are provided from 871DO sensors
that are used to relate sensor diagnostic information for membrane coating,
breakage, or electrolyte problems. These diagnostics are not programmable to the
alarm contacts but are displayed locally only. See pages 55 through 58 for information
about programming these diagnostics.
Refer to the “Error Codes” on page 73, for identifying error messages.
Alarm 1 may also be configured and used as a HOLD alarm. When used as a HOLD alarm,
Alarm 1 cannot be used as a conventional measurement alarm. When Alarm 1 is configured as a
HOLD alarm (AC1; 2nd digit 7 or 8), the alarm will trigger when the HOLD is activated. This
feature will allow a control room or alarm device (light, bell, etc.) to know the Analyzer is in a
HOLD mode, not a “RUN” mode. The alarm will be activated when HOLD is implemented
when the first digit in the HOLD code is 1, 2, or 3. A HOLD alarm overrides the HOLD state
(on, off, current) normally enacted when the unit is placed in HOLD.
32
4. Configuration
MI 611-169 – July 2005
Finally, the alarm hysteresis (deadband) may be varied from 0 to 99% of the full scale
measurement value in increments of 1%. If the % legend is visible, hysteresis may be set from 0.0
to 9.9% concentration.
Table 8. AC1 Code - Alm 1 Configuration
Digit 1
MEASUREMENT SELECTION
1 - Dissolved Oxygen CELL 1
2 - Dissolved Oxygen CELL2
3 - Temp CELL 1
4 - Temp CELL 2
7 - % Ratio
9 - Difference
Digit 2
CONFIGURATION
1 = Low/Passive
2 = Low/Active
3 = High/Passive
4 = High/Active
5 = Instrument/Passive
6 = Instrument/Active
7 = HOLD/Passive
8 = HOLD/Active
Digits 3 and 4
HYSTERESIS
00 to 99% of Full Scale
0.0 to 9.9% (% mode)
Alarm Timers (Att1, AFt1, and AdL1)
There are three timers associated with the Alarm 1:
1. Att1 (Alarm 1 Trigger Time)
Programmable timer to prevent alarm from ever triggering for a time set by this
parameter.
2. AFt1 (Alarm 1 Feed Time)
Programmable timer to keep alarm ON for a time period set in this parameter after it
has been initially activated.
3. AdL1 (Alarm 1 Delay Time)
Programmable timer to keep the alarm OFF for the time set in this parameter after it
has been kept ON by parameter AFt1.
Each of these timers will be explained fully in the following paragraphs and their relationships
illustrated in Figure 14 and the flow diagram in Figure 15. If timed alarm actuation is utilized,
concentration hysteresis set in parameter AC1 is ignored.
Alarm 1 Trigger Timer (Att1) may be used with or without the other alarm timers (AFt1 and
AdL1). Att1 is used when Alarm 1 is configured as a Measurement alarm only (High or Low,
D.O. or Temperature). The purpose of this timer is to prevent the alarm from triggering, thus
allowing spurious transients, such as an air bubble or other glitch in the measurement from
tripping the alarm. After the timer has counted down, that alarm will activate only if the
measurement has remained in an alarm state during the entire trigger time. Att1 resets any time
the measurement passes through the alarm setpoint. Table 9 shows the code designation.
Alarm 1 Feed Time (AFt1) and Alarm 1 Delay Time (AdL1) may be used when Alarm 1 is
configured as a Measurement alarm for Dissolved Oxygen or Temperature. Alarm Feed Time 1
(AFt1) works in conjunction with Alarm Delay Time 1 (AdL1) to provide timed control over the
Alarm 1 relay (although AFt1 may be used without AdL1). These parameters should be used
together. Both parameters will take precedence over the alarm hysteresis set in AC1.
33
MI 611-169 – July 2005
4. Configuration
When Alarm 1 Feed Time (AFt1) is activated, Alarm 1 will stay ON for the amount of time set in
this function regardless of what the measurement value is in relationship to the alarm setpoint.
This means that Alarm 1 will remain ON even if the measurement goes out of alarm. Table 9
shows the code designation.
Example:
05.15 means 5 minutes, 9 seconds
Alarm1 Delay Time (AdL1) is activated by entering a time in the code parameter AdL1. On timeout of AFt1, the alarm will be deactivated for this time period. The alarm will not reactivate for
the time period set in AdL1 regardless of what the measurement value is in relation to setpoint.
After time-out of AdL1, the 873 reverts to a normal run mode. If the instrument has remained in
an alarm state for the entire time period (AFt1 + AdL1), the sequence of AFt1 and AdL1 repeats
itself. Table 9 shows the code designation.
Example:
20.50 means 20 minutes, 30 seconds
Table 9. Att1, AFt1, and AdL1 Time Codes
Digits 1 and 2
00 to 99 minutes
34
Digit 3
0 to 9 tenths of minutes
Digit 4
0 to 9 hundredths of minutes
4. Configuration
MI 611-169 – July 2005
TIME (MINUTES)
h
b
g
SETPOINT
i
MEASUREMENT
ON
f
c
a
i
ALARM RELAY
OFF
ON
b
d
h
OFF
Att1 (5 MIN.)
a
ON
e
OFF
AFt1 (15 MIN)
ON
e
OFF
AdL1 (20 MIN)
0
10
20
30
40
50
60
70
MINUTES
Figure 14. ON/OFF relationship between Att1, AFt1, and AdL1
NOTES: Example illustrated as High Alarm.
a. Measurement did not remain above setpoint for timer period set in Att1. Alarm
relay remains inactive. Att1 reset when measurement fell below alarm setpoint.
b. Measurement stays above alarm setpoint continuously for time set by Att1. After
time set in Att1, alarm relay becomes activated (c) for time period set by
parameter AFt1.
c. Timer Att1 reset when measurement fell below setpoint (d).
e. Upon time-out of AFt1, timer AdL1 will deactivate Alarm 1 relay (f ) for the time
period set by this parameter. The alarm remains deactivated even if measurement
(g) exceeds the alarm setpoint in this period of time.
h. The measurement is exceeding the alarm setpoint at the end of AdL1; the timer
Att1 resets, and alarm relay remains off. The measurement does not exceed the
alarm setpoint for the entire period Att1 (l), the alarm relay does not activate. If
the measurement had exceeded the setpoint for the entire sum of times (AFt1 +
AdL1), the feed timer (AFt1) would have been reactivated.
35
MI 611-169 – July 2005
No
4. Configuration
Measurement
exceed alarm
set point?
Measurement
Start
here
No
Yes
Att1
Meas.
Above alarm
setpoint continuously
for Att1
AFt1
Yes
?
AdL1
Did
Measurement
exceed alarm setpoint
continuously for
AFt1 + AdL1
Yes
?
No
Figure 15. Flow Diagram for Alarm Timer Logic
Alarm 2 Control (AC2)
The AC2 4-digit code configures the alarm designated as “Alm 2”. See Table 10. There are three
configurable parameters associated with each alarm. The first digit of this code allows the alarm to
be configured to correspond to one of six alarm measurement selections. The second digit of the
code configures the alarm as a Measurement alarm, Instrument alarm, or HOLD alarm.
When used as a measurement alarm, four configurations are possible. These are as a low passive or
active, or a high passive or active alarm. Set Digit 2 as 1-4, as applicable.
A low alarm relay will trip on decreasing measurement.
A high alarm relay will trip on increasing measurement.
Passive or active (failsafe) configurations are also chosen by this digit choice. In the active (failsafe)
configuration, a loss of power to the Analyzer will result in a change from active to passive relay
state, providing contact closure and an indication of a power problem. Correct wiring of the
contacts is necessary for true failsafe operation. For wiring information, consult page 16 and
page 16 of this document.
As an alternative to a measurement alarm, the alarm 2 has the option of being used as an
Instrument Alarm. In this “Watchdog” state, the alarm can communicate any diagnostic error
present in the system. When used as a diagnostic alarm, the alarm 2 cannot be used as a
conventional measurement alarm. However, one of the configurable diagnostic parameters is
“measurement error,” so when programmed properly, alarm 2 can report either diagnostic or
measurement problems. Set Digit 2 in this code as either 5 or 6, as applicable.
36
4. Configuration
MI 611-169 – July 2005
When the Alarm 2 is configured as a diagnostic error communicator, it will report any system
problem. It cannot, however, selectively report a given problem. The type of hardware/software
conditions which will cause an alarm include:
♦
A/D converter error
♦
EEPROM checksum error
♦
RAM error
♦
ROM error
♦
Processor task time error (watchdog timer)
In addition to these diagnostics, the user may program several temperature and measurement
error limits which, if exceeded, will cause an alarm condition. These programming options are
explained in“User-Defined Upper Measurement Limit (UL)” on page 40 through “User-Defined
Lower Temperature Limit (LtL)” on page 41.
NOTE
In addition to these diagnostics, diagnostic information for membrane coating,
breakage, or electrolyte problems in the 871DO is available. See pages 55 through
58 for programming these parameters. These diagnostics cannot be programmed to
the alarm relays. The sensor diagnostic error messages are only displayed locally.
Refer to the “Error Codes” on page 73 for identifying error messages.
Alarm 2 may also be configured and used as a HOLD alarm. When used as a HOLD alarm,
alarm 2 cannot be used as a conventional measurement alarm. When alarm 2 is configured as a
HOLD alarm (AC2; 2nd digit 7 or 8), the alarm will trigger when the HOLD is activated. This
feature will allow a control room or alarm device (light, bell, etc.) to know the Analyzer is in a
HOLD mode, not a “RUN” mode. The ALARM will be activated when HOLD is implemented
when the first digit in the HOLD code is 1, 2, or 3.
A HOLD alarm overrides the HOLD state (on, off, current) normally enacted when the unit is
placed in HOLD.
Finally, the alarm hysteresis (deadband) may be varied from 0 to 99% of the full scale
measurement value in increments of 1%. If the % legend is visible, hysteresis may be set from 0.0
to 9.9% concentration.
Table 10. AC2 Code - Alarm 2 Control
Digit 1
MEASUREMENT SELECTION
1 - Dissolved Oxygen CELL 1
2 - Dissolved Oxygen CELL 2
3 - Temp CELL 1
4 - Temp CELL 2
7 - % Ratio
9 - Difference
Digit 2
CONFIGURATION
1- Low/Passive
2 = Low/Active
3 = High/Passive
4 = High/Active
5 = Instrument/Passive
6 = Instrument/Active
7 = HOLD/Passive
8 = HOLD/Active
Digits 3 and 4
HYSTERESIS
00 to 99% of Full Scale
0.0 to 9.9 (% mode)
37
MI 611-169 – July 2005
4. Configuration
Alarm Timers (Att2, AFt2, and AdL2)
Three timers are associated with the Alarm 2:
1. Att2 (Alarm 2 Trigger Timer): Programmable timer to prevent alarm from ever
triggering for a time set by this parameter.
2. AFt2 (Alarm 2 Feed Time): Programmable timer to keep alarm ON for the time period
set in this parameter after it has been initially activated.
3. AdL2 (Alarm 2 Delay Time): Programmable timer to keep the alarm OFF for the time
set in this parameter after it has been kept ON by parameter AFt2.
Each of these timers is explained fully in the following paragraphs and their relationships
illustrated in Figure 16 and the flow diagram in Figure 17. If timed alarm actuation is utilized,
concentration hysteresis set in parameter AC2 is ignored.
Alarm 2 Trigger Timer (Att2) may be used with or without the other alarm timers (AFt2 and
AdL2). Att2 is used when Alarm 2 is configured as a Measurement alarm only (High or Low,
D.O. or Temperature). The purpose of this timer is to prevent the alarm from triggering, thus
allowing spurious transients, such as an air bubble or other glitch in the measurement, from
tripping the alarm. After the timer has counted down, that alarm will activate only if the
measurement has remained in an alarm state during the entire trigger time. Att2 resets whenever
the measurement passes through the alarm setpoint. Table 11 shows the code designation.
Alarm 2 Feed Time (AFt2) and Alarm 2 Delay Time (AdL2) may be used when Alarm 2 is
configured as a Measurement alarm for Dissolved Oxygen or Temperature. Alarm Feed Time 2
(AFt2) works in conjunction with Alarm Delay Time 2 (AdL2) to provide timed control over the
Alarm 2 relay (although AFt2 may be used without AdL2). These parameters should be used
together. Both parameters will take precedence over the alarm hysteresis set in AC2.
When Alarm 2 Feed Time (AFt2) is activated, Alarm 2 will stay ON for the amount of time set in
this function regardless of what the measurement value is in relationship to the alarm setpoint.
This means that Alarm 2 will remain ON even if the measurement goes out of alarm. Table 11
shows the code designation.
Example:
05.15 means 5 minutes, 9 seconds
Alarm 2 Delay Time (AdL2) is activated by entering a time in the code parameter AdL2. Upon
time-out of AFt2, the alarm will be deactivated for this time period. The alarm will not reactivate
for the time period set in AdL2 regardless of what the measurement value is in relation to
setpoint. After time-out of AdL2, the 873 reverts to a normal RUN mode. If the instrument has
remained in an alarm state for the entire time period (AFt2 + AdL2), the sequence of AFt2 and
AdL2 repeats itself. Table 11 shows the code designation.
Example:
20.50 means 20 minutes, 30 seconds
38
4. Configuration
MI 611-169 – July 2005
Table 11. Att2, AFt2, and AdL2 Time Codes
Digits 1 and 2
Digit 3
Digit 4
00 to 99 minutes
0 to 9 tenths of minutes
0 to 9 hundredths of minutes
SETPOINT
g
b
h
i
MEASUREMENT
ON
f
c
a
i
ALARM RELAY
OFF
ON
b
d
h
OFF
Att2 (5 MIN.)
a
ON
e
OFF
AFt2 (15 MIN)
ON
e
OFF
AdL2 (20 MIN)
0
10
20
30
40
50
60
70
MINUTES
Figure 16. ON/OFF Relationship between Att2, AFt2, and AdL2
NOTES: Example illustrated as Low alarm.
a. Measurement did not remain below setpoint for timer period set in Att2. Alarm
relay remains inactive. Att2 reset when measurement went above alarm setpoint.
b. Measurement stays below alarm setpoint continuously for time set by Att2. After
time set in Att2, alarm relay becomes activated (c) for time period set by
parameter AFt2.
c. Timer Att2 reset when measurement went above setpoint (d).
e. Upon time-out of AFt2, timer AdL2 will deactivate Alarm 2 relay (f ) for the time
period set by this parameter. The alarm remains deactivated even if measurement
(g) falls below the alarm setpoint in this period of time.
h. The measurement has transgressed the alarm setpoint at the end of AdL2; the
timer Att2 resets, and alarm relay remains off. The measurement does not remain
below the alarm setpoint for the entire period Att2 (l), the alarm relay does not
activate. If the measurement had remained below the setpoint for the entire sum
of times (AFt2 + AdL2), the feed timer (AFt2) would have been reactivated.
39
MI 611-169 – July 2005
No
4. Configuration
Measurement
below alarm
set point?
Measurement
No
Start
here
Yes
Att2
Meas.
Below alarm
set point continuously
for Att2?
AFt2
Yes
AdL2
Did
Measurement drop
below alarm set point
continuously for
AFt2 + AdL2?
Yes
No
Figure 17. Flow Diagram for Alarm Timer Logic
User-Defined Upper Measurement Limit (UL)
The UL parameter enables the user to define an upper measurement limit which, if exceeded,
gives an error message on the display (see “Error Codes” on page 73), and when used in
conjunction with either alarm configured as instrument (watchdog) alarm (AC1 or AC2 digit 2 is
5 or 6), provides a relay contact. The value set by this code defines the measurement limit for both
sensors.
By setting UL at a value that could never be achieved in a normal process situation, the activation
of a UL Alarm would indicate either a severe process upset or sensor miscalibration. The upper
limit on UL is 999.9 ppm or 999.9%.
NOTE
Invensys Foxboro preconfigures the UL value equal to the specified full scale
measurement per Sales Order.
User-Defined Lower Measurement Limit (LL)
The LL parameter is similar to the previously described UL parameter, except that it allows
programming of a lower measurement limit. A value of 0 is a good choice for LL but this
parameter may be set lower to prevent an alarm code from flashing. The lower limit on LL is
-99.9 (ppm, %). The value set by this parameter is related to both sensors.
NOTE
To make the display read -99.9, first display 099.9, then change the first digit to a
negative sign.
40
4. Configuration
MI 611-169 – July 2005
User-Defined Upper Temperature Limit (UtL)
This parameter enables the user to define an upper temperature measurement value which, if
exceeded, gives an error message on the display (“Error Codes” on page 73) and when used in
conjunction with the configurable alarms (AC1 or AC2 digit 2 is 5 or 6), provides a relay contact.
The UtL function may be used in a few different ways. First, the user may wish to alarm on high
process temperature. For example, in a supply line which is normally between 70°F and 90°F, the
user may wish to set UtL to 100°F to indicate a problem with the temperature control. Another
use of UtL is as a sensor diagnostic tool. If the thermistor in the 871DO Sensor develops a fault, it
may produce erroneous temperature readings at either extreme of the temperature scale. By
setting UtL at a temperature outside of any conceivable process temperature, an alarm will
indicate a problem with the 871DO Sensor thermistor. The upper limit on UtL is 200°C or
392°F. The value set for this parameter defines the limit for both sensors.
User-Defined Lower Temperature Limit (LtL)
This parameter is similar to the previously described UtL parameter, except that it allows
programming of a lower temperature measurement limit. The lower limit on LtL is –20°C or
-5°F. Invensys Foxboro preconfigures the LtL value to be 0°C. The value set for this parameter
defines the limit for both sensors.
NOTE
To make a minus sign appear, on the display requires a digit other than zero to be
present on the display.
Example:
To make the display read -20 C°, first display 020.°C, then change the first digit to a
negative sign.
Scaling the Analog Outputs
The 873DO Analyzer has dual isolated analog output signals, model code selected as 0 to 20 mA,
4 to 20 mA, or 0 to 10 V dc. For the current outputs, the maximum load is 800 Ω (18 volts
compliance). For the voltage output, the minimum load resistance is 1 kΩ. Each output signal is
linearly proportional to the measured variable. The dissolved oxygen output signal is linearly
proportional to the displayed variable, either ppm, percent saturation (%), percent oxygen in air
(%), difference or ratio.
NOTE
The analog outputs should be configured after the FSC and Cd parameters have
been set.
Example:
The user may be measuring water in the range of 80% to 100% saturation and may want
to assign the minimum analog output level (e.g., 4 mA) to a value of 80% saturated water
and the maximum analog output level (e.g., 20 mA) to a value of 100% saturated water.
The user may wish to “reverse” the analog output signal in some situations.
41
MI 611-169 – July 2005
4. Configuration
Example:
In the previous example, 20 mA may be assigned to the 100% saturated water and 4 mA
assigned to the 80% saturated water. No special procedures need to be followed to
accomplish a reverse output.
The maximum output span that should be set on the Analyzer is the FSC value. The minimum
output span that should be set on the Analyzer is 10% of the FSC value. Although it is physically
possible to set the Analyzer for a smaller span, loss of accuracy is possible. The analog output could
develop steps instead of following the measurement in a continuum as the last digit changes.
Output #1's 100% Analog Value (H01)
H01 enables the user to assign a measurement value to the maximum analog output (either 10 V
or 20 mA dc).
Example:
A user may wish to retransmit 4 to 20 mA dc over a dissolved oxygen concentration of 0.0
to 15 ppm. This parameter would then allow the assignment of the 20 mA dc output to a
value of 15 ppm. The FSC must be in ppm units, and Digit 3 of the CELL Code must
first be set to 1 or 2 to have this parameter have Dissolved Oxygen units. See page 26.
Invensys Foxboro preconfigures the H01 value to be equal to the specified full scale
measurement per sales order.
Output #1's 0% Analog Value (L01)
L01 enables the user to assign a measurement value to the minimum analog output (either 0 V,
0 mA, or 4 mA dc). In the example above, the user would assign the minimum analog output of
4 mA dc to a value of 0.0 ppm, provided FSC has units of ppm and Digit 3 of CELL is 1 or 2. See
“CELL Display and Output Configuration (CELL)” on page 26. Invensys Foxboro preconfigures
the 0% value to be equal to 0 (% or ppm, as applicable).
Output #2’s 100% Analog Value (H02)
H02 configures the second output to 100% of the analog output. The parameter is similar to
H01. H02 value ties to CELL Code Digit 4.
Example:
Output 2 has been configured to correspond to temperature of CELL 1 (CELL Code
1113). You wish to have 20 mA correspond to 40°C. Once in H02 mode, use Next and ∆
to display 40°C. The correct units will appear if CELL is configured correctly. Press Enter.
Output #2's 0% Analog Value (L02)
L02 configures the second output to 0% of the analog output. This parameter is similar to L01.
L02 value ties to CELL Code Digit 4.
Example:
Output 2 has been configured to correspond to the temperature transducer of CELL 1
(CELL Code 1113). You wish to have 4 mA correspond to 0°C. Once in L02 mode, use
Next and ∆ to display 0°C. The correct units will appear if CELL is configured properly.
Press Enter.
42
4. Configuration
MI 611-169 – July 2005
Basic Setup Entries
The Basic Setup entries consist of 25 configurable parameters. These parameters are calibration
oriented and access to them has two levels of passcode protection. Changes to most of these
parameters require the analyzer to be recalibrated. DO NOT make any changes before reading the
following text for each parameter.
Table 12 lists each parameter, with its applicable symbol, in the same sequence as seen on the
display. Procedures that use these parameters are: Unlocking Basic Setup Entries, Changing Ct,
Selecting the Full Scale Range, Changing the Full Scale Range, Setting Active or Electronic Zero,
Setting Altitude, Calibrating the Current Channel, Changing the Security Code, Calibrating the
Temperature Circuitry, Changing the Analog Output, and Using Sensor Diagnostics.
Table 12. Basic Setup Entry Selection
Display
Symbol
bL
Ct
FSC
SEr0
ALt
PC
LCC
tCF1
tEC1
tCF2
tEC2
LC01
HC01
LC02
HC02
PdE
dLC
FOt
CAt
bUt
dt
dOFF
don
FdLL
dr
Section
44
44
45
46
46
47
49
49
49
49
49
50
50
50
50
57
57
57
57
58
58
58
58
58
58
Parameter and Value Accessed46
Basic Setup Lock Control
Sensor CELL Type
Full Scale Value
Zero Calibration
Altitude Calibration
Probe Calibration
Lock Change Code
Temperature CELL Factor CELL 1
Temperature Electronics Calibration CELL 1
Temperature CELL Factor CELL 2
Temperature Electronics Calibration CELL 2
Low Calibration Analog Output 1
High Calibration Analog Output 1
Low Calibration Analog Output 2
High Calibration Analog Output 2
Probe Diagnostic Enable
Diagnostic Learning Control
Fouling Diagnostic Tolerance
Membrane Cap Diagnostic Tolerance
Bubble Diagnostic Tolerance
Diagnostic Interval Timing
Diagnostic Off Window Timing
Diagnostic On Window Timing
Fouling Diagnostic Lower Limit
Drive Voltage Setting
Factory
Default
0800
0004
100 ppm
0001
0000
0000
0800
25.00
25.00
25.00
25.00
00.00
100.0
00.00
100.0
0000
0000
0050
0020
0020
0060
2.000
2.000
001.0 µA
00.70
User
Settings
Display Symbols Sft, SOH, and SOL appear in the display but are not configurable.
43
MI 611-169 – July 2005
4. Configuration
Unlocking Basic Setup Entries (bL)
To change any of the Basic Setup Entries, use the following procedure.
NOTE
To avoid “timing out” on any display, push and hold Shift.
1. Unlock Analyzer at the first security level (see “Unlocking Analyzer Using Security
Code” on page 24).
2. Press Shift and while holding, press Setup. Release finger from both keys.
3. Press Next nineteen times until bL is displayed; press Enter , LOC appears.
4. Press Next.
5. Use Next and ∆ until security code is displayed (0800 from factory).
6. Press Enter. ULOC appears on the display.
7. When display returns to bL, press Next one or more times until parameter to be
changed appears on the display. Press Enter.
8. Use Next and ∆ until the desired value is displayed. Press Enter.
9. When display defaults to the current measurement value, the analyzer is automatically
locked at the second level (bL) of security.
10. Lock Analyzer (see “Locking Analyzer Using Security Code” on page 24).
Changing CELL Type (Ct)
The code Ct electronically configures the 873DO analyzer to apply a polarizing voltage to the
correct inputs of the type of sensor connected. When two sensors are connected to a single
analyzer both sensors must be the same type, as the same CELL type configuration will be applied
to both sensors. The sensors will have to be recalibrated after changing Ct. See the section on
Calibration on page 59.
Procedure to Change Ct:
Unlock bL by following procedure in “Unlocking Basic Setup Entries (bL)” on page 44. When
the display returns to bL after the ULOC code, press Next once. The Ct code will be displayed.
Press Enter. The present Ct code will be displayed. The Ct code is changed by depressing ∆ . The
code alternates between 0002, 0003, and 0004 with repeated pressing of ∆ . All other entries
result in ERR being displayed upon attempting to Enter them. The analyzer then defaults to the
last acceptable entry. When the correct value is displayed, press Enter.
The 873DO Analyzer was primarily designed to be used with 871DO sensors using a
3-electrode potentiostat configuration and diagnostics. The Ct used with 871DO sensors is 0004.
Ct should be 0003 when 3-electrode CELLS (without diagnostics) are used. Ct should be set to
0002 for 2-electrode sensor use. In the Ct = 0002 configuration, the voltage required for
polarization is applied between the working and auxiliary electrodes, and the current generated is
drawn through the auxiliary electrode. In this case, the auxiliary serves as a reference and anode in
the circuit. In the Ct = 0003 or 0004 configuration, the polarization voltage applied to the
working electrode is relative to the reference electrode, but the current generated is drawn through
the auxiliary electrode.
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4. Configuration
MI 611-169 – July 2005
The Full Scale Range (FSC)
Selecting the Full Scale Range (FSC)
The FSC parameter allows the user to select one of several possible ranges to monitor the process.
The FSC range choices are:
100.0 ppm
100.0%
25.0%
100.0
(mg/l)
(percent saturation)
(percent of air)
(no units)
The 100.0 ppm FSC requires additional temperature compensation be set via the Cd Setup
parameter (see “Compensation and Damping (Cd)” on page 28). When used in this mode, the
legend ppm is illuminated, and the analyzer reads out in these concentration units with either
fresh or salt water oxygen solubility temperature corrections applied.
When the FSC 100.0 Percent Saturation is chosen, the % legend is illuminated. This scale is
indistinguishable from the % air FSC or Ratio measurement from the front display. Temperature
corrections are applied for the composite membrane characteristics only.
The FSC 25.0 Percent Air is used to compare the dissolved oxygen reading with the content of the
air. Dry air at 1 Atmosphere consists of 20.95% oxygen, so measurements in this mode are all
displayed as a percentage of air. Temperature corrections are applied for the composite membrane
characteristics only.
The fourth FSC is 100.0 with no illuminated units. The only temperature corrections applied are
for the composite membrane characteristics. The sensor may be calibrated in any units the user
wishes. Additional temperature corrections may be applied by the user via a user supplied
computer system.
The following rules are applicable to all FSCs chosen:
♦
When two sensors are connected to a single analyzer, both sensors must utilize the
same FSC.
♦
FSC should be chosen and entered before any Configuration Setup Entries are set.
♦
After changing FSC, Configuration Setup Entries must be checked and altered.
♦
Pressing Enter in FSC mode (even if range was not changed) requires the unit to be
recalibrated before use. If the range is set at the desired FSC, allow unit to time out.
Do not press Enter.
♦
Invensys Foxboro preconfigures the FSC value to 100 ppm.
Changing the Full Scale Range
The procedure to change FSC is as follows.
1. Unlock Analyzer (see “Unlocking Analyzer Using Security Code” on page 24).
2. Press Shift and while holding, press Setup. Release fingers from both keys.
3. Press Next several times until the code bL (Basic Setup Lock) is displayed (bL will be
the twentieth message to be displayed).
45
MI 611-169 – July 2005
4. Configuration
4. Press Enter, then use Next and ∆ until personal security code is displayed (0800 from
factory). Press Enter.
5. When display returns to bL, press Next twice. The code FSC (Full Scale Range
Change) will be displayed.
6. Press Enter. The present full scale range will be displayed.
! CAUTION
If this is your desired FSC, allow unit to time out. Do Not Press Enter. Entering any
FSC causes Er 4 to flash on the display, necessitating a calibration.
7. Press ∆ until the desired range is displayed. Press Enter.
NOTE
Calibration is required after full scale range is changed. Error code Er 4 flashes until
calibration is accomplished.
Refer to the section on Calibration on page 59.
Setting Active or Electronic Zero (SErO)
The function of this parameter is to allow the user a choice in the way Cal Lo is set during a
standardization.
When the Setup parameter SErO is 0000, the Analyzer requires and utilizes the actual current
output of the sensor in zero oxygen to calibrate Cal Lo. The sensor has to be placed in a solution
void of oxygen, or in an oxygen free gas (nitrogen) for the Cal Lo value to be calibrated.
When the Setup parameter SErO is 0001, the Analyzer uses an electronic value for zero current,
irrespective of the sensor's residual current at zero oxygen, to set the Cal Lo during calibration.
This is typically a good approximation for the 871DO sensor's output in a zero oxygen situation.
The residual currents found on functioning sensors in zero oxygen situations are very low, and this
approach greatly simplifies the calibration procedure.
Procedure to Change SErO:
Unlock bL by following procedure in “Unlocking Basic Setup Entries (bL)” on page 44. When
the display returns to bL after the ULOC code, press Next three times. The SErO code will be
displayed. Press Enter. The present SErO code will be displayed. The SErO code is changed by
depressing ∆ . The code alternates between 0000, and 0001 with repeated pressing of ∆ . When
the correct value is displayed, press Enter.
Invensys Foxboro preconfigures the 873DO analyzer to read 0001 for this parameter. Sensors will
require recalibration after changing this parameter. See “Calibration” on page 59.
Setting Altitude
The function of the parameter Alt is to set the altitude at which the 873DO and 871DO sensor
will be physically located, in order for air calibration in ppm to be compensated correctly. The
number should be entered as feet above or below sea level. The range that this parameter may be
set is –999 to 9999 feet.
46
4. Configuration
MI 611-169 – July 2005
Invensys Foxboro preconfigures the 873DO analyzer to read 0000 for this parameter unless
ordered differently. Sensors may require recalibration after changing this parameter. See the
section on Calibration on page 59.
Calibrating the Current Channel (Probe Calibration; PC)
The parameter PC allows current calibration to be performed on the 873DO analyzer.
NOTE
This procedure does not deal with analog output calibrations. The sensor current is
read when the user depresses Shift and µA keys.
! WARNING
This procedure is performed at the factory and should not have to be repeated. Care
must be taken to ensure that the precision current source does not exceed 10 V dc on
the output terminals when current is demanded, and that no load exists on the source.
Hint:
If you wish to verify current values, short terminals 5 and 6, then install known resistors between
terminals 3A and 5 and calculate the expected current reading according to Ohm's Law; E=IR.
The factory set applied voltage is .700 V.
.7 V
------------------------- = Current in Amp
Resistance
10–6 Amp = l µA. “Test with Resistors” on page 70 contains the entire procedure.
Required:
Precision current source (0 to 20 µA). See Figure 18
.
Figure 18. Current Source
Procedure:
1. Disconnect sensor leads from terminals 2 and 3A of both sensors.
2. Connect current source + to 3A and – to 2 (ground).
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MI 611-169 – July 2005
4. Configuration
3. Unlock Analyzer using security code (see “Unlocking Analyzer Using Security Code”
on page 24).
4. Press Shift and while holding press Setup. Release fingers from both keys.
5. Press Next twice to display Cd; press Enter.
6. Press Next and ∆ until the display reads 0000. Press Enter.
7. When the display returns to Cd, press Next several times until the code bL is
displayed. Press Enter.
8. Unlock bL by following procedure in “Unlocking Basic Setup Entries (bL)” on
page 44.
9. When the display returns to bL after the ULOC code, press Next three times. The
SErO code will be displayed. Press Enter. The present SErO code will be displayed.
The SErO code is changed by depressing ∆ . The code alternates between 0000, and
0001 with repeated pressing of ∆ .
10. When 0000 is displayed, press Enter.
11. When the display returns to SErO, press Next two times to display the parameter PC.
Press Enter.
12. Use Next and ∆ until the display reads 0001. Press Enter.
13. Set the current source for 0 µA.
14. Press Shift and while holding press Cal Lo. Release fingers from both keys.
15. Use Next and ∆ until the display reads 000.0. Press Enter.
16. Set the current source to 20 µA.
17. Press Shift and while holding, press Cal Hi. Release fingers from both keys.
18. Use Next and ∆ until the display reads 20.0. Press Enter.
19. Press Shift and while holding, press Setup. Release fingers from both keys.
20. Unlock bL by following procedure in “Unlocking Basic Setup Entries (bL)” on
page 44. When the display returns to bL after the ULOC code, press Next three
times. The SErO code will be displayed. Press Enter. Set this parameter to the desired
value (see “Setting Active or Electronic Zero (SErO)” on page 46). Press Enter.
21. When the display returns to SErO, press Next two times to display the parameter PC.
Press Enter.
22. Use Next and ∆ until the display reads 0000. Press Enter.
23. Change Cd code to desired values. See “Compensation and Damping (Cd)” on
page 28.
24. Disconnect current source and reconnect sensor. Sensor servicing and/or
standardization may be required. Consult sensor instructions or the section on
Calibration on page 59.
25. Lock Analyzer using security code (see “Locking Analyzer Using Security Code” on
page 24).
48
4. Configuration
MI 611-169 – July 2005
Changing the Security Code (LCC)
The following procedure is used to change the security code to another 4-digit code.
NOTE
If existing security code is forgotten, a new security code cannot be entered using
this procedure. In this case, contact Invensys Foxboro.
1. Leave power on.
2. Press Lock. Display will show either Loc or uLoc.
3. If uLoc is displayed, proceed to Step 4.
If Loc is displayed, unlock the analyzer using “Unlocking Analyzer Using Security
Code” on page 24. Display will read uLoc.
4. Press Shift and while holding, press Setup. Release fingers from both keys.
5. Press Next several times until the code bL (Basic Setup Lock) is displayed. Press Enter.
6. Then use Next and ∆ until existing security code is displayed (0800 from factory).
7. Press Enter.
8. When display returns to bL, press Next several times until the code LCC (Lock Code
Change) is displayed.
9. Press Enter, then use the Next and increment ( ∆ ) keys until new desired security
code is displayed.
10. Press Enter. The new code will have to be used on all future entries.
11. Lock the Analyzer using the procedures explained in “Locking Analyzer Using
Security Code” on page 24.
Calibrating the Temperature Circuitry (tEC1, tEC2)
Temperature Electronics Calibration for the 873DO Analyzer is performed at the factory. It
should not be necessary to perform these procedures in the field unless:
1. You suspect a problem with the temperature calibration.
2. You wish to verify temperature electronics calibration.
This procedure only calibrates the analyzer. To compensate the temperature reading
for sensor cable length, see “Determining tCF” on page 61 and “Entering a tCF
Value” on page 62.
Required: Two 100 kΩ precision resistors.
Procedure for Thermistor Temperature Electronic Calibration:
1. Disconnect sensor lead connections 1 and 2 from TB2 and TB5.
2. Connect a precision 100 kΩ resistor between the sensor terminals: 1 and 2 on TB2
and TB5. See Figure 19.
3. Unlock Analyzer using security code.
4. Press Shift and while holding, press Setup. Release fingers from both keys.
49
MI 611-169 – July 2005
4. Configuration
5. Press Next several times until the code bL (Basic Setup Lock) is displayed (bL will be
the twentieth message displayed).
6. Press Enter, then use Next and ∆ until the personal security code is displayed (0800
from factory).
7. Press Enter.
8. When display returns to bL, press Next eight times until tEC1 is displayed.
9. Press Enter. The value 25.00 will be displayed.
10. Press Enter. When display returns to tEC1, press Next twice until tEC2 is displayed.
11. Press Enter. The value 25.00 will be displayed.
12. Press Enter. Disconnect 100 kΩ resistors from terminals 1 and 2 on TB2 and TB5.
13. Reconnect Sensor leads to terminals 1 and 2 of TB2 and TB5.
14. Lock Analyzer.
This completes the thermistor temperature electronics calibration.
Figure 19. Thermistor Temperature Simulation
(Plastic Enclosure Shown)
Changing the Analog Output
To change one or both of your analog outputs from a voltage to current output or vice versa,
jumpers must be moved and a recalibration performed. If changing from 4-20 mA to 0-20 mA or
vice versa, proceed to “Analog Output Calibration (LC01, HC01, LC02, HC02)” on page 53.
50
4. Configuration
MI 611-169 – July 2005
To Reposition Jumpers
1. Remove power to the unit.
2. On plastic General Purpose version: Remove optional rear cover. Remove the four
screws holding back panel in place.
On metal Field-Mounted version: Remove the four front corner screws holding the
display panel in place. Remove rear cover. Disconnect the green earth (ground) cable;
then feed wire from sensor and power connection through seals to allow free
movement of circuit boards.
! CAUTION
The four front screws are self-tapping and have a limited number of installation
cycles. Do not repeatedly remove and tighten these screws.
3. Slide circuit assembly out to access the upper circuit board designated AS700DX-03.
Plastic version slides out from the rear of its housing. Metal version slides out from the
front of its housing.
4. Refer to Figure 20 to identify jumper locations.
5. Use Table 13 to locate appropriate jumper positions.
Table 13. Jumper Positions for the Various Analog Outputs
Current
Voltage
Output
J5
J6
J7
J10
4-20 mA
or
0-20 mA
0-10 V dc
2-3
2-3
2-3
2-3
1-2
1-2
1-2
1-2
6. Move each jumper to its appropriate position.
7. Replace board assembly inside unit.
! CAUTION
On the plastic version, a string must be rigged through the loop in the ribbon cable
such that when the board assembly is slid into the housing, the string/ribbon cable
may be pulled back simultaneously, thus preventing damage to the cable. See
Table 20.
8. Replace cover. On metal enclosures, use Loctite (Part No. SO106ML) on the threads
of the front bezel screws, and Lubriplate (Part No. X0114AT) on threads of the rear
cover screws.
9. An analog output calibration will now be necessary. Refer to “Analog Output
Calibration (LC01, HC01, LC02, HC02)” on page 53.
10. Make appropriate changes to the analyzer identification label.
51
MI 611-169 – July 2005
4. Configuration
FDOA
RVOA
AS700FC-OA
Jumper Positions for the Various Analog Outputs
Current
Voltage
Output
J5
J6
J7
J10
4-20 mA
or
0-20 mA
0-10 V dc
2-3
2-3
2-3
2-3
1-2
1-2
1-2
1-2
Figure 20. Jumpers for Changing Analog Output
52
4. Configuration
MI 611-169 – July 2005
Analog Output Calibration (LC01, HC01, LC02, HC02)
This procedure is used to calibrate the analog outputs. This has been done at the factory and
should not require recalibration unless type of output has been changed. An ampmeter or
voltmeter is required. This procedure is used to change from 0 to 20 mA to 4 to 20 mA or vice
versa.
1. Connect an ammeter/voltmeter to the analog output terminals.
Metal Enclosure: For LCO1 and HCO1, connect to Channel 1 output terminal TB4.
For LC02 and HC02, connect to Channel 2 output terminals. See
Figure 21 and “Wiring of Metal Enclosure” on page 16.
Plastic Enclosure: For LC01 and HC01 connect to M+M- on TB3. For LC02 and
HC02 connect to M+M- of TB4. See “Wiring of Plastic Enclosure” on page 16.
2. Unlock the Analyzer using the security code.
3. Press Shift and while holding, press Setup. Release fingers from both keys.
4. Press Next several times until the code bL is displayed. Press Enter.
.
VOLT
OR AM
METER
-2 -2 -1 -1
TB4
TB2
TB5
TB1
TB3
Figure 21. Analog Output Calibration (Metal Enclosure Shown)
5. Use Next and ∆ until the personal security code is displayed (0800 from the factory).
Press Enter.
6. When display returns to bL, press Next until LC01 is displayed. Press Enter.
7. Calculate the low % input required by using the following formula:
Observed Reading – Desired Reading
% = ------------------------------------------------------------------------------------------ x 100
Analog High
53
MI 611-169 – July 2005
4. Configuration
Example:
(3.78
– 4.00mA)-----------------------------------------x 100 = – 1.1%
(20.00 mA)
8. Use Next and ∆ until the calculated value from Step 7 is displayed. Press Enter.
NOTE
1. Steps 7 and 8 may need to be repeated until observed value is equal to the desired
value.
2. To make a minus sign appear on the display, a digit other than zero must be
present on the display.
Example:
To make the display read –5.0%, first display 005.0% and then change the first digit to a
negative sign.
9. When the display returns to LC01, press Next once to display HC01. Press Enter.
10. Calculate the high % required using the following formula:
Observed Reading
% = -------------------------------------------- x 100
Desired Reading
Example:
10.42 V
------------------- x 100 = 104.2%
10.00
11. Use Next and ∆ until the calculated value from Step 10 is displayed. Press Enter. If
necessary, repeat Steps 10 and 11 until observed value is equal to the desired value.
12. Move ammeter to second set of output terminals. Repeat Steps 3 - 5. Then press Next
until LC02 is displayed. Press Enter.
13. Calculate the low % input required by using the following formula:
Observed Reading - Desired Reading
% = ------------------------------------------------------------------------------------------ x 100
Analog High
Example:
(3.78
– 4.00 mA)---------------------------------------x 100 = – 1.1%
20.00 mA
14. Use Next and ∆ until the calculated value from Step 13 is displayed. Press Enter.
NOTE
1. Steps 13 and 14 may need to be repeated until observed value is equal to desired
value.
2. To make a minus sign appear on the display, a digit other than zero must be
present on the display.
54
4. Configuration
MI 611-169 – July 2005
Example:
To make the display read –5.0%, first display 005.0% and then change the first digit to a
negative sign.
15. When the display returns to LC02, press Next once to display HC02. Press Enter.
16. Calculate the high % required using the following formula:
Reading- x 100
% = Observed
------------------------------------------Desired Reading
Example
10.42
V-----------------x 100 = 104.2%
10.00
17. Use Next and ∆ until the calculated value from Step 16 is displayed. Press Enter.
NOTE
Repeat Steps 16 and 17 until observed value is equal to the desired value.
18. Lock Analyzer using procedure in “Locking Analyzer Using Security Code” on
page 24.
This completes the Analog Output Calibration Procedure.
Using Sensor Diagnostics
There are nine basic setup parameters that deal with the three special sensor diagnostics found
with the 871DO/873DO system. These are listed in Table 15 in the order they appear in the
menu, along with the factory set code.
Table 16 illustrates the Probe Diagnostics Error Codes that are displayed locally alternating with
the measurement. Diagnostics for detection of membrane fouling (COAt), membrane breakage
(CAP), and loss of internal electrolyte (bubL) may be set independently.
When two DO Sensors are used and an error code has flagged, it may become necessary to
determine which sensor is producing the sensor error code. Press Shift and Temp simultaneously.
Table 14 explains the digit coding displayed.
Once an error has been flagged, the sensor must be serviced. Refer to Sensor Manual
MI 611-200, Section 4.1.
The error message disappears after the next diagnostic evaluation determines no sensor faults.
NOTE
Factory set values for FOt, CAt, bUt, dt, dOFF, don, and FdLL, as shown in
Table 15, should not be changed by the user without consultation with Invensys
Foxboro.
To utilize all of the sensor diagnostic features, the following criteria must be met:
♦
An Invensys Foxboro 871DO Dissolved Oxygen Sensor must be used.
♦ CELL Type Parameter (Ct) must be set to 4. (See “Changing CELL Type (Ct)” on
page 44.)
♦ Probe Diagnostic Enable (PdE) must be set to 0111.
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MI 611-169 – July 2005
4. Configuration
Sensor diagnostics are performed at intervals set by dt in minutes. During the diagnostics, the
display reads tESt (TEST), and the analog output values are held at their current value.
NOTE
The diagnostics overrides the measurement and any user interface while self-test is
functioning.
Three consecutive unacceptable diagnostic evaluations will flag a COAt error code. A single
erroneous diagnostic evaluation will flag the CAP or bubL code.
Table 14. Determining Which Sensor is Erroring
Digit
Displayed
Sensor Erroring
1
2
12
Sensor wired to CELL 1 channel
Sensor wired to CELL 2 channel
Both sensors contributing
Table 15. Setup Parameters
Parameter
PdE
dLc
FOt
CAt
bUt
dt
dOFF
don
FdLL
Description
Code
Probe Diagnostics Enable
Diagnostic Learning Control
Fouling Diagnostic Tolerance
Membrane Cap Diagnostic Tolerance
Bubble Diagnostic Tolerance
Diagnostic Interval Timing
Diagnostic OFF Window Timing
Diagnostic On Window Timing
Fouling Diagnostic Lower Limit
0000
0000
0050
0020
0020
0060
2.000
2.000
1.000
.
Table 16. Diagnostics Error Codes
Error Code
COAt
CAP
bubL
56
Cause
Membrane of the sensor has become coated and requires cleaning or servicing.
Electrolyte inside the sensor has changed concentration. The most likely cause
of this is membrane damage or another source of process ingress into the
electrolyte.
Excessive electrical resistance has formed between the auxiliary and test
electrodes. Possible sources include an air bubble forming inside the electrolyte
or excess AgCl has formed on the anode from normal usage.
4. Configuration
MI 611-169 – July 2005
Probe Diagnostics Enable (PdE)
This parameter allows the unique diagnostic features of the 871DO probe to be turned on or off.
This parameter is also used to disable the error code from flashing while servicing the probe.
Table 17 shows PdE configurations for using the Fouling, Membrane Breakage, and Electrolyte
diagnostics
Table 17. Probe Diagnostics Enable (PdE)
Digit 1
Fixed at 0;
Not Utilized
Digit 2
Digit 3
COAt diagnostics
0 - Diagnostics Off
1 - Diagnostics On
Digit 4
CAP diagnostics
0 - Diagnostics Off
1 - Diagnostics On
bubL diagnostics
0 - Diagnostics Off
1 - Diagnostics On
This 4-digit code is Factory set to 0000.
Diagnostic Learning Control (dLC)
This parameter is used to “teach the analyzer” what the particular sensor has as normal operating
characteristics. Table 18 shows dLC configurations of this parameter.
Table 18. Diagnostic Learn Modes
Digit 1
Fixed at 0;
Not Utilized
Digit 2
0 - Fixed Limits
1 - Learned Limits
Digit 3
0 - Learn Off
1 - Learn On
Digit 4
0 - Normal Operation
1 - Reset Learn Function
After calibration and startup, set PdE to 0111 and dLc to 0110. In this mode all diagnostics are
enabled and the Analyzer learns the normal operational characteristics of the probe being utilized.
It is necessary for the Analyzer to learn over several Diagnostic Timing Intervals (see “Diagnostic
Timing (dt)” on page 58). With dt set at 0060, a learn duration of 12 to 24 hours will therefore
provide 12 to 24 cycles of data. At the end of the learn duration, digit 3 is set back to 0 (dLc =
0100).
Fouling Diagnostic Tolerance (FOt)
The FOt parameter is set as a percentage. Setting this parameter creates an acceptable envelope of
values around the nominal value that will not trigger an error message. A tolerance of 0050%
creates an envelope of +/- 50% around the nominal value.
This 4-digit code is factory set to 0050.
Membrane Cap Diagnostic Tolerance (CAt)
The CAt parameter is set as a percentage. Setting this parameter creates an acceptable envelope of
values around the nominal value that will not trigger an error message. A tolerance of 0010%
creates an envelope of +/- 10% around the nominal value.
This 4-digit code is factory set to 0020.
57
MI 611-169 – July 2005
4. Configuration
Bubble Diagnostic Tolerance (bUt)
The bUt parameter is set as a percentage. Setting this parameter creates an acceptable envelope of
values around the nominal value that will not trigger an error message. A tolerance of 0010%
creates an envelope of +/- 10% around the nominal value.
This 4-digit code is factory set to 0020.
Diagnostic Timing (dt)
The dt parameter is set as a time in minutes. dt refers to the interval of time between the
diagnostic test cycle. All diagnostic tests are performed together either simultaneously or in rapid
sequence. When all three diagnostics are invoked, approximately 5 seconds pass. The dt interval
then restarts. The dt should not normally be set to less than 20 minutes.
This 4-digit code is factory set to 60 minutes.
Diagnostic Off Window Timing (dOFF)
The dOFF parameter is set as a time in seconds. dOFF defines a time interval that the unit must
wait after switching from the WORKING electrode to the TEST electrode before data collection
begins. The maximum dOFF time is 9.999 seconds.
This 4-digit code is factory set to 2 seconds.
Diagnostic On Window Timing (don)
The don parameter is set as a time in seconds. “don” defines a time interval that the unit collects
data for diagnostic purposes. The maximum don time is 9.999 seconds.
This 4-digit code is factory set to 2 seconds.
Fouling Diagnostic Lower Limit (FdLL)
The FdLL parameter is set as a current in microamps. FdLL defines the lower current value that
will be allowed when the COAt diagnosis is employed.
This 4-digit code is factory set to 1 µA.
Drive Voltage (dr)
The dr parameter is set as a voltage. It may be set within the range of +/- 1.50 volts. The applied
voltage required for the reduction of O2 is 700 mV.
This 4-digit code is factory set to +0.70 V.
NOTE
This parameter may be set to zero if a galvanic type probe is used, but should not
otherwise be altered.
58
5. Calibration
Calibration of a Sensor on the 873DO - General
Information
The 873DO Analyzer and sensor should be calibrated periodically to maintain optimum
measurement accuracy.
Calibration is also a good way to determine if a sensor is functioning properly.
Under no circumstances should a sensor be used on an analyzer for measurement or control
without a calibration being performed first. This includes new installations as well as after
servicing.
The user must make several decisions and entries before calibrating the sensor. These are typically
entered only once upon initial start-up of the system, and include:
Choice of Units: the analyzer can display units of ppm, percent saturation, or percent air.
Type of Zero Calibration: Cal Lo (typically at zero oxygen) can be set electronically within the
analyzer, or with the sensor in a zero oxygen environment.
Altitude: the elevation above sea level at which the unit will be operated must be entered into the
873DO prior to sensor calibration.
Solution or Air Calibration: the method in which the sensor will be calibrated must also be entered
into the 873DO prior to sensor calibration. The sensor may be calibrated suspended in the air or
in a solution. A grab sample calibration with laboratory analysis or calibrated portable analyzer
will be required to determine the dissolved oxygen concentration in order to calibrate a
functioning sensor in the process solution.
In addition to measurement calibration, a procedure must be implemented to correct temperature
measurements that differ from actual values (such as when sensor cable length and/or connections
may add resistance to the reported values; see “Temperature CELL Factor (tCF1, tCF2)” on
page 61). This is extremely important for temperature correction to be applied to the measurement
correctly.
The preceding measurement parameters should be implemented prior to the sensor calibration. In
addition, the following guidelines should be observed:
♦
Sensors should be thoroughly cleaned before calibration.
♦
Sufficient time for sensor and thermo-compensator thermal equilibrium must be
allowed. The temperature should display the correct temperature of the medium in
which it is placed. The sensor should be kept out of direct sunlight during an air
calibration.
♦
The correct ppm value should be used during solution calibrations. Pressure and
temperature affect the oxygen concentration. Use reliable methods and equipment to
determine oxygen values before calibrating the process sensor.
♦
Sufficient time for steady state of the sensor membrane (polarization) must be allowed
when doing a calibration.
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5. Calibration
! CAUTION
On metal units, do not remove four front panel screws and remove electronics
package for calibration. The self-tapping screws have a limited number of installation
cycles and will not function properly with repeated use.
Three different sensor calibration procedures are given in this manual. “Air Calibration with
Electronic Zero” on page 62 is easily implemented when the sensor is removed from the process,
such as after maintenance. This technique offers the advantage of simplicity. Additional standard
solutions, gases, or equipment are not required. This is a single point calibration with an
electronic instrument zero providing the low calibration point and water saturated air providing
the Cal Hi (span). “Solution Calibration with Electronic Zero” on page 64 is also a single point
calibration procedure. The advantage of this method is the sensor remains installed in the process.
An electronic instrument zero provides the zero calibration point, and the span is set by changing
the display to agree with the dissolved oxygen value obtained by another method. “Solution
Calibration with Solution Zero” on page 65 is the most rigorous calibration technique. The
method may be used to check electrode function at two known dissolved oxygen levels. A sample
devoid of oxygen is used to set (or check) the Cal Lo value (zero). A second solution with known
dissolved oxygen concentration is required to span the analyzer (Cal Hi). The technique can be
used after performing sensor maintenance as the sensor must be removed from the process.
Startup Setup Parameters
Units, Zero, Altitude, and Calibration Type Setup
1. Unlock analyzer (see“Unlocking Analyzer Using Security Code” on page 24).
2. Press Shift and while holding, press Setup. Release fingers from both keys.
3. Press Next several times until the code bL (Basic Setup Lock) is displayed.
4. Press Enter, and then use Next and ∆ until personal security code is displayed (0800
from factory).
5. Press Enter.
6. When display returns to bL, press Next two times until the entry FSC is displayed.
7. Press Enter, then use Next and ∆ until the desired unit of measurement is displayed.
See “The Full Scale Range (FSC)” on page 45.
8. Press Enter.
9. When display returns to FSC, press Next once. The code SErO will be displayed. See
“Setting Active or Electronic Zero (SErO)” on page 46.
10. Press Enter, then use ∆ to make display read the desired code.
11. Press Enter.
12. When display returns to SErO, press Next once. The code Alt will be displayed. See
“Setting Altitude” on page 46.
13. Press Enter, then use ∆ and Next to make display read the Altitude (in feet above sea
level) at which the sensor will be operated.
60
5. Calibration
MI 611-169 – July 2005
14. Press Enter.
15. Allow unit to time out. Er 4 should be flashing.
16. For ppm FSC only: Determine if a solution or air calibration will be used. Press Shift
and while holding, press Setup. Release fingers from both keys. Press Next until Cd is
displayed. Press Enter, then use ∆ to make display read the desired code. 0000 is used
for an air calibration. 0001 or 0002 is used for a solution calibration.
17. Wire sensor(s) to analyzer. See “Wiring of Plastic Enclosure” on page 16 or “Wiring
of Metal Enclosure” on page 16.
18. When using two sensors, configure pertinent parameters to appropriate values. See
“User Notes” on page 77 and “Configuration” on page 23 for additional setup
information.
Temperature CELL Factor (tCF1, tCF2)
An accurate temperature signal is required for proper temperature compensation. The
temperature CELL factors (tCF1 and tCF2) are used to offset a small deviation from ideality due
to cable resistance. The procedures found in “Determining tCF” on page 61 and “Entering a tCF
Value” on page 62 are recommended to correct for these offsets. A 100 kΩ thermistor circuit is
used for automatic temperature compensation on the 873DO Analyzer.
Determining tCF
1. Place the Dissolved Oxygen sensor and an accurate Centigrade thermometer (with
.1 C resolution) into a container of liquid. The CELL code should reflect the sensor
being used. See “CELL Display and Output Configuration (CELL)” on page 26.
Allow the sensor to reach thermal equilibrium.
2. Press Temp. Put the analyzer into Automatic Temperature Compensation, no decimal
after the C. If there is a decimal after the “C”, it should be removed. Press ∆ once after
pressing Temp; then press Enter.
3. Read the temperature displayed on the 873 to the hundredths place. When Temp is
pressed, the present temperature value with tenths place will alternate with the “C”
legend. The value read by the 873 must now be viewed to the hundredths place. Press
Temp followed by Next five times. Only three numbers may be viewed on the display,
and the first digit will not be visible (e.g., 25.20 will be displayed as 5.20).
4. Determine the difference in values between the two temperature devices (e.g., the
thermometer reads 24.70°C, and the 873 says (2) 5.20C; the 873 is reading higher by
.50C).
5. Subtract this value from 25.00 (e.g., 25.00 –.50 = 24.50). This is the TCF value to be
entered.
NOTE
If the 873 value is less than the thermometer, the difference should be added to
25.00.
6. This procedure should be repeated with the second sensor, if used. See CELL code
(“CELL Display and Output Configuration (CELL)” on page 26).
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5. Calibration
Entering a tCF Value
1. Unlock Analyzer (see“Unlocking Analyzer Using Security Code” on page 24).
2. Press Shift and while holding, press Setup. Release fingers from both keys.
3. Press Next several times until the code bL (Basic Setup Lock) is displayed.
4. Press Enter, and then use Next and ∆ until personal security code is displayed (0800
from factory).
5. Press Enter.
6. When display returns to bL, press Next several times until the entry tCF1 or tCF2
(depending upon the sensor you wish to calibrate) is displayed.
7. Press Enter and then use Next and ∆ until desired value (see “Determining tCF” on
page 61) is displayed.
8. Press Enter.
9. Recheck any differences that exist between a thermometer and temperature displayed
on the 873.
10. Lock Analyzer using procedure in “Locking Analyzer Using Security Code” on
page 24.
Air Calibration with Electronic Zero
NOTE
The following start-up parameters must be set first (see “Startup Setup Parameters”
on page 60).
(If FSC = 100 ppm)
FSC
SEr0
Cd
→
→
→
ALt
tCF
100%, 25% →
0001
0000
100 ppm, 100
1. Unlock Analyzer if locked (see “Unlocking Analyzer Using Security Code” on
page 24).
2. Remove the DO sensor from the process. Clean and inspect the sensor. Provide
maintenance if required (consult sensor instructions).
3. Wait until the sensor has reached thermal equilibrium with the air.
4. Check and adjust the CELL code of the unit. Refer to “CELL Display and Output
Configuration (CELL)” on page 26. The code should be 1XXX if sensor 1 is being
calibrated, and 2XXX if sensor 2 is being calibrated.
5. Check and adjust the Cd code of the unit. Refer to “Compensation and Damping
(Cd)” on page 28. Set this code to read “0000”.
6. Press Shift and while holding, press Cal Lo. Release fingers from both keys. The
display will say 000.0%. Press Shift for a full ten seconds to freeze display at 000.0%
and allow electronics to stabilize fully. Release finger from Shift . Press Enter. (Press
Enter only once.)
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5. Calibration
MI 611-169 – July 2005
7. Suspend sensor in the air a few inches above water to ensure water vapor saturation.
The sensor should be free from direct sunlight or vibration. Wait several minutes after
the zero calibration to ensure that the sensor has reestablished equilibrium before
proceeding.
NOTE
If the air is not saturated with water vapor, the calibration may be in error, yielding
lower concentrations in solution than are actually present.
8. Press Shift and while holding, press Cal Hi. Release fingers from both keys.
9. If FSC is 100%, 25%, or 100 (no units), the value entered at the time of the previous
calibration will be displayed. Use Next and ∆ until display reads the correct value.
Press Enter.
If FSC is 100 ppm, the value 100% will be displayed, and cannot be altered. Press
Enter.
NOTE
ppm FSC; when calibration is complete the unit will automatically default to the
ppm equivalent with fresh water temperature compensation for the altitude entered
and temperature measured. See Table 19 on page 66 for value expected at sea level at
760 torr. If salt water compensation is required, the Cd code will require
adjustment. See “Compensation and Damping (Cd)” on page 28.
10. Repeat Steps 2 through 9 on second sensor.
11. Set display damping if desired. Check and adjust the Cd code of the unit. Refer to
“Compensation and Damping (Cd)” on page 28.
12. Lock Analyzer (see “Locking Analyzer Using Security Code” on page 24).
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5. Calibration
Solution Calibration with Electronic Zero
NOTE
The following start-up parameters must be set first (see “Startup Setup Parameters”
on page 60):
(If FSC = 100 ppm)
FSC
100%, 25% →
100 ppm, 100
SEr0
0001
Cd
000X
→
ALt
→
tCF
→
0001
0002
1. Unlock Analyzer if locked (see “Unlocking Analyzer Using Security Code” on
page 24).
2. Analyze oxygen concentration using a grab sample with laboratory analysis or portable
analyzer and sensor used directly in the process.
3. Ensure that the sample and process are at the same temperature and altitude. The
portable analyzer should be calibrated correctly and located as close to the process
sensor as possible.
4. Check and adjust the CELL code of the unit. Refer to “CELL Display and Output
Configuration (CELL)” on page 26. The code should be 1XXX if sensor 1 is being
calibrated, and 2XXX if sensor 2 is being calibrated.
5. Check and adjust the Cd code of the unit. “Compensation and Damping (Cd)” on
page 28. Set this code to read 000X if the FSC is 100%, 25%, or 100 (no units). Set
this code to 0001 or 0002 (fresh or salt water temperature compensation) if FSC is
100 ppm.
6. Press Shift and while holding, press Cal Lo. Release fingers from both keys. The
display will say 000.0 (with appropriate units displayed). Press Shift for a full ten
seconds to freeze display at 000.0 and allow electronics to stabilize. Release finger from
Shift . Press Enter. Wait several minutes after the zero calibration to ensure that the
sensor has reestablished equilibrium before continuing.
7. Press Shift and while holding, press Cal Hi. Release fingers from both keys.
8. The value entered at the time of the previous calibration will be displayed. Use the
Next and ∆ until display reads the concentration of oxygen determined by the
alternate analysis. Press Enter.
9. Repeat Steps 2 through 9 on second sensor if connected.
10. Set display damping if desired. Check and adjust the Cd code of the unit. Refer to
“Compensation and Damping (Cd)” on page 28.
11. Lock Analyzer (see “Locking Analyzer Using Security Code” on page 24).
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5. Calibration
MI 611-169 – July 2005
Solution Calibration with Solution Zero
NOTE
The following start-up parameters must be set first (see “Startup Setup Parameters”
on page 60):
(If FSC = 100 ppm)
FSC
100%, 25% →
100 ppm, 100
SEr0
0000
→
ALt
→
tCF
→
Cd
000X
0001
0002
1. Unlock Analyzer if locked (see “Unlocking Analyzer Using Security Code” on
page 24).
2. Remove the DO sensor from the process. Clean and inspect the sensor. Provide
maintenance if required (consult sensor instructions).
3. Check and adjust the CELL code of the unit. Refer to “CELL Display and Output
Configuration (CELL)” on page 26. The code should be 1XXX if sensor 1 is being
calibrated, and 2XXX if sensor 2 is being calibrated.
4. Check and adjust the Cd code of the unit. Refer to “Compensation and Damping
(Cd)” on page 28. Set this code to read 000X if the FSC is 100%, 25%, or 100 (no
units). Set this code to 0001 or 0002 (fresh or salt water temperature compensation) if
FSC is 100 ppm.
5. Freshly prepare a small quantity of 5% sodium sulfite solution in a small bottle that is
sealable (2.5 g sodium sulfite/50 ml deionized water). The sodium sulfite will
consume the oxygen in the water, providing an oxygen-free environment in which to
zero the sensor. Keep the bottle sealed until ready to use. Do not reuse the solution or
store longer than one week.
6. Place the 871DO sensor into the solution with the membrane side down. Angle
sensor to rest on the edge of the membrane cap, not on the permeable membrane
surface. Do not damage the membrane. Allow the sensor to sit undisturbed in the
oxygen-free solution for at least 10 minutes.
7. Press Shift and while holding, press Cal Lo. The display will show the last value
entered into this parameter. Release fingers from both keys. Using Next and ∆ make
the display read 000.0 (with appropriate units displayed). Press Enter.
8. Remove sensor from the sodium sulfite solution and rinse.
9. Place sensor in second solution with known oxygen concentration. This may be the
process sample which was analyzed by a portable analyzer (as close to the process
sensor as possible), a laboratory analysis of a grab sample, or a “standard”, a water
sample with known concentration of oxygen. The volume of the sample should be
generous and stirred, for oxygen is consumed during the determination. Allow the
sensor to sit at least 10 minutes and proceed only after stable readings are noted.
10. Press Shift and while holding, press Cal Hi. Release fingers from both keys.
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5. Calibration
11. The value entered at the time of the previous calibration will be displayed. Use Next
and ∆ until display reads the concentration of oxygen determined by the alternate
analysis method. Press Enter.
12. Repeat Steps 2 through 11 on second sensor, if connected.
13. Set display damping if desired. Check and adjust the Cd code of the unit.
14. Lock Analyzer (see “Locking Analyzer Using Security Code” on page 24).
Oxygen Solubility Tables
This table illustrates the relationship between the solubility of oxygen in air-saturated fresh water
at 760 torr (1 ATM) as a function of temperature. Changes in altitude and salt concentration will
affect these values.
Table 19. Oxygen Solubility Tables
Temp
°C
0
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
66
Temp
°F
32.0
33.8
35.6
37.4
39.2
41.0
42.8
44.6
46.4
48.2
50.0
51.8
53.6
55.4
57.2
59.0
60.8
62.6
64.4
66.2
68.0
69.8
71.6
73.4
75.2
77.0
Fresh Water
(ppm)
14.6
14.2
13.8
13.4
13.1
12.7
12.4
12.1
11.8
11.5
11.3
11.0
10.7
10.5
10.3
10.1
9.8
9.6
9.4
9.2
9.1
8.9
8.7
8.6
8.4
8.2
Temp
°C
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
Temp
°F
78.8
80.6
82.4
84.2
86.0
87.8
89.6
91.4
93.2
95.0
96.8
98.6
100.4
100.4
104.0
105.8
107.6
109.4
111.2
113.0
114.8
116.6
118.4
120.2
122.0
Fresh Water
(ppm)
8.2
8.0
7.8
7.7
7.6
7.4
7.4
7.2
7.1
7.0
6.9
6.8
6.7
6.6
6.5
6.4
6.3
6.2
6.1
6.0
5.9
5.8
5.7
5.6
5.5
6. Diagnostics
Using the 873DO Analyzer to Troubleshoot a Sensor
or Analyzer Problem
Table 20. Error Codes
873 Error
Code
Description
Remedy
Er 1
Instrument Fault
Er 2
Temperature Error; the temperature
sensor used on the 873 is a 100 k Ω
thermistor. At temperatures around
25°C (77°F), it should read
100 k Ω. The sensor or 873 Analyzer
may be at fault.
Er 4
Er 4 flashes when the 873 Analyzer is
not calibrated after changing the Ct
code or FSC.
Sensor membrane has become coated Clean sensor.
with a film.
Replace membrane.
Reset PdE; relearn dLC (see page 57).
Sensor membrane has become
Replace membrane.
damaged. Process ingress into
Examine membrane, replace if necessary.
electrolyte reservoir.
Replace electrolyte.
Reset PdE; relearn dLC (see page 57).
Loss of electrolyte.
Examine membrane, replace if necessary.
Excess AgCl buildup on auxiliary
Replace electrolyte.
electrode.
Replace sensor.
Reset PdE; relearn dLC (see page 57).
COAt
CAP
bubL
Enter LCC twice to restart the analyzer.
Disconnect sensor and re-power analyzer.
Try sensor on another unit or other channel.
Verify that instrument is functioning properly.
(1) Check temperature on both channels in
automatic temperature compensation mode (See
“Temp Key” on page 22). Compare to range set
in UtL and LtL. Adjust range if necessary.
(2) Substitute resistors across terminals 1 and 2 of
TB2 and TB5 (see Table 21) or measure the
resistance between wires 1 and 2 of sensor (brown
and clear). If the resistance between 1 and 2 of the
sensor is reading a value which deviates greatly
from correct resistance, it is not functioning
properly and should be replaced. For the short
term, if the process measurement does not change
temperature, or if the process has very wide
accuracy specifications, manual temperature
operation may be chosen.
Calibration with sensor is necessary. Both channels
must be calibrated. See “Calibration” on page 59.
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6. Diagnostics
Additional Troubleshooting
Temperature measurement inaccuracies may also occur with the 873DO or 871DO Sensor that
may be undetectable using the 873DO Analyzer alone. Table 21 will help troubleshoot these
problems. Note, however, when precision resistors are employed, tCF values must be set to 25.00
for accurate temperature display.
Table 21. Temperature vs. Resistance Values
C
F
100KΩ Thermistor
Resistance
–5
0
10
20
25
30
40
50
60
70
80
90
100
105
110
120
130
150
23
32
50
68
77
86
104
122
140
158
176
194
212
221
230
248
266
302
461.550 kΩ
351.020 kΩ
207.850 kΩ
126.740 kΩ
100.000 kΩ
79.422 kΩ
51.048 kΩ
33.591 kΩ
22.590 kΩ
15.502 kΩ
10.837 kΩ
7.7077 kΩ
5.5693 kΩ
4.7604 kΩ
4.0829 kΩ
3.0334 kΩ
2.2811 kΩ
1.3319 kΩ
NOTE
1. Resistance checks of sensor leads should be taken between Wires 1 and 2 (brown
and clear).
2. Resistor substitution of Sensor Leads 1 and 2 should be made to Terminals 1 and
2 of strips TB2 and TB5 on the 873DO Analyzer.
Table 22 has additional troubleshooting symptoms and remedies that are undetectable using the
873DO Analyzer alone.
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6. Diagnostics
MI 611-169 – July 2005
Table 22. Troubleshooting Symptoms
Problem
Cause
Display LEDs not Wiring/Power Connection
functioning
Analyzer Defective
Sensor/873DO
Defective sensor
cannot be
calibrated
Reading sensitive Recent membrane cap
to sensor motion replacement
Temperature
reading is
incorrect
Slow response
Reading extremely
high
Dual sensors
calibrate OK in air
but are erratic in
process
Noisy signal
Accuracy
Reading extremely
high. Current
(µA) elevated also.
Remedy
-Verify that line power and wiring are correct.
-Replace.
-Replace electrolyte.
-Replace membrane cap.
-Replace sensor.
-Verify patch cable OK.
-Allow more time before calibrating sensor. Wire
sensor to 873 power analyzer, and allow time for
sensor to polarize.
-Replace membrane cap.
Insufficient membrane
tension
Calibration incorrect
-Adjust tCF1 or tCF2.
Thermistor or wire broken -Check sensor leads 1 and 2 vs. values in Table 21.
-Also, see Er 2 in Table 20.
Electrolyte depleted
-Replace electrolyte in sensor.
Membrane coated or
-Replace electrolyte and membrane cap.
Insufficient membrane
tension
Sensor inoperative
-Replace sensor.
Damaged membrane
-Replace electrolyte and membrane cap.
Ground loop
-See below.
Ground loop
-Check membrane for leakage. Replace cap.
-Check for electrolyte leakage above cap. Replace
O-ring.
-Check electrolyte vent for leakage. Reseal vent cap.
May be flow related
-Check Analyzer noise by simulating sensor signal
with a resistor (See “Electronic Test for Verification
of Operation of the 873DO Analyzer” on page 70).
-Increase damping.
-Reorient sensor.
-ECS cleaner not adjusted correctly.
-Solution extremely turbulent. Reorient sensor and
place in weir.
Insufficient membrane
-Replace membrane cap.
tension
Sensor membrane coated -Accuracy of sensor may be affected by coating or
films. Consult sensor MI for cleaning
recommendations.
Application problem
-Replace electrolyte and membrane cap.
Older style analyzer
-Verify analyzer is Style CE.
Older style sensor
-Verify Style B; 871DO - C Style B sensor.
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MI 611-169 – July 2005
6. Diagnostics
Electronic Test for Verification of Operation of the
873DO Analyzer
The following procedure is included to aid in troubleshooting an installation. The procedure
verifies cable and analyzer integrity. It should not be used to calibrate a sensor or analyzer, but
only to eliminate the cable and analyzer as contributors to a troublesome installation.
Test with the CELL Simulator (Part No. BS806KM)
When cables with quick disconnect connectors are in use, use CELL Simulator (Part
No. BS806KM) and the procedure below.
1. Disconnect the sensor from the patch cord.
2. Place the Analyzer into manual temperature compensation with the display reading
25.0C. or 77.0F. A decimal must be present after the C or F. See “Temp Key” on
page 22.
3. Press Shift and while holding, press µA. The display should read 0.0 ±.5 µA.
4. Connect the CELL simulator to the patch cord.
5. Place the Analyzer into the automatic temperature compensation mode. No decimal
should be present after the measurement unit. See “Temp Key” on page 22. Press
Temp. Depending upon the tCF value that is input into the Analyzer, the temperature
should read close to 25C or 77F. If tCF has been adjusted for long cable lengths, the
temperature value displayed may vary. The value displayed should be stable. Allow
unit to time out.
6. Press Shift and while holding, press µA. The display should read 18.7 ±.5 µA.
7. If the Analyzer passes this test, the sensor would be suspect in the installation.
This procedure should be repeated with the second sensor cable, if used. Adjust CELL code to
alternate sensor. See “CELL Display and Output Configuration (CELL)” on page 26.
Test with Resistors
When sensors are connected directly to the analyzer, a junction box is employed, or the cable and
analyzer did not pass the procedure above, the procedure below should be used.
Five resistors are required: 100 kΩ, 300 Ω, 35 kΩ, 0 Ω (short), and one resistor between 35 k and
175 kΩ . Use Figure 22 as a connection guide throughout the following steps.
NOTE
To perform the following test on CELL 1, the first digit in the CELL parameter
must be 1 (i.e., 1XXX).
To perform the test on CELL 2, the first digit in the CELL parameter must be 2
(i.e., 2XXX).
1. Disconnect the sensor or the patch cord from the Analyzer.
2. Place the Analyzer into manual temperature mode with the display reading 25.0 C. or
77.0 F. A decimal must be present after the C or F. See “Temp Key” on page 22.
70
6. Diagnostics
MI 611-169 – July 2005
3. Place the following resistors on the terminal board:
a. Place 300 Ω between 3 and 3A.
b. Place 35 kΩ between 3A and 6.
c. Place a short (0 Ω) between 5 and 6.
4. Record the value of PdE.
5. Set PdE to 0111.
6. Record the value of dt.
7. Set dt to 0002.
8. Record the value of dLc.
9. Set dLc to 0111.
10. Press Enter.
11. Set dLc to 0110.
12. Set dt to 0001.
13. Wait for three to five test cycles to pass.
14. Set dt to 0002.
15. Set dLc to 0100.
bubL Diagnostics
16. Remove the short between 5 and 6.
a. Wait for one test cycle to pass.
b. Look for error code bubL.
17. Replace the short between 5 and 6.
a. Wait for one test cycle to pass.
b. The error code should disappear.
CAP Diagnostics
18. Remove the 300 Ω resistor between 3 and 3A.
a. Wait for one test cycle to pass.
b. Look for error code CAP.
19. Replace the 300 Ω resistor between 3 and 3A.
a. Wait for one test cycle to pass.
b. The error code should disappear.
COAt Diagnostics
20. Set PdE to 0101.
21. Remove the 300 Ω resistor between 3 and 3A.
71
MI 611-169 – July 2005
6. Diagnostics
22. Place a short between 3 and 5.
a. Wait for four test cycles to pass.
b. Look for error code COAt.
23. Remove the short between 3 and 5.
a. Wait for one test cycle to pass.
b. The error code should disappear.
Current Diagnostics
24. Set PdE to 0000.
25. Remove the 35 kΩ resistor between 3A and 6.
26. Install a resistor between 3A and 6 with a resistance in the range of 35 k to 175 kΩ ..
Press shift <µA>. Display should read: 0.7/(resistance) = µA +/- 0.5 µA.
a. .Calculate the current value that should be present by using the formula:
.700
------------------------------------------------------- x 1000 = µA
Resistor Value (in kΩ )
Examples:
.7-----x 1000 = 20 µA
35
.7
---------x 1000 = 4 µA
175
b. Press Shift and while holding, press µA. The display should read the calculated
value ±.5 µA.
Temperature Diagnostics
27. Install 100kΩ between 1 and 2.
28. Place the Analyzer into the automatic temperature mode. See “Temp Key” on page 22.
29. Press Temp. With a 100 kΩ resistor, the display should read approximately 25 C or
77 F.
30. Remove all resistors and shorts.
31. Re-enter the values recorded for PdE, dt, and dLc.
32. If the Analyzer passes these tests, the sensor (or cable) would be suspect in the
problem installation.
33. This procedure should be repeated with the second sensor CELL channel, if used.
Adjust CELL code to alternate sensor. See “CELL Display and Output Configuration
(CELL)” on page 26.
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6. Diagnostics
MI 611-169 – July 2005
35KΩ
JUMPER
TO
100KΩ 300Ω 175KΩ WIRE
1
2
3 3A 4
1
5 6
7
35KΩ
TB2
2
3 3A 4 5
TB4
6
7
TB5
TB1
TB3
Figure 22. Test Resistors
Error Codes
When the Analyzer is operating normally, the measurement value is displayed constantly. If error
or alarm conditions exist, the display alternates between the measurement value and the
error/alarm message at a one second rate. The alternate (error/alarm) messages are shown in
Table 23.
.
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MI 611-169 – July 2005
6. Diagnostics
Table 23. Error/Alarm Messages
Alternate
Display
Er 1
Er 2
Er 3
Er 4
AL 1
AL 2
A1A2
••••
Err
COAt
CAP
bubL
Condition
Priority
Action Required to Clear Error
Message
Instrument fault, RAM/ROM,
software watchdog timer
1
1. Reenter LCC using procedure on
(Highest)
page 49.
2. Power down unit. Then reapply
power.
3. On plastic unit, verify that metal
shorting strip used in shipping has
been removed from terminal block.
User-defined temperature range
6
1. Change user-defined temperature
error or temperature measurement
limits, UtL or LtL.
error
2. Replace sensor.
3. Place temperature in manual mode
(e.g., 25.C.).
4. See “Using the 873DO Analyzer to
Troubleshoot a Sensor or Analyzer
Problem” on page 67.
User-defined measurement range
7
1. Change user-defined measurement
error
limits, UL or LL.
2. Replace sensor.
3. Ground loop (see Table 22).
Measurement calibration incorrect
2
Recalibrate sensors on both channels.
Alarm 1 condition triggered
9
Alarm 2 condition triggered
9
Both alarms are triggered
8
simultaneously
Measurement over or under range
10
of analog output limits
Incorrect code or parameter
2
Check code and reenter.
attempted
Membrane fouled
4
1. Clean sensor.
2. Replace membrane.
Broken membrane; process ingress
3
Replace membrane cap and electrolyte.
into electrolyte
AgCl coating on auxiliary electrode
5
Replace sensor.
Air bubble in electrolyte
Refill electrolyte.
Low electrolyte
NOTE
If two or more errors exist simultaneously, the Analyzer flashes only the error with
highest priority. If the highest priority error is cleared and a lower priority error still
remains, the Analyzer then flashes the highest priority error of the remaining errors.
74
6. Diagnostics
MI 611-169 – July 2005
Detachable Configuration Field Sheet
Configuration Setup Entries
Symbol
CELL
Hold
Cd
AC1
Att1
AFt1
AdL1
AC2
Att2
AFt2
AdL2
UL
LL
UtL
LtL
HO1
LO1
HO2
LO2
Parameters and Values Accessed
Configuration of Display, Analog Outputs
Hold and sets the Analog output value in Hold
Compensation and Damping
–Damping Factor
–Temperature Compensation
Alarm 1 Control
–Measurement Selection
–Low/High/Instrument plus Passive/Active State
–% Hysteresis
Alarm 1 Trigger Timer
Alarm 1 Feed Time
Alarm 1 Delay Time
Alarm 2 Control
–Measurement Selection
–Low/High/Instrument plus Passive/Active State
–% Hysteresis
Alarm 2 Trigger Timer
Alarm 2 Feed Time
Alarm 2 Delay Time
User-Defined Upper Measurement Limit - Both CELLs
User-Defined Lower Measurement Limit - Both CELLs
User-Defined Upper Temperature Limit - Both CELLs
User-Defined Lower Temperature Limit - Both CELLs
100% Analog Output - Channel 1
0% Analog Output - Channel 1
100% Analog Output - Channel 2
0% Analog Output - Channel 2
User Settings
Basic Setup Entry Selection
Symbol
bL
Ct
FSC
SEr0
ALt
PC
LCC
tCF1
tEC1
tCF2
tEC2
LC01
HC01
LC02
HC02
PdE
dLC
FOt
CAt
bUt
dt
dOFF
don
FdLL
dr
Parameter and Value Accessed
User Settings
Basic Setup Lock Control
Sensor CELL Type
Full Scale Value
Zero Calibration
Altitude Calibration
Probe Calibration
Lock Change Code
Temperature CELL Factor CELL 1
Temperature Electronics Calibration CELL 1
Temperature CELL Factor CELL 2
Temperature Electronics Calibration CELL 2
Low Calibration Analog Output 1
High Calibration Analog Output 1
Low Calibration Analog Output 2
High Calibration Analog Output 2
Probe Diagnostic Enable
Diagnostic Learning Control
Fouling Diagnostic Tolerance
Membrane Cap Diagnostic Tolerance
Bubble Diagnostic Tolerance
Diagnostic Interval Timing
Diagnostic Off Window Timing
Diagnostic On Window Timing
Fouling Diagnostic Lower Limit
Drive Voltage Setting
75
MI 611-169 – July 2005
Digit 1
DISPLAY
1-CELL 1
2-CELL 2
7-Ratio
9-Difference
6. Diagnostics
CELL Code - Display and Output Configuration
Digit 3
OUTPUT 1
0-Interrogate both channels
1-Dissolved Oxygen CELL 1
1-Ignore non- configured
2-Dissolved Oxygen CELL 2
channel
3-Temp CELL 1
4-Temp CELL 2
7-Ratio
9-Difference
Digit 2
Digit 1
0 – No Hold
Hold ON, Analog Output on Hold
1 – Alarms held in present state
2 – Alarms held in off state
3 – Alarms held in on state
Digit 1
Damping
0 = none
1 = 10 seconds
2 = 20 seconds
3 = 40 seconds
Digits 1 and 2
00 to 99 minutes
HOLD Code - Hold Analog Output Values
Digits 2, 3, and 4
000 to 100% of Analog Output Range
Cd Code - Compensation and Damping
Digits 3 and 4
ppm Temperature Compensation
00=% Saturation
01=Pure Water
02=Saltwater
Digit 2
0
Digit 1
MEAS. SELECTION
1 – Diss. Oxygen CELL 1
2 – Diss. Oxygen CELL 2
3 – Temp CELL 1
4 – Temp CELL 2
7 – % Ratio
9 – Difference
Digit 4
OUTPUT 2
1-Dissolved Oxygen CELL 1
2-Dissolved Oxygen CELL 2
3-Temp CELL 1
4-Temp CELL 2
7-Ratio
9-Difference
AC1 and AC2 Codes - Alarm Control
Digit 2
CONFIGURATION
1 – Low/Passive
2 – Low/Active
3 – High/Passive
4 – High/Active
5 – Instrument/Passive
6 – Instrument/Active
7 – Hold/Passive
8 – Hold/Active
Digits 3 & 4
HYSTERESIS
00 to 99% of Full Scale
0.0 to 9.9% (% mode)
AFt1, AdL1, AFt2, AdL2, Att1 and Att2 Time Codes
Digit 3
Digit 4
0 to 9 tenths of minutes
0 to 9 hundredths of minutes
Error/Alarm Messages
Alternate Display
Condition
Er 1
Instrument fault, RAM/ROM, software watchdog timer
Er 2
User-defined temperature range error or temperature
measurement error
Er 3
User-defined measurement range error
Er 4
AL 1
AL 2
A1A2
²²²²
Err
COAt
CAP
bubL
Measurement calibration incorrect
Alarm 1 condition triggered
Alarm 2 condition triggered
Both alarms are triggered simultaneously
Measurement over or under range of analog output limits
Incorrect code or parameter attempted
Membrane fouled
Priority
Action Required to Clear Error Message
1
1. Reenter LCC using procedure onpage 49.
(Highest) 2. Power down unit. Then reapply power.
3. On plastic unit, verify that metal shorting strip used
in shipping has been removed from terminal blocks.
6
1. Change user-defined temperature limits, UtL or LtL.
2. Replace sensor.
3. Place temperature in manual mode (e.g., 25.C.).
4. See Section 6.
7
1. Change user-defined measurement limits, UL or LL.
2. Replace sensor.
3. Ground loop (see Table 22).
2
1. Recalibrate sensors on both channels.
9
9
8
10
2
Check code and reenter.
4
1. Clean sensor.
2. Replace membrane.
3
Replace membrane cap and electrolyte.
5
Replace sensor.
Refill electrolyte.
Broken membrane; process ingress into electrolyte
AgCl coating on auxiliary electrode
Air bubble in electrolyte
Low electrolyte
NOTE: If two or more errors exist simultaneously, the Analyzer flashes only the error with highest priority. If the highest priority error is cleared and a
lower priority error still remains, the Analyzer then flashes the highest priority error of the remaining errors.
76
7. User Notes
Single Sensor Use
This section allows fault-free setup of the 873DO for single sensor use. Because two sensor inputs
are available on the 873 Analyzer, proper configuration is required to prevent errors from flagging.
After wiring the sensor, follow the steps below to determine the pertinent configuration code
assignments. Error codes will occur if the unit is configured improperly.
CELL 1 Configuration
1. Wire Sensor to TB2 (see Figure 10 or Figure 11);
CELL 1 terminals 1, 2, 3, 3A, 4, 5, 6.
2. Choose CELL Code.
Digit
1
2
3
4
1
1
1
or
3
1
or
3
3. Will you be using Analog output(s)?
If Yes, set to desired values.
If No, set to values below.
See Section:
H01 on page 42
H01 = 999.9
L01 on page 42
L01
= -9.9
4. Will you be using Alarms?
AC1
AC2
Digit
Digit
1
2
3
4
1
2
3
4
1
or
3
X
X
X
X
X
X
X
X
X
1
or
3
X
X
X
If Yes, set digits 2, 3, and 4 as desired.
If No, set AC1 = 1300
set AC2 = 1100
set Alm1= 999.9
set Alm2= –9.9
77
MI 611-169 – July 2005
7. User Notes
CELL 2 Configuration
1. Wire Sensor to TB5 (see Figure 10 or Figure 11);
CELL terminals 1, 2, 3, 3A, 4, 5, 6.
2. Choose CELL Code.
Digit
1
2
3
4
2
1
2
or
4
2
or
4
3. Will you be using Analog output(s)?
If Yes, set to desired values.
If No, set to values below.
See Section:
H02 on page 42
H02
= 999.9
L02 on page 42
L02
= -9.9
4. Will you be using Alarms?
AC1
AC2
Digit
Digit
1
2
3
4
1
2
3
4
2
or
4
X
X
X
X
X
X
X
X
X
2
or
4
X
X
X
If Yes, set digits 2, 3, and 4 as desired.
If No, set AC1 = 2300
set AC2 = 2100
set Alm1= 999.9
set Alm2= –9.9
78
7. User Notes
MI 611-169 – July 2005
Dual Sensor Use
If two sensors are to be used for individual measurements, and the analog outputs used for the
two process measurements, configure, the CELL Code as indicated below. Sensor 1’s
measurement value would be displayed; both measurements would be output.
CELL Code
Digit
1
2
3
4
1
0
1
2
The two alarms could be configured as LOW Alarms, one for each of the measurements.
Alarm 1 for Sensor 1
Alarm 2 for Sensor 2
AC1
AC2
1
2
3
4
Digit
1
2
3
4
1
2
X
X
Code
2
2
X
X
Ratio:
For Ratio measurements, set CELL code as indicated below.
CELL Code
1
2
3
4
Set digits 3 and 4 as desired. If the Analog outputs will be used,
set H01, L01 and H02, L02 to the proper values. If an output
will not be used, set to:
7
0
X
X
H01 and H02 = 999.9; L01 and L02 = –9.9.
Digit
Where XX means any values.
Difference:
For Difference measurements, set CELL code as indicated below.
CELL Code
Digit
1
2
3
4
9
0
X
X
Set digits 3 and 4 as desired. If the Analog outputs will be use to
set H01, L01 and H02, L02 to the proper values. If an output
will not be used, set to:
H01 and H02 = 999.9; L01 and L02 = –9.9.
Where XX means any values.
NOTE
Calibrate individual sensors per Section 5 before setting up Ratio or Difference
measurements.
79
MI 611-169 – July 2005
7. User Notes
Redundant Sensor Operation
NOTE
Calibrate individual sensors per “Calibration” on page 59 before setting up
Redundant Sensors.
In extremely critical processes where an error in measurement could cause serious effects, two
sensors can be used as a check of measurement. CELL 1 will be designated the primary CELL
from which measurement is taken and analog output follows. The CELL code should be set:
CELL Code
Set the analog outputs as desired (digits 3 and 4 of CELL code) to
functions of CELL 1's operation. H01 and L01, H02 and L02 should
be set appropriately.
Digit
1
2
3
4
1
0
1
or
3
1
or
3
Configure an alarm, Alm1 or Alm2, to difference measurements.
AC1
AC2
Digit
Digit
Determine acceptable difference between the two
sensors before alarming.
1
2
3
4
1
2
3
4
9
X
X
X or 9
X
X
X
Set Alm1 and Alm2 and wire Alarm terminals to
appropriate Alarm device. The 873 will alarm on sensor
difference values that are out of the user's acceptable
range.
Example:
An acceptable difference between the two sensors is 2 ppm. You want to Alarm if the
difference is greater than 2 ppm. Set Alm1 to 2 ppm.
AC1
1
2
3
4
9
4
0
0
Alm2 may be used to alarm the primary sensor on CELL 1. You may want to Alarm if the
concentration drops below 2 ppm. Set AC2 as shown and Alm2 to 2 ppm.
AC2
80
1
2
3
4
1
2
0
0
7. User Notes
MI 611-169 – July 2005
Backup Sensor Operation
NOTE
Calibrate individual sensors per “Calibration” on page 59 before setting up
Redundant Sensors.
In certain applications, a second or backup sensor is installed but is not configured. Configure
CELL 1 as the primary sensor. Use the left column below. If the measurement from CELL 1 is
suspect at any time, simply enable CELL 2 as the primary CELL using the right column
configuration information.
CELL 1 Configuration
1. Wire Sensor to TB2 - CELL 1 terminals 1, 2, 3, 3A, 4, 5, 6.
2. Choose CELL Code.
Digit
1
2
3
4
1
1
1
or
3
1
or
3
3. Will you be using Analog output(s)?
If Yes, set to desired values.
If No, set to values below.
See Section:
H01 on page 42
L01 on page 42
H01
L01
= 999.9
= -9.9
4. Will you be using Alarms?
AC1
AC2
Digit
Digit
1
2
3
4
1
2
3
4
1
or
3
X
X
X
X
X
X
X
X
X
1
or
3
X
X
X
If Yes, set digits 2, 3, and 4 as desired.
If No, set AC1 = 1300
set AC2 = 1100
set Alm1 = 999.9
set Alm2 = –9.9
81
MI 611-169 – July 2005
7. User Notes
CELL 2 Configuration
1. Wire Sensor to TB5; CELL terminals 1, 2, 3, 3A, 4, 5, 6.
2. Choose CELL Code.
Digit
1
2
3
4
2
1
2
or
4
2
or
4
3. Will you be using Analog output(s)?
If Yes, set to desired values.
If No, set to values below.
See Section:
H02 on page 42
L02 on page 42
H02
L02
= 999.9
= -9.9
4. Will you be using Alarms?
AC1
AC2
Digit
Digit
1
2
3
4
1
2
3
4
2
or
4
X
X
X
X
X
X
X
X
X
2
or
4
X
X
X
If Yes, set digits 2, 3, and 4 as desired.
If No, set AC1 = 2300
set AC2 = 2100
set Alm1 = 999.9
set Alm2 = –9.9
82
8. Alarm Contact Maintenance
The alarm relay contacts are selected to switch loads equal to or greater than 20 watts. The
minimum contact current is 1 ampere. The silver alloy contacts rely on the very slight arc
generated during switching to eliminate oxide layers that form on the contacts. When the
contacts are used at low (signal) levels, contact function may become unreliable over time due to
the formation of an oxide layer on the contacts.
When contacts must be used at low levels, attention must be paid to contact condition. The
maximum contact resistance for new relays is 100 milliohms. Values above this level or unstable
values indicate deterioration of the contact surface as noted above and may result in unreliable
alarm function.
The contact surfaces can be restored as follows:
1. Disconnect the alarm wiring from the analyzer.
2. Connect a resistive load of 20 W or more (up to the maximum rating of the contacts)
as shown in Figure 23 so that both NO and NC contacts are exercised.
3. Use the analyzer to switch the alarm relay several times.
4. Disconnect the load installed in Step 2 and reconnect the wiring removed in Step 1.
5. Check to ensure that the alarms are functioning properly.
NO
C
20 W LOAD
SUPPLY VOLTAGE
NC
Figure 23. Alarm Contact Reconditioning Circuit
83
MI 611-169 – July 2005
8. Alarm Contact Maintenance
Thank you for buying an American made Invensys Foxboro 873DO Electrochemical Analyzer.
We also supply pH/ORP, resistivity, and conductivity analyzers and equipment. Contact us for
your analysis needs.
For sales information or to place an order, contact your local Invensys Foxboro distributor or local
Invensys Foxboro sales office.
For sales information or to place an order, contact your local Invensys Foxboro representative.
For Warranty Information................................................................................. 1-800-746-6477
For Electrochemistry Analyzer Repair/Troubleshooting Information ................. 508-549-2168
For Electrochemistry Technical Assistance and Application Support.................. 508-549-4730
Or by FAX ........................................................................................................ 508-549-4734
WARRANTY
Invensys Foxboro expressly warrants the products manufactured by it as meeting the
applicable Invensys Foxboro product specifications. INVENSYS FOXBORO MAKES NO
OTHER WARRANTIES EITHER EXPRESS OR IMPLIED (INCLUDING
WITHOUT LIMITATION WARRANTIES AS TO MERCHANTABILITY OR
FITNESS FOR A PARTICULAR PURPOSE). Purchaser retains responsibility for the
application and functional adequacy of the offering. In addition, the following shall
constitute the exclusive remedies for any breach by Invensys Foxboro of its warranties
hereunder.
MATERIAL, WORKMANSHIP, AND TITLE: Invensys Foxboro warrants to Purchaser
that all products manufactured by Invensys Foxboro shall be free from defects in material,
workmanship, and title, and agrees to either replace, or repair free of charge, any such
product, component, or part thereof which shall be returned to the nearest authorized
Invensys Foxboro repair facility within one (1) year from date of delivery transportation
charges prepaid for the account of the Purchaser. The cost of demonstrating the need to
diagnose such defects at the job site, if required, shall be for the account of the Purchaser.
Any product or component, or part thereof, so replaced or repaired shall be warranted by
Invensys Foxboro for the remainder of the original warranty period or three (3) months,
whichever is longer. Any and all such replacements or repairs necessitated by inadequate
preventative maintenance, or by normal wear and usage, or by the fault of the Purchaser or
power sources supplied by others or by attack and deterioration under unsuitable
environmental conditions shall be for the account of the Purchaser. Invensys Foxboro shall
not be obligated to pay any costs or charges including “back charges” incurred by the
Purchaser or any other party except as may be agreed upon in writing in advance by
Invensys Foxboro.
84
Index
A
Alarm Contact Maintenance 83
Alarm Timers (HAtt, HAFt, and HAdL) 33
Alarm Timers (LAtt, LAFt, and LAdL) 38
Analyzer Identification 5
C
Compensation and Damping (Cd) 28
Configuration 23
Configuration Setup Entries 24
Configure Mode 23
D
Diagnostics 67
Display 19
G
General Description 3
General Information Alarms 30
H
H Alarm Configuration (HAC) 31
Holding the Analog Output (HOLD) 27
I
Instrument Features 3
Introduction 1
K
Keypad 20
L
L Alarm Configuration (LAC) 36
Locking Analyzer Using Security Code 24
M
Mounting to a Panel - Metal Enclosure 10
85
MI 611-169 – July 2005
Index
Mounting to a Panel - Plastic Enclosure 9
Mounting to a Pipe (Metal Enclosure Only) 11
Mounting to a Surface, Fixed Mount (Metal Enclosure Only) 12
O
Operate Mode 22
Operation 19
Output #2's 0% Analog Value (L02) 42
S
Safety Specifications 8
Security Code 23
Sensor Diagnostics 67
Setting Alarm Level(s) 31
Specifications 6
T
Temp Key 22
Troubleshooting Tips 67
U
Unlocking Analyzer Using Security Code 24
User-Defined Lower Measurement Limit (LL)
User-Defined Lower Temperature Limit (LtL)
User-Defined Upper Measurement Limit (UL)
User-Defined Upper Temperature Limit (UtL)
40
41
40
41
V
View Setup Entries 22
W
Wiring of Metal Field-mounted Enclosure 16
Wiring of Plastic General Purpose Enclosure 16
ISSUE DATES
FEB 1993
JAN 1996
APR 1997
JUN 2004
JUL 2005
Vertical lines to right of text or illustrations indicate areas changed at last issue date.
33 Commercial Street
Foxboro, MA 02035-2099
United States of America
http://www.foxboro.com
Inside U.S.:
1-866-746-6477
Outside U.S.: 1-508-549-2424
or contact your local Foxboro
Representative.
Facsimile: (508) 549-4492
Invensys and Foxboro are trademarks of Invensys plc, its subsidiaries, and affiliates.
All other brand names may be trademarks of their respective owners.
Copyright 1993-2005 Invensys Systems, Inc.
All rights reserved
MB 123
Printed in U.S.A.
0705
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