Schneider Electric 873DO Series Electrochemical Analyzers Instruction Sheet

Instruction
MI 611-169
January 2021
873DO Series
Electrochemical Analyzers
for Dissolved Oxygen Measurement
Style C
MI 611-169 – January 2021
2
Contents
Figures ........................................................................................................................................... 7
Tables ............................................................................................................................................ 9
Important Information ................................................................................................................ 11
Please Note ...............................................................................................................................11
1. Introduction ............................................................................................................................ 13
Quick Start ...............................................................................................................................13
Sensor Wiring.......................................................................................................................13
Checking Factory Configurations .........................................................................................14
Calibration ...........................................................................................................................14
Looking for More Information .............................................................................................14
General Description ..................................................................................................................15
Instrument Features ..................................................................................................................15
Enclosures ............................................................................................................................15
Dual Alarms .........................................................................................................................15
No Battery Backup Required................................................................................................16
Instrument Security Code ....................................................................................................16
Hazardous Area Classification ..............................................................................................16
Front Panel Display ..............................................................................................................16
Front Panel Keypad ..............................................................................................................16
Application Flexibility ..........................................................................................................17
Storm Door Option .............................................................................................................17
Analyzer Identification ..............................................................................................................18
Standard Specifications..............................................................................................................19
Product Safety Specifications .....................................................................................................20
2. Installation .............................................................................................................................. 21
Mounting to a Panel – Plastic Enclosure 873DO-_ _ P.............................................................21
Mounting to a Panel - Metal Enclosure 873DO-_ _ W.............................................................22
Mounting to Pipe (Metal Enclosure Only)873DO-_ _ Y ..........................................................23
Mounting to Surface, Fixed Mount
(Metal Enclosure Only) 873DO-_ _ X ..................................................................................24
Mounting to Surface, Movable Mount
(Metal Enclosure Only) 873DO-_ _ Z ..................................................................................26
Wiring of Plastic Enclosure .......................................................................................................28
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Contents
Wiring of Metal Enclosure ........................................................................................................29
3. Operation................................................................................................................................ 31
Overview...................................................................................................................................31
Display......................................................................................................................................31
Keypad......................................................................................................................................32
Operate Mode...........................................................................................................................34
Temp Key..................................................................................................................................34
View Setup Entries....................................................................................................................35
4. Configuration.......................................................................................................................... 37
Overview...................................................................................................................................37
Configure Mode........................................................................................................................37
Security Code............................................................................................................................37
Unlocking Analyzer Using Security Code ..................................................................................38
Locking Analyzer Using Security Code......................................................................................38
Configuration Setup Entries......................................................................................................38
CELL Display and Output Configuration (CELL)...............................................................40
Holding the Analog Output (HOLD)..................................................................................41
Compensation and Damping (Cd) .......................................................................................42
General Information About Alarms ......................................................................................43
Wiring of Alarms..................................................................................................................43
Setting Alarm Setpoints ........................................................................................................44
Alarm 1 Control (AC1) ........................................................................................................45
Alarm Timers (Att1, AFt1, and AdL1)..................................................................................47
Alarm 2 Control (AC2) ........................................................................................................50
Alarm Timers (Att2, AFt2, and AdL2)..................................................................................51
User-Defined Upper Measurement Limit (UL) ....................................................................54
User-Defined Lower Measurement Limit (LL) .....................................................................54
User-Defined Upper Temperature Limit (UtL) .....................................................................55
User-Defined Lower Temperature Limit (LtL)......................................................................55
Scaling the Analog Outputs..................................................................................................55
Output #1's 100% Analog Value (H01) ...............................................................................56
Output #1's 0% Analog Value (L01) ....................................................................................56
Output #2’s 100% Analog Value (H02) ...............................................................................56
Output #2's 0% Analog Value (L02) ....................................................................................57
Basic Setup Entries ....................................................................................................................57
Unlocking Basic Setup Entries (bL) ......................................................................................58
Changing CELL Type (Ct) ...................................................................................................59
The Full Scale Range (FSC) .................................................................................................59
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Contents
MI 611-169 – January 2021
Setting Active or Electronic Zero (SErO)..............................................................................61
Setting Altitude ....................................................................................................................61
Calibrating the Current Channel (Probe Calibration; PC)....................................................61
Changing the Security Code (LCC) .....................................................................................63
Calibrating the Temperature Circuitry (tEC1, tEC2) ...........................................................64
Changing the Analog Output...............................................................................................65
To Reposition Jumpers .........................................................................................................65
Using Sensor Diagnostics .........................................................................................................70
Probe Diagnostics Enable (PdE) ...........................................................................................72
Diagnostic Learning Control (dLC) .....................................................................................72
Fouling Diagnostic Tolerance (FOt) .....................................................................................72
Membrane Cap Diagnostic Tolerance (CAt).........................................................................72
Bubble Diagnostic Tolerance (bUt).......................................................................................73
Diagnostic Timing (dt).........................................................................................................73
Diagnostic Off Window Timing (dOFF)..............................................................................73
Diagnostic On Window Timing (don) .................................................................................73
Fouling Diagnostic Lower Limit (FdLL)...............................................................................73
Drive Voltage (dr) .....................................................................................................................73
5. Calibration .............................................................................................................................. 75
Calibration of a Sensor on the 873DO - General Information ..................................................75
Startup Setup Parameters...........................................................................................................76
Units, Zero, Altitude, and Calibration Type Setup................................................................76
Temperature CELL Factor (tCF1, tCF2) ..............................................................................77
Air Calibration with Electronic Zero .........................................................................................78
Solution Calibration with Electronic Zero.................................................................................80
Solution Calibration with Solution Zero ...................................................................................81
Oxygen Solubility Tables ...........................................................................................................82
6. Diagnostics .............................................................................................................................. 83
Using the 873DO Analyzer to Troubleshoot a Sensor or Analyzer Problem ...............................83
Additional Troubleshooting.......................................................................................................84
Electronic Test for Verification of Operation of the 873DO Analyzer........................................86
Test with the CELL Simulator (Part No. BS806KM) ...........................................................86
Test with Resistors ................................................................................................................86
Error Codes...............................................................................................................................89
Detachable Configuration Field Sheet .......................................................................................91
7. User Notes............................................................................................................................... 95
Single Sensor Use ......................................................................................................................95
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MI 611-169 – January 2021
Contents
CELL 1 Configuration .........................................................................................................95
CELL 2 Configuration .........................................................................................................96
Dual Sensor Use........................................................................................................................97
Redundant Sensor Operation ....................................................................................................98
Backup Sensor Operation..........................................................................................................99
CELL 1 Configuration .........................................................................................................99
CELL 2 Configuration .......................................................................................................100
8. Alarm Contact Maintenance.................................................................................................. 101
WARRANTY..........................................................................................................................102
6
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 ..................................................................................................13
Wiring of Plastic Enclosure .................................................................................................14
Front Panel Display and Keypad .........................................................................................17
Data Label Location............................................................................................................18
Mounting to Panel - Plastic Enclosure.................................................................................21
Mounting to Panel - Metal Enclosure..................................................................................22
Metal Enclosure - Pipe Mounting........................................................................................23
Metal Enclosure - Fixed Mount...........................................................................................25
Metal Enclosure - Movable Mount......................................................................................27
Rear Panel Wiring - Plastic Enclosure..................................................................................28
Rear Panel Wiring - Metal Enclosure...................................................................................29
Model 873DO Keypad and Display....................................................................................32
Possible Alarm Wiring and Configuration Choices..............................................................44
ON/OFF relationship between Att1, AFt1, and AdL1 ........................................................48
Flow Diagram for Alarm Timer Logic .................................................................................49
ON/OFF Relationship between Att2, AFt2, and AdL2 .......................................................53
Flow Diagram for Alarm Timer Logic .................................................................................54
Current Source....................................................................................................................62
Thermistor Temperature Simulation
(Plastic Enclosure Shown) .............................................................................................65
Jumpers for Changing Analog Output ................................................................................67
Analog Output Calibration (Metal Enclosure Shown).........................................................68
Test Resistors.......................................................................................................................89
Alarm Contact Reconditioning Circuit .............................................................................101
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MI 611-169 – January 2021
8
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) .................................30
Keypad Functions ...............................................................................................................33
Configuration Setup Entries................................................................................................39
Relationship of CELL Code to Alt Cel and mA Key Function ............................................40
CELL Code – Display and Output Configuration ..............................................................41
HOLD Code - Hold Analog Output Values........................................................................42
Cd Code – Compensation and Damping ............................................................................43
AC1 Code - Alm 1 Configuration.......................................................................................47
Att1, AFt1, and AdL1 Time Codes......................................................................................48
AC2 Code - Alarm 2 Control..............................................................................................51
Att2, AFt2, and AdL2 Time Codes......................................................................................52
Basic Setup Entry Selection .................................................................................................58
Jumper Positions for the Various Analog Outputs ...............................................................66
Determining Which Sensor is Erroring ...............................................................................71
Setup Parameters .................................................................................................................71
Diagnostics Error Codes......................................................................................................71
Probe Diagnostics Enable (PdE)..........................................................................................72
Diagnostic Learn Modes......................................................................................................72
Oxygen Solubility Tables .....................................................................................................82
Error Codes.........................................................................................................................83
Temperature vs. Resistance Values .......................................................................................84
Troubleshooting Symptoms.................................................................................................85
Error/Alarm Messages .........................................................................................................90
9
MI 611-169 – January 2021
10
Tables
Important Information
Read these instructions carefully and look at the equipment to become familiar with the device
before trying to install, operate, service, or maintain it. The following special messages may
appear throughout this manual or on the equipment to warn of potential hazards or to call
attention to information that clarifies or simplifies a procedure.
The addition of either symbol to a “Danger” or “Warning” safety label
indicates that an electrical hazard exists which will result in personal injury
if the instructions are not followed.
This is the safety alert symbol. It is used to alert you to potential personal injury
hazards. Obey all safety messages that follow this symbol to avoid possible injury or
death.
DANGER
DANGER indicates a hazardous situation which, if not avoided, will result in death or serious
injury.
!
WARNING
WARNING indicates a hazardous situation which, if not avoided, could result in death or
serious injury.
!
CAUTION
CAUTION indicates a hazardous situation which, if not avoided, could result in minor or
moderate injury.
!
NOTICE
NOTICE is used to address practices not related to physical injury.
Please Note
Electrical equipment should be installed, operated, and maintained only by qualified personnel.
No responsibility is assumed by Schneider Electric for any consequences arising out of the use of
this material.
A qualified person is one who has skills and knowledge related to the construction, installation,
and operation of electrical equipment and has received safety training to recognize and avoid the
hazards involved.
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MI 611-169 – January 2021
12
Important Information
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 28 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
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MI 611-169 – January 2021
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 39 and Table 12, “Basic Setup Entry Selection,” on page 58. 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 78 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 21. For dimensional information,
refer to DP 611-163.
For detailed explanation of the controls and indicators, refer to “Operation” on page 31.
For detailed configuration instructions, refer to “Configuration” on page 37.
For detailed calibration instructions, refer to “Calibration” on page 75.
If you need additional help, please contact Global Customer Support.
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1. Introduction
MI 611-169 – January 2021
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.
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MI 611-169 – January 2021
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 101.
!
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 20.
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.
16
1. Introduction
MI 611-169 – January 2021
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.
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
8.8.8.8.
Temp
Shift
Cal Hi
Alt Cel
Alm 1
Next
Cal Lo
Setup
Alm 2
Lock
Measurement
Legend Units
Display
uA
%
Cel 2 ppm
uA
Single Function Key
(Press key only)
Enter
Figure 3. Front Panel Display and Keypad
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MI 611-169 – January 2021
1. Introduction
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
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1. Introduction
MI 611-169 – January 2021
Standard Specifications
Supply Voltages
–A
–B
–C
–E
–J
Supply Frequency
50 or 60, ±3 Hz
Output Signal
I
T
E
Ambient Temperature Limits
–25 to +55°C (–13 to +131°F)
Measurement Ranges
0 to 100.0% Oxygen Saturation
0 to 25.00% Oxygen in Air
0 to 100.0 ppm
0 to 100.0 (no units)
Temperature Measurement Range
–17 to +120°C (0 to 250°F) w/100 KW thermistor
Temperature Compensation Range
0 to 50°C (32 to 122°F)
Relative Humidity Limits
5 to 95%, noncondensing
Accuracy of Analyzer
±0.5% of upper range limit
Analyzer Identification
Refer to Figure 4.
Dimensions
Plastic Enclosure 92(H) x 92(W) x 183(L) mm
Metal Enclosure 92(H) x 92(W) x 203(L) mm
Enclosure/Mounting Options
–P
–W
–X
–Y
–Z
Approximate Mass
Plastic General Purpose Enclosure
Metal Field Enclosure (with Brackets)
Panel Mounting
Pipe Mounting
Fixed Surface Mounting
Movable Surface Mounting
120 V ac
220 V ac
240 V ac
24 V ac
100 V ac
4 to 20 mA isolated
0 to 10 V dc isolated
0 to 20 mA isolated
Plastic General Purpose Panel Mount
Metal Field Panel Mount
Metal Field Surface Mount
Metal Field Pipe Mount
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)
Instrument Response (Analyzer Only)
Two seconds maximum (when zero measurement damping is
selected in Configuration Code). Temperature response is 15
seconds maximum.
Measurement Damping
Choice of 0, 10, 20, or 40 second, configurable from keypad.
Damping affects displayed parameters and analog outputs.
Alarms
Alarm Contacts
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 101.
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MI 611-169 – January 2021
1. Introduction
Alarm Indication
Alarm status alternately displayed with measurement on LED
display.
RFI Susceptibility
(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
Plastic General Purpose Enclosure:
Metal Field Enclosure:
Electromagnetic Compatibility (EMC)
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.
Product Safety Specifications
Testing Laboratory,
Types of Protection,
and Area Classification
FM for use in general purpose (ordinary)
locations.
Application Conditions
---
FM nonincendive for use in Class I, II, Division 2, For instruments with metal enclosure only.
groups A, B, C, D, F, and G, hazardous locations. Temperature Class T6.
CSA (Canada) for use in general purpose
(ordinary) locations.
Electrical
Safety Design Code
FGZ
FNZ
24 V, 100 V, and 120 V ac (Supply Option -Al, CGZ
-E, -J) only.
CSA (Canada) suitable for use in Class I, Division For instruments with metal enclosure only.
CNZ
2, Groups A, B, C, and D, hazardous locations.
24 V, 100 V, and 120 V ac (Supply Option -A,
-E, -J) only.
Temperature Class T6.
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 Global
Customer Support.
! 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 Schneider Legacy Relay 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.
20
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
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MI 611-169 – January 2021
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
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2. Installation
MI 611-169 – January 2021
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
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MI 611-169 – January 2021
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.
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2. Installation
MI 611-169 – January 2021
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
25
MI 611-169 – January 2021
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.
26
2. Installation
MI 611-169 – January 2021
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
27
MI 611-169 – January 2021
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 43.
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 95 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
28
+
2. Installation
MI 611-169 – January 2021
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.
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 43.
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 95 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
29
MI 611-169 – January 2021
2. Installation
Table 1. Recommended Conduit and Fitting (Due to Internal Size Restraints)
Conduit
Fitting
Rigid Metal
1/2-inch Electrical Trade Size
T&B* #370
Semi-rigid Plastic
T&B #LTC 050
T&B* #LT 50P or T&B #5362
Semi-rigid Plastic, Metal Core
Anaconda Type HC, 1/2-inch
T&B* #LT 50P or T&B #5362
Flexible Plastic
T&B #EFC 050
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.
30
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 , 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.
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MI 611-169 – January 2021
3. Operation
Keypad
The keypad, Figure , 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
Cal Hi
KEYPAD
Temp
Shift
Alt Cel
Alm 1
Next
Cal Lo
Setup
Alm 2
Lock
μA
%
Cel
2
ppm
μA
Enter
Figure 12. Model 873DO Keypad and Display
32
ENGINEERING
UNITS ARE
BACKLIT. ONLY
THE ONE
CONFIGURED
IS VISIBLE.
3. Operation
MI 611-169 – January 2021
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.
μA
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.
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.
Alt Cel
Next
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.
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: 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.
Cal Hi
Alm 1
NOTE
1. Pressing Next and Δ 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
33
MI 611-169 – January 2021
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 38), the Temp key, used in conjunction with the increment (Δ) 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 Δ 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 Δ to display the
new value; then push Enter. Automatic temperature compensation cannot be adjusted by this
procedure. See “Startup Setup Parameters” on page 76. To return to automatic compensation,
sequence the display to remove the decimal point after C or F.
34
3. Operation
MI 611-169 – January 2021
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 37.
35
MI 611-169 – January 2021
36
3. Operation
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 39 lists all the
parameters that are more frequently changed, and Table 12, “Basic Setup Entry Selection,” on
page 58 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 38). 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 57).
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.
37
MI 611-169 – January 2021
4. Configuration
When the unit is unlocked at the first level (see “Unlocking Analyzer Using Security Code” on
page 38), the unit will remain unlocked until a positive action is taken to lock the unit again (see
“Locking Analyzer Using Security Code” on page 38).
However, when the unit is unlocked using the bL entry at the second level of security (see
“Unlocking Basic Setup Entries (bL)” on page 58), 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 (Δ) 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 (Δ) 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.
38
4. Configuration
MI 611-169 – January 2021
Table 3. Configuration Setup Entries
Displayed
Symbol
Reference
(Page No.)
CELL
40
Hold
Cd
AC1
Parameters and Values Accessed
Factory
Default
Configuration of Display, Analog Outputs
1113
41
Holds and sets the Analog Output Value in Hold
0000
42
Compensation and Damping
- Damping Factor
- Temperature Compensation
0001
45
Alarm 1 Control
- Measurement Selection
- Low/High/Instrument plus Passive/Active State
- % Hysteresis
1403
Att1
51
Alarm 1 Trigger Timer
00.00
AFt1
47
Alarm 1 Feed Time
00.00
AdL1
47
Alarm 1 Delay Time
00.00
AC2
50
Alarm 2 Control
- Measurement Selection
- Low/High/Instrument plus Passive/Active State
- % Hysteresis
1203
Att2
51
Alarm 2 Trigger Timer
00.00
AFt2
51
Alarm 2 Feed Time
00.00
AdL2
51
Alarm 2 Delay Time
00.00
UL
54
User-defined Upper Measurement Limit - Both CELLS
per sales
order
LL
54
User-defined Lower Measurement Limit - Both CELLS
0.00
UtL
55
User-defined Upper Temperature Limit - Both CELLS
100.0
LtL
55
User-defined Lower Temperature Limit - Both CELLS
0.00
HO1
56
100% Analog Output - Channel 1
per sales
order
LO1
56
0% Analog Output - Channel 1
0.00
HO2
56
100% Analog Output - Channel 2
100°C
LO2
57
0% Analog Output - Channel 2
0°C
User
Settings
To change any of the Configuration Setup parameters, use the following procedure:
1. Unlock Analyzer (see “Unlocking Analyzer Using Security Code” on page 38).
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 Δ until the desired code or value is displayed.
6. Press Enter.
7. Lock Analyzer (see “Locking Analyzer Using Security Code” on page 38).
NOTE
To prevent timeout at any time during this procedure, press and hold the Shift key.
39
MI 611-169 – January 2021
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
values of:
CELL 2
CELL 1
CELL 1 and 2
CELL 1 and 2
-
Press μA to display μA
value of:
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 95.
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 95.
Digits 3 and 4 Configurations:
Two analog outputs are available on the 873DO. Signal assignments for these outputs are shown
in Table 5.
40
4. Configuration
MI 611-169 – January 2021
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 95.
Table 5. CELL Code – Display and Output Configuration
Digit 1
Digit 2
Digit 3
Digit 4
DISPLAY
OPERATION
OUTPUT 1
OUTPUT 2
1 - Cell 1
2 - Cell 2
7 - Ratio
9 - Difference
0 - Interrogate both
channels
1 - Ignore nonconfigured channel
1 - Dissolved Oxygen Cell 1
2 - Dissolved Oxygen Cell 2
3 - Temp Cell 1
4 - Temp Cell 2
7 - Ratio
9 - Difference
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
41
MI 611-169 – January 2021
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 - 0.5
5.5
----------------------- 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 56 and “Output #1's 0% Analog Value (L01)” on page 56 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 59. 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 75) 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 82.
42
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
MI 611-169 – January 2021
02
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)
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 101.
!
Wiring of Alarms
Alarm relay locations may be found in “Wiring of Plastic Enclosure” on page 28 and “Wiring of
Metal Enclosure” on page 29 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.
43
MI 611-169 – January 2021
4. Configuration
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
C
NC
NO
ALARM INDICATION
ON LOCAL DISPLAY
C
ON
NC
Figure 13. Possible Alarm Wiring and Configuration Choices
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 45 and “Alarm 2 Control (AC2)” on page 50.
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 38).
2. To set alarm 1, press Alm1. Then use Next and Δ to achieve the desired value on the
display. Press Enter.
44
4. Configuration
MI 611-169 – January 2021
3. To set alarm 2, press Alm2. Then use Next and Δ to achieve the desired value on the
display. Press Enter.
4. Lock Analyzer (see “Locking Analyzer Using Security Code” on page 38).
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 28 and “Wiring of Metal Enclosure” on page 29 of this document.
45
MI 611-169 – January 2021
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 54 and “User-Defined
Lower Temperature Limit (LtL)” on page 55.
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 70 through 73 for information about
programming these diagnostics.
Refer to the “Error Codes” on page 89, 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.
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.
46
4. Configuration
MI 611-169 – January 2021
Table 8. AC1 Code - Alm 1 Configuration
Digit 1
Digit 2
Digits 3 and 4
MEASUREMENT SELECTION
CONFIGURATION
HYSTERESIS
1 - Dissolved Oxygen CELL 1
2 - Dissolved Oxygen CELL2
3 - Temp CELL 1
4 - Temp CELL 2
7 - % Ratio
9 - Difference
1 = Low/Passive
2 = Low/Active
3 = High/Passive
4 = High/Active
5 = Instrument/Passive
6 = Instrument/Active
7 = HOLD/Passive
8 = HOLD/Active
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.
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.
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MI 611-169 – January 2021
4. Configuration
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
Digit 3
00 to 99 minutes
Digit 4
0 to 9 tenths of minutes
TIME (MINUTES)
0 to 9 hundredths of 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
MINUTES
Figure 14. ON/OFF relationship between Att1, AFt1, and AdL1
48
70
4. Configuration
MI 611-169 – January 2021
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).
d. 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.
e. 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.
No
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
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MI 611-169 – January 2021
4. Configuration
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 28 and
page 29 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.
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 54 through “User-Defined
Lower Temperature Limit (LtL)” on page 55.
NOTE
In addition to these diagnostics, diagnostic information for membrane coating,
breakage, or electrolyte problems in the 871DO is available. See pages 70 through 73
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 89 for identifying error messages.
50
4. Configuration
MI 611-169 – January 2021
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
Digit 2
Digits 3 and 4
MEASUREMENT SELECTION
CONFIGURATION
HYSTERESIS
1 - Dissolved Oxygen CELL 1
2 - Dissolved Oxygen CELL 2
3 - Temp CELL 1
4 - Temp CELL 2
7 - % Ratio
9 - Difference
1- Low/Passive
2 = Low/Active
3 = High/Passive
4 = High/Active
5 = Instrument/Passive
6 = Instrument/Active
7 = HOLD/Passive
8 = HOLD/Active
00 to 99% of Full Scale
0.0 to 9.9 (% mode)
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.
51
MI 611-169 – January 2021
4. Configuration
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
Table 11. Att2, AFt2, and AdL2 Time Codes
Digits 1 and 2
00 to 99 minutes
52
Digit 3
0 to 9 tenths of minutes
Digit 4
0 to 9 hundredths of minutes
4. Configuration
MI 611-169 – January 2021
SETPOINT
g
b
h
i
MEASUREMENT
ON
c
a
f
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).
d. 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.
e. 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.
53
MI 611-169 – January 2021
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 89), 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
The UL value is preconfigured which is 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.
54
4. Configuration
MI 611-169 – January 2021
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 89) 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. The LtL value is preconfigured 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.
55
MI 611-169 – January 2021
4. Configuration
The user may wish to “reverse” the analog output signal in some situations.
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 40. The H01 value is
preconfigured 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 40. The 0% value is preconfigured
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 Δ to display
40°C. The correct units will appear if CELL is configured correctly. Press Enter.
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4. Configuration
MI 611-169 – January 2021
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 Δ
to display 0°C. The correct units will appear if CELL is configured properly. Press Enter.
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.
57
MI 611-169 – January 2021
4. Configuration
Table 12. Basic Setup Entry Selection
Display
Symbol
bL
Section
58
Parameter and Value Accessed61
Basic Setup Lock Control
Factory Default
User
Settings
0800
Ct
59
Sensor CELL Type
0004
FSC
59
Full Scale Value
100 ppm
SEr0
61
Zero Calibration
0001
ALt
61
Altitude Calibration
0000
PC
61
Probe Calibration
0000
LCC
63
Lock Change Code
0800
tCF1
64
Temperature CELL Factor CELL 1
25.00
tEC1
64
Temperature Electronics Calibration CELL 1
25.00
tCF2
64
Temperature CELL Factor CELL 2
25.00
tEC2
64
Temperature Electronics Calibration CELL 2
25.00
LC01
65
Low Calibration Analog Output 1
00.00
HC01
65
High Calibration Analog Output 1
100.0
LC02
65
Low Calibration Analog Output 2
00.00
HC02
65
High Calibration Analog Output 2
100.0
PdE
72
Probe Diagnostic Enable
0000
dLC
72
Diagnostic Learning Control
0000
FOt
72
Fouling Diagnostic Tolerance
0050
CAt
72
Membrane Cap Diagnostic Tolerance
0020
bUt
73
Bubble Diagnostic Tolerance
0020
dt
73
Diagnostic Interval Timing
0060
dOFF
73
Diagnostic Off Window Timing
2.000
don
73
Diagnostic On Window Timing
2.000
FdLL
73
Fouling Diagnostic Lower Limit
001.0 μA
dr
73
Drive Voltage Setting
00.70
Display Symbols Sft, SOH, and SOL appear in the display but are not configurable.
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 38).
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 Δ until security code is displayed (0800 from factory).
6. Press Enter. ULOC appears on the display.
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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 Δ 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 38).
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 75.
Procedure to Change Ct:
Unlock bL by following procedure in “Unlocking Basic Setup Entries (bL)” on page 58. 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 Δ . The
code alternates between 0002, 0003, and 0004 with repeated pressing of Δ . 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.
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
(mg/l)
100.0%
(percent of air)
25.0%
(no units)
(percent saturation)
100.0
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4. Configuration
The 100.0 ppm FSC requires additional temperature compensation be set via the Cd Setup
parameter (see “Compensation and Damping (Cd)” on page 42). 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.
♦ The FSC value is preconfigured 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 38).
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).
4. Press Enter, then use Next and Δ 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.
!
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7. Press Δ 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 75.
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 58. 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 Δ . The code alternates between 0000, and 0001 with repeated pressing of Δ . When
the correct value is displayed, press Enter.
The 873DO analyzer is preconfigured to read 0001 for this parameter. Sensors will require
recalibration after changing this parameter. See “Calibration” on page 75.
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.
The 873DO analyzer is preconfigured to read 0000 for this parameter unless ordered differently.
Sensors may require recalibration after changing this parameter. See the section on Calibration on
page 75.
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.
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4. Configuration
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 86 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).
3. Unlock Analyzer using security code (see “Unlocking Analyzer Using Security Code”
on page 38).
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 Δ 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.
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8. Unlock bL by following procedure in “Unlocking Basic Setup Entries (bL)” on
page 58.
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 Δ . The code alternates between 0000, and
0001 with repeated pressing of Δ .
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 Δ 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 Δ 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 Δ 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 58. 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 61). Press Enter.
21. When the display returns to SErO, press Next two times to display the parameter PC.
Press Enter.
22. Use Next and Δ until the display reads 0000. Press Enter.
23. Change Cd code to desired values. See “Compensation and Damping (Cd)” on
page 42.
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 75.
25. Lock Analyzer using security code (see “Locking Analyzer Using Security Code” on
page 38).
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 Global Customer Support.
1. Leave power on.
2. Press Lock. Display will show either Loc or uLoc.
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4. Configuration
3. If uLoc is displayed, proceed to Step 4.
If Loc is displayed, unlock the analyzer using “Unlocking Analyzer Using Security
Code” on page 38. 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 Δ 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 ( Δ ) 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 38.
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 77 and “Entering a tCF
Value” on page 78.
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.
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 Δ 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.
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4. Configuration
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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 68.
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.
!
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4. Configuration
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
Output
Current
Voltage
4-20 mA
or
0-20 mA
0-10 V dc
J5
J6
J7
J10
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 68.
10. Make appropriate changes to the analyzer identification label.
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4. Configuration
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FDOA
RVOA
AS700FC-OA
Jumper Positions for the Various Analog Outputs
Output
Current
Voltage
4-20 mA
or
0-20 mA
0-10 V dc
J5
J6
J7
J10
2-3
2-3
2-3
2-3
1-2
1-2
1-2
1-2
Figure 20. Jumpers for Changing Analog Output
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4. Configuration
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 29.
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 28.
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 Δ 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
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4. Configuration
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Example:
(3.78 – 4.00mA)
--------------------------------------------- x 100 = – 1.1%
(20.00 mA)
8. Use Next and Δ 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 Δ 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 Δ 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.
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4. Configuration
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:
Observed Reading
% = -------------------------------------------- x 100
Desired Reading
Example
10.42 V
-------------------- x 100 = 104.2%
10.00
17. Use Next and Δ 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 38.
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 Global Customer
Support.
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To utilize all of the sensor diagnostic features, the following criteria must be met:
♦ A Foxboro 871DO Dissolved Oxygen Sensor must be used.
♦ CELL Type Parameter (Ct) must be set to 4. (See “Changing CELL Type (Ct)” on
page 59.)
♦ Probe Diagnostic Enable (PdE) must be set to 0111.
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
1
2
12
Sensor Erroring
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
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
Code
0000
0000
0050
0020
0020
0060
2.000
2.000
1.000
Table 16. Diagnostics Error Codes
Error Code
Cause
COAt
Membrane of the sensor has become coated and requires cleaning or servicing.
CAP
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.
bubL
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.
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4. Configuration
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
Digit 4
COAt diagnostics
CAP diagnostics
bubL diagnostics
0 - Diagnostics Off
1 - Diagnostics On
0 - Diagnostics Off
1 - Diagnostics On
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 73). 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.
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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.
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4. Configuration
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 77). 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 78 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 80 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 81 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 38).
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 Δ 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 Δ until the desired unit of measurement is displayed.
See “The Full Scale Range (FSC)” on page 59.
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 61.
10. Press Enter, then use Δ 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 61.
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5. Calibration
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13. Press Enter, then use Δ and Next to make display read the Altitude (in feet above sea
level) at which the sensor will be operated.
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 Δ 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 28 or “Wiring
of Metal Enclosure” on page 29.
18. When using two sensors, configure pertinent parameters to appropriate values. See
“User Notes” on page 95 and “Configuration” on page 37 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 77 and “Entering a tCF
Value” on page 78 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 40.
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 Δ 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.
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5. Calibration
6. This procedure should be repeated with the second sensor, if used. See CELL code
(“CELL Display and Output Configuration (CELL)” on page 40).
Entering a tCF Value
1. Unlock Analyzer (see“Unlocking Analyzer Using Security Code” on page 38).
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 Δ 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 Δ until desired value (see “Determining tCF” on
page 77) 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 38.
Air Calibration with Electronic Zero
NOTE
The following start-up parameters must be set first (see “Startup Setup Parameters” on
page 76).
(If FSC = 100 ppm)
FSC
100%, 25%
100 ppm, 100
→
SEr0
0001
→
ALt
→
tCF
→
Cd
0000
1. Unlock Analyzer if locked (see “Unlocking Analyzer Using Security Code” on
page 38).
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 40. 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 42. Set this code to read “0000”.
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5. Calibration
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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.)
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 Δ 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 82 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 42.
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 42.
12. Lock Analyzer (see “Locking Analyzer Using Security Code” on page 38).
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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 76):
(If FSC = 100 ppm)
FSC
100%, 25%
100 ppm, 100
→
SEr0
0001
→
ALt
→
tCF
→
Cd
000X
0001
0002
1. Unlock Analyzer if locked (see “Unlocking Analyzer Using Security Code” on
page 38).
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 40. 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 42. 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 Δ 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 42.
11. Lock Analyzer (see “Locking Analyzer Using Security Code” on page 38).
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5. Calibration
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Solution Calibration with Solution Zero
NOTE
The following start-up parameters must be set first (see “Startup Setup Parameters” on
page 76):
FSC
100%, 25%
100 ppm, 100
→
SEr0
0000
→
ALt
→
(If FSC = 100 ppm)
tCF
→ Cd
000X
0001
0002
1. Unlock Analyzer if locked (see “Unlocking Analyzer Using Security Code” on
page 38).
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 40. 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 42. 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 Δ 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 Δ 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 38).
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
82
Temp
°F
Fresh Water
(ppm)
Temp
°C
Temp
°F
Fresh Water
(ppm)
0
32.0
14.6
26
78.8
8.2
1
33.8
14.2
27
80.6
8.0
2
35.6
13.8
28
82.4
7.8
3
37.4
13.4
29
84.2
7.7
4
39.2
13.1
30
86.0
7.6
5
41.0
12.7
31
87.8
7.4
6
42.8
12.4
32
89.6
7.4
7
44.6
12.1
33
91.4
7.2
8
46.4
11.8
34
93.2
7.1
9
48.2
11.5
35
95.0
7.0
10
50.0
11.3
36
96.8
6.9
11
51.8
11.0
37
98.6
6.8
12
53.6
10.7
38
100.4
6.7
13
55.4
10.5
39
100.4
6.6
14
57.2
10.3
40
104.0
6.5
15
59.0
10.1
41
105.8
6.4
16
60.8
9.8
42
107.6
6.3
17
62.6
9.6
43
109.4
6.2
18
64.4
9.4
44
111.2
6.1
19
66.2
9.2
45
113.0
6.0
20
68.0
9.1
46
114.8
5.9
21
69.8
8.9
47
116.6
5.8
22
71.6
8.7
48
118.4
5.7
23
73.4
8.6
49
120.2
5.6
24
75.2
8.4
50
122.0
5.5
25
77.0
8.2
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
Enter LCC twice to restart the analyzer.
Disconnect sensor and re-power analyzer.
Try sensor on another unit or other channel.
Er 2
Temperature Error; the temperature sensor
used on the 873 is a 100 k W thermistor. At
temperatures around 25°C (77°F), it should
read 100 k W. The sensor or 873 Analyzer
may be at fault.
Verify that instrument is functioning properly.
(1) Check temperature on both channels in automatic
temperature compensation mode (See “Temp Key” on
page 34). 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.
Er 4
Er 4 flashes when the 873 Analyzer is not
calibrated after changing the Ct code or
FSC.
Calibration with sensor is necessary. Both channels must be
calibrated. See “Calibration” on page 75.
COAt
Sensor membrane has become coated with Clean sensor.
a film.
Replace membrane.
Reset PdE; relearn dLC (see page 72).
CAP
Sensor membrane has become damaged. Replace membrane.
Process ingress into electrolyte reservoir.
Examine membrane, replace if necessary.
Replace electrolyte.
Reset PdE; relearn dLC (see page 72).
bubL
Loss of electrolyte.
Examine membrane, replace if necessary.
Excess AgCl buildup on auxiliary electrode. Replace electrolyte.
Replace sensor.
Reset PdE; relearn dLC (see page 72).
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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
23
32
50
68
77
86
461.550 kΩ
351.020 kΩ
207.850 kΩ
126.740 kΩ
100.000 kΩ
79.422 kΩ
40
50
60
70
80
90
104
122
140
158
176
194
51.048 kΩ
33.591 kΩ
22.590 kΩ
15.502 kΩ
10.837 kΩ
7.7077 kΩ
100
105
110
120
130
150
212
221
230
248
266
302
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
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Table 22. Troubleshooting Symptoms
Problem
Cause
Remedy
Display LEDs not
functioning
Wiring/Power Connection
Analyzer Defective
-Verify that line power and wiring are correct.
-Replace.
Sensor/873DO
cannot be calibrated
Defective sensor
-Replace electrolyte.
-Replace membrane cap.
-Replace sensor.
-Verify patch cable OK.
Reading sensitive to
sensor motion
Recent membrane cap
replacement
-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
Temperature reading Calibration incorrect
is incorrect
Thermistor or wire broken
-Adjust tCF1 or tCF2.
-Check sensor leads 1 and 2 vs. values in Table 21.
-Also, see Er 2 in Table 20.
Slow response
Electrolyte depleted
-Replace electrolyte in sensor.
Membrane coated or Insufficient -Replace electrolyte and membrane cap.
membrane tension
Sensor inoperative
-Replace sensor.
Reading extremely
high
Damaged membrane
Ground loop
-Replace electrolyte and membrane cap.
-See below.
Ground loop
Dual sensors
calibrate OK in air but
are erratic in process
-Check membrane for leakage. Replace cap.
-Check for electrolyte leakage above cap. Replace
O-ring.
-Check electrolyte vent for leakage. Reseal vent cap.
Noisy signal
-Check Analyzer noise by simulating sensor signal
with a resistor (See “Electronic Test for Verification of
Operation of the 873DO Analyzer” on page 86).
-Increase damping.
-Reorient sensor.
-ECS cleaner not adjusted correctly.
-Solution extremely turbulent. Reorient sensor and
place in weir.
-Replace membrane cap.
May be flow related
Insufficient membrane tension
Accuracy
Sensor membrane coated
-Accuracy of sensor may be affected by coating or films.
Consult sensor MI for cleaning recommendations.
Reading extremely
high. Current (μA)
elevated also.
Application problem
Older style analyzer
Older style sensor
-Replace electrolyte and membrane cap.
-Verify analyzer is Style CE.
-Verify Style B; 871DO - C Style B sensor.
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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 34.
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 34. 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 40.
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 34.
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6. Diagnostics
MI 611-169 – January 2021
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.
22. Place a short between 3 and 5.
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6. Diagnostics
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 34.
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 40.
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6. Diagnostics
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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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6. Diagnostics
Table 23. Error/Alarm Messages
Alternate
Display
Condition
Priority
Action Required to Clear Error Message
Er 1
Instrument fault, RAM/ROM, software
watchdog timer
1
(Highest)
1. Reenter LCC using procedure on page 63.
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.
Er 2
User-defined temperature range error or
temperature measurement error
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 “Using the 873DO Analyzer to Troubleshoot a Sensor or Analyzer Problem” on
page 83.
Er 3
User-defined measurement range error
7
1. Change user-defined measurement limits,
UL or LL.
2. Replace sensor.
3. Ground loop (see Table 22).
Er 4
Measurement calibration incorrect
2
Recalibrate sensors on both channels.
AL 1
Alarm 1 condition triggered
9
AL 2
Alarm 2 condition triggered
9
A1A2
Both alarms are triggered simultaneously 8
····
Measurement over or under range of
analog output limits
10
Err
Incorrect code or parameter attempted
2
Check code and reenter.
COAt
Membrane fouled
4
1. Clean sensor.
2. Replace membrane.
CAP
Broken membrane; process ingress into
electrolyte
3
Replace membrane cap and electrolyte.
bubL
AgCl coating on auxiliary electrode
Air bubble in electrolyte
Low electrolyte
5
Replace sensor.
Refill 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.
90
6. Diagnostics
MI 611-169 – January 2021
Detachable Configuration Field Sheet
Configuration Setup Entries
Symbol
Parameters and Values Accessed
CELL
Configuration of Display, Analog Outputs
Hold
Hold and sets the Analog output value in Hold
Cd
Compensation and Damping
– Damping Factor
– Temperature Compensation
AC1
Alarm 1 Control
– Measurement Selection
– Low/High/Instrument plus Passive/Active State
– % Hysteresis
Att1
Alarm 1 Trigger Timer
AFt1
Alarm 1 Feed Time
AdL1
Alarm 1 Delay Time
AC2
Alarm 2 Control
– Measurement Selection
– Low/High/Instrument plus Passive/Active State
– % Hysteresis
Att2
Alarm 2 Trigger Timer
AFt2
Alarm 2 Feed Time
AdL2
Alarm 2 Delay Time
UL
User-Defined Upper Measurement Limit - Both CELLs
LL
User-Defined Lower Measurement Limit - Both CELLs
UtL
User-Defined Upper Temperature Limit - Both CELLs
LtL
User-Defined Lower Temperature Limit - Both CELLs
HO1
100% Analog Output - Channel 1
LO1
0% Analog Output - Channel 1
HO2
100% Analog Output - Channel 2
LO2
0% Analog Output - Channel 2
User Settings
91
MI 611-169 – January 2021
6. Diagnostics
Basic Setup Entry Selection
Symbol
Parameter and Value Accessed
bL
Basic Setup Lock Control
Ct
Sensor CELL Type
FSC
Full Scale Value
SEr0
Zero Calibration
ALt
Altitude Calibration
PC
Probe Calibration
LCC
Lock Change Code
tCF1
Temperature CELL Factor CELL 1
tEC1
Temperature Electronics Calibration CELL 1
tCF2
Temperature CELL Factor CELL 2
tEC2
Temperature Electronics Calibration CELL 2
LC01
Low Calibration Analog Output 1
HC01
High Calibration Analog Output 1
LC02
Low Calibration Analog Output 2
HC02
High Calibration Analog Output 2
PdE
Probe Diagnostic Enable
dLC
Diagnostic Learning Control
FOt
Fouling Diagnostic Tolerance
CAt
Membrane Cap Diagnostic Tolerance
bUt
Bubble Diagnostic Tolerance
dt
Diagnostic Interval Timing
dOFF
Diagnostic Off Window Timing
don
Diagnostic On Window Timing
FdLL
Fouling Diagnostic Lower Limit
dr
Drive Voltage Setting
User Settings
CELL Code - Display and Output Configuration
Digit 1
Digit 2
Digit 3
DISPLAY
1-CELL 1
2-CELL 2
7-Ratio
9-Difference
0-Interrogate both
channels
1-Ignore non- configured
channel
Digit 4
OUTPUT 1
OUTPUT 2
1-Dissolved Oxygen CELL 1
2-Dissolved Oxygen CELL 2
3-Temp CELL 1
4-Temp CELL 2
7-Ratio
9-Difference
1-Dissolved Oxygen CELL 1
2-Dissolved Oxygen CELL 2
3-Temp CELL 1
4-Temp CELL 2
7-Ratio
9-Difference
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
92
Digits 2, 3, and 4
000 to 100% of Analog Output Range
6. Diagnostics
MI 611-169 – January 2021
Cd Code - Compensation and Damping
Digit 1
Digit 2
Digits 3 and 4
Damping
ppm Temperature Compensation
0
0 = none
1 = 10 seconds
2 = 20 seconds
3 = 40 seconds
00=% Saturation
01=Pure Water
02=Saltwater
AC1 and AC2 Codes - Alarm Control
Digit 1
Digit 2
Digits 3 & 4
MEAS. SELECTION
CONFIGURATION
HYSTERESIS
1 – Diss. Oxygen CELL 1
2 – Diss. Oxygen CELL 2
3 – Temp CELL 1
4 – Temp CELL 2
7 – % Ratio
9 – Difference
1 – Low/Passive
2 – Low/Active
3 – High/Passive
4 – High/Active
5 – Instrument/Passive
6 – Instrument/Active
7 – Hold/Passive
8 – Hold/Active
00 to 99% of Full Scale
0.0 to 9.9% (% mode)
AFt1, AdL1, AFt2, AdL2, Att1 and Att2 Time Codes
Digits 1 and 2
00 to 99 minutes
Digit 3
0 to 9 tenths of minutes
Digit 4
0 to 9 hundredths of minutes
93
MI 611-169 – January 2021
6. Diagnostics
Error/Alarm Messages
Alternate
Display
Condition
Priority
Action Required to Clear Error Message
Er 1
Instrument fault, RAM/ROM, software
watchdog timer
1. Reenter LCC using procedure onpage 63.
1
(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.
Er 2
User-defined temperature range error or
temperature measurement error
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.
Er 3
User-defined measurement range error
7
1. Change user-defined measurement limits,
UL or LL.
2. Replace sensor.
3. Ground loop (see Table 22).
Er 4
Measurement calibration incorrect
2
1. Recalibrate sensors on both channels.
AL 1
Alarm 1 condition triggered
9
AL 2
Alarm 2 condition triggered
9
A1A2
Both alarms are triggered simultaneously
8
²²²²
Measurement over or under range of analog
output limits
10
Err
Incorrect code or parameter attempted
2
Check code and reenter.
COAt
Membrane fouled
4
1. Clean sensor.
2. Replace membrane.
CAP
Broken membrane; process ingress into
electrolyte
3
Replace membrane cap and electrolyte.
bubL
AgCl coating on auxiliary electrode
Air bubble in electrolyte
Low electrolyte
5
Replace sensor.
Refill 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.
94
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 56
H01 = 999.9
L01 on page 56
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
95
MI 611-169 – January 2021
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 56
H02
= 999.9
L02 on page 57
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
96
7. User Notes
MI 611-169 – January 2021
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
Digit
1
2
3
4
7
0
X
X
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:
H01 and H02 = 999.9; L01 and L02 = –9.9.
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
Where XX means any
values.
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.
NOTE
Calibrate individual sensors per Section 5 before setting up Ratio or Difference
measurements.
97
MI 611-169 – January 2021
7. User Notes
Redundant Sensor Operation
NOTE
Calibrate individual sensors per “Calibration” on page 75 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
1
2
3
4
9
X
X
X
or
Determine acceptable difference between the two
sensors before alarming.
1
2
3
4
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
98
1
2
3
4
1
2
0
0
7. User Notes
MI 611-169 – January 2021
Backup Sensor Operation
NOTE
Calibrate individual sensors per “Calibration” on page 75 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 56
L01 on page 56
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
99
MI 611-169 – January 2021
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 56
L02 on page 57
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
100
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
20 W LOAD
C
SUPPLY VOLTAGE
NC
Figure 23. Alarm Contact Reconditioning Circuit
Thank you for buying an American made 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 Global Customer Support
For sales information or to place an order, contact Global Customer Support.
For Warranty Information1-800-746-6477
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
101
MI 611-169 – January 2021
8. Alarm Contact Maintenance
WARRANTY
The Manufacturer expressly warrants the products manufactured by it as meeting the
applicable product specifications. NO OTHER WARRANTIES EITHER EXPRESS
OR IMPLIED ARE MADE(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 of the warranties hereunder.
MATERIAL, WORKMANSHIP, AND TITLE: Purchaser is warranted that all
products manufactured 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 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 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. The Manufacturer 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.
102
8. Alarm Contact Maintenance
MI 611-169 – January 2021
103
MI 611-169 – January 2021
ISSUE DATES
FEB 1993
JAN 1996
APR 1997
JUN 2004
JUL 2005
FEB 2016
FEB 2017
JAN 2021
Vertical lines to the right of text or illustrations indicate areas changed at last issue date.
Schneider Electric Systems USA, Inc.
70 Mechanic Street
Foxboro, MA 02035
United States of America
http://www.se.com
Copyright 1993-2021 Schneider Electric Systems
Global Customer Support
USA, Inc. All rights reserved.
Inside U.S.: 1-866-746-6477
Outside U.S.: 1-508-549-2424
https://pasupport.schneider-electric.com The Schneider Electric brand and any trademarks of
Schneider Electric SE or its subsidiaries are the
property of Schneider Electric SE or its subsidiaries.
All other trademarks are the property of their
respective owners.
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