Schneider Electric 873DPX Dual pH/ORP/ISE Electrochemical Analyzers Style C Instruction Sheet

Instruction
MI 611-190
January 2021
873DPX Dual pH/ORP/ISE
Electrochemical Analyzer
Style C
MI 611-190 – January 2021
2
Contents
Figures ........................................................................................................................................... 7
Tables ............................................................................................................................................ 9
1. Introduction ............................................................................................................................ 11
Description ...............................................................................................................................11
Instrument Features ..................................................................................................................12
Enclosure..............................................................................................................................12
Dual Alarms .........................................................................................................................12
No Battery Backup Required................................................................................................12
Instrument Security Code ....................................................................................................12
Hazardous Area Classification ..............................................................................................13
Front Panel Display ..............................................................................................................13
Front Panel Keypad ..............................................................................................................13
Application Flexibility ..........................................................................................................14
Storm Door Option .............................................................................................................14
Analyzer Identification ..............................................................................................................14
Model Code ..............................................................................................................................15
Standard Specifications..............................................................................................................16
Electrical Safety Specifications ..................................................................................................17
2. Installation .............................................................................................................................. 19
Mounting to a Panel (873DPX-xxWxxx) ..................................................................................19
Mounting to a Pipe (873DPX-xxYxxx) .....................................................................................20
Mounting to a Surface — Fixed Mount (873DPX-xxXxxx).......................................................22
Mounting to a Surface — Movable Mount (873DPX-xxZxxx)..................................................24
Wiring Connections..................................................................................................................26
Foxboro Sensors with Integral Preamplifiers
(871PH, 871A-2) ..................................................................................................................27
Foxboro Sensors without Preamplifiers (871A-1 or 222F) .........................................................29
Sensors of Other Companies .....................................................................................................31
3. Operation ................................................................................................................................ 33
Overview...................................................................................................................................33
Display......................................................................................................................................33
Keypad......................................................................................................................................33
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MI 611-190 – January 2021
Contents
Mode ........................................................................................................................................35
Temp Key..................................................................................................................................36
View Setup Entries....................................................................................................................36
4. Configuration.......................................................................................................................... 37
Overview..................................................................................................................................37
Configure Mode........................................................................................................................37
Security Code............................................................................................................................38
Unlocking Analyzer Using Security Code .................................................................................38
Locking Analyzer Using Security Code.....................................................................................38
Configuration Setup Entries......................................................................................................38
Changing Setup Parameters..................................................................................................40
Configuration of Display and Damping (CELL) ..................................................................40
Holding the Analog Outputs and Alarms (Hold)..................................................................41
Alarm Configuration (AC1 and AC2) ..................................................................................42
Setting Alarm Level(s) .........................................................................................................44
Alarm 1 Configuration ....................................................................................................44
Alarm 1 Timers (Att1, AFt1, AdL1).................................................................................45
Alarm 2 Configuration ....................................................................................................49
Alarm 2 Timers (Att2, AFt2, AdL2).................................................................................49
Assignment of Analog Outputs (AOUt) ...............................................................................49
Scaling of Analog Outputs (H01, L01, H02, L02) ...............................................................50
Analog Output 1 — 100% Value (H01) .........................................................................50
Analog Output 1 — 0% Value (L01) ..............................................................................50
Analog Output 2 — 100% Value (H02) .........................................................................51
Analog Output 2 — 0% Value (L02) ..............................................................................51
User-Defined Measurement Error Upper Limit Value, CELL 1 or CELL 2 (UL1, UL2) ......51
User-Defined Measurement Error Lower Limit Value, CELL 1 or CELL 2 (LL1, LL2) ........52
User-Defined Temperature Error Upper Limit Value, Both Cells (UtL).....................................52
User-Defined Temperature Error Lower Limit Value, Both Cells (LtL).................................53
Basic Setup Entries ....................................................................................................................53
Unlocking Basic Setup Entries (bL) ......................................................................................54
Selecting and Changing the Full Scale Range (FSC1 and FSC2) ..........................................55
Temperature Compensation (CO1 and CO2) ......................................................................56
pH Compensation Selection (Digits 1 and 2) ..................................................................56
ISE Compensation Selection (Digits 3 and 4)..................................................................57
Isopotential Points (ISO1 and ISO2)....................................................................................58
Offset Voltage (OF)..............................................................................................................59
Log of Function (PF)............................................................................................................59
Acid Compensation .........................................................................................................59
Base Compensation .........................................................................................................59
4
Contents
MI 611-190 – January 2021
Selectivity Coefficient Compensation ..............................................................................59
User Entered pH (UPH) ......................................................................................................60
Temperature Cell Factors (tCF1, tCF2)................................................................................60
RTD Temperature Calibration (tCL1, tCC1, tCH1, tCL2, tCC2, tCH2) ...........................60
Changing the Analog Output...............................................................................................61
To Reposition Jumpers ....................................................................................................61
Analog Output Calibration (LCO1, HCO1, LCO2, HCO2) ..............................................63
Generating and Entering Custom Curves in the 873DPX ....................................................64
Custom Temperature Compensation Curve (tCt) ............................................................64
Custom PPM Curve (PCt) ...................................................................................................66
Timeout Time Adjustment ...................................................................................................69
Instrument Lock Code Change Control (LCC)....................................................................69
5. Calibration .............................................................................................................................. 71
Electronic Bench Calibration ....................................................................................................71
Equipment Required for Calibration ....................................................................................72
Procedure .............................................................................................................................72
Calibration Of A Sensor............................................................................................................75
General Information.............................................................................................................75
One and Two Point Calibration ................................................................................................76
Grab Sample Standardization ....................................................................................................77
Temperature Cell Factor............................................................................................................78
Determining tCF..................................................................................................................79
Entering a tCF Value ............................................................................................................79
6. Diagnostics .............................................................................................................................. 81
Troubleshooting ........................................................................................................................81
Using the 873 Analyzer to Troubleshoot a Sensor Problem ...................................................81
873 Error Codes/Actions .................................................................................................81
Additional Troubleshooting.......................................................................................................83
Error Codes...............................................................................................................................85
7. Alarm Contact Maintenance.................................................................................................... 87
5
MI 611-190 – January 2021
6
Contents
Figures
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
Front Panel Keypad and Display .........................................................................................13
Typical Data Label .............................................................................................................14
Mounting to a Panel ...........................................................................................................19
Mounting to a Pipe (Horizontal or Vertical)........................................................................21
Mounting to a Surface, Fixed Mount ..................................................................................23
Mounting to a Surface — Movable Mount .........................................................................25
Wiring Diagram for Foxboro Sensors with Preamplifiers ....................................................28
Rear Panel (Instrument) Wiring for Foxboro Sensors without Preamplifiers ........................30
Rear Panel (Instrument) Wiring for Sensors of Other Companies (without Preamplifiers) .32
Model 873DPX Keypad and Display ................................................................................34
Relationships Between Alarm Timers ..................................................................................46
Flow Diagram for Alarm Timer Logic .................................................................................48
Jumpers for Changing Analog Outputs ...............................................................................62
Flow Chart for Custom Temperature Compensation Curve ................................................64
Example of pH vs. Temperature Custom Curve ..................................................................66
Flow Chart for Custom Percent Concentration ...................................................................66
Custom ppm Data ..............................................................................................................68
Flow Chart for Electronic Bench Calibration ......................................................................71
Fluoride Electrode Response as Function of Temperature ....................................................74
Flow Chart for pH/ORP/ISE Sensor Calibration ................................................................76
Flow Chart for Single Point Calibration .............................................................................76
Flow Chart for Two Point Calibration ................................................................................76
Flow Chart for Grab Sample Calibration.............................................................................77
Relationship between pH and mV at Different Temperatures
for a Standard Glass pH Sensor and Ag/AgCl Reference Electrode ................................84
Alarm Contact Reconditioning Circuit ...............................................................................87
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MI 611-190 – January 2021
8
Figures
Tables
1
2
3
4
5
6
7
Recommended Conduit and Fitting
(Due to Internal Size Constraints).................................................................................32
Keypad Functions ...............................................................................................................34
Configuration Setup Entries................................................................................................39
Basic Setup Entries ..............................................................................................................53
mV Supply Formulas...........................................................................................................73
Temperature vs. Resistance Table for Pt 100 RTD...............................................................82
Error/Alarm Messages .........................................................................................................85
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MI 611-190 – January 2021
10
Tables
1. Introduction
Description
The 873DPX Dual pH/ORP/ISE Analyzer is an addition to the 873 family of electrochemical
analyzers that extends capabilities to ion-specific measurements as well as pH and ORP. The
873DPX analyzer interprets the pH/ORP or specific ion concentration of aqueous solutions and
displays measurement values in pH, mV, or ppm of the selected ion. It also measures solution
temperatures for both cells, which may be displayed on demand, for automatic temperature
compensation of pH and ISE (ion selective electrode) measurements.
The 873DPX can make dual (similar or different) measurements in a single solution. It can also
make dual (similar or different) measurements in different solutions if the difference in potential
between solutions does not exceed 5 V dc or 3.5 V ac. This capability allows for:
♦ Dual pH measurement
♦ Dual ORP measurement
♦ Dual ISE measurement
♦ Simultaneous pH and ORP measurement
♦ Simultaneous pH and ISE measurement
♦ Simultaneous ORP and ISE measurement
♦ pH corrected ISE measurement
The analyzer can accept inputs from two independent process measurement sensors (pH, ORP, or
ion-specific) plus RTD temperature detectors for both sensors. The unit can also output two
isolated analog signals proportional to any of the following:
♦ Measured values of both sensors
♦ Solution temperatures for both sensors
♦ Average of measured values for both sensors
♦ Ratio of measured values (Cell 1/Cell 2)
♦ Difference between measured values of both sensors (Cell 1 − Cell 2)
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MI 611-190 – January 2021
1. Introduction
Instrument Features
Some of the features of the 873DPX Analyzer are:
♦ Metal Field Enclosure
♦ Dual Alarms
♦ Dual Analog Outputs
♦ EEPROM Memory
♦ Instrument Security Code
♦ Hazardous Area Classification
♦ Front Panel Display
♦ Application Flexibility
♦ Storm Door Option
Enclosure
The metal enclosure is designed for field or control room locations and may be panel, pipe, or
surface mounted. It is constructed of cast 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-66. The unit fits in a
92 x 92 mm (3.6 x 3.6 in) panel cutout (1/4 DIN size). The enclosure also provides inherent
protection against radio frequency interference (RFI) and electro-magnetic 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 current measurement value on
the LED (light-emitting diode) display.
!
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 87.
No Battery Backup Required
Non-volatile EEPROM memory is used to protect all operating parameters and calibration
data in the event of a power interruption.
Instrument Security Code
A combination code lock method, user configurable, provides protection of operational
parameters from accidental or unauthorized access.
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1. Introduction
MI 611-190 – January 2021
Hazardous Area Classification
The instrument is designed to meet Class I, Division 2, Groups A, B, C, and D hazardous
locations.
Front Panel Display
The instrument display consists of a 4-digit bank of red LEDs, as shown on the next page.
The 14.2 mm (0.56 in) display height provides visibility at a distance up to 6 m (20 ft)
through a red-tinted, nonreflective, 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
after the last key is pressed. This feature is called “timing out.” The “timeout” time may be
adjusted to any time between 3 and 99 seconds. You can prevent the “timeout” from
occurring by pressing and holding the SHIFT key.
If no fault or alarm conditions are detected in the instrument, the measurement value is
displayed steadily. If, however, fault or alarm conditions do occur, the display alternately
shows the measurement and a fault or alarm message on a 1-second cycle.
Front Panel Keypad
The front panel keypad consists of eight keys. Some keys handle specific fixed functions;
others perform split functions. You can select the upper function (green legend) of a fixed
function key by pressing and holding the shift key as you press the split function key.
Figure 1. Front Panel Keypad and Display
ANALYZER TYPE
ANALYZER MODEL
MEASUREMENT VALUE
DISPLAY (4-DIGITS PLUS
DECIMAL POINT)
DUAL FUNCTION KEY
(PRESS/HOLD SHIFT AND
KEY FOR TOP FUNCTION.
PRESS KEY ONLY FOR
LOWER FUNCTION)
pH/ORP/ISE
873 DualAnalyzer
MEASUREMENT
LEGEND UNITS
DISPLAY
8.8.8.8.
Alt Cel
Cal Hi
mV
Temp
Alm 1
Next
Cal Lo
Setup
Alm 2
Lock
Shift
mV
Cel2
pH
ppm
Slope
SINGLE FUNCTION KEY
(PRESS KEY ONLY)
Enter
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MI 611-190 – January 2021
1. Introduction
Application Flexibility
The 873DPX Analyzer offers application flexibility through its standard software package.
The software, which runs on the internal microprocessor, allows you to define and set
operating parameters specific to your application. Such parameters fall into four general
categories:
1. Measurement Range
2. Alarm Configuration
3. Diagnostics
4. Output Characterization
These parameters are stored in EEPROM nonvolatile memory and are maintained in the
event of a power interruption.
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 mounted applications.
The transparent door, hinged for easy access to front panel controls, permits a clear view of
the display when closed.
Analyzer Identification
A data label, fastened to the side of the enclosure, provides model number and other information
pertinent to the specific instrument. An example is shown in the figure below.
Figure 2. Typical Data Label
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1. Introduction
MI 611-190 – January 2021
Model Code
Dual pH/ORP/ISE Electrochemical Analyzer
873DPX
Supply Voltage and Frequency
120 V ac, 50/60 Hz
-A
220 V ac, 50/60 Hz
-B
240 V ac, 50/60 Hz
-C
24 V ac, 50/60 Hz
-E
100 V ac, 50/60 Hz
-J
Measurement Output
0 to 20 mA dc, isolated
E
4 to 20 mA dc, isolated
I
0 to 10 V dc, isolated
T
Enclosure
Field, Metal, Panel Mounting
W
Field, Metal, Surface Mounting — Fixed
X
Field, Metal, Pipe Mounting
Y
Field, Metal, Surface Mounting — Movable
Z
Electrical Certification (see Product Safety Specifications Section)
CSA, Ordinary Locations (except 220 and 240 V ac options)
CGZ
FM, Ordinary Locations
FGZ
FM, Nonincendive, Division 2 Locations
FNZ
CSA, Nonincendive, Division 2 Locations (except 220 and 240 V ac options) (a)
CNZ
Optional Selections
Storm Door
-7
Special per Engineering Order
-0
(a) Not available at time of printing.
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MI 611-190 – January 2021
1. Introduction
Standard Specifications
Supply Voltages
-A
-B
-C
-E
-J
120 V ac
220 V ac
240 V ac
24 V ac
100 V ac
Supply Frequency
50 or 60 Hz, ±3 Hz
Output Signals
I:
T:
E:
Ambient Temperature Limits
-25 to +55°C (-13 to +131°F)
Measurement Ranges
pH:
ORP:
ISE:
Temperature Measurement Range
-17 to +199 °C (0 to 390°F)
Temperature Compensation Range
-5 to +105 °C (23 to 221°F)
4 to 20 mA isolated
1 to 10 V dc isolated
0 to 20 mA isolated
-2 to +16 pH
-999 to +1400 mV
300 mV span with range limits of -999
and +1000 mV (displayed as ppm)
Relative Humidity Limits
5 to 95%, noncondensing
Accuracy of Analyzer Display
±0.1% of upper range limit
Accuracy of Analyzer Outputs
±0.25% of upper range limit
Analyzer Identification
Refer to Figure 2.
Dimensions
96(H) x 96(W) x 259(L) mm
Enclosure Mounting Options
-W:
-X:
-Y:
-Z:
Approximate Mass
Metal Field Enclosure (with brackets)
Panel Mounting
1.28 kg (3.9 lb)
Pipe Mounting
2.54 kg (5.6 lb)
Fixed Surface Mounting
2. 46 kg (5.4 lb)
Movable Surface Mounting 3.38 kg (7.4 lb)
Instrument Response
2 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
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 chemical
feed, then delay for chemical concentration control.
Alarm Contacts
Two independent, nonpowered Form C contacts. Rated 5 A
noninductive, 125 V ac/30 V dc (minimum current 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 87.
Alarm Indication
Alarm status alternately displayed with measurement on LED display.
16
Metal Field Mount/Panel Mount
Metal Field Mount/Surface Mount
Metal Field Mount/Pipe Mount
Metal Field Mount/Movable Surface Mount
1. Introduction
MI 611-190 – January 2021
RFI Susceptibility
10 V/m from 27 MHz to 1000 MHz, when all sensor and power cables
are enclosed in a grounded conduit.
Electromagnetic Compatibility (EMC)
The Model 873DPX Electrochemical Analyzer, 220 V ac, or 240 V ac
systems with Metal Enclosure, comply 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 plastic case units comply with the European EMC Directive
89/336/EEC when mounted in a solid metal enclosure and the I/O
cables extending outside the enclosure are enclosed in solid metal
conduit. See Figure 1.
Electrical Safety Specifications
Testing Laboratory,
Types of Protection, and
Area Classification
Application Conditions
Electrical Safety
Design Code
FM for use in general purpose (ordinary) locations.
FGZ
FM nonincendive for use in Class I, Division 2, Groups Temperature Class T6.
A, B, C, and D; and suitable for Class II, Division 2,
Groups F and G, hazardous locations.
FNZ
CSA (Canada): for use in general purpose (ordinary)
locations.
CGZ
CSA (Canada): Suitable for use in Class I, Division 2,
Groups A, B, C, and D.
24 V, 100 V, and 120 V ac (Supply
option -A, -E, -J) only.
CNZ
NOTE
The analyzer has been designed to meet the electrical classifications listed in the table
above. For detailed information on the status of agency approvals, contact Global
Customer Support.
!
CAUTION
1. When replacing covers on the 873DPX case, use Loctite (Part No. S0106ML) on
the threads of screws for the front cover and Lubriplate (Part No. X0114AT) on the
threads of screws for the rear cover. Do not mix.
2. Exposure to some chemicals may degrade the sealing properties of Polybutylene
Teraethalate and Epoxy Schneider Electric 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.
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MI 611-190 – January 2021
18
1. Introduction
2. Installation
Mounting to a Panel (873DPX-xxWxxx)
The metal field-mounted 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. Remove rear bezel and insert analyzer through panel cutout. Temporarily hold in
place.
4. From rear of panel, slide plastic clamp onto enclosure until clamp latches (2) snap into
two opposing slots on longitudinal edges of enclosure. See Figure 3.
5. Tighten screws (CW) on clamp latches until enclosure is secured to panel.
6. Reassemble rear bezel to enclosure using the four captive screws.
Figure 3. Mounting to a Panel
PLASTIC CLAMP
CLAMP LATCH
REMOVABLE REAR BEZEL
PANEL THICKNESS NOT
TO EXCEED 20 mm (0.8 in)
PLASTIC CLAMP
SLOTS IN
LONGITUDINAL
EDGES OF
ENCLOSURE
CLAMP LATCH SCREW (2)
CLAMP LATCH (2)
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MI 611-190 – January 2021
2. Installation
Mounting to a Pipe (873DPX-xxYxxx)
1. Locate horizontal or vertical DN 50 or 2-inch pipe.
2. Assemble universal mounting bracket 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 with 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 and secure analyzer.
4. Lift entire assembly of Step 3 and, secure mounting bracket to pipe, using two Uclamps, nuts and washers.
20
2. Installation
MI 611-190 – January 2021
Figure 4. Mounting to a Pipe (Horizontal or Vertical)
MOUNTING
BRACKET
SUPPORT
STRAP
BRACKET
CLAMP
VERTICAL DN50 OR
MOUNTING
0.312-18 NUTS
2-INCH PIPE
BRACKET
(4 PLACES)
0.190-32
SCREWS (2)
U-CLAMP (2)
NOMINAL DN50 OR
2-INCH PIPE. HORIZONTAL PIPE SHOWN.
STRAP
PIVOT BOLT; MOUNTED ENCLOSURE
CLAMP
CAN BE ROTATED UP TO 60-DEGREES
IN VERTICAL PLANE
TWO U-CLAMPS ARE
USED TO SECURE
BRACKET TO PIPE.
12 13
1
6
6
13
7
11
2
3
5
4
10
9
8
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MI 611-190 – January 2021
2. Installation
Mounting to a Surface — Fixed Mount
(873DPX-xxXxxx)
1. Locate mounting surface for analyzer.
2. Referring to Figure 5, use mounting bracket as template for drilling four holes into
mounting surface. Notice that holes in the 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 and secure analyzer.
5. Lift entire assembly of Step 4, align mounting bracket holes with mounting surface
holes and use four user-supplied bolts, nuts, and washers to attach mounting bracket
to surface.
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2. Installation
MI 611-190 – January 2021
Figure 5. Mounting to a Surface, Fixed Mount
SURFACE (REFERENCE)
STRAP
SPACER
CLAMP
MOUNTING
0.190-32
BRACKET
SCREWS (2)
USER
SUPPLIED
STRAP
CLAMP
PIVOT BOLT (MOUNTED
SUPPORT
BRACKET
ENCLOSURE CAN BE
ROTATED UP TO 60-DEGREES
IN VERTICAL PLANE)
12
6
7
1
11
2
3
5
4
10
9
8
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MI 611-190 – January 2021
2. Installation
Mounting to a Surface — Movable Mount
(873DPX-xxZxxx)
1. Locate surface on which to mount the analyzer. Also refer to PL 611-016.
2. Referring to Figure 6, use wall bracket (12) as a template for drilling four holes into
mounting surface. Note 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 user-supplied bolts, washers, and nuts.
4. Assemble universal mounting as follows:
a. Insert 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 91) 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 and 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. Lock in
place using screw and washer.
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2. Installation
MI 611-190 – January 2021
Figure 6. Mounting to a Surface — Movable Mount
PIVOT BOLT (0.250-20) FOR
HORIZONTAL PLANE ROTATION
WALL BRACKET
SUPPORT
BRACKET
STRAP CLAMP
LOCK MOUNTING BRACKET
IN PLACE WITH 0.190-32
SCREW AND WASHER
PIVOT BOLT
SUPPORT BRACKET
FOUR BOLTS
(USER-SUPPLIED)
STRAP CLAMP
SPACER
PIVOT BOLT (0.312-18)
FOR VERTICAL PLANE
ROTATION
13
8
12
NYLON WASHER
AND NUT
0.190-32 SCREWS (2)
MOUNTING
BRACKET
10
10
9
8
14
16
15
9
10
1
11
2
3
5
4
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MI 611-190 – January 2021
2. Installation
Wiring Connections
Wiring installation must comply with any existing local regulations.
NOTE
To maintain a rating (NEMA 4X, CSA Enclosure 4X, or IEC Degree of Protection
IP-66), conduits with the proper fitting must be used (see Table 1 on page 32). Alarm
wires should run through the same conduit as the power wires. Sensor wires should
run through the same conduit as analog output wires.
The 873DPX Analyzer is equipped with a rear cover terminal board to facilitate sensor wiring.
The rear cover terminal strips are connected by a ribbon cable to the terminal blocks inside the
analyzer. Wiring can be installed by removing the rear cover for the 873 and making sensor
connections outside of the analyzer housing.
NOTE
The rear cover terminal strip may only be used with preamplified (or low impedance)
sensors such as the 871PH or the 871A-2. The 871A-1, the 222F, or any sensors of
other companies without a preamplifier (high impedance) may NOT be connected to
this terminal board unless a remote preamplifier is used (Part No.PS290AA or
PS290AB). Otherwise, non-preamplified sensors must be wired directly to the
terminal strips inside the analyzer. It is recommended that the remote terminal board
be removed from the rear cover if it is not in use. First, disconnect the ribbon cable
from the terminal blocks and then unscrew terminal board on rear cover and remove.
!
26
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 87.
2. Installation
MI 611-190 – January 2021
Foxboro Sensors with Integral Preamplifiers
(871PH, 871A-2)
Use the following procedure to connect Foxboro sensors with preamplifiers to terminal blocks on
the Rear Cover Terminal Board and the Instrument Terminal Board (see Figure 7):
1. Remove back cover to provide access to rear cover terminal board.
2. Route sensor wires through conduit openings at bottom of case.
3. On the Instrument Terminal Board, connect Alarm 1 and Alarm 2 wires to TB3, as
shown in the diagram. Failsafe operation requires that connections be made between
contacts NC and C, and that the alarms be configured active.
4. On the Instrument Terminal Board, connect wires for analog outputs to TB4 as
shown in the diagram.
5. On the Rear Cover Terminal Board, connect signal wires from Sensor 1 to the
terminal block marked Cell 1 as shown in the diagram.
6. On the Rear Cover Terminal Board, connect signal wires from Sensor 2 to the
terminal block marked Cell 2 as shown in the diagram.
7. On the Instrument Terminal Board, connect power wires to terminal block TB1, as
shown in the diagram. The earth (ground) connection from the power cord should be
connected to the ground stud located on the bottom of the enclosure.
NOTE
To obtain pH correction when measuring pH and ion-selective activity
simultaneously, the pH sensor MUST be connected to Cell 1.
27
MI 611-190 – January 2021
2. Installation
Figure 7. Wiring Diagram for Foxboro Sensors with Preamplifiers
871PH
OR 871A-2
871PH
OR 871A-2
REAR COVER
TERMINAL BOARD
1 BK
CELL 2
BK 1
RTD
1
2
3
3A
4
5
6
RTD
2 WH
7
WH 2
3 RD
RD 3
1
SENSOR 2
2
3
CELL 1
3A
4
5
6
4 GRN (SOL. GND)
7
(SOL. GND) CLR 4
5 ORANGE
CLR 5
6 BRN +
+BRN 6
POWER TO PREAMP
SENSOR 1
7 BLU
GROUND LUG
(-)
POWER TO
PREAMP
(-)BLU 7
NOTE: 3-A TERMINALS NOT USED.
PRIOR TO JUNE 2016
RIBBON CABLE
TO INSTRUMENT
TERMINAL BOARD
RIBBON CABLE-TO-TERMINAL
BOARD WIRE CONNECTION
Terminal
No.
TB2:
1
2
3
3A
4
5
6
7
TB5:
1
2
3
3A
4
5
6
7
Cable
Color
gray
violet
blue
green
yellow
orange
red
brown
OUTPUT 2
OUTPUT 1
INSTRUMENT
TERMINAL
BOARD
TB4
TB2
1 2 3 3A 4 5 6 7
blue/white
green/white
yellow/white
orange/white
red/white
brown/white
black
white
POWER
TB5
1 2 3 3A 4 5 6 7
TB1
TB3
L2 L1
NC C NONCC NO
HI
LO
EARTH
TO GROUND LUG
ON CASE
28
2- 2+ 1- 1+
ALARM 2
ALARM 1
(a)
AFTER JUNE 2016
RIBBON CABLE-TO-TERMINAL
BOARD WIRE CONNECTION(a)
Terminal
No.
TB2/Cell 1:
1
2
3
3A
4
5
6
7
TB5/Cell 2:
1
2
3
3A
4
5
6
7
Cable
Color
gray
violet
blue
green
yellow
orange
red
brown
gray
violet
blue
green
yellow
orange
red
brown
Two cable labels, TB2/Cell 1 and
TB5/Cell 2, are now installed on the
ribbon cable.
2. Installation
MI 611-190 – January 2021
Foxboro Sensors without Preamplifiers (871A-1 or
222F)
Use the following procedure to connect Foxboro sensors without preamplifiers to terminal blocks
on the Instrument Terminal Board (see Figure 8):
1. Remove back cover to provide access to rear cover terminal board. (Do not connect
anything to the Rear Cover Terminal Board.)
2. Remove all ribbon cable connections from the Instrument Terminal Board terminal
blocks. It is recommended that the rear cover terminal board be unscrewed and
removed from the rear cover.
3. Route sensor wires through conduit opening at bottom of case.
4. On the Instrument Terminal Board, connect Alarm 1 and Alarm 2 wires to TB3, as
shown in the diagram. Failsafe operation requires that connections be made between
contacts NC and C, and that the alarms be configured active.
5. On the Instrument Terminal Board, connect wires for analog outputs to TB4 as
shown in Figure 8.
6. On the Instrument Terminal Board, connect signal wires from Sensor 1 to terminal
block TB2 as shown in Figure 8.
7. On the Instrument Terminal Board, connect signal wires from Sensor 2 to terminal
block TB5 as shown in Figure 8.
8. On the Instrument Terminal Board, connect power wires to terminal block TB1, as
shown in Figure 8. The earth (ground) connection from the power cord should be
connected to the ground stud located on the bottom of the enclosure.
29
MI 611-190 – January 2021
2. Installation
OUTPUT 1
OUTPUT 2
SOL.GND
REFERENCE
871A-1
RD
GN
CLR(COAX)SHIELD
SENSOR 1
WH
BK
WH(COAX)SHIELD
WH(COAX)MEAS
RTD
Figure 8. Rear Panel (Instrument) Wiring for Foxboro Sensors without Preamplifiers
TB4
TB2
2- 2+ 1- 1+
1 2 3 3A 4 5 6 7
SENSOR 2
TB5
(SAME WIRING
AS SENSOR 1)
1 2 3 3A 4 5 6 7
TB1
POWER
TB3
L2 L1
NC C NONCC NO
HI
LO
TO GROUND LUG
ALARM 2
EARTH
ALARM 1
#3 REF.
RD,
OUTPUT 1
OUTPUT 2
#6 SOL.GND
GN,
SCRN (SHIELD) #2
BRN,(COAX) #1 MEAS
SENSOR 1
BK #4
WH #5
RTD
ON CASE
222F
TB4
TB2
1 2 3 3A 4 5 6 7
30
2- 2+ 1- 1+
2. Installation
MI 611-190 – January 2021
Sensors of Other Companies
Use the following procedure to connect sensors of other companies without preamplifiers to
terminal blocks on the Instrument Terminal Board:
1. Remove back cover to provide access to rear cover terminal board. (Do not connect
anything to the Rear Cover Terminal Board.)
2. Remove all ribbon cable connections from the Instrument Terminal Board terminal
blocks. It is recommended that the rear cover terminal board be unscrewed and
removed from the rear cover.
3. Route sensor wires through conduit opening at bottom of case.
4. On the Instrument Terminal Board, connect Alarm 1 and Alarm 2 wires to TB3, as
shown in Figure 9. Failsafe operation requires that connections be made between
contacts NC and C, and that the alarms be configured active.
5. On the Instrument Terminal Board, connect wires for analog outputs to TB4 as
shown in Figure 9.
6. On the Instrument Terminal Board, connect signal wires from Sensor 1 and its RTD
to the terminal block TB2 as shown in Figure 9.
7. On the Instrument Terminal Board, connect signal wires from Sensor 2 and its RTD
to the terminal block TB5 as shown in Figure 9.
8. On the Instrument Terminal Board, connect power wires to terminal block TB1, as
shown in Figure 9. The earth (ground) connection from the power cord should be
connected to the ground stud located on the bottom of the enclosure.
31
MI 611-190 – January 2021
2. Installation
REFERENCE
OUTPUT 2
OUTPUT 1
(NOTE 2)
SOL.GND
(NOTE 1)
MEAS
RTD (NOTE 3)
Figure 9. Rear Panel (Instrument) Wiring for Sensors of Other Companies (without Preamplifiers)
TB2
SENSOR 1
1 2 3 3A 4 5 6 7
SENSOR 2
(SAME WIRING
2- 2+ 1- 1+
TB4
AS SENSOR 1)
1 2 3 3A 4 5 6 7
TB5
TB1
POWER
NOTES
1.TO PREVENT SIGNAL DEGRADATION,
CABLE LENGTH MUST BE CONSIDERED.
2.SOLUTION GROUND MUST BE WIRED TO A
METALLIC MATERIAL IN CONTACT WITH THE
PROCESS SOLUTION.
3.USER-SUPPLIED 100-OHM PLATINUM RTD
(DIN 43760).
TB3
L2 L1
NC C NONCC NO
HI
LO
TO GROUND LUG
ALARM 2
EARTH
ALARM 1
ON CASE
Table 1. Recommended Conduit and Fitting
(Due to Internal Size Constraints)
Conduit
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
32
Fitting
3. Operation
Overview
The 873DPX functions in either of two modes, OPERATE or CONFIGURE (Setup). In the
OPERATE mode, the instrument automatically displays a measurement (or temperature) value
and outputs two analog signals proportional to two user-selected measurement or temperature
values. In the OPERATE mode, you can display the solution temperature or any parameter
setting. In the CONFIGURE mode, you can enter and/or modify any previously entered
parameter. All 873 analyzers are shipped configured with either factory default settings or userdefined parameters, as specified by the sales order. To use either mode, you must understand the
functions of the keypad and the display.
Display
The instrument display, as shown in Figure 10, consists of two parts: (1) a
measurement/parameter settings display, and (2) a backlit display of measurement units. The
measurement value may be displayed as any one of following:
♦ pH — expressed in pH units
♦ ORP — expressed in mV
♦ ISE — expressed in ppm
♦ Temperature — expressed in ºC or ºF
♦ Average of Sensors 1 and 2 — expressed in pH, mV or ppm
♦ Difference of Sensors 1 and 2 — expressed in pH, mV or ppm
♦ Ratio of Sensors 1 and 2 — expressed as a %
If you want to change from one display to another or to display anything other than the selections
listed above, you must use various keypad functions, as described in the next section. You may
also configure the display to toggle between Sensor 1 and Sensor 2 measurement value.
Keypad
The keypad, shown in , consists of eight keys, six of which are dual function. The white lettered
keys represent normal functions and the green lettered keys represent alternate functions To
operate a white lettered function key, just press the key. To operate a green lettered function key,
press/hold the SHIFT key and then press the function key. The notation used to describe this
operation is SHIFT + (key). All key functions are described in Table 2 on page 34.
33
MI 611-190 – January 2021
3. Operation
Figure 10. Model 873DPX Keypad and Display
pH/ORP/ISE
873 DualAnalyzer
8.8.8.8.
Alt Cel
Temp
Shift
Cal Hi
mV
Alm 1
Next
Cal Lo
Setup
Alm 2
Lock
mV
Cel2
pH
ppm
Slope
Enter
Table 2. Keypad Functions
Key
Function
Press and hold this key to actuate the green dual-function keys. Holding the SHIFT key after
pressing any function key delays the 10-second timeout, allowing you to view the display as long as
you hold the key.
Shift
Press this key to display a value or code for a setup entry. You can also use this key to execute an
action or selection or to store a value into memory.
Enter
Alt Cel
Temp
Cal Hi
ALT CEL: Press/hold SHIFT and press this key to display the measurement value of the alternate
cell.
TEMP: Press this key to display current solution temperature in C or F. If a dot is displayed following
the C or F, the value displayed is a manual entry of temperature that overrides the actual measured
value for temperature compensation.
CAL HI: Press/hold SHIFT and press this key to access the upper calibration function of the
analyzer.
ALM 1: Press this key to display and/or change the set point of Alarm 1.
Alm 1
34
3. Operation
MI 611-190 – January 2021
Table 2. Keypad Functions (Continued)
Key
Function
Cal Lo
CAL LO: Press/hold SHIFT and press this key to access the lower calibration function of the
analyzer.
ALM 2: Press this key to display and/or change the set point of Alarm 2.
Alm 2
mV
mV: Press/hold SHIFT and press this key to display the measurement value in absolute millivolts.
NEXT: Press this key to select a digit or setup entry.
Next
Setup
SETUP: Press/hold SHIFT and press this key to access the configuration entry function.
LOCK: Press this key to display and/or change the security lock state of the instrument.
Lock
Slope
SLOPE: Press/hold SHIFT and press this key to display the calibration slope value in millivolts/pH or
millivolts/ppm decade.
INCREMENT: Press this key to increase the display count by one. Press and hold to increase count
at a rate of approximately one per second.
NOTE
Pressing NEXT and INCREMENT 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. Pressing and holding SHIFT and ENTER
simultaneously overrides the 10-second wait between Setup entries.
Mode
When you turn power on, the 873DPX analyzer runs in the OPERATE mode. The instrument
first conducts a self-diagnostic test and then automatically displays the selected display value (see
CELL code description, Chapter 4).
While in the Operate Mode, you may display the measurement, the solution temperature, and all
parameter settings as configured in the Configuration Setup Entries and Basic Setup Entries
described in Chapter 4
35
MI 611-190 – January 2021
3. Operation
Temp Key
To view the process temperature, push TEMP. The display then changes from the current display
to the solution temperature (or manually entered override value) for the primary sensor.
The display consists of a rounded whole number plus the temperature units (ºC or ºF). The units
display alternately switches between ºC (or ºF) and the tenths of degrees measurement value.
Once the TEMP key has been pressed, the INCREMENT (Δ) key toggles the temperature
between ºC and ºF, and also allows you to activate manual temperature compensation. Pushing Δ
while in the TEMP mode causes the display to sequence from the current value through a series of
displays similar to that shown in the following example:
(1)
(2)
(3)
(4)
77.F
or
77.0
77.F.
or
77.0
25.C
or
25.0
25.C.
or
25.0
When a decimal point after the C or F is present, this indicates that the process temperature is
compensated manually at the temperature displayed, thus overriding the automatic temperature
compensation function (i.e., manual temperature compensation is active). If you want to use
another manual compensation temperature value, press NEXT + Δ repeatedly to change the
display to the desired temperature and then press ENTER. The process will then be compensated
for the new displayed temperature value. To return to automatic compensation, sequence the
display (using the Δ button) to remove the decimal point after C or F. Note, however, that you
cannot adjust automatic temperature compensation by this procedure. To adjust temperature in
the automatic mode, refer to Chapter 5
When dual sensors are used, you can display the process temperature (or manually adjusted
temperature) of the alternate sensor by pressing and holding NEXT before pressing the TEMP
key. The Cel2 legend is then illuminated and the process temperature (or manually adjusted
temperature) for the alternate sensor appears on the display. Note that you cannot adjust the
temperature of the alternate sensor via this procedure.
View Setup Entries
You may display Setup Entries at any time. To view any of the Setup Entries, follow the
procedures given in “Configuration Setup Entries” on page 38 or “Basic Setup Entries” on
page 53, but do not UNLOCK the instrument.
When viewing Setup Entries, you may page through the parameters as rapidly as you wish by
pressing SHIFT + SETUP and then pressing NEXT one or more times. However, once you have
pressed ENTER to read a parameter value (value is displayed for 10 seconds), you must wait 10
seconds for the parameter symbol to reappear. The parameter symbols appear for 10 seconds also.
If you do not press another key within 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. The time
out time may be adjusted to any value between 3 and 99 seconds by using the tOut parameter. To
make changes to any Configuration Setup Parameter, see the section on “Configuration” on
page 37.
36
4. Configuration
Overview
This instrument is shipped with either factory settings (default values) or user-defined settings, as
specified in the sales order. Table 3, “Configuration Setup Entries,” on page 39 lists all the
parameters that are frequently changed. Table 4, “Basic Setup Entries,” on page 53 lists
parameters that are calibration oriented. Both tables list the parameter identifier symbol, the
name of the parameter, and a space for you to write your own values.
The configuration process consists of entering and/or modifying parameters to make the Analyzer
function to your particular needs. This chapter explains how to enter and change specific items
via the keypad. Because reconfiguration may also involve wiring or jumper changes, you must be
sure that you check all such items before placing the Analyzer into service either on startup or
following a parameter change of any kind.
You enter all parameters as 4-digit numerical codes, selecting the code from tables specific to each
parameter. For parameters that are entered as direct 4-digit values, however, no table is supplied.
The configuration process consists of four simple steps:
1. Write down all your parameter settings in the spaces provided in the configuration
tables.
2. Unlock the instrument.
3. Select the parameter entry identifier on the display and enter the 4-digit codes.
4. Lock the instrument.
Configure Mode
The Configure Mode is protected through two levels of security, one for Configuration Setup
Entries and another for Basic Setup Entries. Note that every configuration change starts with
unlocking the instrument, which is accomplished by entering a security code at the keypad.
37
MI 611-190 – January 2021
4. Configuration
Security Code
The Analyzer uses two levels of security. The first level protects against unauthorized change of
the parameters Temp, Alm 1, Alm 2, Cal Lo, Cal Hi, and all the Configuration Setup Entries. The
second level protects against the remaining setup entries, called Basic Setup Entries. There are 32
such parameters.
Note that any of the parameters discussed above can be viewed (but not changed) when the
Analyzer is in the locked state. When displaying a parameter in the locked state, the digits do not
flicker. Any attempt to change the parameter while in this mode causes the message Loc to appear
on the display.
You use the same security code to unlock the unit in both levels of security. When the unit is
unlocked at the first level (see Unlocking Analyzer Using Security Code), the unit remains unlocked
until you take a positive action to lock the unit again (see Locking Analyzer Using Security Code).
However, when the unit is unlocked using the bL entry at the second level of security (see Basic
Setup Lock Control), it remains unlocked only as long as you access any one of the Basic Setup
Entries. As soon as the Analyzer defaults to the current measurement value (i.e., “times out”), the
second level of security automatically locks again. You must execute an unlock procedure,
therefore, to reaccess Basic Setup Entries.
Unlocking Analyzer Using Security Code
The procedure for unlocking the Analyzer is:
1. Press LOCK. Display will read Loc.
2. Press NEXT and then press NEXT + INCREMENT (Δ) repeatedly until the security
code is displayed (factory set at 0800).
3. Press ENTER. Analyzer will then read uLoc, indicating that it is now in the unlocked
state.
Locking Analyzer Using Security Code
The procedure for locking the Analyzer is:
1. Press LOCK. Display will read uLoc.
2. Press NEXT and then press the NEXT + INCREMENT (Δ) keys repeatedly until the
security code is displayed (set at 0800 by factory).
3. Press ENTER. Analyzer will then read Loc, indicating that it is now in the locked
state.
Configuration Setup Entries
Configuration setup entries consist of 21 parameters. Because these parameters are process
oriented, access to them is passcode protected. Table 3 lists each parameter (entry identifier) in
the same sequence as seen on the display, the name of the parameter, and a space for recording
your particular setting. A detailed description of each parameter is given in the explanatory text
following the table.
38
4. Configuration
MI 611-190 – January 2021
Table 3. Configuration Setup Entries
Parameter
Identifier
Parameter/Value Accessed
Factory
Default
Values
CELL
Configuration of Display and Damping
1000
Hold
Hold and sets the Analog value in Hold
0000
AC 1
Alarm 1 Configuration
Measurement Alarm Assignment
Low/High/Instrument plus passive/active state
Hysteresis
1403
Att1*
Alarm 1 Trigger Time
00.00
AFt1*
Alarm 1 Feed Time
00.00
AdL1*
Alarm 1 Delay Time
00.00
AC 2
Alarm 2 Configuration
Measurement Selection
Low/High/Instrument plus passive/active state
Hysteresis
1203
Att2**
Alarm 2 Trigger Time
00.00
AFt2**
Alarm 2 Feed Time
00.00
AdL2**
Alarm 2 Delay Time
00.00
AOUt
Assignment of Analog Outputs
12.00
H0 1***
100% Analog Output - Output 1
14.00
L0 1***
0% Analog Output - Output 1
00.00
H0 2***
100% Analog Output - Output 2
14.00
L0 2
0% Analog Output - Output 2
00.00
UL 1
User-Defined Upper Measurement Error - Cell 1
14.00
LL 1
User-Defined Lower Measurement Error - Cell 1
00.00
UL 2
User-Defined Upper Measurement Error - Cell 2
14.00
LL 2
User-Defined Lower Measurement Error - Cell 2
00.00
Ut L
User-Defined Upper Measurement Error - Both Cells
100.0
Lt L
User-Defined Lower Temperature Error -Both Cells
000.0
User
Settings
* Not displayed if disabled via AC1 parameter.
** Not displayed if disabled via AC2 parameter.
*** Not displayed if disabled via AOUt parameter.
39
MI 611-190 – January 2021
4. Configuration
Changing Setup Parameters
To change any of the Configuration Setup parameters listed in the table above, use the following
procedure:
1. Unlock Analyzer.
2. Press SHIFT + SETUP. Release both keys.
3. Press NEXT one or more times until the parameter you want to change is displayed.
4. Press ENTER. The 4-digit code for that parameter then appears.
5. Press/hold NEXT to select the digit you wish to change and press INCREMENT (Δ)
to change the digit. Repeat until the desired code or value is displayed.
6. Press ENTER.
7. Lock Analyzer.
NOTE
You should set the configuration setup parameters whenever you make any changes to
FSC.
Configuration of Display and Damping (CELL)
The CELL parameter determines the type of measurement to be displayed on the Analyzer front
panel and the amount of damping applied to the measurement.
The Display Assignment Digit (Digit 1) selects the measurement (or calculated ratio, difference,
or average) value to be displayed. In addition, if Digit 1 is set to 0, the display alternates between
measurement values of Sensors 1 and 2.
The Dual Cell Configuration Digit (Digit 2) should be set to 0 if operating in dual sensor mode
and to 1 in single sensor mode. “0” means normal dual cell operation. “1” means that if a cell is
not configured on both alarms, the output and display modes of that cell are ignored. If both cells
are configured (ratio is displayed), neither cell is ignored, regardless of the setting of Digit 2.
The Damping Selection Digits (Digits 3 and 4) select the amount of damping applied to each
sensor (Digit 3 for Sensor 1 and Digit 4 for Sensor 2). Damping time refers to an interval over
which all measurement values are averaged. Damping also affects temperature displays and analog
outputs.
40
4. Configuration
MI 611-190 – January 2021
CELL Configuration Codes
Digit 1
Digit 2
Digit 3
Digit 4
Display Assignment
Dual Cell Configuration
Damping Cell 1
Damping Cell 2
0
Toggle Cell 1 and 2
Measurement
0
Dual Cell
Operation
0
No Damping
0
No Damping
1
Cell 1 Measurement
1
Single Cell
Operation
1
10 Seconds
1
10 Seconds
Digit
Not
Used
2
Cell 2 Measurement
2
3
Temperature Cell 1
3
2
20 Seconds
2
20 Seconds
3
40 Seconds
3
40 Seconds
4
Temperature Cell 2
4
5
Digit Not Used
5
4
5
Digit
Not
Used
4
Digit
Not
Used
6
Average Cell 1 and Cell 2
Measurement
6
6
7
Ratio
(Cell 1/Cell 2) x 100
7
7
5
6
7
8
Digit Not Used
8
8
8
9
Difference (Cell 1 - Cell 2)
9
9
9
Holding the Analog Outputs and Alarms (Hold)
This parameter sets the HOLD characteristics for both analog outputs.
When HOLD is activated, the analog outputs freeze at particular values determined by the setting
of this parameter. The various codes are shown in the table below.
To use this feature, unlock the Analyzer, press SETUP, and then press NEXT repeatedly until the
identifier HOLD is displayed. Set Digit 1 to the value that holds alarms to the value you want,
and then set Digits 2, 3, and 4 to the percentage of full scale at which you want the analog output
to freeze. Then press ENTER to execute your selection.
When HOLD is activated and the first digit of this code is 1, 2, or 3, the display alternately
flashes between the word HOLD and the VALUE measured by the currently selected sensor. The
output is frozen at a value corresponding to a percentage of full scale of the analog output. This
percentage is determined by the last three digits of the HOLD code. While in any of the HOLD
modes, the Analyzer continues to monitor and display the measurement value. Note that while in
this mode, you may clean or replace the sensor and recalibrate the system. As shown in the table
below, alarms are held in a fixed state (current, ON, or OFF) whenever Hold is activated. The
specific state is determined by the setup code you enter.
41
MI 611-190 – January 2021
4. Configuration
HOLD Configuration Codes
Digit 1
Output Hold
0
No Hold
1
Hold — Alarms Held in
Current State
2
Hold — Alarms Held in OFF
State
3
Hold — Alarms Held in ON
State
4
Digit
Not
Used
5
6
Digit 2
Digit 3
Digit 4
Percentage of Analog Output Range
0 to 100%
7
8
9
NOTE
Trying to enter a digit with no assigned function will result in the code Err.
Alarm Configuration (AC1 and AC2)
Two independent, Form C dry alarm contacts, rated at 3A noninductive, 125 V ac/30 V dc are
provided with the Analyzer. They are designated as Alarm 1 and Alarm 2.
!
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 87.
Setting the parameter, AC1, configures Alarm 1 — assigning it to monitor the measurement
output of Cell 1 or Cell 2, the average of both cell measurements, the ratio of Cell 1 to Cell 2
measurements, or the difference between the two measurements. The second digit of the code
determines whether the alarm output is high or low, active or passive, instrument active or passive,
and hold active or passive. The third and fourth digits of the code set the hysteresis of the alarm
output, the deadband between set and reset values of alarm activation.
When an alarm condition exists, the display alternately shows alarm status and measurement
value, alternating on a 1-second cycle. Wiring information for the alarms may be found in
Chapter 2 of this manual.
NOTE
1. You must reset alarms following any change to FSC because the alarms are set as a
percentage of FSC.
2. When power is applied to the instrument, alarm operation is delayed for a time
period proportional to the damping time set in CELL1 (Digit 3) or CELL2
(Digit 4). Alarms will remain OFF until the measurement has stabilized.
42
4. Configuration
MI 611-190 – January 2021
When used as a measurement alarm, four configurations are possible:
1. Low passive
2. Low active
3. High passive
4. High active
A low alarm trips on decreasing measurement. A high alarm trips on increasing measurement.
Passive or active (failsafe) configurations are selected by setting Digit 2. When configured as a
passive alarm, power is not applied to the relay coil when the alarm is OFF. With an active alarm,
however, power is applied to the relay coil when the alarm is OFF, thus providing failsafe
operation. In the active (failsafe) configuration, loss of power to the Analyzer causes 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. (Refer to Chapter 2)
As an alternative to a measurement alarm, one or both alarms may be set up as instrument alarms.
In this “watchdog” state, the alarm can communicate the existence of any diagnostic error in the
system. When used as a diagnostic alarm, however, the alarm cannot also be used as a
conventional measurement alarm.
When an alarm is configured as a diagnostic error communicator, it will report any system
problem. It cannot, however, selectively report a specific type of problem. The hardware/software
conditions that can cause a diagnostic (instrument) alarm are:
1. A/D converter error
2. EEPROM checksum error
3. RAM error
4. ROM error
5. Processor task time error (watchdog timer)
In addition to these diagnostics, you may program several temperature and measurement error
limits that, if exceeded, will cause an alarm condition. Refer to Table 7, “Error/Alarm Messages,”
on page 85 for a list of error messages and their meanings.
The alarm may also be configured and used as a HOLD alarm. When used as a HOLD alarm, the
alarm cannot be used as a conventional measurement alarm. When so configured, the alarm will
trigger whenever HOLD is activated. By using this feature, you can notify a control room or
alarm device (light, bell, etc.) that the Analyzer is in a HOLD mode instead of a RUN mode. The
ALARM is activated when HOLD is implemented if 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.
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4. Configuration
Setting Alarm Level(s)
NOTE
This procedure is relevant only when the alarms have been configured as measurement
high or measurement low alarms. When the alarms are configured as Instrument
(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 Alm 1. Then use NEXT to select the digit and Δ to set the
desired value for the digit.
3. When you have set all digits, press ENTER.
4. To set Alarm 2, press Alm 2. Then use NEXT to select the digit and Δ to set the
desired value for the digit.
5. When you have set all digits, press ENTER.
6. Lock Analyzer (see “Locking Analyzer Using Security Code” on page 38).
NOTE
If use of the alarms is not desired, set Digit 1 of AC1 or AC2 to 0.
Alarm 1 Configuration
AC1 Configuration Codes
Digit 1
Digit 2
Alarm Selection
Configuration
0
Alarm Not Used (Disables Errors
and Parameters, Relay Held
OFF/Passive)
0
Digit Not Used
1
Measurement Cell 1
1
Low/Passive
2
Measurement Cell 2
2
Low/Active
3
Temperature Cell 1
3
High/Passive
4
Temperature Cell 2
4
High/Active
5
Digit Not Used
5
Instrument/Passive
6
Average Cell 1 and Cell 2
Measurement
6
Instrument/Active
7
Ratio (Cell 1/Cell 2) x 100
7
Hold/Passive
8
Digit Not Used
8
Hold/Active
9
Difference (Cell 1 - Cell 2)
9
Digit Not Used
Digit 3
Digit 4
Hysteresis
0 to 99% of full scale
NOTE
When Digit 1 of AC1 is set to 0 (i.e., alarm not used), all error messages associated
with the alarm are disabled and timer configuration codes (Att1, AFt1, and Adl1) do
not appear when stepping through the setup entries.
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4. Configuration
MI 611-190 – January 2021
Alarm 1 Timers (Att1, AFt1, AdL1)
Three timers are associated with Alarm 1:
♦ Att1 — Alarm 1 Trigger Time
A programmable timer that prevents the alarm from triggering for a user-defined
time.
♦ AFt1 — Alarm 1 Feed Time
A programmable timer that holds the alarm ON for a user-defined time once the
alarm has been activated — to allow time for chemical/reagent feed.
♦ AdL1 — Alarm 1 Delay Time
A programmable timer that holds the alarm OFF for a user-defined time after the
alarm has been held ON by parameter AFt to allow time for mixing or reaction.
Each of these timers is explained in detail in this section. Note, however, that whenever you use
any of these timers, the hysteresis function set in parameter AC1 is ignored.
Alarm 1 Trigger Time (Att1) may be used with or without the other alarm timers. Att1 is used only
when Alarm 1 is configured as a measurement alarm (high/low) or temperature (high/low). Its
purpose is to prevent the alarm from triggering on momentary, non-sustained off-normal
conditions. After the timer has timed out, the alarm will activate if the measurement has sustained
an off-normal state for the entire trigger time. If the measurement returns to normal at any time,
Att1 resets automatically. The table below defines the configuration codes for Att1.
Att1, AFt1, and AdL1 Configuration Codes
Digits 1 and 3
00 to 99 minutes
Digit 3
0 to 9 tenths of minutes
Digit 4
0 to 9 hundredths of minutes
EXAMPLES:
05.15 means 5 minutes, 9 seconds — 5 minutes + 1 /10 of a minute
(6 seconds) + 5/100ths of a minute (3 seconds)
20.50 means 20 minutes, 30 seconds — 20 minutes +5/10 of a minute
(30 seconds)
Alarm 1 Feed Time (AFt1) and Alarm 1 Delay Time (AdL1) may be used whenever Alarm 1 is
configured as a measurement or temperature alarm. Alarm Feed Time (AFt1) works in
conjunction with Alarm Delay Time (AdL1) to provide one cycle of pulse-duration on/off control
of the Alarm 1 relay (although AFt1 may be used without AdL1). Therefore, these parameters
should be set and used together. Note that both take precedence over the hysteresis deadband set
in parameter AC1.
When Alarm 1 Feed Time is activated, Alarm 1 remains ON for the length of time set in AFt1
regardless of what the measurement value is — inside or outside of normal range.
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4. Configuration
Alarm 1 Delay Time (AdL1) is activated by entering a value in parameter AdL1. Upon timeout of
AFt1, the alarm is held OFF for this time period. The alarm will not reactivate for the time period
set in AdL1 regardless of what the measurement value is. After timeout of AdL1, the 873 reverts
to normal run mode. If the instrument has remained in an alarm state for the entire time period
(AFt1 + AdL1), the sequence of AFt1 followed by AdL1 repeats for another cycle without having
to wait another Att1 period (see Figure 12), and so on, until the measurement returns to normal
range and reset the alarm.
The relationships between Att1, AFt1, and AdL1 are illustrated in the following diagram, where
Alarm 1 is configured as a high alarm.
Figure 11. Relationships Between Alarm Timers
a
i
h
SetPoint
b
Measurement
ON
f
c
a
i
Alarm Relay
b
OFF
ON
d
h
OFF
Att1 (5 min.)
a
ON
e
OFF
AFt1 (15 min)
ON
e
OFF
AdL1 (15 min)
0
10
20
30
40
MINUTES
46
50
60
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4. Configuration
MI 611-190 – January 2021
NOTES:
a. Measurement did not remain above set point for timer period set in Att1. Alarm
relay remains inactive. Att1 reset when measurement fell below alarm set point.
b. Measurement stays above alarm setpoint continuously for time set by Att1(5
min). After time set in Att1, alarm relay becomes activated (c) for time period (15
min) set by parameter AFt1.
c. Timer Att1 reset when measurement fell below set point (d).
d. Upon timeout of AFt1, timer AdL1 deactivates Alarm 1 relay (f ) for the time
period set by this parameter. The alarm remains deactivated even if measurement
(g) exceeds the alarm set point during this period of time.
e. Since the measurement exceeds the set point at the end of AdL1, the timer Att1
resets and the alarm relay remains OFF. If the measurement does not exceed the
alarm set point for the entire period Att1 (i), the alarm relay does not activate. If
the measurement had exceeded the set point for the entire sum of times (AFt1 +
AdL1), the feed timer (AFt1) would have been reactivated.
A flow diagram for alarm timer logic follows. Note that the flow diagram and the timing diagram
apply to both alarms (AC1 and AC2).
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4. Configuration
Figure 12. Flow Diagram for Alarm Timer Logic
Start
Measurement
N
Measurement
exceed
alarm set point?
Y
Att1
N
Meas.
above set point
continuously for
time Att1?
Y
AFt1
AdL1
Did meas.
exceed set point
continuously for time
AFt1 + AdL1?
N
48
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4. Configuration
MI 611-190 – January 2021
Alarm 2 Configuration
Alarm 2 is configured in exactly the same manner as Alarm 1. Refer to AC1 setup instructions.
AC2 Configuration Codes
Digit 1
Digit 2
Alarm Selection
Configuration
0
Alarm Not Used
(Disables Errors and
Parameters, Relay Held
OFF/Passive)
0
Digit Not Used
1
Measurement Cell 1
1
Low/Passive
2
Measurement Cell 2
2
Low/Active
3
Temperature Cell 1
3
High/Passive
4
Temperature Cell
4
High/Active
5
Digit not Used
5
Instrument/Passive
6
Average Cell 1 and Cell 2
Measurement
6
Instrument/Active
7
Ratio
(Cell 1/Cell 2) x 100
7
Hold/Passive
8
Digit not used
8
Hold/Active
9
Difference
(Cell 1 - Cell 2)
9
Digit Not Used
Digit 3
Digit 4
Hysteresis
0 to 99% of full scale
NOTE
When Digit 1 of AC2 is set to 0 (i.e., alarm not used), all error messages associated
with the alarm are disabled and timer configuration codes Att2, AFt2, and AdL2 do
not appear when stepping through the setup entries.
Alarm 2 Timers (Att2, AFt2, AdL2)
Alarm 2 timers operate in the same manner as Alarm 1 timers. Refer to Alarm 1 timers setup
instructions.
Assignment of Analog Outputs (AOUt)
The AOUt parameter defines analog output assignments. Each output signal is linearly
proportional to the assigned measurement value (or calculated value such as ratio, average, or
difference). Either output may be disabled by setting the appropriate digit to 0. If set to 0, the
output is held at 4 mA (or 0 V), all error messages associated with that output are disabled, and
the 0% (L01 or L02) and 100% (H01 or H02) configuration codes do not appear in the setup
menu. Digit 4 enables or disables local display of an analog error code.
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4. Configuration
AOUt Configuration Codes
Digit 1
Output 1 Assignment
Digit 2
Output 2 Assignment
Digit 4
Analog Error Enable
Digit 3
0
Output Disabled, output held 0
at 4 mA or 0 V, no error
message.
Output Disabled, output held
at 4 mA or 0 V, no error
message.
0
Enabled
1
Measurement Cell 1
1
Measurement Cell 1
1
Disabled
2
Measurement Cell 2
2
Measurement Cell 2
3
Temperature Cell 1
3
Temperature Cell 1
4
Temperature Cell 2
4
Temperature Cell 2
5
Digit Not Used
5
Digit Not Used
6
Average of Cell 1 and Cell 2
Measurements
6
Average of Cell 1 and Cell 2
Measurements
7
Ratio
(Cell 1/Cell 2)
x 100
7
Ratio
(Cell 1/Cell 2)
x 100
8
Digit Not Used
8
Digit Not Used
9
Difference
(Cell 1 - Cell 2)
9
Difference
(Cell 1 - Cell 2)
Digit Not Used
Not Used
NOTE
The analog outputs may swing between the minimum and maximum values
immediately after power up, a power interruption, or a reset of the microprocessor.
Scaling of Analog Outputs (H01, L01, H02, L02)
These parameters are used in conjunction with the AOUt code and will not appear in the setup
menu when the output assignment is zero.
Both analog outputs may be scaled so as to improve the sensitivity of the analog output in the
range of interest. The maximum output span that should be set on the Analyzer is the FSC value.
The minimum span allowed is 10% of the FSC value. Although it is possible to set the Analyzer
for a smaller span, a loss of accuracy will result.
You may also wish to reverse the analog signal in some situations. The outputs may be scaled so
that the value in L01 (or L02) is higher than the value in H01 (or H02), if desired. No special
procedures are required to achieve a reverse acting output.
Analog Output 1 — 100% Value (H01)
This parameter sets the full scale value of Analog Output 1. The value set by this parameter
corresponds to 100% of the analog output (20 mA or 10 V).
Analog Output 1 — 0% Value (L01)
This parameter sets the zero scale value of Analog Output 1. The value set by this parameter
corresponds to 0% of the analog output (0 mA, 4 mA, or 0 V).
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4. Configuration
MI 611-190 – January 2021
Analog Output 2 — 100% Value (H02)
This parameter sets the full scale value of Analog Output 2. The value set by this parameter
corresponds to 100% of the analog output (20 mA or 10 V).
Analog Output 2 — 0% Value (L02)
This parameter sets the zero scale value of Analog Output 2. The value set by this parameter
corresponds to 0% of the analog output (0 mA, 4 mA, or 0 V).
User-Defined Measurement Error Upper Limit Value,
CELL 1 or CELL 2 (UL1, UL2)
These parameters enable you to define an upper measurement limit that, if exceeded, will give an
error message on the display (see “Table 7 on page 85). When used in conjunction with the
configurable alarms, it provides a relay contact output.
The primary use of UL1 or UL2 is as a sensor diagnostic tool. If a problem develops with a sensor
that causes the measurement signal to be ridiculously low or high for the process being monitored
(such as a shorted or intermittent connection), an alarm can be triggered. By setting UL1 or UL2
at a value that could never be achieved in a normal process situation, activation of a UL1 or UL2
alarm indicates a severe sensor failure, miscalibration, or a process out-of-control. The upper limit
on UL1 or UL2 is 99.99 pH or 9999 mV.
NOTE
UL1 and UL2 values equal to the specified full scale measurement per Sales Order are
preconfigured.
UL1 and UL2 Configuration Codes
Digit 1
Sign
0 to 9
Positive Value
–
Negative Value
Digit 2
Digit 3
Digit 4
Upper Limit Value
-0.99 to 99.99 for pH
-999 to 9999 for ORP and ISE
NOTE
To make a minus sign appear on the display for either upper limit value or lower limit
value, you must enter a digit other than zero.
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4. Configuration
User-Defined Measurement Error Lower Limit Value,
CELL 1 or CELL 2 (LL1, LL2)
These parameters are similar to the previously described UL parameters, except they allow
programming of a lower measurement limit. The lower limit on LL1 or LL2 is -0.99 pH or
-999 mV.
LL1 or LL2 Configuration Codes
Digit 1
Sign
Digit 2
Digit 3
Digit 4
Lower Limit Value
0 to 9
Positive Value
-0.99 to 99.99 for pH
-999 to 9999 for ORP and ISE
–
Negative Value
User-Defined Temperature Error Upper Limit Value,
Both Cells (UtL)
This parameter enables the user to define an upper temperature measurement value that, if
exceeded, will give an error message on the display (Table 7 on page 85). When used in
conjunction with the configurable high or low alarms, this parameter provides a relay contact
output.
The UtL function may be used in several ways. First, you may wish to alarm on high process
temperature. For example, in a pH measurement that is normally between 80 and 100 ºF, you
may wish to set UtL to 120 ºF to indicate a problem with the process temperature. Another use of
UtL is as a sensor diagnostic tool. If the RTD in the pH 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 pH sensor temperature transducer. The upper limit on UtL is 200ºC
or 392ºF.
UtL Configuration Codes
Digit 1
Digit 2
Upper Limit Value
<200ºC or 392ºF Upper Temperature Limit
52
Digit 3
Digit 4
4. Configuration
MI 611-190 – January 2021
User-Defined Temperature Error Lower Limit Value, Both
Cells (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 –20ºC or -5ºF.
LtL value is preconfigured to 0ºC.
NOTE
To make a minus sign appear on the display, you must enter a digit other than zero.
LtL Configuration Codes
Digit 1
Digit 2
Digit 3
Digit 4
Upper Limit Value
<0 ºC or -5 ºF Lower Temperature Limit
Basic Setup Entries
Basic Setup entries consist of 32 parameters. Because these parameters are calibration oriented,
access has two levels of passcode protection. Changes to many of these parameters require that you
recalibrate the Analyzer. Do not make any changes unless you have read the explanatory text for
each parameter.
The table below lists the basic setup parameter identifiers (in the order in which they appear on the
display) and the name of the parameter or value accessed by the identifier. Descriptions of how to
set each digit of the display for every parameter are presented in the explanatory text following the
table.
Table 4. Basic Setup Entries
Parameter
Identifier
Parameters and Value Accessed
Factory Default
Value
bL
Basic Setup Lock Control
FSC1
Full Scale Value Cell 1
16.00 pH
FSC2
Full Scale Value Cell 2
20.00 ppm
C0 1
Compensation Cell 1
0000
C0 2
Compensation Cell 2
2010
ISO1
Isopotential Cell 1
-0.01
ISO2
Isopotential Cell 2
0000
OF
Offset Voltage
00.00
PF
Log of Function
00.00
UPH
User-entered pH
-0.01
tCF1
Temperature Cell Factor - Cell 1
25.00
tCF2
Temperature Cell Factor - Cell 2
25.00
tCt
Custom Curve Temperature
0000
PCt
Custom Curve pH
0000
tCL1
RTD Low Temp. Electronics Calibration Cell 1
100.0
tCC1
RTD Mid Temp. Electronics Calibration Cell 1
150.0
tCH1
RTD High Temp. Electronics Calibration Cell 1
200.0
User Value
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4. Configuration
Table 4. Basic Setup Entries (Continued)
Parameter
Identifier
Parameters and Value Accessed
Factory Default
Value
tCL2
RTD Low Temp. Electronics Calibration Cell 2
100.0
tCC2
RTD Mid Temp. Electronics Calibration Cell 2
150.0
tCH2
RTD High Temp. Electronics Calibration Cell 2
200.0
LCO1
Analog Out 1 Calibration Low
00.00
HCO1
Analog Out 1 Calibration High
100.0
LCO2
Analog Out 2 Calibration Low
00.00
HCO2
Analog Out 2 Calibration High
100.0
PC*
Probe Calibration
0000
dCL*
Drive Calibration Low
N/A
dCH*
Drive Calibration High
N/A
tout
Timeout Time
0010
LCC
Lock Code Change
0800
SFt**
Software Version Number
SOH**
Sales Order High
SOL**
Sales Order Low
User Value
* These parameters are factory calibrated to appropriate values. Do not alter these parameters in the field.
** These parameters are factory preset for informational purposes only. They cannot be changed in the field.
Unlocking Basic Setup Entries (bL)
To change any of the Basic Setup Entries, use the following procedure.
1. Unlock Analyzer at the first security level (see “Unlocking Analyzer Using Security
Code” on page 38).
2. Press SHIFT + SETUP. Release both keys.
3. Press NEXT repeatedly until bL is displayed.
4. Press ENTER. LOC appears on the display.
5. Press NEXT.
6. Use NEXT and Δ until security code is displayed (0800 from factory).
7. Press ENTER. ULOC appears on the display.
8. When display returns to bL, press NEXT one or more times until parameter to be
changed appears on the display.
9. Press ENTER.
10. Use NEXT and Δ until the desired value is displayed.
11. Press ENTER.
12. When the display defaults (times out) to the current measurement value, the Analyzer
is automatically locked at the second level (bL) of security.
13. Lock Analyzer (see “Locking Analyzer Using Security Code” on page 38).
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4. Configuration
MI 611-190 – January 2021
bL Configuration Codes
Digit 1
Digit 2
Digit 3
Digit 4
Basic Setup Enable
4-digit LOCK # (enables changing of setup values for entries following a bL entry.
Basic Lock is reactivated automatically when SETUP is exited via a default timeout.)
Selecting and Changing the Full Scale Range (FSC1 and FSC2)
The FSC1 and FSC2 parameters permit you to select the mode of operation for each channel of
the 873DPX — pH, ORP, or one of several ISE ranges. The FSC range choices are listed in the
following table.
FSC1 and FSC2Configuration Codes
Digit 1
Digit 2
Digit 3
Digit 4
Units of Measurement
16.00 — pH
1400 — mV
2.000 — ppm
20.00 — ppm
200.0 — ppm
2000 — ppm
FSC1 is the full scale range for Sensor 1 and FSC2 is the full scale range for Sensor 2. You can use
any combination of FSC1 and FSC2 codes. Note, however, that pH-corrected ISE measurements
require that Sensor 1 be a pH sensor (i.e., FSC1 = 16.00 pH) and Sensor 2 be the appropriate ISE
(i.e., FSC2 = 2, 20, 200, or 2000 ppm).
NOTE
1. Altering the FSC range via the Keypad will require that you bench calibrate the
unit before use.
2. Pressing ENTER in FSC mode (even if range was not changed) will require the
unit to be bench calibrated before use. If the range is set at the FSC you require,
allow unit to time out. Do not press ENTER.
After changing FSC, Configuration Setup Entries should be checked and altered if necessary. The
the FSC value per Sales Order is preconfigured.
The procedure to change FSC is as follows:
1. Unlock Analyzer (see Unlocking Analyzer Using Security Code).
2. Press SHIFT + SETUP. Release both keys.
3. Press NEXT several times until the code bL (Basic Setup Lock) is displayed.
4. Press ENTER, then use NEXT and Δ until the personal security code is displayed
(0800 from factory).
5. Press ENTER.
6. When the display returns to bL, press NEXT. The code FSC1 (Full Scale Range
Change) will be displayed. If FSC2 is desired, press NEXT again.
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MI 611-190 – January 2021
4. Configuration
7. Press ENTER. The present full scale range will be displayed. If this is your desired
FSC, allow unit to time out. DO NOT PRESS ENTER. Entering any FSC at this
point will cause Er4 to flash on the display. A bench calibration then must be
performed.
8. Press Δ until the desired range is displayed.
9. Press ENTER.
10. Lock Analyzer (see Locking Analyzer Using Security Code).
NOTE
Calibration is required after full scale range is changed. Error code Er4 will flash until
calibration is accomplished. Refer to the Calibration section in Chapter 5
Temperature Compensation (CO1 and CO2)
CO1 and CO2 are used to select the type of temperature compensation to be applied to the
measurement. Temperature compensation is applied to pH and ISE measurements only and is not
available for ORP measurements. If FSC1 (or FSC2) is configured for ORP measurement, the
entries in C01 (or C02) are ignored. CO1 sets the compensation for Sensor 1 and CO2 set the
compensation for Sensor 2.
pH Compensation Selection (Digits 1 and 2)
Digit 1 is used for choosing the type of electrode — glass, antimony, or variable isopotential. If
glass or antimony is chosen (0 or 1), the isopotential point of the electrode is fixed at 7 pH for
glass and at 1 pH for antimony. You may vary the isopotential point by selecting 2 for this digit
and setting the ISO1 (or ISO2) configuration code to the desired isopotential. See the section
on“Isopotential Points (ISO1 and ISO2)” on page 58 for a more detailed discussion.
Digit 2 is used for choosing the type of temperature compensation applied to the measurement.
Choosing 0 applies the standard Nernstian compensation, which is appropriate for most pH
applications. With this type of compensation, the Analyzer uses the temperature reading from the
process (or a manually entered temperature) to adjust the Nernst slope factor and, hence, the pH
value. The pH displayed is the actual pH of the process at the temperature of measurement. This type
of temperature compensation adjusts for temperature effects on the electrodes, but does not
correct for the fact that the actual solution pH may vary with temperature. Choosing 1 not only
applies the standard Nernstian compensation, but also applies an additional correction for water
samples with 1 ppm ammonia. This correction provides a pH value referenced to 25ºC to
compensate for the variations of solution pH due to the presence of ammonia. Choosing 9 applies
a custom temperature compensation curve that corrects for temperature-related variations in
solution pH. Custom curves, which are application dependent, require you to determine and
enter process-specific pH versus temperature data. See Custom Temperature Compensation (tCt) for
details.
Digits 1 and 2 are ignored if the corresponding FSC is set to ORP or ISE.
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4. Configuration
MI 611-190 – January 2021
ISE Compensation Selection (Digits 3 and 4)
Digit 3 sets the ion polarity. If the ion to be measured is a positive ion (such as sodium,
potassium, calcium, or silver), Digit 3 should be set to zero. If it is a negative ion (such as fluoride,
chloride, cyanide, or bromide), Digit 3 should be set to 1.
Digit 4 is used to set the type of compensation applied to the measurement. As with pH, setting
the digit to 0 provides the standard Nernstian temperature compensation. Choosing 1, 2, or 3 in
CO2 only, allows you to correct the ISE measurement for acid, base, or selectivity coefficient
errors. For this type of correction, a pH sensor must be used as Sensor 1 and an ISE used for
Sensor 2. The 873DPX will use the pH reading from Sensor 1 to make the appropriate correction
on a ISE reading from Sensor 2. You must also enter the appropriate constant in the PF
configuration code (see “Log of Function (PF)” on page 59 for details.). If a pH sensor is not used
with the 873DPX, this type of correction can still be performed by using a manually entered
constant pH value in the UPH configuration code and selecting either a 4, 5, or 6 (for Manual
Acid, Base, or Selectivity Coefficient). The 873DPX performs these corrections using the UPH
value as the pH of the process. (Refer to “User Entered pH (UPH)” on page 60 for details.)
Finally, custom temperature and ppm curves may be used to compensate the ISE measurement by
selecting 7 (custom temperature and ppm curves), 8 (custom ppm only), or 9 (custom
temperature only). Refer to “Generating and Entering Custom Curves in the 873DPX” on
page 64 for details.
Digits 3 and 4 are ignored if the corresponding FSC is set to ORP or pH.
CO1 Configuration Codes
Digit 1
Digit 2
Digit 3
Digit 4
Electrode Type
pH Compensation
Ion Polarity
ISE Compensation
0
Glass (fixed isopotential =
pH 7)
0
1
Antimony (fixed isopotential 1
= pH 1)
2
ISE, variable potential
selected by ISO1
Standard Nernstian
Compensation
0
Positive Ion
0
Standard Nernstian
Compensation
Ammonia
1
Negative Ion
1
Not Used
2
2
2
3
3
3
3
4
4
5
5
6
6
7
4
Digits 2 - 8
Not Used
5
6
Digits 2-9
Not Used
4
Manual Acid
5
Manual Base
6
Manual Selectivity
Coefficient
7
7
7
Custom Temperature and
ppm Compensation
8
8
8
8
Custom ppm
Compensation Only
9
9
9
9
Custom Temperature
Compensation Only
Digits 3-9
Not Used
Custom Temperature
Compensation
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4. Configuration
CO2 Configuration Codes
Digit 1
Digit 2
Digit 3
Digit 4
Electrode Type
pH Compensation
Ion Polarity
ISE Compensation
0
Glass (fixed isopotential =
pH 7)
0
Standard Nernstian
Compensation
0
Positive Ion
0
Standard Nernstian
Compensation
1
Antimony (fixed
isopotential = pH 1)
1
Ammonia
1
Negative Ion
1
Acid
2
ISE, variable potential
selected by ISO2
2
Digits 2-8
Not Used
2
Digits 2-9
Not Used
2
Base
3
Digits 3-9
Not Used
3
3
3
Selectivity Coefficient
4
4
4
Manual Acid
5
5
5
5
Manual Base
6
6
6
6
Manual Selectivity
Coefficient
7
7
7
7
Custom Temperature and
ppm Compensation
8
8
8
8
Custom ppm
Compensation Only
9
9
9
9
Custom Temperature
Compensation Only
4
Custom Temperature
Compensation
Isopotential Points (ISO1 and ISO2)
These parameters set the isopotential point for Sensor 1 (ISO1) and Sensor 2 (ISO2). When the
corresponding FSC is configured for ISE measurement and CO1 and CO2 have been set to
variable isopotential, this code allows you to enter an isopotential point (a millivolt value that
reads the same at every temperature) of an ISE. This value is also called the isothermal point. The
code can be set anywhere between -999 and +1000 mV. Unless the isopotential point of an ISE is
known or has been experimentally determined, this value should be left at 0 mV. When the FSC
is configured for pH measurement, this code allows you to adjust the isopotential pH of the
sensor if CO1 (or CO2) is configured for a pH electrode with an adjustable isopotential.
ISO1 and ISO2 Configuration Codes
Digit 1
Isopotential Temperature Compensation
-999 to +1000 mV
-9.99 to 99.99 pH
58
Digit 2
Digit 3
Digit 4
4. Configuration
MI 611-190 – January 2021
Offset Voltage (OF)
The 873DPX configured for ISE measurement has a 300 mV span with range limits of -999 to
+1000 mV. This 300 mV span can be shifted anywhere the range. The offset voltage, set by the
OF parameter, determines where that span is to be centered. If, for example, you selected an OF
of 700, the 300 mV span of the instrument would be 550 to 850 mV. The default value of OF is
0 mV, providing a range of -150 mV to +150 mV.
OF Configuration Codes
Digit 1
Digit 2
Digit 3
Digit 4
Offset voltage to center 300 mV ISE range
-850 to +850 mV
Log of Function (PF)
This parameter is used for entering the constant needed for calculation of acid, base, and
selectivity coefficient compensation of ISE measurements.
Acid Compensation
Acid compensation is used when the ion to be measured can complex with hydrogen ions. For
example, fluoride ions in acidic solutions can complex with hydrogen ions to form HF or HF2.
These complexes will not be detected by the fluoride electrode. By measuring the pH of the
solution or by using a manually entered pH value in the UPH parameter, however, the 873DPX
can calculate the proportion of fluoride ions that are complexed with hydrogen, thus providing a
means for correcting this error. This calculation requires a constant (pKa) to be entered in the PF
parameter. You can obtain the pKa from standard literature or determine it experimentally
[pKa = -log(Ka)].
Base Compensation
Base compensation is used when the ion to be measured can complex with hydroxide ions and not
be detected by the ISE. As with acid correction, the 873DPX can compensate for this effect by
measuring solution pH or by using a manually entered pH value from the UPH parameter, and
then calculating the proportion of ions complexed with hydroxide. This calculation requires a
constant (pKb) to be entered in the PF parameter. You can obtain the pKb from standard
literature or determine it experimentally [pKb = -log(Kb) = -log(14 - Ka)].
Selectivity Coefficient Compensation
Selectivity coefficient compensation is used when an interfering ion can cause errors in an ISE
measurement. For example, a fluoride electrode is also sensitive to the presence of hydroxide ions.
In basic solutions, a fluoride sensor will react to hydroxide ions as well as fluoride ions, giving an
abnormally high reading. By measuring the pH of the solution or by using a manually entered pH
value from the UPH parameter, the 873DPX can compensate for the interfering effect of
hydroxide ions. This calculation requires a constant to be entered in the PF parameter. The PF
constant is determined experimentally.
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MI 611-190 – January 2021
4. Configuration
PF Configuration Codes
Digit 1
Digit 2
Digit 3
Digit 4
Constant for Compensation of ISE
00.00 to 99.99
User Entered pH (UPH)
This parameter is used with manual acid, base, or selectivity coefficient compensation of an ISE
measurement. Instead of correcting an ISE measurement for a pH value obtained from a pH
sensor, the 873DPX can use a manually entered pH value from this parameter. If you want to use
acid, base, or selectivity coefficient correction of an ISE measurement and you know the pH of
your process, you may enter it in this parameter and then select manual acid, manual base, or
manual selectivity coefficient compensation using CO1 or CO2. (See “Temperature
Compensation (CO1 and CO2)” on page 56 for details.) The 873DPX will perform the
appropriate correction using the UPH value instead of an actual pH measurement value.
NOTE
To use this parameter, the pH of the process must be known and must also remain
stable.
UPH Configuration Codes
Digit 1
Digit 2
Digit 3
Digit 4
User-entered pH
0000 to 16.00
Temperature Cell Factors (tCF1, tCF2)
These parameters set the temperature correction factors for Sensors 1 and 2. These factors are
used to compensate for extended cable length. Refer to “Temperature Cell Factor” on page 78 for
more detail.
RTD Temperature Calibration (tCL1, tCC1, tCH1, tCL2,
tCC2, tCH2)
RTD temperature electronics are factory calibrated to compensate for calibration errors caused by
thermal effects in the electronic equipment. This calibration aligns the electronics to the
theoretical temperature transducer values at 25ºC. 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.
60
4. Configuration
MI 611-190 – January 2021
For Sensor 1, use tCL1, tCC1, and tCH1. For Sensor 2, use tCL2, tCC2, and tCH2.
To perform this calibration, execute the following procedure:
1. Connect a 100-ohm precision resistor between sensor input terminals 1 and 2.
2. Unlock Analyzer using security code.
3. Press SHIFT + SETUP. Release both keys.
4. Press NEXT several times until the code bL (Basic Lock Setup) is displayed.
5. Press ENTER, and then use NEXT and Δ until the personal security code is
displayed (0800 from factory).
6. Press ENTER.
7. When display returns to bL, press NEXT until tCL1 (or tCL2) is displayed. Press
ENTER.
NOTE
Holding the SHIFT key will keep the display from timing out.
8. Display will show 100.0 ohms. Press SHIFT and hold for 20 seconds, then press
ENTER.
9. Repeat Steps 1 - 8 using tCC1 (or tCC2) and a 150-ohm precision resistor.
10. Repeat Steps 1 - 8 using tCH1 (or tCH2) and a 200-ohm precision resistor.
Changing the Analog Output
To change one or both of the analog outputs from those ordered with the Analyzer, you must
reposition jumpers and recalibrate the instrument.
To Reposition Jumpers
1. Remove power from the instrument.
2. Remove four front panel screws holding the display panel in place. Remove rear cover.
Disconnect the green earth (ground) cable and feed wire from the sensors and power
connection through seals to allow free movement of the circuit boards.
!
CAUTION
Since the four screws are self-tapping, they have a limited number of taps. Do not
remove and tighten these screws repeatedly.
3. To access the upper circuit board designated AS700DZ-02, slide the circuit assembly
out the front of the housing.
4. Refer to Figure 13 on page 62 to identify jumper locations.
5. Use the following table to determine appropriate jumper positions.
Output
J5
J7
J6
J10
4 - 20 mA
2-3
2-3
2-3
2-3
0 - 20 mA
2-3
2-3
2-3
2-3
0 - 10 V dc
1-2
1-2
1-2
1-2
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MI 611-190 – January 2021
4. Configuration
6. Move each jumper to the appropriate position.
7. Replace board assembly inside unit.
8. Replace cover. Use Loctite (Part No. S0106ML) and Lubriplate (Part No. X0114AT)
on threads of screws of all metal enclosures.
9. Perform an analog output calibration, using procedures described in the next section.
10. Make appropriate changes to the Analyzer identification label.
Figure 13. Jumpers for Changing Analog Outputs
J6
J10
1
2
3
1
2
3
1
2
3
J5
Output
4 -20 mA
0 - 20 mA
0 -10 Vdc
62
J5
J6
J7
J10
2-3
2-3
1-2
2-3
2-3
1-2
2-3
2-3
1-2
2-3
2-3
1-2
1
2
3
J7
NOTE: JUMPERS J6 AND J10
CORRESPOND TO ANALOG
OUTPUT #1. JUMPERS J5 AND
J7 CORRESPOND TO ANALOG
OUTPUT #2.
4. Configuration
MI 611-190 – January 2021
Analog Output Calibration (LCO1, HCO1, LCO2, HCO2)
These parameters set the minimum or maximum values of the analog outputs as a percentage of
full scale value (10.0 V or 20.0mA).
Since the instrument was calibrated at the factory, it should not require recalibration unless the
type of output has been changed. To calibrate Analog Output 1, execute the following procedure:
1. Connect an ammeter/voltmeter to the analog output terminals.
2. Unlock the Analyzer using the security code.
3. Press SHIFT + SETUP. Release both keys.
4. Press NEXT several times until the code bL is displayed. Press ENTER.
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)/ (Analog High) x 100
8. Use NEXT and Δ until the calculated value from Step 7 is displayed. When finished,
press ENTER.
NOTE
Iteration of the above procedure may be required. Repeat Steps 7 and 8 until
Observed Value is equal to the Desired Value.
9. When the display returns to LCO1, press NEXT once to display HCO1. Press
ENTER.
10. Calculate the high % input required, using the following formula:
% = [(Observed Reading/Desired Reading) ] x 100
11. Use NEXT and Δ until the calculated value from Step 10 is displayed. When
finished, press ENTER.
NOTE
Iteration of the above procedure may be required. Repeat Steps 10 and 11 until
Observed Value equals Desired Value.
12. To calibrate Analog Output 2, repeat the above procedure substituting LCO2 and
HCO2 for LCO1 and HCO1.
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MI 611-190 – January 2021
4. Configuration
Generating and Entering Custom Curves in the 873DPX
Custom temperature compensation and process-specific concentration data may be entered into
873DPX Analyzers via the Curve Generation Program. This section explains how to generate and
enter custom curve data into your 873DPX Analyzer. To use the data after entering it, you must
set up parameters CO1 and CO2.
Custom Temperature Compensation Curve (tCt)
Figure 14. Flow Chart for Custom Temperature Compensation Curve
Determine
custom
temperature
vs. pH (or
ppm) data
unlock
Cell 1
or 2
Temp
°C or °F
FSC
(units)
tCt
1. User-supplied process-specific compensation data must be generated or extracted
from literature in advance of entering it into the 873DPX. This data must consist of
temperature (ºF or ºC) vs. pH (or ppm) data for a particular concentration of the
process (control point suggested). The temperatures should include all temperatures
in the target process temperature range and be entered in ascending order. It is
suggested that you plot the data graphically in preparing it for entry into the
873DPX.
EXAMPLE:
The control point of a process is 10.0 pH. The process typically runs at ambient temperatures
that fall in the range of 0 to 50ºC. A sufficient grab sample of the process is taken and
protected from atmosphere. Using a pH (or ISE) sensor and the 873DPX Analyzer set for
standard Nernstian temperature compensation (CO1 or CO2 = 0000), pH vs. temperature
data is generated. The data results are shown in Figure 15.
2. The user-supplied, process-specific compensation data must be reduced to fewer than
25 pairs, using the following general guidelines:
a. Enter the data into the Analyzer with increasing values of temperature, using the
current temperature scale of the unit.
b. A maximum or minimum temperature difference between successive temperature
points is not required and the intervals do not have to be equally spaced.
It is suggested that in a linear region you choose two or three points and that in a
region where an exponential (curved) relationship exists, you use more data
points.
c. The maximum number of data pairs you may enter is 25.
3. The process-specific reference temperature must be determined.This is the optimum
temperature at which your process runs and is the temperature to which you wish all
values corrected. In the example, the reference temperature is 25ºC.
64
4. Configuration
MI 611-190 – January 2021
4. Access Setup Code tCt.
a. The first number to enter is the number of pairs of temperature/pH (or ppm) data
you wish to enter. Press ENTER.
b. The second number to enter is the reference temperature, using the temperature
units convention set in Step 2. No temperature units will be displayed. Press
ENTER.
c. The third number to enter is the first temperature value.
d. Use NEXT and Δ to display the corresponding pH (or ppm) value from your
table. The legend should display the correct units of measurement. (The legend
and decimal point display will show the units of the currently active probe
“FSC.”) Press ENTER.
e. Repeat Steps 4c and 4d in sequence. To avoid a timeout while you make the
entries, press and hold SHIFT. If a timeout does occur, however, you must restart
from Step 4a. However, as all data entered up to the timeout will remain, simply
step through the data points via ENTER until you reach the timeout point. The
continued example below illustrates the procedure.
EXAMPLE (continued from previous page):
Enter the following numbers into the tCt parameter in the sequence shown.
Item
Number of pairs
Reference Temperature
First Temperature
First pH (or ppm) value
Second temperature
Second pH (or ppm) value
Third temperature
Third pH (or ppm) value
Fourth temperature
Fourth pH (or ppm) value
Fifth temperature
Fifth pH (or ppm) value
Sixth temperature
Sixth pH (or ppm) value
Seventh temperature
Seventh pH (or ppm) value
Eighth temperature
Eighth pH (or ppm) value
Ninth temperature
Ninth pH (or ppm) value
Tenth temperature
Value Entered
11
25.0
0.0
10.32 pH
5.0
10.25 pH
10.0
10.18 pH
15.0
10.12 pH
20.0
10.06 pH
25.0
10.01 pH
30.0
9.97 pH
35.0
9.93 pH
40.0
9.89 pH
45.0
Action
Press ENTER.
Press ENTER.
Press ENTER.
Press ENTER.
Press ENTER.
Press ENTER.
Press ENTER.
Press ENTER.
Press ENTER.
Press ENTER.
Press ENTER.
Press ENTER.
Press ENTER.
Press ENTER.
Press ENTER.
Press ENTER.
Press ENTER.
Press ENTER.
Press ENTER.
Press ENTER.
Press ENTER.
65
MI 611-190 – January 2021
4. Configuration
Item
Value Entered
Action
9.86 pH
50.0
9.83 pH
Tenth pH (or ppm) value
Eleventh temperature
Eleventh pH (or ppm) value
Press ENTER.
Press ENTER.
Press ENTER.
5. This completes entry of custom temperature data. To use the information for
temperature correction of pH or ppm data, set up CO1 or CO2 to use custom
temperature compensation data.
Figure 15. Example of pH vs. Temperature Custom Curve
DATA DERIVED EXPERIMENTALLY
pH
OR FROM LITERATURE
pH
TEMP (°C)
10.4
10.32
10.25
10.18
10.12
10.06
10.01
9.97
9.93
9.89
9.86
9.83
0
5
10
15
20
25
30
35
40
45
50
10.3
10.2
10.1
10
pH READING AFTER TCT COMPENSATION
IS APPLIED
9.9
9.8
0
5
10
15
20
25
30
35
40
45
55
60
TEMPERATURE °C
Custom PPM Curve (PCt)
Figure 16. Flow Chart for Custom Percent Concentration
Determine
custom
ppm data
(Actual vs
observed)
66
unlock
Cell 1
or 2
FSC
(ppm)
CO1
or
CO2
PCt
4. Configuration
MI 611-190 – January 2021
1. User-supplied process ppm data must be generated before you enter it into the
873DPX Analyzer. The data must consist of actual ppm values versus observed ppm
values. The concentrations should include the entire range that the process may
experience. You must enter the actual ppm values in ascending order and not change
the direction of slope of the data. In preparing the data, it is helpful to plot the data as
a graph as well as a table.
EXAMPLE:
A series of solutions with known fluoride concentrations ranging from 0.3 ppm to 10 ppm are
prepared. Using a fluoride sensor and the 873DPX with standard Nernstian compensation
(CO1 or CO2 set to xx10), a set of observed ppm readings versus actual ppm concentrations
is collected. Results are shown in Figure 17, with ppm concentrations plotted against
millivolts. The graph is plotted on a semilogarithmic scale to illustrate the linear relationship
between mV and ppm decades. Note that in the range below 1 ppm actual ppm readings
deviate from an ideal linear response. Entering the observed ppm vs. actual ppm data into tCt
allows the 873DPX to correct this nonlinearity. The data results are shown in Figure 17.
2. The user-supplied ppm data must be reduced to 25 or fewer pairs, using the following
guidelines:
a. The data should be presented and entered into the Analyzer with increasing ppm
values.
b. The slope of the data must not change sign.
c. A maximum or minimum ppm difference between data points is not required and
the intervals between points do not have to be evenly spaced. In a linear region,
two or three points is sufficient. In a region where an exponential or curved
relationship exists, more data points should be entered.
d. The maximum number of data pairs is 25.
3. Custom temperature compensation tCt should be entered first. Refer to the preceding
section for details. Unlock bL. Press NEXT repeatedly until PCt appears on the
display. Then press ENTER.
a. First, enter the number of data pairs you plan to enter. Press ENTER.
b. Next, enter the first observed ppm value. Use NEXT and Δ to display the first
observed ppm value in your table. The display should show the ppm units legend.
Press ENTER.
c. Use NEXT and Δ to display the corresponding actual ppm value from your table.
Press ENTER. The Cel2 legend should be displayed.
d. Repeat Steps 3b and 3c in sequence. To avoid a timeout while entering data, press
and hold SHIFT. If a timeout does occur, however, restart the procedure from
Step 3a.
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MI 611-190 – January 2021
4. Configuration
Figure 17. Custom ppm Data
-30
ACTUAL PPM
-20
OBSERVED PPM
-10
mV
0.1
10
20
30
1.0
ppm
10.0
EXAMPLE:
Enter data into the PCt parameter in the following sequence:
Item
Number of pairs
Fist observed ppm reading
First actual ppm value
Second observed ppm reading
Second actual ppm value
Next observed ppm reading
Next actual ppm value
Next observed ppm reading
Next actual ppm value
Next observed ppm reading
Next actual ppm value
Next observed ppm reading
Next actual ppm value
Next observed ppm reading
Next actual ppm value
Final observed ppm reading
Final actual ppm value
68
Value Entered (legend)
8
0.1 (ppm)
0.03 (Cel2)
0.13(ppm)
0.05 (Cel2)
0.18 (ppm)
0.1 (Cel2)
0.29 (ppm)
0.2 (Cel2)
0.37 (ppm)
0.3 (Cel2)
0.77 (ppm)
0.7 (Cel2)
1 (ppm)
1 (Cel2)
10 (ppm)
10 (Cel2)
Action
Press ENTER.
Press ENTER.
Press ENTER.
Press ENTER.
Press ENTER.
Press ENTER.
Press ENTER.
Press ENTER.
Press ENTER.
Press ENTER.
Press ENTER.
Press ENTER.
Press ENTER.
Press ENTER.
Press ENTER.
Press ENTER.
Press ENTER.
4. Configuration
MI 611-190 – January 2021
4. This completes the custom ppm curve entry. To use this information for correcting
ppm concentration data, set up CO1 (or CO2) to correspond to xxx7 or xxx8. Refer
to “Temperature Compensation (CO1 and CO2)” on page 56 in this chapter.
Timeout Time Adjustment
When the 873DPX is in the SETUP mode and no key is pressed within a 10-second period, the
Analyzer automatically exits from SETUP and defaults to OPERATE mode. This feature is called
timing out. The timeout time is factory-set at 10 seconds. You may, however, change the time to
any value between 3 and 99 seconds by setting the tOut parameter.
tOut Configuration Code
Digit 1
Digit 2
Digit 3
Digit 4
Adjustable Timeout Time
3 to 99 seconds
Instrument Lock Code Change Control (LCC)
This parameter permits you to change the security code to another 4-digit code.
To enter a new code, execute the following procedure:
NOTE
If you have forgotten the existing security code, you must contact Global Customer
Support for instructions on how to enter a new one.
1. Leave power on.
2. Press LOCK. Display will show either Loc or uLoc.
3. If uLoc is displayed, proceed to Step 4.
4. If Loc is displayed, unlock the Analyzer. Display will read uLoc.
5. Press SHIFT + SETUP. Release both keys.
6. Press NEXT several times until the code bL (Basic Setup Lock) is displayed. Press
ENTER.
7. Then use NEXT and Δ until existing security code is displayed (0800 from factory).
8. Press ENTER.
9. When display returns to bL, press NEXT several times until the code LCC (Lock
Code Change) is displayed.
10. Press ENTER, then use the NEXT and increment (Δ) keys until the desired new
security code is displayed.
11. Press ENTER. The new code will now be required for all future entries.
12. Lock the Analyzer using the standard procedure.
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MI 611-190 – January 2021
4. Configuration
LCC Configuration Codes
Digit 1
Digit 2
Digit 3
4-digit Lock Code
0000 to 9999
70
Digit 4
5. Calibration
The Calibration section is divided into two main parts:
1. Electronic Bench Calibration
2. Calibration of a Sensor
The description of Electronic Bench Calibration contains the procedures for calibrating the
873DPX Analyzer with theoretical mV inputs.
The description of Calibration of a Sensor provides calibration procedures and standardization
techniques for individual sensors and solutions. These additional procedures are recommended
for verifying individual electrode functions and for achieving best system accuracy.
The section titled Temperature Cell Factor fine tunes the RTD temperature signal to agree with
actual temperature. This procedure must be followed if you use long cable lengths.
!
CAUTION
Do not remove the four front panel screws and the electronics package for calibration.
The self-tapping screws have a limited number of taps and will not function properly
with repeated use.
Electronic Bench Calibration
The procedure for calibrating 873 analyzers with theoretical mV inputs is as follows.
Figure 18. Flow Chart for Electronic Bench Calibration
Temp
FSC
CO1
CAL LO
CAL HI
NOTE
All 873 analyzers are calibrated and configured before shipment. You may verify
calibration by feeding mV values into the unit. Verification of proper operation of the
873 electronics can be an aid in troubleshooting a problem installation. If the unit
operates properly in this calibration, it may be ruled functional in the installation. If
the FSC was changed from the factory configured range, the analyzer should be bench
calibrated. Do not press ENTER if you are checking the calibration.
Note that once a sensor connected to the 873DPX is calibrated in pH buffers or standard
solutions, the theoretical values entered during the electronic bench calibration procedure are
removed.
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MI 611-190 – January 2021
5. Calibration
Equipment Required for Calibration
♦ Precision millivolt standard (0 to 1000 mV dc ±.1%)
♦ 110-ohm precision resistor for temperature simulation
Procedure
The procedure for performing bench calibration is:
1. Disconnect all sensor leads from analyzer.
2. Unlock analyzer (see ).
3. Check the temperature circuit calibration
a. Connect a 110-ohm resistor across sensor input terminals 1 and 2.
b. Press TEMP. The unit should then be in the Automatic Temperature mode and
no decimal should be visible after the C or F legend. If there is a decimal after the
C or F legend, remove it. To do so, press Δ once after pressing TEMP; then press
ENTER.
c. Reset tCF1 to 25.00 (the theoretical temperature transducer value).
d. Press TEMP. The display should read approximately 25ºC or 77ºF. If the display
does not read either of these values, reset the temperature electronics for
recalibration.
e. The unit should now be put into manual temperature mode. There should be a
decimal to the right of the legend. Press TEMP. Press Δ one or more times until
the display reads 25ºC. Press ENTER.
f. Use NEXT + Δ until the display reads (2)5.00 ºC. The first digit 2 will not be
displayed. Press ENTER.
4. Reset the Full Scale value of the analyzer. Refer to . Even if the existing Full Scale
Value is the desired value, it is important to reenter the same value. When the FSC
value is entered, error code Er4 should begin to flash on the display.
NOTE
1. If an Error Code of higher priority is present, it will preempt the Er4 message.
2. Holding the Shift key between entries will prevent the analyzer from timing out
and leaving the Setup entries.
5. Check and adjust the damping factor of the unit. Refer to CELL configuration in
Chapter 4. Set CELL to read “xx00”. The unit should have no damping and should
use the standard Nernstian compensation during calibration (CO1 or CO2 = X0X0).
72
5. Calibration
MI 611-190 – January 2021
6. Zero and Span Calibration
a. Connect a mV power supply to sensor input terminals — positive to 3 and
negative to 4 and 5.
b. Connect a jumper between sensor input terminals 4 and 5.
c. Adjust the mV supply to the desired low value as determined by the formula in
Table 5. Wait at least 15 seconds for the electronics to stabilize.*
d. Press SHIFT and while holding, press CAL LO. Release fingers from both keys.
Use NEXT and Δ until the display reads the desired low value. Press ENTER.
e. Calculate the mV input required for Calibrate High Value. The CAL HI value
should fall within the range of the FSC that has been chosen. *(For ORP, see
note.)
NOTE
* The Er4 code should stop flashing. An error of lower priority may begin to flash. See
Section 6
f. Input mV value corresponding to calculated CAL HI value. Wait at least
15 seconds for the electronics to stabilize.
g. Press SHIFT and while holding, press CAL HI. Release fingers from both keys.
Use NEXT and Δ until the display reads desired CAL HI value. Press ENTER.
7. Lock analyzer (see ).
8. This completes the Standard Electronics Bench Calibration procedure.s
Table 5. mV Supply Formulas
Measurement Mode
mV Power Supply Formula
Examples
Glass pH
(pH–7) x –59.16
pH 0: (0 – 7) x –59.16 = +414.1 mV
pH 14: (14 – 7) x –59.16 = –414.1 mV
Antimony pH
(pH–1) x –55
pH 0: (0 – 1) x –55.00 = +55.0 mV
pH 7: (7 – 1) x –55.00 = –330.0 mV
ORP
(mV) *
Input absolute mV
58/n x log[ppm/ppm(known)] Fluoride (F−)
+ mV known**
Charge is negative and monovalent (n= -1)
Known:
1 ppm F− = 0 mV
2 ppm: 58/(-1) x log[2/1] + 0 = -17.5 mV
20 ppm: 58/(-1) x log [20/1] + 0 = -75.5 mV
ppm (ISE)
NOTE
*ORP: Do not exceed an input voltage of 1700 mV. Suggested ORP calibration range
is ±900 mV. The lower limit is –999 mV, the upper limit is 1400 mV. Values up to
1700 mV can be displayed on the unit. Above this value, 9999 is displayed. Input
voltages exceeding 2000 mV will cause an Er 1 to occur.
73
MI 611-190 – January 2021
5. Calibration
NOTE
**ISE: Electronic calibration of ISEs requires prior knowledge of the charge and
valence of the ion (n) and the mV response of the ISE at a given concentration [ppm
(known) and mV known]. This data should be available in the literature provided by
the electrode manufacturer and may be expressed in a graph such as the example for a
fluoride electrode shown in Figure 19. If the calculated voltages do not fall within the
-150 to +150 mV span of the 873DPX, it may be necessary to change the offset
voltage (OF) to place the 300 mV span in the appropriate place within the range.
Figure 19. Fluoride Electrode Response as Function of Temperature
12.5°C (54.5°F)
0°C (32°F)
10.0
FLUORIDE (ppm)
5.0
25°C
77°F
3.0
1.5
TYPICAL
1.0
FLUORIDE
CONTENT
0.5
0.3
0.1
+60
74
+40
+20
mV
0
-20
-40
-60
5. Calibration
MI 611-190 – January 2021
Calibration Of A Sensor
General Information
In many circumstances, a sensor used on an analyzer that has been bench calibrated may provide
sufficient accuracy to the user. The electronic bench calibration establishes an approximate
relationship between pH or ppm values displayed and expected mV output from a sensor. In such
cases, you may connect the sensor to the analyzer and use it without further calibration.
A single point standardization using one buffer or standard solution, preferably near the process
measurement value, is often suitable for routine measurements. For the best possible system
accuracy, use a two point standardization, preferably bracketing the process control point. You
may also extract a sample from the process stream (i.e., a grab sample), perform a laboratory
analysis, and calibrate the analyzer with the results of the analysis. This is also a convenient way to
perform sample calibration as it allows the sensor to remain installed in the process during
standardization.
The electronic bench calibration is described earlier in this chapter. The other three commonly
used techniques are discussed in the following sections. In addition, a correction should be made
to correct temperature measurements that may differ from actual values (such as when sensor
cable length exceeds 50 feet). These procedures should be performed prior to sensor
standardization in buffers.
In all cases, these general guidelines should be observed:
1.
Clean sensors thoroughly before standardization.
2. Use fresh pH buffers or standard solutions.
3. Allow enough time for sensor and temperature-compensator to reach thermal
equilibrium. The temperature display should indicate the correct temperature of the
buffer.
4. For pH standardization, use the correct pH value of the buffer during standardization
— pH buffers have different values at different temperatures.
5. Allow sufficient time to reach thermal and chemical equilibrium.
6. Sensors must be properly grounded in solution during the standardization. The black
threads of the Model 871A sensors must be in contact with the solution.
75
MI 611-190 – January 2021
5. Calibration
Figure 20. Flow Chart for pH/ORP/ISE Sensor Calibration
Electronic
Bench
Calibration
Install
Sensor
Check Temp
Calibrate
tCF
Single Buffer/
Standard
Solution
OR
Two Buffer/
Standard
Solution
AND/OR
Grab
One and Two Point Calibration
Figure 21. Flow Chart for Single Point Calibration
Sensor
Remove
Immerse in
Buffer/
Standard
Clean
CAL LO
Figure 22. Flow Chart for Two Point Calibration
Sensor
Remove
Clean
Low
Buffer/
Standard
Rinse
CAL LO
The procedure for performing one and two point calibration is as follows:
76
High
Buffer/
Standard
CAL HIGH
5. Calibration
MI 611-190 – January 2021
1. Unlock analyzer (see ).
2. Remove the sensor from the process stream. Clean the immersion end and rinse with
distilled water.
3. Select buffers or standard solutions near or bracketing the process measurement value.
The solutions should be at the same temperature and, for best results, near the process
temperature.
4. Immerse the cleaned sensor in the solution with lower known pH, ORP, or ion
concentration. Wait until the sensor has reached chemical and thermal equilibrium.
5. Press/hold SHIFT and press CAL LO. Remove fingers from both keys.
6. Press NEXT and Δ repeatedly until the display reads the correct value at the
temperature of measurement. Press ENTER.
NOTE
For single point standardization, stop here. The slope (gain) from the previous bench
or solution calibration will be used.
7. Thoroughly rinse the sensor in distilled water.
8. Immerse the sensor in the second solution with higher known pH, ORP, or ion
concentration. Allow the sensor to come to chemical and thermal equilibrium.
9. Press SHIFT and while holding, press CAL HI. Remove fingers from both keys.
10. Use NEXT and Δ until display reads the correct value. Press ENTER.
11. Lock analyzer (see “Locking Analyzer Using Security Code” on page 38).
Grab Sample Standardization
Figure 23. Flow Chart for Grab Sample Calibration
Sample
Note
Analyze
Correct
CAL LO
77
MI 611-190 – January 2021
5. Calibration
The procedure for grab sample calibration is:
1. Unlock analyzer (see “Unlocking Analyzer Using Security Code” on page 38).
2. Note the present pH, ORP, or ion concentration reading while extracting a sample
from the process stream.
3. Determine the pH (ORP or ion content) of the sample using laboratory techniques
suitable for the precision required. The laboratory measurement should include
precise standardization and temperature compensation of the laboratory sensor, and
should protect the sample from atmosphere and temperature change.
4. Determine the difference between the laboratory value and process reading taken
when the sample was removed.
5. Using the CAL LO sequence, adjust the present reading by the difference calculated.
EXAMPLE:
When the sample was taken, the analyzer read 8.25 pH. The grab sample was found by the
laboratory to be 8.40 pH. When you returned to the analyzer, the display read 8.30 pH. This
value should be increased by +.15 pH units (8.40 – 8.25 =.15) to 8.45 using the CAL LO key
and Δ.
6. Press SHIFT and while holding, press CAL LO. Remove fingers from both keys.
7. Use NEXT and Δ until the display reads the corrected measurement value. Press
ENTER.
8. Repeat Steps 2 through 7 to verify the standardization.
Temperature Cell Factor
Except for ORP measurements, which do not use temperature compensation, an accurate
temperature signal is required, especially when measuring over a large temperature gradient. The
temperature cell factors (tCF1 and tCF2) are used to offset a deviation from ideal caused by high
cable resistance. The procedures found in the following sections are recommended for
installations that require a cable length of 50 feet or greater. The 873 analyzer uses a 100-ohm
RTD circuit for automatic temperature compensation. Use this procedure before executing buffer
or grab sample calibrations.
78
5. Calibration
MI 611-190 – January 2021
Determining tCF
The procedure for determining the temperature cell factor is:
1. Place the sensor and an accurate Centigrade thermometer (with 1.00 ºC resolution)
into a container of liquid. Allow the system 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, remove it. 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 current temperature value with tenths place display will
alternate with the C legend. The value read by the 873 may 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 ºC, and the 873 reads (2)5.20 ºC; the 873 is reading higher
by 0.50 ºC.
5. Subtract this value from 25.00 (e.g., 25.00 –.50 = 24.50). This is your new tCF value.
NOTE
If the 873 value is less than the thermometer reading, add the difference to 25.00.
Entering a tCF Value
To enter a tCF value, execute the following procedure:
1. Unlock analyzer (see “Unlocking Analyzer Using Security Code” on page 38).
2. Press SHIFT + SETUP. Release both keys.
3. Press NEXT several times until the code bL (Basic Setup Lock) is displayed.
4. Press ENTER. Then press NEXT and Δ repeatedly until personal security code is
displayed (0800 from factory).
5. Press ENTER.
6. When the display returns to bL, press NEXT several times until the parameter
identifier tCF1 or tCF2 is displayed.
7. Press ENTER and then press NEXT and Δ one or more times until desired value is
displayed.
8. Press ENTER.
9. Recheck any differences that exist between a thermometer reading and the
temperature displayed on the 873, using the technique described earlier in this
chapter.
10. Lock analyzer.
79
MI 611-190 – January 2021
80
5. Calibration
6. Diagnostics
Troubleshooting
Using the 873 Analyzer to Troubleshoot a Sensor Problem
The best way to check the health of a sensor is to hook it up to an analyzer and to calibrate it in
pH buffers or standard solutions (refer to “One and Two Point Calibration” on page 76). First,
make sure that buffers or standard solutions are fresh and uncontaminated. Then, let the sensor
reach thermal and chemical equilibrium with the solution. If the sensor calibrates accurately, you
can be sure it is fully functional. If it does not, refer to the section on “Additional
Troubleshooting” on page 83.
873 Error Codes/Actions
When the sensor is used in conjunction with an 873 analyzer, the analyzer displays an error code
if certain fault conditions exist. (Refer to Table 7, “Error/Alarm Messages,” on page 85 for an
explanation of each.) Use of the error codes in diagnosing sensor problems is described below.
Er 1 (Instrument Fault):
♦ Disconnect the sensor and power down the analyzer. Try the sensor on another unit.
Er 2 (Temperature Error):
♦ The temperature sensor used on the 873DPX is a 100 ohm RTD. At temperatures
around 25°C (77°F), it should read 110 ohms. Check to see what values (typically 0
to 100) are assigned to tL and LtL. Then press TEMP (Auto mode). If the display
reads incorrectly, determine whether the analyzer or sensor is not functioning. To
check the analyzer, place a 110-ohm resistor across Terminals 1 and 2 of terminal
block TB2 and verify that the analyzer reads 25 ºC. If it does not, a fault exists in the
analyzer. If it does, proceed to the next step.
♦ Next, measure the resistance between wires 1 and 2 (black and white) of the sensor. At
normal room temperatures, the resistance should be approximately 110 ohms. If the
resistance between Leads 1 and 2 of the sensor deviates greatly from 110 ohms, the
sensor is not functioning properly and should be replaced. For the short term, if the
process measurement does not change temperature and is close to pH 7, or has very
wide accuracy specifications, manual temperature compensation may be selected.
81
MI 611-190 – January 2021
6. Diagnostics
Er 4 (Calibration Error):
♦ During 2-point calibration with fresh non-contaminated solutions, a sensor may cause
an Er 4 error message to appear if the sensor does not generate a large enough voltage
difference between the two measurements. If, however, the sensor is sufficiently
conditioned and relatively stable in each solution, additional conditioning time may
improve the response. Soak your electrode in dilute KCl solution without silver
chloride. To hydrate the glass bulb, soak sensor in pH 4 buffer solution for
approximately 15 minutes.
♦ Note that a new sensor installation may also experience this problem. Recovery may
be hastened by immersing the sensor in a warmed KCl solution and then cooling it to
room temperature while immersed in this solution. If the sensor reads the same value
in every solution after hydration and proper conditioning, replace the sensor.
♦ The 873DPX analyzer will accept a 2-buffer calibration (Er 4 not activated) as long as
the slope (mV/pH or mV/ppm decade) of the calibration curve (see Figure 24)
exceeds ~50 mV. Slope value may be accessed by pressing SHIFT + SLOPE. Slope is
always displayed at a temperature of 25.0 ºC, regardless of the temperature at which
calibration occurred. If the slope falls below 50.3, the calibration will still be accepted
into the unit, but Er 4 will flash and alternately display the sample value.
Sensor servicing is recommended on all sensors with slopes below 53.3 mV/pH
(90% efficiency). See Item 2, “Low Slope”, in the following section.
Verify that the temperature is reading correctly and the analyzer is in the automatic
temperature mode. See Chapter 3
♦ Use the correct buffer values at the temperature of measurement.
Table 6. Temperature vs. Resistance Table for Pt 100 RTD
82
Temperature
(°C)
Resistance
(ohms)
Temperature
(°C)
Resistance
(ohms)
–5
0
5
10
15
20
25
30
35
98.04
100.00
101.95
103.90
105.85
107.79
109.73
111.67
113.61
40
50
60
70
80
90
100
110
115.54
119.40
123.24
127.07
130.89
134.70
138.50
142.29
6. Diagnostics
MI 611-190 – January 2021
Additional Troubleshooting
1. SENSOR DOES NOT APPEAR TO BE FUNCTIONING.
For sensors with a preamplifier, leave all sensor leads connected to the analyzer. Leave
analyzer power on. Connect a voltmeter first to Leads 4 and 6 of TB2, and then to
Leads 4 and 7. The voltmeter should read ±6.2 V. If it does not, disconnect the sensor
and repeat the procedure at the analyzer. If ±6.2 V can be measured at the analyzer
terminals, a problem exists in the sensor. If ±6.2 V is not present at the analyzer
terminals, an analyzer problem exists. If the sensor and analyzer both pass this test,
continue to Item 2.
2. LOW SLOPE.
Leave all sensor leads connected to the powered analyzer. Clean the “business end” of
the sensor and place into a beaker of pH 7 buffer. Use the mV key to display the
measured absolute voltage generated by the sensing and reference electrodes. The
value should be 0 V ±20 mV. When the sensor is cleaned and placed into a second
buffer (25 ºC), the reading should change approximately 59 mV per pH unit. In a
10.0 pH buffer, the mV reading should be less than the 7 pH buffer reading by
approximately 174 mV (177.3 theoretically). In a 4.00 pH buffer, the mV value
should be greater than the mV value in the 7 pH buffer by 174 mV. If the sensor
passes this test and the problem with the measurement persists, an analyzer problem
may exist. Verify that the sensor temperature is in automatic mode and that it is
reading correctly.
NOTE
HINT: It is a good idea to keep records of your calibrations. Recording the mV values
and Slope can help you establish maintenance and replacement information on your
sensors.
3. ERRATIC READING.
On 871PH pH/ORP/ISE only: Measure the resistance between wire #4 (clear) and
the knurled screw on the immersion end of the sensor. The resistance should be 0
(shorted) or very small. If not, you have a grounding problem with your sensor.
For an 871A, make sure the grounding threads are in contact with the solution. Teflon
tape around these threads may prevent a ground connection from being made.
Troubleshooting a ground loop or grounding problem may also be done in a beaker of
buffer. Immerse a sensor in buffer other than pH 7 and note the pH. Attach a wire to
a piece of metal (a paper clip will do) and to an earth ground (metal pipe or outlet
ground). Next, place the metal piece into the beaker and observe the pH reading of
the analyzer. It should not change. A change in pH during this procedure indicates
that a problem exists.
83
MI 611-190 – January 2021
6. Diagnostics
4. SLOW RESPONSE.
If the sensor is very slow in responding, a blockage may have occurred on the reference
junction. (To dissolve dried salts, condition the sensor longer. Otherwise, replace the
reference solution, especially if it is discolored.) Trapped air bubbles can also cause
problems by increasing resistance in this circuit. A firm shakedown and soaking can
often help. Slow response can also indicate a coated or dehydrated pH glass. Although
cleaning or soaking the sensor in pH 4 buffer or dilute acid may help, replacement of
the pH electrode may be required. Also refer to the Er 4 troubleshooting procedures
described earlier in this section.
600
TEMPERATURE (C)
Cal Lo
500
SLOPE (MV)
0
25
50
75
100
400
300
54.2
59.2
64.1
68.1
74.0
200
100
mV
ISOPOTENTIAL POINT
0
-100
-200
Cal Hi
-300
0C
25 C
50 C
70 C
-400
-500
-600
100 C
0
2
4
6
8
10
12
14
pH
Figure 24. Relationship between pH and mV at Different Temperatures
for a Standard Glass pH Sensor and Ag/AgCl Reference Electrode
84
6. Diagnostics
MI 611-190 – January 2021
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 the
following tables.
Table 7. Error/Alarm Messages
Alternate
Display
Condition
Priority
Action Required to Clear Error Message
Er1
Instrument fault, RAM/ROM, software
watchdog timer
1
(highest)
1.
2.
Re-enter security code.
Power cycle unit.
Er2
User-defined temperature range error or
temperature measurement error
6
1.
Change user-defined temperature
limits, UtL or LtL.
Replace sensor.
Place temperature in manual mode.
2.
3.
Er3
User-defined measurement range error
7
1.
Change user-defined measurement
limits, UL or LL.
2. Replace sensor.
3. Ground loop.
Er4
Measurement calibration incorrect
2
1.
Al 1
Alarm 1 relay activated
9
Al 2
Alarm 2 relay activated
9
A1A2
Both alarm relays activated
8
....
Measurement over or under range of
analog output limits
10
Check analog output limits.
Err
Incorrect code or parameter attempted
2
Check code and re-enter.
Recalibrate sensors on both
channels.
85
MI 611-190 – January 2021
86
6. Diagnostics
7. 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 load of 20 W or more as shown in Figure 25 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.
Figure 25. Alarm Contact Reconditioning Circuit
NO
C
20 W LOAD
120 V ac SUPPLY
NC
87
MI 611-190 – January 2021
ISSUE DATES
JAN 1996
JUN 1996
OCT 1997
JUN 2004
FEB 2016
AUG 2016
JAN 2021
Vertical lines to the right of text or illustrations indicate areas changed at last issue date.
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Foxboro, MA 02035
United States of America
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USA, Inc. All rights reserved.
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