GF Signet 8850-2 User manual

page 1 of 12‡ SIGNET 8850-2 Conductivity/Resistivity Transmitter
Conductivity/Resistivity
62.50 uS
25.0°C
Relay 1 Relay 2
ENTER
‡ SIGNET 8850-2 Conductivity/Resistivity Transmitter ENGLI H
2. pecifications
General
Compatible electrodes: GF SIGNET 3-28XX-1 Standard and
Certified (NIST) Series Conductivity/Resistivity Electrodes
Accuracy: ±2% of reading
Enclosure:
• Rating: NEMA 4X/IP65 front
• Case: PBT
• Panel case gasket: Neoprene
• Window: Polyurethane coated polycarbonate
• Keypad: Sealed 4-key silicone rubber
• Weight: Approx. 325g (12 oz.)
Display:
• Alphanumeric 2 x 16 LCD
• Contrast: User selected, 5 levels
• Update rate: 1 second
Electrical
Power: 12 to 24 VDC ±10%, regulated, 290 mA max.
Sensor input range:
• Conductance: 0.055 to 400,000 µS
• Resistivity: 10 KΩ to 18.2 MΩ
• TDS: 0.023 to 200,000 ppm
( Measurements from 10 MΩ to 18 MΩ (0.055 µS to 0.1 µS) must
be performed in solution temperatures from 20 °C to 100 °C. )
• Temperature: PT 1000, -25 to 120°C (-13 to 248°F)
Current output:
• 4 to 20 mA, isolated, fully adjustable and reversible
• Max loop impedance: 50 Ω max. @ 12 V
325 Ω max. @ 18 V
600 Ω max. @ 24 V
• Update rate: 0.5 seconds
• Accuracy: ±0.03 mA @ 25°C, 24 V
Relay outputs (2 sets mechanical SPDT contacts):
• Maximum voltage rating:
5 A @ 30 VDC, or 5 A @ 250 VAC, resistive load
• Hi or Lo programmable with adjustable hysteresis
• Pulse programmable (maximum 400 pulses/minute)
Environmental
• Operating temperature: -10 to 70°C (14 to 158°F)
• Storage temperature: -15 to 80°C (5 to 176°F)
• Relative humidity: 0 to 95%, non-condensing
• Maximum altitude: 2000 m (6562 ft)
• Insulation category: II
• Pollution degree: 2
tandards and Approvals
• CSA, CE, UL listed
• Immunity: EN50082-2
• Emissions: EN55011
• Safety: EN61010
• Manufactured under ISO 9001 and ISO 14001
U. .A. Patent # 5,708,363
3-8850.090-2
CAUTION!
• Remove power to unit before wiring
input and output connections.
• Follow instructions carefully to avoid
personal injury.
Contents
1. Installation
2. Specifications
3. Electrical Connections
4. Menu Functions
1. Installation
ProcessPro transmitters are available in two styles: panel mount and field mount. The panel mount is supplied with the necessary
hardware to install the transmitter. This manual includes complete panel mounting instructions.
Field mounting requires a separate mounting kit. The 3-8050 Universal kit enables the transmitter to be installed virtually
anywhere. Detailed instructions for field installation options are included with the 3-8050 Universal kit.
1.1 Panel Installation
1. The panel mount transmitter is designed for installation using a 1/4 DIN Punch. For manual panel cutout, an adhesive
template is provided as an installation guide. Recommended clearance on all sides between instruments is 1 inch.
2. Place gasket on instrument, and install in panel.
3. Slide mounting bracket over back of instrument until quick-clips snap into latches on side of instrument.
4. To remove, secure instrument temporarily with tape from front or grip from rear of instrument. DO NOT RELEASE.
Press quick-clips outward and remove.
SIDE VIEW
92 mm
(3.6 in.)
97 mm
(3.8 in.)
56 mm
(2.2 in.)
41 mm
(1.6 in.
)
Optional
Rear
Cover
Field Mount Panel Mount
FRONT VIEW
96 mm
(3.8 in.)
96 mm
(3.8 in.)
quick-clips
gasket panel
terminals mounting
bracket
latch
Output -
Output +
ystem Pwr
Loop -
ystem Pwr
Loop +
2
14
3
ensr Gnd
(HIELD)
ensr IN
(RED)
ensr V+
(BLACK)
7
6
5
SIDE VIEW
Field Mount &
Panel Mount
Panel Mount
Installation Detail
106 mm
(4.18 in.)
82 mm
(3.23 in.)
D-10/01 English

page 2 of 12 ‡ SIGNET 8850-2 Conductivity/Resistivity Transmitter
System Pwr
Loop -
System Pwr
Loop +
AUX
Power -
AUX
Power +
4
3
2
1
Sensr Gnd
(SHIELD)
Iso Gnd
(BLACK)
Temp IN
(WHITE)
Signal IN
(RED)
14
13
12
11
Relay 2
(NO)
Relay 2
(COM)
Relay 2
(NC)
Relay 1
(NO)
Relay 1
(COM)
Relay 1
(NC)
10
9
8
7
6
5
3. Electrical Connections
Caution: Failure to fully open terminal jaws before removing wire may permanently damage instrument.
Wiring Procedure
1. Remove 0.5 - 0.625 in. (13-16 mm) of insulation from wire end.
2. Press the orange terminal lever downward with a small screwdriver to open terminal jaws.
3. Insert exposed (non-insulated) wire end in terminal hole until it bottoms out.
4. Release orange terminal lever to secure wire in place. Gently pull on each wire to ensure a good connection.
Wiring Removal Procedure
1. Press the orange terminal lever downward with a small screwdriver to open terminal jaws.
2. When fully open, remove wire from terminal.
2
1
Terminals 5-10: Relay Outputs
• Two SPDT mechanical relays, programmable as:
• High or Low setpoint with adjustable hysteresis.
• Proportional Pulse (400 pulses per minute maximum).
• May be disabled (Off) if not used.
Terminals 3 and 4: Loop Power
12-24 VDC ±10% system power
and current loop output.
Max. loop impedance:
50 Ω max. @ 12 V
325 Ω max. @ 18 V
600 Ω max. @ 24 V
Terminals 11-14: ensor input
11 is conductivity input
12 is temperature input
13 is the isolated signal ground
14 is the sensor earth ground
Terminals 1-2: Auxiliary power
Provides DC power to measurement circuit.
Required for all 8850 systems

page 3 of 12‡ SIGNET 8850-2 Conductivity/Resistivity Transmitter
3.1 ystem Power/Loop Connections
Stand-alone application, no current loop used
Transmitter
4
3
2
1
Sys. Pwr.
Loop -
Sys. Pwr.
Loop +
AUX
Power -
AUX
Power +
Power Supply
DC 12 - 24 V
Power
Supply
Power
Supply
Connection to a PLC with built-in power supply
PLC
Power Supply
Ground
Power
Supply
Loop Input
-20 mA
Loop Input
-20 mA
Internal PLC
Connection
Connection to a PLC/Recorder, separate supply
PLC or Recorder
Loop Input
-20 mA in
Loop Input
-20 mA in
DC 12 - 24 V
Power
Supply
Power
Supply
Example: Two transmitters connected to PLC/Recorder
with separate power supply
Transmitter 2
4
3
2
1
DC 12 - 24 V
Power
Supply
Power
Supply
Transmitter 1
4
3
2
1
Transmitter
4
3
2
1
Sys. Pwr.
Loop -
Sys. Pwr.
Loop +
AUX
Power -
AUX
Power +
Transmitter
4
3
2
1
Sys. Pwr.
Loop -
Sys. Pwr.
Loop +
AUX
Power -
AUX
Power +
Sys. Pwr.
Loop -
Sys. Pwr.
Loop +
AUX
Power -
AUX
Power +
Sys. Pwr.
Loop -
Sys. Pwr.
Loop +
AUX
Power -
AUX
Power +
PLC or Recorder
Channel 1
-20 mA in
Channel 1
-20 mA in
Channel 2
-20 mA in
Channel 2
-20 mA in
Terminals
Terminals
Terminals Terminals
-
+
-
+
-
+
-
+
-
+
-
+
-
+
AUX power required for all 8850 systems
3.2 ensor Input Connections
Wiring Tips:
• Do not route sensor cable in conduit containing AC power wiring. Electrical noise may interfere with sensor signal.
• Routing sensor cable in grounded metal conduit will help prevent electrical noise and mechanical damage.
• Seal cable entry points to prevent moisture damage.
• Only one wire should be inserted into a terminal. Splice double wires outside the terminal.
(18 MΩ) (10 kΩ)
2819-1
2823-1
Conductivity Range (µ )
+GF+ IGNET ensor Ranges
ensor Models
Ultra-
Pure Rinse
Pure
2821-1
2822-1
2820-1
0.055 1 10 100 200 1,000 10,000 200,000 400,000
Select the sensor with a range closest to your process minimum
and maximum values.
• 2819-1 (0.01 cell): 0.055 to 100 µS (10 kΩ to 18 MΩ)
Use the 2819-1 for all resistivity requirements
• 2820-1 (0.1 cell): 1 to 1000 µS
• 2821-1 (1.0 cell): 10 to 10,000 µS
• 2822-1 (10.0 cell): 100 to 200,000 µS
• 2823-1 (20.0 cell): 200 to 400,000 µS
14
13
12
11
Shield (Sensor Gnd)
Black (Iso Gnd)
White (Temp In)
Red (Signal In)
GF SIGNET 28XX-1
Standard and Certified Cells
Terminals
≤ 100 ft. (30 m)
62.50 uS/cm
25.0°C
ENTER
Conductivity/Resistivity

page 4 of 12 ‡ SIGNET 8850-2 Conductivity/Resistivity Transmitter
Hysteresis
Time
Low etpoint
Process
Relay energized¤
Relay relaxed
Hysteresis
Time
High etpoint
Process
3.3 Relay Output
The relays can be used as a switch that responds when the
process value moves above or below a setpoint, or to generate a
pulse at a rate proportional to the process value.
•Low:
Relay triggers when process is less than the setpoint.
The relay will relax when the process moves above the setpoint
plus the hysteresis value.
•High:
Relay triggers when process is greater than the setpoint.
The relay will relax when the process moves below the setpoint
plus the hysteresis value.
Conductivity/Resistivity
62.50 uS
25.0°C
Relay 1 Relay 2
ENTER
VIEW menu
• During normal operation, ProcessPro displays the VIEW menu.
• When editing the CALIBRATE or OPTIONS menus, ProcessPro will return to the VIEW menu if no
activity occurs for 10 minutes.
• To select a VIEW display, press the UP or DOWN keys. The selections will scroll in a continuous loop.
• Changing the VIEW display does not interrupt system operations.
• No key code is necessary to change display selection.
• Output settings cannot be edited from the VIEW menu.
1234.5 µS
+67.89 ºC
Loop Output:
13.75 mA
Last CAL:
06-30-01
Monitor the Conductivity and temperature values from the sensor.
This is the permanent display.
Monitor the Loop Current output.
Check the Last Calibration date.
The VIEW displays below are temporary. The permanent display will return after 10 minutes
•Proportional Pulsing
The relay will generate a 100 mS pulse at the rate defined by
settings in the CALIBRATE menu.
In the example below:
• The output will be 0 pulses/min. when value is less than 5.
• The output will be 50 pulses/min. when value is 7.5.
• The output will be 100 when value is greater than 10.
The starting point, endpoint and maximum pulse rate are
selectable in the CALIBRATE menu.
10
5
Relay Output Rate:
0 to 100 Pulses/min.
endpoint
Pulse rate
0 pulses
100 pulses
Starting point
View Menu
Display Description

page 5 of 12‡ SIGNET 8850-2 Conductivity/Resistivity Transmitter
Notes on teps 5 and 6:
• All output functions remain active during editing.
• Only the flashing element can be edited.
• RIGHT ARROW key advances the flashing element in a continuous loop.
• Edited value is effective immediately after pressing ENTER key.
• If no key is pressed for 10 minutes unit will restore the last saved value and return to step 3.
• Step 6 (pressing ENTER key) always returns you to Step 3.
• Repeat steps 3-6 until all editing is completed.
Notes on tep 2:
If no key is pressed for 5 minutes while display is showing "Enter
Key Code", the display will return to the VIEW menu.
Notes on teps 3 and 4:
• Refer to pages 6 and 7 for complete listing of menu items and their use.
• From the Step 3 display, pressing the UP and DOWN keys simultaneously will
return the display to the VIEW menu.
• If no key is pressed for 10 minutes, display will also return to the VIEW menu.
ProcessPro Editing Procedure:
tep 1. Press and hold ENTER key:
• 2 seconds to select the CALIBRATE menu.
• 5 seconds to select the OPTIONS menu.
tep 2. The Key Code is UP-UP-UP-DOWN keys in sequence.
• After entering the Key Code, the display will show the first item in the selected menu.
tep 3. croll menu with UP or DOWN arrow keys.
tep 4. Press RIGHT ARROW key to select menu item to be edited.
• The first display element will begin flashing.
tep 5. Press UP or DOWN keys to edit the flashing element.
• RIGHT ARROW key advances the flashing element.
tep 6. Press ENTER key to save the new setting and return to tep 3.
OPTION
CALIBRATE
VIEW
2s 5s
Press &
hold for
access:
ENTER
tep 5
tep 6
Notes on tep 1:
• The View Menu is normally displayed.
• The CALIBRATE and OPTIONS menus require a KEY CODE.
tep 4
First item in
CALIBRATE menu
tep 3
tep 3: Finished Editing?
Press the UP and DOWN keys simultaneously after
saving the last setting to return to normal operation.
Press the UP and DOWN keys simultaneously
while any element is flashing. This will recall the
last saved value of the item being edited and
return you to Step 3.
tep 5: Made an Error?
Relay1 Setpnt:
2 0.00 uS
Relay1 Setpnt:
1 0.00 uS
ENTER
Relay1 Setpnt:
10.00 uS
Relay1 Setpnt:
1
9
.00 uS
Relay1 Setpnt:
Saving
Relay1 Setpnt:
19.00 uS >
20.0 uS >
Relay1 Setpnt:
Standard >
Cell Constant:
CALIBRATE: ----
Enter Key Code
CALIBRATE: *---
Enter Key Code
CALIBRATE: **--
Enter Key Code
CALIBRATE: ***-
Enter Key Code
Standard >
Cell Constant:

page 6 of 12 ‡ SIGNET 8850-2 Conductivity/Resistivity Transmitter
Cell Constant:
Standard >
Cell: Standard
1>
Cell: Custom
1.0000 >
Cond Units:
µS>
PPM Factor:
2.00 >
Set:
Temperature >
Set:
Conductivity >
Loop Source:
Cond >
Loop Range: µS
0.0000 →100.000 >
Relay1 Source:
Cond >
Relay1 Mode:
Low >
Relay1 Setpnt:
10.0000 µS>
Relay1 Hys: µS
0.5000 >
Relay1 Rng: µS
10.0000 →40.0000 >
Relay1 PlsRate:
120 Pulses/Min >
Last CAL:
06-30-01 >
Select CUSTOM only if you are connecting a certified conductivity sensor. Select
STANDARD for all other systems.
For STANDARD sensors: Select from these options: 0.01, 0.1, 1.0, 10.0 or 20.0.
For CUSTOM sensors: Enter the precise cell constant from the certificate provided with
your sensor, or from the information label on the sensor.
Select from these options: µS/cm, mS/cm, kΩ•cm, MΩ•cm, PPB
If the Units selection is PPM, set the ratio of Total Dissolved Solids to µS. The maximum
allowable is 3 µS = 1 PPM. The TDS factor can only be set in PPM.
Adjust the temperature of the system based on an accurate external reference.
For use with STANDARD sensors: Perform this single-point wet calibration for most
accurate results. Not required for CUSTOM sensors except for periodic system accuracy
confirmation. Enter all zeroes to restore factory calibration to TEMP and COND settings.
Select the input (Conductivity or Temperature) source to be associated with the current
loop output:
Select the minimum and maximum values for the current loop output.
Be sure to modify this setting if you change the Cond. Units.
Select the source (Conductivity or Temperature) for this relay output:
Select the mode of operation for the relay.
Options available are High, Low or proportional Pulse.
The relay may be disabled (Off) if not in use.
In Low or High Mode, the relay will be activated when the process reaches this value. Be
sure to modify this setting if you change the Cond. Units.
The relay will be deactivated at Setpoint ± Hysteresis, depending on High or Low Setpoint
selection.
In Pulse mode, set the process values where the proportional pulse will start and where it
will reach the maximum rate. Be sure to modify this setting if you change the Cond. Units.
In Pulse mode, set the maximum rate for the proportional Pulse. The 8850 will accept any
value from 0 to 400.
Use this “note pad” to record important dates, such as annual recertification or scheduled
maintenance.
Calibrate Menu
Display
(Factory settings shown) Description

page 7 of 12‡ SIGNET 8850-2 Conductivity/Resistivity Transmitter
Adjust the LCD contrast for best viewing. A setting of 1 is lower contrast, 5 is higher. In
general, select lower contrast if the display is in warmer ambient surroundings.
Set the decimal to the best resolution for your application. The display will automatically
scale up to this restriction. Select *****., ****.*, ***.** **.*** or *.****
OFF provides the most instantaneous response to process changes. Select LOW (4 sec)
or HIGH (8 sec) averaging if your process experiences frequent or extreme fluctuations.
Adjust the minimum and maximum current output. The display value represents the
precise current output. Adjustment limits:
• 3.80 mA < 4.00 mA > 5.00 mA
• 19.00 mA < 20.00 mA > 21.00 mA
Use this setting to match the system output to any external device.
Select ºC or ºF.
Set the percent change in Conductivity caused by a 1ºC change in temperature. May be
from 0.00 to 10.00.
Press UP and DOWN keys to manually order any output current value from 3.8 mA to
21.00 mA to test the output loop.
Press UP and DOWN keys to manually toggle the relay state.
Contrast:
3>
Cond Decimal:
****.* >
Averaging:
Off >
Loop Adjust:
4.00 mA >
Loop Adjust:
20.00 mA >
Temp Display:
ºC>
Temperature
Comp %: 2.00 >
Test Loop:
>
Test Relay1:
>
Options Menu
Display
(Factory settings shown) Description

page 8 of 12 ‡ SIGNET 8850-2 Conductivity/Resistivity Transmitter
Calibration Procedure
This instrument has been electronically calibrated at the factory.
• Procedure A verifies the accuracy and linearity of the instrument by simulating temperature and conductivity values with precision
(±0.1%) fixed resistors.
• Procedure B is a wet calibration. This procedure uses the sensor input and NIST traceable test solutions. When done correctly,
this procedure offers the most accurate system calibration.
Iso. Gnd
(BLACK)
Temp. IN
(WHITE)
ignal IN
(RED)
9
8
7Simulation resistor
TC resistor
B) Wet Calibration with NI T Traceable olutions:
When using NIST traceable standards, review the temperature information provided with the test solution. Prevent contamination of the
test solution. The sensor must be at the temperature specified on the test solution label.
• Remove the sensor from the system. Rinse the sensor in a small amount of test solution.
• Place the sensor into the test solution.
• Place a reference thermometer into the same solution.
• Allow sufficient time for the temperature to stabilize.
• Set Temp: Adjust the temperature value based on the reference thermometer. (see Editing Procedure.)
• Set Cond: Adjust the conductivity value based on the test solution value. (see Editing Procedure.)
• Verify the linearity by placing the sensor into a second test solution of a different value.
• If the instrument does not display the correct value (Temperature ± 0.5 ºC, Conductivity ± 2% of reading), service is required.
A) Accuracy Verification with Precision Resistors (Electronic Calibration):
1. imulate the Temperature
The temperature input to the 8850 is a PT-1000 thermistor, where 1000 Ohms (Ω) is equal to 0 ºC and a change of 3.84 Ω equals
a 1ºC change. (1000 Ω = 0 ºC, 1003.84 Ω = 1.0 ºC, 1007.68 Ω = 2.0 ºC...................1096 Ω = 25 ºC)
• Connect a resistor (1000 Ω to 1096 Ω ) between "Temp IN" and "Iso. Gnd" terminals.
• Set Temp; Adjust the temperature to exact value based on the measured resistance. (see Editing Procedure, Calibrate menu).
• To verify the temperature linearity, connect a second resistor value to the terminals.
• If the instrument does not display the correct value, service is required. ( ± 0.5 ºC)
2. imulate the Conductivity
You may calculate the exact Resistance needed to simulate a specific conductivity value , or you may calculate the exact Conductivity
based on a resistor value:
Resistance = Cell constant e.g. 0.1 Cell = 5,000 Ω or 5 KΩ
conductivity (Siemens*) 0.000020 (Siemens*)
Conductivity = Sensor cell e.g. 0.1 Cell = 0.000001 Siemens*
Simulation resistance (Ω) 100,000 (Ω) or 1µS/cm
(*1 µS = 1 X 10-6 Siemens or 0.000001 Siemens)
• Connect the conductivity resistor between the "Signal IN " and "Iso Gnd" terminals.
• Set Cond: Adjust the conductivity value based on the resistor value. (see Editing
Procedure and Calibrate menu).
• Verify the linearity of the instrument by connecting a second resistor of a different value.
• If the instrument does not display the correct value (± 2% of reading), service is required.

page 9 of 12‡ SIGNET 8850-2 Conductivity/Resistivity Transmitter
Parts Per Million (PPM) Factor
This feature is only applicable when PPM display units are selected. The programmable PPM Factor is adjustable from 0.01 to
3.00 (factory default = 2.00).
Determine the best PPM Factor for a process solution by calculating the solution's conductivity (µS) and the percent of total
dissolved solids (PPM).
PPM Factor = Solution conductivity (µS/cm)
Total dissolved solids (PPM)
TDS (PPM) = Solution conductivity (µS/cm)
PPM Factor
Example: • Solution conductivity = 400 µS/cm
• TDS = 200 PPM (mg/L)
PPM Factor = 400 µS/cm = 2.00
200 PPM
Temperature Coefficient
Conductivity measurement is highly dependent on temperature. Temperature dependence is expressed as the relative change per °C,
commonly known as percent/°C change from 25°C, or slope of the solution.
Slopes can vary significantly depending on process solution type. The factory default temperature compensation factor is 2.00%/°C.
Process solutions may require adjustment for maximum accuracy. To determine the optimum temperature compensation factor for a
process:
1. Disable the 8850 temperature compensation % factor by entering 0.00.
2. Heat the sample solution close to the maximum process temperature. Place sensor in the sample solution allowing several
minutes for stabilization. Access the VIEW menu and record the displayed temperature and conductivity values in the spaces
provided:
Displayed temperature: T1 = _______ °C
Displayed conductivity: C1 = _______ °C
(Do not use this procedure for solutions from 0.055 µS to 0.1 µS (10 MΩ to 18 MΩ). An internal pure water curve is used for these
ranges. The factory default setting of 2.00%/°C should be used.)
3. Cool the sample solution close to the minimum process temperature. Place sensor in the sample solution allowing several
minutes for stabilization. Record displayed temperature and conductivity values in the spaces provided:
Displayed temperature: T2 = _______ °C
Displayed conductivity: C2 = _______ °C
(A 10% change in conductivity between steps 2 and 3 is recommended.)
4. Substitute recorded readings (steps 2 and 3) into the following formula:
TC Slope = 100 x (C1 - C2)
(C2 x (T1 - 25)) - (C1 x (T2 - 25))
Example: A sample solution has a conductivity of 205 µS @ 48°C. After cooling the solution, the conductivity was measured at
150 µS @ 23 °C. (C1 = 205, T1 = 48, C2 = 150, T2 = 23)
The TC is calculated as follows:
TC Slope = 100 x (205 - 150) = 5500 = 1.42%/°C
(150 x (48 - 25)) - (205 x (23 - 25)) 3860

page 10 of 12 ‡ SIGNET 8850-2 Conductivity/Resistivity Transmitter
"- - - -"
Value Must be less
than 3
Value must be greater than 0
"Value must be
400 or less"
Display erratic, shows "0" or
"------" intermittently
"Too much Error
Check ensor"
Display is over range. This may be a
normal condition if your process operates
at/near the limits of the sensor range.
The PPM factor must be a value from
0.00 to 3.00
Custom cell constant cannot be set to 0
Pulse Rate cannot be greater than 400
Aux Power not connected
• Defective or dirty/coated sensor
• Wiring error
• Fluid conductivity too low
• Defective temp element
• Check sensor for correct range.
• Check Decimal setting in OPTIONS menu.
• Check Calibrate menu settings for incompatible
SOURCE and RANGE values.
Set a PPM value less than 3.
Set cell constant to a value greater than 0
set a pulse rate value less than 400
Wire 8850 according to diagram (Section 3.1)
• Clean or replace sensor
• Check and correct wiring
• Replace sensor
Display Condition uggested olutionsPossible Causes
Troubleshooting
If a Current Loop is locked at 3.6 mA, the problem is related to the temperature circuit:
This occurs only if the 8850 detects a resistance from the temperature sensor that is less than 250Ω or greater than 2800Ω.
• Check the sensor wiring for open/short or poor connections on white (TEMP IN) and black (ISO GND)wires.
• The PT1000 temperature device in the sensor is defective.
• The transmitter is defective.
Auxiliary Power (terminals 1 and 2) must ALWAYS be connected for the 8850 to operate.
Technical notes