10
8850-2 Conductivity/Resistivity Transmitter
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 250
Ω
or greater than 2800
Ω
.
• 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
Display Condition
Possible Causes
Suggested Solutions
"- - - -"
Display is out of range. This may be a normal
condition if your process operates at or near
the limits of the electrode range.
• Check sensor for correct range.
• Check Decimal setting in OPTIONS menu.
• Check Calibrate menu settings for incompatible
SOURCE and RANGE values.
"Value must be
less than 3"
The PPM factor must be a value from
0.00 to 3.00.
Set a PPM value less than 3.
Value must be greater than 0
Custom cell constant cannot be set to 0
Set cell constant to a value greater than 0
"Value must be
400 or less"
Pulse Rate cannot be greater than 400.
Set a pulse rate value less than 400.
Display erratic,
shows "0" or "------"
intermittently
Aux Power not connected.
Connect Aux. Power.
See sections 3.1 and 3.2 for wiring information.
"Too much Error
Check Sensor"
• Defective or dirty/coated sensor.
• Wiring error.
• Fluid conductivity too low.
• Defective temp element.
• Clean or replace sensor.
• Check and correct wiring.
• Replace sensor.
