SEnSor FAIL may appear for a while when the sensor is first placed in service.
Procedure
1. Observe the sensor current (go to SEnSor Cur under the Diagnostic menu).
If the sensor is moving in the positive direction, there is probably nothing wrong,
and the error message should soon disappear.
2. Verify that wiring is correct. Pay particular attention to the anode and cathode
connections.
3. Verify that the transmitter is configured for the correct measurement.
Configuring the measurement sets (among other things) the polarizing voltage.
Applying the wrong polarizing voltage to the sensor can cause a negative current.
4. Replace the sensor membrane and electrolyte solution and clean the cathode if
necessary.
See the sensor instruction sheet for details.
5. Replace the sensor.
CAL Error
At the end of the calibration step, the transmitter calculates the sensitivity in nA/ppm. If
the sensitivity is outside the range normally expected, the transmitter displays the CAL
Error message, and the transmitter does not update the calibration. For assistance, refer to
the troubleshooting section specific to the sensor.
nEEd 0 CAL
nEEd 0 CAL means that the concentration of the analyte is too negative.
1. Check the zero current (go to 0 CurrEnt under the Diagnostic menu).
If the zero current is appreciably greater than the measurement current, the nEEd 0
CAL warning appears.
2. Verify that the zero current is close to the value given in the calibration section for
the analyte being determined.
3. Rezero the sensor.
Refer to the calibration and troubleshooting sections for the sensor for more
information.
rtd FAIL, TEMP HI, and TEMP LO
These messages usually mean that the RTD is open or shorted or there is an open or short
in the connecting wiring.
1. Verify all wiring connections, including wiring in a junction box if one is being used.
2. Disconnect the RTD IN, RTD SENSE, and RTD RETURN leads or the thermistor leads
at the transmitter.
Be sure to note the color of the wire and where it was attached.
Diagnostics and troubleshooting
Instruction Manual 89
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