Emerson 5081-T Troubleshooting When a Fault or Warning Message is Showing, Temp HI, Temp LO

MODEL 5081-T	SECTION 10.0
	DIAGNOSIS AND TROUBLESHOOTING

10.8TROUBLESHOOTING WHEN A FAULT OR WARNING MESSAGE IS SHOWING

Message	Explanation	See Section
OuEr rAnGE	Over range, measurement exceeds display limit	10.8.1
SEnSor FAIL	Bad sensor, sensor current is a large negative number	10.8.2
CAL Error	Calibration error, sensitivity (nA/ppm) is too high or too low	10.8.3
nEEd 0 CAL	Sensor needs re-zeroing, reading is too negative	10.8.4
rtd FAIL	Bad temperature reading	10.8.5
TEMP HI	Temperature reading exceeds 275°C when auto temp is selected	10.8.5
TEMP LO	Temperature reading is less than -25°C when auto temp is selected	10.8.5
SenSE OPEn	Sense line is not connected	10.8.6
OFFSEt Err	Zero offset during standardization exceeds programmed limit	10.8.7
FACt FAIL	Unit has not been factory-calibrated	10.8.8
CPU FAIL	Internal CPU tests have failed	10.8.9
ROM FAIL	Internal memory has failed	10.8.9
AdC Error	Analog to digital conversion failed	10.8.10

10.8.1 OuEr rAnGE and AMP FAIL.

These error messages appear if the sensor current is too high. Normally, excessive sensor current implies that the sensor is miswired or the sensor has failed.

1.Verify that wiring is correct and connections are tight. Be sure to check connections at the junction box if one is being used. See Section 3.0.

2.Replace the sensor membrane and electrolyte solution and clean the cathode if necessary. See the sensor instruction sheet for details.

3.Replace the sensor.

10.8.2 SEnSor FAIL.

Bad sensor means that the sensor current is a large negative number.

1.SEnSor FAIL may appear for a while when the sensor is first placed in service. Observe the sensor current (go to SEnSor Cur under the diagnostic menu). If the sensor current 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 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.

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