Emerson Micro Motion 3711 Configuration And Use Manual page 186

Maintenance and Troubleshooting
Table 15-3 Process variables problems and possible remedies continued
Symptom
Inaccurate flow rate
Inaccurate density reading
Temperature reading significantly
different from process temperature
Temperature reading slightly different
from process temperature
Unusually high density reading
Unusually low density reading
Unusually high tube frequency
Unusually low tube frequency
Unusually low pickoff voltages
Unusually high drive gain
178
Cause
Bad flow calibration factor
Bad sensor zero
Bad density calibration factors
Bad meter grounding
Slug flow
Wiring problem
Problem with process fluid
Bad density calibration factors
Wiring problem
Bad meter grounding
Slug flow
Sensor cross-talk
Plugged flow tube
RTD failure
Temperature incorrectly configured
Temperature calibration required
Plugged flow tube
Incorrect K2 value
Slug flow
Incorrect K2 value
Sensor erosion
Plugged flow tube
Several possible causes
Several possible causes
Possible remedy
Verify characterization. See
Section 15.13.
Rezero the meter. See Section 5.6.
Verify characterization. See
Section 15.13.
See Section 15.15.3.
See Section 15.12.
Verify all sensor-to-transmitter wiring
and ensure the wires are making good
contact.
Use standard procedures to check
quality of process fluid.
Verify characterization. See
Section 15.13.
Verify all sensor-to-transmitter wiring
and ensure the wires are making good
contact.
See Section 15.15.3.
See Section 15.12.
Check environment for sensor with
similar (±0.5 Hz) tube frequency.
Check drive gain and tube frequency.
Purge the flow tubes.
Check for alarm conditions and follow
troubleshooting procedure for indicated
alarm.
Verify temperature source
configuration. See Section 5.4.3.
Contact Micro Motion. See Section 1.8.
Check drive gain and tube frequency.
Purge the flow tubes.
Verify characterization. See
Section 15.13.
See Section 15.12.
Verify characterization. See
Section 15.13.
Contact Micro Motion. See Section 1.8.
Purge the flow tubes.
See Section 15.16.2
See Section 15.16.2.
®
Micro Motion Model 3711 Gas Flow Computers
.