Emerson Micro Motion 2500 Configuration And Use Manual page 197

To know whether your drive gain is excessive or erratic, you must collect drive gain data
during the problem condition and compare it to drive gain data from a period of normal
operation.
Excessive (saturated) drive gain
Table 12-4:
drive gain
Possible cause
Bent sensor tube
Cavitation or flash-
ing; settling of two-
phase or three-phase
fluids
Cracked sensor tube
Core processor
or module failure
Flow rate out of
range
Incorrect sensor
characterization
Open drive or pickoff
sensor coil
Over-pressurized
tubes
Plugged sensor tube
Sensor case full
of process fluid
Sensor imbalance
Sensor tubes
not completely full
Two-phase flow
Vibrating element
not free to vibrate
Configuration and Use Manual
Possible causes and recommended actions for excessive (saturated)
Recommended actions
Check the pickoff voltages (see
zero (but neither is zero), the sensor tubes may be bent. The sensor will
need to be replaced.
• Increase the inlet or back pressure at the sensor.
• If a pump is located upstream from the sensor, increase the distance
between the pump and sensor.
• The sensor may need to be reoriented or repositioned. Consult the in-
stallation manual for your sensor.
Replace the sensor.
Contact customer support.
Ensure that the flow rate is within sensor limits.
Verify the characterization or calibration parameters.
Contact customer support.
Contact customer support.
Check the pickoff voltages (see
zero (but neither is zero), plugged tubes may be the source of your prob-
lem. Purge the tubes. In extreme cases, you may need to replace the sen-
sor.
Replace the sensor.
Contact customer support.
Correct process conditions so that the sensor tubes are full.
Check for two-phase flow. See
Ensure that the vibrating element is free to vibrate.
Section 12.29). If either of them are close to
Section 12.29). If either of them are close to
Section 12.27.
Troubleshooting
189