Emerson Micro Motion LNG Series, Configuration And Use Manual

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Possible causes and recommended actions for excessive (saturated)
drive gain
(continued)
Table 10-5:
Possible cause Recommended actions
Bent sensor tube Check the pickoff voltages (see Section 10.11 ). If either of them
are close to zero (but neither is zero), the sensor tubes may be
bent. The sensor will need to be replaced.
Cracked sensor tube Replace the sensor.
Sensor imbalance Contact Micro Motion.
Vibrating element not free to
vibrate Ensure that the vibrating element is free to vibrate.
Open drive or left pickoff sen-
sor coil Contact Micro Motion.
Flow rate out of range Ensure that the flow rate is within sensor limits.
Incorrect sensor characteriza-
tion Verify the characterization or calibration parameters.
Erratic drive gain
Possible causes and recommended actions for erratic drive gain Table 10-6:
Possible cause Recommended actions
Foreign material caught in sen-
sor tubes • Purge the sensor tubes.
• Replace the sensor.
10.10.1 Collect drive gain data
Drive gain data can be used to diagnose a variety of process and equipment conditions.
Collect drive gain data from a period of normal operation, and use this data as a baseline
for troubleshooting.
Procedure
1. Navigate to the drive gain data.
2. Observe and record drive gain data over an appropriate period of time, under a
variety of process conditions.
10.11 Check the pickoff voltage
If the pickoff voltage readings are unusually low, you may have any of a variety of process
or equipment problems.
Troubleshooting
Configuration and Use Manual 81