Check The Pickoff Voltage - Emerson Micro Motion SGM Configuration And Use Manual

Configuration and Use Manual
MMI-20020954
Erratic drive gain
Table 14-7: Possible causes and recommended actions for erratic drive gain
Possible cause
Foreign material caught on vibrating
element or in sensor
14.24.2 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.

14.25 Check the pickoff voltage

If the pickoff voltage readings are unusually low, you may have any of a variety of process or equipment
problems.
Typical pickoff voltage readings go from 0.005 to 0.01 volts.
To know whether your pickoff voltage is unusually low, you must collect pickoff voltage data during the
problem condition and compare it to pickoff voltage data from a period of normal operation.
Table 14-8: Possible causes and recommended actions for low pickoff voltage
Possible cause
Moisture, settling of two-phase or three-phase fluids
The vibrating element is not vibrating
Moisture in the sensor electronics
The sensor is damaged, or sensor magnets may have
become demagnetized
Configuration and Use Manual
Recommended actions
Ensure that the vibrating element is free to vibrate.
Recommended actions
• Increase the inlet or back pressure at the meter.
• If a pump is located upstream from the meter, increase
the distance between the pump and meter.
• Check for moisture inside the measurement chamber
or the reference chamber.
• Check for plugging or deposition.
• Ensure that the vibrating element is free to vibrate (no
mechanical binding).
Eliminate the moisture in the sensor electronics.
Replace the sensor.
Troubleshooting
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