Emerson Micro Motion 1600 - 16.14 Check the drive gain; 16.15 Check for internal electrical problems

16.14 Check the drive gain
Excessive or erratic drive gain may indicate any of a variety of process conditions or sensor problems.
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 16-3: Possible causes and recommended actions for excessive (saturated) drive gain
Possible cause Recommended actions
Bent sensor tube Check the pickoff voltages (see Check the pickoff voltage). 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.
Flow rate out of range Verify calibration factors are correct.
Open drive or pickoff
sensor coil
Contact customer support.
Over-pressurized tubes Replace the sensor.
Plugged sensor tube A dull, audible hum, and unusually high sensor vibration is usually accompanied by high,
even saturated, drive gain. Check the pickoff voltages (see Check the pickoff voltage). If either
of them are close to zero (but neither is zero), plugged tubes may be the source of your
problem. Purge the tubes. In extreme cases, you may need to replace the sensor.
Sensor case full of process
fluid
Replace the sensor.
Sensor imbalance Contact customer support.
Sensor tubes not
completely full
Correct process conditions so that the sensor tubes are full.
Two-phase flow Check for two-phase flow. See Check for two-phase flow (slug flow).
Vibrating element not free
to vibrate
Ensure that the vibrating element is free to vibrate.
Erratic drive gain
Table 16-4: Possible causes and recommended actions for erratic drive gain
Possible cause Recommended actions
Foreign material caught in sensor
tubes
• Purge the sensor tubes.
• Replace the sensor.
Internal sensor damage Replace the sensor.
16.15 Check for internal electrical problems
Shorts between sensor terminals or between the sensor terminals and the sensor case can cause the sensor to
report false or erroneous readings.
Possible cause
Recommended action
Moisture inside the sensor junction box Ensure that the junction box is dry and no corrosion is
present.
Liquid or moisture inside the sensor case Contact customer support.
Configuration and Use Manual Troubleshooting
MS-00809-0200-1600 May2024
Configuration and Use Manual 207