Configuration and Use Manual
00809-0100-1600
Troubleshooting
November 2022
Excessive (saturated) drive gain
Table 17-5: Possible causes and recommended actions for excessive (saturated) drive gain
Possible cause
Bent sensor tube
Cracked sensor tube
Flow rate out of range
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
Recommended actions
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.
Replace the sensor.
Ensure that the flow rate is within sensor limits.
Contact customer support.
Contact customer support.
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.
Replace the sensor.
Contact customer support.
Correct process conditions so that the sensor tubes are full.
Check for two-phase flow. See Check for two-phase flow (slug flow)
.
Ensure that the vibrating element is free to vibrate.
Erratic drive gain
Table 17-6: Possible causes and recommended actions for erratic drive gain
Possible cause
Foreign material caught in sensor tubes
Recommended actions
• Purge the sensor tubes.
• Replace the sensor.
17.16 Check for internal electrical problems
Shorts between sensor terminals or between the sensor terminals and the sensor case can cause the sensor to stop working.
Possible cause
Moisture inside the sensor junction box
Liquid or moisture inside the sensor case
Internally shorted feedthrough
Faulty cable
Recommended action
Ensure that the junction box is dry and no corrosion is present.
Contact customer support.
Contact customer support.
Replace the cable.
Configuration and Use Manual 207
