Drive Gain Problems; Low Pickoff Voltage - Emerson Micro Motion 2400S Configuration And Use Manual

Troubleshooting
11.19.3

Drive gain problems

Problems with drive gain can appear in several different forms:
• Saturated or excessive (near 100%) drive gain
• Erratic drive gain (e.g., rapid shifting from positive to negative)
• Negative drive gain
See Table 11-6 for a list of possible problems and remedies.
Table 11-6 Drive gain problems, causes, and remedies
Cause
Excessive slug flow
Cavitation or flashing
Plugged flow tube
Mechanical binding of sensor tubes
Incorrect sensor type configured
Open drive or left pickoff sensor coil
Drive board or module failure, cracked flow tube,
or sensor imbalance
11.19.4

Low pickoff voltage

Low pickoff voltage can be caused by several problems. See Table 11-7.
Table 11-7 Low pickoff voltage causes and remedies
Cause
Slug flow
No tube vibration in sensor
Moisture in the sensor electronics
Damaged sensor
124
Possible remedy
• See Section 11.14.
• Increase inlet or back pressure at the sensor.
• If a pump is located upstream from the sensor, increase the distance
between the pump and sensor.
• Purge the flow tubes.
• Ensure sensor tubes are free to vibrate. Possible problems include:
- Pipe stress. Check for pipe stress and eliminate if present.
- Lateral tube shift due to hammer effect. If this is a possibility,
contact Micro Motion. See Section 11.3.
- Warped tubes caused by overpressurization. If this is a possibility,
contact Micro Motion.
• Verify sensor type configuration, then verify sensor characterization.
See Section 6.2.
• Contact Micro Motion. See Section 11.3.
• Contact Micro Motion. See Section 11.3.
Possible remedy
• See Section 11.14.
• Check for plugging.
• Eliminate the moisture in the sensor electronics.
• Ensure sensor is free to vibrate (no mechanical binding). Possible
problems include:
- Pipe stress. Check for pipe stress and eliminate if present.
- Lateral tube shift due to hammer effect. If this is a possibility,
contact Micro Motion. See Section 11.3.
- Warped tubes caused by overpressurization. If this is a possibility,
contact Micro Motion.
• Test sensor circuitry. See Section 11.20.
• Contact Micro Motion.
Micro Motion
®
Model 2400S Transmitters for DeviceNet
™