Emerson 2200S User Manual

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Low pickoff voltage can be caused by several problems. See Table 10-6.

Problems with sensor circuitry can cause several alarms, including sensor failure and a variety of 
out-of-range conditions. Testing involves:

•

Inspecting the cable that connects the transmitter to the sensor

•

Measuring the resistances of the sensor's pin pairs and RTDs

•

Ensuring that the circuits are not shorted to each other or to the sensor case

Excessive slug flow

• See Section 10.17.

Entrained air

• Correct the process.

Cavitation or flashing

• 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.

Plugged flow tube

• Purge the flow tubes.

Mechanical binding of sensor 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.

- Warped tubes caused by overpressurization. If this is a possibility, 

contact Micro Motion.

Incorrect sensor type configured

• Verify sensor type configuration, then verify sensor characterization. 

Open drive or left pickoff sensor coil

• Contact Micro Motion. 

Drive board or module failure, cracked flow tube, 
or sensor imbalance

• Contact Micro Motion. 

Slug flow

• See Section 10.17.

No tube vibration in sensor

• Check for plugging.

Moisture in the sensor electronics

• Eliminate the moisture in the sensor electronics.

Damaged sensor

• 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.

- Warped tubes caused by overpressurization. If this is a 

possibility, contact Micro Motion.

• Test sensor circuitry. See Section 10.24.
• Contact Micro Motion.