Emerson Process Management 2400S manual Erratic non-zeroflow rate under

Troubleshooting

Table 11-3Process variables problems and remedies continued

Symptom	Cause	Suggested remedy
Erratic non-zero flow rate under	Leaking valve or seal	• Check pipeline.
no-flow conditions
	Slug flow	• See Section 11.14.
	Plugged flow tube	• Check drive gain and tube frequency.
		Purge the flow tubes.
	Incorrect sensor orientation	• Sensor orientation must be
		appropriate to process fluid. See the
		installation manual for your sensor.
	Wiring problem	• Check the sensor circuitry. See
		Section 11.20.
	Vibration in pipeline at rate close to	• Check environment and remove
	sensor tube frequency	source of vibration.
	Damping value too low	• Check configuration. See Section 8.4.
	Mounting stress on sensor	• Check sensor mounting. Ensure:
		- Sensor is not being used to support
		pipe.
		- Sensor is not being used to correct
		pipe misalignment.
		- Sensor is not too heavy for pipe.
	Sensor cross-talk	• Check environment for sensor with
		similar (±0.5 Hz) tube frequency.

Erratic non-zero flow rate when flow is steady

Slug flow	• See Section 11.14.
Damping value too low	• Check configuration. See Section 8.4.
Plugged flow tube	• Check drive gain and tube frequency.
	Purge the flow tubes.
Excessive or erratic drive gain	• See Section 11.19.3.
Output wiring problem	• Verify wiring between transmitter and
	receiving device. See the installation
	manual for your transmitter.

	Problem with receiving device	• Test with another receiving device.
	Wiring problem	• Check the sensor circuitry. See
		Section 11.20.
Inaccurate flow rate or batch total	Bad flow calibration factor	• Verify characterization. See
		Section 6.2.
	Inappropriate measurement unit	• Check configuration. See
		Section 11.16.
	Bad sensor zero	• Rezero the flowmeter or restore the
		factory zero or prior zero. See
		Section 10.5.
	Bad density calibration factors	• Verify characterization. See
		Section 6.2.
	Bad flowmeter grounding	• See Section 11.7.2.
	Slug flow	• See Section 11.14.
	Wiring problem	• Check the sensor circuitry. See
		Section 11.20.

120 Micro Motion® Model 2400S Transmitters for DeviceNet™