Emerson Process Management 2400S manual Checking slug flow

Troubleshooting

Table 11-3Process variables problems and remedies continued

Symptom	Cause	Suggested remedy
Inaccurate density reading	Problem with process fluid	• Use standard procedures to check
		quality of process fluid.
	Bad density calibration factors	• Verify characterization. See
		Section 6.2.
	Wiring problem	• Check the sensor circuitry. See
		Section 11.20.
	Bad flowmeter grounding	• See Section 11.7.2.
	Slug flow	• See Section 11.14.
	Sensor cross-talk	• Check environment for sensor with
		similar (±0.5 Hz) tube frequency.
	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.
	RTD failure	• Check for alarm conditions and follow
		troubleshooting procedure for
		indicated alarm.
	Physical characteristics of sensor have	• Check for corrosion, erosion, or tube
	changed	damage. See Section 11.15.
Temperature reading significantly	RTD failure	• Check for alarm conditions and follow
different from process temperature		troubleshooting procedure for
		indicated alarm.
		• Verify “Use external temperature”
		configuration and disable if
		appropriate. See Section 9.3.
Temperature reading slightly different	Sensor leaking heat	• Insulate the sensor.
from process temperature
Unusually high density reading	Plugged flow tube	• Check drive gain and tube frequency.
		Purge the flow tubes.
	Incorrect K2 value	• Verify characterization. See
		Section 6.2.
Unusually low density reading	Slug flow	• See Section 11.14.
	Incorrect K2 value	• Verify characterization. See
		Section 6.2.
Unusually high tube frequency	Sensor erosion	• Contact Micro Motion. See
		Section 11.3.
Unusually low tube frequency	Plugged flow tube, corrosion, or erosion	• Purge the flow tubes.
		• Perform meter verification. See
		Section 11.15.
Unusually low pickoff voltages	Several possible causes	• See Section 11.19.4.
Unusually high drive gain	Several possible causes	• See Section 11.19.3.

11.14Checking slug flow

A slug flow alarm is posted whenever the measured process density is outside the configured slug flow limits (i.e., density is higher or lower than the configured normal range). Slug flow is typically caused by gas in a liquid process or liquid in a gas process. See Section 8.7 for a discussion of slug flow functionality.

Compensation

Measurement Performance

Troubleshooting

Defaults

Configuration and Use Manual 121