Emerson MMI-20019043 Manuel D’Utilisation

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Possible causes and recommended actions for erratic drive gain
(continued)
Table 12-9:   
Possible cause
Recommended actions
Polarity of pick-off reversed or polarity of drive reversed Contact Micro Motion.
Slug flow
Foreign material caught in flow tubes
Purge the flow tubes.
Replace the sensor.
12.26.1
Collect drive gain data
Drive gain data can be used to diagnose a variety of process and equipment conditions.
Collect drive gain data from a period of normal operation, and use this data as a baseline
for troubleshooting.
Procedure
1.
Navigate to the drive gain data.
2.
Observe and record drive gain data over an appropriate period of time, under a
variety of process conditions.
12.27
Check the pickoff voltage
If the pickoff voltage readings are unusually low, you may have any of a variety of process
or equipment problems.
To know whether your pickoff voltage is unusually low, you must collect pickoff voltage
data during the problem condition and compare it to pickoff voltage data from a period of
normal operation.
Possible causes and recommended actions for low pickoff voltage
Table 12-10:   
Possible cause
Recommended actions
Air entrainment
Increase the inlet or back pressure at the sensor.
If a pump is located upstream from the sensor, increase the
distance between the pump and sensor.
The sensor may need to be reoriented. Consult the installation
manual for your sensor for recommended orientations.
Faulty wiring runs between
the sensor and transmitter
Verify wiring between sensor and transmitter.
Process flow rate beyond the
limits of the sensor
Verify that the process flow rate is not out of range of the sensor.
Slug flow
.
Troubleshooting
240
Micro Motion
®
 Model 2700 Transmitters with Analog Outputs