Check The Drive Gain - Emerson Micro Motion 2700 Configuration And Use Manual

Troubleshooting
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3.
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10.26

Check the drive gain

Excessive or erratic drive gain may indicate any of a variety of process conditions or sensor
problems.
To know whether your drive gain is excessive or erratic, you must collect drive gain data
during the problem condition and compare it to drive gain data from a period of normal
operation.
Excessive (saturated) drive gain
Table 10-4:
drive gain
Possible cause
Bent sensor tube
Cavitation or flash-
ing; settling of two-
phase or three-phase
fluids
Cracked sensor tube
Core processor
or module failure
Flow rate out of
range
Incorrect sensor
characterization
Open drive or pickoff
sensor coil
Over-pressurized
tubes
200
Check the process for cavitation, flashing, or leaks.
Monitor the density of your process fluid output under normal process conditions.
Check the settings of Two-Phase Flow Low Limit, Two-Phase Flow High Limit, and
Two-Phase Flow Timeout.
Tip
You can reduce the occurrence of two-phase flow alerts by setting Two-Phase Flow Low Limit
to a lower value, Two-Phase Flow High Limit to a higher value, or Two-Phase Flow Timeout to
a higher value. Micro Motion recommends leaving the Two-Phase Flow High Limit at the
default value.
Possible causes and recommended actions for excessive (saturated)
Recommended actions
Check the pickoff voltages (see
zero (but neither is zero), the sensor tubes may be bent. The sensor will
need to be replaced.
• 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 or repositioned. Consult the in-
stallation manual for your sensor.
Replace the sensor.
Contact customer support.
Ensure that the flow rate is within sensor limits.
Verify the characterization or calibration parameters.
Contact customer support.
Contact customer support.
Micro Motion Model 2700 Transmitters with Intrinsically Safe Outputs
Section 10.27). If either of them are close to