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

Troubleshooting
4.
9.9

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 9-1:
gain
Possible cause
Bent sensor tube
Cracked sensor tube
Core processor
or module failure
Flow rate out of
range
Open drive or pickoff
sensor coil
Over-pressurized
tubes
Plugged sensor tube
Sensor case full
of process fluid
Sensor imbalance
Sensor tubes
not completely full
Two-phase flow
122
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) drive
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.
Replace the sensor.
Contact customer support.
Ensure that the flow rate is within sensor limits.
Contact customer support.
Contact customer support.
Check the pickoff voltages (see
zero (but neither is zero), plugged tubes may be the source of your prob-
lem. Purge the tubes. In extreme cases, you may need to replace the sen-
sor.
Replace the sensor.
Contact customer support.
Correct process conditions so that the sensor tubes are full.
Check for two-phase flow. See
Micro Motion Model 2700 Transmitters with FOUNDATION Fieldbus
Section 9.10). If either of them are close to
Section 9.10). If either of them are close to
Section 9.8.