2. Check the process for cavitation, flashing, or leaks.
3. Monitor the density of your process fluid output under normal process conditions.
4. 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.
10.25 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
Possible causes and recommended actions for excessive (saturated)
drive gain
Table 10-4:
Possible cause Recommended actions
Bent sensor tube Check the pickoff voltages (see Section 10.26). If either of them are close to
zero (but neither is zero), the sensor tubes may be bent. The sensor will
need to be replaced.
Cavitation or flash-
ing; settling of two-
phase or three-phase
fluids
• 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.
Cracked sensor tube Replace the sensor.
Core processor
or module failure
Contact customer support.
Flow rate out of
range
Ensure that the flow rate is within sensor limits.
Incorrect sensor
characterization
Verify the characterization or calibration parameters.
Open drive or pickoff
sensor coil
Contact customer support.
Over-pressurized
tubes
Contact customer support.
Troubleshooting
146 Micro Motion Model 1500 Transmitters with Analog Outputs
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