Check The Cutoffs; Check For Two-Phase Flow (Slug Flow); Check The Drive Gain - Emerson Micro Motion 2500 Configuration And Use Manual

Troubleshooting
12.26

Check the cutoffs

If the transmitter cutoffs are configured incorrectly, the transmitter may report zero flow
when flow is present, or very small amounts of flow under no-flow conditions.
There are separate cutoff parameters for mass flow rate, volume flow rate, gas standard
volume flow rate (if applicable), and density. There is an independent cutoff for the mA
Output on your transmitter. The interaction between cutoffs sometimes produces
unexpected results.
Procedure
Verify the configuration of all cutoffs.
Tip
For typical applications, set Mass Flow Cutoff to 0.5% of the nominal flow rate of the attached sensor.
See the sensor specifications for nominal flow rate data.
12.27

Check for two-phase flow (slug flow)

Two-phase flow can cause rapid changes in the drive gain. This can cause a variety of
measurement issues.
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4.
12.28

Check the drive gain

Excessive or erratic drive gain may indicate any of a variety of process conditions or sensor
problems.
188
Check for two-phase flow alerts (e.g., A105).
If the transmitter is not generating two-phase flow alerts, verify that two-phase flow
limits have been set. If limits are set, two-phase flow is not the source of your
problem.
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.
Micro Motion Model 2500 Transmitters with Configurable Input/Outputs