Emerson Micro Motion 1500 Configuration And Use Manual page 46

Configure process measurement
Procedure
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Detecting and reporting two-phase flow
Two-phase flow (gas in a liquid process or liquid in a gas process) can cause a variety of
process control issues. By configuring the two-phase flow parameters appropriately for
your application, you can detect process conditions that require correction.
Micro Motion recommends leaving Two-Phase Flow High Limit at the default value.
A two-phase flow condition occurs whenever the measured density goes below Two-Phase
Flow Low Limit or above Two-Phase Flow High Limit. If this occurs:
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If the two-phase flow condition clears before Two-Phase Flow Timeout expires:
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Set Two-Phase Flow Low Limit to the lowest density value that is considered normal
in your process.
Values below this will cause the transmitter to post Alert A105 (Two-Phase Flow).
Tip
Gas entrainment can cause your process density to drop temporarily. To reduce the
occurrence of two-phase flow alerts that are not significant to your process, set Two-Phase
Flow Low Limit slightly below your expected lowest process density.
You must enter Two-Phase Flow Low Limit in g/cm³, even if you configured another
unit for density measurement.
The default value for Two-Phase Flow Low Limit is 0.0 g/cm³. The range is 0.0 to
10.0 g/cm³.
Set Two-Phase Flow High Limit to the highest density value that is considered
normal in your process.
Micro Motion recommends leaving Two-Phase Flow High Limit at the default value.
Values above this will cause the transmitter to post Alert A105 (Two-Phase Flow).
You must enter Two-Phase Flow High Limit in g/cm³, even if you configured another
unit for density measurement.
The default value for Two-Phase Flow High Limit is 5.0 g/cm³. The range is 0.0 to
10.0 g/cm³.
Set Two-Phase Flow Timeout to the number of seconds that the transmitter will wait
for a two-phase flow condition to clear before posting the alert.
The default value for Two-Phase Flow Timeout is 0.0 seconds, meaning that the alert
will be posted immediately. The range is 0.0 to 60.0 seconds.
A two-phase flow alert is posted to the active alert log.
All outputs that are configured to represent flow rate hold their last pre‐alert value
for the number of seconds configured in Two-Phase Flow Timeout.
Outputs that represent flow rate revert to reporting actual flow.
Micro Motion Model 1500 Transmitters with Analog Outputs