Emerson Micro Motion 2500, Configuration And Use Manual

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Procedure
1. 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/cm ³ , even if you configured another
unit for density measurement.
The default value for Two-Phase Flow Low Limit is 0.0 g/cm ³ . The range is 0.0 to
10.0 g/cm ³ .
2. 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/cm ³ , even if you configured another
unit for density measurement.
The default value for Two-Phase Flow High Limit is 5.0 g/cm ³ . The range is 0.0 to
10.0 g/cm ³ .
3. 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.
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:
• 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.
If the two-phase flow condition clears before Two-Phase Flow Timeout expires:
• Outputs that represent flow rate revert to reporting actual flow.
Configure process measurement
40 Micro Motion Model 2500 Transmitters with Configurable Input/Outputs