The transmitter can use line density data to detect two-phase flow (gas in a liquid process or liquid in a gas
process). The density limits are user-specified. When two-phase flow is detected, an alert is posted.
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 a Process Aberration alert.
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.
• Default: 0 g/cm³
• Range: 0 g/cm³ to the sensor limit
2. Set Two-Phase Flow High Limit to the highest density value that is considered normal in your process.
Values above this will cause the transmitter to post a Process Aberration alert.
Tip
To reduce the occurrence of two-phase flow alerts that are not significant to your process, set Two-
Phase Flow High Limit slightly above your expected highest process density.
You must enter Two-Phase Flow High Limit in g/cm³, even if you configured another unit for density
measurement.
• Default: 5 g/cm³
• Range: 5 g/cm³ to the sensor limit
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.
• Default: 0 seconds, meaning that the alert will be posted immediately
• Range: 0 to 60 seconds
6.2.2 Detect two-phase flow using sensor diagnostics
Display
Menu > Configuration > Inputs/Outputs > Channel x > I/O Settings > Source
ProLink III Device Tools > Configuration > I/O > Outputs > mA Output x
Field Communicator Configure > Manual Setup > Inputs/Outputs > Channel x > mA Output x > mAOxSource
The transmitter always monitors sensor diagnostics and applies a two-phase flow algorithm. You can assign
an mA Output to report the results of this calculation: single-phase flow, moderate two-phase flow, or severe
two-phase flow.
Procedure
Set mA Output Source to Two-Phase Flow Detection.
Configure advanced options for process measurement Configuration and Use Manual
March 2019 MMI-20025166
106 Micro Motion Model 5700 Transmitters with Configurable Outputs
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