Configure process measurement
2.
Set
Slug High Limit
to the highest density value that is considered normal in your process.
Tip
To reduce the occurrence of slug flow alarms that are not significant to your process, set
Slug High
Limit
slightly above your expected highest process density.
Values above this will cause the transmitter to perform the configured slug flow action. Typically,
this value is the highest density value in the normal range of your process.
You must enter
Slug High Limit
in g/cm
3
, even if another unit has been configured for density
measurement.
The default value for
Slug High Limit
is 5.0 g/cm
3
. The range is 0.0 g/cm
3
to 10.0 g/cm
3
.
3.
Set
Slug Duration
to the number of seconds that the transmitter will wait for a slug flow condition to
clear before performing the configured slug flow action.
The default value for
Slug Duration
is 0.0 seconds. The range is 0.0 seconds to 60.0 seconds.
Slug flow detection and reporting
Slug flow is typically used as an indicator of two-phase flow (gas in a liquid process or liquid in a gas
process). Two-phase flow can cause a variety of process control issues. By configuring the slug flow
parameters appropriately for your application, you can detect process conditions that require correction.
Tip
To decrease the occurrence of slug flow alarms, lower
Slug Low Limit
or raise
Slug High Limit
.
A condition of slug flow occurs whenever the measured density goes below
Slug Low Limit
or above
Slug High Limit
. If this occurs:
• A slug flow alarm is posted to the active alarm log.
• All outputs that are configured to represent flow rate hold their last “pre-slug flow” value for the
configured
Slug Duration
.
If the slug flow condition clears before
Slug Duration
expires:
• Outputs that represent flow rate revert to reporting actual flow.
• The slug flow alarm is deactivated, but remains in the active alarm log until it is acknowledged.
If the slug flow condition does not clear before
Slug Duration
expires, outputs that represent flow rate
report a flow rate of 0.
If
Slug Duration
is set to 0.0 seconds, outputs that represent flow rate will report a flow rate of 0 as soon as
slug flow is detected.
86
Micro Motion 9739 MVD Transmitters
