Emerson MMI-20011276 Manuel D’Utilisation
12
Micro Motion
®
Series 3000 MVD Transmitters
NOC Overview
To determine the value to use for the drive gain threshold, observe drive gain values for this system
during various flow conditions.
during various flow conditions.
The NOC application can perform several different actions if transient bubbles are detected:
•
Substituting a previously measured density value for the measured density value in NOC
calculations (the Hold Last Value option)
calculations (the Hold Last Value option)
•
Stopping the well test (if a well test is in progress)
•
Posting an alarm
Additionally, you can configure a discrete output to report TBR status (see Section 5.3).
The Hold Last Value option directs the NOC application to retrieve the measured density value from
an earlier point in the process. The earlier point is identified by the configured Time Period (see
Figure 2-7). The density values from a three-second period around this point are averaged, and this
retrieved density average is then used in NOC calculations. Figure 2-8 shows how the Hold Last Value
action affects the density measurement.
an earlier point in the process. The earlier point is identified by the configured Time Period (see
Figure 2-7). The density values from a three-second period around this point are averaged, and this
retrieved density average is then used in NOC calculations. Figure 2-8 shows how the Hold Last Value
action affects the density measurement.
Note: If the Time Period happens to fall into a previous transient bubble interval, the NOC
application automatically extends the lookback interval as required to retrieve an averaged value
from measured density values rather than substituted density values.
application automatically extends the lookback interval as required to retrieve an averaged value
from measured density values rather than substituted density values.
Figure 2-7
Hold Last Value option
Density (measured)
Drive gain (actual)
Drive gain setpoint
Time Period
(seconds)
Density values
(retrieved and averaged)