Use MMC Function Block for Splitter Control

The following example describes using an MMC function block to control a splitter. Refer to the MMC Function Block Splitter Example Configuration in Module Multivariable Control ( MMC).
Item
Description
PV1
Top composition (more important)
PV2
Bottom composition (less important)
Active 1st CV for PV1
CV1 (reflux ratio)
Active 2nd CV for PV1
CV3 (pressure setpoint)
Active 3rd CV for PV1
CV2 (steam (flow)
Active 1st CV for PV2
CV2
Active 2nd CV for PV2
CV3
Active 3rd CV for PV2
CV1
TargetCV
CV3 (pressure should be held constant if possible)
CV3Target
60% (of pressure range)
The MMC calculates CV1, CV2, and CV3 so that the control goals are accomplished in the following order of importance:
  1. Control PV1 to SP1 (PV1 is always considered more important than PV2)
  2. Control PV2 to SP2
  3. Control CV3 to its target value
CV1 is selected as the most active control for PV1 and CV2 as the most active for PV2. If either CV1 or CV2 saturates or is put in Manual mode, the control variable will use CV3 to maintain PV1 and PV2 at the setpoints.
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