CV Control objective values don’t match current value
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Last Updated:
28-Sep-2021
Last Updated:
28-Sep-2021
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Article ID:
000099013
Article ID:
000099013
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Problem Description
CV Control objective values don’t match current value
Solution
The value “from” in the CV Controller objectives is the open loop prediction at the time of steady state. The steady state solver is moving the CV from its predicted open loop value at steady state to its closed loop value, not from its current measurement to its steady state or from its previous steady state to its new steady state.
If the predictions have been initialized, then the measurement and open loop prediction at steady state will be the same and the controller objective will reflect that.
The "from" value for CVs is stored on the AW_PSSDEP entry on the IP.21 database. AW_PSSDEP is an approximation of CV open loop prediction, so you will see a slight value difference if you compare it with the results from the controller print file.
This behavior is also present in the what-if simulation: https://esupport.aspentech.com/S_Article?id=000075567
Keywords
Controller Objectives
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