Process Control Instructions
86 Rockwell Automation Publication 1756-RM006K-EN-P - November 2018
Function Block
Structured Text
PrimaryLoop.PV := Local:1:I.CH0Data;
PrimaryLoop.CVInitReq := SecondaryLoop.InitPrimary;
PrimaryLoop.CVInitValue := SecondaryLoop.SP;
PrimaryLoop.WindupHIn := SecondaryLoop.WindupHOut;
PrimaryLoop.WindupLIn := SecondaryLoop.WindupLOut;
PIDE(PrimaryLoop);
SecondaryLoop.PV := Local:1:I.Ch1Data;
SecondaryLoop.SPCascade := PrimaryLoop.CVEU;
PIDE(SecondaryLoop);
Local:2:O.Ch0Data:= SecondaryLoop.CVEU;
For a cascaded pair of loops to work correctly, the secondary loop must have a
faster process response than the primary loop. This is because the secondary loop’s
process must be able to compensate for any upsets before these upsets affect the
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