Chapter 7. PID Built-In Function BlockGFK-2950C February 2018 3457.1.2 Operands for FBD Version of PID Function BlockParameter Description Allowed Types Allowed Operands OptionalControlStructureVariableInstance Variable name of the PIDParameter Block array, which containsuser-configurable and internalparameters, described in ReferenceArray for the PID Function. Uses 40words that cannot be shared.WORD R, L, P, Wand symbolicNoFunctionblock solveorder – FBDversionCalculated by the FBD editor. Can bechanged by the user.NA NA NoSP The control loop or process set point.Set using process variable counts, thePID function adjusts the outputcontrol variable so that the processvariable matches the set point (zeroerror).INT, BOOL array oflength 16 or more,ConstantAll except S, SA, SB,and SCNoPV Process Variable input from theprocess being controlled. Often a %AIinput.INT, BOOL array oflength 16 or moreAll except S, SA, SB,SC and constantNoMAN When energized to 1 (through acontact), the PID function block is inmanual mode. If this input is 0, thePID block is in automatic mode.BOOL, Power Flow All NoUP If energized along with MAN,increases the control variable by 1 CVcount per solution of the PID functionblock.BOOL, Power Flow All NoDN If energized along with MAN,decreases the control variable by 1CV count per solution of the PIDfunction block.BOOL, Power Flow All NoCV The control variable output to theprocess. Often a %AQ output.INT, BOOL array oflength 16 or moreAll except %S andconstantNo
