PLC-API 5.4.8 FB_CTRL_PI_PID The function block provides a cascaded PI-PID controller in the functional diagram. Internally, this block uses the FB_CTRL_PI, FB_CTRL_LIMITER and FB_CTRL_PID transfer elements. Transfer function of the PI element: Transfer function of the PID element: Functional diagram for the cascaded transfer element: VAR_INPUT VAR_INPUT fSetpointValue : FLOAT; (* setpoint value *) fActualValueOuterLoop : FLOAT; (* actual value from the process to the PI-controller *) fActualValueInnerLoop : FLOAT; (* actual value from the process to the PID- controller *) fPreControl : FLOAT; (* pre control value *) fManSyncValueInnerLoop :
FLOAT; (* input value for the manual mode or the sync request * ) bSyncInnerLoop : BOOL; (* rising edge set the output to the fManSyncValue *) eModeInnerLoop : E_CTRL_MODE; (* sets the mode of the function block *) bHoldInnerLoop : BOOL; (* hold the internal integrator *) fManSyncValueOuterLoop : FLOAT; (* input value for the manual mode or the sync request * TS4100 54 Version: 1.1