PLC-API eState : State of the function block. eErrorId : Supplies the error number [ } 16] when the bError output is set. bError : Becomes TRUE, as soon as an error occurs. VAR_IN_OUT VAR_IN_OUT stParams : ST_CTRL_PI_PARAMS; END_VAR stParams : Parameter structure of the PI element. This consists of the following elements: TYPE ST_CTRL_PI_PARAMS : STRUCT tCtrlCycleTime : TIME := T#0ms; (* controller cycle time [TIME] *) tTaskCycleTime : TIME := T#0ms; (* task cycle time [TIME] *) tTn : TIME := T#0ms; (* integral action time Tn *) fKp : FLOAT := 0; (* proportional gain *) fOutMaxLimit : FLOAT := 1E38; (* maximum output limit *) fOutMinLimit :
FLOAT := -1E38; (* minimum output limit *) bARWOnIPartOnly : BOOL := FALSE; (* FALSE: Hold the I-part if the entire control output reaches a limit. *) (* TRUE: Hold the I-part if only the I-part reaches a limit. *) END_STRUCT END_TYPE tCtrlCycleTime : Cycle time with which the control loop is processed. This must be greater than or equal to the TaskCycleTime. The function block uses this input value to calculate internally whether the state and the output values have to be updated in the current cycle. tTaskCycleTime : Cycle time with which the function block is called. If the function block is called in every cycle this corresponds to the task cycle time of the calling task. tTn :
Integral action time fKp : Controller amplification / transfer coefficient fOutMaxLimit : Upper limit at which integration is halted and to which the output is limited (ARW measure). Reaching this limit is indicated by a TRUE at the bARWActive output. fOutMinLimit : Lower limit at which integration is halted and to which the output is limited (ARW measure). Reaching this limit is indicated by a TRUE at the bARWActive output. bARWOnIPartOnly : If this parameter is FALSE (the default setting), the integration of the I-component is halted if the complete controller output reaches the upper or lower limit.
If it is TRUE, the integration is halted if the I-component (the output of the integrator) reaches some limit. (Cf. functional diagram) Requirements TS4100 53 Version: 1.1 Development Environment Target System PLC libraries to include TwinCAT v2.8 PC (i386) TcControllerToolbox.lib TwinCAT v2.9 from Build 947 BC [} 10] TcControllerToolbox.lb6 TwinCAT v2.9 from Build 956 BX [} 10] TcControllerToolbox.lbx