FB_BasicPID

Transfer function:

Action diagram:

VAR_INPUT

VAR_INPUT
    fSetpointValue : LREAL; (* setpoint value *)
    fActualValue   : LREAL; (* actual value *)
    bReset         : BOOL;
    fCtrlCycleTime : LREAL; (* controller cycle time in seconds [s] *)
    fKp            : LREAL; (* proportional gain Kp (P) *)
    fTn            : LREAL; (* integral gain Tn (I) [s] *)
    fTv            : LREAL; (* derivative gain Tv (D-T1) [s] *)
    fTd            : LREAL; (* derivative damping time Td (D-T1) [s] *)
END_VAR

fSetpointValue : Set value of the controlled variable.

fActualValue : Actual value of the controlled variable.

bReset: TRUE at this input resets the internal state variables and the controller output.

fCtrlCycleTime: Cycle time with which the function block is called and with which the control loop is processed [s].

Here you must specify the cycle time of the PLC task, if the block is to be called in each PLC cycle,

otherwise the required multiple of the PLC task cycle time.

fKp : Controller amplification / controller coefficient

fTn : Integral action time [s]

fTv : Rate time [s]

fTd : Damping time [s]

VAR_OUTPUT

VAR_OUTPUT
    fCtrlOutput  : LREAL;
    nErrorStatus : UINT
END_VAR

fCtrlOutput : Output of the PID-element.

nErrorStatus: Indicates the error number in the event of an error (nErrorStatus <> 0).

Error Codes:

Requirements