FB_CTRL_PT2oscillation

Transfer function:

Step response:

VAR_INPUT

VAR_INPUT
    fIn         : FLOAT;
    fManValue       : FLOAT;
    eMode       : E_CTRL_MODE;
    bHold       : BOOL;
END_VAR

fIn : Input variable of the oscillating PT2 element.

fManValue : Input value that is output in manual mode.

eState : State of the function block.

eMode : Input that specifies the block's operating mode.

bHold : A TRUE at this input will hold the internal state (and therefore also the output) constant at its current value, independently of the input value.

VAR_OUTPUT

VAR_OUTPUT
    fOut    : FLOAT;
    eState  : E_CTRL_STATE;
    eErrorId : E_CTRL_ERRORCODES;
    bError  : BOOL;
END_VAR

fOut : Output of the PT2 element.

eErrorId : Supplies the error number when the bError output is set.

bError : Becomes TRUE, as soon as an error occurs.

VAR_IN_OUT

VAR_IN_OUT
    stParams        : ST_CTRL_PT2oscillation_PARAMS;
END_VAR

stParams : Parameter structure of the oscillating PT2 element. This consists of the following elements:

TYPE
ST_CTRL_PT2oscillation_PARAMS :
STRUCT
    tCtrlCycleTime     : TIME     := T#0ms; (* controller cycle
time [TIME] *)
    tTaskCycleTime     : TIME     := T#0ms; (* task cycle time
[TIME] *)
    fKp        : FLOAT    := 0;     (* proportional
gain *)
    fTheta         : FLOAT    := 0;     (* damping ratio
*)
    tT0        : TIME     := T#0ms; (* T0 *)
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.

fKp : Proportional coefficient

fTheta : Damping ratio

tT0 : Characteristic time

Requirements