FB_CTRL_3POINT_EXT

Behaviour of the output:

fIn := fSetpointValue - fActualValue;

VAR_INPUT

VAR_INPUT
    fSetpointValue  : FLOAT;
    fActualValue    : FLOAT;
    fManSyncValue   : FLOAT;
    bSync           : BOOL;
    eMode           : E_CTRL_MODE;
END_VAR

fSetpointValue : Setpoint of the controlled variable.

fActualValue : Actual value of the controlled variable.

fManSyncValue : Input through which the extended 3-point element can be set to one of the junctions.

| fManSyncValue | < 1 → fOut = 0.0
| fManSyncValue | >= 1 → fOut = fE * fGain + fOffset

bSync : A rising edge at this input sets the 3-point element to the value fManSyncValue.

eMode : Input that specifies the operation mode of the function block.

VAR_OUTPUT

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

fOut : Output of the extended 3-point element.

eState : State of the function block.

nErrorID : Returns the ADS 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_3POINT_EXT_PARAMS;
END_VAR

stParams : Parameter structure of the extended 3-point element. This consists of the following elements:

TYPE
ST_CTRL_3POINT_EXT_PARAMS :
STRUCT
    tCtrlCycleTime     : TIME := T#0ms; (* controller cycle
time [TIME] *)
    tTaskCycleTime     : TIME := T#0ms; (* task cycle time
[TIME] *)
    fOutOff        : FLOAT;     (* x-parameter for
threshold OFF *)
    fOutOn         : FLOAT;     (* x-parameter for
threshold ON *)
    fGain          : FLOAT;     (* y-parameter gain
*)
    fOffset        : FLOAT;     (* y-parameter offset
*)
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.

fOutOff : If the system deviation falls below this value, the output is switched off (set to zero).

fOutOn : If the control deviation exceeds this value, the output is switched on.

fGain : Gain factor.

fOffset : Offset.

Requirements