FB_CTRL_3POINT

Behaviour of the output:

VAR_INPUT

VAR_INPUT
    fSetpointValue  : FLOAT;
    fActualValue    : FLOAT;
    nManSyncValue   : INT;
    bSync       : BOOL;
    eMode       : E_CTRL_MODE;
END_VAR

fSetpointValue : Set value of the controlled variable.

fActualValue : Actual value of the controlled variable.

nManSyncValue : Input through which the 3-point element can be set to one of the three branches.

nManSyncValue >= 1 → bPosOut = TRUE, bNegOut = FALSE
nManSyncValue <= -1 → bPosOut = FALSE, bNegOut = TRUE
otherwise → bPosOut = FALSE, bNegOut = FALSE

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

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

VAR_OUTPUT

VAR_OUTPUT
    bPosOut         : BOOL;
    bNegOut         : BOOL;
    eState      : E_CTRL_STATE;
    eErrorId        : E_CTRL_ERRORCODES;
    bError      : BOOL;
END_VAR

bPosOut : This output from the 3-point element is TRUE if the upper junction of the characteristic curve is active.

bNegOut : This output from the 3-point element is TRUE if the lower junction of the characteristic curve is active.

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_PARAMS;
END_VAR

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

TYPE
ST_CTRL_3POINT_PARAMS :
STRUCT
    tCtrlCycleTime     : TIME     := T#0ms; (* controller cycle
time [TIME] *)
    tTaskCycleTime     : TIME     := T#0ms; (* task cycle time
[TIME] *)
    fPosOutOn      : FLOAT;         (* switch to
bPosOut on *)
    fPosOutOff     : FLOAT;         (* switch to
bPosOut off *)
    fNegOutOn      : FLOAT;         (* switch to
bNegOut on *)
    fNegOutOff     : FLOAT;         (* switch to
bNegOut off *)
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.

fPosOutOn : Control deviation that will result in bPosOut = FALSE being switched to bPosOut = TRUE (bNegOut = FALSE).

fPosOutOff : Control deviation that will result in bPosOut = TRUE being switched to bPosOut = FALSE (bNegOut = FALSE).

fNegOutOn : Control deviation that will result in bNegOut = FALSE being switched to bNegOut = TRUE (bPosOut = FALSE).

fNegOutOff : Control deviation that will result in bNegOut = TRUE being switched to bNegOut = FALSE (bPosOut = FALSE).

Requirements