FB_CTRL_2POINT
The function block provides a 2-point transfer element in the functional diagram.
Behaviour of the output:
VAR_INPUT
VAR_INPUT
fSetpointValue : FLOAT;
fActualValue : FLOAT;
bManSyncValue : BOOL;
bSync : BOOL;
eMode : E_CTRL_MODE;
END_VAR
fSetpointValue : Set value of the controlled variable.
fActualValue : Actual value of the controlled variable.
bManSyncValue : Input through which the 2-point element can be set to one of the two branches.
bSync : A rising edge at this input sets the 2-point element to the value bManSyncValue.
eMode : Input that specifies the block's operating mode.
VAR_OUTPUT
VAR_OUTPUT
bOut : BOOL;
eState : E_CTRL_STATE;
eErrorId : E_CTRL_ERRORCODES;
bError : BOOL;
END_VAR
bOut : Output of the 2-point element.
eState : State of the function block.
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_2POINT_PARAMS;
END_VAR
stParams : Parameter structure of the 2-point element. This consists of the following elements:
TYPE
ST_CTRL_2POINT_PARAMS :
STRUCT
tCtrlCycleTime : TIME := T#0ms; (* controller cycle
time [TIME] *)
tTaskCycleTime : TIME := T#0ms; (* task cycle time
[TIME] *)
fHysteresisRange : FLOAT; (* range of the
hysteresis loop *)
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.
fHysteresisRange: Hysteresis range, see image above.