FB_CTRL_HYSTERESIS
The function block provides a hysteresis transfer element in a functional diagram.
Transfer function:
VAR_INPUT
VAR_INPUT
fIn : FLOAT;
bManSyncValue : BOOL;
bSync : BOOL;
eMode : E_CTRL_MODE;
END_VAR
fIn : Input of the hysteresis element.
bManSyncValue : Input through which the hysteresis element can be set to one of the two junctions.
bSync : A rising edge at this input sets the hysteresis element to the value fManSyncValue.
eMode : Input that specifies the operation mode of the function block.
VAR_OUTPUT
VAR_OUTPUT
bOut : BOOL;
eState : E_CTRL_STATE;
eErrorId : E_CTRL_ERRORCODES;
bError : BOOL;
END_VAR
bOut : Output of the hysteresis 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 situation occurs.
VAR_IN_OUT
VAR_IN_OUT
stParams : ST_CTRL_HYSTERESIS_PARAMS;
END_VAR
stParams : Parameter structure of the hysteresis element. This consists of the following elements:
TYPE
ST_CTRL_HYSTERESIS_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.