FB_CTRL_LIMITER
This block limits an input signal to a parameterisable interval.
Description of the output behaviour:
VAR_INPUT
VAR_INPUT
fIn : FLOAT;
END_VAR
fIn : Input value for the function block.
VAR_OUTPUT
VAR_OUTPUT
fOut : FLOAT;
bMinLimit : BOOL;
bMaxLimit : BOOL;
eErrorId : E_CTRL_ERRORCODES;
bError : BOOL;
END_VAR
fOut : Output of the function block.
bMinLimit : A TRUE at this output indicates that the output has reached the lower limit.
bMaxLimit : A TRUE at this output indicates that the output has reached the upper limit.
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_LIMITER_PARAMS;
END_VAR
stParams : Parameter structure of the function block. This consists of the following elements:
TYPE
ST_CTRL_LIMITER_PARAMS:
STRUCT
tCtrlCycleTime : TIME := T#0ms; (*
controller cycle time [TIME] *)
tTaskCycleTime : TIME := T#0ms; (* task
cycle time [TIME] *)
fMinOutput : FLOAT;
fMaxOutput : FLOAT;
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.
fMinOutput : Lower limit at which the output is limited.
fMaxOutput : Upper limit at which the output is limited.