FB_CTRL_ACTUAL_VALUE_FILTER

FB_CTRL_ACTUAL_VALUE_FILTER 1:

The function block allows a measured input value to be checked for plausibility and filtered.

Behavior of the output

This function block allows a plausibility check to be carried out on a measured input value. If the difference between two sampling values in sequence (measurements) is larger than the specified window, fDeltaMax, then the current input value is suppressed for a maximum of three cycles. During this time the output value is extrapolated from the previous input values. If the specified window is exceeded for more than three cycles, the output will again follow the input value. The behavior of the output is illustrated in the diagram above.

VAR_INPUT

VAR_INPUT
    fIn        : FLOAT;
    fManValue  : FLOAT;
    eMode      : E_CTRL_MODE;
END_VAR

Name	Type	Description
fIn	FLOAT	Input value of the filter
fManValue	FLOAT	Input value that is output in manual mode.
eMode	E_CTRL_MODE	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

Name	Type	Description
fOut	FLOAT	Output of the function block
eState	E_CTRL_ STATE	State of the function block
eErrorId	E_CTRL_ ERROR CODES	Supplies the error number when the output `bError` is set.
bError	BOOL	Becomes TRUE, as soon as an error occurs.

VAR_IN_OUT

VAR_IN_OUT
    stParams    : ST_CTRL_ACTUAL_VALUE_FILTER_PARAMS;
END_VAR

Name	Type	Description
stParams	ST_CTRL_ACTUAL_VALUE_FILTER_ PARAMS	Parameter structure of the actual value filter element

stParams consists of the following elements:

TYPE
ST_CTRL_ACTUAL_VALUE_FILTER_PARAMS:
STRUCT
    tCtrlCycleTime    : TIME := T#0ms;
    tTaskCycleTime    : TIME := T#0ms;
    fDeltaMax         : FLOAT;
END_STRUCT
END_TYPE

Name	Type	Description
tCtrlCycleTime	TIME	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	TIME	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.
fDeltaMax	FLOAT	Maximum difference between two input values in sequence. See description above.