FB_CTRL_LIN_INTERPOLATION

FB_CTRL_LIN_INTERPOLATION 1:

This function block performs linear interpolation to obtain values on the basis of a sampling points table.

Behavior of the output

fIn	fOut
arrTable[1,1] := 10;	arrTable[1,2] := 7;
arrTable[2,1] := 15;	arrTable[2,2] := 10;
arrTable[3,1] := 21;	arrTable[3,2] := 9;
arrTable[4,1] := 22;	arrTable[4,2] := 2;
arrTable[5,1] := 30;	arrTable[5,2] := 3;
arrTable[6,1] := 40;	arrTable[6,2] := 6;

FB_CTRL_LIN_INTERPOLATION 2:

VAR_INPUT

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

Name	Type	Description
fIn	FLOAT	Input value for the interpolation function block
fManValue	FLOAT	Input value that is output in manual mode.
bExtrapolate	BOOL	If this input is FALSE, then the value of the last interpolation point is output if the limits of the table are exceeded. If, however, it is TRUE, then extrapolation is performed on the basis of the last two interpolation points.
eMode	E_CTRL_MODE	Input that specifies the operation mode of the function block.

VAR_OUTPUT

VAR_OUTPUT
    fOut                        : FLOAT;
    bInIsGreaterThanMaxElement  : BOOL;
    bInIsLessThanMinElement     : BOOL;
    eState                      : E_CTRL_STATE;
    eErrorId                    : E_CTRL_ERRORCODES;
    bError                      : BOOL;
END_VAR

Name	Type	Description
fOut	FLOAT	Table value from linear interpolation
bInIsGreater ThanMax Element	BOOL	A TRUE at this output indicates that the input value is greater than the largest interpolation point.
bInIsLessThan Min Element	BOOL	A TRUE at this output indicates that the input value is smaller than the smallest interpolation point.
eState	E_CTRL_ STATE	State of the function block
eErrorId	E_CTRL_ ERRORCODES	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_LIN_INTERPOLATION_PARAMS;
END_VAR

Name	Type	Description
stParams	ST_CTRL_LIN_INTERPOLATION_ PARAMS	Parameter structure of the interpolation element

stParams consists of the following elements:

TYPE ST_CTRL_2POINT_PARAMS :
STRUCT
    tCtrlCycleTime           : TIME := T#0ms;
    tTaskCycleTime           : TIME := T#0ms;
    pDataTable_ADR           : POINTER TO FLOAT := 0;
    nDataTable_SIZEOF        : UINT     := 0;
    nDataTable_NumberOfRows  : UINT     := 0;
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.
pDataTable_ ADR	POINTER TO FLOAT	Address of the n x 2 array on which linear interpolation is to be carried out.
nDataTable_ SIZEOF	UINT	Size of the n x 2 array
nDataTable_ NumberOfRows	UINT	Number of rows in the array