CHARCURVE (FB)¶

FUNCTION_BLOCK CHARCURVE

Maps an input signal onto a characteristic curve

The characteristic curve is given by an array of POINTs, which include a set of X-values with their corresponding Y-values.

Example in ST:

VAR
CHARACTERISTIC_LINE:CHARCURVE;
KL:ARRAY[0..10] OF POINT := [(X:=0,Y:=0),(X:=250,Y:=50),
(X:=500,Y:=150),(X:=750,Y:=400), 7((X:=1000,Y:=1000))];
COUNTER : INT;
END_VAR

COUNTER := COUNTER+10; supply CHARCURVE with for example a constantly increasing value
CHARACTERISTIC_LINE(IN := COUNTER,N := 5,P := KL);

Illustration of the resulting curve

InOut:

Scope	Name	Type	Comment
Input	IN	INT	Input signal
	N	BYTE	Number of points defining the characteristic curve : 2 <= N <= 11
Inout	P	ARRAY [0..10] OF POINT	Array of points to describe the characteristic curve
Output	OUT	INT	Output variable, contains the manipulated value
	ERR	BYTE	0 : No error 1 : Error in P: wrong sequence (completely tested, only if IN is equal to largest X-value of P) 2 : IN outside of limits of P 4 : N invalid, number of points not within the allowed range 2..11