VAR_INPUT

IN1 :REAL:=0.0;

LagTime : REAL := 5.0;

Sampletime : REAL := 0.2;

Pulse : BOOL :=FALSE;

END_VAR

VAR

FP_Pulse : BOOL := False;

OUT1_OLD :REAL:=0.0; 

END_VAR

VAR_OUTPUT

 OUT1 : REAL :=0.0;   

END_VAR

BEGIN 

IF  Pulse AND NOT FP_Pulse THEN

    IF (LagTime > 0.0) THEN 

         OUT1 := IN1 + ( OUT1_OLD - IN1)* EXP(-Sampletime/LagTime);

    ELSE

         OUT1:=IN1;

    END_IF;     

END_IF; 

FP_Pulse := Pulse;

OUT1_OLD := OUT1;

END_FUNCTION_BLOCK