1  FUNCTION_BLOCK INTEGRAL

     2    VAR_INPUT

     3      RUN : BOOL ;       (* 1 = integrate, 0 = hold *)

     4      R1 : BOOL ;        (* Overriding reset        *)

     5      XIN : REAL ;       (* Input variable          *)

     6      X0  : REAL ;       (* Initial value           *)

     7      CYCLE : TIME ;     (* Sampling period         *)

     8    END_VAR

     9    VAR_OUTPUT

    10      Q : BOOL ;         (* NOT R1                  *)

    11      XOUT : REAL ;      (* Integrated output       *)

    12    END_VAR

    13    Q := NOT R1 ;

    14    IF R1 THEN XOUT := X0 ;

    15    ELSIF RUN THEN XOUT := XOUT + XIN * TIME_TO_REAL(CYCLE);

    16    END_IF ;

    17  END_FUNCTION_BLOCK

    18