msousa@276: (* Following taken directly from the IEC 61131.3 draft standard *)
msousa@276: 
msousa@276: (*
msousa@276:  * An IEC 61131-3 IL and ST compiler.
msousa@276:  *
msousa@276:  * Based on the
msousa@276:  * FINAL DRAFT - IEC 61131-3, 2nd Ed. (2001-12-10)
msousa@276:  *
msousa@276:  *)
msousa@276: 
lbessard@192:  FUNCTION_BLOCK INTEGRAL
lbessard@192:    VAR_INPUT
lbessard@192:      RUN : BOOL ;       (* 1 = integrate, 0 = hold *)
lbessard@192:      R1 : BOOL ;        (* Overriding reset        *)
lbessard@192:      XIN : REAL ;       (* Input variable          *)
lbessard@192:      X0  : REAL ;       (* Initial value           *)
lbessard@192:      CYCLE : TIME ;     (* Sampling period         *)
lbessard@192:    END_VAR
lbessard@192:    VAR_OUTPUT
lbessard@192:      Q : BOOL ;         (* NOT R1                  *)
lbessard@192:      XOUT : REAL ;      (* Integrated output       *)
lbessard@192:    END_VAR
lbessard@192:    Q := NOT R1 ;
lbessard@192:    IF R1 THEN XOUT := X0 ;
lbessard@192:    ELSIF RUN THEN XOUT := XOUT + XIN * TIME_TO_REAL(CYCLE);
lbessard@192:    END_IF ;
lbessard@192:  END_FUNCTION_BLOCK
lbessard@192: