--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/lib/integral_st.txt	Wed Jun 10 15:02:14 2009 +0200
@@ -0,0 +1,18 @@
+ FUNCTION_BLOCK INTEGRAL
+   VAR_INPUT
+     RUN : BOOL ;       (* 1 = integrate, 0 = hold *)
+     R1 : BOOL ;        (* Overriding reset        *)
+     XIN : REAL ;       (* Input variable          *)
+     X0  : REAL ;       (* Initial value           *)
+     CYCLE : TIME ;     (* Sampling period         *)
+   END_VAR
+   VAR_OUTPUT
+     Q : BOOL ;         (* NOT R1                  *)
+     XOUT : REAL ;      (* Integrated output       *)
+   END_VAR
+   Q := NOT R1 ;
+   IF R1 THEN XOUT := X0 ;
+   ELSIF RUN THEN XOUT := XOUT + XIN * TIME_TO_REAL(CYCLE);
+   END_IF ;
+ END_FUNCTION_BLOCK
+