--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/AnnexF/lag1_st.txt	Wed Jan 31 15:32:38 2007 +0100
@@ -0,0 +1,16 @@
+ FUNCTION_BLOCK LAG1
+   VAR_INPUT
+     RUN : BOOL ;     (* 1 = run, 0 = reset *)
+     XIN : REAL ;     (* Input variable *)
+     TAU : TIME ;     (* Filter time constant *)
+     CYCLE : TIME ;   (* Sampling time interval *)
+   END_VAR
+   VAR_OUTPUT XOUT : REAL ; END_VAR  (* Filtered output *)
+   VAR K : REAL ;     (* Smoothing constant, 0.0<=K<1.0 *)
+   END_VAR
+   IF RUN THEN XOUT := XOUT + K * (XIN - XOUT) ;
+   ELSE XOUT := XIN ;
+        K := TIME_TO_REAL(CYCLE) / TIME_TO_REAL(CYCLE + TAU) ;
+   END_IF ;
+ END_FUNCTION_BLOCK
+