lib/ramp_st.txt
author Andrey Skvortsov <andrej.skvortzov@gmail.com>
Sun, 14 Oct 2018 20:14:13 +0300
changeset 1073 24ef30a9bcee
parent 276 1679f514f38a
permissions -rwxr-xr-x
revert commits improved performance of some extensible Standard Functions (ADD, MUL, AND, OR, XOR)

Following commits are reverted:
mjsousa 0b275a2 improve performance of some extensible Standard Functions (ADD, MUL, AND, OR, XOR) -- increase hardcoded limit to 499
mjsousa 2228799 improve performance of some extensible Standard Functions (ADD, MUL, AND, OR, XOR) -- Add comments!!
mjsousa ce81fa6 improve performance of some extensible Standard Functions (ADD, MUL, AND, OR, XOR)"

The reason is that they cause regression in some cases (if function is
used as argument for function block, for example) and this is not
fixed for a long time.
(* Following taken directly from the IEC 61131.3 draft standard *)

(*
 * An IEC 61131-3 IL and ST compiler.
 *
 * Based on the
 * FINAL DRAFT - IEC 61131-3, 2nd Ed. (2001-12-10)
 *
 *)

 FUNCTION_BLOCK RAMP
   VAR_INPUT
     RUN : BOOL ;      (* 0 - track X0, 1 - ramp to/track X1 *)     
     X0,X1 : REAL ;
     TR : TIME ;       (* Ramp duration *)
     CYCLE : TIME ;    (* Sampling period *)
   END_VAR
   VAR_OUTPUT
     BUSY : BOOL ; (* BUSY = 1 during ramping period *)
     XOUT : REAL := 0.0 ;
   END_VAR
   VAR XI : REAL ;       (* Initial value *)
       T : TIME := T#0s; (* Elapsed time of ramp *)
   END_VAR
   BUSY := RUN ;
   IF RUN THEN
      IF T >= TR THEN BUSY := 0 ; XOUT := X1 ;
      ELSE XOUT := XI + (X1-XI) * TIME_TO_REAL(T)
                                / TIME_TO_REAL(TR) ;
           T := T + CYCLE ;
      END_IF ;
   ELSE XOUT := X0 ; XI := X0 ; T := t#0s ;
   END_IF ;
 END_FUNCTION_BLOCK