AOUT.EXP

(* @NESTEDCOMMENTS := 'Yes' *)
(* @PATH := '\/Engineering\/signal processing' *)
(* @OBJECTFLAGS := '0, 8' *)
(* @SYMFILEFLAGS := '2048' *)
FUNCTION AOUT : DWORD
VAR_INPUT
	in : REAL;
END_VAR
VAR_INPUT CONSTANT
	Bits : BYTE;
	sign : BYTE := 255;
	low : REAL;
	high : REAL := 10.0;
END_VAR
VAR CONSTANT
	ff : DWORD := 2#1;
END_VAR
VAR
	in2 : REAL;
	sx : BOOL;
END_VAR

(*
version 1.4	23 feb 2008
programmer 	oscat
tested by		tobias

this module conditions an internal real value for D/A converter.
Aout converts and internal real value to a word for an D/A converter or other output devices.
The input value is converted to a n-bit wide output and a sign bit is set separately as specified.
the outout min value is set for the specified min input value and the max output is set for the max input value.
an input higher or lower then the max or min value will set the respective max or min value or the output.


*) 
(* @END_DECLARATION := '0' *)
(* if sign bit is defined *)
IF sign < 32 THEN
	sx := sign_R(in);
	in2 := ABS(in);
ELSE
	in2 := in;
END_IF;

(* begrenze in auf die zulässigen werte *)
in2 := LIMIT(low, in2, high);

(* Berechne den Ausgangswert *)
Aout := REAL_TO_DWORD((in2 - low) / (high - low) * DWORD_TO_REAL(SHL(ff,bits) -1));
IF sx THEN Aout := SHL(ff,sign) OR Aout; END_IF;

(*
revision history

hm 18.1.2007		rev 1.1
	renamed Modul to aout.
	changed Output to 32 Bit max.
	corrected error with sign bit.

hm	13.9.2007		rev 1.2
	changed code to avoid warning under codesys 2.8.1

hm	2. dec 2007		rev 1.3
	changed code for better performance

hm	23. feb 2008	rev 1.4
	changed code for better performance
*)
END_FUNCTION