Partial access of ANY_BIT variables

Syntax

variable_name.size#

Meaning

partial access to →variables of one of the following ANY_BIT data types: BYTE, WORD, DWORD or LWORD

Enhancement to IEC-standard

logi.CAD 3 supports the write access to a bit, byte, word or double word of a variable, too. This write access is an enhancement to the →IEC-standard.

The following data is necessary to address a part of a variable:

variable_name = name of the variable
. = separator

size = prefix for the size
Supported prefixes and their meaning:

`%X`, only % or no prefix at all	bool (single bit)
`%B`	byte (8 bits)
`%W`	word (16 bits)
`%D`	double word (32 bits)
`%L`	long word (64 bits)

# = corresponding bit, byte, word, double word or long word
These specifications are integer literals (ranging from 0 for the least significant part up to the literal for the most significant part).

Access to	for data type	literal	syntax
bit (`BOOL`)	`BYTE`	`0` to `7`	`variable_name.%X0` to `variable_name.%X7`
	`WORD`	`0` to `15`	`variable_name.%X0` to `variable_name.%X15`
	`DWORD`	`0` to `31`	`variable_name.%X0` to `variable_name.%X31`
	`LWORD`	`0` to `64`	`variable_name.%X0` to `variable_name.%X63`
byte (`BYTE`)	`WORD`	`0` to `1`	`variable_name.%B0` to `variable_name.%B1`
	`DWORD`	`0` to `3`	`variable_name.%B0` to `variable_name.%B3`
	`LWORD`	`0` to `7`	`variable_name.%B0` to `variable_name.%B7`
word (`WORD`)	`DWORD`	`0` to `1`	`variable_name.%W0` to `variable_name.%W1`
word (`WORD`)	`LWORD`	`0` to `3`	`variable_name.%W0` to `variable_name.%W3`
double word (`DWORD`)	`LWORD`	`0` to `1`	`variable_name.%D0` to `variable_name.%D1`
long word (`LWORD`)	`LWORD`	`0`	`variable_name.%L0`

Example

VAR
  VarBo : BOOL;
  VarBy1, VarBy2 : BYTE;
  VarLW : LWORD;
  VarW : WORD;
  VarDW : DWORD;
END_VAR;
 
(* reading accesses *)
VarBo := VarBy1.%X0;  (* 'Bit 0' of 'VarBy1' is assigned to 'VarBo'. *)
VarBo := VarBy1.%7;   (* 'Bit 7' of 'VarBy1' is assigned to 'VarBo'. *)
                      (* 'VarBy1.%7' is interpreted as 'VarBy1.%X7' or 'VarBy1.7'. *)
VarBo := VarLW.63;    (* 'Bit 63' of 'VarLW' is assigned to 'VarBo'. *)
                      (* 'VarLW.63' is interpreted as 'VarLW.%X63' or 'VarLW.%63'. *)
VarBy1 := VarW.%B1;   (* 'Byte 1' of 'VarW' is assigned to 'VarBy1'. *)
VarW := VarLW.%W3;    (* 'Wort 3' of 'VarLW' is assigned to 'VarW'. *)
 
(* writing accesses *)
VarBy2.4 := TRUE;     (* 'TRUE' is assigned to 'bit 4' of 'VarBy2'. *)
                      (* 'VarBy2.4' is interpreted as 'VarBy2.%X4' or 'VarBy2.%4'. *)
VarDW.%B2 := 16#F0;   (* '16#F0' is assigned to 'byte 2' of 'VarDW'. *)