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

Neuron Power Engineer 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

    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'. *)