IO Addresses ST File - References - SIMATIC AX - AX Hardware Engineering documentation - Hardware Engineering,

Hardware Engineering reference
Portfolio
SIMATIC AX
Product
SIMATIC AX
Software version
2.0.0-alpha1.56
Edition
08/2025
Language
English (original)
Package Name
@ax/hw-docs

The IO addresses of a module will be stored as largest possible type inside the <ModuleName>_IoAddresses.st file.

  • 64bit --> LWORD
  • 32bit --> DWORD
  • 16bit --> WORD
  • 8bit --> BYTE
  • 1bit --> BOOL

If a module is larger than a whole data type, it will be divided (e.g. 48bit --> 3x WORD). Larger data types can be divided into smaller types or used for masking. This could used in the plc program like this:

PROGRAM MyProgram
    VAR_EXTERNAL
        Huge64BitModule : LWORD;
    END_VAR

    VAR
        Huge64BitModule_Half_0 :DWORD;
        Huge64BitModule_Secound_Half_0 :DWORD;
        Huge64BitModule_Quarter_0 :WORD;
        Huge64BitModule_Eigth_0 :BYTE;
        Huge64BitModule_bit_0 : BOOL;

    END_VAR

    VAR_TEMP

    END_VAR

    Huge64BitModule_Half_0 := Huge64BitModule.%D0;
    Huge64BitModule_Secound_Half_0 := Huge64BitModule.%D1;
    Huge64BitModule_Quarter_0 := Huge64BitModule_Half_0.%W0;
    Huge64BitModule_Eigth_0 := Huge64BitModule_Quarter_0.%B0;
    Huge64BitModule_bit_0 := Huge64BitModule_Eigth_0.%x0;

END_PROGRAM