The operator is an extension of the IEC 61131-3 standard.

‎BITADR‎ yields the bit offset within a segment in a ‎DWORD‎.

NOTICE

The offset depends on whether the "Byte addressing" option is selected or cleared in the target system settings.

The highest value nibble (4 bits) in this ‎DWORD‎ defines the memory range.

Marker ‎M‎: ‎16#40000000‎

Input ‎I‎: ‎16#80000000‎

Output ‎Q‎: ‎16#C0000000‎

CAUTION

When using pointers to addresses, note that applying an online change can shift the contents of addresses.

VAR
    xVar AT %IX2.3 : BOOL;
    dwBitoffset : DWORD;
END_VAR

dwBitoffset := BITADR(xVar); (* If byte addressing = TRUE, result = 16#80000013; if byte addressing = FALSE, result =  16#80000023 *)