Beckhoff CX B110 Series, Manual

Page: 30 / 58

Parameterization and commissioning
CXxxxx-B110 30 Version: 1.3
Data structure sample
byTest: BYTE;
udTest: UDINT;
ARM address ARM variable Address x86 ARM variable
Byte Offset 0 Byte Byte Offset 0 BYTE
Byte Offset 4 UDINT Byte Offset 1 UDINT
Sum: 8 byte Sum: 5 byte
You can determine the length of a data structure on both systems using the command SIZEOF. If there is a
difference here, this indicates that something is wrong with the data structure.
This problem can be solved by more skillful arrangement of the variables or by working with filler or dummy
variables.
ARM address ARM variable Address x86 ARM variable
Byte Offset 0 Byte Byte Offset 0 BYTE
Byte Offset 1 BYTE (Dummy1)
Byte Offset 2 BYTE (Dummy2)
Byte Offset 3 BYTE (Dummy3)
Byte Offset 4 UDINT Byte Offset 4 UDINT
Sum: 8 byte Sum: 8 byte
Filler or dummy variables can be used to adjust the length of the data structure, in order to avoid problems
caused by potential differences.