Siemens SIMATIC Operating Instructions Manual page 148

Diagnostic Data of Fail-Safe Modules
Channel-Specific Diagnostics Starting at Byte 28 to Byte 43 for 4/8 F-DI/4 F-DO
The channel-specific diagnostics start in byte 28 of the diagnostic data. Four bytes of
diagnostic information are provided per channel.
Figure A-11
148
Channel-Specific Diagnostics Starting in Byte 28 of the Diagnostic Data
ET 200pro Distributed I/O System - Fail-Safe Modules
Operating Instructions, 05/2007, A5E00394073-02