Siemens SIMATIC Ident Function Manual page 104

Programming communications modules
B.2 Cyclic control word between master and communications module
Synchronizing of command and acknowledgment counters
The command (BZ) and acknowledgment (QZ) counters are synchronized during a startup.
The CM sets QZ = 0 and BZ = 1. The startup can be triggered by both the CM (return of
power) and the user (init_run_).
Figure B-4
Figure B-5
104
Power-up timing initiated by user
Startup timing of the CM initiated by power down
FB 45 for MOBY U, MOBY D, RF200, RF300
Function Manual, 07/2012, J31069-D0166-U001-A4-7618