Configuration and operation 
  6.8 Media redundancy 
CP 443-1 Advanced (GX30) 
Manual, 03/2019, C79000-G8976-C256-05 
77 
The IO device being used as a shared device will only take part in data exchange if the 
higher-level I/O controllers are configured identically in terms of using routers. 
You should therefore configure the PROFINET interfaces on the other IO controllers as 
follows: 
●  The IP address of the PROFINET interface of the CP is used as the router address. 
or 
●  The CP being used as the IO controller and all other IO controllers use the same IP 
address as the router address. 
 
You can use the CP in a ring topology with media redundancy. The CP itself can be 
redundancy manager. 
For more detailed information on configuration, refer to the online help of the "Media 
redundancy" parameter group and in Part A of the manual /2/ (Page 118). 
 
Note 
If you are using IRT communication, no media redunda
ncy is supported. 
 
Interface in the user program 
6.9.1
 
Call interface for open communications services SEND/RECV 
Change call parameters only after job confirmation 
 
Note 
Note the following for the call interface of the program blocks AG_SEND / AG_LSEND / 
AG_
SSEND or AG_RECV / AG_LRECV / AG_SRECV: 
Once the job has been triggered, you can only make changes again after the program block 
has confirmed completion of the job with DONE=1 or with ERROR=1.
 
If this is ignored, it is possible that the execution of the j
ob will be aborted with an error and 
resources could be permanently occupied on the CPU.