the only possibility which I see at the moment is to use CODESYS and Raspberry Pi plc
http://store.codesys.com/codesys-contro ... pi-sl.html
this run for 2h in demo mode full, sure could be licensed.
The profinet master will be released to 3.5SP6 version which is scheduled for end of the year.
maybe a beta version is available for testing purpose.
Attention your Siemens plc should then be a profinet slave! The Raspberry Pi is the Profinet Master