profibus and satelline

Hi. I use satelline 3AS modems for wireless link between two simatic stations S7300 with cp343-5 and s7400 with cp443-5.
They both are configured as master at 9600kbps. like here
http://republika.pl/asdfg3/pb.JPG
Usally this connection work correct, but sometimes cp443-5 is still transmitting data and cp343-5 signaling BUSF. Then i must (at this same time) restart both of modems. I'll be grateful for some advice. Thanks.
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Pawel,
1. The Siemens Profibus CP modules you are using are not designed to be used on a radio network - they cannot tolerate variable turn-around delays. This means that they may work for a while and then stop.
2. Your radio modems are not designed to work with Profibus. You don't say what environment you are working in, but there are a few manufacturers out there who make Profibus-compatible wireless modems (eg. www.sick.de) To work with Profibus, the modem link must be full-duplex (2-channel) and provide buffering and hardware handshaking information that you won't necessarily get on a typical radio modem.
For the modems you have, make sure that the modem link speed is at least twice your baud rate. If you have already done this and it still fails, I would suggest purchasing profibus-compatible modems.
I hope this helps. Cameron:-)
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