S7-400H redundant communication with S7-300 on Ethernet

nevaland

I have been posting around the forums for the above mentioned problem for quite some time now. Since there is no direct or standard method to communicate 400H system with 300 over redundandt ethernet, im facing lots of problems to make it happen.

I have come across ModbusTCP, which looks to me a viable solution for this. Actually I want to configure multiple 315-2DP's as slaves of a single 400H system. Let me know if this can be done in its entirely using ModbusTCP. Also, if there are any limitations of ModbusTCP, like data handling and exchange.