andreagoni76

I wrote wrong, it's a CompactLogix..

 

 I have the same issue, but I successfully communicated S7-1515T-2PN with 1756-L71 for both send and receive with DB_Data size of 100 bytes and with data length of 16 bytes. The setup I have is 1756-L71 is the server and the S7-1515T-2PN is the client.

The problem I face is the moment I sent a 4byte size data (DINT, REAL) from 1756-L71 PLC to S7-1515T-2PN it does not receive fully the data or the data received is wrong and the following byte address from the byte address I configure to receive are not working at all.

I configure from S7-1500 side to receive a 4byte size data from 1756-L71 and the by address I used is byte0, it should write the data from byte 0 until byte 3 since it is 4bytes of data but that's not happening. Furthermore byte address 4 onwards are not working once I start transferring 4 bytes size data to byte address 0 from 1756-L71 to S7-1515T.

Attached snapshots status of the T_COMM block from S7-1515T-2PN side

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Split from Using T_COMM With Allen Bradley - need to transfer and receive 1200 bytes.

Recently I tried to use T_COMM and did not succeed. I am currently using CIP Client and is happy with it. It is a one sided configuration and there is feedback (good/bad) if the data is usable.

One drawback is that it may take up to 3 minutes or so to establish communications initially. There is also the need to detect if communication is failing. Communication needs to be broken down and built-up again when communication failed (partner disconnected).