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ethernet connecting to a server

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We have a V350 and a V1040.  Both have basically the same ladder logic for connecting to a server.  The 350 connects as it should.  The 1040 appears to connect for about a half a second even though the ladder logic should keep it open on a 5 sec timer.  The server is getting data from the 350, but not the 1040.  The server program looks good for both.  The only difference I can see is the model of PLC.  We can go online, download, etc., over  ethernet, so thats good.  Any suggestions anyone?




DanWinder 4.vlp

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Can you provide more info:


a) What protocol server is using to get the data (PCOM, Modbus or other)?

B) What the values of SI105, SI143 and SI147 at the time of connection (SB149=1)?


2. Install on the server Wireshark, set filter as tcp.port ==502 and capture the trafic .  Attach the snapshot.

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On your snapshot i can see only packets from the server, there is no replies from PLC, so it hard to define who  terminated the connection, however from PLC side the only reason may be is a small value of SI105 (Socket 2 TCP/IP Keep Alive (units of 100 msec). Try to set it to SI105=50 (5sec).

SI143=0 tells that socket configured correctly and SI149=6 - connection was established.


The problem may be on the server side. Borth PLC's trying to connect to the same port (502), but again you can see it only on wireshark snapshot of bi-directional traffic .

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