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ControlWin Modbus slave exceptions
https://forum.codesys.com/viewtopic.php?f=24&t=8156
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Author:  mstelt [ Thu Sep 14, 2017 2:09 pm ]
Post subject:  ControlWin Modbus slave exceptions

I have a PC running control win as a slave and a SCADA program which is the master.

When I run both the Control win and the SCADA program on the same PC I get exceptions on my modbus messages. When I install one PC with control win and another one with the SCADA program everything works fine. I'm trying to read and write.

This is the log that I captured with Wireshark when both are running on the same PC:

1 0.000000 192.168.1.150 192.168.1.150 Modbus/TCP 52 Query: Trans: 16482; Unit: 1, Func: 4: Read Input Registers
3 0.004993 192.168.1.150 192.168.1.150 Modbus/TCP 55 Query: Trans: 32866; Unit: 1, Func: 16: Write Multiple Registers
5 0.004993 192.168.1.150 192.168.1.150 Modbus/TCP 49 Response: Trans: 16482; Unit: 1, Func: 4: Read Input Registers. Exception returned
7 1.000250 192.168.1.150 192.168.1.150 Modbus/TCP 52 Query: Trans: 16483; Unit: 1, Func: 4: Read Input Registers
9 1.000250 192.168.1.150 192.168.1.150 Modbus/TCP 55 Query: Trans: 32867; Unit: 1, Func: 16: Write Multiple Registers
11 1.001251 192.168.1.150 192.168.1.150 Modbus/TCP 49 Response: Trans: 16483; Unit: 1, Func: 4: Read Input Registers. Exception returned

This is the log when running on different PC's

1 0.000000 192.168.1.200 192.168.1.201 Modbus/TCP 66 Query: Trans: 16426; Unit: 1, Func: 4: Read Input Registers
2 0.000280 192.168.1.201 192.168.1.200 Modbus/TCP 65 Response: Trans: 16426; Unit: 1, Func: 4: Read Input Registers
3 0.000988 192.168.1.200 192.168.1.201 Modbus/TCP 69 Query: Trans: 32810; Unit: 1, Func: 16: Write Multiple Registers
4 0.001244 192.168.1.201 192.168.1.200 Modbus/TCP 66 Response: Trans: 32810; Unit: 1, Func: 16: Write Multiple Registers
8 1.503473 192.168.1.200 192.168.1.201 Modbus/TCP 66 Query: Trans: 16427; Unit: 1, Func: 4: Read Input Registers
9 1.504294 192.168.1.201 192.168.1.200 Modbus/TCP 65 Response: Trans: 16427; Unit: 1, Func: 4: Read Input Registers

What could be wrong?

Author:  Edwin Schwellinger [ Thu Sep 21, 2017 11:12 am ]
Post subject:  Re: ControlWin Modbus slave exceptions

Hi,
either you need to add the exception code or add a wireshark capture.

BR
Edwin

Author:  mstelt [ Mon Oct 02, 2017 3:15 pm ]
Post subject:  Re: ControlWin Modbus slave exceptions

Hi,

I don't get a exception code. The pasted lines above are copied fro the Wireshark log file.

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