Author Topic: Modbus TCP - No Response from PLC(21)  (Read 5876 times)

iamjer76

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Re: Modbus TCP - No Response from PLC(21)
« Reply #15 on: July 12, 2015, 10:46:10 AM »
The machine touchscreen also communicates to the PLC, but that is it. The PLC can accept 2 connections at once so this shouldn't be an issue as it still leaves a connection for this project.

Godra

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Re: Modbus TCP - No Response from PLC(21)
« Reply #16 on: July 12, 2015, 04:51:59 PM »
You can always do a quick test by temporarily disconnecting the touchscreen.

That way you would eliminate the touchscreen as possible cause.

Archie

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Re: Modbus TCP - No Response from PLC(21)
« Reply #17 on: July 12, 2015, 05:38:59 PM »
Both Godra and myself are getting the same results with our tests, so we first have to figure why you are getting something different to make sure I am looking at the correct Wireshark information. The only thing I can think of is maybe the test you ran was on 3.98s and our test was on 3.98t. Can you run the same test on 3.98t and do another WireShark capture?

Is it possible that you have another software on your PC running in the background such as an OPC server that may be communicating with your controller?

iamjer76

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Re: Modbus TCP - No Response from PLC(21)
« Reply #18 on: July 12, 2015, 10:52:28 PM »
This is now working! I don't have a reason as to why aside from the fact that I rebooted my computer. Thank you all for your time as you have been very helpful and I can't express my gratitude enough.