Intermittent Modbus TCP Timeouts

Ewon Support
#1

I am experiencing intermittent Modbus TCP timeouts with an EC350 communicating with a PLC. All of the data is available in the controller, but sometimes the EC350 will grab 90% of the values, all of the values, or no values. The ones that are not retrieved display “DS: Timeout”. I have tried debugging this to no avail - I have over 100 systems (EC350 and this same PLC) that have zero issues, but this specific unit I cannot get to function 100%. This system does use a different template/profile, but all the data points are valid, etc. Looking for any specific help determining the cause(s) of these timeout issues.

Allen

#2

Hello @allen,

This sounds like it might be an issue on the LAN side of the Netbiter. If you look at the Communication statistics under management what errors do you see? This should give you some indication of the issue. Also you can hover over a parameter in the dashboard when it is failing to be read you should see an error response.

Deryck

#4

I receive strictly timeout errors – sometimes I get mostly valid responses and just a few timeouts, but sometimes many more (or none at all). The error on each parameter is always “DS: Time out”

#5

Photo attached of my most recent refresh

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#6

Hello Allen,

This points towards a issue with the network or the device itself. Where it is time outs we are sending out the query but we are not seeing a response back. Is the PLC being powered off or disconnected at these times?

A wireshark capture might provide you with a better idea on what is happening. You could capture traffic at the Netbiter and at the PLC then compare to make sure the Netbiter is sending the message and see if the PLC is receiving it.

Deryck