Error smbs-Read TCP header failed

Ewon Support Ewon Flexy
#1

Hi all,

I have a weird problem that I can’t find a solution to.

I have 4 tags that I am getting from a Modbus-Client

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For some reason, the tag “Voltage” and “Power_Totalizer” is constantly having a bad communication. But on occasion, it will get a reading. I have also tested getting the reading with Modbus-Poll and I am reading the values without any issue.

I tried checking the event logs and i have this error: smbs-Read TCP header failed.

Any idea to why this is happening?

#2

The error with the 2nd register could be caused by grouping the data with the first. Can you set ‘MaxDeltaRegX:1’ in the Modbus IO Server Advanced Parameters?

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What is the poll rate set to?

Do you ever get a good reading for Voltage?

Can you used a managed switch to get a packet capture of the traffic?

Can you make a backup of the Ewon using eBuddy and check the box for “Include Support Files”?

#3

Hi Kyle,

Thanks for the reply.

I’ve tried changing the MaxDeltaRegX to 1, seems to be slightly better. My Voltage tag doesnt have any errors but my other tags seems to be affected.

Here’s the poll rates I used, i tried to group my tags to the topics and play around with it to get the best outcome. But there’s always some tags that have error.

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Unfortunately i cant use a managed switch because it’s now installed on a remote site and I won’t be able to go there in the next few days.

I have also attached the Ewon support files.
eWON.tar (168.5 KB)

#5

The next best thing would be to check “Disable Tags in Error” in the Global IO Server settings. Then you should be able to check the Event Logs which will give you error messages about why the tags are being disabled.

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#6

I would also advise you to create a support case at https://support.hms-networks.com as that will put you in touch with your local HMS Support team who could probably provide better support for you. My office will be closing today until 12/27 for Christmas.
Make sure to include the backup with support files after disabling the tags in error.

Best Regards,
Kyle

#7

Hi again Kyle,

I have actually activated the “Disable Tags in Error” so the backup file i provided in the previous post includes that as well.
I will also create a case with the support.

Happy Holidays!

Best regards,
Vince

#8

Thank you! Happy holidays to you as well!

I see that a case was created. I would also include a full backup with support files. Due to the holidays, there may be some delay in response times, but the Ewon team should be able to help you out with this problem.