Modbus TCP, Mudbus & UNO: communication speed

Projects Networking, Protocols, and Devices
1

Hello,

I have made a setup with a plc (Wago controller) and a UNO, using the mudbus library.
The plc writes each second a value to a modbus tcp register of the arduino.

Now, I have an issue which I cannot explain:

  • I have adapted the write speed to 100ms ( which I presume is too fast for the network or arduino)
  • I sent data for about 5 minutes, after that, nothing is sent by the plc.
  • I have noticed the sent values are "somewhere" stored and the registers in the arduino are changing for a long time.
  • After I hit the reset button on the arduino, after restart, the registers continue to change.
  • Only after removing the power from the arduino, and reapplying the change of the registers is stopped.

So, is there any buffer or something that explains this behavior?

2

something that explains this behavior?

The Arduino does not have modbus tcp registers. So, no, there is no explanation.

You have, obviously, added some extra hardware that you didn't define, and written some code, probably using libraries that you did not post links to, that you didn't post. You can't really expect help, having omitted so much useful information.

3

@PaulS: what do you need more? library: mudbus, mentioned in my first post.
Hardware: UNO & ethernet shield, I thought that "tcp" was clear enough

4

what do you need more?

Links to the hardware you are using.
Links to the libraries that you are using.
Your code, in code tags.

5

So you have placed +70000 posts over here and you need a link to a known library (mudbus), and a link to known hardware (UNO and ethernet shield)?
Don't get it, what is there so hard about it? Is it the fact that I am a "newbie"? You are not a help at all, so let the room for people who try to help.

6

So you have placed +70000 posts over here and you need a link to a known library (mudbus)

Well, see, the thing is the modbus library might be well known, but I have no idea where you got the one that you are using, if that is what you meant. Personally, I've never heard of the mudbus library, and I have no idea where you got yours.

and a link to known hardware (UNO and ethernet shield)?

No. I assumed, incorrectly apparently, that mudbus was a typo, and that you meant modbus, which is typically used with extra hardware.

You are not a help at all, so let the room for people who try to help.

Will do.

7

bartmarchand:
So you have placed +70000 posts over here and you need a link to a known library (mudbus), and a link to known hardware (UNO and ethernet shield)?
Don't get it, what is there so hard about it? Is it the fact that I am a "newbie"? You are not a help at all, so let the room for people who try to help.

Which version of mudbus?
Which version of the ethernet shield?
Show your code.