Gmodbus over TCP Server

[Trinity32244]

Wondering if anyone has a quick example implementation of this working.  The demo file works fine.

I am having issues getting the modbus server portion working.  Here are the steps I am taking in this order

Single run

I open the TCP Connection

I initialize the listener

In the loop

Then I take the listener_ID created and listen_for_connections with that ID

Then listen for requests

It seems to have an issue with the listener_ID created because that is the only variables I am taking into the "listen_for_connections"

Attached the error, initialize, and running code

Initialize Code

Running Code

Error

 

 

 

   

[Mathilde38 · Accepted solution]

Hi,

In the modbus server code, you must use the "Initialize Listener" and the "Listen Connections" functions (see attachment).

The port number must be connected to the first input of the function "Initialize listener"

Hope this helps!

Mathilde

[Trinity32244]

I really appreciate the help and your example worked.  I can't figure out why when I try to organize it a little differently it stops working.  Looks like it gets hung up after the initialize listener.  I can work around it since you helped me get the basic connection code but have other reasons for organizing it this way and can't see the difference between what you sent and the execution of the other code.  Thanks again in advance

[Mathilde38]

The second case structure must be executed after the first, otherwise the local variable is not initialized.
In your code, the 2 structures are not sequenced.

[Trinity32244]

Thank you.  I did try that previously in my main code and did not work using a flat sequence structure wrapped around the case structures.  I revised this example to include as well and still gets hung up with error 56 like previously.