Connection issues between Proface HMI and motor driver AZD CEP

[Guillaume MENIN 0]

Hi everyone ,

I need your help !!!

I am currently working on a project where I have to control a stepper motor (oriental motor AZD CEP) with a proface HMI.
To do this I use implicit Ethernet IP messaging.

The problem is this: when I change screens, I lose the connection between the two devices. 
After 20-30 seconds, the connection is reestablished.

I've already spent two days on it and I can't figure out where the problem is coming from.
Does anyone have any idea what's wrong?

If you need additional information or screenshots to understand, let me know.

Thank you in advance for your help.