Hi @FrankBritten ,
This post gives you some info.
But please pay attention to a difference that UR robots only act as “server” in Profinet but could be “client” or “server” in Modbus TCP so please be sure that you want the robot to be a server or client.
According to your description, I guess your robot should be a client to send requests to your stepper/ servo motor, right? If so, your robot cannot be a “client” when using Profinet protocol.
Thanks