Modbus communication to Festo CMMT

Good morning,

For me its the first time I´m working with a Robot. From the Robot I have to operate a Festo Stepmotor. The Festo Motor is connected to the Robot via Modbus. I added the CMMT as a Modbus device. On Festo the Telegram 111 is selected.
How do I communicate with that device? Is there any example, or a guidline on how to create the Read/Write interface?
As mentioned I´m completely new to this. To operate the Stepmotor at a PLC (which we are not using here) is super simple , but I don´t undertand how the Robot-Festo Modbus communication has to implemented at the UR.

I checked the manual “Modbus Register and Digital I/O -19252” and the “Using the Modbus TCP Client Interface of the UR Robot” but I´m not getting it.

I´m thankful for any support.
Thank you!

Greetings from Luxemburg.

Hi Kadams
I hope you are doing well.
I can share this with you in case you are stil interested in this topic, we are using CMMP instead of CMMT.
You can contact me at


Find more info and FMAS PSI:
→ EN

→ ES

→ FR