Which ModBus Function Codes does the ModBus client support

Technical Questions Robot Communication
1

I’m having significant problems getting the internal modbus client to talk to external modbus servers.

I can establish the modbus connection between the parts and the robot confirms that the connection is established. BUT I can NOT write any new values to registers in the external modbus server.

I’m getting a suspicion that the UR modbus client only supports a subset of the modbus protocol.

Can You list the modbus function codes that the UR implementation supports?

BTW. The device I’m trying to connect to is a FESTO CTEU-EP.

2

This help article has information on what function codes and exception codes the system works with, https://www.universal-robots.com/how-tos-and-faqs/how-to/ur-how-tos/modbus-server-16377/

I know we did some work with a Festo motion controller earlier in the year and I believe we struggled to get it working, in the end we returned it and used another solution.

3

Hi John, I’m trying to do the same thing as you. Did you succeed and if so, how did you establish the connection or how do you switch the valve terminal?