Modbus RTU and Danfoss

[Miguel Rojas Brenes]

Hello.

I want to communicate for rs-485 a plc unitonics m91 and  danfoos fc51.

I need to run, stop and change the frecuency for rs-485. I need help. Thank you

[Joe Tauser]

I split this request off of this thread, which contained a lot of information regarding talking to a Danfoss drive from a Vision controller-

 

It also had a post by me with detailed instructions on how to get started with the software and hardware tools needed to troubleshoot Modbus communications.

Miguel - start by looking at the Example Programs in the U90 software.  They're under the Help menu and there's one for Modbus Master.  You'll have to figure out which registers in the FC51 you need to write to.

If you do a little research and post what you find here we can help.  Also, upload any PLC programs you've done with questions.

Joe T.