Arduino modbus communication


I have an arduino UNO and I want to connect it with a power analyzer. The ouput of the power analyzer is RS485 (modbus protocol). Especially the power analyzer is the Merlin Gerin PM9C. I have the Modbus register list of the power analyzer and I want to read some of these registers. Has anybody help me about the program?

Thank you in advance.

There is a MODBUS library available for arduino (in the archive section). There is serial support but you would need read up on the comments because I believe that there is a short coming with the arduino serial library when used with MODBUS. You should be able to use an RS232 to RS485 converter from B&B electronics.

If you search online there is software (trial/freeware) to test communication with the RTU as well.


The Free Modbus Scanner utility from (Windows Only) Works good for testing Modbus TCP and RTU.

Hi, Im having trouble sending modbus command over TCP from my arduino. Can anyone assist me please! I am not using the Modbus library but rather trying to send the bytes array as char's. I am new to Modbus and not sure how to trouble shoot. Thanks


1) don't ask a different question in an existing thread. Open a new one.

2) this is not the correct forum section. Try in Programming Questions...