Using MODBUS_RTU function block in Codesys

[tanaya]

I want to extract tag/variable values from a Mitsubishi PLC using MODBUS RTU protocol through the serial port.
I am using Codesys for programming the PLC.
Can anyone tell how to establish the mapping between the tag names and the MODBUS addresses in Codesys?

Thanks in advance..

 

[goghie]

As I know Codesys and Mitsubishi are going together only if you have iQ C controler (Q06CCPU-V-H01 or Q12DCCPU-V). If you don't have some of those two CPUs, you will have to do classical programming and you will have to make function in Mitsubishi CPU (Modbus Slave) and to program your Modbus Master to read it. Modbus communication is not tag based, but memory address based (see www.modbus.org).