Read Internal Registers of RS485 I am trying to interface sele EM2M, I am using Arduino Mega with RS 485 module. I want to read the internal registers I am using ModbusMaster library. The data which I want to receive is in the internal registers but I am not getting how can I read Internal registers. When I use other software to read data I am getting the out 
I also wanted to know the difference between Internal Registers and Holding Registers
Another questions how are the frames formed for communication in rs485 from the above image I can understand 01 04 but from where do they get 00 1A please explain the same.
The RS485 has no internal registers, all of that is in your target unit. Hopefully the instructions for that will tell you how to do it.  Start by getting simple communications working then slowly progress from there.