I would Like to connect with FRonious solar Inverter through MODBUS TCP with arduino to READ and WRITE register value only. I want to set Arduino as Master and Inverter as slave and I want to use only two functions "Read Holding Registers" and "Write Single Holding Register" function code '3' and function code '3' respectively. Is there any good and working Library available for these? and also an example.
Have you looked on sourceforge.net? There are a number of projects there for MODBus TCP that may help you, even if the code isn't exactly what you need to write.