Just in case my query is not clear enough, the question is more about the serial ports. As most board come with only 1 serial port, I see the MEGA has 4, the RS232 serial connection from the inverter will use 1. My novice thinking is that although the Current Cost cable has a USB plug on the end, I won't be able to plug it in to the Arduino USB and read data from it as there is no driver, my thinking is that the output will need to go to a serial connection on the Arduino.
Conclusion, 2 UNO boards or 1 MEGA or is there a shield to provide the extra serial needed. Or am I completely wrong..