It is the main. I bouth 2 of these inverters
And want to parallel them
The one inverter firmware is 52.02 and the second inverter is 74.02. I bouth them a month apart. I started with the one with the 74.02 firmware and after a while the inverter went black and only saying 32!. Black screen. And it doesn't want to respond. It looks like the inverter had the wrong firmware from the start. I bouth it with that firmware one it.