If you are using a USB to RS485 adapter you are not running a USB cable to your device. These adapters generally don't have a USB cable at all, and are just a dongle you plug into your computer's USB port. You then run a RS485 cable from there to your device. As to speed, I'm pretty sure USB is quite a bit faster than RS485.
I have previously used 485 dongles but I think the mesa board connection is a cleaner wiring solution. I have used mb2hal but hm2-modbus is much easier for me.
I also found hm2-modbus/mesa refresh to offer much faster refresh than hm2hal/USB dongle which was important with some spindle calculations I was using to calculate gear ratios.
My advise is get the correct firmware and enjoy the cleaner wiring, easier message setup, and faster response with the mesa connection.
Last edit: 3 months 1 week ago by jtrantow. Reason: Clarity
