you connect the PA2 via USB if you want to use it stand-alone. if you want to control it via Aquero you would not connect PA2 USB, but connect the PA2 to the Aquero via Aquabus.
if you have more than one PA2, they need to have unique ID's. To change the ID's you need the old Aquasuite software and the PA2's must be connected via USB. Once you change the ID's you can disconnect the PA2 USB.