ProXR relay expansion with second controller board

My project recently went from needing <16 relays to needing 26. I already have a 16-relay ProXR controller board and a spare (both with USB communication) on order that should be arriving soon-ish.

Is it possible to make one of the relay controller boards act as an expansion board for the other relay board? And, if it doesn’t work like that, could I instead hook both controller boards up (via separate USB connections) to the same computer, and command each board individually? Or would they both report as the same serial port, and I would need to make one board a different type of communication, like ethernet?

I do intend to get actual relay expansion boards; these would just be a bandaid fix until the expansion boards are ordered and arrive.


A ProXR board cannot act as an expansion board. For that you must have an XR board.

You can connect both of them to the computer over USB however and control them individually. They will each mount to a different virtual Serial/COM port so you can direct commands to each board over their unique virtual Serial/COM port.

Thank you,

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