Modbus Serial on Moxa UC-8100A-ME-T always connecting

So as the title says, I’ve got a Moxa UC-8100A-ME-T that the particular model we were able to find in stock only came with ThingsPro, so we installed Ignition Edge on it as well. While the device is very slow to boot and run, everything eventually starts working except the Serial Modbus RTU connection. The status of this connection after a reboot just says “Connecting” forever which my understanding is that means it cannot open the serial port connection.

If I edit the connection and just click save without making any changes, it goes to “Disconnected” and then immediately “Connected” and it starts communicating. Which tells me it just closed the serial port and re-opened it to reconnect. I saw there’s an option to try to reconnect after 3 timeouts, but this is evidently not happening or I would think it would fix itself.

Anyone have any ideas as to how to get this to reliably connect after a reboot?

I ended up being able to fix it by modifying the Ignition service file to start after the Moxa Modbus Gateway service. I believe there’s some settings it sets on the port to configure it for RS-485 2-wire (it’s set in ThingsPro, but some service controls the port), so once I set it to start after that service instead of, it has worked twice in a row from rebooting the Moxa.

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