Andrew, You have all the tools at hand, it looks like. That print out is an excellent guide. Vaisala does a nice job with documentation.
I'm no protocol expert, but having the voltage to the WXT means it will run. The three output wires include a ground, so the receiving unit does NOT need any connection back up to the power from the solar battery you mention, just the three wires. I run RS232 and RS 465 (I think those are the numbers) and I just afix them to the three terminals on a serial to usb dongle that I use for a Win10 PC. I have a RaspPi system running with an IP address to a Rainwise, and after telling WeeWx (in the station driver) where to look, WeeWx just goes out and reads the incoming data stream. I will take a look at the WeeWx WXT driver to see if there is much in the configuration header, but I think you are just about ready to roll. I would wire the M12 pins to the RaspPi (I don't know if there are multiple to choose from, that's where the configuration on the WXT configuration in WeeWx comes in) and it should just listen to that input and start parsing the string once it gets a start location on the input. I know it does that for another type of situation I have too, so I wonder if you are overthinking it, just as I did to start with. The final thing is to use your WXT configuration cable and software to make sure that you have chosen the type of output you want, and that it is a constant output, no polling, and again I didn't open up the manual yet to look, that may be the only way that the SDI12 runs, maybe not. I had one configuration early on in which I had it set to poll and of course the weather display software didn't know to send a poll request, and the WXT was sitting waiting for a request to send and nothing happened. You sure can just wire it and see how it goes, and have the WeeWx station set, but I think you said you already have data flowing in, that it was working with a different interface? I have to run, will promise to look this afternoon to see if I can make sure the advice I have given you is OK, and that the WXT configuration is as you've said you have and needed. Dale -- You received this message because you are subscribed to the Google Groups "weewx-user" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To view this discussion on the web visit https://groups.google.com/d/msgid/weewx-user/a9062cda-f05e-d352-4c0b-4a913b7252cf%40charter.net.
