Yeah, I didn't quite figure that out, and I'm done digging. Looks like a bit of a mess.
I realize that not java, or incorrect licenses on what exists of code on github less chance of that happening.
And there is always a gateway that can convert from one protocol to another.
But Ignition makes support for some protocols. So then I try to get support for a protocol we use.
And I'm in a market that I don't think many other ignition users are. We use Ignition in building automation.
Ignition works very well for visualizing buildings, ventilation systems, heating systems, etc. It is possible that even more people who work with building automation would have chosen Ignition if support for one of the main protocols was built-in.
Europe probably uses slightly different things than the USA.
As in support of Allen Bradley. 6 diffrent types.
I have never seen a Allen Bradley device. But that don't mean people don't use them. You can probably convert their protocols over to opc/ua, modbus or something else too.
I found this Java KNX project.
But it is GPL3. So I don't know if it can be used with ignition.
Nope.
OK, I realize that not all licenses are compatible