If I recall correctly, Mitsubishi PLCs are programmed with GX Developer, that is CodeSys based software.
And Mitsubishi Robots are programmed with their own Teach Pendants, or with RT Toolbox, a desktop programming and simulation tool.
IIRC, there are a few different "hardware" PLCs that can be programmed using CodeSys -- Beckhoffs are one, I think. But CS's main selling point seems to be that you can use a PC as a full-up PLC (except for Safety functions).
I like CS, but in large part b/c it has permissive terms for the "trial" version (basically, fully featured, but limited to 2hrs of run time before needing a restart) and comes in very handy for R&D and experimental work when I don't have a "hardware" PLC available. Being able to whip up a quick soft-PLC that can use EIP, ProfiNet, EtherCat, ModBus, and OPC-UA in short order without spending any money is very handy sometimes.
I can't speak to Mitsubishi robots, but a quick Googling implies that Mitsu PLCs support Codesys. I don't think CodeSys would serve as a robot controller, but KUKA sells an option that allows you to program a SoftPLC directly inside the robot, running as a parallel task. It's possible that Mitsubishi might have a similar option for their robots.
