Working in embedded software for aerospace is what drove me to make DiffPlug. When I built the Simulink differ, I spent a lot of time making it very general so that I could go after PCB schematics and layouts, some of the FPGA toolchain, etc.

I don't have any specific experience with PLC programming, but I bet some of DiffPlug could help your co-worker. The public API is still months from being stable, but I'd love to talk with your co-worker, I expect we have some shared interests. If he or she is interested, my personal email is ned.twigg@diffplug.com