I have done a few PLC system drafts – one based on Raspberry PI, a second larger one and a 3rd based on distributed components. The pure PLC system was “ok”, but it was a bit larger with the bus than I expected. Looking at some of my 50x20mm designs I wanted to try a 50 x 50 mm design where we plug in a CAN/RS485 bus. The objective is to make a component based system that is very small.
The idea for this came as I stacked my CANUsb adapter and small motor controller (50x20mm) together for fun – I might even use that small format, but I think 50×50 is better. Worth a try.