I finally assembled my first prototype box using a 3D printed panel. The first change is that the front had to be reduced to 5 x DSUB9 connectors because I needed extra space between them for the connectors in front – even 5 might be ambigious, but we will see then the canles w/connectors arrive. In this case I just removed the aluminium panel and replaced it with a 3D printed plastic one for prototyping – I will get the aluminium mounted later. I might be able to fit the 6th DSUB9 on the back.
This next picture is just a mock-up as I added 4 empty boxes to illustrate a stack. In this case you connect all 5 using the CAN or Ethernet on the back and you have five boxes with different IO content on the front.
This can act as a system on your desctop, a PLC in a cabinet or a mobile PLC distributed on a vehicle. You can add as many modules as you need – no, real limitation and they can form distributed nodes to make the best use of available space.