Peter Oakes goes over a Arduino based Industrial PLC system called Industrial Shields. If you are an Arduino programmer and are looking to incorporate your design into something that is a bit more robust this might be for you. I was thinking the system would just use some of the standard Atmel chips that are common in Arduino systems and just use the IDE for programming but it actually incorporates the real Arduino boards. Of course there is not much protection on the normal Arduino boards since that would add a lot of expense and for a quick and dirty project would not normally be needed.
The system comes with a modular DIN rail system which allows for module replacement and addition flexibility. The parts that are used in the system is high quality and looks to be built very robustly. Looks like everything is opto isolated to prevent an external fault from taking out your entire control system. Much of the terminal blocks are pluggable which also aids in fast module replacements. Only thing that looks a bit janky is the wiring harness that can be seen at 41:30 which seems like it could have been better designed.
“The brand is “Industrial Shield” and they are from a company in Barcelona, Spain called “Boot and Work S.L.”
One of the really cool things about these PLCs is that they are based on Open Source Hardware in the form of an Arduino Leonardo or the Arduino MEGA2560… yes the real thing, no modifications aside from providing an industrial strength interfacing circuits around them, wrapped up in a nice industrial DIN rail mountable package including full 24V operation, 0-10V analog in and out as well as isolated relay outputs and OPTO isolated digital inputs and outputs”