I'm no electrical engineer (just mechanical) but I would like to apply some of my hobbyist experience to my job and implement various automated systems in an industrial (manufacturing) environment.
Traditionally, automation in the industrial setting consists of either engineered systems or PLCs. Engineered systems are too expensive and PLCs lack flexibility (and they can get pretty expensive as well).
I would like to replace traditional PLCs with more flexible, powerful, and cheaper Arduinos but I'm concerned about the Arduino's reliability. PLCs evolved in the industrial setting and are thus very rugged and reliable but how does the Arduino platform compare?
Assuming that proper measures are taken to protect the Arduino from mechanical and electrical damage, how reliable is the platform? Would you trust it to replace a traditional PLC that controls say a machine's safety interlock system to prevent people from getting too close to a machine in operation?
Edit: What about non safety critical systems? For example, introducing intelligence into say a fixture which a PLC would not be capable of?