bucknast:
...we have in house electricians who will design and validate the safety necessary electronics,...
...instead of a traditional PLC, or PCPLC setup.
Yes but that's exactly my point. The electricians have the skills to read the specs for the parts they need to install, and they follow those and do it right. The electrician doesn't have the skills or knowledge to design the device itself. But you're talking -about- designing 'a device,' which requires engineering skills and knowledge. Catch-22.
Personally, if my (economic and family business) life depended on it, I'd go straight for what works first time every time. The % cost of just the PLC as compared to motors, mechanicals, wiring, and labor is fairly small, as compared to the -potential- the cost of failure. The % of success of the traditional PLC, happening very quickly is very high. The % of success designing an Arduino system, with all the -time- for leaning and experimentation involved is pretty high, but will take 20-40x longer. If you want to learn more about how to interface Arduino -and- use it in your business, this isn't the place for it.