Rocky,
My intent is not to confuse anyone but I would make sure that I was not using a green wire that might have been put in for safety purposes for the wire being a long term substitute for a neutral voltage return wire (main electrical entrance panel). In other words, the green wire may function but there could be a hazard created. It seems like if Class 2 transformer(s) are used there would be less risk & possibly no risk. A little bit of knowledge can be dangerous ... & I guess that is why you want someone here to verify there are no other potential considerations. Calling a qualified for your equipment electrician to your facility would be the best as he would be in a position to thoroughly examine all the connections. I remember once visiting with a high school classmate who became an electrician & he hooked me up to an electrician who specialized more in controls ... I remember his wise words ... not all electricians are good at controls.
Long term safety should always be properly considered!
Mike