I didn't want to muddy the water by hijacking this thread .
I get that using NO and NC switches both have their place depending on the system. And I don't know enough to argue one over the other for any certain application.
But recently, I ran across information where it was said that using opto-isolators (optocoupler, photocoupler) was the best way to prevent noise in wiring for a CNC.
What's your thoughts on using opto-isolators for this purpose?