I actually am already using 24 volts with relays because the limits also send a signal to my servo amplifiers. The cnc machine is in another room from where the computer is for safety, noise and cleanliness reasons. The ground looping is something i've been looking into, and I'm finding it hard to get a plain english explaination as to how to check for it quickly. It reads like a lot back to future, flux capacitor, unhappy-doom. If anyone can help with a quick way of checking that'd be great. The problem with checking is the wires are in the wall and the ceiling so it's hard to recheck the wiring. The cables are not shielded, not for the limit switches to mach anyway, but since the noise was expected, I was really just hoping low pass filtering would fix the problem. Also, I was wondering if anyone, most likely the admins etc. could tell me more about the way the debouncing is implemented. If I had to guess I'd say it wasn't really done in low pass filtering kind of way (I mean mathematical low pass filtering) and done more in an ad-hoc sort of easy fix way.
Anything, no matter how small, will help.