Quote Originally Posted by Desertboy View Post
My only experience with microswitches and CNC style controllers are Arduino based but I do know the Arduino has internal pullup resistors so that microswitchs work from 2 wires (Unpowered) but when you use inductive sensors they need to be powered so you have to turn the internal pullup resistors off in the firmware (You also need to wire some resistors to drop the voltage from 12v to 5v so it doesn't fry the Arduino.) and make sure you have the correct firmware setting for NO/NC. I wonder if this could be related?

I have an inductive sensor for auto levelling my 3d printer bed and an aluminium print bed and fried 1 Arduino before I found this out.
Getting them to work as single NC switches is fairly easy on the CS Labs / Mach 3 setup.

Im trying to work out how to wire them in series and how to mix between limit / home options.

Another way is to wire something via the E Stop circuit for limit switches and not actually use the 'limit switch' pins available to Mach 3.