Quote Originally Posted by wilfy View Post
correct me if i'm wrong as i am also new to this cnc lark still but i thought limit switches were protection to stop the machine from travelling to far.. so if they are tripped the machine would just stop at this point hence making it pretty obvious which one has tripped?
Things like e-stops and limit switches are a little bit more involved then 'just stop'. Think about doing 50mph in a car and for some reason you want to stop quickly, do you cut all the power to the engine and roll to a stop or do you hit the brakes hard?

Computers are very, very stupid so not only do you have to hit the brakes hard you need to make sure that nothing else is telling the motors to do anything else and the switches/e-stop can't be overridden by any other tech trying to ensure that the machine keeps position.