Quote Originally Posted by JAZZCNC View Post
But if you want to be truely protect your machine and your self then you ought to look at using a hard wired E-stop that kills the power rather than just tells the software to stop. Software driven E-stop is NOT safe.
Another way is to make the E-stop switch interrupt the stepper motor step signals (resistor + switch to ground would do it, or better an AND gate on each), or use their enable input if they have one. That way the motors remain powered upon e-stop and make sure the axis' doesn't move. If you just cut the power to the stepper drivers then there's a very slight chance they may be damaged (but then it's an emergency after all, so that shouldn't matter?), but more importantly the motor could keep spinning for a bit due to it's inertia, or gravity with the Z-axis. I once had a power cut whilst my machine was cutting aluminium and it caused the cutter to plunge into the material and shatter - the Z-axis dropped due to gravity.

Having said that I've not bothered with any of this :whistling: ... but that's not reason for anyone else not to.