SO3 E-stop; Digital or AC Cut-off

What is the best solution for an E-stop on the Shapeoko 3? Using the digital header pins on the motion controller board (can’t seem to find any info as to what shorting the the e stop pins on the motion controller does in terms of gentle stop or immediate stop?). Or just hard wiring an AC E-Stop into the spindle and dc power supply, would this have any damaging effects on the motion controller and steppers?

The Nomad 883 E-Stop does not cut the power but does remove the enable signals from many of the chips in the internal controller. Things stop.

The Nomad 883 Pro doesn’t have an E-Stop… the power switch is the E-Stop.

I’ve used equipment where the E-Stop stops motion but leaves the spindle running (not the best), kills all actions but leaves the power running (good), and kills all power to everything (good). Based on generally used electronic design principals all equipment should not be damaged by the kill all power method - otherwise a power failure would be all too damaging.

Personally, if I think things are that critical that I have to hit the E-Stop, I want all activity killed. Dropping the power is fine with me, I have to reinitialize everything anyway; the stock is probably shot anyway.

@WillAdams is the SO3 person I would like to hear from. There may be some SO3 specifics that point to a preferred choice.


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I think E-stops should kill power to everything — spindle, motors, dust collection.

One of these days I’ll use my machine enough to justify purchasing one of these:

Of course, there was a lot of discussion of this, and what I could got captured to a wiki page: and there was an SO3-specific discussion.

I think i will go for killing power to everything as you say. I managed to get hold of a mains high power switch box from work complete with E stop and key switch (for the spindle)

apologies for the potato quality photo, I need a new phone!

Don’t you need a missile launch cover on the key? :joy:


Don’t tempt me! :grinning: