Quote Originally Posted by EddyCurrent View Post
There is a ‘pause’ pushbutton that sends a ‘FeedHold’ signal to Mach3, it also stops the VFD.
To recover from a stop or pause condition a ‘reset’ button is pressed which also sends Mach3 an OEM signal to activate its RESET button and the VFD powers up again.
Eddy don't do that has when you "Feedhold" you won't want the spindle to stop spinning. It could still be in the material which would cause tool damage.
Also When you release "Feedhold" Mach won't start the Spindle without an M3 command or OEM code to turn it back on and if you "Feedhold" chances are your in the middle of a job and just want to pause for something like clearing chips etc. . . That's the point of "Feedhold" it's not to be used for Emergency or any Safety feature.

Now has to the rest of the Limits and E-stop best way debate then it's Simply down to preference.
I prefer to have E-stop Buttons Kill power to everything. Limits I have separate and just have kill Signals to drives and Send Signals to Control to stop the code.
If drives have Fault signals like AM882 then they are wired in series with Limits and just Kill signals and inform control.

Feedhold is not for this purpose and shouldn't be used has such IMO. In Mach's case it also doesn't stop instantly either has it has to clear the Look-ahead buffer first so can't be relied upon to stop quickly.