E-STOP Circuit - will this cause any problems?

[JAZZCNC]

It's a PCPPS V3.0 board. Doesn't appear to have any E-Stop contacts on it. My thinking is that if I kill all the AC devices, then the 50V supply to the steppers will also be killed which should be as safe as it can get?

It does but it's not shown has E-stop and is just an input. Any input can be used for E-stop and just setup in control software to watch this pin.

It would stop the machine but you would lose position and not be able to restart the job from the same position easily. I dont have any experience with this pcb but I would think that one of the inputs would be able to be configured as a estop sense so that the software can recognise an estop signal.

After any E-stop It should be Assumed that your out of position due to inertia pushing.!! That's why home switchs make it easy to get back in position.

Must admit I hadn't really considered maintaining position in order to restart as I assumed that an E-Stop would be in emergencies only because something had gone drastically wrong. Would it not be more accurate to re-zero the tool because it would most likely overrun slightly when the E-Stop is activated? Plus a tool breakage would probably require manual movement of the Z-axis in order to replace it.

Yes exactly what should be done after any E-stop which has occurred at anything other than very low feeds.

What you should really be doing is Mechanicly killing either signals or Electrical connections to devices and not relying on software to do it.

So thru relay contacts either kill the Enabel signal to drives or the power.? If you just kill the enable signal then the drives will stop but remain powered so keep there holding Torque. (Position will still have been lost.!) Personaly I kill the power to the transformer has I want the power shut down just to be extra safe.
Then at the same this happens the control software should be informed thru the input used for E-stop telling it to stop the code.

The BOB and PC should be left powered and out side the e-stop circuit.

Any other Powered Devices like spindle, Coolant pump or Vacuum should be shut down thru killing power Via Relay contacts. Again signalling to control software thru inputs.
Any device powered by VFD should be left powered but stopped by breaking Run signal thru a relay contact.