Do you have a link to the X-Controller schematic?
They have it setup for Io(100%) is approximately 4A.
Rnf appears to be 0.157 ohms (3 parallel 0.47 ohm resistors)
Vref is limited to 0-1.95V
Where does Vin for the 5V power come from?
Vmot
Ok, I think I see where you’re going with this, but keep in mind that the diagram I used for the diode example is a functional diagram and not a circuit diagram. We don’t know what circuitry is tied to the VM pin.
Right, so spinning the motor, while powered off, will apply power to Vmot. That is also the Vin for the LM25011. If the voltage generated by the motor is sufficient, we’ll get 5v to the board.
Am I missing something?
See above edit.
Yes, but my experience is telling me that this is the case. Again, I do not have an X-Carve.
Just did a test with a Sparkfun Easy Driver and when I had the enable pin low (enabled) I could feel it enabling when I spin by hand. When I tied the enable pin top 5v (disabled), I was able to spin freely. The 5v power indicator LED lit up in either case. This was all done with a little Nema 17 and no controller or other power source. i know this is a completely different driver, but I suspect the principle is the same.
Well, I do. Interesting. You are correct. An aggressive movement of the gantry by hand generated 6 volts on the output of the power supply (basically through the driver to the power supply).
Which is why I’m suggesting to make sure $1=255. As soon as the back-driving voltage is high enough, the stepper will enable, forcing the machine abuser to slow down.
That’s not the issue. We were discussing moving the machine by hand when there was no power to the controller chip.
$1 does not come into play in that scenario.
Even though some voltage is being generated by the manual movement, It doesn’t meet the undervoltage requirements for the driver chip to function.
I would have to look in more detail to see if the 6 volts is enough to get a 5 volt output from the +5 volt supply.
[Edit] just might - barely
Input Operating Voltage Range: 6 V to 42 V
I skimmed earlier, I think it’s 8v.
Unless the action of moving by hand powers the driver well before any damage could occur.
Well, it’s been a good discussion and I learned some things.
I’m not sure that we are ahead of where we were when we started, but I think the bottom line is that it’s not likely to be an issue.
I wouldn’t recommend moving the system manually without power on, but I won’t be discouraging it either.
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Completely agree.
What he said 
, you guys lost me 20 comments ago but it was fascinating to read and absorb. Thanks!
Donnie
Good thing the laser uses a separate power supply.
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Yikes! Get a pull down resistor on that.
X-controller should work the same. Could be a problem there as well.
Most likely the DEMON too.
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This company has a new 3D printer with a interesting feature on it. A special button named “Disable Motors” which is used for when you need to move the print head by hand - without - damaging the stepper motor driver electronics. And you don’t need to manually turn them back on again. When you start a new print the motors are automatically engaged.
I have a switch on my X-Carve controller that disables the motors as well, but I have to turn it back on manually to re-engage them. (I am running the Gecko G540, not GRBL anymore).