This is in response to a question posed about using an external 24v PSU to power motion control and the C3D mini controller in a K40 instead of using the 24v from the stock K40. This info can be found in the documentation for installing a Z and/or A axis but is pretty far down in the doc.
It is important that the +24v from the laser power supply be disconnected and not used. It is also important that the grounds of both power supplies reference the same ground or else the laser won’t fire properly.
Thanks to Sean Willmott for the image 🙂