Re: [CAD_CAM_EDM_DRO] Re: UPS ... how do you find your way back?

JanRwl@... wrote:

> What I don't understand about this UPS bidniss with a stepper-run machine (no
> "absolute" encoders), if the computer is "kept going" during ten seconds or
> however long after a power-out, but the 3-phase 27 hp woodworking X-Y machine
> is not powered, how will the computer know it has merrily continued to
> command the machine to make moves it hasn't??? This seems to be a point no
> one has touched on! Jan Rowland, Old Troll, home-brewer of CAM he has no
> bidniss conjuring.

Clearly, in an open loop system, the stepper drivers have to stay powered on
by the UPS, or position will be lost. In a servo or closed-loop stepper system,
if the encoders are powered by the computer (or other battery-backed
power source) then the position will not be lost. My servo amps will generate
an E-stop contact opening if they lose power. My VFD will also open the
fault contacts if it loses power when running. So, the computer will know that
the machine stopped.

Jon