Quote Originally Posted by Boyan Silyavski View Post
Real life scenario today. Electricity stopped for a sec today, something with the fuse box or whatever. Flipped back the main interrupter at home, went to machine, hit "all go to 0" and after 3 min it was operational. It had not lost exact machine position .I had just to check if Z height is there correctly to be sure, as i have loaded 60 euro tool, All was there as it should be on place.
Boyan don't get me wrong here I'm not trying to put you or the controller down here but this needs to be said and made clear for sake of others reading what you wrote and thinking it will work same for them when chances are it won't and here's why.?

What speed was the machine traveling when power failed.? The law of physics dictates that inertia will make the axis continue on for some unknown distance if travleing at resonable velocity. So unless you have absolute encoders or Glass linear scales on the axis you will have lost position.

Now in your case you have Servo's which more than likely will have incremental encoders which don't retain there position when power is lost so they have not had any affect on keeping position. These controllers Also don't have positional feed back so equally it has no Clue to where the axis was when power failed.

So the fact you got back into position as nothing to do with the controller and everything to do with the fact your using servos which can accurately home. Probably using the encoder if using index pulse for homing.?
Steppers or Servo if traveling at any resonable feedrate position will be lost if poiwer fails. The function of getting back into Exact position as nothing to do with controller and everything thing to do with the HOME sensing type, be that encoder index or Home Switch.

This is no different to any other Controller be that PC based or Stand alone. The only exception is if your Encoders are absolute type or have Glass linear scales in which case the Servo drives are doing the work not the controller.