Re: [CAD_CAM_EDM_DRO] Re: Servo hardware

caudlet wrote:

> --- In CAD_CAM_EDM_DRO@yahoogroups.com, "grd750" <grd750@...> wrote:
>
>> Will this system be able to remember its position if the servos fault?
>> The ability to restart from a fault would be really realy nice.
>>
>>
>>
> Usually if a servo faults it already has lost position. The control software is in charge of knowing where the toolpath is SUPPOSED to be but if the error is great enough to fault, do you really want to restart from the wrong position? The best thing is to determine what caused the fault in the first place (or it will just do it again) and then reestablish table zero and restart the cut from an accurate position.
>
>

This is true of step-servos like the Gecko 320. It is not true in
systems with position feedback to the computer, such as my
Universal PWM Controller and PPMC boards. These do not "lose position"
when something binds up, they only lose the ability to maintain the
commanded position. Yet, they still know exactly where the machine is.
So, when the jam is cleared, you can reliably restart from the CORRECT
position.

Jon