Re: PC based CNC system architecture

> >Wally K wrote:
> > If you would use the encoder counter card to count encoder pulses

are

> > there any special requirements for encoder resolution.
>

> Jon replys:
> None in a servo system, other than the resolution should be greater

than

> whatever position accuracy you want by a factor of ten or so.
>
> For steppers, I think having an encoder with more resolution than

the

> stepper could cause problems. But, we could put a dead zone in the
> control loop to prevent fast hunting. (The planned design will

cause steppers

> to hunt at a rate of one step every .6 seconds, as that is as slow

as the

> rate generator can go.)
>

Wally K.

For this dead zone in the control loop for steppers. Is this a
number in an EMC file. Or something on your control.

Also i do not understand your hunt rate. "to hunt at a rate of one
step every .6 seconds, as that is as slow as the rate generator can
go." maybe i am thinking of the wrong term. Is hunt rate different
than correcting for missing steps or encoder counts.

And, If i have a stepper system and want to add 1 spindle control
axis for my bridgeport to use for a VFD. Can your 4 axis servo card
be populated for 1 axis and maybe even a cheap DAC put on board. (i
think you said before the Burr Brown DACS are a little pricey, 4 of
these would probably add right up).


Wally K.