Re: [CAD_CAM_EDM_DRO] Re: New Article Posted

Phil Mattison wrote:

> > So anyone using these boards will need to turn OFF microstepping, OR the
> > auto current and noise reduction. Can't use both without losing steps...
>
> That is correct, assuming you consider half-stepping not microstepping. Step
> divisions greater than 2 (the default) are not recommended for the 7062 in
> sync mode. For most applications using the PC parallel port, the required
> pulse rate would be too high anyway if you used higher microstepping rates.
>

Do you have some more information about this? I was running 8x
microstepping from my computer parallel port on a HCNC controller and
never had any issues. Going up to the next level (16?) gave some
problems when jogging, it seemed like that was beyond the rate that the
parallel port could handle. There was some delay (0.25-0.5s) between
releasing the jog keys and the axis stopping.

There was a definite advantage to 8x microstepping over 4x or
half-stepping on my Taig mill. I was able to run acceleration at
200,000 Hz as opposed to less than 1/10th that with 4x.

> I don't see where there is all that much to be gained anyway by high
> microstep rates in this case. The extra efficiency is trivial.

In my case there was a huge performance difference. Naturally it
depends on the characteristics of the machine, but I'd not like not
having the choice.

I'm curious about the problem with sync mode and lose of steps in
microstepping mode. Is this as a result of the reduced holding torque
at non- full or half step positions? I always wondered how it was that
the computer could run with the controller in microstep mode without
knowing where the full and half step positions where. It always seemed
to me that it would be highly likely to stop in positions the stepper
couldn't hold, possibly resulting in lost steps.

Dave K