Re: [CAD_CAM_EDM_DRO] Maximum frequency of printerport and EMC

PMeinhard@... wrote:

> Hello !
> Its now the first time that I´m trying to use the g320 Geckodrives.
> Until now I used stepper drives 1/8 Step and Motor-resolution 1.8
> degrees. As
> software I used DINCNC. The max. velocity my mill reaches is 8m/min
> with 5mm
> skrewballs. If I figured out correctly that means an output-frequency
> of 43
> kHz. Now the servo-motors I´m going to use have DROs with 500 lines.
> Perhaps somebodey can help me with this :
> 1.) is it right that these 500 lines will be interpolated to a
> resolution on
> 1/2000 turn of the motor ?

Yes.

> 2.) I think the maximum Output-frequency of the printer-port depends
> on the
> processor. But what is reachable with a AMD-K2-300 ?

It is not easy to figure out. It depends on the type of chip used for
the printer port,
the mode it is set to, and the bus it is interfaced through.

> 3.) how does EMC limits this frequency ?

EMC decides to sends a step pulse, or not send one, every cycle through
the freqmot
code, which is scheduled every so many microseconds. But, not all of
that is usable.
If freqmot is scheduled every 100 uS (or 10 KHz), the jump from stepping
every
200 uS to every 100 uS would be too great for the stepper motors to
follow. Now, a
step-to-servo drive would have some smoothing imposed by the drive's
logic,
so maybe that would be work OK. You also need to know the maximum
frequency
the step-to-servo drive can accept.

Jon