> From: Chris Albertson [mailto:albertson.ch...@gmail.com] > Sent: April-28-20 6:13 PM > To: Enhanced Machine Controller (EMC) > Subject: Re: [Emc-users] A simple LinuxCNC system > > > > > *For a stepping motor driver with 10uStep per step that's still pretty > > well faster than it can actually turn. * > > > No, you missed the point. With 10 uS per cycle, the motor can step in > steps that are a multiple of 10uS long. So it can be 6000 uS or 6010 uS > but never 6011 uS per step. It is the step-size resolution. The pulse can > be raised or lowered on each cycle. I think the max step rates would then > be 20 uS or 50KHz which is faster than it can go.
Hi Chris, I think I didn't explain that well enough. A Gecko a 10 step per step drive. What is commonly called micro-steps. Perhaps I should have written it that way. As far as LinuxCNC goes, to me it appears the parallel port code given the steplen calculations there isn't a way to bring the step pulse low again during the same BASE_PERIOD interval which in the HAL file example is 24uS not 10uS. Therefore I interpret the step pulses to be twice the BASE_PERIOD time. > > BTW this only works because you have a very fast processor. If I'm > running a stepper motor using my $1 (yes literally $1) microcontroller chip > I can tell the hardware step generator the step period in units of 0.001 > uS. one nanosecond I get 10,000 times better resolution. I think the FPGA > based solutions do the same. That said, I doubt the nanosecond level > resolution of the step period is really needed. Will you share some code on how you accelerate from 0 to 15kHz stepping rate on your $1 processor? Thanks John > > > > -- > > Chris Albertson > Redondo Beach, California > > _______________________________________________ > Emc-users mailing list > Emc-users@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/emc-users _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
