OK. 500kHz max step rate. Max micro-steps/step is 16. Standard stepper motor has 200 full steps per rev so that's 3200 steps/rev or 156.25 revs/sec at 500kHz max step rate which is 9375 RPM. Yeah right a stepper motor turning that fast. And their data sheet also states 200-51,200 micro steps in the same line as 16 micro-step resolutions.
I'd ignore the 50% duty cycle just like I'd ignore their max step rate. In fact I'd ignore StepperOnline for closed loop steppers and stay with AC or DC Servos. John > -----Original Message----- > From: Todd Zuercher [mailto:to...@pgrahamdunn.com] > Sent: October 25, 2023 8:59 AM > To: Enhanced Machine Controller (EMC) > Subject: Re: [Emc-users] Mesa Step Pulses? > > Gene, > > The drive is a "closed loop" stepper drive from Steperonline. > Here is a link to the doc. > https://www.omc- > stepperonline.com/index.php?route=product/product/get_file&file=388/CL > 57T_V4.0.pdf > > I've yet to actually power one of these up yet. (Still have a lot more building > to do before I'm ready for that.) But I don't think I'm going to be asking too > much of them. At this point I'm only hoping for at least 1000rpm from these > NEMA23 closed loop stepper motors. (If I can get them to spin faster great, > but I won't be upset if they can't do 2000rpm.) > > Todd Zuercher > P. Graham Dunn Inc. > 630 Henry Street > Dalton, Ohio 44618 > Phone: (330)828-2105ext. 2031 > > -----Original Message----- > From: gene heskett <ghesk...@shentel.net> > Sent: Wednesday, October 25, 2023 11:17 AM > To: emc-users@lists.sourceforge.net > Subject: Re: [Emc-users] Mesa Step Pulses? > > [EXTERNAL EMAIL] Be sure links are safe. > > On 10/25/23 08:24, Todd Zuercher wrote: > > Hello, > > > > It is my understanding that the step pulses generated by Mesa cards are > always the minimum pulse length set by for example > hm2_5i25.0.stepgen.00.steplen, only the space between the pulses is varied > by the step rate, is that correct? > > > > I was reading the manual for the new drive I was planning to use in my next > build and see that the drive calls a preference of a 50% duty cycle for step > pulse inputs. I am guessing that it may have something to do with how the > drive's pulse filtering system works, such that for maximum noise filtering > and step reliability having the pulse length be approximately equal to the > step spacing gives the best results. > > > > So my questions are; Would it be possible to make a Mesa card output a > 50% duty cycle step pattern instead of the current default pattern? And > would doing this even be worth the effort? > > > Do yopu have a link to that doc? > > In the drives I've played with using a function generator, a near 50% ratio can > help when pushing the drive limits, but generally the speed of the opto- > isolator is the ultimate limit, blurring the pulse into almost unrecognizable > signals, slowed by the response times of the opto device used. For real > dependability at 200 khz and up to the failure of the opto, usually around > 375khz, trimming a wee bit one side or the other might get a motor with no > load, just laying on the table some good, getting it upto 2000 revs but unless > the motor voltage is also cranked uo, torque to do actual work at that speed > is just a dream at 45 volts. > Some of the nextgen closed loop drivers can use 90-140 volts, overcoming > the windings inductance much faster, That makes it possible to make usable > torque at 3000 revs. Those higher performance transistors do raise the price > a bit. Particularly in the 3 phase versions. But they run like casper the ghost is > turning the cranks, Quiet. > > Todd Zuercher > > P. Graham Dunn > > > Inc.<https://nam04.safelinks.protection.outlook.com/?url=http%3A%2F%2F > > > http://www.pgrahamdunn.com/%2Findex.php&data=05%7C01%7Ctoddz%4 > 0pgrahamdunn.com > > > %7C0522ff7789484192c1e808dbd56d7fcc%7C5758544c573f47cebee96c3e0806 > fb43 > > > %7C0%7C0%7C638338438551181150%7CUnknown%7CTWFpbGZsb3d8eyJWIj > oiMC4wLjAw > > > MDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000%7C%7C% > 7C&sda > > > ta=GD9S6tywNNdc0N2LZQ6I10zMC0BZScL%2FKumvnpWyoz8%3D&reserved > =0> > > 630 Henry Street > > Dalton, Ohio 44618 > > Phone: (330)828-2105ext. 2031 > > > > > Cheers, Gene Heskett. > -- > "There are four boxes to be used in defense of liberty: > soap, ballot, jury, and ammo. Please use in that order." > -Ed Howdershelt (Author, 1940) > If we desire respect for the law, we must first make the law respectable. > - Louis D. Brandeis > > > > _______________________________________________ > 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 _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
