On Tuesday 17 December 2013 07:26:20 Bertho Stultiens did opine: > On 12/17/2013 12:23 PM, Gene Heskett wrote: > >> I wonder if this is anything like that? > >> http://www.youtube.com/watch?v=2SozZ7af3wg > > > > No, no resemblance to my idea, and TBT that driver would be dangerous > > unless its feedback does go into LCNC so LCNC knows it is not where > > LCNC told it to be. Cute demo yes but could you trust 9 of them to > > stay within a thou of the programmed path? Scary. > > But that is the point; if you do not have feedback, then you will never > be able to ensure that you are anywhere on the programmed path. No > matter what driver you use. If one axis is slowed down externally, then > all others need to be adjusted too. > > The real problem is, if the slowing force is reduced, who is controlling > the axis' (re-)acceleration? If the HW driver is (partly) autonomous, > then your controlling SW will always lag behind and create a larger path > deviation than if the SW has full control. I.e. reactionary vs. > actionary control.
Absolutely, that driver, even though its driving steppers MUST be treated like a servo, where if it hasn't the hangy downs to get there, the rest of the machine is slowed to match and the path tolerance maintained. Then the question turns into a which costs more question. And the fact that few if any of them are being used, at least on this list & worldview, pretty well answers that. If there were a distinct price advantage over servo's, you can bet your sweet we'd have been discussing and using them already. I've a limited info path, these two lists and haven't heard of them till now. Jon's foray into using encoders on steppers for feedback quite some time ago seems to have well defined the problems. Cheers, Gene -- "There are four boxes to be used in defense of liberty: soap, ballot, jury, and ammo. Please use in that order." -Ed Howdershelt (Author) Genes Web page <http://geneslinuxbox.net:6309/gene> Nothing happens. A pen in the hand of this president is far more dangerous than 200 million guns in the hands of law-abiding citizens. ------------------------------------------------------------------------------ Rapidly troubleshoot problems before they affect your business. Most IT organizations don't have a clear picture of how application performance affects their revenue. With AppDynamics, you get 100% visibility into your Java,.NET, & PHP application. Start your 15-day FREE TRIAL of AppDynamics Pro! http://pubads.g.doubleclick.net/gampad/clk?id=84349831&iu=/4140/ostg.clktrk _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
