Am 21.10.2009 um 00:21 schrieb Steve Blackmore: > On Tue, 20 Oct 2009 23:26:27 +0200, you wrote: > >> several folks (including me) reported problems with threading - >> namely >> oscillations of the spindle-synchronized feed (G33 and G76), mostly >> with homebrew encoders. Most people looked at their encoders and >> signal properties. > > It's not only home made encoders, expensive commercial encoders have > the > same problem.
I figured sim-encoder signals would be cleaner than any hw encoder, and if the problem shows there, it should show with hw encoders as well; and it does, so the encoder make doesnt matter >> I dont fully understand the trajectory planner, but my gut feeling >> it's a control loop oscillation which gets excited with the encoder >> quantization/noise spectrum gets too close to the loop frequency. > > Neither do I, but I tend to agree that there is some other design > limitation that is not helping somewhere. I'm a CNC retard, so here's my question: where is the benefit in incrementally controlling the feed depending on continuous spindle position updates as opposed to just assuming the spindle angular speed stays constant for the next full revolution? it's a pity - I own a mill which sort of was designed as a Mach3 peripheral and it does rigid tapping fine with a 1 PPR optical reflex encoder on the spindle with Mach3 -- I do use a 5i20 so I dont think a high encoder PPR would be much of a problem here, but that leaves the parport folks in limbo -Michael ------------------------------------------------------------------------------ Come build with us! The BlackBerry(R) Developer Conference in SF, CA is the only developer event you need to attend this year. Jumpstart your developing skills, take BlackBerry mobile applications to market and stay ahead of the curve. Join us from November 9 - 12, 2009. Register now! http://p.sf.net/sfu/devconference _______________________________________________ Emc-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/emc-users
