On Wed, 9 Jan 2013, Chris Radek wrote: > Date: Wed, 9 Jan 2013 11:54:33 -0600 > From: Chris Radek <[email protected]> > Reply-To: EMC developers <[email protected]> > To: EMC developers <[email protected]> > Subject: Re: [Emc-developers] proposed patch for v2.5_branch: correct ferror > calculation > > On Wed, Jan 09, 2013 at 08:13:05AM +0100, Michael Haberler wrote: >> >> This patch makes the behavior of motion configurable by the new >> motion.ferror-mode pin. > > I recall there was some debate over whether this change was right or > wrong, so I am glad to see it as an option if it makes the behavior > better for some folks. Thank you for doing the work. > > Have you reports that this helps a real machine work better? >
Heres a couple screen shots of a torque mode drive with ferror-mode set to 0 and 1 freeby.mesanet.com/ferror0.png freeby.mesanet.com/ferror1.png Note that ferror mode 1 does not improve the tuning, it just does not indicate (and error out on) bogus ferror numbers (with -velocity/sampleperiod added to real ferror) Note that the actual ferror difference is small here (~1 mill) because of the 6 KHz servo thread. At a 1 KHz thread rate the difference would be ~6 mills! > >> By default (unconnected or set to 0), behavior is as before. >> If set to 1, ferror is computed only after the new commanded > > The only thing I suggest is changing to a pin name that documents > the behavior as well as possible. This name only tells us it > changes something regarding ferror, which is not very informative. > It is not even clear from the name that it is a boolean choice. > > I don't understand the use case well enough to suggest something > with high confidence, but if it's relevant for torque mode loops, > maybe ferror-torque-mode, or if you want to describe that ferror > uses its guess about where the machine should now be if it's moving > in the expected direction, maybe ferror-use-expected-position? > > Chris > > ------------------------------------------------------------------------------ > Master Java SE, Java EE, Eclipse, Spring, Hibernate, JavaScript, jQuery > and much more. Keep your Java skills current with LearnJavaNow - > 200+ hours of step-by-step video tutorials by Java experts. > SALE $49.99 this month only -- learn more at: > http://p.sf.net/sfu/learnmore_122612 > _______________________________________________ > Emc-developers mailing list > [email protected] > https://lists.sourceforge.net/lists/listinfo/emc-developers > Peter Wallace Mesa Electronics (\__/) (='.'=) This is Bunny. Copy and paste bunny into your (")_(") signature to help him gain world domination. ------------------------------------------------------------------------------ Master Java SE, Java EE, Eclipse, Spring, Hibernate, JavaScript, jQuery and much more. Keep your Java skills current with LearnJavaNow - 200+ hours of step-by-step video tutorials by Java experts. SALE $49.99 this month only -- learn more at: http://p.sf.net/sfu/learnmore_122612 _______________________________________________ Emc-developers mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/emc-developers
