On Saturday 03 October 2009, Steve Blackmore wrote: >On Fri, 02 Oct 2009 15:24:24 -0400, you wrote: >>Page 5 and 6 show it but not at a good time scale, page 7 from the base >>thread sample shows it very clearly Steve. Noise. Until that is gone >> (and encoder A output could have a closer to 50% duty cycle too, I'd >> almost return that one in fact if its sealed and non adjustable), it >> isn't going to work, not even if we make sacrifices. :) >> >>I have to assume the encoders cabling is shielded, and the shield ends at >> the encoder so there is no connection via the shield to the machine by >> way of how the encoder is mounted and driven. That would be what we call >> a ground loop, and that is usually a no-no. > >Thanks Gene, that gave me clue and I found it - The encoder cable had a >strand from the shield touching the plug at the controller end. Much, >much better now, but still has the odd glitch, from where I don't know. >disconnecting all the grounds didn't get rid of it. > >As for the 50% duty cycle, can't do anything about that other than >replace the encoder. > >But - running at slow speed it's MUCH better, and running my test 1.5mm >pitch test file at my normal 700 rpm it's not noticeable at all. > >Have a look at the difference :) > >http://filebin.ca/brcenc/encoder.pdf > That looks better, but something is still giving the encoder.0.velocity a big kick occasionally. One page one it almost corresponds to the single pulse in the bottom, white trace that I don't see a caption for, and looks like its quite close to the edge of the non-50% A trace. Except for that big spike, which corresponds to a single pulse, not a dual pulse, in the bottom trace for each half cycle of the encoder b signal.
The expanded version on page 6 looks as if its working there. > >Steve Blackmore >-- > >--------------------------------------------------------------------------- >--- Come build with us! The BlackBerry® 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/devconf >_______________________________________________ >Emc-users mailing list >Emc-users@lists.sourceforge.net >https://lists.sourceforge.net/lists/listinfo/emc-users > -- 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) The NRA is offering FREE Associate memberships to anyone who wants them. <https://www.nrahq.org/nrabonus/accept-membership.asp> Simon: "It was either that or the National Anthem. Reports vary." --Episode #14, "Objects in Space" ------------------------------------------------------------------------------ Come build with us! The BlackBerry® 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/devconf _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
