On Thursday 15 February 2007, Peter C. Wallace wrote: >On Thu, 15 Feb 2007, Gene Heskett wrote: >> Date: Thu, 15 Feb 2007 15:44:32 -0500 >> From: Gene Heskett <[EMAIL PROTECTED]> >> Reply-To: "Enhanced Machine Controller (EMC)" >> <[email protected]> >> To: [email protected] >> Cc: Jon Elson <[EMAIL PROTECTED]> >> Subject: Re: [Emc-users] Hardware step generator for 5I20 >> >> On Thursday 15 February 2007, Jon Elson wrote: >>> [EMAIL PROTECTED] wrote: >>>> "Peter C. Wallace" <[EMAIL PROTECTED]> wrote: >>>>> Step/DIR or quadature output selectable per generator. >>> >>> My UPC has had quadrature output available since I developed it. I >>> don't think more >>> than one user actually used the feature, and he was using an absolute >>> minimum >>> driver, just power transistors. But, yes, it seems to have >>> significant advantages >>> over step/direction! >>> >>> Jon >> >> Generally I have to agree Jon, as the smoothest, most accurate mouse >> any of us has ever used was the decoded quadrature output amiga mouse >> of yesteryear, but it comes to mind, how does one handle the >> microstepping when using the quadrature signals if you can't step back >> and forth through the lookup table of desired currents using that? > >Quadrature is just an alternate way of taking steps (or microsteps) in > either direction. It has the advantage that it does not have the > direction --> step setup time problems that step/direction counters > suffer from. This is because is it a 2 bit Grey code where only one bit > can change at a time.
True. OTOH all changes are relative to the last one too, so there can be a potential loss of "where am I" info if this is not tracked in the generator and used as feedback. OTOH, if the 'index' is set at HOME time, then it becomes linked to the individual position at the moment rather than some fixed and arbitrary position that may be up to 4 steps away in the case of using hardware generated index pulses. I could definitely like that idea. :) > >> That would also seem to restrict you to 1/4 step resolutions unless >> the lookup table was two full cycles wide. Then one almost needs an >> index pulse too... >> >> Or am I miss-understanding the actual implementation? >> >> -- >> 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) >> Yahoo.com and AOL/TW attorneys please note, additions to the above >> message by Gene Heskett are: >> Copyright 2007 by Maurice Eugene Heskett, all rights reserved. >> >> ---------------------------------------------------------------------- >>--- Take Surveys. Earn Cash. Influence the Future of IT >> Join SourceForge.net's Techsay panel and you'll get the chance to >> share your opinions on IT & business topics through brief surveys-and >> earn cash >> http://www.techsay.com/default.php?page=join.php&p=sourceforge&CID=DEV >>DEV _______________________________________________ >> Emc-users mailing list >> [email protected] >> https://lists.sourceforge.net/lists/listinfo/emc-users > >Peter Wallace >Mesa Electronics > >(\__/) >(='.'=) This is Bunny. Copy and paste bunny into your >(")_(") signature to help him gain world domination. > > >------------------------------------------------------------------------ >- Take Surveys. Earn Cash. Influence the Future of IT >Join SourceForge.net's Techsay panel and you'll get the chance to share > your opinions on IT & business topics through brief surveys-and earn > cash > http://www.techsay.com/default.php?page=join.php&p=sourceforge&CID=DEVD >EV _______________________________________________ >Emc-users mailing list >[email protected] >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) Yahoo.com and AOL/TW attorneys please note, additions to the above message by Gene Heskett are: Copyright 2007 by Maurice Eugene Heskett, all rights reserved. ------------------------------------------------------------------------- Take Surveys. Earn Cash. Influence the Future of IT Join SourceForge.net's Techsay panel and you'll get the chance to share your opinions on IT & business topics through brief surveys-and earn cash http://www.techsay.com/default.php?page=join.php&p=sourceforge&CID=DEVDEV _______________________________________________ Emc-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/emc-users
