On Tuesday, February 14, 2012 02:51:18 PM Peter Blodow did opine: > Gene, how about drilling those holes, if you don't need more resolution > than that. Even simpler: punch them with a paper (document) punch (don't > know what the term in english is) in a straight piece of sheet metal. > > Peter
I thought of that Peter, but round holes would require more precision in mounting each of the slot detectors. So a hole turned into a slot, if I get it all corralled, will allow the interrupters to be mounted on a pcb which can be mounted fairly rigidly, in essentially a straight line, with A/B hitting two slots (actually about every 3rd slot since they are closer than the opto stuff can be) and the Z interrupter, sitting the same spacing away so its effective radii is larger and catches the outer index slot only, about .1" outboard of the main slot circle, should give something that is workable, and a whole lot more rigidly mounted than making 3 teeny little pcb holders that can get knocked out of whack screwing the timing so much easier. The idea is to set them perhaps 50 thou proud of the pcb, get the whole thing mounted, and with my dual trace scope, bend them a few thou sideways to arrive at a near perfect quadrature output signals giving 2 degree accuracy for the A/B signals. When that is done, then the bolts thru the opto's ears can be snugged up to firm up the position. The mounting holes in the board are oversize to allow this few thou of fudging. Then the Z signal logic s/b set to detect only an edge detected for a given A/B logic condition, and it will then be adjusted a few thou to put that edge dead in the center of the A/B condition defined. I haven't asked how to do that yet in the hal file, but I figure its likely only a line or 3 of hal code. Baby steps. :) The document punches here would make holes about 5x the size needed, so that would not be a workable solution given that I only have a small section of a circle whose radii is 2.3" at best to contain this. Perhaps 2.3" of pcb length, height determined by the bearing retainer nuts to face of spindle housing, approximately 1.1" in this case. The encoder wheel itself will be trapped between the spindle bearing lock buts. 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) My web page: <http://coyoteden.dyndns-free.com:85/gene> Karl's version of Parkinson's Law: Work expands to exceed the time alloted it. ------------------------------------------------------------------------------ Keep Your Developer Skills Current with LearnDevNow! The most comprehensive online learning library for Microsoft developers is just $99.99! Visual Studio, SharePoint, SQL - plus HTML5, CSS3, MVC3, Metro Style Apps, more. Free future releases when you subscribe now! http://p.sf.net/sfu/learndevnow-d2d _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
