wait - couldn't you use a temp sensor and have emc adjust the encoder scale (or something like that) on the fly? calibrate it once and it should be consistent.. Then you could use emc2's leadscrew comp (for lead screw/backlash inconsistencies) + temp correction. (or am I just dreaming?)
just a thought. ----- Original Message ----- From: "Dave Engvall" <[EMAIL PROTECTED]> To: "Enhanced Machine Controller (EMC)" <[email protected]> Sent: Monday, January 21, 2008 02:53 PM Subject: Re: [Emc-users] more scales > The SONY website show some of their scales with coeff of expansion = > steel and apparently others that match who knows what! > MMS a couple of months ago show an approach where there was a shop > made gage that ran alongside the > long work pieces and was probed before each job to determine > expansion corrections. Not the easiest thing and > pretty expensive for a one-off but for long term production it will > work. > > Good luck. > > Dave > > > On Jan 21, 2008, at 11:51 AM, Jon Elson wrote: > >> Stuart Stevenson wrote: >>> >>> The scales are SONY scales with an MD10A interpolator on them. >>> The >>> interpolator gives a max resolution of .5 UM. .5 micrometers is >>> 0.00002 inch. I don't know what the interpolator is configured >>> for. It >>> can be configured for .5, 1, 2, 2.5, 4, 5, 10 UM. >>> >>> >> OK, then, that solves THAT problem. At .5 um you get 50800 >> counts/inch, which should be good enough for nice smooth movement. >>> >>> I have DAC output from the ppmc boards to the A/B ac servo >>> amps. I >>> don't have motion yet. I am a lot closer. We will try to determine >>> why >>> the amps don't output later today. >> Unless the ballscrews have a lot of slop, you should be able to >> make it run just on the linear scale. Maybe much over 2 >> thousandths of an inch would get to a lot of rattling or >> excessive use of deadband. I assume these amps have tach feedback? >> >> Jon >> >> ---------------------------------------------------------------------- >> --- >> This SF.net email is sponsored by: Microsoft >> Defy all challenges. Microsoft(R) Visual Studio 2008. >> http://clk.atdmt.com/MRT/go/vse0120000070mrt/direct/01/ >> _______________________________________________ >> Emc-users mailing list >> [email protected] >> https://lists.sourceforge.net/lists/listinfo/emc-users > > > ------------------------------------------------------------------------- > This SF.net email is sponsored by: Microsoft > Defy all challenges. Microsoft(R) Visual Studio 2008. > http://clk.atdmt.com/MRT/go/vse0120000070mrt/direct/01/ > _______________________________________________ > Emc-users mailing list > [email protected] > https://lists.sourceforge.net/lists/listinfo/emc-users > ------------------------------------------------------------------------- This SF.net email is sponsored by: Microsoft Defy all challenges. Microsoft(R) Visual Studio 2008. http://clk.atdmt.com/MRT/go/vse0120000070mrt/direct/01/ _______________________________________________ Emc-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/emc-users
