I think the problem with temp correction is where to put the thermometer, ptd, etc. Important components have widely differing thermal mass. Might be easier to liquid cool/heat the major pieces ... or the room/ enclosure. I think some of the big boys cool/heat.
Just my tuppence. Dave On Jan 21, 2008, at 1:02 PM, sam sokolik wrote: > 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)" <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 ------------------------------------------------------------------------- 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
