tomp wrote: > howard > look at the numbers without the formula, just to get the relationships... > > i think... > you have 2.25 turn of motor to get 1 turn of screw ( 36/16 = 2.25) > > and 1 turn of motor makes 2000PPR which is 8000 counts ( due to quadrature)
I glossed over quadrature 1x vs 4x, and "counts per rev" vs "cycles per rev" vs "pulses per rev", because Howard's error is not a nice simple factor of four. This is something to keep in mind in general though - encoder specs can be ambiguous. > so for 1 turn of screw you have 18000 counts from motor > ( 8000 counts per motor turn * 2.25 motor turns) > and > 1 turn of screw is 0.250" (inches) > which is > 6.35mm (0.25 * 25.4 = 6.35 ) > > so, 6.35mm travel = 18000 count > so 6350 microns = 18000 counts > so 1um of travel = 18000/6350 = 2.8346457 counts > > thats a pretty ugly number There are no "ugly" numbers with EMC2. Scaling is done in floating point, so it doesn't matter if you have 1003.267 counts per mm, EMC will move the correct distance (within one or two counts, of course). > there are an infinite number of screw and gear and ppr combinations that > wont yield nice counts per micron > so it is possible that you cannot get it with the combination you have > assembled Doesn't matter at all. Regards, John Kasunich ------------------------------------------------------------------------- This SF.Net email is sponsored by the Moblin Your Move Developer's challenge Build the coolest Linux based applications with Moblin SDK & win great prizes Grand prize is a trip for two to an Open Source event anywhere in the world http://moblin-contest.org/redirect.php?banner_id=100&url=/ _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
