On 04/01/2014 02:57 PM, Gregg Eshelman wrote: > On 4/1/2014 7:01 AM, John Kasunich wrote: >> On Tue, Apr 1, 2014, at 09:52 AM, Dave Cole wrote: >>> Actually 127 Pulse/rev works ok. >>> >>> If you have 5 TPI screws it works out to: 0.2 / 127 = 0.00157" per >>> pulse. If you count all of the edges of the full quad signal (which is >>> normal) you can divide that by 4 which is approximately .00157/4 = >>> .000393 in/count. >>> >> 127 is an odd encoder count, but I understand why: >> 0.000393" is 0.01mm. > So as it is I can get 0.01mm precision on the Z axis with its 5 TPI > ballscrew? > > You get .01mm RESOLUTION, but the servos need to have some deflection from the commanded position, which requires some jitter and deflection. Depending on how great your servo amps are, the following error may be kept to just a couple encoder counts, or it could be quite a bit more.
Jon ------------------------------------------------------------------------------ _______________________________________________ Emc-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/emc-users
