Howard Howard Chan wrote: > Dear all, > At first, I used latency-test to check my computer and I set the > BASE_PERIOD to 25000. I used Integrator manual to calculate the > INPUT_SCALE but it is not correct. > My machine requirements: > Unit using mm. > I hope the max rpm of motor is 1200. > I use SANYO DENKI servo motor which has an 2000 ppr internal encoder and > max rpm is 3000. The motor mounts a 16T pulley and connects a 36T pulley. > http://myweb.polyu.edu.hk/~icwfchan/p2.png > 36T pulley mounts a lead screw which is 4 turns per inch > http://myweb.polyu.edu.hk/~icwfchan/p3.jpg > > According to Integrator manual, my calculation is: > INPUT_SCALE=2000 * (36/16) * (4 /25.4)=709 > but the computer displays x-axis value is not the real-distance value. > I try and error to find the value round 1250 > > Would you mind telling me which part is wrong? > Thank you > > Howard > > > > ------------------------------------------------------------------------- > 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 > >
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) 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 but the sanyo denkii driver likely has 'electronic gearing' which is just a multiplier and a divider the incoming counts from the encoder is multiplied by the numerator and divided by the denominator and the output counts are reported to the control and 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 i'm actually in hk now, but just a visa run, try a spreadsheet to look at how numbers change i was able to get close to 1000 ounts per mmm, but never exact regards tomp ------------------------------------------------------------------------- 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
