On Feb 24, 2013, at 2:54 AM, emc-users-requ...@lists.sourceforge.net wrote: > From: Roland Jollivet <roland.jolli...@gmail.com> > Subject: [Emc-users] PPMC.ini, Help with my math > Date: February 24, 2013 1:38:49 AM PST > To: "Enhanced Machine Controller (EMC)" <emc-users@lists.sourceforge.net> > Reply-To: "Enhanced Machine Controller \(EMC\)" > <emc-users@lists.sourceforge.net> > > > On 24 February 2013 01:40, Bruce Klawiter <bmkl...@yahoo.com> wrote: > >> I have just switch my mill over from linear scales to rotary encoders and >> I can't get my input scale right. OUTPUT_SCALE is 1, Units-inch >> > > X axis has a 1250 CPR differential encoder, motor 14 tooth gear, screw 21 >> tooth gear, .200 pitch screw. 1250 X 4 X 1.5 X 5 = INPUT_SCALE = 37500 >> > > My arithmetic may be way off, but I don't understand any of the above. > Where does 1.5 and 4 and 5 come into it? > > The way I see it, 1250 counts = 1 motor rev = 14/21 x 0.2 = 0.13333333 in > > therefore, 1 count = 0.133333 /1250 = 0.000106666 in > or, 1 inch = 9375 counts. > > You should in any case, be able to jog the motor for 10 inches linear > travel and get a ballpark figure. Then /10 and you'll know 95% of what > you're aiming for. > > Roland Roland,
I think that the 4 comes from the fact that and A-B encoder counts rising and falling edges of each channel thus a 1250 count encoder results in 5000 counts per rotations (1250 * 4). The 5 is a .200 pitch screw rotates 5 times per inch. The 1.5 is because a 14 tooth gear on the motor must turn 1.5 times to cause a 21 tooth gear on the screw to turn 1 time. Alan ------------------------------------------------------------------------------ Everyone hates slow websites. So do we. Make your web apps faster with AppDynamics Download AppDynamics Lite for free today: http://p.sf.net/sfu/appdyn_d2d_feb _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
