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 > > Are you off by a factor of 4? Your encoder may be 2000 cycles/rev, wich will produce 8000 quadrature counts/rev. I'm not coming up with anything that works out near 1250. You might turn the motor one revolution exactly and see what the change is on the display, to see if the stated encoder count is wrong. Depending on how you are reading the encoder, there may be a hal pin that produces absolute encoder counts without scaling to linear units.
Also, you should crank the encoder backa and forth a few times and return to the same spot, and see if the position reading is repeatable. If the encoder signals are weak, you might be losing counts. Jon ------------------------------------------------------------------------- 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
