On 01/01/2014 02:14 PM, Ed wrote: > > Encoders are on the end of the screw, 2-1 belt drive from motor, 1000 > line/4000 count > Assuming 5 TPI screws, that is 4000 * 5 = 20,000 counts/inch. One comment is with the encoders on the screw, the timing belt needs to be set very tight, so that the motor shaft and the leadscrew follow with minimal divergence. > I have tried both with and w/o Vel Est with little or no > difference. The board is a Ver 3.1 At 16 IPM it jogs fine > then faults when stopping. Keyboard input for all > functions. All axis have the tendency to have a lot of > resistance to influence the screw in one direction and > much less in the other, Y axis is the worst, Z axis is the > best > I did not notice a difference with the higher current limit. Hmm, this is very strange. The only thing that should have an asymmetry is the current limit. I think you need to run the Halscope and observe the output of the PID routine, the velocity and the following error to see what the problem is. You can post the graphs or email them to me if you can't interpret them. Also, see <http://wiki.linuxcnc.org/cgi-bin/wiki.pl?PWM_Servo_Amplifiers> for some info on tuning. I don't understand this asymmetric thing. You might want to check your wiring for any difference from the sample schematic. Also, what are you using for a 12 V power supply for the UPC and servo amps? >> You might want to step back and >> test your motors for performance. > They ran fine (72 IPM)when hooked to 320 gecko's at half the voltage. OK, that's a good data point. > 290 000 Ohms for 10 Amps That sounds reasonable. Are you using configs files derived from the univpwm sample config? What has been changed from the sample file?
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