[buscht]

I've been running 116oz-in stepper motors with the Xylotex/TurboCNC setup.

My programs will be over 50,000 lines in length and I have been experiencing lost steps while running parts.

My thinking was that I needed to slow my feedrates down or get bigger motors. I slowed the feedrate down from 30" per minute to 20", but still lost steps.

I decided then to buy the largest stepper motors that I could find that met the Xylotex board requirements.

Here's what I bought. NEMA 34 mount, 680 oz-in holding torque, 18 oz-in detent, bipolar series, 2 Amps DC, 6.8 Volts DC, 1.8 degree step angle.

I set my Vref to 2.75 for the 2 Amps DC, hooked up the motor and applied power. 24volts. The motor locked up perfectly and I couldn't overcome the power of the motor by trying to twist the shaft.

My problem came when I tried to jog the motor. I figured that the power requirement specs for the motor were very similar to the 116oz-in motors so I did not change anything in TurboCNC and tried to jog the motor. All I got was a bunch of noise and no movement.

After much fiddling around, I found that I had to add a value of 400 to the pulsewidth (uS) in the motion setup to get the motor to turn consistently.

The motor spun smoothly and was very strong. I couldn't stop the motion of the shaft at all. The problem is that with that high of a pulsewidth, my motor is only turning at about 60RPM. For my ball screws with a pitch of .203, that equates to about 12 IPM. Not at all what I want.

If I lower the pulsewidth, say to 200. The motor will turn, but its very weak and I can stop the motion with my fingers.

By the way, the Xylotex board is step for 1/8 micostepping. Max Speed 15000, Accel 20000, Max start speed 5000. This should give me a top end of 112.50 IPM

I am stumped and any help is greatly appreciated.
Trent