Ytai, Regarding your point #2. The stepper motor is rated for 1.2A so I set the current limit on the DRV8834 <http://www.pololu.com/file/0J617/drv8834.pdf> drive to 1.2A by setting the reference voltage to 0.59V* (Current Limit = VREF × 2*)
Should I increase the reference voltage to a higher value so the torque is increased? Can you please explain a little bit what you meant with #1 and #4 (Reduce the load and slow down)? Are you suggesting to use 1/16 or even 1/32 microstep resolution instead 1/8? Thanks, and best regards! On Saturday, October 11, 2014 9:55:37 PM UTC-7, Ytai wrote: > > The stepper is missing steps when its cannot accelerate fast enough to > keep up with the electric commutation. You can mitigate this by: > > 1. Reduce the load on the motor. > 2. Increase torque ~= current, if your motor and driver are capable of > it. > 3. Rate-limit the speed change (i.e. limit acceleration). > 4. Slow down. > > > On Sat, Oct 11, 2014 at 8:25 PM, Al B <[email protected] <javascript:>> > wrote: > >> When I try to setup the period with a value under 40, then the stepper >> <http://www.pololu.com/product/1200> motors stop moving and start >> vibrating like they are missing steps. By looking at the ShoeBot app, it >> seems that Ytai is able to set the period as low as 15. I using 2 of these >> DRV8834 <http://www.pololu.com/file/0J617/drv8834.pdf> Low-Voltage >> Stepper Motor Drivers with a 1/8 microstep resolution; which are a little >> bit different to the A4988 >> <http://www.pololu.com/file/0J450/a4988_DMOS_microstepping_driver_with_translator.pdf> >> >> drivers used on the ShowBot. However, I don't think they are imposing this >> limitation. My app also uses a CLK_62K5 clock and the loop() method >> updates the period every 2ms. >> >> Any suggestion or comment will be appreciated. >> >> Thanks! >> >> -- >> You received this message because you are subscribed to the Google Groups >> "ioio-users" group. >> To unsubscribe from this group and stop receiving emails from it, send an >> email to [email protected] <javascript:>. >> To post to this group, send email to [email protected] >> <javascript:>. >> Visit this group at http://groups.google.com/group/ioio-users. >> For more options, visit https://groups.google.com/d/optout. >> > > -- You received this message because you are subscribed to the Google Groups "ioio-users" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To post to this group, send email to [email protected]. Visit this group at http://groups.google.com/group/ioio-users. For more options, visit https://groups.google.com/d/optout.
