On 9/22/2016 12:21 PM, Sag ich Dir nich wrote: > so now i added a scale (which is maximum rpm) and i can command various > speeds > but still the motor vibrates. somehow it sounds like it ramps up and down a > bit > when commanding for example 2000rpm. Noise could probably be, i may change > the > output to another port (had some coordinate moves with various spindle speeds > and when one axis changed direction, the motor stopped for a few > milliseconds), > is there any pin i can use for pwm that has 5v output on its own?
The PRU generated PWM output is fairly low frequency. You may need to increase the PWM frequency (which will decrease the available resolution) or use one of the hardware PWM outputs. I don't think there is a HAL driver to talk directly to the BBB's hardware PWM channels, but for spindle speed a user-mode python script should work fine. There is nothing on the BBB that generates a 5V output (3.3V only), and no 5V buffered outputs on the CRAMPS boards (just the FET outputs). If there is an analog input to your motor control, you could craft a low-pass filter and the low-speed PWM wouldn't matter that much. > what do you mean by "pull-up"? A pull-up resistor to 5V. A resistor between the FET output and the power rail to pull the output high when the FET turns off. -- Charles Steinkuehler char...@steinkuehler.net -- website: http://www.machinekit.io blog: http://blog.machinekit.io github: https://github.com/machinekit --- You received this message because you are subscribed to the Google Groups "Machinekit" group. To unsubscribe from this group and stop receiving emails from it, send an email to machinekit+unsubscr...@googlegroups.com. Visit this group at https://groups.google.com/group/machinekit. For more options, visit https://groups.google.com/d/optout.
