On Wed, 2011-03-16 at 15:35 -0700, Kirk Wallace wrote: ... snip > The PWM frequency will be determined by the thread rate that the PWM > component is loaded in - usually the servo thread or 1kHz (?). The G540 > doc hints at 50Hz, but I think it will work anyway. This is off the top > of my head, so check the above for yourself. ... snip
Well it looks like I got the pwmgen stuff wrong. Use the documentation here: http://www.linuxcnc.org/docview/html/man/man9/pwmgen.9.html " pwmgen.N.pwm-freq float rw - PWM frequency in Hz. The upper limit is half of the frequency at which make-pulses is invoked, and values above that limit will be changed to the limit. If dither-pwm is false, the value will be changed to the nearest integer submultiple of the make-pulses frequency. A value of zero produces Pulse Density Modulation instead of Pulse Width Modulation. " " pwmgen.N.dither-pwm bit rw - Because software-generated PWM uses a fairly slow timebase (several to many microseconds), it has limited resolution. For example, if make-pulses is called at a 20KHz rate, and pwm-freq is 2KHz, there are only 10 possible duty cycles. If dither-pwm is false, the commanded duty cycle will be rounded to the nearest of those values. Assuming value remains constant, the same output will repeat every PWM cycle. If dither-pwm is true, the output duty cycle will be dithered between the two closest values, so that the long-term average is closer to the desired level. dither-pwm has no effect if pwm-freq is zero (PDM mode), since PDM is an inherently dithered process. " -- Kirk Wallace http://www.wallacecompany.com/machine_shop/ http://www.wallacecompany.com/E45/index.html California, USA ------------------------------------------------------------------------------ Colocation vs. Managed Hosting A question and answer guide to determining the best fit for your organization - today and in the future. http://p.sf.net/sfu/internap-sfd2d _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
