On Wednesday 24 June 2020 14:48:09 andrew beck wrote: > All it says is they use pwm for controlling via x72 x80 x82 etc. > > I forgot to what most buy as you say it doesn't matter really. > > I am more interested in how pwm works. > > As far as I know there is a voltage and duty cycle and a dir. But I > haven't used it before.
Three wires, two signals, against ground or logic zero. Its common if driving a motor driver, to use the 5 volt line as the common, and logic zero is the on state because the transistors in the average breakout board can pull low much better than the can push high. The diff can be 10/1. One is direction, commonly a logic zero means backwards The other signal can be of any time duration but should be fast enough so as an averaging circuit won't have too much ripple in it. The percentage of that time it spends at a logic one, from 1% to 99% represents the requested speed, if it spends 25% of its time at a logic one, that represents a request for 25% of full speed. Etc, etc. In practice, the repetition rate is often several kilohertz, the higher it is, the faster the motor will try to respond, but if being transmitted thru an opto isolator, will often be time distorted by the lags of the opto stuff destroying the linearity of response, sometimes very obviously. This will often force a lower than optimum carrier frequency. In some cases, the lower limit has been extended by skipping pulses such that the lowest speed is around 30 rpm for a 3000 rpm max spindle. > Regards > > Andrew > > On Thu, Jun 25, 2020, 12:51 AM andy pugh <[email protected]> wrote: > > On Wed, 24 Jun 2020 at 13:45, andy pugh <[email protected]> wrote: > > > On Wed, 24 Jun 2020 at 12:30, andrew beck > > > <[email protected]> > > > > wrote: > > > > as some of you will know I am trying to connect to a heidenhain > > > > inverter > > > > > > unit on my cnc mill > > > > > > Which model? > > > > (Not that it matters, there seems to be no useful info in that > > document) > > > > -- > > atp > > "A motorcycle is a bicycle with a pandemonium attachment and is > > designed for the especial use of mechanical geniuses, daredevils and > > lunatics." > > — George Fitch, Atlanta Constitution Newspaper, 1912 > > > > > > _______________________________________________ > > Emc-users mailing list > > [email protected] > > https://lists.sourceforge.net/lists/listinfo/emc-users > > _______________________________________________ > Emc-users mailing list > [email protected] > https://lists.sourceforge.net/lists/listinfo/emc-users Cheers, Gene Heskett -- "There are four boxes to be used in defense of liberty: soap, ballot, jury, and ammo. Please use in that order." -Ed Howdershelt (Author) If we desire respect for the law, we must first make the law respectable. - Louis D. Brandeis Genes Web page <http://geneslinuxbox.net:6309/gene> _______________________________________________ Emc-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/emc-users
