On Friday, March 30, 2012 07:21:25 AM Viesturs Lācis did opine: > 2012/3/30 gene heskett <[email protected]>: > > One mistake in the above Viesturs, in your 40 kilohertz base_thread > > loop description, linuxcnc has been able to issue a complete step > > pulse per loop iteration for something like 3, maybe 4 years now. It > > does this by timing a 2 or 3 microsecond pulse out and clearing the > > output bit(s) that need to be cleared while in that particular > > instance, not by waiting to clear it in the next iteration of the > > base_thread. > > Thank You for correcting that! > Anyway, it does not contradict to my point that software step > generation is not as smooth as hardware, which was my main point > there. > > Viesturs > And it is a totally valid point. Hardware step generation allows the accell profiles to more closely match what the stepper can do when it is well into its higher speeds and the torque falloffs that go with insufficient time to reach full coil currents at those higher speeds. But by bringing those speeds into the usable envelope of the machine, much of that torque falloff can be offset by moving to higher supply voltages. It also tends to find the resonant frequencies easier, making dampers more important at the higher speeds.
> ------------------------------------------------------------------------ > ------ This SF email is sponsosred by: > Try Windows Azure free for 90 days Click Here > http://p.sf.net/sfu/sfd2d-msazure > _______________________________________________ > Emc-users mailing list > [email protected] > https://lists.sourceforge.net/lists/listinfo/emc-users Cheers, Gene -- "There are four boxes to be used in defense of liberty: soap, ballot, jury, and ammo. Please use in that order." -Ed Howdershelt (Author) My web page: <http://coyoteden.dyndns-free.com:85/gene> Your mind understands what you have been taught; your heart, what is true. ------------------------------------------------------------------------------ This SF email is sponsosred by: Try Windows Azure free for 90 days Click Here http://p.sf.net/sfu/sfd2d-msazure _______________________________________________ Emc-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/emc-users
