I agree with you entirely, thats why I put quadrature in the HAL step generator :-)
Linuxcnc has had quadrature output as an option since the first release of EMC2. The HAL software step generator actually makes about 15 different kinds of pulse sequences. (Many are only suitable for ultra-cheap and poor performance "drives" that directly switch the motor windings with the step signals.) The problem is that drive manufacturers tend to support the defacto standard, and that is step/dir, not quadrature. But if you have a drive that takes quadrature, LCNC can drive it. On Sun, Aug 10, 2014, at 02:23 PM, Philipp Burch wrote: > Hi andy! > > On 10.08.2014 20:17, andy pugh wrote: > > On 10 August 2014 18:49, Philipp Burch <p...@hb9etc.ch> wrote: > >> If you generate steps in software, that means that your maximum > >> step rate will be far below the thread frequency. > > > > This problem is worse with quadrature (which is otherwise, as you say, > > a rather better approach) > > > > LinuxCNC can make a step pulse every base thread, (using the "reset" > > function). It takes 4 base threads to make a quadrature cycle (though > > I guess every change in state can be interpreted as a step, so perhaps > > I am wrong about it being slower) > > Ok, I didn't take the reset function into consideration. It needs some > extra consideration to setup the dir line if needed to, but yes, that > makes it faster on the software side at least. So it would almost match > the quadrature performance, which should obviously count every edge, not > just every full cycle. The latter wouldn't be of much use in my opinion. > > Cheers, > Philipp > > ------------------------------------------------------------------------------ > _______________________________________________ > Emc-users mailing list > Emc-users@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/emc-users > Email had 1 attachment: > + signature.asc > 1k (application/pgp-signature) -- John Kasunich jmkasun...@fastmail.fm ------------------------------------------------------------------------------ _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
