On Thu, 22 Jun 2017 00:06:42 +0100 andy pugh <bodge...@gmail.com> wrote:
> On 21 June 2017 at 19:36, Peter C. Wallace <p...@mesanet.com> wrote: > > > The stepgen is not computing following error it just cant be driven by a > > position command with a stepwise discontinuity and move instantaneously to > > the new position. > > > I think it might be more interesting than that. Stepgen commanded position > and encoder position track each other very well, and the f-error is small > throughout. > > https://docs.google.com/spreadsheets/d/1qRVyQWFl4BIsSNKwy9IYsXrmZLTK8vgVVNX4tAuUmJM/edit?usp=sharing Yes there could be a following error for stepper generator. I think it is like this, it output step frequency and number of stepped steps backs so there could be a difference. I modified stepper driver for my own card and also discovered decimal point is useful then stepping with a frequency close to servo loop. Without decimal there will be quite a lot of jitter then switching between integer number of steps and decimal point place flanks withing period. It might be step speed have been chosen to avoid jitter. ------------------------------------------------------------------------------ Check out the vibrant tech community on one of the world's most engaging tech sites, Slashdot.org! http://sdm.link/slashdot _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users