On Tue, 13 Oct 2009, Sebastian Kuzminsky wrote: > Date: Tue, 13 Oct 2009 21:05:15 -0600 > From: Sebastian Kuzminsky <[email protected]> > Reply-To: EMC developers <[email protected]> > To: EMC developers <[email protected]> > Subject: Re: [Emc-developers] hostmot2 stepping folowing error oddity > > Peter C. Wallace wrote: >> At the lowest (hardware) level, the stepgen will not run faster than >> 1/(StepLen+StepSpace) regardless of whats programmed in the velocity >> register. >> one level above that the HostMot2 driver will not use a velocity greater than >> xxxx.maxvel. If .xxxx.maxvel is set to 0 the driver will chose maxvel based >> on >> the StepLen and StepSpace settings (with some headroom I hope). > > The driver currently does not hold back any headroom when maxvel is 0, > it uses 1/(StepLen+StepSpace). > > I think of "maxvel=0" as "trust the trajectory planner". In this mode > it's up to the TP to not ask for more than the stepgen can give. > > If the source of the position-cmd is not a trustworthy trajectory > planner, maxvel can be specified by the human, and the driver will of > course honor it. (And the same for maxaccel.) > > Do you think it should be different?
No, I think its fine (probably already too many belts+suspenders), I was wondering if it might be related to the asymmetry that Chris noticed however. I'm not convinced that a direction change at start would make much difference since at the low initial velocities in the first few steps the stepgenerator should catch up since it has adequate velocity headroom at the start of the move (the FERROR is close to zero until the middle of the plot) > > > -- > Sebastian Kuzminsky > > ------------------------------------------------------------------------------ > Come build with us! The BlackBerry(R) Developer Conference in SF, CA > is the only developer event you need to attend this year. Jumpstart your > developing skills, take BlackBerry mobile applications to market and stay > ahead of the curve. Join us from November 9 - 12, 2009. Register now! > http://p.sf.net/sfu/devconference > _______________________________________________ > Emc-developers mailing list > [email protected] > https://lists.sourceforge.net/lists/listinfo/emc-developers > Peter Wallace Mesa Electronics (\__/) (='.'=) This is Bunny. Copy and paste bunny into your (")_(") signature to help him gain world domination. ------------------------------------------------------------------------------ Come build with us! The BlackBerry(R) Developer Conference in SF, CA is the only developer event you need to attend this year. Jumpstart your developing skills, take BlackBerry mobile applications to market and stay ahead of the curve. Join us from November 9 - 12, 2009. Register now! http://p.sf.net/sfu/devconference _______________________________________________ Emc-developers mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/emc-developers
