let's stand back a bit what we're really doing is forcing one component to accommodate the other, and vice versa, and both approaches have side effects; maybe the whole ferror thing is done in the wrong place to start with
what's ferror is actually about? AFAICT it serves really a single purpose, namely triggering a 'following error' condition if it gets too large. we have to sets of configurations, one with pid, one without. In the pid configs, we could use pid.error to trip a 'following error' condition. In the non-pid configs there's no such thing, but we still have motion commanded position and stepgen.N.position-fb. Now a different approach would be the following: - disable ferror and following error tripping altogether in motion (and then motion is too fat anyway, and it's not in the ten commandments it _has_ to be there) - for PID configs, use a (possibly separate) maximum detector for abs(pid.error) to trip - for stepper configs, use a (possibly separate) detector which trips on abs(commanded pos - stepgen.N.position-fb). actually the second mechanism could be used for both config types, all it needs is a rather simple detector component any glaring errors? -m Am 12.01.2013 um 21:12 schrieb Chris Radek: > On Sat, Jan 12, 2013 at 08:00:49PM +0000, andy pugh wrote: >> >> Doesn't this mean that there is no PID output for the first servo >> period after a setpoint change? > > Hmm yeah, it does seem like it will add a period's delay. > > Does pid need to keep track of both kinds of error? Report to > motion its success (previous command vs current feedback), but use > current command vs current feedback to calculate all the gains? > > I'm out of my depth here... > > ------------------------------------------------------------------------------ > Master Visual Studio, SharePoint, SQL, ASP.NET, C# 2012, HTML5, CSS, > MVC, Windows 8 Apps, JavaScript and much more. Keep your skills current > with LearnDevNow - 3,200 step-by-step video tutorials by Microsoft > MVPs and experts. SALE $99.99 this month only -- learn more at: > http://p.sf.net/sfu/learnmore_122912 > _______________________________________________ > Emc-developers mailing list > [email protected] > https://lists.sourceforge.net/lists/listinfo/emc-developers ------------------------------------------------------------------------------ Master Visual Studio, SharePoint, SQL, ASP.NET, C# 2012, HTML5, CSS, MVC, Windows 8 Apps, JavaScript and much more. Keep your skills current with LearnDevNow - 3,200 step-by-step video tutorials by Microsoft MVPs and experts. SALE $99.99 this month only -- learn more at: http://p.sf.net/sfu/learnmore_122912 _______________________________________________ Emc-developers mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/emc-developers
