On Saturday 14 December 2013 11:38:26 Marius Alksnys did opine: > Thanks, I will try it. > This is something what I was thinking about and even tried to swap pid > and offset addf lines, but I never found importance of addf order in > documentation, which would be worth noting there..
It is important. In both threads. General rule of thumb in base thread, addf anything that needs a sample from hdwe (encoder?) addf in order, the chain of non-fp stuff the sample flows through addf last (for steppers) the parport.N functions General rule of thumb for servo thread speed stuff: addf signal receiver FP stuff (such as an encoder) addf the module its "net" output goes to addf next module the "net" of the above goes to addf continue till this function is completed That way any changes in the signal are propagated thru the processing chain in a single servo cycle. And when the actual control outputs are updated, they are working with the most up to date data they can get. There are times I expect when you may have another function chain that needs to be interleaved with the above, but I haven't run across a case where I could test and get a demonstratable advantage. YMMV of course. Spindle control servos, based on an encoders velocity, will get very unstable if the path is backwards thru the addf's because this severely restricts the bandwidth of the control. Even with what I THINK is all the ducks in a row, I found that double the speed of the servo thread from 1 millisecond to .5 milliseconds was a huge improvement. Because of non- linearity in the pwmgen and controller, I have a linear module between the PID.out and the PWMGEN.in, additional time delay, but it sure tames the PID.error range. Decent load torque at creep speeds (50 rpms) without hunting at 75% speeds (1200 on up) where its very sensitive. In retrospect, and I'd have to make additional room for it now, I know I would have been schmardter to have used the PMDX-106 (or whatever is being sold for that now) in place of the cheaper, too darned cheap and slow & needs modification to raise its control bandwidth if its anywhere in a feedback chain, CNC4PC C41 for that translation function. Dumb, but its done. I won't make that mistake again, it, out of the bag, is simply not suitable for use in a servo controlled environment. You have been warned... > On 2013.12.14 13:12, andy pugh wrote: > > On 14 December 2013 08:08, Marius Alksnys <marius.alks...@gmail.com> wrote: > >> I tried simple configuration (without offset component) too. And it > >> worked perfectly. > > > > If it goes wrong with the offset component but works without it, then > > I suspect that the problem is with the execution order of the motion > > controller and the offset component. > > If you change the sequence of the "addf" statements in the HAL then > > you can probably make it work. > > ------------------------------------------------------------------------ > ------ Rapidly troubleshoot problems before they affect your business. > Most IT organizations don't have a clear picture of how application > performance affects their revenue. With AppDynamics, you get 100% > visibility into your Java,.NET, & PHP application. Start your 15-day > FREE TRIAL of AppDynamics Pro! > http://pubads.g.doubleclick.net/gampad/clk?id=84349831&iu=/4140/ostg.cl > ktrk _______________________________________________ > Emc-users mailing list > Emc-users@lists.sourceforge.net > 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) Genes Web page <http://geneslinuxbox.net:6309/gene> Isn't it nice that people who prefer Los Angeles to San Francisco live there? -- Herb Caen A pen in the hand of this president is far more dangerous than 200 million guns in the hands of law-abiding citizens. ------------------------------------------------------------------------------ Rapidly troubleshoot problems before they affect your business. Most IT organizations don't have a clear picture of how application performance affects their revenue. With AppDynamics, you get 100% visibility into your Java,.NET, & PHP application. Start your 15-day FREE TRIAL of AppDynamics Pro! http://pubads.g.doubleclick.net/gampad/clk?id=84349831&iu=/4140/ostg.clktrk _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
