2012/12/21 andy pugh <[email protected]>: > On 21 December 2012 08:42, Viesturs Lācis <[email protected]> wrote: > >> What I observed is that pid got saturated as the motor was 20-30 >> degrees from its commanded position. I guess that tuning is pretty >> tight. > > Actually, that doesn't sound particularly tight. I would expect to be > hitting full scale rather earlier than 30 degrees of shaft movement. >
Thanks! What is better in my case, when motors are bigger than drive would like them to be (I mean that they are drawing too much current)? Tight tuning or softer feedback loop? >> How can I make those lines smoother? I am trying to play with P, I and >> D, but I do not see any improvement. I can get the overall ferror >> bigger or smaller, but I would like to make the line itself smoother - > > D _ought_ to damp the movement. I would try increasing that, then try > some more P too. Ok, will try that. >> This motor moves the Z axis, which has plasma torch mounted >> on it, so the load should remain approximately as it already is there. > > It is possibly worth looking at what the steady-state duty-cycle is, > (ie what PID output is needed to support the weight of the head) then > put that value in the PID bias (or is it called offset). > That should allow the PID to operate more symmetrically. The crazy thing is that motor screws up everything again. And funny part is that upwards it moves nicely, but downwards it is slower, as if there was some resistance, and pid reaches max output limit. The same happened with Y motor as well - yesterday it was fine, today it is not. What I tried is cfg=h for it and then bldc.value = 0.6 instead of 0.15. And I can hear it vibrating. So I am now trying to change hall sensor alignment. The sound has changed, so there is something there... -- Viesturs If you can't fix it, you don't own it. http://www.ifixit.com/Manifesto ------------------------------------------------------------------------------ LogMeIn Rescue: Anywhere, Anytime Remote support for IT. Free Trial Remotely access PCs and mobile devices and provide instant support Improve your efficiency, and focus on delivering more value-add services Discover what IT Professionals Know. Rescue delivers http://p.sf.net/sfu/logmein_12329d2d _______________________________________________ Emc-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/emc-users
