2012/1/27 Peter C. Wallace <p...@mesanet.com>: > > This is not likely a tuning problem...
Sounds encouraging :) > More likely that you have either run out of headroom (what is the motor > voltage vs supply voltage?) or you have a commutation problem. Commutation > problems will happen if you have encoder count errors in q, qi, or qh mode > Of course if you have encoder count problems these need to be fixed whatever > commutation mode you use, but using h mode will eliminate encoder count > problems as a suspect in you oscillation troubles. > > Another detail that can cause strange behavior if you are close to the maximum > RPM because of voltage limits, is the maximum PWM duty cycle. This should be > limited via the PID components max_output parameter to about 95% of the PWM > components full scale value. Damn, thanks for reminding about the voltages! I have ~28 VDC supplied to 7i39s - that would account for supply voltage. Motors are rated for 36 VDC. Since motors are rated at 4000 RPM, I cannot reach them by default. But I still should hit 75% of that, which is 3000 RPM, because I have supplied 75% of the rated voltage, right? But now I have reached only half of that. Ok, is there a place I can read more about the max_output? I do not fully understand, what should I do with output_ scale and max_output parameters in INI file. Viesturs ------------------------------------------------------------------------------ Try before you buy = See our experts in action! The most comprehensive online learning library for Microsoft developers is just $99.99! Visual Studio, SharePoint, SQL - plus HTML5, CSS3, MVC3, Metro Style Apps, more. Free future releases when you subscribe now! http://p.sf.net/sfu/learndevnow-dev2 _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
