On Wednesday 25 March 2015 20:22:14 andy pugh wrote: > On 26 March 2015 at 00:12, Gene Heskett <ghesk...@wdtv.com> wrote: > > I had to reduce the P in the pid to the point it was essentially > > worthless at sub 300 rev speeds. > > I am not sure that P is appropriate for a speed controller. > The point is that P = 0 when the speed is correct. But you don't want > 0 PID output when the speed is correct, or the speed will stop being > correct. > So, a speed loop might want to be mainly FF0 and I.
You AIR, said that when I was doing the setup, but the regulation was very poor. Let me go see what its actually using now. #******************** # Spindle #******************** [SPINDLE_9] P = 75.000 I = 1.000 D = 0.000 FF0 = 86.00 FF1 = 2.000 FF2 = 0.000 BIAS = 0.0000 FBIAS = 38 RBIAS = -38 ACCEL = 5.7 LIMIT3_ACCEL = 1600.0 LOWGEAR = 2.125 DEADBAND = 0.000 # diff between s_max_outut and s_scale sets max pwm duty, make max_out 98% of s_scale LIMIT3_S_MAX_OUTPUT = 2048 # But it needs clipped in both directions, so... LIMIT3_S_MIN_OUTPUT = -2048 ENCODER_SCALE = 200.0 PWMGEN_S_SCALE = 2100 PWMGEN_S_FREQ = 25000 # near_tol is now in %, 12.5 IOW NEAR_TOL = 0.5 NEAR_SCALE = 1.075 ENCODER_SAMPLE = 500000 And its running decently. The weight of the chuck makes a pretty good low pass filter. Cheers, Gene Heskett -- "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> ------------------------------------------------------------------------------ Dive into the World of Parallel Programming The Go Parallel Website, sponsored by Intel and developed in partnership with Slashdot Media, is your hub for all things parallel software development, from weekly thought leadership blogs to news, videos, case studies, tutorials and more. Take a look and join the conversation now. http://goparallel.sourceforge.net/ _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
