On Friday 11 December 2020 20:59:53 Jon Elson wrote: > On 12/11/2020 06:35 PM, Gene Heskett wrote: > > Greetings all; > > > > In playing some more with this servo, I am in the +-10% of right for > > the SCALE, getting that somewhere near right also lowered the Pgain > > from 300000 to around 2000, but demanded an FF1 of about 17.6. But > > after homing, which in this case is home at present location. I've > > found I have an offset, quite small at -0.004x degrees, but will not > > zero with a touch off to zero. > > That sounds like you are displaying ACTUAL position, not > COMMANDED position. > .004 degrees is pretty small, so maybe that is the range > where you have an effective deadband, and the PID won't move > it to the exact null position. You could try putting in > some I and see if it closes the gap. > > Jon
I'm not done fine tuning yet, I am more or less just learning how a servo works, here is what I have in the .ini file now: #******************** # Axis A #******************** [AXIS_A] MAX_VELOCITY = 1500.000 MAX_ACCELERATION = 2500.00 [JOINT_3] TYPE = ANGULAR HOME = 0.0 HOME_SEQUENCE = 3 HOME_SEARCH_VEL = 0 HOME_LATCH_VEL = 0 HOME_FINAL_VEL = 0 VOLATILE_HOME = 1 FERROR = 55550.050 MIN_FERROR = 55550.010 MAX_VELOCITY = 1500.000 MAX_ACCELERATION = 2500.00 P = 1900 I = 0 D = 1.5 FF0 = 0 FF1 = 17.6 FF2 = 0.275 BIAS = 0 DEADBAND = 0 MAX_OUTPUT = 0 SERVO_SCALE = 720 HOME_OFFSET = 0.0 PWMGEN_TYPE = 2 And it can march right along at 1500, still less than 40% pwm. It does hit reverse getting stopped, but not hard enough to kill the psu. The drag of the BS-1 will probably fix that. If the motor is getting 100% of its rated 24 volts, its rated speed is 220 rpms. If the BS-1 is 9 degrees per turn of the worm, that's 1920 degrees a minute. But the BS-1 is tight, trying to get zero backlash, so I'll be surprised if the motor can hit 100 rpm pulling the BS-1 while under good control, but even that is nearly 3 turns a minute. And beats the heck out of 4x the weight in iron in a stepper. Thanks Jon. 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) If we desire respect for the law, we must first make the law respectable. - Louis D. Brandeis Genes Web page <http://geneslinuxbox.net:6309/gene> _______________________________________________ Emc-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/emc-users
