On Tuesday 26 May 2020 11:55:05 Jon Elson wrote: > On 05/25/2020 07:43 PM, Gene Heskett wrote: > > Without PID's, where do we get a following error that we > > can see on the halscope? > > OK, WITHOUT a PID, then the step generators have a maximum > speed, set by (possibly) > BASE_PERIOD, step_width and step_space. No BASE_PERIOD, servo thread only
STEPLEN & STEP_SPACE vary acc the driver but would be 3250 x 2 for the slowest. 6500 ns but longer at direction changes. Thats nominally 155 kilohertz for a max step rate, so in reality, motor inductance causeing a loss of torque and a stall will be the first effect actually seen. Somewhat mitigated by raising the applied voltage, within the limits imposed by the drivers power stage. Thats a per second value. But lets be safe and assume 100 kilohertz. plug in the microstep setting of the driver and get an inches per second if you punched all the right buttons. Thats a huge IF. > If you set maximum > velocity in the ini file > above that limit, you will get following errors. So, you > have to know from the setup > of the step generators what the max speed is, and then be > sure to not set max velocity above > that. You should have no need to scope it, but you could > probably get this on most systems > by looking at the commanded position and the actual > position, if the step generator provides > this. > The mesa cards provides a .pos-fb data line that I assume is how many steps, and should match the .pos-cmd value from the TP? That hookup is present in the .hal file. The MAX_VEL's are set at 50 to 75% of the stall speeds. Subject change: Those closed loop motors and controllers have arrived, and I puzzled by a total lack of docs other than the u-step ratios printed on the cover. Thats covered by dip sw1-4, but its a 6 pos switch, and 5 & 6 are in Chinese pictograms. It also has a 6 wire rj jack like a phone handset labeled rs232. The motor has about an 18" power cord, but the encoder is at least 2 meters. Obviously I'll have to extend the motor cable. And the motors are shorter than I assumed from the pix as I was comparing the driver to a 2m542, and its at least 25% smaller than a 2m542. It may even fit the X on the sheldon, maybe... thats a nema-24 motor in there now. Dual shaft, back shaft clears the bed about 1/4" now. Now to see if my google-foo can find me some docs on the care and feeding of a "LCDA367H" driver. There are also a pair of 220 ohm 1/8 watt R's in each box??? Manual was easy, but rs232 for tuning is not documented, claims it automatic. We'll see. I bought some 48 volt, 7.5 amp rated supplies I'll turn down to 42 volts as the driver is rated for 20-50. Ack the manpages, the resistors are for 24 volt step/dir sigs. Guinea Pig at work IOW. But I still don't grok why the encoder cable is 2 meters long, but the motors cable is half a meter, when the two plugs are cheek to jowl adjacent on the controller. Haven't had net or phone most of the day. I get em both from the local cable, shentel. But no cable tv. Stay well 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 Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
