copy-paste from terminal: uname -a Linux linuxcnc 4.19.71-rt24-v7l+ #1 SMP PREEMPT RT Fri Jan 1 21:15:16 GMT 2021 armv7l GNU/Linux As I said, this is the sd card image straight from the LinuxCNC website. I wanted to ask, is that the best route to go? I’m not terribly impressed with the latency numbers, though they appear to work when I don’t run anything else (i.e. LinuxCNC doesn’t abort). I plan to get this machine into service (operated by others) as soon as possible.
Here is a short video that illustrates the problem. https://youtu.be/DdYYpdC51Vs I did try with P=0, as suggested by Sam, and it was also a big improvement over the default configuration. It may have had a bit more of an aggressive whine, but stable, to my ears. When I have more time, I could use my scope to run an fft on the step signal to get data that is better than “sounds like bad bearings”. Configs are attached. They are mostly straight from the pncconf wizard, with the z axis removed. I may have fat-fingered the servo period in this copy, just so you know. On Wed, Feb 2, 2022 at 4:32 AM Sam Sokolik <samco...@gmail.com> wrote: > Could you post your configs? Could your hal functions be out of order? I > run pid steppers with RPI and don't notice this. > > Sam > > On Wed, Feb 2, 2022, 3:01 AM andy pugh <bodge...@gmail.com> wrote: > > > On Wed, 2 Feb 2022 at 07:44, Thaddeus Waldner <thadw...@gmail.com> wrote: > > > > > 2) why is servo thread jitter even making into the stepper pulse train > > with a Mesa Ethernet card and no communication errors? Do I have anything > > misconfigured? > > > > The idea of using a PID is that it compensates for the fact that the > > servo thread updates don't get to the card exactly every servo period. > > Sometimes the feedback - calculate - send of the required step rate > > will run early, sometimes late. > > > > I am hoping that PCW might pop up to explain exactly why the PID helps > > here. It's not something I have paid that much attention to as I > > rarely use steppers. > > > > It might be interesting to try a non-pid config. (or just set P to > > zero which has about the same effect) > > > > -- > > atp > > "A motorcycle is a bicycle with a pandemonium attachment and is > > designed for the especial use of mechanical geniuses, daredevils and > > lunatics." > > — George Fitch, Atlanta Constitution Newspaper, 1912 > > > > > > _______________________________________________ > > Emc-users mailing list > > Emc-users@lists.sourceforge.net > > https://lists.sourceforge.net/lists/listinfo/emc-users > > > > _______________________________________________ > Emc-users mailing list > Emc-users@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/emc-users _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
