sorry to throw something else into the mix... I was getting following errors without realtime errors on the pie because the default internet time sync (timesyncd) sucked..
timesyncd vs ntp https://www.youtube.com/watch?v=RDKaFJmB254 On Thu, Mar 4, 2021 at 11:37 AM John Dammeyer <jo...@autoartisans.com> wrote: > > A following error is _expected_ if the stepgen maxaccel parameter is not > at > > least 2x the joints maxaccel value (or if any stepgen constraint is lower > > than what linuxCNC may command it to do) So HAL setup can absolutely > cause > > following errors. > > > > > > But if electrical noise from the higher load did cause a damaged UDP > packet > > > then there's the answer. A quick change in direction to handle > backlash and a > > > missing message throws out the timing and results in a following > error. John > > > > You can check this by plotting hm2_7i92.packet-error , but if setting the > > stepgen maxaccel value stops the following errors it does not seem > likely they > > are caused by lost packets. Plotting the following error will also give > you some > > insight into whats going on. > > > Hi Peter, > > One other thing about this. From > http://linuxcnc.org/docs/2.7/html/man/man9/hm2_eth.9.html#PACKET%20LOSS > > "On the other hand, pid-stepper systems will run properly for extended > periods of time with packet loss on the order of .01%, as long as following > error is increased enough that having stale position feedback does not > trigger a following error. Altering the HAL configuration so that during > transient packet loss the pid and motion feedback value is equal to the > command value, instead of the stale feedback value, appears to improve > tuning. This can be accomplished with a mux2(9) component for each feedback > signal, using packet−error as the mux2 sel input." > > I have no idea from that paragraph how to program that into the HAL file. > An example would be handy. Which feedback signal? What does the mux > output do? > > From the same section: > "When a lost packet is detected, the packet−error pin is asserted in that > cycle, the packet−error−level pin is increased, and if it reaches a > threshold then a permanent low-level I/O error is signaled." > > I'm going to guess that low-level I/O error is a general > _Following_Error_Joint_2_? > > Going through the files at > > https://github.com/LinuxCNC/linuxcnc/tree/master/src/hal/drivers/mesa-hostmot2 > I can find "packet_error_limit" but nothing that reports the following > error. Still missing something. > > John > > > > _______________________________________________ > 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
