Sam, That little green machine of yours really hauls. What pitch screws and motors (belts/pulley ratio) are you using on the XYZ axis? John
> -----Original Message----- > From: Sam Sokolik [mailto:[email protected]] > Sent: March-04-21 9:59 AM > To: Enhanced Machine Controller (EMC) > Subject: Re: [Emc-users] Following Error Joint 2 > > 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 <[email protected]> > 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 > > [email protected] > > https://lists.sourceforge.net/lists/listinfo/emc-users > > > > _______________________________________________ > Emc-users mailing list > [email protected] > https://lists.sourceforge.net/lists/listinfo/emc-users _______________________________________________ Emc-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/emc-users
