> 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
