at end of rapid move axis following error ocurrs

This posting is a fork from my earlier post about how to "reread config files without restarting linuxcnc".

In answer to PCW question


This is from the issue I mentioned on another posting.
When I G0 at 60ipm in X axis for 5 inches the Xaxis errors out with a following error.
I am not sure what Y does since I haven't tested it yet.

Linux tri 3.10.0-862.14.4.el7.x86_64 #1 SMP Wed Sep 26 15:12:11 UTC 2018 x86_64 x86_64 x86_64 GNU/Linux
Ga-J1900n mobo
3-axis mill (bridgeport clone) s.e.m servo motors. Using inches.

Just loaded a fresh install of Wheezy and 2.8 from master.

The following error happens as the motion is coming to an end, within the last .3

current hal and ini files below

Thanks
Jim

My guess would be that the tuning is really wrong (especially FF1)

If you have velocity mode drives, these are good basic instructions for tuning:

gnipsel.com/linuxcnc/tuning/servo.html

Newer versions of pncconf have a bug where they dont connect the commanded velocity pins correctly, so its best to delete or comment out these lines:

net x-vel-cmd => pid.x.command-deriv
net y-vel-cmd => pid.y.command-deriv
net z-vel-cmd => pid.z.command-deriv

otherwise the FF1 term does nothing

PCW

If you have velocity mode drives. Do I have velocity mode drives?

Background:
Mill is a 1985 Alliant knee mill (bridgeport clone),
SEM servo motors w/tacho, westamp boards, anilam A-10
glass scales. Mesa 5i25-7i77
GA-J1900n mobo, Wheezy, realtime-3.4-9-rtai-686-pae,
Linuxcnc from github master.
Axis 2.8.0-pre1.4032-g7626740


Previously with Linuxcnc 2.7 and Debian 9.2 w/ 2.8 this error wasn't seen.

Thanks
Jim

If the drives have taco feedback they are velocity mode.

I get taco feedback sometimes...

Did you delete the lines I mentioned?

This pncconf bug is a long standing issue but it did not show up until a PID bug that masked the pncconf bug was fixed recently

PCW

"Did you delete the lines I mentioned?"

Well I urrrr..
I had commented them out but now there is a question if Linuxcnc was restarted before running the positioning test.

Because I went back and deleted the lines and ran the positioning test and everything works correctly. Now no error where it was appearing in the program before.

Thank you again
Jim