Problem with V2.6 upgrade and rotation axis not limiting to +-180 degree

[andrew...@gmail.com]

Was not having this problem with v2.4

The problem does not occur if I limit placements to one nozzle.

If I run a job with two nozzles being used some parts get put down at wrong rotation and the silicone tube get knotted up.

I looked at the logs and I get RED lines that say

"2026-03-19 21:12:58.553 AbstractMotionPlanner$SubordinateMotion WARNING: Subordinate Motion queue not empty: (C1:88.276618), drained."

I have the C1 and C2 axis set to limit 180 degrees.

What am I doing wrong?

[Mike Menci]

You need to use Vaccum rotating coupling at top of steeper motor shaft connecting to vacuum tube 

Dne 19. mar. 2026 ob 11:38 je oseba andrew...@gmail.com <andrew...@gmail.com> zapisala:



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<knotted_tube.jpg>

[andrew...@gmail.com]

I did buy some of those couplings but never used them because they didn't work great.  So instead I just used very flexible silicone hose.

The machine has run for many many years using the silicone hose without this problem.

OpenPNP version 2.4 did not have this problem.  If the nozzle was at 170 degrees and has to go too 190/-170 it would go the long way around.

I actually don't understand how it keeps twisting around as the Duet3D config sets the max rotation at +-190

BUT even if I did have a rotary coupling - It would not fix the wrong angle part placements that happen long before the hose gets twisted.

For example - I have a board that has two SOT23-6 USB-ESD-Arrays.

If I mark all small components (0603) on the board as disabled then these SOT23-6 both get placed correctly with the right-side nozzle.

If I allow the machine to run with both nozzles (placing 0603 Rs at the same time) the second SOT23-6 always gets placed 180 degrees wrong.  Not some random angle like missed steps/slipping-part would make.  Perfectly bottom-vision-aligned-and-180-degree-wrong

[Mike Menci]

Than you don’t have step/ mm - rotation set up right - remove the hose and test 360 deg - 1 turn 

Poslano iz iPhon-a

Dne 19. mar. 2026 ob 13:25 je oseba andrew...@gmail.com <andrew...@gmail.com> zapisala:



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