Massive osccillations after switching from parallel to 6i25

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06 Jun 2021 18:52 #211318 by naja452
I just recently switched my machine from parallel to a 6i25 for more IO and now I have massive oscillations when I use the jog wheel and often during jobs that will cause a following error once it gets bad enough.

I'll attach video showing the issue, how I can reproduce it, and halscope of the oscillation. I've attached the hal and ini files as well.
I also attached a picture of a job that failed with an arc that looked more like a zig zag right before it failed.


photos.app.goo.gl/CL5CjZ1fxwWosksP6


Things I've tried/checked.
making sure the accel values have enough overhead (already done by pncconf is seems)
uncommenting the pid.0.maxerror 0.0005 lines in the hal file, which made the oscillation WAY less but not gone.
The error seems to be in software since the oscillation is visible on the DRO as well.

Ive spent hours on this so hopefully someone knows whats going on!! THANKS!

My machine:
Tandem Y gantry
Gecko G540 with open loop steppers
6i25 with 5i25_g540x2.bit bitfile flashed
Linuxcnc debian - 2.9.0-pre0-135-g71bbc3c
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06 Jun 2021 19:20 #211325 by PCW
Try setting the servo period to the normal 1ms and all P terms to 1000
The following user(s) said Thank You: naja452

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06 Jun 2021 19:55 - 06 Jun 2021 19:55 #211339 by naja452
Huh, is it supposed to be 1000us by default?
Mine is at 10ms then. I'll change it and try again.
Last edit: 06 Jun 2021 19:55 by naja452.

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06 Jun 2021 19:57 - 06 Jun 2021 19:57 #211340 by PCW
No, you had 100 usec, all times are in nanoseconds so 1 ms =
1000000 ns
Last edit: 06 Jun 2021 19:57 by PCW.

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06 Jun 2021 19:58 #211341 by tommylight
There are inputs on the second header wired and in use in hal, those wires have to be shielded and grounded properly, otherwise interference will cause such vibrations.

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06 Jun 2021 20:04 #211342 by naja452
I changed the servo period to 1000000 and now there's huge oscillations even when homing. WAY worse.

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06 Jun 2021 20:15 #211344 by naja452
Oh and the Ps to 1000 one sec.

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06 Jun 2021 20:18 #211345 by naja452
Wow, that's a million times better! Let me run my job again and see if it throws a following error again!

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