It sounds like you get gravel in the servo motors from time to time.
Or you get click sounds from the motors. It repeats itself with a few or many minutes apart.
The first thing to do is to enable syncToRefClock and enable DC mode for the servos,
this will keep the servo loop in sync with the DC.
What grandixximo is doing here is fixing an effect that despite DC and servo loop are synchronized,
the two loops have been started with an undetermined/unfortunate phase between them.
The gravel sound is there all the time and it doesn't go away until linuxcnc is restarted.
Surprisingly, yesterday Sasha Ittner popped up in the PR log and mentioned he had been working
on a complete redesign of the DC system, eliminating all these problems (don't know details)
grandixximo seems to have reviewed that work and decided to adopt Sasha's work.
grandixximo will have to say himself. And if you don't know, Sasha Ittner is the author of linuxcnc-ethercat
from many (>10) years ago.
After reviewing on real hardware today, I found my original PR works better than what Sascha Ittner did in his repo, I reverted back to the original state before I started reviewing Sasha's work.
If anyone wants to help me test, I'd love feedback on the code in my repo, because for me this is what works.
github.com/grandixximo/linuxcnc-ethercat
But I need more data from other testers.
To prove the system works, you should get grinding noise, if you set sync0shift of your drive to be half your max servo latency, open halscope and scope your servo-thread and open a couple of glxgears to induce latency in the servo thread, this should induce the grinding noise, and the noise will not be anywhere else.
