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Without a differential probe it's pretty hard so see,
but position recovery really seems like a drive or mechanical stall issue.

Can you set the drive following error limits tighter?

If it's possibly a drive strength issue, you could try single ended wiring.
(Since the drives have optoccoupler inputs this should have little effect on noise immunity)

 

In addition to the two polarities that need to be right
(TX to REQ and RX to data) The DPLL needs to be setup to
start the transfer _before_ LinuxCNC reads the data

I'll try and dig up a sample FANUC hal file Monday
 

It's fixed for all now

Some debugging. Per update above, mechanically things seem fine- I can shove the Y axis around and it's definitely not moving as much as the undercuts previously mentioned. I measured those, and the deepest is maybe ~0.01"/10 mil/0.25mm. Not as bad as I thought, still entirely unacceptable.

See attached pictures for some scope traces of one of the Y axis quadrature phases. Note that the measurement setup wasn't great for this, so there might be more noise represented here than is present in normal use- scope leads were dangling from jumper wires wedged into the cable ends, so... yeah.

With nothing moving, the signal idles at 5V +/- ~1.2V. Moving the X axis doesn't seem to influence this at all. Enabling the spindle adds some noise, dropping the signal as low as 2.3V. That's quite possibly enough to create false motion- minimum input to the servo is listed at 4V, but it also says it has digital filtering against noise, so... who knows. I should look at both A and B phases at once, but ran out of time. The fourth picture shows the Y axis moving- it's pseudo-differential, which in this case I don't think is actually buying anything, since the motor inputs are opto-isolated.

All of the above seems suboptimal, but I'm not seeing how it would somehow create extra steps in -Y, then somehow seemingly exactly recover them when going to +Y. Unless I want to level-shift, I'm not aware of a way to get the 7i76E to output > 5V on the motor control pins.

Anything else I should check? I'll plan on getting traces of both A and B phases simultaneously. Is a 3D model of  the issue still helpful, or is the cross-section sketch sufficient?

I have created a basic .hal and declared the Fanuc channel, see attached .hal.

I am getting an error on startup of linux cnc:
 

When I watch the corresponding hal pins and turn the encoder I am not seeing any activity.

Any tips on what to check or adjust next will be greatly appreciated.

Screenshots before and after?

Hi All,
  I have been reading this forum for weeks now, and have managed to solve most of my problems without needing to ask a stupid question, But the time has come. Be gentle, this is my first post.   I will attach my files to this to help.
Current Setup:
Dedicated computer running Linux Mint Debian Edition 6 "FAYE"
LinuxCNC 3.4.1
Gmoccapy gui
3040 Chinese CNC controller.
XYZ motion, although it also had the forth Axis, I am not including that in my setup.
7i76E motion controller card
0-10V AVI
24000 RPM
800W water cooled Chinese spindle.

My files have been created with the PNCCONFIG wizard.
I have now reached a point where every time I run the wizard, it breaks something, and I have to roll back changes.
(Even when I change NOTHING, just click through the wizard, it still breaks my setup, and will not start.)

I have been carefully trying to edit my files manually, baby steps, and backups!


PROBLEM:
I am having trouble getting the spindle to correctly work in the Gmoccapy display.
I can turn on the spindle, and turn off the spindle
I have the spindle start at 5000 RPM, and this works.
The bar graph on the bottom shows  "5000                  0                  24000"
It starts at 5000, as that is my (min) setting, and the "0" in the middle would display a percentage if I could only increase it.
I cannot adjust the speed of the spindle in the Gmoccapy GUI as there are no speed controls.

I want to add speed controls. and I have tried to understand what is written here in this post,
but I just cannot get my head around what I am doing wrong.

May I ask a member here to please look over my files? Perhaps it is something easy?

Thanks in advance!
Swanie