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I think I got to the bottom of it. There were some locations I could twist the spindle (and hence spindle encoder) to manually that resulted in continued increases or decrease of the spindle position. This told me it was still noise so I dug into it.

I have no idea why, but on the mesa 7i76 the encoder input can be differential or single ended. I was using it in differential mode because I thought it would be more noise immune. I also had a "backpack" sort of thing on my encoder that made the single-ended outputs 3.3V differential. In this mode it uses a Renesas ISL32173 chip to take in the differential signal through what amounts to a comparator and output a logical signal to some counter in the FPGA. The issue is that the chip is designed to be really sensitive and a differential signal over 0.2V is considered high. That is nuts on a signal that is 3.3V or 5V differential. Hence, despite all my work it was still noise, but I decided to just go back to 5V single-ended at 5V directly out of the encoder and now all is well... despite the noise levels being higher in absolute terms the signal to noise ratio is much much better and I can cut perfect threads! (Yeah I had my scope on it a lot throughout this.)

I don't know why there is no warning in the datasheet about this. 200 mV of noise on a 3.3V-5V signal should NOT be causing this kind of issue. Typical levels of a high bit on 3v3 logic is >2V. I think for some reason they used an RS-422 chip and it was not the right choice in my opinion... especially without a giant flashing warning.

Maybe I'll mention this to Peter at mesanet. They make a great product... but I think this was a bit of an oversight.

OK i flipped the driver and extended motor wires to 4 feet away. It is not better, in fact is seems a bit worst and stops even quicker

1024 count encoder or 4096 encoder ? if it's a 4096 encoder, that's likely having resolution issues,. i ran into a similar issue with my lathe at 1000rpm, i wound up stepping down from a 4096 to a 1024 encoder. also check the max speed rating of the encoder, make sure it can handle the speed

Flip the drive upside down and move the motor as far from it as you can, test again.

I've tested both drivers separately and same issues. I've attached a picture and also a schematic, since I only had yellow wire lol...My grounds seem good, and the pairs from the motor are correct (unless it matters which pair go to direction and which to pulse?) 

drive.google.com/drive/folders/1hJbKoC8d...PaQxFqQY?usp=sharing  

I attached all files in google drive since they are too big; .hal, .ini, and the lspci info if that is helpful. Also in .ini the ferror values are at 10 but I have tried many different ranges of values.

I appreciate your time and help with this.
 

Now listed on e-Bay

7i77: www.ebay.com/itm/187437904485
7i92: www.ebay.com/itm/187437910243
7i73: www.ebay.com/itm/187437913918

(7177 Sold)

No. I didn’t. 

And here is a diff, what could be modified from left to right
 

I connected two TMC5160 drivers and a NEMA17 motor (from another driver) to the 24V power supply. The video shows the current with the motor running, and the second part of the video shows the motor holding current when stopped.
Each of the TMC5160 drivers drives a motor at 3A.

Line 20 has M0, but normally the next line is the problem, the first G1 move in the routine. Is spindle.0.at-speed true?

If it does not count reliably, it suggests a problem with
the quadrature.

The count should be absolutely consistent.

Tommylights suggestion to use an oscilloscope is good.

Also if you can run the spindle at (very) low constant speed you can look
at the encoder A/B signals with halscope.

The signals to watch are:

hm2_7i92.0.encoder.00.input-a
hm2_7i92.0.encoder.00.input-b
hm2_7i92.0.encoder.00.input-index

( assuming the spindle encoder is encoder 00 )

I wrote this parametric G-code program and it seems to run fine on my simulation machine.  But when I try to run it on the real machine it stops at line 20  and gives (Does not exicute line 20) no feedback as to why.  However my simulation machine is running Linuxcnc 2.9, and the real  machine is only on 2.7. 

When I press button Touch Off, i see menu. When I enter my value, can`t press OK

linuxcnc 2.10 Axis Lathe configuration 

See:
forum.linuxcnc.org/show-your-stuff/55248...-table-rotary#320834

Hi everybody,
i found some threats (e.g. Simulate a mesa 7i96 (solved)) where a component was written for mocking a 7i96e mesacard. Nevertheless i didn't found this component code published and as i'm using myself a 7i76e card i wrote a component on my own for mocking/simulating this driver.
My idea was to use the same .ini and .hal-files (and .tcl-files with some if statements -)) as on my real milling machine to keep the adaptions between simulation and real machine as low as possible.
In case it is interesting/helpful, i put the component-code on github.com/pkl42/linuxcnc_components_sim.git 
Also not all available pins are included right now, i added a detailed list on the git repository.
I tried to write the component in a generic way, so it should be quite easy to add missing pins or even adapting a 7i95 or 7i96 card.