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Occasionally, when using 'run' on the 'Test/Tune Axis' panel, for a back and forth test of 2", the movement at the end of travel oscillates around the endpoints. It isn't consistent, it will oscillate for a little bit and then stop oscillating and then start up again. I will try and post a video of this shortly. Any insight would be greatly appreciated!

This typically means that the P term is set too high in the local PID control loop.
For local control loops, P should be set to 1/(servo period in seconds), That is,
1000 for a 1 ms servo thread period or 500 for a 2 ms servo thread period.

The physical meaning of this P term setting is that any detected position errors
are corrected by the next servo thread invocation.

@ccatlett1984
Do not change the subject tittle as it makes it impossible to find when searching.
Thank you.

On the latest Linuxcnc images SPI should be enabled by default, this was an issue I had with the previous releases.
You specify which spidev mesaflash uses on the command line switch as the --addr, spix can be forced to use a particular SPI interface. The Linuxcnc docs for spix are a good read as it points everything out.

Many thanks to everyone who has offered some advice. I found a single stepperonline DM860T stepper driver on marketplace to test with and I now have the x-axis wired to my 7i96 for and moving, more-or-less as expected. I have the driver and Mesa card wired for differential inputs (dir +/- and step +/-). For settings, I'm simply using 5000/5000/10000/10000.

 

For what it is worth, the timing page in the stepperonline manual lists:

• dir must be ahead of pul by 5000ns
• pulse with not less than 2500ns
• low level width not less than 2500ns
  
  
  Two quirks I've noticed:
  1. The max limit for direction hold/setup in the 'Test/Tune Axis' option is 10000, rather than the recommended 20000.
  2. Occasionally, when using 'run' on the 'Test/Tune Axis' panel, for a back and forth test of 2", the movement at the end of travel oscillates around the endpoints. It isn't consistent, it will oscillate for a little bit and then stop oscillating and then start up again. I will try and post a video of this shortly. Any insight would be greatly appreciated!