Delta TMC2130 sensorless homing Marlin 2.0

Hello everyone,

yesterday I tried Marlin 2.0 on my delta machine. I use the einsy rambo - yes, very exotic for delta machines. I also enabled sensorless homing:

I played around with the sensitivity but the Z axis keeps crashing. X and Y axis homing works fine. Any Ideas what to do?

Also homing a single axis with "G28 X" just homes all axis - is this command disabled on delta machines?

Thanks for your help!

Same issue with Marlin 1.1.9

Is this feature not ready for delta machines or did I miss something in the config file?

Some Homing Help for Delta.
Im using SKR v1.3 with TMC2130 (same as Einsy Rambo) and have also been struggling over getting Marlin 2.0 to Sensorless Home my Delta.
I had the same issue where the X and Y homed perfectly, but Z would just crash unless I used a physical endstop.
What fixed it for me was commenting out the #define USE_ZMIN_PLUG. This made the Z tower home the same as the others.
I also found that #define MINIMUM_STEPPER_PULSE 2 was Wrong!.
2 is NOT the correct pulse value for TMC2130s, 0 is..I commented this line out all together and used default value.
This was only thing that actually made sensorless homing trigger at all.
Until I commented this out, nothing was making a difference and StallGuard was never triggering.

Also, the homing code for Delta is not correct for Sensorless homing. See Thinkyhead's comment from Mar 17 2018. [github.com]
This is still incorrect in the latest Marlin 2.0. However it is now in the delta.ccp file.
This causes the printer to move all carriages only a tiny bit (juts a few microsteps) before homing individual towers.
This is fine if the carriages are close to the top, but if they're not, X starts to move up alone and jams up the printer.

I also noticed that if you have StallGuard Threshold set just 1 point to low, you will have odd homing behavior.
If X gets home first, Y just stops, then Z homes normally.
If Y gets home first X stops, then Z homes normally.
So either way, I end up with one axis not homed, and the other 2 homed

Anyway, I Hope some/any of this helps someone.