After trying to solve this for the whole weekend I've run out of ideas.
I've fitted an BLTouch to my Ender-3 with an SKR mini e3 V2.0 board, firmware is Marlin 2.0.
My issue is the following:
when I do autohome (
G28) it uses the Z-Probe (BLTouch) to home (this is expected).
I then set Z Probe offset to 0 (using
M851 Z0) and move Z down until it the nozzle touches a piece of paper.
I then set the Probe Z offset to whatever value Z is at (
M851 Z-4.10), save the settings to EEPROM and restart the machine. When doing another
G28 and moving Z to 0 afterwards the distance is perfectly the same. This is repeatable.
However when I do
G29 it measures the bed to be sitting around -1.9 mm, therefore moving Z to 0 will crash the nozzle to the bed. I can change my Probe Z offset have this fitting (
M851 Z-2.20), however then the nozzle sits ~2 mm above the bed when doing another
G28 with "Bed Leveling" disabled.
All of this is perfectly repeatable, so I think my I've got something off in my Marlin configuration, but can't find anything wrong.
What I've tried so far:
- Setting the Z offset as default in config -> this yields the same result as saving it to EEPROM
- Reflashing the firmware and resetting the EEPROM -> this didn't change anything
- Connecting the probe as Z-Endstop and as Z-Probe -> after matching the configuration (setting/unsetting Z_MIN_PROBE_USES_Z_MIN_ENDSTOP_PIN) it just gave the same result.
Did anyone encounter this issue before or can give me any idea how to fix this? Any help would be appreciated.
EDIT: I've just flashed the precompiled stock firmware from the BTT Github and it works. So im quite sure i've got something wrong in my config. But since I can't find the configuration.h for that .bin file, I can't realy compare both