Can't figure out BLTouch offset
June 10, 2018 12:33AM
I cannot figure out how to get the leveling values produced by the BLTouch to register. I'm using a custom 3D printer and Marlin bugfix 2.0.x. This is what happens:

G28 to home printer
G29 and the four corners of the bed are measured.
echo: M420 S1 Z0.00
echo: G29 W I1 J1 Z2.43446
echo: G29 W I2 J1 Z2.16985
echo: G29 W I1 J2 Z3.25292
echo: G29 W I2 J2 Z1.50892

I start the print and the print head is about 4mm above the bed. So I assume its the
#define Z_PROBE_OFFSET_FROM_EXTRUDER 2.4 // Z offset: -below +above [the nozzle] Line 768 Configuration.h.

Just to test, I set this value to 10, so
#define Z_PROBE_OFFSET_FROM_EXTRUDER 10 // Z offset: -below +above [the nozzle]

I restart the print and again the nozzle is about 4mm above the bed.

Next, I change the M851 Z offset from -2.7 to -10.

EEPROM is enabled for sure. When I send M503 I get my updated values but they seem to have no effect.

I restart the print and again the nozzle is about 4mm above the bed. What value do I need to change to get the nozzle to adjust for this offset?

Thanks in advance.

Edited 1 time(s). Last edit at 06/10/2018 12:40AM by Jeffsg605.
Re: Can't figure out BLTouch offset
July 09, 2018 04:21PM
I'm not sure but maybe its the slicer. Please tell me your custom start gcode. Had a similar issue and i was able to fix it by modifying the start gcode. Or maybe you have set the offset in your slicer.

Edited 1 time(s). Last edit at 07/09/2018 04:22PM by Kutulu.
Re: Can't figure out BLTouch offset
July 09, 2018 05:34PM
After doing a G29, send a G1 Z0 ,does the nozzle stop at Z0 or is it above/below the bed ?
Re: Can't figure out BLTouch offset
July 09, 2018 08:14PM
After any change to the default settings... You need to do a M502 (to load the default settings) followed by a M500 (to save the updated settings).
If you don't do that... The behavior won't change because it keeps using the saved values in the EEPROM.
Sorry, only registered users may post in this forum.

Click here to login