Unified Bed Leveling - What am I doing wrong? (1 reply)

Hi,

Trying to get my first decent print in my newly built hypercube-alike printer.
Since it has a big bed (300 x 300) I'm using UBL (Unified bed leveling). I'm using a bltouch clone as Z sensor.
I've set an offset of X40 Y4 from the extruder to the bltouch tip.

Following the information from [marlinfw.org] this is what I did:

- Flashed the firmware and reset the board
- Issued M502 and M500
- G28 to home XY
- G29 P1 - The printer starts probing some areas but in a disordered way. Instead of doing sequential points it's traveling back and forth which makes the whole process to take longer. Also, the LCD mention that x/100 points are tested but it seems only 64 are tested (it stops at 64/100).
- G29 P3 T - I do it a couple of times, I have no idea how many times I have to do it neither why.
- G29 T - I get the values below

Recv: Recv: Bed Topography Report:
Recv: 
Recv:     (  1,280)                                                              (295,280)
Recv:         0       1       2       3       4       5       6       7       8       9
Recv:  9 |   .     -1.232  -1.232  -0.932  -0.671  -0.364  -0.050  +0.271  +0.610  +0.949
Recv:    |
Recv:  8 |   .     -1.102  -1.102  -0.824  -0.530  -0.245  +0.031  +0.329  +0.644  +0.959
Recv:    |
Recv:  7 |   .     -0.970  -0.970  -0.704  -0.381  -0.162  +0.100  +0.386  +0.669  +0.951
Recv:    |
Recv:  6 |   .     -0.850  -0.850  -0.591  -0.321  -0.054  +0.189  +0.443  +0.720  +0.997
Recv:    |
Recv:  5 |   .     -0.706  -0.706  -0.436  -0.181  +0.053  +0.279  +0.526  +0.812  +1.099
Recv:    |
Recv:  4 |   .     -0.565  -0.565  -0.289  -0.050  +0.204  +0.408  +0.664  +0.894  +1.124
Recv:    |
Recv:  3 |   .     -0.346  -0.346  -0.139  +0.124  +0.370  +0.578  +0.799  +1.024  +1.249
Recv:    |
Recv:  2 |   .     -0.210  -0.210  +0.044  +0.296  +0.501  +0.709  +0.954  +1.139  +1.324
Recv:    |
Recv:  1 |   .     -0.049  -0.049  +0.201  +0.416  +0.661  +0.880  +1.076  +1.265  +1.454
Recv:    |
Recv:  0 |   .    [+0.113] +0.113  +0.359  +0.536  +0.821  +1.051  +1.199  +1.391  +1.584
Recv:         0       1       2       3       4       5       6       7       8       9
Recv:     (  1,  1)                                                              (295,  1)
Recv: 
Recv: ok
Recv:  T:2

- G29 S1 - to store the vaules in eeprom
- G29 F 10.0 - Not sure I understand what this is for (would it be that there will be no more bed leveling compensation from 10mm high onwards?)
- G29 A - to activate UBL
- M500 to save settings in eeprom
- reset the board
- G28 to home XY
- G29 T to see the values from above - Confirm they are there and not zero
- Load a test file to print.
- The result of first layer :



As it can be seen, something is wrong with the bed leveling. It's too high on the right and too low on the left.
I confirmed that the Z axis move as the extruder travels around, so it is supposedly doing his stuff, but likely to be using the wrong values....


Any idea of what am I doing wrong?

Thanks,
Joaoabs