Automatic bed leveling settings

netzmark

Hi,

I have added BLtouch and trying to understand how works the probe grid setup.

Marlin 1.1.9 and

#define AUTO_BED_LEVELING_UBL

I have the sensor pin 36mm behind and 6mm to the right from the nozzle.

#define X_PROBE_OFFSET_FROM_EXTRUDER 6  // X offset: -left  +right  [of the nozzle]
#define Y_PROBE_OFFSET_FROM_EXTRUDER 36  // Y offset: -front +behind [the nozzle]
#define Z_PROBE_OFFSET_FROM_EXTRUDER -0.85   // Z offset: -below +above  [the nozzle]

// Certain types of probes need to stay away from edges
#define MIN_PROBE_EDGE 10

  // Set the boundaries for probing (where the probe can reach).
  #define LEFT_PROBE_BED_POSITION MIN_PROBE_EDGE
  #define RIGHT_PROBE_BED_POSITION (X_BED_SIZE - MIN_PROBE_EDGE)
  #define FRONT_PROBE_BED_POSITION MIN_PROBE_EDGE
  #define BACK_PROBE_BED_POSITION (Y_BED_SIZE - MIN_PROBE_EDGE)

// The size of the print bed
#define X_BED_SIZE 305
#define Y_BED_SIZE 305

// Travel limits (mm) after homing, corresponding to endstop positions.
#define X_MIN_POS -5 // thanks DaHai.
#define Y_MIN_POS 0
#define Z_MIN_POS 0
#define X_MAX_POS X_BED_SIZE
#define Y_MAX_POS Y_BED_SIZE
#define Z_MAX_POS 320

  //===========================================================================
  //========================= Unified Bed Leveling ============================
  //===========================================================================
  #define MESH_INSET 1              // Set Mesh bounds as an inset region of the bed
  #define GRID_MAX_POINTS_X 10      // Don't use more than 15 points per axis, implementation limited.
 
      (  1,303)                                                              (303,303)
        0       1       2       3       4       5       6       7       8       9
 9 |   .       .       .       .       .       .       .       .       .       .
   |
 8 |   .     -0.193  -0.180  -0.209  -0.208  -0.206  -0.184  -0.114  -0.051    .
   |
 7 |   .     -0.193  -0.199  -0.210  -0.213  -0.194  -0.202  -0.137  -0.033    .
   |
 6 |   .     -0.180  -0.197  -0.187  -0.196  -0.194  -0.177  -0.129  -0.012    .
   |
 5 |   .     -0.152  -0.169  -0.172  -0.174  -0.184  -0.178  -0.151  -0.043    .
   |
 4 |   .     -0.133  -0.160  -0.161 [-0.229] -0.198  -0.191  -0.154  -0.037    .
   |
 3 |   .     -0.111  -0.144  -0.149  -0.169  -0.206  -0.191  -0.164  -0.043    .
   |
 2 |   .     -0.099  -0.101  -0.147  -0.182  -0.217  -0.198  -0.146  -0.067    .
   |
 1 |   .       .       .       .       .       .       .       .       .       .
   |
 0 |   .       .       .       .       .       .       .       .       .       .
        0       1       2       3       4       5       6       7       8       9
    (  1,  1)                                                              (303,  1)

So one left, right, upper and two bottom raws/cooumns are not done.

After many experiments giving nothing I have changed:

// Travel limits (mm) after homing, corresponding to endstop positions.
#define X_MIN_POS -5 // thanks DaHai.
#define Y_MIN_POS -2 // <<------------------------------this is it
#define Z_MIN_POS 0
#define X_MAX_POS X_BED_SIZE
#define Y_MAX_POS Y_BED_SIZE
#define Z_MAX_POS 320

and got:

      (  1,303)                                                              (303,303)
        0       1       2       3       4       5       6       7       8       9
 9 |   .       .       .       .       .       .       .       .       .       .
   |
 8 |   .     -0.193  -0.180  -0.209  -0.208  -0.206  -0.184  -0.114  -0.051    .
   |
 7 |   .     -0.193  -0.199  -0.210  -0.213  -0.194  -0.202  -0.137  -0.033    .
   |
 6 |   .     -0.180  -0.197  -0.187  -0.196  -0.194  -0.177  -0.129  -0.012    .
   |
 5 |   .     -0.152  -0.169  -0.172  -0.174  -0.184  -0.178  -0.151  -0.043    .
   |
 4 |   .     -0.133  -0.160  -0.161 [-0.229] -0.198  -0.191  -0.154  -0.037    .
   |
 3 |   .     -0.111  -0.144  -0.149  -0.169  -0.206  -0.191  -0.164  -0.043    .
   |
 2 |   .     -0.099  -0.101  -0.147  -0.182  -0.217  -0.198  -0.146  -0.067    .
   |
 1 |   .     -0.011  -0.107  -0.053  -0.113  -0.129  -0.144  -0.190  -0.090    .
   |
 0 |   .       .       .       .       .       .       .       .       .       .
        0       1       2       3       4       5       6       7       8       9
    (  1,  1)                                                              (303,  1)

So in the bottom I have now only one raw not probed.

Definitely travel limit Y is here making "something".

Another change:

#define GRID_MAX_POINTS_X 7      // Don't use more than 15 points per axis, implementation limited.

SENDING:G29 T
Bed Topography Report:
    (  1,303)                                      (303,303)
        0       1       2       3       4       5       6
 6 |   .       .       .       .       .       .       .
   |
 5 |   .     -0.214  -0.207  -0.183  -0.223  -0.129    .
   |
 4 |   .     -0.183  -0.170  -0.191  -0.203  -0.103    .
   |
 3 |   .     -0.136  -0.147 [-0.244] -0.162  -0.098    .
   |
 2 |   .     -0.136  -0.119  -0.171  -0.160  -0.128    .
   |
 1 |   .     -0.093  -0.164  -0.150  -0.207  -0.152    .
   |
 0 |   .       .       .       .       .       .       .
        0       1       2       3       4       5       6
    (  1,  1)                                      (303,  1)

And I really have 7x7 declared probes but made only 5x5.

Can aybody let me understand how this works?

What is counting the grid size and what to do to get really probed 7x7 or 10x10?