G29 - Bed Leveling (Manual)

Description

Mesh Bed Leveling (MBL) allows interactively measuring a Z height mesh without a bed probe. The only tool required is a piece of paper or a feeler gauge. MBL uses the mesh to compensate for variations in height across the bed.

Mesh Bed Leveling from the host:

  1. Use G29 S0 to get the current status and mesh. If there’s an existing mesh, you can send M420 S1 to use it.
  2. Use G29 S1 to move to the first point for Z adjustment.
  3. Adjust Z so a piece of paper can just pass under the nozzle.
  4. Use G29 S2 to save the Z value and move to the next point.
  5. Repeat steps 3-4 until completed.
  6. Use M500 to save the mesh to EEPROM, if desired.

Mesh Bed Leveling using an LCD controller: (Requires LCD_BED_LEVELING)

  1. Select Level Bed then choose Level Bed (not Cancel) in the sub-menu.
  2. Wait for Homing XYZ to complete.
  3. When Click to Begin appears, press the controller button to move to the first point.
  4. Use the controller wheel to adjust Z so that a piece of paper can just pass under the nozzle.
  5. Press the controller button to save the Z value and move to the next point.
  6. Repeat steps 4-5 until completed.
  7. Use Control > Store memory to save the mesh to EEPROM, if desired.

Notes

Requires the MESH_BED_LEVELING option in Configuration.h.

Similar to AUTO_BED_LEVELING_BILINEAR with PROBE_MANUALLY but uses less SRAM.

For automatic probe-based leveling enable one of the AUTO_BED_LEVELING_* options instead.

G28 disables bed leveling. Follow with M420 S to turn leveling on, or use RESTORE_LEVELING_AFTER_G28 to automatically keep leveling on after G28.

Parameters

G29 [I<index>] [J<index>] S<0|1|2|3|4|5> [X<count>] [Y<count>] [Z<linear>]
[I<index>]

(Marlin 2.x) With S3, the (0…n-1) X index of the mesh value to modify.
[J<index>]

(Marlin 2.x) With S3, the (0…n-1) Y index of the mesh value to modify.
S<0|1|2|3|4|5>
  • S0:

    Produce a mesh report (see examples below).

  • S1:

    Start probing mesh points.

  • S2:

    Probe the next mesh point.

  • S3:

    Manually modify a single point with X Y Z parameters. (See also M421.)

  • S4:

    Set a global Z offset. Positive values are away from the bed; negative values are closer.

  • S5:

    Reset and disable mesh.
[X<count>]

(Marlin 1.x) With S3, the (1…n) X count of the mesh value to modify.
[Y<count>]

(Marlin 1.x) With S3, the (1…n) Y count of the mesh value to modify.
[Z<linear>]

With S3, the new mesh Z value.

Examples

S0 mesh report:

> S0
Num X,Y: 3,3
Z offset: 0
Measured points:
       0      1       2
0 +0.011 -0.020  -0.026
1 +0.017 +0.002  -0.019
2 +0.022 -0.030  -0.013

(Marlin 1.x) Modify some mesh points and view the new mesh:

> S3 X3 Y3 Z0.042
> S3 X2 Y2 Z-0.666
> S0
Num X,Y: 3,3
Z offset: 0
Measured points:
       0      1       2
0 +0.011 -0.020  -0.026
1 +0.017 -0.666  -0.019
2 +0.022 -0.030  +0.042

(Marlin 2.x) Modify some mesh points and view the new mesh:

> S3 I2 J2 Z0.042
> S3 I1 J1 Z-0.666
> S0
3x3 mesh. Z offset: 0
Measured points:
       0      1       2
0 +0.011 -0.020  -0.026
1 +0.017 -0.666  -0.019
2 +0.022 -0.030  +0.042