--- tag: g029g2 title: Bed Leveling (Linear) brief: Probe the bed and enable leveling compensation. author: thinkyhead requires: AUTO_BED_LEVELING_LINEAR group: calibration related: [ M420 ] codes: [ G29 ] notes: - Any arguments left out of `G29` will use the default values set in `Configuration.h`. - "[`G28`](/docs/gcode/G028.html) disables bed leveling. Follow with `M420 S` to turn leveling on, or use `RESTORE_LEVELING_AFTER_G28` to automatically keep leveling on after [`G28`](/docs/gcode/G028.html)." - To save time and machine wear, save your matrix to EEPROM with [`M500`](/docs/gcode/M500.html) and in your slicer's "Starting G-code" replace `G29` with `M420 S1` to enable your last-saved matrix. parameters: - tag: A optional: true description: Abort leveling procedure in-progress (`PROBE_MANUALLY`) values: - type: bool - tag: C optional: true description: Create a fake grid for testing. (`DEBUG_LEVELING_FEATURE`) values: - type: bool - tag: O type: bool optional: true description: Optional. If leveling is already enabled then exit without leveling. (1.1.9) - tag: Q optional: true description: Query the current leveling state (`PROBE_MANUALLY`, `DEBUG_LEVELING_FEATURE`) values: - type: bool - tag: X optional: true description: Set the number of columns (in X) that will be probed. values: - type: int - tag: Y optional: true description: Set the number of rows (in Y) that will be probed. values: - type: int - tag: P optional: true description: Set the size of the square grid that will be probed - P x P points values: - type: int - tag: S optional: true description: Set the XY travel speed between probe points. values: - tag: rate type: float - tag: E optional: true description: | - By default G29 will engage the Z probe, test the bed, then disengage. - Include "E" to engage/disengage the Z probe for each sample. - There's no extra effect if you have a fixed Z probe. (without `PROBE_MANUALLY`) values: - type: bool - tag: D optional: true description: Dry-Run mode. Just probe the grid but don't update the bed leveling data values: - type: bool - tag: T optional: true description: Generate a Bed Topology Report values: - type: bool - tag: H optional: true description: Set the square width and height of the area to probe. values: - tag: linear type: float - tag: F optional: true description: Set the front limit of the probing grid. values: - tag: linear type: float - tag: B optional: true description: Set the back limit of the probing grid. values: - tag: linear type: float - tag: L optional: true description: Set the left limit of the probing grid. values: - tag: linear type: float - tag: R optional: true description: Set the right limit of the probing grid. values: - tag: linear type: float - tag: J optional: true description: Jettison the leveling data stored in SRAM and turn off leveling compensation. Data in EEPROM is not affected. values: - type: bool - tag: V optional: true description: Set the verbose level. Level 2 and up act like 'T'. values: - type: int tag: 0-4 examples: - pre: Automatic Probing examples post: '`G29` is most commonly used without any arguments. This uses the defaults set in `Configuration.h`.' code: G29 ; probe and enable - post: Probe a 5x5 matrix. code: G29 P5 ; 5x5 matrix - post: 'Probe a 4x8 matrix from `X50` `Y50` to `X150` `Y150`, printing a full report.' code: G29 X4 Y8 L50 R150 F50 B150 T V4 - pre: Manual Probing example post: 'Each `G29` command goes to the next step until the whole procedure is done. The `V1` parameter provides a progress report.' code: - G29 V1 ; Ready! Go to Point 1, wait... - G29 V1 ; Store Z, go to Point 2, wait... - G29 V1 ; Store Z, go to Point 3, wait... - G29 V1 ; Store Z, go to Point 4, wait... - G29 V1 ; Store Z, go to Point 5, wait... - G29 V1 ; Store Z, go to Point 6, wait... - G29 V1 ; Store Z, go to Point 7, wait... - G29 V1 ; Store Z, go to Point 8, wait... - G29 V1 ; Store Z, go to Point 9, wait... - G29 V1 ; Store Z. Calculate matrix. Activate. --- Automatic (Linear) Bed Leveling probes the bed in a grid and enables bed leveling compensation using a matrix to compensate for bed tilt, applying a "least-squares" approximation. The printer must be homed with [`G28`](/docs/gcode/G028.html) before `G29`. #### Automatic Probing Using an electronic probe Marlin can probe the entire grid with a single `G29` command. See parameter descriptions and examples below for details. #### Manual Probing {% details %} Auto Bed Leveling now includes a `PROBE_MANUALLY` option for systems lacking a probe. **`PROBE_MANUALLY` adds these parameters to `G29`:** - `Q` : Query leveling and `G29` state - `A` : Abort current leveling procedure To do manual probing simply repeat `G29` until the procedure is complete. The first `G29` accepts the same parameters , shown in the [Usage](#usage-g029g2) section below. The exact parameters available will depend on which style of bed leveling is enabled. (***Note:** UBL parameters are not covered on this page unless they coincide. See the [`G29` for UBL](/docs/gcode/G029-ubl.html) page for a full list of its options.*) **Before probing the bed:** 1. Use `G29 Q` to get the current status. If `G29` isn't idle, abort with `G29 A`. 2. Use `M420 V` to view leveling data. You can send `M420 S1` to use the existing data. **To probe the bed using G-code:** 1. Use `G29` to move to the first point for Z adjustment. 2. Adjust Z so a piece of paper can just pass under the nozzle. 3. Use `G29` to save the Z value and move to the next point. 4. Repeat steps 3-4 until completed. 5. Use [`M500`](/docs/gcode/M500.html) to save the leveling data to EEPROM, if desired. **To probe the bed using your LCD controller:** (Requires `LCD_BED_LEVELING`) 1. Select the `Level Bed` sub-menu, then choose `Level Bed` (not `Cancel`). 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. {% enddetails %}