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# Changing Auto Bed Leveling (ABL) / probe settings in SimplyPrint

If your printer has a bed probe, SimplyPrint can start auto bed leveling for you and show the resulting bed mesh. This guide covers where the probe settings are, how to change the bed leveling G-code, and how to run bed leveling from the panel.

## In this guide
* [Turn on auto bed leveling for a printer](#2-turn-on-auto-bed-leveling-for-a-printer)
* [Change the bed leveling G-code](#2-change-the-bed-leveling-g-code)
* [Run auto bed leveling](#2-run-auto-bed-leveling)
* [See the bed mesh](#2-see-the-bed-mesh)
* [Which printers can do this](#2-which-printers-can-do-this)
* [Related articles](#2-related-articles)

## Turn on auto bed leveling for a printer
|| Printer settings can only be changed in the web panel, and only by members allowed to edit printer settings.

1. Open the printer's settings. See [Finding the printer settings](https://help.simplyprint.io/en/article/finding-the-printer-settings-17tbtqt/).
2. Go to the **Modifications** tab and click **Auto Bed Leveling**.
3. Tick **Printer has a probing tool**.
4. Under **Bed Leveling firmware**, pick the firmware your printer runs.
5. Click **Save changes**.

Check: open the settings again. **Printer has a probing tool** is still ticked and the **Bed Level GCODE** editor shows commands.

## Change the bed leveling G-code
The **Bed Level GCODE** editor holds the commands SimplyPrint sends when you start auto bed leveling. When you first open it, it is filled with the default for your firmware:

| Bed Leveling firmware | Main command in the default |
| --------------------- | --------------------------- |
| Marlin | `G29 T` |
| Marlin (UBL) | `G29 P1`, then `G29 P3`, then `M500` to save the mesh |
| Prusa Firmware | `G80`, then `G81` |
| Prusa Mini | `G29` |
| Klipper | `BED_MESH_CALIBRATE` |
| Klipper running OctoPrint | `BED_MESH_CALIBRATE`, then `BED_MESH_OUTPUT` |
| Duet3D / RepRapFirmware | `G29` |

To use your own commands:

1. Edit the commands in **Bed Level GCODE**, one per line. Anything after a `;` is a comment and is not sent.
2. Click **Save changes**.

||| Picking a different **Bed Leveling firmware** replaces your G-code with that firmware's default. SimplyPrint asks you to confirm with **Overwrite GCODE** first. Choose **Cancel** to keep your own G-code.

The lines starting with `@BEDLEVELVISUALIZER` in some defaults tell the OctoPrint Bed Visualizer plugin to read the mesh. Leave them in if you use OctoPrint.

## Run auto bed leveling
1. Open the printer and click **Bed leveling** in its controls.
2. Stay on the **Auto bed leveling** tab.
3. Set the nozzle and bed temperatures. They start at the temperatures of the filament loaded in the printer, or 210 °C and 60 °C if SimplyPrint doesn't know the filament. Set a temperature to 0 to skip heating.
4. Click **Start auto bed leveling**.

SimplyPrint then sends, in this order:

1. Commands that start heating the bed and nozzle, if you set temperatures. Temperatures above your printer's maximum are lowered to the maximum.
2. `G28` to home, unless your G-code already has it.
3. Commands that wait until the bed and nozzle are hot.
4. Your **Bed Level GCODE**.
5. Commands that turn the heaters off again.

Check: the button reads **Waiting for ABL to finish...** while the printer probes.

| For why heating before leveling matters, see [Why you should heat up your nozzle and bed before bed leveling](https://help.simplyprint.io/en/article/why-you-should-heat-up-your-nozzle-and-bed-before-bed-leveling-123dwhd/).

The same window has a **Manual bed leveling** tab for printers without a probe. It is not shown for printers with a round bed.

## See the bed mesh
When the printer reports a mesh, it is drawn next to the controls in the bed leveling window.

* **OctoPrint:** the mesh needs the OctoPrint plugin **Bed Visualizer**. If it is missing, the window shows **Install the Bed Visualizer plugin**. Installing takes a few minutes; don't turn the printer off or start a print meanwhile.
* **Other connections** that can't report a mesh show "The API you're using is not known, or doesn't support Bed Mesh". Bed leveling still runs.

## Which printers can do this
The **Bed leveling** button is only shown for printers SimplyPrint can send G-code to and heat, such as printers on OctoPrint, Klipper or Duet. It is not offered for Bambu Lab printers. You also need the bed leveling permission in your account.

## Related articles
* [Finding the printer settings](https://help.simplyprint.io/en/article/finding-the-printer-settings-17tbtqt/)
* [Why you should heat up your nozzle and bed before bed leveling](https://help.simplyprint.io/en/article/why-you-should-heat-up-your-nozzle-and-bed-before-bed-leveling-123dwhd/)
* [Z-Offset calibration: fine-tune your first layer remotely](https://help.simplyprint.io/en/article/z-offset-calibration-fine-tune-your-first-layer-remotely-mj4x4m/)
* [The G-code macros feature](https://help.simplyprint.io/en/article/the-g-code-macros-feature-custom-g-code-at-every-print-action-ivtt41/)