> For the complete documentation index, see [llms.txt](https://px4.gitbook.io/px4-user-guide/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://px4.gitbook.io/px4-user-guide/advanced_config/parameters.md).

# Finding/Updating Parameters

PX4 behaviour can be configured/tuned using [parameters](/px4-user-guide/advanced_config/parameter_reference.md) (e.g. [Multicopter PID gains](/px4-user-guide/airframes/frames_multicopter/config_mc/pid_tuning_guide_multicopter.md), calibration information, etc.).

The *QGroundControl Parameters* screen allows you to find and modify **any** of the parameters associated with the vehicle. The screen is accessed by clicking the **Q** application icon > **Vehicle Setup**, and then *Parameters* in the sidebar.

:::note Most of the more commonly used parameters are more conveniently set using the dedicated setup screens, as described in the [Standard Configuration](/px4-user-guide/config.md) section. The *Parameters* screen is needed when modifying less commonly modified parameters - for example while tuning a new vehicle. :::

:::warning While some parameters can be changed in flight, this is not recommended (except where explicitly stated in the guide). :::

## Finding a Parameter

You can search for a parameter by entering a term in the *Search* field. This will show you a list of all parameter names and descriptions that contain the entered substring (press **Clear** to reset the search, and use the **Show modified only** checkbox to filter out unchanged parameters).

![Parameters Search](https://4155462212-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2F-LArEa7z2SPawfl3HpCD%2Fuploads%2Fgit-blob-a97323f1337e7cb77b7ef9b7e9612b35fb89677d%2Fparameters_search.png?alt=media)

You can also browse the parameters by type and group by clicking on the buttons to the left (in the image below the *DShot* group in the *Standard* parameters is selected).

![Parameters Screen](https://4155462212-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2F-LArEa7z2SPawfl3HpCD%2Fuploads%2Fgit-blob-cc410dd25c5e5470c85f0983f4d76ca841c64c53%2Fparameters_px4.png?alt=media)

You can expand/collapse the "type" groupings as shown. Note that the groups at the bottom named *Component X* are attached [DroneCAN peripherals](/px4-user-guide/drone_parts/peripherals/dronecan.md#qgc-cannode-parameter-configuration) ("X" is the node id). [QGC can set the parameters](/px4-user-guide/drone_parts/peripherals/dronecan.md#qgc-cannode-parameter-configuration) of these peripherals if they are attached to the Flight Controller when QGC is started.

![Parameters Types - collapsed](https://4155462212-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2F-LArEa7z2SPawfl3HpCD%2Fuploads%2Fgit-blob-c53917445265c73657a108ceb66d9b582dafe719%2Fparameters_types.png?alt=media)

:::tip If you can't find an expected parameter, see the [next section](#missing). :::

## Missing Parameters

Parameters are usually not visible because either they are conditional on other parameters, or they are not present in the firmware (see below).

### Conditional Parameters

A parameter may not be displayed if it is conditional on another parameter that is not enabled.

You can usually find out what parameters are conditional by searching the [full parameter reference](/px4-user-guide/advanced_config/parameter_reference.md) and other documentation. In particular [serial port configuration parameters](/px4-user-guide/advanced_config/serial_configuration.md) depend on what service is assigned to a serial port.

### Parameter Not In Firmware

A parameter may not be present in the firmware because you're using a different version of PX4 or because you're using a build in which the associated module is not included.

New parameters are added in each PX4 version, and existing parameters are sometimes removed or renamed. You can check whether a parameter *should* be present by reviewing the [full parameter reference](/px4-user-guide/advanced_config/parameter_reference.md) for the version you're targeting. You can also search for the parameter in the source tree and in the release notes.

The other reason that a parameter might not be in firmware is if its associated module has not been included. This is a problem (in particular) for *FMUv2 firmware*, which omits many modules so that PX4 can fit into the 1MB of available flash. There are two options to solve this problem:

* Check if you can update your board to run FMUv3 firmware, which includes all modules: [Firmware > FMUv2 Bootloader Update](/px4-user-guide/config/firmware.md#bootloader)
* If your board can only run FMUv2 firmware you will need to [rebuild PX4](/px4-user-guide/development/getting_started/building_px4.md) with the missing modules enabled. You need reconfigure the PX4 firmware itself through make px4\_fmuv2\_default boardconfig where you can enabled/disable modules.

  :::note You may also need to disable other modules in order to fit the rebuilt firmware into 1MB flash. Finding modules to remove requires some trial/error and depends on what use cases you need the vehicle to meet. :::

## Changing a Parameter

To change the value of a parameter click on the parameter row in a group or search list. This will open a side dialog in which you can update the value (this dialog also provides additional detailed information about the parameter - including whether a reboot is required for the change to take effect).

![Changing a parameter value](https://4155462212-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2F-LArEa7z2SPawfl3HpCD%2Fuploads%2Fgit-blob-4440f79414d0e5980d1b0f8d51ef24d95696633c%2Fparameters_changing.png?alt=media)

:::note When you click **Save** the parameter is automatically and silently uploaded to the connected vehicle. Depending on the parameter, you may then need to reboot the flight controller for the change to take effect. :::

## Tools

You can select additional options from the **Tools** menu on the top right hand side of the screen.

![Tools menu](https://4155462212-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2F-LArEa7z2SPawfl3HpCD%2Fuploads%2Fgit-blob-08902c3290b1d59ef6d426e52b0cd670fbc5189e%2Fparameters_tools_menu.png?alt=media)

**Refresh**\
Refresh the parameter values by re-requesting all of them from the vehicle.

**Reset all to firmware defaults**\
Reset all parameters to their original default values in the firmware.

**Reset to vehicle's configuration defaults**\
Reset all parameters to their original default values for the particular selected airfame configuration.

**Load from file / Save to file**\
Load parameters from an existing file or save your current parameter settings to a file.

**Clear all RC to Param**\
This clears all associations between RC transmitter controls and parameters. For more information see: [Radio Setup > Param Tuning Channels](/px4-user-guide/config/radio.md#param-tuning-channels).

**Reboot Vehicle**\
Reboot the vehicle (required after changing some parameters).