# 查找/修改参数

## 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).

You can also browse the parameters by group by clicking on the buttons to the left (in the image below the Battery Calibration group is selected).

## 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).

### 受条件限制的参数

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 and other documentation. In particular serial port configuration parameters depend on what service is assigned to a serial port.

### 固件中没有的参数

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 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:

• 检查你的控制板是否可以升级到包含了所有模块的FMUv3固件：固件 > FMUv2 Bootloader 升级
• 如果你的控制板只能运行FMUv2固件，你就要引入确实的模块后重生成PX4。 在boards/px4/fmu-v2/default.cmake文件中看到注释掉的模块:

  DRIVERS
#barometer # 全部支持的气压计驱动
barometer/ms5611
#batt_smbus
#camera_capture >


Note 您可能还需要禁用其他的模块才能使重生成的固件适于1MB的闪存. 找到可以移除的模块需要一些试错， 还取决于你要求载具达到哪些使用案例。

## 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).

## 工具（Tools）菜单

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

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

Reset all to defaults
Reset all parameters to their original default values.

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

Clear RC to Param
This clears all associations between RC transmitter controls and parameters. For more information see: Radio Setup > Param Tuning Channels.

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