# PX4 Instructions

## Hardware Setup

### Wiring

The ARK DIST is connected to the CAN bus using a Pixhawk standard 4 pin JST-GH cable. For more information, refer to the [CAN Wiring](https://docs.px4.io/main/en/can/#wiring) instructions.

Multiple sensors can be connected by plugging additional sensors into the ARK DIST's second CAN connector.

The ARK DIST can also be connected with UART and communicates over MAVLink sending the [DISTANCE\_SENSOR](https://mavlink.io/en/messages/common.html#DISTANCE_SENSOR) message.

### Firmware

ARK DIST runs the [PX4 DroneCAN Firmware](https://docs.px4.io/main/en/dronecan/px4_cannode_fw.html). As such, it supports firmware update over the CAN bus and [dynamic node allocation](https://docs.px4.io/main/en/dronecan/#node-id-allocation).

## CAN Configuration

### Flight Controller Parameters

Set the following in *QGroundControl* and reboot the flight controller.

#### Required

| Parameter                                                                                                  | Value              | Description                                  |
| ---------------------------------------------------------------------------------------------------------- | ------------------ | -------------------------------------------- |
| [UAVCAN\_ENABLE](https://docs.px4.io/main/en/advanced_config/parameter_reference.html#UAVCAN_ENABLE)       | 2                  | Enable DroneCAN with dynamic node allocation |
| [UAVCAN\_SUB\_RNG](https://docs.px4.io/main/en/advanced_config/parameter_reference.html#UAVCAN_SUB_RNG)    | 1                  | Subscribe to DroneCAN range finder messages  |
| [UAVCAN\_RNG\_MIN](https://docs.px4.io/main/en/advanced_config/parameter_reference.html#UAVCAN_RNG_MIN)    | 0                  | Min reported range                           |
| [UAVCAN\_RNG\_MAX](https://docs.px4.io/main/en/advanced_config/parameter_reference.html#UAVCAN_RNG_MAX)    | *max sensor range* | Max reported range                           |
| [EKF2\_RNG\_A\_HMAX](https://docs.px4.io/main/en/advanced_config/parameter_reference.html#EKF2_RNG_A_HMAX) | *max sensor range* | Max range used by the EKF                    |
| [EKF2\_RNG\_QLTY\_T](https://docs.px4.io/main/en/advanced_config/parameter_reference.html#EKF2_RNG_QLTY_T) | 0.2                | Range finder quality time                    |

### CAN Node Parameters

Set the following on the sensor and reboot the node. CAN node parameters can be configured using either:

* [QGroundControl](https://docs.px4.io/main/en/dronecan/#qgc-cannode-parameter-configuration) — each CAN node appears as a separate *Component X* entry under **Vehicle Settings > Parameters**.
* The [DroneCAN GUI Tool](/knowledge-base/knowledge-base/dronecan-gui-tool-guide.md).

#### Optional

| Parameter      | Description                                        |
| -------------- | -------------------------------------------------- |
| `CANNODE_TERM` | Set to `1` if this is the last node on the CAN bus |

## UART/MAVLink Configuration

### Flight Controller Parameters

Set the following in *QGroundControl* and reboot the flight controller.

#### Required

| Parameter                                                                                                  | Value              | Description                                     |
| ---------------------------------------------------------------------------------------------------------- | ------------------ | ----------------------------------------------- |
| [MAV\_X\_CONFIG](https://docs.px4.io/main/en/advanced_config/parameter_reference.html#MAV_0_CONFIG)        | *port*             | Port the sensor is connected to                 |
| [MAV\_X\_FORWARD](https://docs.px4.io/main/en/advanced_config/parameter_reference.html#MAV_0_FORWARD)      | 0                  | Disable MAVLink forwarding on this port         |
| [MAV\_X\_MODE](https://docs.px4.io/main/en/advanced_config/parameter_reference.html#MAV_0_MODE)            | 7 or 13            | Minimal or Low Bandwidth — reduces memory usage |
| [SER\_X\_BAUD](https://docs.px4.io/main/en/advanced_config/parameter_reference.html#SER_TEL1_BAUD)         | 115200             | Baud rate for the MAVLink port                  |
| [EKF2\_RNG\_A\_HMAX](https://docs.px4.io/main/en/advanced_config/parameter_reference.html#EKF2_RNG_A_HMAX) | *max sensor range* | Max range used by the EKF                       |
| [EKF2\_RNG\_QLTY\_T](https://docs.px4.io/main/en/advanced_config/parameter_reference.html#EKF2_RNG_QLTY_T) | 0.2                | Range finder quality time                       |


---

# Agent Instructions: Querying This Documentation

If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question.

Perform an HTTP GET request on the current page URL with the `ask` query parameter:

```
GET https://docs.arkelectron.com/products/sensor/ark-dist/px4-instructions.md?ask=<question>
```

The question should be specific, self-contained, and written in natural language.
The response will contain a direct answer to the question and relevant excerpts and sources from the documentation.

Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.