> For the complete documentation index, see [llms.txt](https://docs.arkelectron.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.arkelectron.com/products/sensor/ark-flow-mr/ardupilot-instructions.md).

# Ardupilot Instructions

### Wiring <a href="#wiring" id="wiring"></a>

The ARK Flow MR 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 Flow MR's second CAN connector.

### Mounting <a href="#mounting" id="mounting"></a>

The recommended mounting orientation is with the connectors on the board pointing towards **back of vehicle**, as shown in the following picture.

![ARK Flow align with Pixhawk](https://docs.px4.io/main/assets/ark_flow_orientation.auMVvxJ0.png)

### Flight Controller Parameters

Connect the ARK Flow MR to the flight controller's CAN port and set the following parameters. Reboot the flight controller after setting them.

#### Required

| Parameter                                                                              | Value | Description              |
| -------------------------------------------------------------------------------------- | ----- | ------------------------ |
| [CAN\_P1\_DRIVER](https://ardupilot.org/copter/docs/parameters.html#can-p1-driver)     | 1     | Enable CAN port 1 driver |
| [CAN\_D1\_PROTOCOL](https://ardupilot.org/copter/docs/parameters.html#can-d1-protocol) | 1     | Set protocol to DroneCAN |
| [FLOW\_TYPE](https://ardupilot.org/copter/docs/parameters.html#flow-type)              | 6     | DroneCAN optical flow    |

#### Optional

To use the onboard lidar:

| Parameter                                                                              | Value       | Description                  |
| -------------------------------------------------------------------------------------- | ----------- | ---------------------------- |
| [RNGFND1\_TYPE](https://ardupilot.org/copter/docs/parameters.html#rngfnd1-type)        | 24          | DroneCAN rangefinder         |
| [RNGFND1\_MAX](https://ardupilot.org/copter/docs/parameters.html#rngfnd1-max)          | 5000        | Maximum range in cm (50 m)   |
| [RNGFND1\_ADDR](https://ardupilot.org/copter/docs/parameters.html#rngfnd1-addr)        | *sensor ID* | Sensor ID of the rangefinder |
| [RNGFND1\_RECV\_ID](https://ardupilot.org/copter/docs/parameters.html#rngfnd1-recv-id) | *node ID*   | CAN node ID of the sensor    |

To compensate for sensor placement (see [sensor offset compensation](https://ardupilot.org/copter/docs/common-sensor-offset-compensation.html#common-sensor-offset-compensation)):

| Parameter                                                                                                                                                                                                                                  | Description                                                    |
| ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------ | -------------------------------------------------------------- |
| [FLOW\_POS\_X](https://ardupilot.org/copter/docs/parameters.html#flow-pos-x) / [FLOW\_POS\_Y](https://ardupilot.org/copter/docs/parameters.html#flow-pos-y) / [FLOW\_POS\_Z](https://ardupilot.org/copter/docs/parameters.html#flow-pos-z) | ARK Flow MR offset from the vehicle center of gravity (meters) |

### 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     |
| `CANNODE_PUB_IMU` | Set to `1` to publish `RawIMU` messages on the CAN bus |

### Additional Notes

* [FlowHold](https://ardupilot.org/copter/docs/flowhold-mode.html#flowhold-mode) does not require the use of a rangefinder.

#### ArduPilot Setup Instructions

{% embed url="<https://ardupilot.org/copter/docs/common-optical-flow-sensor-setup.html>" fullWidth="false" %}
Sensor Setup Instructions
{% endembed %}


---

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