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# UavcanParameterRequest (UORB message)

UAVCAN-MAVLink parameter bridge request type.

**TOPICS:** uavcan_parameter_request

## Fields

| Name         | Type       | Unit [Frame] | Range/Enum | Description                                                             |
| ------------ | ---------- | ------------ | ---------- | ----------------------------------------------------------------------- |
| timestamp    | `uint64`   |              |            | time since system start (microseconds)                                  |
| message_type | `uint8`    |              |            | MAVLink message type: PARAM_REQUEST_READ, PARAM_REQUEST_LIST, PARAM_SET |
| node_id      | `uint8`    |              |            | UAVCAN node ID mapped from MAVLink component ID                         |
| param_id     | `char[17]` |              |            | MAVLink/UAVCAN parameter name                                           |
| param_index  | `int16`    |              |            | -1 if the param_id field should be used as identifier                   |
| param_type   | `uint8`    |              |            | MAVLink parameter type                                                  |
| int_value    | `int64`    |              |            | current value if param_type is int-like                                 |
| real_value   | `float32`  |              |            | current value if param_type is float-like                               |

## Constants

| Name                                                                          | Type    | Value | Description                       |
| ----------------------------------------------------------------------------- | ------- | ----- | --------------------------------- |
| <a id="#MESSAGE_TYPE_PARAM_REQUEST_READ"></a> MESSAGE_TYPE_PARAM_REQUEST_READ | `uint8` | 20    | MAVLINK_MSG_ID_PARAM_REQUEST_READ |
| <a id="#MESSAGE_TYPE_PARAM_REQUEST_LIST"></a> MESSAGE_TYPE_PARAM_REQUEST_LIST | `uint8` | 21    | MAVLINK_MSG_ID_PARAM_REQUEST_LIST |
| <a id="#MESSAGE_TYPE_PARAM_SET"></a> MESSAGE_TYPE_PARAM_SET                   | `uint8` | 23    | MAVLINK_MSG_ID_PARAM_SET          |
| <a id="#NODE_ID_ALL"></a> NODE_ID_ALL                                         | `uint8` | 0     | MAV_COMP_ID_ALL                   |
| <a id="#PARAM_TYPE_UINT8"></a> PARAM_TYPE_UINT8                               | `uint8` | 1     | MAV_PARAM_TYPE_UINT8              |
| <a id="#PARAM_TYPE_INT64"></a> PARAM_TYPE_INT64                               | `uint8` | 8     | MAV_PARAM_TYPE_INT64              |
| <a id="#PARAM_TYPE_REAL32"></a> PARAM_TYPE_REAL32                             | `uint8` | 9     | MAV_PARAM_TYPE_REAL32             |
| <a id="#ORB_QUEUE_LENGTH"></a> ORB_QUEUE_LENGTH                               | `uint8` | 4     |

## Source Message

[Source file (GitHub)](https://github.com/PX4/PX4-Autopilot/blob/main/msg/UavcanParameterRequest.msg)

::: details Click here to see original file

```c
# UAVCAN-MAVLink parameter bridge request type
uint64 timestamp		# time since system start (microseconds)

uint8 MESSAGE_TYPE_PARAM_REQUEST_READ = 20	# MAVLINK_MSG_ID_PARAM_REQUEST_READ
uint8 MESSAGE_TYPE_PARAM_REQUEST_LIST = 21	# MAVLINK_MSG_ID_PARAM_REQUEST_LIST
uint8 MESSAGE_TYPE_PARAM_SET = 23		# MAVLINK_MSG_ID_PARAM_SET
uint8 message_type				# MAVLink message type: PARAM_REQUEST_READ, PARAM_REQUEST_LIST, PARAM_SET

uint8 NODE_ID_ALL = 0		# MAV_COMP_ID_ALL
uint8 node_id			# UAVCAN node ID mapped from MAVLink component ID

char[17] param_id		# MAVLink/UAVCAN parameter name
int16 param_index		# -1 if the param_id field should be used as identifier

uint8 PARAM_TYPE_UINT8 = 1	# MAV_PARAM_TYPE_UINT8
uint8 PARAM_TYPE_INT64 = 8	# MAV_PARAM_TYPE_INT64
uint8 PARAM_TYPE_REAL32 = 9	# MAV_PARAM_TYPE_REAL32
uint8 param_type		# MAVLink parameter type

int64 int_value			# current value if param_type is int-like
float32 real_value		# current value if param_type is float-like

uint8 ORB_QUEUE_LENGTH = 4
```

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