Modbus - IMU Brick 2.0 – Tinkerforge

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# Modbus - IMU Brick 2.0

Note

This Brick is currently in the prototype stage and the software/hardware as well as the documentation is in an incomplete state.

This is the description of the Modbus protocol for the IMU Brick 2.0. General information and technical specifications for the IMU Brick 2.0 are summarized in its hardware description.

## API

A general description of the Modbus protocol structure can be found here.

### Basic Functions

`BrickIMUV2.``get_orientation`

  Function ID: | 5
  Request: | empty payload

  Response:

  - heading -- int16
  - roll -- int16
  - pitch -- int16

  Returns the current orientation (heading, roll, pitch) of the IMU Brick as Euler angles in 1/16 degree. Note that Euler angles always experience a gimbal lock.

  We recommend that you use quaternions instead.

  The rotation angle has the following ranges:

  - heading: 0° to 360°
  - roll: -90° to +90°
  - pitch: -180° to +180°

  If you want to get the orientation periodically, it is recommended to use the callback `CALLBACK_ORIENTATION` and set the period with `set_orientation_period`.

`BrickIMUV2.``get_linear_acceleration`

  Function ID: | 6
  Request: | empty payload

  Response:

  - x -- int16
  - y -- int16
  - z -- int16

  Returns the linear acceleration of the IMU Brick for the x, y and z axis in 1/100 m/s².

  The linear acceleration is the acceleration in each of the three axis of the IMU Brick with the influences of gravity removed.

  It is also possible to get the gravity vector with the influence of linear acceleration removed, see `get_gravity_vector`.

  If you want to get the linear acceleration periodically, it is recommended to use the callback `CALLBACK_LINEAR_ACCELERATION` and set the period with `set_linear_acceleration_period`.

`BrickIMUV2.``get_gravity_vector`

  Function ID: | 7
  Request: | empty payload

  Response:

  - x -- int16
  - y -- int16
  - z -- int16

  Returns the current gravity vector of the IMU Brick for the x, y and z axis in 1/100 m/s².

  The gravity vector is the acceleration that occurs due to gravity. Influences of additional linear acceleration are removed.

  It is also possible to get the linear acceleration with the influence of gravity removed, see `get_linear_acceleration`.

  If you want to get the gravity vector periodically, it is recommended to use the callback `CALLBACK_GRAVITY_VECTOR` and set the period with `set_gravity_vector_period`.

`BrickIMUV2.``get_quaternion`

  Function ID: | 8
  Request: | empty payload

  Response:

  - w -- int16
  - x -- int16
  - y -- int16
  - z -- int16

  Returns the current orientation (w, x, y, z) of the IMU Brick as quaternions.

  You have to divide the returns values by 16383 (14 bit) to get the usual range of -1.0 to +1.0 for quaternions.

  If you want to get the quaternions periodically, it is recommended to use the callback `CALLBACK_QUATERNION` and set the period with `set_quaternion_period`.

`BrickIMUV2.``get_all_data`

  Function ID: | 9
  Request: | empty payload

  Response:

  - acceleration -- int16[3]
  - magnetic_field -- int16[3]
  - angular_velocity -- int16[3]
  - euler_angle -- int16[3]
  - quaternion -- int16[4]
  - linear_acceleration -- int16[3]
  - gravity_vector -- int16[3]
  - temperature -- int8
  - calibration_status -- uint8

  Return all of the available data of the IMU Brick.

  - acceleration in 1/100 m/s² (see `get_acceleration`)
  - magnetic field in 1/16 µT (see `get_magnetic_field`)
  - angular velocity in 1/16 °/s (see `get_angular_velocity`)
  - Euler angles in 1/16 ° (see `get_orientation`)
  - quaternion 1/16383 (see `get_quaternion`)
  - linear acceleration 1/100 m/s² (see `get_linear_acceleration`)
  - gravity vector 1/100 m/s² (see `get_gravity_vector`)
  - temperature in 1 °C (see `get_temperature`)
  - calibration status (see below)

  The calibration status consists of four pairs of two bits. Each pair of bits represents the status of the current calibration.

  - bit 0-1: Magnetometer
  - bit 2-3: Accelerometer
  - bit 4-5: Gyroscope
  - bit 6-7: System

  A value of 0 means for "not calibrated" and a value of 3 means "fully calibrated". In your program you should always be able to ignore the calibration status, it is used by the calibration window of the Brick Viewer and it can be ignored after the first calibration. See the documentation in the calibration window for more information regarding the calibration of the IMU Brick.

  If you want to get the data periodically, it is recommended to use the callback `CALLBACK_ALL_DATA` and set the period with `set_all_data_period`.

`BrickIMUV2.``leds_on`

  Function ID: | 10
  Request: | empty payload
  Response: | no response

  Turns the orientation and direction LEDs of the IMU Brick on.

`BrickIMUV2.``leds_off`

  Function ID: | 11
  Request: | empty payload
  Response: | no response

  Turns the orientation and direction LEDs of the IMU Brick off.

`BrickIMUV2.``are_leds_on`

  Function ID: | 12
  Request: | empty payload

  Response:

  - leds -- bool

  Returns true if the orientation and direction LEDs of the IMU Brick are on, false otherwise.

### Advanced Functions

`BrickIMUV2.``get_acceleration`

  Function ID: | 1
  Request: | empty payload

  Response:

  - x -- int16
  - y -- int16
  - z -- int16

  Returns the calibrated acceleration from the accelerometer for the x, y and z axis in 1/100 m/s².

  If you want to get the acceleration periodically, it is recommended to use the callback `CALLBACK_ACCELERATION` and set the period with `set_acceleration_period`.

`BrickIMUV2.``get_magnetic_field`

  Function ID: | 2
  Request: | empty payload

  Response:

  - x -- int16
  - y -- int16
  - z -- int16

  Returns the calibrated magnetic field from the magnetometer for the x, y and z axis in 1/16 µT (Microtesla).

  If you want to get the magnetic field periodically, it is recommended to use the callback `CALLBACK_MAGNETIC_FIELD` and set the period with `set_magnetic_field_period`.

`BrickIMUV2.``get_angular_velocity`

  Function ID: | 3
  Request: | empty payload

  Response:

  - x -- int16
  - y -- int16
  - z -- int16

  Returns the calibrated angular velocity from the gyroscope for the x, y and z axis in 1/16 °/s.

  If you want to get the angular velocity periodically, it is recommended to use the callback `CALLBACK_ANGULAR_VELOCITY` and set the period with `set_angular_velocity_period`.

`BrickIMUV2.``get_temperature`

  Function ID: | 4
  Request: | empty payload

  Response:

  - temperature -- int8

  Returns the temperature of the IMU Brick. The temperature is given in °C. The temperature is measured in the core of the BNO055 IC, it is not the ambient temperature

`BrickIMUV2.``save_calibration`

  Function ID: | 13
  Request: | empty payload

  Response:

  - calibration_done -- bool

  A call of this function saves the current calibration to be used as a starting point for the next restart of continuous calibration of the IMU Brick.

  A return value of true means that the calibration could be used and false means that it could not be used (this happens if the calibration status is not "fully calibrated").

  This function is used by the calibration window of the Brick Viewer, you should not need to call it in your program.

`BrickIMUV2.``enable_status_led`

  Function ID: | 238
  Request: | empty payload
  Response: | no response

  Enables the status LED.

  The status LED is the blue LED next to the USB connector. If enabled is is on and it flickers if data is transfered. If disabled it is always off.

  The default state is enabled.

`BrickIMUV2.``disable_status_led`

  Function ID: | 239
  Request: | empty payload
  Response: | no response

  Disables the status LED.

  The status LED is the blue LED next to the USB connector. If enabled is is on and it flickers if data is transfered. If disabled it is always off.

  The default state is enabled.

`BrickIMUV2.``is_status_led_enabled`

  Function ID: | 240
  Request: | empty payload

  Response:

  - enabled -- bool

  Returns true if the status LED is enabled, false otherwise.

`BrickIMUV2.``get_protocol1_bricklet_name`

  Function ID: | 241

  Request:

  - port -- char

  Response:

  - protocol_version -- uint8
  - firmware_version -- uint8[3]
  - name -- char[40]

  Returns the firmware and protocol version and the name of the Bricklet for a given port.

  This functions sole purpose is to allow automatic flashing of v1.x.y Bricklet plugins.

`BrickIMUV2.``get_chip_temperature`

  Function ID: | 242
  Request: | empty payload

  Response:

  - temperature -- int16

  Returns the temperature in °C/10 as measured inside the microcontroller. The value returned is not the ambient temperature!

  The temperature is only proportional to the real temperature and it has an accuracy of +-15%. Practically it is only useful as an indicator for temperature changes.

`BrickIMUV2.``reset`

  Function ID: | 243
  Request: | empty payload
  Response: | no response

  Calling this function will reset the Brick. Calling this function on a Brick inside of a stack will reset the whole stack.

  After a reset you have to create new device objects, calling functions on the existing ones will result in undefined behavior!

`BrickIMUV2.``get_identity`

  Function ID: | 255
  Request: | empty payload

  Response:

  - uid -- char[8]
  - connected_uid -- char[8]
  - position -- char
  - hardware_version -- uint8[3]
  - firmware_version -- uint8[3]
  - device_identifier -- uint16

  Returns the UID, the UID where the Brick is connected to, the position, the hardware and firmware version as well as the device identifier.

  The position can be '0'-'8' (stack position).

  The device identifier numbers can be found here.

### Callback Configuration Functions

`BrickIMUV2.``set_acceleration_period`

  Function ID: | 14

  Request:

  - period -- uint32

  Response: | no response

  Sets the period in ms with which the `CALLBACK_ACCELERATION` callback is triggered periodically. A value of 0 turns the callback off.

  The default value is 0.

`BrickIMUV2.``get_acceleration_period`

  Function ID: | 15
  Request: | empty payload

  Response:

  - period -- uint32

  Returns the period as set by `set_acceleration_period`.

`BrickIMUV2.``set_magnetic_field_period`

  Function ID: | 16

  Request:

  - period -- uint32

  Response: | no response

  Sets the period in ms with which the `CALLBACK_MAGNETIC_FIELD` callback is triggered periodically. A value of 0 turns the callback off.

`BrickIMUV2.``get_magnetic_field_period`

  Function ID: | 17
  Request: | empty payload

  Response:

  - period -- uint32

  Returns the period as set by `set_magnetic_field_period`.

`BrickIMUV2.``set_angular_velocity_period`

  Function ID: | 18

  Request:

  - period -- uint32

  Response: | no response

  Sets the period in ms with which the `CALLBACK_ANGULAR_VELOCITY` callback is triggered periodically. A value of 0 turns the callback off.

`BrickIMUV2.``get_angular_velocity_period`

  Function ID: | 19
  Request: | empty payload

  Response:

  - period -- uint32

  Returns the period as set by `set_angular_velocity_period`.

`BrickIMUV2.``set_temperature_period`

  Function ID: | 20

  Request:

  - period -- uint32

  Response: | no response

  Sets the period in ms with which the `CALLBACK_TEMPERATURE` callback is triggered periodically. A value of 0 turns the callback off.

`BrickIMUV2.``get_temperature_period`

  Function ID: | 21
  Request: | empty payload

  Response:

  - period -- uint32

  Returns the period as set by `set_temperature_period`.

`BrickIMUV2.``set_orientation_period`

  Function ID: | 22

  Request:

  - period -- uint32

  Response: | no response

  Sets the period in ms with which the `CALLBACK_ORIENTATION` callback is triggered periodically. A value of 0 turns the callback off.

`BrickIMUV2.``get_orientation_period`

  Function ID: | 23
  Request: | empty payload

  Response:

  - period -- uint32

  Returns the period as set by `set_orientation_period`.

`BrickIMUV2.``set_linear_acceleration_period`

  Function ID: | 24

  Request:

  - period -- uint32

  Response: | no response

  Sets the period in ms with which the `CALLBACK_LINEAR_ACCELERATION` callback is triggered periodically. A value of 0 turns the callback off.

`BrickIMUV2.``get_linear_acceleration_period`

  Function ID: | 25
  Request: | empty payload

  Response:

  - period -- uint32

  Returns the period as set by `set_linear_acceleration_period`.

`BrickIMUV2.``set_gravity_vector_period`

  Function ID: | 26

  Request:

  - period -- uint32

  Response: | no response

  Sets the period in ms with which the `CALLBACK_GRAVITY_VECTOR` callback is triggered periodically. A value of 0 turns the callback off.

`BrickIMUV2.``get_gravity_vector_period`

  Function ID: | 27
  Request: | empty payload

  Response:

  - period -- uint32

  Returns the period as set by `set_gravity_vector_period`.

`BrickIMUV2.``set_quaternion_period`

  Function ID: | 28

  Request:

  - period -- uint32

  Response: | no response

  Sets the period in ms with which the `CALLBACK_QUATERNION` callback is triggered periodically. A value of 0 turns the callback off.

`BrickIMUV2.``get_quaternion_period`

  Function ID: | 29
  Request: | empty payload

  Response:

  - period -- uint32

  Returns the period as set by `set_quaternion_period`.

`BrickIMUV2.``set_all_data_period`

  Function ID: | 30

  Request:

  - period -- uint32

  Response: | no response

  Sets the period in ms with which the `CALLBACK_ALL_DATA` callback is triggered periodically. A value of 0 turns the callback off.

`BrickIMUV2.``get_all_data_period`

  Function ID: | 31
  Request: | empty payload

  Response:

  - period -- uint32

  Returns the period as set by `set_all_data_period`.

### Callbacks

`BrickIMUV2.``CALLBACK_ACCELERATION`

  Function ID: | 32

  Response:

  - x -- int16
  - y -- int16
  - z -- int16

  This callback is triggered periodically with the period that is set by `set_acceleration_period`. The response values are the acceleration for the x, y and z axis.

`BrickIMUV2.``CALLBACK_MAGNETIC_FIELD`

  Function ID: | 33

  Response:

  - x -- int16
  - y -- int16
  - z -- int16

  This callback is triggered periodically with the period that is set by `set_magnetic_field_period`. The response values are the magnetic field for the x, y and z axis.

`BrickIMUV2.``CALLBACK_ANGULAR_VELOCITY`

  Function ID: | 34

  Response:

  - x -- int16
  - y -- int16
  - z -- int16

  This callback is triggered periodically with the period that is set by `set_angular_velocity_period`. The response values are the angular velocity for the x, y and z axis.

`BrickIMUV2.``CALLBACK_TEMPERATURE`

  Function ID: | 35

  Response:

  - temperature -- int8

  This callback is triggered periodically with the period that is set by `set_temperature_period`. The response value is the temperature.

`BrickIMUV2.``CALLBACK_LINEAR_ACCELERATION`

  Function ID: | 36

  Response:

  - x -- int16
  - y -- int16
  - z -- int16

  This callback is triggered periodically with the period that is set by `set_linear_acceleration_period`. The response values are the linear acceleration for the x, y and z axis.

`BrickIMUV2.``CALLBACK_GRAVITY_VECTOR`

  Function ID: | 37

  Response:

  - x -- int16
  - y -- int16
  - z -- int16

  This callback is triggered periodically with the period that is set by `set_gravity_vector_period`. The response values gravity vector for the x, y and z axis.

`BrickIMUV2.``CALLBACK_ORIENTATION`

  Function ID: | 38

  Response:

  - heading -- int16
  - roll -- int16
  - pitch -- int16

  This callback is triggered periodically with the period that is set by `set_orientation_period`. The response values are the orientation (heading (yaw), roll, pitch) of the IMU Brick in Euler angles. See `get_orientation` for details.

`BrickIMUV2.``CALLBACK_QUATERNION`

  Function ID: | 39

  Response:

  - w -- int16
  - x -- int16
  - y -- int16
  - z -- int16

  This callback is triggered periodically with the period that is set by `set_quaternion_period`. The response values are the orientation (x, y, z, w) of the IMU Brick in quaternions. See `get_quaternion` for details.

`BrickIMUV2.``CALLBACK_ALL_DATA`

  Function ID: | 40

  Response:

  - acceleration -- int16[3]
  - magnetic_field -- int16[3]
  - angular_velocity -- int16[3]
  - euler_angle -- int16[3]
  - quaternion -- int16[4]
  - linear_acceleration -- int16[3]
  - gravity_vector -- int16[3]
  - temperature -- int8
  - calibration_status -- uint8

  This callback is triggered periodically with the period that is set by `set_all_data_period`. The response values are as for `get_all_data`.

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