Modbus - Accelerometer Bricklet

This is the description of the Modbus protocol for the Accelerometer Bricklet. General information and technical specifications for the Accelerometer Bricklet are summarized in its hardware description.

API

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

Basic Functions

BrickletAccelerometer.get_acceleration
Function ID:

1

Request:

empty payload

Response:
  • x -- int16
  • y -- int16
  • z -- int16

Returns the acceleration in x, y and z direction. The values are given in g/1000 (1g = 9.80665m/s²), not to be confused with grams.

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

BrickletAccelerometer.get_temperature
Function ID:

8

Request:

empty payload

Response:
  • temperature -- int16

Returns the temperature of the accelerometer in °C.

BrickletAccelerometer.led_on
Function ID:11
Request:empty payload
Response:no response

Enables the LED on the Bricklet.

BrickletAccelerometer.led_off
Function ID:12
Request:empty payload
Response:no response

Disables the LED on the Bricklet.

BrickletAccelerometer.is_led_on
Function ID:

13

Request:

empty payload

Response:
  • on -- bool

Returns true if the LED is enabled, false otherwise.

Advanced Functions

BrickletAccelerometer.set_configuration
Function ID:

9

Request:
  • data_rate -- uint8
  • full_scale -- uint8
  • filter_bandwidth -- uint8
Response:

no response

Configures the data rate, full scale range and filter bandwidth. Possible values are:

  • Data rate of 0Hz to 1600Hz.
  • Full scale range of -2G to +2G up to -16G to +16G.
  • Filter bandwidth between 50Hz and 800Hz.

Decreasing data rate or full scale range will also decrease the noise on the data.

The default values are 100Hz data rate, -4G to +4G range and 200Hz filter bandwidth.

The following meanings are defined for the parameters of this function:

  • 0: off, for data_rate
  • 1: 3hz, for data_rate
  • 2: 6hz, for data_rate
  • 3: 12hz, for data_rate
  • 4: 25hz, for data_rate
  • 5: 50hz, for data_rate
  • 6: 100hz, for data_rate
  • 7: 400hz, for data_rate
  • 8: 800hz, for data_rate
  • 9: 1600hz, for data_rate
  • 0: 2g, for full_scale
  • 1: 4g, for full_scale
  • 2: 6g, for full_scale
  • 3: 8g, for full_scale
  • 4: 16g, for full_scale
  • 0: 800hz, for filter_bandwidth
  • 1: 400hz, for filter_bandwidth
  • 2: 200hz, for filter_bandwidth
  • 3: 50hz, for filter_bandwidth
BrickletAccelerometer.get_configuration
Function ID:

10

Request:

empty payload

Response:
  • data_rate -- uint8
  • full_scale -- uint8
  • filter_bandwidth -- uint8

Returns the configuration as set by set_configuration.

The following meanings are defined for the parameters of this function:

  • 0: off, for data_rate
  • 1: 3hz, for data_rate
  • 2: 6hz, for data_rate
  • 3: 12hz, for data_rate
  • 4: 25hz, for data_rate
  • 5: 50hz, for data_rate
  • 6: 100hz, for data_rate
  • 7: 400hz, for data_rate
  • 8: 800hz, for data_rate
  • 9: 1600hz, for data_rate
  • 0: 2g, for full_scale
  • 1: 4g, for full_scale
  • 2: 6g, for full_scale
  • 3: 8g, for full_scale
  • 4: 16g, for full_scale
  • 0: 800hz, for filter_bandwidth
  • 1: 400hz, for filter_bandwidth
  • 2: 200hz, for filter_bandwidth
  • 3: 50hz, for filter_bandwidth
BrickletAccelerometer.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 Bricklet is connected to, the position, the hardware and firmware version as well as the device identifier.

The position can be 'a', 'b', 'c' or 'd'.

The device identifier numbers can be found here

Callback Configuration Functions

BrickletAccelerometer.set_acceleration_callback_period
Function ID:

2

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 CALLBACK_ACCELERATION callback is only triggered if the acceleration has changed since the last triggering.

The default value is 0.

BrickletAccelerometer.get_acceleration_callback_period
Function ID:

3

Request:

empty payload

Response:
  • period -- uint32

Returns the period as set by set_acceleration_callback_period.

BrickletAccelerometer.set_acceleration_callback_threshold
Function ID:

4

Request:
  • option -- char
  • min_x -- int16
  • max_x -- int16
  • min_y -- int16
  • max_y -- int16
  • min_z -- int16
  • max_z -- int16
Response:

no response

Sets the thresholds for the CALLBACK_ACCELERATION_REACHED callback.

The following options are possible:

Option Description
'x' Callback is turned off
'o' Callback is triggered when the acceleration is outside the min and max values
'i' Callback is triggered when the acceleration is inside the min and max values
'<' Callback is triggered when the acceleration is smaller than the min value (max is ignored)
'>' Callback is triggered when the acceleration is greater than the min value (max is ignored)

The default value is ('x', 0, 0, 0, 0, 0, 0).

The following meanings are defined for the parameters of this function:

  • x: off, for option
  • o: outside, for option
  • i: inside, for option
  • <: smaller, for option
  • >: greater, for option
BrickletAccelerometer.get_acceleration_callback_threshold
Function ID:

5

Request:

empty payload

Response:
  • option -- char
  • min_x -- int16
  • max_x -- int16
  • min_y -- int16
  • max_y -- int16
  • min_z -- int16
  • max_z -- int16

Returns the threshold as set by set_acceleration_callback_threshold.

The following meanings are defined for the parameters of this function:

  • x: off, for option
  • o: outside, for option
  • i: inside, for option
  • <: smaller, for option
  • >: greater, for option
BrickletAccelerometer.set_debounce_period
Function ID:

6

Request:
  • debounce -- uint32
Response:

no response

Sets the period in ms with which the threshold callback

is triggered, if the threshold

keeps being reached.

The default value is 100.

BrickletAccelerometer.get_debounce_period
Function ID:

7

Request:

empty payload

Response:
  • debounce -- uint32

Returns the debounce period as set by set_debounce_period.

Callbacks

BrickletAccelerometer.CALLBACK_ACCELERATION
Function ID:

14

Response:
  • x -- int16
  • y -- int16
  • z -- int16

This callback is triggered periodically with the period that is set by set_acceleration_callback_period. The response values are the X, Y and Z acceleration.

The CALLBACK_ACCELERATION callback is only triggered if the acceleration has changed since the last triggering.

BrickletAccelerometer.CALLBACK_ACCELERATION_REACHED
Function ID:

15

Response:
  • x -- int16
  • y -- int16
  • z -- int16

This callback is triggered when the threshold as set by set_acceleration_callback_threshold is reached. The response values are the X, Y and Z acceleration.

If the threshold keeps being reached, the callback is triggered periodically with the period as set by set_debounce_period.