Modbus - Ambient Light Bricklet 2.0

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

API

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

Basic Functions

BrickletAmbientLightV2.get_illuminance
Function ID:

1

Request:

empty payload

Response:
  • illuminance -- uint32

Returns the illuminance of the ambient light sensor. The measurement range goes up to about 100000lux, but above 64000lux the precision starts to drop. The illuminance is given in lux/100, i.e. a value of 450000 means that an illuminance of 4500lux is measured.

Changed in version 2.0.2 (Plugin): An illuminance of 0lux indicates that the sensor is saturated and the configuration should be modified, see set_configuration.

If you want to get the illuminance periodically, it is recommended to use the CALLBACK_ILLUMINANCE callback and set the period with set_illuminance_callback_period.

Advanced Functions

BrickletAmbientLightV2.set_configuration
Function ID:

8

Request:
  • illuminance_range -- uint8
  • integration_time -- uint8
Response:

no response

Sets the configuration. It is possible to configure an illuminance range between 0-600lux and 0-64000lux and an integration time between 50ms and 400ms.

New in version 2.0.2 (Plugin): The unlimited illuminance range allows to measure up to about 100000lux, but above 64000lux the precision starts to drop.

A smaller illuminance range increases the resolution of the data. A longer integration time will result in less noise on the data.

Changed in version 2.0.2 (Plugin): If the actual measure illuminance is out-of-range then the current illuminance range maximum +0.01lux is reported by get_illuminance and the CALLBACK_ILLUMINANCE callback. For example, 800001 for the 0-8000lux range.

Changed in version 2.0.2 (Plugin): With a long integration time the sensor might be saturated before the measured value reaches the maximum of the selected illuminance range. In this case 0lux is reported by get_illuminance and the CALLBACK_ILLUMINANCE callback.

If the measurement is out-of-range or the sensor is saturated then you should configure the next higher illuminance range. If the highest range is already in use, then start to reduce the integration time.

The default values are 0-8000lux illuminance range and 200ms integration time.

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

  • 6: unlimited, for illuminance_range
  • 0: 64000lux, for illuminance_range
  • 1: 32000lux, for illuminance_range
  • 2: 16000lux, for illuminance_range
  • 3: 8000lux, for illuminance_range
  • 4: 1300lux, for illuminance_range
  • 5: 600lux, for illuminance_range
  • 0: 50ms, for integration_time
  • 1: 100ms, for integration_time
  • 2: 150ms, for integration_time
  • 3: 200ms, for integration_time
  • 4: 250ms, for integration_time
  • 5: 300ms, for integration_time
  • 6: 350ms, for integration_time
  • 7: 400ms, for integration_time
BrickletAmbientLightV2.get_configuration
Function ID:

9

Request:

empty payload

Response:
  • illuminance_range -- uint8
  • integration_time -- uint8

Returns the configuration as set by set_configuration.

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

  • 6: unlimited, for illuminance_range
  • 0: 64000lux, for illuminance_range
  • 1: 32000lux, for illuminance_range
  • 2: 16000lux, for illuminance_range
  • 3: 8000lux, for illuminance_range
  • 4: 1300lux, for illuminance_range
  • 5: 600lux, for illuminance_range
  • 0: 50ms, for integration_time
  • 1: 100ms, for integration_time
  • 2: 150ms, for integration_time
  • 3: 200ms, for integration_time
  • 4: 250ms, for integration_time
  • 5: 300ms, for integration_time
  • 6: 350ms, for integration_time
  • 7: 400ms, for integration_time
BrickletAmbientLightV2.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

BrickletAmbientLightV2.set_illuminance_callback_period
Function ID:

2

Request:
  • period -- uint32
Response:

no response

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

The CALLBACK_ILLUMINANCE callback is only triggered if the illuminance has changed since the last triggering.

The default value is 0.

BrickletAmbientLightV2.get_illuminance_callback_period
Function ID:

3

Request:

empty payload

Response:
  • period -- uint32

Returns the period as set by set_illuminance_callback_period.

BrickletAmbientLightV2.set_illuminance_callback_threshold
Function ID:

4

Request:
  • option -- char
  • min -- uint32
  • max -- uint32
Response:

no response

Sets the thresholds for the CALLBACK_ILLUMINANCE_REACHED callback.

The following options are possible:

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

The default value is ('x', 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
BrickletAmbientLightV2.get_illuminance_callback_threshold
Function ID:

5

Request:

empty payload

Response:
  • option -- char
  • min -- uint32
  • max -- uint32

Returns the threshold as set by set_illuminance_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
BrickletAmbientLightV2.set_debounce_period
Function ID:

6

Request:
  • debounce -- uint32
Response:

no response

Sets the period in ms with which the threshold callbacks

are triggered, if the thresholds

keep being reached.

The default value is 100.

BrickletAmbientLightV2.get_debounce_period
Function ID:

7

Request:

empty payload

Response:
  • debounce -- uint32

Returns the debounce period as set by set_debounce_period.

Callbacks

BrickletAmbientLightV2.CALLBACK_ILLUMINANCE
Function ID:

10

Response:
  • illuminance -- uint32

This callback is triggered periodically with the period that is set by set_illuminance_callback_period. The response value is the illuminance of the ambient light sensor.

The CALLBACK_ILLUMINANCE callback is only triggered if the illuminance has changed since the last triggering.

BrickletAmbientLightV2.CALLBACK_ILLUMINANCE_REACHED
Function ID:

11

Response:
  • illuminance -- uint32

This callback is triggered when the threshold as set by set_illuminance_callback_threshold is reached. The response value is the illuminance of the ambient light sensor.

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