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 – Type: uint32, Unit: 1/100 lx, Range: [0 to 232 - 1]

Returns the illuminance of the ambient light sensor. The measurement range goes up to about 100000lux, but above 64000lux the precision starts to drop.

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 – Type: uint8, Range: See meanings, Default: 3
  • integration_time – Type: uint8, Range: See meanings, Default: 3
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 following meanings are defined for the elements of this function:

For illuminance_range:

  • 6 = Unlimited
  • 0 = 64000Lux
  • 1 = 32000Lux
  • 2 = 16000Lux
  • 3 = 8000Lux
  • 4 = 1300Lux
  • 5 = 600Lux

For integration_time:

  • 0 = 50ms
  • 1 = 100ms
  • 2 = 150ms
  • 3 = 200ms
  • 4 = 250ms
  • 5 = 300ms
  • 6 = 350ms
  • 7 = 400ms
BrickletAmbientLightV2.get_configuration
Function ID:
  • 9
Request:
  • empty payload
Response:
  • illuminance_range – Type: uint8, Range: See meanings, Default: 3
  • integration_time – Type: uint8, Range: See meanings, Default: 3

Returns the configuration as set by set_configuration.

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

For illuminance_range:

  • 6 = Unlimited
  • 0 = 64000Lux
  • 1 = 32000Lux
  • 2 = 16000Lux
  • 3 = 8000Lux
  • 4 = 1300Lux
  • 5 = 600Lux

For integration_time:

  • 0 = 50ms
  • 1 = 100ms
  • 2 = 150ms
  • 3 = 200ms
  • 4 = 250ms
  • 5 = 300ms
  • 6 = 350ms
  • 7 = 400ms
BrickletAmbientLightV2.get_identity
Function ID:
  • 255
Request:
  • empty payload
Response:
  • uid – Type: char[8]
  • connected_uid – Type: char[8]
  • position – Type: char, Range: ['a' to 'h', 'i', 'z']
  • hardware_version – Type: uint8[3]
    • 0: major – Type: uint8, Range: [0 to 255]
    • 1: minor – Type: uint8, Range: [0 to 255]
    • 2: revision – Type: uint8, Range: [0 to 255]
  • firmware_version – Type: uint8[3]
    • 0: major – Type: uint8, Range: [0 to 255]
    • 1: minor – Type: uint8, Range: [0 to 255]
    • 2: revision – Type: uint8, Range: [0 to 255]
  • device_identifier – Type: uint16, Range: [0 to 216 - 1]

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', 'd', 'e', 'f', 'g' or 'h' (Bricklet Port). The Raspberry Pi HAT (Zero) Brick is always at position 'i' and the Bricklet connected to an Isolator Bricklet is always as position 'z'.

The device identifier numbers can be found here

Callback Configuration Functions

BrickletAmbientLightV2.set_illuminance_callback_period
Function ID:
  • 2
Request:
  • period – Type: uint32, Unit: 1 ms, Range: [0 to 232 - 1], Default: 0
Response:
  • no response

Sets the period 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.

BrickletAmbientLightV2.get_illuminance_callback_period
Function ID:
  • 3
Request:
  • empty payload
Response:
  • period – Type: uint32, Unit: 1 ms, Range: [0 to 232 - 1], Default: 0

Returns the period as set by set_illuminance_callback_period.

BrickletAmbientLightV2.set_illuminance_callback_threshold
Function ID:
  • 4
Request:
  • option – Type: char, Range: See meanings, Default: 'x'
  • min – Type: uint32, Unit: 1/100 lx, Range: [0 to 232 - 1], Default: 0
  • max – Type: uint32, Unit: 1/100 lx, Range: [0 to 232 - 1], Default: 0
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 following meanings are defined for the elements of this function:

For option:

  • 'x' = Off
  • 'o' = Outside
  • 'i' = Inside
  • '<' = Smaller
  • '>' = Greater
BrickletAmbientLightV2.get_illuminance_callback_threshold
Function ID:
  • 5
Request:
  • empty payload
Response:
  • option – Type: char, Range: See meanings, Default: 'x'
  • min – Type: uint32, Unit: 1/100 lx, Range: [0 to 232 - 1], Default: 0
  • max – Type: uint32, Unit: 1/100 lx, Range: [0 to 232 - 1], Default: 0

Returns the threshold as set by set_illuminance_callback_threshold.

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

For option:

  • 'x' = Off
  • 'o' = Outside
  • 'i' = Inside
  • '<' = Smaller
  • '>' = Greater
BrickletAmbientLightV2.set_debounce_period
Function ID:
  • 6
Request:
  • debounce – Type: uint32, Unit: 1 ms, Range: [0 to 232 - 1], Default: 100
Response:
  • no response

Sets the period with which the threshold callbacks

are triggered, if the thresholds

keep being reached.

BrickletAmbientLightV2.get_debounce_period
Function ID:
  • 7
Request:
  • empty payload
Response:
  • debounce – Type: uint32, Unit: 1 ms, Range: [0 to 232 - 1], Default: 100

Returns the debounce period as set by set_debounce_period.

Callbacks

BrickletAmbientLightV2.CALLBACK_ILLUMINANCE
Function ID:
  • 10
Response:
  • illuminance – Type: uint32, Unit: 1/100 lx, Range: [0 to 232 - 1]

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 – Type: uint32, Unit: 1/100 lx, Range: [0 to 232 - 1]

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.