Modbus - Ambient Light Bricklet – Tinkerforge

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# Modbus - Ambient Light Bricklet

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

## API

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

### Basic Functions

`BrickletAmbientLight.``get_illuminance`

  Function ID: | 1
  Request: | empty payload

  Response:

  - illuminance -- uint16

  Returns the illuminance of the ambient light sensor. The value has a range of 0 to 9000 and is given in Lux/10, i.e. a value of 4500 means that an illuminance of 450 Lux is measured.

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

### Advanced Functions

`BrickletAmbientLight.``get_analog_value`

  Function ID: | 2
  Request: | empty payload

  Response:

  - value -- uint16

  Returns the value as read by a 12-bit analog-to-digital converter. The value is between 0 and 4095.

  Note

  The value returned by `get_illuminance` is averaged over several samples to yield less noise, while `get_analog_value` gives back raw unfiltered analog values. The only reason to use `get_analog_value` is, if you need the full resolution of the analog-to-digital converter.

  Also, the analog-to-digital converter covers three different ranges that are set dynamically depending on the light intensity. It is impossible to distinguish between these ranges with the analog value.

  If you want the analog value periodically, it is recommended to use the callback `CALLBACK_ANALOG_VALUE` and set the period with `set_analog_value_callback_period`.

`BrickletAmbientLight.``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

`BrickletAmbientLight.``set_illuminance_callback_period`

  Function ID: | 3

  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.

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

  The default value is 0.

`BrickletAmbientLight.``get_illuminance_callback_period`

  Function ID: | 4
  Request: | empty payload

  Response:

  - period -- uint32

  Returns the period as set by `set_illuminance_callback_period`.

`BrickletAmbientLight.``set_analog_value_callback_period`

  Function ID: | 5

  Request:

  - period -- uint32

  Response: | no response

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

  `CALLBACK_ANALOG_VALUE` is only triggered if the analog value has changed since the last triggering.

  The default value is 0.

`BrickletAmbientLight.``get_analog_value_callback_period`

  Function ID: | 6
  Request: | empty payload

  Response:

  - period -- uint32

  Returns the period as set by `set_analog_value_callback_period`.

`BrickletAmbientLight.``set_illuminance_callback_threshold`

  Function ID: | 7

  Request:

  - option -- char
  - min -- int16
  - max -- int16

  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).

`BrickletAmbientLight.``get_illuminance_callback_threshold`

  Function ID: | 8
  Request: | empty payload

  Response:

  - option -- char
  - min -- int16
  - max -- int16

  Returns the threshold as set by `set_illuminance_callback_threshold`.

`BrickletAmbientLight.``set_analog_value_callback_threshold`

  Function ID: | 9

  Request:

  - option -- char
  - min -- uint16
  - max -- uint16

  Response: | no response

  Sets the thresholds for the `CALLBACK_ANALOG_VALUE_REACHED` callback.

  The following options are possible:

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

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

`BrickletAmbientLight.``get_analog_value_callback_threshold`

  Function ID: | 10
  Request: | empty payload

  Response:

  - option -- char
  - min -- uint16
  - max -- uint16

  Returns the threshold as set by `set_analog_value_callback_threshold`.

`BrickletAmbientLight.``set_debounce_period`

  Function ID: | 11

  Request:

  - debounce -- uint32

  Response: | no response

  Sets the period in ms with which the threshold callbacks

  - `CALLBACK_ILLUMINANCE_REACHED`,
  - `CALLBACK_ANALOG_VALUE_REACHED`

  are triggered, if the thresholds

  - `set_illuminance_callback_threshold`,
  - `set_analog_value_callback_threshold`

  keep being reached.

  The default value is 100.

`BrickletAmbientLight.``get_debounce_period`

  Function ID: | 12
  Request: | empty payload

  Response:

  - debounce -- uint32

  Returns the debounce period as set by `set_debounce_period`.

### Callbacks

`BrickletAmbientLight.``CALLBACK_ILLUMINANCE`

  Function ID: | 13

  Response:

  - illuminance -- uint16

  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.

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

`BrickletAmbientLight.``CALLBACK_ANALOG_VALUE`

  Function ID: | 14

  Response:

  - value -- uint16

  This callback is triggered periodically with the period that is set by `set_analog_value_callback_period`. The response value is the analog value of the ambient light sensor.

  `CALLBACK_ANALOG_VALUE` is only triggered if the analog value has changed since the last triggering.

`BrickletAmbientLight.``CALLBACK_ILLUMINANCE_REACHED`

  Function ID: | 15

  Response:

  - illuminance -- uint16

  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`.

`BrickletAmbientLight.``CALLBACK_ANALOG_VALUE_REACHED`

  Function ID: | 16

  Response:

  - value -- uint16

  This callback is triggered when the threshold as set by `set_analog_value_callback_threshold` is reached. The response value is the analog value 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`.

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