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 450lux is measured.

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

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_ANALOG_VALUE callback 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.

The CALLBACK_ILLUMINANCE callback 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.

The CALLBACK_ANALOG_VALUE callback 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 -- uint16
  • max -- uint16
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
BrickletAmbientLight.get_illuminance_callback_threshold
Function ID:

8

Request:

empty payload

Response:
  • option -- char
  • min -- uint16
  • max -- uint16

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
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).

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
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.

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
BrickletAmbientLight.set_debounce_period
Function ID:

11

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.

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.

The CALLBACK_ILLUMINANCE callback 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.

The CALLBACK_ANALOG_VALUE callback 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.