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Specifications / Modbus Protocol / API / Bricklets (Discontinued) / CO2 Bricklet

Modbus - CO2 Bricklet

This is the description of the Modbus protocol for the CO2 Bricklet. General information and technical specifications for the CO2 Bricklet are summarized in its hardware description.

API

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

Basic Functions

BrickletCO2.get_co2_concentration
Function ID:
  • 1
Request:
  • empty payload
Response:
  • co2_concentration – Type: uint16, Unit: 1 ppm, Range: [0 to 10000]

Returns the measured CO2 concentration.

If you want to get the CO2 concentration periodically, it is recommended to use the CALLBACK_CO2_CONCENTRATION callback and set the period with set_co2_concentration_callback_period.

Advanced Functions

BrickletCO2.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', '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). A Bricklet connected to an Isolator Bricklet is always at position 'z'.

The device identifier numbers can be found here. 

Callback Configuration Functions

BrickletCO2.set_co2_concentration_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_CO2_CONCENTRATION callback is triggered periodically. A value of 0 turns the callback off.

The CALLBACK_CO2_CONCENTRATION callback is only triggered if the CO2 concentration has changed since the last triggering.

BrickletCO2.get_co2_concentration_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_co2_concentration_callback_period.

BrickletCO2.set_co2_concentration_callback_threshold
Function ID:
  • 4
Request:
  • option – Type: char, Range: See meanings, Default: 'x'
  • min – Type: uint16, Unit: 1 ppm, Range: [0 to 216 - 1], Default: 0
  • max – Type: uint16, Unit: 1 ppm, Range: [0 to 216 - 1], Default: 0
Response:
  • no response

Sets the thresholds for the CALLBACK_CO2_CONCENTRATION_REACHED callback.

The following options are possible:

Option Description
'x' Callback is turned off
'o' Callback is triggered when the CO2 concentration is outside the min and max values
'i' Callback is triggered when the CO2 concentration is inside the min and max values
'<' Callback is triggered when the CO2 concentration is smaller than the min value (max is ignored)
'>' Callback is triggered when the CO2 concentration 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
BrickletCO2.get_co2_concentration_callback_threshold
Function ID:
  • 5
Request:
  • empty payload
Response:
  • option – Type: char, Range: See meanings, Default: 'x'
  • min – Type: uint16, Unit: 1 ppm, Range: [0 to 216 - 1], Default: 0
  • max – Type: uint16, Unit: 1 ppm, Range: [0 to 216 - 1], Default: 0

Returns the threshold as set by set_co2_concentration_callback_threshold.

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

For option:

  • 'x' = Off
  • 'o' = Outside
  • 'i' = Inside
  • '<' = Smaller
  • '>' = Greater
BrickletCO2.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.

BrickletCO2.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

BrickletCO2.CALLBACK_CO2_CONCENTRATION
Function ID:
  • 8
Response:
  • co2_concentration – Type: uint16, Unit: 1 ppm, Range: [0 to 10000]

This callback is triggered periodically with the period that is set by set_co2_concentration_callback_period. The response value is the CO2 concentration of the sensor.

The CALLBACK_CO2_CONCENTRATION callback is only triggered if the CO2 concentration has changed since the last triggering.

BrickletCO2.CALLBACK_CO2_CONCENTRATION_REACHED
Function ID:
  • 9
Response:
  • co2_concentration – Type: uint16, Unit: 1 ppm, Range: [0 to 10000]

This callback is triggered when the threshold as set by set_co2_concentration_callback_threshold is reached. The response value is the CO2 concentration.

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