Modbus - Particulate Matter Bricklet

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

API

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

Basic Functions

BrickletParticulateMatter.get_pm_concentration
Function ID:

1

Request:

empty payload

Response:
  • pm10 -- uint16
  • pm25 -- uint16
  • pm100 -- uint16

Returns the particulate matter concentration in µg/m³, broken down as:

  • PM1.0,
  • PM2.5 and
  • PM10.0.

If the sensor is disabled (see set_enable) then the last known good values from the sensor are returned.

BrickletParticulateMatter.get_pm_count
Function ID:

2

Request:

empty payload

Response:
  • greater03um -- uint16
  • greater05um -- uint16
  • greater10um -- uint16
  • greater25um -- uint16
  • greater50um -- uint16
  • greater100um -- uint16

Returns the number of particulates in 100 ml of air, broken down by their diameter:

  • greater 0.3µm,
  • greater 0.5µm,
  • greater 1.0µm,
  • greater 2.5µm,
  • greater 5.0µm and
  • greater 10.0µm.

If the sensor is disabled (see set_enable) then the last known good value from the sensor is returned.

Advanced Functions

BrickletParticulateMatter.set_enable
Function ID:

3

Request:
  • enable -- bool
Response:

no response

Enables/Disables the fan and the laser diode of the sensors. The sensor is enabled by default.

The sensor takes about 30 seconds after it is enabled to settle and produce stable values.

The laser diode has a lifetime of about 8000 hours. If you want to measure in an interval with a long idle time (e.g. hourly) you should turn the laser diode off between the measurements.

BrickletParticulateMatter.get_enable
Function ID:

4

Request:

empty payload

Response:
  • enable -- bool

Returns the state of the sensor as set by set_enable.

BrickletParticulateMatter.get_sensor_info
Function ID:

5

Request:

empty payload

Response:
  • sensor_version -- uint8
  • last_error_code -- uint8
  • framing_error_count -- uint8
  • checksum_error_count -- uint8

Returns information about the sensor:

  • the sensor version number,
  • the last error code reported by the sensor (0 means no error) and
  • the number of framing and checksum errors that occurred in the communication with the sensor.
BrickletParticulateMatter.get_spitfp_error_count
Function ID:

234

Request:

empty payload

Response:
  • error_count_ack_checksum -- uint32
  • error_count_message_checksum -- uint32
  • error_count_frame -- uint32
  • error_count_overflow -- uint32

Returns the error count for the communication between Brick and Bricklet.

The errors are divided into

  • ACK checksum errors,
  • message checksum errors,
  • framing errors and
  • overflow errors.

The errors counts are for errors that occur on the Bricklet side. All Bricks have a similar function that returns the errors on the Brick side.

BrickletParticulateMatter.set_bootloader_mode
Function ID:

235

Request:
  • mode -- uint8
Response:
  • status -- uint8

Sets the bootloader mode and returns the status after the requested mode change was instigated.

You can change from bootloader mode to firmware mode and vice versa. A change from bootloader mode to firmware mode will only take place if the entry function, device identifier and CRC are present and correct.

This function is used by Brick Viewer during flashing. It should not be necessary to call it in a normal user program.

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

  • 0: bootloader, for mode
  • 1: firmware, for mode
  • 2: bootloader wait for reboot, for mode
  • 3: firmware wait for reboot, for mode
  • 4: firmware wait for erase and reboot, for mode
  • 0: ok, for status
  • 1: invalid mode, for status
  • 2: no change, for status
  • 3: entry function not present, for status
  • 4: device identifier incorrect, for status
  • 5: crc mismatch, for status
BrickletParticulateMatter.get_bootloader_mode
Function ID:

236

Request:

empty payload

Response:
  • mode -- uint8

Returns the current bootloader mode, see set_bootloader_mode.

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

  • 0: bootloader, for mode
  • 1: firmware, for mode
  • 2: bootloader wait for reboot, for mode
  • 3: firmware wait for reboot, for mode
  • 4: firmware wait for erase and reboot, for mode
BrickletParticulateMatter.set_write_firmware_pointer
Function ID:

237

Request:
  • pointer -- uint32
Response:

no response

Sets the firmware pointer for write_firmware. The pointer has to be increased by chunks of size 64. The data is written to flash every 4 chunks (which equals to one page of size 256).

This function is used by Brick Viewer during flashing. It should not be necessary to call it in a normal user program.

BrickletParticulateMatter.write_firmware
Function ID:

238

Request:
  • data -- uint8[64]
Response:
  • status -- uint8

Writes 64 Bytes of firmware at the position as written by set_write_firmware_pointer before. The firmware is written to flash every 4 chunks.

You can only write firmware in bootloader mode.

This function is used by Brick Viewer during flashing. It should not be necessary to call it in a normal user program.

BrickletParticulateMatter.set_status_led_config
Function ID:

239

Request:
  • config -- uint8
Response:

no response

Sets the status LED configuration. By default the LED shows communication traffic between Brick and Bricklet, it flickers once for every 10 received data packets.

You can also turn the LED permanently on/off or show a heartbeat.

If the Bricklet is in bootloader mode, the LED is will show heartbeat by default.

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

  • 0: off, for config
  • 1: on, for config
  • 2: show heartbeat, for config
  • 3: show status, for config
BrickletParticulateMatter.get_status_led_config
Function ID:

240

Request:

empty payload

Response:
  • config -- uint8

Returns the configuration as set by set_status_led_config

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

  • 0: off, for config
  • 1: on, for config
  • 2: show heartbeat, for config
  • 3: show status, for config
BrickletParticulateMatter.get_chip_temperature
Function ID:

242

Request:

empty payload

Response:
  • temperature -- int16

Returns the temperature in °C as measured inside the microcontroller. The value returned is not the ambient temperature!

The temperature is only proportional to the real temperature and it has bad accuracy. Practically it is only useful as an indicator for temperature changes.

BrickletParticulateMatter.reset
Function ID:243
Request:empty payload
Response:no response

Calling this function will reset the Bricklet. All configurations will be lost.

After a reset you have to create new device objects, calling functions on the existing ones will result in undefined behavior!

BrickletParticulateMatter.write_uid
Function ID:

248

Request:
  • uid -- uint32
Response:

no response

Writes a new UID into flash. If you want to set a new UID you have to decode the Base58 encoded UID string into an integer first.

We recommend that you use Brick Viewer to change the UID.

BrickletParticulateMatter.read_uid
Function ID:

249

Request:

empty payload

Response:
  • uid -- uint32

Returns the current UID as an integer. Encode as Base58 to get the usual string version.

BrickletParticulateMatter.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

BrickletParticulateMatter.set_pm_concentration_callback_configuration
Function ID:

6

Request:
  • period -- uint32
  • value_has_to_change -- bool
Response:

no response

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

If the value has to change-parameter is set to true, the callback is only triggered after the value has changed. If the value didn't change within the period, the callback is triggered immediately on change.

If it is set to false, the callback is continuously triggered with the period, independent of the value.

The default value is (0, false).

BrickletParticulateMatter.get_pm_concentration_callback_configuration
Function ID:

7

Request:

empty payload

Response:
  • period -- uint32
  • value_has_to_change -- bool

Returns the callback configuration as set by set_pm_concentration_callback_configuration.

BrickletParticulateMatter.set_pm_count_callback_configuration
Function ID:

8

Request:
  • period -- uint32
  • value_has_to_change -- bool
Response:

no response

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

If the value has to change-parameter is set to true, the callback is only triggered after the value has changed. If the value didn't change within the period, the callback is triggered immediately on change.

If it is set to false, the callback is continuously triggered with the period, independent of the value.

The default value is (0, false).

BrickletParticulateMatter.get_pm_count_callback_configuration
Function ID:

9

Request:

empty payload

Response:
  • period -- uint32
  • value_has_to_change -- bool

Returns the callback configuration as set by set_pm_count_callback_configuration.

Callbacks

BrickletParticulateMatter.CALLBACK_PM_CONCENTRATION
Function ID:

10

Response:
  • pm10 -- uint16
  • pm25 -- uint16
  • pm100 -- uint16

This callback is triggered periodically according to the configuration set by set_pm_concentration_callback_configuration.

The response values are the same as get_pm_concentration.

BrickletParticulateMatter.CALLBACK_PM_COUNT
Function ID:

11

Response:
  • greater03um -- uint16
  • greater05um -- uint16
  • greater10um -- uint16
  • greater25um -- uint16
  • greater50um -- uint16
  • greater100um -- uint16

This callback is triggered periodically according to the configuration set by set_pm_count_callback_configuration.

The response values are the same as get_pm_count.