SENSIRION SCD4x Manual
  1. Manuals
  2. Brands
  3. SENSIRION Manuals
  4. Accessories
  5. SCD4x
  6. Manual

SENSIRION SCD4x Manual

Breaking the size barrier in co2 sensing
Hide thumbs
Table of Contents

Advertisement

Quick Links

SCD4x
Breaking the size barrier in CO
Features
Photoacoustic sensor technology PASens®
▪
▪
Smallest form factor: 10.1 x 10.1 x 6.5 mm
Reflow solderable for cost effective assembly
▪
Large output range: 0 ppm – 40'000 ppm
▪
Large supply voltage range: 2.4 – 5.5 V
▪
Product Summary
The SCD4x is Sensirion's next generation miniature CO
sensor. This sensor builds on the photoacoustic sensing
principle and Sensirion's patented PAsens® and
CMOSens® technology to offer high accuracy at an
unmatched price and smallest form factor. SMD assembly
allows cost- and space-effective integration of the sensor
combined with maximal freedom of design. On-chip signal
compensation is realized with the build-in SHT4x humidity
and temperature sensor.
Device Overview
Products
Details
SCD40-D-R2 Base accuracy, specified range
400 – 2'000 ppm
SCD41-D-R2 High accuracy, specified range
400 – 5'000 ppm, single shot
mode supported
Full product list on page 21
www.sensirion.com
sensing
2
▪
▪
3
▪
▪
CO
2
2
compromise humans' cognitive low power
and well-being. The SCD4x enables smart ventilation
systems to regulate ventilation in the most energy-efficient
and human-friendly way. Moreover, indoor air quality
monitors and other connected devices based on the
SCD4x can help maintaining low CO
healthy, productive environment.
Functional Block Diagram
Version 1.1 – April 2021
High accuracy: ±(40 ppm + 5 %)
Digital I
C interface
2
Integrated temperature and humidity sensor
Low power operation down to < 0.4 mA avg.
@ 5 V, 1 meas. / 5 minutes
is a key indicator for indoor air quality as high levels
concentration for a
2
1/22

Advertisement

Table of Contents
loading
Need help?

Need help?

Do you have a question about the SCD4x and is the answer not in the manual?

Questions and answers

Related Manuals for SENSIRION SCD4x

Summary of Contents for SENSIRION SCD4x

  • Page 1 ▪ Product Summary is a key indicator for indoor air quality as high levels The SCD4x is Sensirion’s next generation miniature CO compromise humans’ cognitive low power sensor. This sensor builds on the photoacoustic sensing principle and Sensirion’s patented PAsens® and and well-being.

  • Page 2: Table Of Contents

    Digital Interface Description ......................... 7 Power-Up and Communication Start ......................7 Data type & length ........................... 7 Command Sequence Types ........................7 SCD4x Command Overview ........................8 Basic Commands ............................ 9 On-Chip Output Signal Compensation ....................10 Field Calibration ............................ 12 Low Power operation..........................

  • Page 3: Sensor Performance

    Design-in of the SCD4x in final application, self-heating of the sensor and the environment impacts the accuracy of the RH/T sensor. To realize indicated specifications, the temperature-offset of the SCD4x inside the customer device must be set correctly (see chapter 3.6). Best RH/T accuracy is realized when operating the SCD4x in low power periodic measurement mode.

  • Page 4: Specifications

    Accuracy can be reduced at relative humidity levels lower than 10 %. Short term storage refers to temporary conditions during e.g. transport. For proper function of ASC field-calibration algorithm the SCD4x has to be exposed to clean air with 400 ppm CO concentration regularly.

  • Page 5: Interface Specifications

    2.3 Interface Specifications The SCD4x comes in an LGA package (Table 6). The package outline is schematically displayed in chapter 4.1. The landing pattern of the SCD4x can be found in chapter 4.2. Name Comments Supply voltage Supply voltage IR source, must...

  • Page 6: Timing Specifications

    2.4 Timing Specifications Table 7 list the timings of the ASIC part and does not reflect the availability or usefulness of the sensor readings. The SCD4x supports the I C “standard-mode” as is described elsewhere (see footnote Parameter Condition Min.

  • Page 7: Digital Interface Description

    Digital Interface Description All SCD4x commands and data are mapped to a 16-bit address space. SCD4x Hex. Code C address 0x62 Table 8 I C device address. 3.1 Power-Up and Communication Start The sensor starts powering-up after reaching the power-up threshold voltage V = 2.25 V.

  • Page 8: Scd4X Command Overview

    3.4 SCD4x Command Overview Table 9: List of SCD4x sensor commands. Detailed description of SCD4x commands can be found further down. *Column indicates whether command can be executed while a periodic measurement is running. Domain Command Hex. C sequence type...

  • Page 9: Basic Commands

    3.5 Basic Commands This section lists the basic SCD4x commands that are necessary to start a periodic measurement and subsequently read out the sensor outputs. The typical communication sequence between the I C master (e.g., a microcontroller) and the SCD4x sensor is as follows: 1.

  • Page 10: On-Chip Output Signal Compensation

    Note that the temperature offset does not impact the accuracy of the CO output. To change or read sensor settings, the SCD4x must be in idle mode. A typical sequence between the I C master and the SCD4x is described as follows: 1.
  • Page 11 Description Reading and writing of the sensor altitude must be done while the SCD4x is in idle mode. Typically, the sensor altitude is set once after device installation. To save the setting to the EEPROM, the persist setting (see chapter 3.9.1) command must be issued.

  • Page 12: Field Calibration

    Automatic self-calibration (ASC) ensures highest long-term stability of the SCD4x without the need of manual action steps from the user. The automatic self- calibration algorithm assumes that the sensor is exposed to the atmospheric CO concentration of 400 ppm at least once per week.
  • Page 13 = 1 → ASC enabled word[0] = 0 → ASC disabled Example: read automatic self-calibration status: disabled Write 0x2313 (hexadecimal) Command Wait 1 ms command execution time Response 0x0000 0x81 (hexadecimal) ASC disabled CRC of 0x0000 www.sensirion.com Version 1.1 – April 2021 13/22...

  • Page 14: Low Power Operation

    3.8 Low Power operation To enable use-cases with a constrained power-budget, the SCD4x features a low power periodic measurement mode with signal update interval of approximately 30 seconds. While the low power mode saves power and reduces self-heating of the sensor, the low power periodic measurement mode has a longer response time.

  • Page 15: Advanced Features

    (RAM) only and will be lost after a power-cycle. The persist_settings command stores the current configuration in the EEPROM of the SCD4x, making them persistent across power-cycling. To avoid unnecessary wear of the EEPROM, the persist_settings command should only be sent when persistence is required and if actual changes to the configuration have been made.
  • Page 16 Description: The reinit command reinitializes the sensor by reloading user settings from EEPROM. Before sending the reinit command, the stop measurement command must be issued. If the reinit command does not trigger the desired re-initialization, a power-cycle should be applied to the SCD4x. Table 27: reinit I...

  • Page 17: Low Power Single Shot (Scd41)

    Input parameter: - Response parameter: - Write Max. command (hexadecimal) duration [ms] length [bytes] signal conversion length [bytes] signal conversion 0x2196 Example: measure single shot, RH and T output only Write 0x2196 (hexadecimal) Command www.sensirion.com Version 1.1 – April 2021 17/22...

  • Page 18: Checksum Calculation

    > 0; --crc_bit) { Final XOR 0x00 (crc & 0x80) (crc << 1) ^ CRC8_POLYNOMIAL; Examples CRC (0xBEEF) = 0x92 else (crc << 1); return crc; Table 30 I C CRC properties. www.sensirion.com Version 1.1 – April 2021 18/22...

  • Page 19: Mechanical Specifications

    ± 0.3 ± 0.2 Table 31: Nominal dimensions and tolerances SCD4x (all in mm). The weight of the sensor is approx. 0.6 g. Note that the white protection membrane on top of the sensor must not be removed or tampered with to ensure proper sensor operation.

  • Page 20: Tape & Reel Package

    4.4 Moisture Sensitivity Level Sensirion SCD4x sensors shall be treated according to Moisture Sensitivity Level 3 (MSL3) as described in IPC/JEDEC J-STD- 033B1. Exposure to moisture levels or solder reflow temperatures, which exceed the limits as stated in this document, can result in yield loss and reliability degradation.

  • Page 21: Soldering Instructions

    IPC/JEDEC J-STD-020 with a maximum peak temperature of 235°C during up to 30 sec for Pb-free assembly in IR/Convection reflow ovens. Note that due to the comparably large size of the SCD4x sensor significant temperature differences across the sensor element can occur during reflow soldering. Specifically, the temperature within the sensor cap can be higher than the temperature measured at the pad using usual temperature monitoring methods.
  • Page 22 Warranty SENSIRION warrants solely to the original purchaser of this product for a period of 12 months (one year) from the date of delivery that this product shall be of the quality, material and workmanship defined in SENSIRION’s published specifications of the product. Within such period, if proven to be defective, SENSIRION shall repair and/or replace this product, in SENSIRION’s discretion, free of charge to the Buyer, provided that:...

Table of Contents