Datasheet SGP30 (Sensirion) - 10

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Sensor Raw Signals
The command “sgp30_measure_raw” is intended for part verification and testing purposes. It returns the sensor raw signals which are used as inputs for the on-chip calibration and baseline compensation algorithms as shown in the functional block diagram in section 1.2. The command performs a measurement to which the sensor responds with 2 data bytes (MSB first) and 1 CRC byte (see
Figure 12
) for 2 sensor raw signals in the order H2 signal (sout_H2) and Ethanol signal (sout_EtOH). Both signals can be used to calculate gas concentrations c relative to a reference concentration cref by sref - sout c = cref ∙ exp ( ) 512 with sout the sensor raw signal for H2: sout = sout_H2 or for Ethanol: sout = sout_EtOH, and sref the H2 raw signal or Ethanol raw signal output at the corresponding reference concentration cref_H2 or cref_EtOh.
Humidity Compensation
The SGP30 features an on-chip humidity compensation for the air quality signals (CO2eq and TVOC) and sensor raw signals (H2 signal and Ethanol signal). To use the on-chip humidity compensation an absolute humidity value from an external humidity sensor like the SHTxx is required. Using the “sgp30_set_absolute_humidity” command, a new humidity value can be written to the SGP30 by sending 2 data bytes (MSB first) and 1 CRC byte. The 2 data bytes represent humidity values as a fixed-point 8.8bit number with a minimum value of 0x0001 (=1/256 g/m3) and a maximum value of 0xFFFF (255 g/m3 + 255/256 g/m3). For instance, sending a value of 0x0F80 corresponds to a humidity value of 15.50 g/m3 (15 g/m3 + 128/256 g/m3). After setting a new humidity value, this value will be used by the on-chip humidity compensation algorithm until a new humidity value is set using the “sgp30_set_absolute_humidity” command. Restarting the sensor (power-on or soft reset) or sending a value of 0x0000 (= 0 g/m3) disables the humidity compensation until a new humidity value is sent. Absolute humidity values dV in unit g/m3 can be calculated by the following formula: RH 17.62 ∙ T 100% ∙ 6.112 ∙ exp (243.12 d + T) v(T, RH) = 216.7 ∙ [ ], 273.15+T with temperature T and relative humidity RH.
Example
: Inserting T = 25°C and RH = 50% in the formula above results in the absolute humidity dV = 11.8 g/m3.
Feature Set
The SGP30 features a versioning system for the available set of measurement commands and on-chip algorithms. This so called feature set version number can be read out by sending a “sgp30_get_feature_set” command. The sensor responds with 2 data bytes (MSB first) and 1 CRC byte (see
Table 9
). This feature set version number is used to refer to a corresponding set of available measurement commands as listed in
Table 10
. Most significant byte (MSB) Least significant byte (LSB) Bit 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 Product type Reserved for 0 Product version SGP30: 0 future use
Table 9
Structure of the SGP feature set number. Please note that the last 5 bits of the product version (bits 12-16 of the LSB) are subject to change. This is used to track new features added to the SGP multi-pixel platform.
Measure Test
The command “sgp30_measure_test” which is included for integration and production line testing runs an on-chip self-test. In case of a successful self-test the sensor returns the fixed data pattern 0xD400 (with correct CRC). www.sensirion.com Version 1.0 – May 2020 – D1 10/19 Document Outline 1 Sensor Performance 1.1 Gas Sensing Performance 1.2 Air Quality Signals 1.3 Recommended Operating and Storage Conditions 2 Electrical Specifications 3 Interface Specifications The SGP30 comes in a 6-pin DFN package, see Table 4. 4 Absolute Minimum and Maximum Ratings 5 Timing Specifications 5.1 Sensor System Timings 5.2 Communication Timings 6 Operation and Communication 6.1 Power-Up and Communication Start 6.2 Measurement Communication Sequence 6.3 Measurement Commands 6.4 Soft Reset 6.5 Get Serial ID 6.6 Checksum Calculation 6.7 Communication Data Sequences 7 Quality 7.1 Environmental Stability 7.2 Material Contents 8 Device Package 8.1 Moisture Sensitivity Level 8.2 Traceability 8.3 Package Outline 8.4 Landing Pattern 8.5 Soldering Instructions 9 Tape & Reel Package 10 Ordering Information Revision History Important Notices Warning, Personal Injury ESD Precautions Warranty Headquarters and Subsidiaries