SRAQ-D701 Multifunction Air Quality Sensor Module
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Specifications:
- Detection Parameters and Resolution: The CO2 value and
formaldehyde value measured by the module are equivalent value of
TVOC. - Pollutants: eCO2, PM2.5, PM10, Temperature,
Humidity, TVOC, CH2O - Measurement Resolution: CO2: 1 ppm, PM2.5: 0.3
ug/m3, PM10: 0.3 ug/m3, Temperature: 0.04%, Humidity: 1%, TVOC:
1230 ug/m3, CH2O: 500 ug/m3 - Measuring Range: CO2: 400~5000 ppm, PM2.5:
0~1000 ug/m3, PM10: 0~1000 ug/m3, Temperature: 5~100% RH - Accuracy: Refer to the user manual for
detailed accuracy specifications for each pollutant.
Product Usage Instructions:
Mounting:
Mounting type: Board mount. Hole diameter should be 2 mm with a
pitch of 11.5 mm.
Wire Connection:
| Sr. No. | Function | Notes | Color |
|---|---|---|---|
| 1 | VCC | 12-24 VDC, power supply positive | Brown |
| 2 | GND | Power supply negative | Black |
| 3 | RS485_A+ | Green | |
| 4 | RS485_B- | Blue |
Communication Protocol:
The module communicates using Modbus-RTU output.
Frequently Asked Questions (FAQ):
Q: What are the applications of the SRAQ-D701 sensor
module?
A: The sensor module is suitable for use in office and
commercial buildings, factory floors, laboratories, HVAC industry,
general air quality monitoring, and smart home systems.
Q: How can I contact customer service for assistance?
A: You can call us at 800.341.5266 or reach out via email at
customerservice@l-com.com.
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MULTIFUNCTION AIR QUALITY SENSOR MODULE (MODBUS)
User Guide for SRAQ-D701
Product Description
The SRAQ-D701 is a comprehensive air quality sensor module which combines CO2, laser dust, temperature and humidity, TVOC and formaldehyde. Developed for integration into air purifiers, air quality monitors and custom enclosures. The SRAQ-D701 provides real time concentration values via Modbus-RTU output. It offer good stability, and is well suited for applications where TVOC and particulate matter concentrations are a concern.
Features Detects multiple pollutants CO2, dust etc. Modbus output High reliability and good stability High accuracy & fast response Compact design for easy integration Applications Office and commercial buildings Factory floors Laboratories HAVC industry General air quality monitoring Smart home systems
Thank you for choosing L-com product. To ensure safe, accurate performance and product longevity, please take a moment to familiarize yourself with this manual before powering the device. Please keep it handy for future reference. In case of any questions regarding the installation or use of product, please call us at 800.341.5266. Reach out to us at customerservice@l-com.com and visit our website at www.l-com.com
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This datasheet has been downloaded from http://www.digchip.com at this page
M_L-com_SRAQ-D701-11/2022_R1.0
Technical Parameters
Detection Parameters and Resolution: The CO2 value and formaldehyde value measured by the module are equivalent value of TVOC, please pay attention when using or purchasing.
Pollutant
Measurement resolution
Measuring range
Accuracy
eCO2 PM2.5 PM10
1 ppm 0.3 ug/m3 0.3 ug/m3
400~5000 ppm 0~1000 ug/m3 0~1000 ug/m3
± 100 ppm ± 10% ± 10%
Temperature
0.01 °C
20~80 °C
± 0.5 °C
Humidity TVOC CH2O
0.04% 1 ug/m3 1 ug/m3
5~100% RH 1230 ug/m3 500 ug/m3
± 3% RH ± 90 ug/m3 ± 40 ug/m3
1. Working voltage: 5 ± 0.2 VDC 2. Working environment: Working temperature 0~50 °C, Working humidity: 15% RH 90% RH (no condensation) 3. Working environment: Temperature range -20~60 °C, Humidity: 5% RH 95% RH (no condensation) 4. Communication method: Modbus RTU RS485 5. Preheating time: 10-15 minutes, the longer the power-on time, the more stable the data will be.
Mounting Diagrams
Mounting type: Board mount. Hole diameter 2 mm, pitch 11.5 mm.
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Wire Definition
Port connector type is XH2.54mm pitch 4-pin terminal connector, 90° vertical mounted to PCB.
Sr. No.
Function
Notes
Color
1
VCC
12 24 VDC, power supply positive
Brown
2
GND
GND, power supply negative
Black
3
RS485_A+
RS485_A+
Green
4
RS485_B-
RS485_B-
Blue
Communication Protocol
The module hardware supports serial TTL communication interface and RS485 communication interface. When testing, users need to choose the corresponding communication method development according to the module interface type they have purchased. RS485 Interface Communication Interface Related Protocol: Serial port parameters: (9600/8/N/1) ModBus-RTU 485 The factory default address of the module is 0x01 Baud rate: 9600, Check bit: no, Stop position: 1 bit Return data time: <300ms The reading speed cannot exceed 350ms
Read Address Command
Receive
Fixed FE
Function Code 17
Fixed 00
Fixed 00
Fixed 00
Fixed 01
CRC_L
CRC_H
CRC Check
Fixed Function Code Number of Bytes Firmware Version Current Address CRC_L
CRC_H
–
Answer
FE
17
02
xx
yy
CRC Check
–
For example: Send command: FE 17 00 00 00 01 A0 06 Return data: FE 17 02 11 01 64 30 Indicates that the device address is 01 and the version number is V1.1
Modify Address Command
The factory default address of the module is 0x01, and the address range can be changed to: 0~254.
Receive Answer
Current Address
yy Address Before
Modification yy
Function Code
Fixed
Fixed
Reserved
Default Address CRC_L
CRC_H
06
00
00
00
zz
CRC check
Function Code Number of Bytes Keep Modified Address
CRC_L
CRC_H
–
06
02
00
Zz
CRC check
–
For example: When the current address is 01, the preset address is: 02 Send command: 01 06 00 00 00 02 08 0B Return data: 01 06 02 00 02 39 49
Read Data Command
Receive
Current Address Function Code
yy
03
Register Start Address
00
MM
Number of Sensors Required to Read
00
NN
CRC_L CRC_H CRC check
Current Address Function Code Data Length Sensor Data
CRC_L
CRC_H
–
Answer
yy
03
NN*2
xx xx ……xx xx
CRC Check
–
Note: The returned xx xx ……xx xx sensor data can be changed according to the register address and data length. 00 MM represents the register address of the sensor, and 00 NN is the data length.
00 00 eCO2
00 01 TVOC
00 02 CH2O
Register address00 MM
00 03
00 04
PM2.5
Humidity
00 05 Temperature
00 06 PM10
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Description
1. The minimum number of sensors 00 NN is 00 01, and the maximum is 00 07. When the MM value is 00, the maximum NN value can be 07. At this time, the value of all sensors can be read, and it can also be 01. When it is 01, only CO2 data can be read alone. And so on.
2. The address at the front of the register can read the data of the following sensor when the data length is increased, but the address at the back of the register cannot read the data of the sensor before this address. See details below:
00 MM 00 NN
Environmental data that can be read
00 00 00 01 00 00 00 02 00 00 00 03 00 00 00 04 00 00 00 05 00 00 00 06 00 00 00 07 00 01 00 01
Indicates that CO2 data is read from the starting address 00 00 Means to read CO2, TVOC data from the starting address 00 00 Means to read CO2, TVOC, CH2O data from the starting address 00 00 Means to read CO2, TVOC, CH2O, PM2.5 data from the starting address 00 00 Means to read CO2, TVOC, CH2O, PM2.5, H data from the starting address 00 00 Means to read CO2, TVOC, CH2O, PM2.5, H, T data from the starting address 00 00 Means to read CO2, TVOC, CH2O, PM2.5, H, T, PM10 data from the starting address 00 00 Indicates that the TVOC data is read from the starting address 00 01
00 01 00 02 00 01 00 03 00 01 00 04 00 01 00 05 00 01 00 06 00 02 00 01 00 02 00 02 00 02 00 03 00 02 00 04 00 02 00 05 00 03 00 01
Indicates that TVOC and CH2O data are read from the starting address 00 01 Means to read TVOC, CH2O, PM2.5 data from the starting address 00 01
Means to read TVOC, CH2O, PM2.5, H data from the starting address 00 01 Means to read TVOC, CH2O, PM2.5, H, T data from the starting address 00 01 Means to read TVOC, CH2O, PM2.5, H, T, PM10 data from the starting address 00 01
Indicates that CH2O data is read from the starting address 00 02 Indicates that CH2O and PM2.5 data are read from the starting address 00 02
Means to read CH2O, PM2.5, H data from the starting address 00 02 Means to read CH2O, PM2.5, H, T data from the starting address 00 02 Means to read CH2O, PM2.5, H, T, PM10 data from the starting address 00 02
Indicates that PM2.5 data is read from the starting address 00 03
00 03 00 02
Means to read PM2.5, H data from the starting address 00 03
00 03 00 03
Means to read PM2.5, H, T data from the starting address 00 03
00 03 00 04
Means to read PM2.5, H, T, PM10 data from the starting address 00 03
00 04 00 01
Indicates that the H data is read from the starting address 00 04
00 04 00 02
Means to read H, T data from the starting address 00 04
00 04 00 03
Means to read H, T, PM10 data from the starting address 00 04
00 05 00 01
Indicates that the T data is read from the starting address 00 05
00 05 00 02
Means to read T, PM10 data from the starting address 00 05
00 06 00 01
Indicates that PM10 data is read from the start address 00 06
How to Read a Frame of Data
For example, if the address of the module is 0x01, the user needs to send 01 03 00 00 00 07 04 08 to read out seven kinds of sensor data. The returned data format is as follows:
Byte[0]
Byte[1]
Byte[2]
Byte[3]
Byte[4]
Byte[5]
Byte[6]
Byte[7]
Byte[8]
–
Header Function Code Data Length
CO2 Data
TVOC Data
CH2O Data
–
0x01
0x03
0x0E
CO2_H
CO2_L
TVOC_H
TVOC_L CH2O_H
CH2O_L
–
Byte[9]
Byte[10]
Byte[11]
Byte[12] Byte[13]
Byte[14]
Byte[15] Byte[16]
Byte[17]
Byte[18]
PM2.5 Data
Humidity Data
Temperature Data
PM10 Data
CRC16 Check
PM2.5_H
PM2.5_L
Hum_H
Hum_L
Tem_H
Tem_L
PM10_H PM10_L CRC16_L
CRC16_H
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Calculation Method of Each Sensor Data
CO2 (ppm) = CO2_H * 256 + CO2_L TVOC(ug/m3) = (TVOC_H * 256 + TVOC_L) / 10 CH2O(ug/m3) = (CH2O_H * 256 + CH2O_L) / 10 PM2.5 (ug/m3) = PM2.5_H * 256 + PM2.5_L PM10 (ug/m3) = PM10_H * 256 + PM10_L Positive temperature (°C) = (Temperature_H * 256 + Temperature_L) / 10 For example: T = (0 x 0110) / 10 = 272 / 10 = 27.2
Negative Temperature (°C)
Method 1: Directly convert to a signed int type, for example: T = 0 x ffbf / 10 = -65 / 10 = -6.5 Method 2: If greater than 0 x 7fff (32767) Then it is a negative number T = (0 x ffbf – 65536) / 10 = (65471 – 65536) / 10 = -65 / 10 = -6.5 Humidity (%RH) = (Humidity_H * 256 + Humidity_L) / 10 For example: T = (0 x 02AD) / 10 = 685 / 10 = 68.5 %RH Note: If user need to use mg/m3 as the unit, please convert it. The conversion formula is: 1mg/m3 =1000 ug/m3 The length of the CRC check byte is 17 (that is, the bytes of Byte[0]~Byte[16]), select A001 or 8005 in reverse order.
Matters Needing Attention
1. Avoid contact with organic solvents (including silica gel and other adhesives), paints, pharmaceuticals, oils and high-concentration gases. 2. The module must not be subjected to excessive shock or vibration. 3. Do not apply this module to systems involving personal safety. 4. Do not install the module in a strong air convection environment.
CRC Check Calculation Method
Function function: CRC check function, generate CRC Parameter description: arr_buff: array set to be verified len: The length of the data to be verified Return parameter: CRC is an unsigned int type, the high byte is the high byte in front, and the low byte is in the back unsigned int CRC_Compute ( unsigned char *arr_buff, unsigned char len) { unsigned int crc=0xFFFF;
unsigned char i, j; for ( j=0; j <len;j++) {
crc=crc ^*arr_buff++; for ( i=0; i<8; i++) {
if( ( crc&0x0001) >0) {
crc=crc>>1; crc=crc^ 0xa001; } else crc=crc>>1; } } return ( crc); }
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Documents / Resources
 | L-com SRAQ-D701 Multifunction Air Quality Sensor Module [pdf] User Guide SRAQ-D701, SRAQ-D701 Multifunction Air Quality Sensor Module, Multifunction Air Quality Sensor Module, Air Quality Sensor Module, Sensor Module |