Introduction
The 3.3V methane sensor, using TD-LAS technology, detects methane through its "fingerprint spectrum" with a 1653.7nm laser, avoiding interference from water vapor and other gases. Combining direct and wavelength modulation absorption techniques, along with an "N" type optical path design, it achieves high sensitivity and precision. It incorporates low-temperature laser components and a temperature compensation algorithm for wide environmental adaptability. With standardized communication protocols and a threaded installation interface, this sensor is versatile and suitable for methane leak detection in coal mines, chemical plants, restaurants, and underground areas.
Feature
• High detection accuracy
Direct and wavelength modulation technology combined with folded optical path design, measurement error ≤±6% true value @25℃
• Good environmental adaptability
Wide temperature compensation correction algorithm, can meet -40~+70℃ application
• Strong anti-interference
Methane "fingerprint spectrum" laser absorption detection technology, anti-poisoning, anti-water vapor and other gas interference;
• Strong structural protection
Stainless steel material design, meets the explosion-proof level Exia IIC T6 Ga
• Low cost
Long service life, low power consumption, modular design, easy to integrate
Dimensions
Technical Parameters:
| Parameters | Technical Indicators |
| Measuring gas | Methane |
| Measuring principle | TD-LAS |
| Detection mode | Dispersive |
| Measuring range | 0-20% VOL (customizable) |
| Measurement error @25℃ | <+0.06%VOL,0-1%VOL
<+6%True value,1-20% VOL |
| Lower detection limit | 0.2% VOL |
| Minimum resolution | 0.01% VOL |
| Response time | T90<15s |
| Operating voltage | 3.0VDC ~3.6VDC |
| Average operating current | <30mA |
| Peak current | <210mA |
| Output mode | Standard TTL serial port |
| Operating temperature | -40℃~ +70℃ |
| Operating humidity | 0 ~ 99% RH (condensation) |
| Explosion proof sign | Ex ia IICT6 Ga |
| Intrinsic safety parameter | Ui:3.3V Ii:50mA
Pi:0.250W Ci:20uF
Li:3.14uH |
| Protection degree | IP66 |
| Product weight | 255g |
| Products dimensions | φ41.7mmx63.6mm |
Applications:
a) The sensor continuously outputs the measured methane concentration, measured temperature, measured pressure, laser signal strength, laser operating temperature and fault code through the standard TTL serial port
b) It has a self-test function, which can detect whether the laser, photoelectric detector and voltage stabilization sensor are normal, which helps to eliminate the fault point.
Communication Interface and Definition
Interface form: SH1.0mm/4P
Cable length: 200mm
| Number | Color | Interface definition |
| 1 | Red | VCC |
| 2 | Black | GND |
| 3 | Blue | RX |
| 4 | Green | TX |
Communication Protocol
(1) Communication interface configuration
UART serial port: Baud rate: 115200, data bits: 8 bits,
Stop bit: 1 bit, parity bit: no check
(2) Description of communication protocol
| Byte sequence number | Function code | Byte number | Unit | Example |
| 0 | Head of frame | 1 | - | A |
| 1-7 | Concentration | 7 | %VOL | +000.00 |
| 8 | Blank space | 1 | - | <SP> |
| 9-13 | Ambient temperature | 5 | ℃ | +23.7 |
| 14 | Blank space | 1 | - | <SP> |
| 15-21 | Ambient air pressure | 7 | hPa | 1006.22 |
| 22 | Blank space | 1 | - | <SP> |
| 23-27 | Intensity of light | 5 | - | +16.1 |
| 28 | Blank space | 1 | - | <SP> |
| 29-35 | Gain coefficient | 7 | - | B+6.0 |
| 36 | Blank space | 1 | - | <SP> |
| 37-38 | Fault code | 2 | - | 00 |
| 39 | Blank space | 1 | - | <SP> |
| 40-41 | Xor check code | 2 | - | 3D |
| 42 | Carriage return character | 1 | <CR>: | <CR>: |
| 43 | Line break character | 1 | <LF> | <LF> |
After the sensor is powered on, it goes through a period of preprocessing (6-10s) and then begins to periodically (1Hz) output a fixed-length string. The string format is shown in the figure above.
Output string parsing (sample):
A 000.00 + 24.0 + 1006.22 + 16.1 + 006.0 B 00 13
A: the frame head;
+000.00: methane concentration value, two decimal places reserved, unit %vol;
+ 24.0: the environment temperature, the unit ℃;
1006.22: the environment pressure, the unit hPa;
16.1: the laser light intensity and effective range 3.6 21.6;
006.0: magnification factor, normal range 1.0-126.0;
00: fault codes
01: abnormal optical signal; 02; Ambient temperature or abnormal pressure; Optical signal is too strong; 04 laser temperature anomaly;
05: light signal is too weak;
13: xor check code
Fault Code
| Fault code | Meaning | Fault code | Meaning |
| 0 | Sensor working properly | 3 | The laser signal is strong |
| 1 | The photodetector signal is abnormal | 4 | Laser temperature anomaly |
| 2 | Temperature and pressure sensor abnormal | 5 | The laser signal is too weak |
Precautions
a) The working voltage of the sensor is 3.3V, and the serial interface level is 3.3V;
b) sensor contains precision optical components, please avoid violent collision;
c) Working environment conditions: -40℃ ~ +70℃
d) Relative humidity 0-99% RH (non-condensation).
Note: The working voltage of the sensor is 3.3V. It is forbidden to connect the power supply voltage exceeding 3.6VDC to the sensor to avoid damage to the sensor.
Support and Services
Our Gas Detector Sensor support services include professional troubleshooting, repairs, and routine maintenance. Calibration and testing are available to ensure accuracy, while we also provide detailed product documentation and manuals. We offer guidance on selecting and customizing products. Our commitment is to provide high-quality service, ensuring your sensors function smoothly and efficiently.
Packing and Shipping:
Product Packaging:
Gas Detector Sensor unit
User manual
Mounting hardware
Calibration certificate
Shipping Information:
Expected delivery time: 5-8 business days
