Introduction
Developed using TD-LAS, the 3.3V methane sensor relies on a 1653.7nm laser to detect methane via its distinctive "fingerprint spectrum" absorption, offering resistance against interference from water vapor or other gases. By merging direct absorption and wavelength modulation techniques with an "N" type optical structure, it achieves a long absorption path, high sensitivity, and precision. The low-temperature laser and photodetector, paired with a temperature compensation algorithm, enhance its environmental adaptability. Its standard communication and installation features make it broadly compatible for methane monitoring in industrial, mining, and underground applications.
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
Gas Detector Sensor technical support includes expert assistance for troubleshooting and resolving issues, repair and maintenance services, and calibration and testing to guarantee accurate performance. We offer product manuals and documentation, along with guidance for product selection and customization. Our goal is to deliver exceptional support, ensuring your gas detectors work effectively.
Packing and Shipping:
Product Packaging:
Gas Detector Sensor unit
User manual
Mounting hardware
Calibration certificate
Shipping Information:
Expected delivery time: 5-8 business days
