Introduction
The 3.3V methane laser sensor is designed using tunable diode laser absorption spectroscopy (TD-LAS), utilizing a 1653.7nm laser to detect methane via its distinct "fingerprint spectrum" absorption. It's resistant to interference from water vapor or other gases. By combining direct absorption and wavelength modulation technology, and employing an "N" type optical path structure, it achieves a long absorption path, ensuring high sensitivity and precision. The sensor also features a low-temperature laser, a photodetector, and a temperature compensation algorithm, making it adaptable to various environments. Its standardized interface and communication protocol enhance compatibility. This core component of methane detectors is ideal for applications in underground spaces, catering, industrial chemical sectors, and coal mines for gas leak detection and alarms.
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 |
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 |
Support and Services
Our Gas Detector Sensor services include expert assistance with troubleshooting and repairs, as well as maintenance, calibration, and testing to ensure precise operation. We provide product manuals and documentation, and offer guidance on selecting and customizing products. We aim to provide top-notch service to ensure your gas detectors operate effectively and reliably.
Packing and Shipping:
Product Packaging:
Gas Detector Sensor unit
User manual
Mounting hardware
Calibration certificate
Shipping Information:
Expected delivery time: 5-8 business days
