Introduction
Using TD-LAS technology, the 3.3V methane laser sensor detects gas
through a 1653.7nm laser by absorbing methane's unique "fingerprint
spectrum." It resists interference from water vapor and other
gases, combining direct and wavelength modulation absorption
techniques for high sensitivity. Its "N" type optical path
structure allows for a longer absorption path, enhancing precision.
Low-temperature laser devices and a temperature compensation
algorithm ensure adaptability across different environments.
Featuring a standardized interface and communication protocol, this
sensor is a core element in methane detection for underground
spaces, industries, and mines.
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 technical support and services offer expert
help for troubleshooting and resolving issues, along with repair
and maintenance. We also provide calibration and testing to
guarantee precise readings, as well as access to product
documentation and manuals. Additionally, we assist with product
selection and customization to meet your needs. We are dedicated to
providing top-tier support to ensure your gas detector sensors
perform optimally.
Packing and Shipping:
Product Packaging Includes:
- Gas Detector Sensor device
- Instruction manual
- Mounting accessories
- Calibration certificate
Shipping Details:
- Estimated delivery time: 5-8 business days
