Target: CO2
Model: MH-711A
Detection range: 0~5% Vol optional
Detection principle: non-dispersive infrared (NDIR) principle
Characteristics: Detect combustible gas concentration matching with flame-proof marked detector in area 1&2 explosive environments which mix of ⅡA, ⅡB, ⅡC and T1-T6 flammable gases, vapors and air
Size: Φ44 mm×61 mm
Working conditions: 4.5~5.5V DC
Measurement range: 0~2000 ppm
0~6000 ppm
0~1% Vol
0~3% Vol
0~5% Vol
Resolution and accuracy: ±(50ppm+5% reading value)
Response time: T90 < 30 s
Notes: This product has been discontinued

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MH-711A is a universal type intelligent sensor to detect CO2 in air taking advantages of non-dispersive infrared (NDIR) principle. With high selectivity, no oxygen dependence, high performance and long lifespan features, MH-711A also has built-in temperature compensation feature. MH-711A is a compact and high-performance sensor based on infrared absorption of gas detection technology, micro-machining and sophisticated circuit design.


Widely used for industrial field instrumentation, industrial-process control and safety protection 


  • Long lifespan
  • High Sensitivity and resolution
  • 5V constant power supply, low power consumption
  • Output method: UART, analog voltage signal, etc.
  • Quick response & Resume
  • Temperature compensation, excellent linear output
  • Anti-poisons, anti-vapor interference
  • Detect combustible gas concentration matching with flame-proof marked detector in area 1&2 explosive environments which mix of ⅡA, ⅡB, ⅡC and T1-T6 flammable gases, vapors and air


Product Model MH-711A
Target Gas CO2
Working Voltage 4.5 V ~ 5.5V DC
Average Current < 100mA
Interface Level 3.3V
Measurement Range 0~30%VOL optional (view table 2)
Output Signal IIC
0.4-2V DC
Warm-up Time 3min
Response Time T90 < 30s
Working Temp. -40℃ ~ 70℃
Working Humidity 0 to 95%RH, Non-condensing
Dimension Φ44×61mm
Weight 350g
Life span >5 years
Ex-marking Ex dⅡC T6 Gb
Protected Class IP65

* The description and specifications might be changed without notice. Please contact us for the latest information before placing orders.

Technical Support:

Customized technical design and function, LOGO and package are available without extra charge (including molding fee) for mass volume.

The sensors don't have sleeping mode. It can be set in program if needed.

All Winsen products go through strict inspections and tests to make sure they are 100% qualified before shipping out.

The sensor has been fully tested (not calibrated) before leaving the factory. However, after transportation and storage, the environment conditions change, and the surface of the sensor absorbs moisture, mixed gas, pollution matters, etc. It is recommended that customers perform aging and calibration after sensors become stable according to the program and use occasions of the whole device.

15﹪-90﹪RH without condensation,greater or less than this range or long-term high temperature and high humidity will affect the life of the sensor.

Our sensors are certified with CE, 3C, ROHS, anti-explosion, fire prevention, and coal mining safety according to different applications. And we provide assistance for new certification.

Many factors can cause the sensor to fail such as broken wires in transportation, poisoning, falling off of the sensitive material, damage to the heating wire (device), etc. Please find specific cause in each category with Winsen’s aftersales.

Winsen provides professional consultation and service before and after sales. We will recommend the best fitting sensor for your demand. If you have any problem, don’t hesitate to email us to

Due to high volume of daily incoming emails and time zone difference, we may not be able to reply your emails immediately. But we will reply to your inquiry in 24 business hours.