Winsen MD61 Thermal Conductor Gas Sensor User Manual

Winsen MD61 Thermal Conductor Gas Sensor User Manual

The MD heat conduction gas sensor is made according to the principle that the total thermal conductivity of the mixed gas changes with the content of the gas to be analyzed. The detection element and the compensation element are paired to form an arm of the bridge. The resistance of the detection element becomes smaller when it encounters a gas with a larger thermal conductivity than air, and when it encounters a gas with a smaller thermal conductivity than air (air background), the output voltage of the bridge changes, and the voltage variable increases with the gas concentration. It increases proportionally, and the compensation element plays a role of reference and temperature compensation.

Features

Linear output signal
Good repeatability and reliable performance
No catalyst poisoning
Detecting without Oxygen or short of oxygen

Application

To detect methane, hydrogen, and inert gas etc. on industrial sites.

Specification

Sensitivity and response characteristic

Output signal dependency on working voltage

Long term stability

The absolute value of the drift in air is less than 2 mV per year, in 10%CH4 the absolute value of drift is less than 2mV. For a short period storage (in 2 weeks), the sensor need 8 hours preheating to stabilize, for long-term (more than one year) storage, it need more than 48 hours’ preheating.

Cautions

Following conditions must be prohibited

1. High Corrosive gas
   If the sensors are exposed to high concentration corrosive gas (such as H2 S, SOX , Cl2, HCl etc.), it will not only result in corrosion of sensors structure, also it cause sincere sensitivity attenuation.

2. Alkali, Alkali metals salt, halogen pollution
   The sensors performance will be changed badly if sensors be sprayed polluted by alkali metals salt especially brine, or be exposed to halogen such as fluorine.

3. Touch water
   Sensitivity of the sensors will be reduced when spattered or dipped in water.

4. Freezing
   Do avoid icing on sensor’s surface, otherwise sensing material will be broken and lost sensitivity.

5. Applied higher voltage
   Applied voltage on sensor should not be higher than stipulated value, even if the sensor is not physically damaged or broken, it causes down-line or heater damaged, and bring on sensors’ sensitivity characteristic changed badly.

6. Connection in the circuit
   When the sensor is connecting into the circuit, connect the two pins in the middle as signal output, connect the other pin of the D(detector) part to negative electrode while take the other pin of the C( compensator) part to positive electrode.
   NOTE: The part marked “■ ” is detector(D) part while the other part is compensator (C) part.

Following conditions must be avoided

1. Water Condensation
   Indoor conditions, slight water condensation will influence sensors’ performance lightly.
   However, if water condensation on sensors surface and keep a certain period, sensors’ sensitivity will be decreased.

2. Used in high gas concentration
   No matter the sensor is electrified or not, if it is placed in high gas concentration for long time, sensors characteristic will be affected. If lighter gas sprays the sensor, it will cause extremely damage.

3. Long time storage
   The sensors resistance will drift reversibly if it’s stored for long time without electrify, this drift is related with storage conditions. Sensors should be stored in airproof bag without volatile silicon compound. For the sensors with long time storage but no electrify, they need long galvanical aging time for stability before using. If it is stored for half year or longer, the suggested aging time is one day before using.

4. Long time exposed to adverse environment
   No matter the sensors electrified or not, if exposed to adverse environment for long time, such as high humidity, high temperature, or high pollution etc., it will influence the sensors’ performance badly.

5. Vibration
   Continual vibration will result in sensors down-lead response then break. In transportation or assembling line, pneumatic screwdriver/ultrasonic welding machine can lead this vibration.

6. Concussion
   If sensors meet strong concussion, it may lead its lead wire disconnected.

7. Usage Conditions
   For sensor, handmade welding is optimal way. The welding conditions as follow:

   • Soldering flux: Rosin soldering flux contains least chlorine
   • homothermal soldering iron
   • Temperature: lower than 350℃
   • Time: less than 5 seconds

If disobey the above using terms, sensors sensitivity will be reduced.

Zhengzhou Winsen Electronics Technology Co., Ltd
Add: No.299, Jinsuo Road, National Hi-Tech Zone, Zhengzhou 450001 China
Tel: +86-371-67169097/67169670
Fax: +86-371-60932988
E-mail: sales@winsensor.com
Website: www.winsensor.com

Statement

This manual copyright belongs to Zhengzhou Winsen Electronics Technology Co., LTD. Without the written permission, any part of this manual shall not be copied, translated, stored in database or retrieval system, also can’t spread through electronic, copying, record ways. Thanks for purchasing our product. In order to let customers use it better and reduce the faults caused by misuse, please read the manual carefully and operate it correctly in accordance with the instructions. If users disobey the terms or remove, disassemble, change the components inside of the sensor, we shall not be responsible for the loss.
The specific such as color, appearance, sizes &etc, please in kind prevail. We are devoting ourselves to products development and technical innovation, so we reserve the right to improve the products without notice. Please confirm it is the valid version before using this manual. At the same time, users’ comments on optimized using way are welcome.
Please keep the manual properly, in order to get help if you have questions during the usage in the future.

References

• Winsen Gas Sensor_CO2 Sensor_Air Quality Sensor_Dust Sensor_CO Sensor-Winsen Electronics
• Winsen Gas Sensor_CO2 Sensor_Air Quality Sensor_Dust Sensor_CO Sensor-Winsen Electronics
• 郑州炜盛电子科技有限公司-可燃气体传感器_二氧化碳传感器_一氧化碳传感器

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