Ⅱ. Cautions for Use of NDIR-type Gas Sensors

【Conditions for use and storage】

1. 1) Rated temperature and humidity conditions
   Using or storing the sensor in an environment outside the rated temperature and humidity range may cause physical damage and/or affect the sensor characteristics.
2. 2) Storage conditions
   Store the sensor in an antistatic package or container.
3. 3) Condensation
   Sensor characteristics may change if the sensor is exposed to dew condensation.
4. 4) Freezing
   Sensor characteristics may change if water freezes on the surface or inside the sensor.
5. 5) Organic vapors
   If the sensor is exposed to organic vapors generated from alcohol, acetone, volatile oil etc., organic vapors will adsorb onto the sensing element surface, and sensor performance may be affected.
6. 6) Dusts and oil mist
   Sensor performance may be affected if exposed where excessive dust, fine particles, or oil mist is present.
7. 7) Alkaline metals
   Sensor characteristics may be changed if the sensor is contaminated by alkaline metals. Avoid contamination by alkaline metals, especially salt water spray.
8. 8) High concentration of corrosive gases
   Sensor performance may be affected if exposed to a high concentration of sulfur-based or chlorine-based corrosive gases for extended periods. Avoid usage and storage in highly corrosive environments.

【 Handling 】

1. 1) Applied voltage
   If higher than the rated voltage is applied to the sensor, the sensor may be damaged or sensor characteristics may be irreversibly impaired. Do not use the gas sensor if excessive voltage is applied.
2. 2) Mechanical shock and vibration
   Avoid mechanical shock. The optical cell may undergo some deformation if the sensor is subjected to a shock or vibration. Do not use the sensor if subjected to a drop or other mechanical shock.
3. 3) Transportation
   Sensors should be packed firmly for prevention of mechanical shock and vibration during transportation, using antistatic cushioning materials for wrapping the sensor.
4. 4) Electro static discharge
   The sensor may be damaged if subjected to ESD (Electro Static Discharge). Take appropriate precautions and measures against ESD in handling the sensor.
5. 5) No soaking
   Avoid contact with water. Sensor characteristics may be affected due to soaking or splashing the sensor with water.
6. 6) No disassembly or deformation
   Under no circumstances should the sensor be disassembled, nor should the sensor structure be deformed. Such action would void the sensor warranty.
7. 7) Mechanical stress
   When handling, the optical cell should never be touched. Under no circumstances should mechanical stress be applied to the optical cell or the PCB. Any distortion of the sensor may affect sensor characteristics.
8. 8) Gas inlet
   Do not block the gas inlet of sensor. The sensor would not work properly with a clogged inlet.
9. 9) Gas inlet
   Do not remove the non-woven filter on the sensor top.

【 Mounting process 】

1. 1) Soldering
   The sensor should be installed into a circuit by manual soldering only. Wave soldering or reflow soldering should not be used.
2. 2) Electro static discharge
   Exercise necessary precaution against ESD during mounting of the sensors on finished instruments.
3. 3) Resonance
   Excessive vibration may cause deformation of the sensor at the resonance frequency, leading to sensor characteristics change. Usage of compressed air drivers or ultrasonic welders on assembly lines may cause such vibration to the sensor. Before using such equipment, preliminary tests should be conducted to verify that there will be no influence on sensor characteristics.

【 Application design 】

1. 1) Preheating time
   As unpowered storage becomes longer, a longer preheating period is required to stabilize the sensor before usage.
2. 2) Heat generation
   The light source inside the gas sensor generates heat. A temperature sensor or a humidity sensor mounted close to the gas sensor may result in erroneous temperature or humidity measurement. Temperature and humidity sensors should be mounted at a sufficient distance from the gas sensor.
3. 3) Atmospheric pressure
   The sensor has pressure and altitude dependency. Compensation for atmospheric pressure and altitude is needed to obtain high accuracy under pressures different from normal atmospheric pressure or under altitudes other than 0m.
4. 4) Electrical noise
   ESD protection devices are not included in the sensor's electronics. Add appropriate protection devices such as zener diode, varistor etc. to host electronics according to the requirements of intended applications.
5. 5) Explosion protection
   The sensor does not fulfill technical requirements of industry standards for explosion protection. When the sensor will be used in explosive atmospheres, consider using an appropriate external explosion-proof enclosure according to the zone classification of where the sensor is intended to be used.
6. 6) Foreign conductive objects
   If foreign conductive objects get into the optical cell, short-circuit may occur. When such conditions are expected to be encountered, installation of an external air filter is recommended.
7. 7) Fitness for purpose
   Before usage of the sensor, customers should verify and ensure that the sensor will work properly under the conditions where they intend to use it and that the sensor is fit for the purpose for which customers wish to use it.