2. Sensor Calibration
For absolute concentration measurement, sensors accuracy can be affected by many factors such as reference
resistance difference, the sensitivity difference, temperature, humidity, interfering gases, aging time, therefore
they need regular calibration. For relative measurement calibration is not required. Because the sensor
characteristic curve is not linear, it is recommended in the whole range of multi-point calibration and consider
the influence of temperature and humidity. Once the calibration data obtained can be linear or polynomial fit to
organize the data.
Cautions
1 .Following conditions must be prohibited
1.1 Exposed to organic silicon steam
Sensing material will lose sensitivity and never recover if the sensor absorbs organic silicon steam. Sensors
must be avoid exposing to silicon bond, fixature, silicon latex, putty or plastic contain silicon environment.
1.2 High Corrosive gas
If the sensors are exposed to high concentration corrosive gas (such as H2S, SOX, Cl2, HCL etc.), it will not
only result in corrosion of sensors structure, also it cause sincere sensitivity attenuation.
1.3 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.
1.4 Touch water
Sensitivity of the sensors will be reduced when spattered or dipped in water.
1.5 Freezing
Do avoid icing on sensor’s surface, otherwise sensing material will be broken and lost sensitivity.
1.6 Applied voltage
Applied voltage on sensor should not be higher than 120mW, it will cause irreversible heater damaged, also
hurt from static, so anti-static precautions should be taken when touching sensors.
2 .Following conditions must be avoided
2.1 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’ sensitive will be decreased.
2.2 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.
2.3 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.
2.4 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.
2.5 Concussion
If sensors meet strong concussion, it may lead its lead wire disconnected.