There are two main schemes for measuring temperature and humidity: wet-dry bulb method and electronic chemical sensor method. Following is a simple comparison of customers to choose their own humidity measurement methods.
The maintenance of wet and dry bulb wetting method is quite simple. In practical use, it is only necessary to add water to wet bulb regularly and replace wet bulb gauze. Compared with the electronic humidity sensor, the wet-dry bulb humidity measurement method will not produce aging, precision decline and other problems. Therefore, the wet-dry bulb method is more suitable for use in high temperature and harsh environment.
The electronic chemical moisture meter has developed rapidly in recent decades, especially in the past 20 years. The humidity sensor manufacturer must use standard humidity generator to calibrate the products before they leave the factory. The accuracy of the electronic chemical moisture meter can reach 2% to 13% RH.
In practical use, due to the influence of dust, oil pollution and harmful gases, a long time of use will result in aging and precision decline. The annual drift of humidity sensors is generally around (+2%) or even higher. Generally, the manufacturer will indicate that the effective use time of one calibration is one year or two years, and it needs to be re-calibrated when it expires.
The accuracy level of electronic chemical moisture meter should be judged by its long-term stability. Generally speaking, the long-term stability and service life of electronic chemical hygrometer are inferior to that of wet-dry bulb humidity sensor. Humidity sensor is based on semiconductor technology, so there is a requirement for the use of environmental temperature, which will cause damage to the sensor.
Therefore, the electronic chemical meter humidity measurement method is more suitable for clean and normal temperature occasions.