Chen Ling-Hsi, Chen Chiachung
Taichung District Agriculture Research and Extension Station, 51541, Changhua County, Taiwan, ROC, Taiwan.
Department of Bio-industrial Mechatronics Engineering, National ChungHsing University, Taichung, 40227, Taiwan.
Sensors (Basel). 2018 Feb 21;18(2):637. doi: 10.3390/s18020637.
Humidity measurement is an important technique for the agricultural, foods, pharmaceuticals, and chemical industries. For the sake of convenience, electrical relative humidity (RH) sensors have been widely used. These sensors need to be calibrated to ensure their accuracy and the uncertainty measurement of these sensors has become a major concern. In this study, a self-made divided-flow generator was established to calibrate two types of electrical humidity sensors. The standard reference humidity was calculated from dew-point temperature and air dry-bulb temperature measured by a chilled mirror monitor. This divided-flow generator could produce consistent result of RH measurement results. The uncertainty of the reference standard increased with the increase of RH values. The combined uncertainty with the adequate calibration equations were ranged from 0.82% to 1.45% RH for resistive humidity sensors and 0.63% to 1.4% for capacitive humidity sensors, respectively. This self-made, divided-flow generator, and calibration method are cheap, time-saving, and easy to be used. Thus, the proposed approach can easily be applied in research laboratories.
湿度测量是农业、食品、制药和化工行业的一项重要技术。为方便起见，电相对湿度（RH）传感器已被广泛使用。这些传感器需要进行校准以确保其准确性，并且这些传感器的测量不确定度已成为一个主要问题。在本研究中，建立了一个自制的分流发生器来校准两种类型的电湿度传感器。标准参考湿度由冷镜监测仪测量的露点温度和空气干球温度计算得出。该分流发生器能够产生一致的RH测量结果。参考标准的不确定度随着RH值的增加而增大。对于电阻式湿度传感器，采用适当校准方程时的合成不确定度范围为0.82%至1.45%RH，对于电容式湿度传感器则为0.63%至1.4%。这种自制的分流发生器和校准方法成本低廉、省时且易于使用。因此，所提出的方法可以很容易地应用于研究实验室。
