A Method to Measure Humidity Based on Dry-Bulb and Wet-Bulb Temperatures

This study tries to analyze the theory of measuring humidity based on dry-bulb and wet-bulb temperatures. And a theoretical formula is deduced for the calculation of relative humidity from dry-bulb and wet-bulb temperatures. Through analysis of the theoretical formula, a two-dimensional conversion table is produced to transform dry-bulb and wet-bulb temperatures into relative humidity. A method is proposed to obtain humidity by combining searching table and linear smoothing algorithm, which is suitable for rapid control. Error analysis and experimental data indicate that the relative error is less than 4%. The proposed method has certain value for humidity control in industrial control process.