The Realization of The Water Content Detector in Oil Based on Virtual Instrument Technique

摘要

Radio frequency capacitance sensor is usually used in the intelligent inspection of the water-content in oil product. This method depends on the dielectric constant of water is so much greater than that of the oil. In the process of the inspection, we found that the output of the sensor is not determined by the parameter of water content and it also changes when the temperature of environment is changes. That is to say the system has certain cross sensitivity about the environment which definitely affects measurement precision. Based on the theory of radio-frequency impedance and concerning the effect of temperature, a method of curved surface fitting is introduced. The results of experiment show that it is an effective way. At the same time, the Virtual Instrument (VI) mainly refers to develop instruments by software. Its major characteristics are flexibility, multi-functions, giving high performance, and less workload of bottom-program for using graph program language (LabVIEW). Therefore, the virtual instrument technique is a suitable platform to develop the water content detector in oil.