Research And Implementation Of Self-validating Method Of Turbidity Sensor Based On LabVIEW Platform

With the development of automatic and intelligent measurement and control system, the sensor is required for high accuracy, reliability and stabiliety, and a certain capacity of data processing, and is able to self-detection, self-correction and self-compensation. The research of sensor is developing toward miniature, integrated, intelligent and networked direction. A lot of new type sensors are emerged, such as intelligent sensors, fuzzy sensors, network sensors, virtual sensors etc. So far, people often assume that the output of the sensor is correct in the system, that is, sensor can only give the measured value of signal. But due to various uncertainties existed, the work state of sensor, the accuracy and reliability of measured value can be affected, which can not be given by these parameter sensors. Therefore, the international research direction of a new type sensor, namely self-validating(SEVA) sensor technology is emerged in recent years. Since the 1990s, many scholars in and abroad have been doing research and development work of self-validating sensor after its concept was proposed, where the University of Oxford in the control engineering laboratory do the most comprehensive, deep research in this area. The developed self-validating sensor includes the self-validating temperature sensors, the self-validating dissolved oxygen sensors, the self-validating turbine flowmeter and the latest developed self-validating digital Coriolis mass flowmeter.This paper first describes the concept, output parameters, features and research status of self-validating sensor, while the advanced virtual instrument technology based on LabVIEW in the area of measurement and control is introduced as the development platform of the subject. In addition, time series analysis method is one of the focus points of this paper, which establishes the theoretical foundation of for the posterior sensor model analysis. Another focus of this paper is how to establish a suitable sensor model and according to the features of self-validating sensor to propose a scheme of self-validating technology with hierarchical structure. In order to verify the technical scheme, it is applied to the turbidity sensor system and how to establish an independent and complete turbidity sensor self-validating system is also described in detail, including hardware platforms and software design. Moreover, the limitation fault, bias fault and cyclical interference fault are simulated based on the self-validating platform. The results show that this system can achieve its self-validating function. At the same time, it also shows the user-friendly operation interface, the easy operation of the system, and convenient observation and analysis of data.