The Design And Implementation Of Industrial Fiber Grating Demodulation System

Since fiber grating sensor has the advantages of large capacity, light weight, resistance to electromagnetic interference, high electrical insulation and convenient for distributed measurement, it’s widely used in the areas such as smart structure, industrial manufacturing, biomedicine, natural ecology and human settlement environment. In recent years, the rapid advance of fiber grating sensor technology promotes the research on fiber grating sensor demodulation technology at home and abroad. At present, there have been products of fiber grating sensor demodulation on the market, which are based on different demodulation technology; however, they are either too expensive or too narrow in measuring range or with single function, which limits the application and popularity of fiber grating sensors in industrial applications, it is of important significance, that the research and realization of practical low-cost industrial fiber grating demodulation system.This article does intense research into fiber grating sensor demodulation system, devises the practical fiber grating demodulation system that is used in industry. This fiber grating sensor demodulation system is based on SOPC (System on a programmable chip) technology. It gives full play to its strong customizability, high speed of hardware description language, and high scalability of the system, so it’s suitable for industrial applications. The main research works are as follows:(1) Based on study of the development status of the fiber grating sensor demodulation technology at home and abroad, this article analyses the basic principles of fiber Bragg grating sensors and fiber grating sensor demodulation, and then does analyses and comparison of several common demodulation methods.(2) The scheme of fiber grating sensor demodulation is based on FPGA platform, which according to the features and functions of the industrial applications demand. It’s based on SOPC technology, and divided into five parts:FPGA unit, the optical unit, system power, photoelectric conversion as well as the underlying software.(3) Realizing the hardware circuits of each module, and completing the peripheral driver modules of SOPC system with hardware description language, designing the software of network communication and data processing and transmission of μC/OS Ⅱ operating system.(4) After completing of the various modules of the system software and hardware, doing test and analysis for the overall system in power consumption, demodulation effect, stability, and operating temperature range. Finally, making a brief summary for the work on this article and analyzing the inadequacies of the research, and putting forward the direction of the future work.The experimental results show that the fiber grating sensor demodulation system designed in this article has high performances. When it’s at the demodulation frequency of80Hz, the demodulation accuracy is±3pm, resolution is lpm. It’s proved that the scheme based on FPGA for low-cost industrial fiber grating sensor demodulation is feasible and practical.