毕业设计论文__基于PSD的浓度检测系统设计与分析.doc

文档介绍：SHANDONGUNIVERSITY OF TECHNOLOGY
毕业论文
基于PSD浓度检测系统设计与分析

摘要
目前,实时液体浓度检测技术相对来说还比较落后,因此研究新型的液体浓度检测系统具有十分重要的意义。工业生产中检测液体浓度的方法有比重法、化学分析法、超声波法及光学法等。但这些方法既费时又需繁琐的人工取采样,滞后性大,无法实现实时在线检测液体浓度,鉴于以上问题,本文设计了一种基于PSD的浓度检测系统。
浓度的变化会引起液体折射率的变化,对于固定的入射光线,折射率的变化会导致出射光线发生偏移,利用光电位置敏感器件检测出光线偏移量的大小,进而得到液体的折射率,从而计算出液体浓度,再由LED显示出来。本系统主要由半导体激光器、双隔离窗光学系统、PSD信号处理电路、基于8051单片机的A/D采集运算控制电路和显示电路等组成。双隔离窗光学系统采用两个隔离窗使光线在待测液体中两次折射,测量结果更精确;PSD信号调理电路主要由前置放大、加法器、减法器和除法器等部分构成,将对信号进行I/V变换和放大处理;基于8051单片机的A/D采集运算控制电路主要对PSD调理后的模拟量信号转变为数字量,并将信号输入至单片机进行分析处理,从而得到浓度值,最后由显示系统显示出来。
通过实验发现,光源强度和温度漂移对本系统的影响非常小,该系统具有结构简单、稳定性好、灵敏度高、响应时间快以及自动化程度高等优点,能够方便、准确地实现液体浓度的实时在线检测。本浓度检测系统可广泛应用在化工、制糖、食品、制药等诸多行业,是一种具有广阔发展前景的浓度检测系统。
关键词:位置敏感器件(PSD),半导体激光器,液体浓度,8051单片机
ABSTRACT
At present, real-time on-line liquid concentration detection technology is still relatively backward. Research of a new type of liquid concentration detection system is of great significance. The proportion of liquid concentration detected in the industrial production method, chemical analysis, optical method. However, these methods are time-consuming and tedious manual to take sampling lag, can not achieve real-time online detection of the liquid concentration, in view of the above problems, this paper designs a new type of concentration detection system based on position sensitive detector. In the chemical and pharmaceutical, light industry and beverage and environmental protection departments and the various fields of scientific research and national defense are to detect and control the parameters of the liquid concentration. At present, the proportion of liquid concentration detected in the industrial production method, chemical analysis, ultrasonic and optical method. However, these methods are time-consuming and tedious manual to take sampling lag, can not achieve real-time online detection of the liquid concentration, in view of the above problems, the designs a new type of concentration detection system based on position sensitive detector.