TDLAS型C2H2气体检测系统的光电检测电路研制

Development of Photoelectric Detecting Circuit for TDLAS Type C2H2 Gas Detection System

C2H2气体在生产生活中具有重要的地位,使用TDLAS技术进行C2H2气体的浓度检测是一种有效的高精度检测方法。本文针对TDLAS型的C2H2气体检测系统,研制了一种用于接收激光检测信号的光电转换电路。在激光信号被C2H2气体选择性吸收后,利用光电探测器将光信号转换为电流信号,再经前置放大电路得到有效的电压信号,之后利用ADS8320芯片将信号采集,并回传给主控芯片LPC2138进行数据处理,最后主控芯片使用RS422通讯将结果传送至上位机,并通过串口调试助手显示。经过实验验证整个电路能够稳定、实时地完成光信号到电信号的转化,其转换精度高,并且具有很强的灵活性,可以应用于其它气体的检测。

C2H2 is playing an important role on daily life and production of humankind. Applying TDLAS technology to detecting C2H2 gas concentration is an effective high-precision detection methods. In this paper,for the TDLAS type detection system of C2H2,a photoelectric conversion circuit for receiving the laser detection signal has been implemented. After the laser signal is selectively absorbed by C2H2,the photodetector is used to convert the optical signal into a current signal,and then the pre-amplifying circuit is used to obtain an effective voltage signal. After that,the signal is collected by the ADS8320 chip and returned to the main control chip LPC2138 for data processing,and finally the master control chip transfers the results to upper computer using RS422 communication,and displays them through the serial debugging assistant. The experimental results show that the whole circuit can stably accomplish the conversion from optical signal to electrical signal in real time with high conversion accuracy and strong flexibility,which can be applied to the detection of other gases.