基于C8051 f040单片机的光离子化气体浓度检测电路设计∗

摘要

Gas concentration can be measured by detecting the photoionization micro-current. C8051f040 microcon-troller is used as the core device,using the internal ADC and signal acquisition unit to design a measurement system that can be measured gas concentration within the range of 0~200×10-6 and real-time detection with digital display. The system by using the metal shielding signal acquisition unit and in the software programming combining sam-pling,digital filtering method improved the SNR of the system. In computer automatic distribution system the con-centration of dimethyl ether is tested,which showed the error did not exceed the scope of 0.07×10-6,together with fast response and reliable work made it work properly in the practical application.%对光离子化气体浓度的测量,本质上是对其产生的微电流的测量。为此以C8051f040单片机为核心器件,采用内部ADC、信号采集单元设计一种测量系统,可以对0~200×10-6量程范围内的待测气体浓度实时检测并用数码管显示。该系统通过金属屏蔽信号采集单元和在软件编程中采用过采样、数字滤波相结合的方法来提高系统的信噪比。在计算机自动配气系统中测试了二甲醚的气体浓度,误差范围≤0.07×10-6,响应速度快、工作可靠、可作为实际应用。