质谱数据采集系统的研究

发布时间：2018-08-08 20:50

【摘要】：质谱仪是一种利用荷质比分离检测物质的分析仪器,被广泛应用于能源、制药、生命科学和空间探测等领域。它的工作原理是通过数据采集系统获取检测器的输出信号,再由计算机对数据进行分析处理,最后得到完整的质谱图。依据课题要求,本文从便携式离子阱质谱仪工作原理出发,通过对信号同步控制,数据存储等数据采集技术关键技术的研究,研制了一套改进型的数据采集系统。本文将质谱数据采集系统主要分为控制模块、信号处理模块、数据采集模块、通信模块。控制模块实现整个系统的信号控制,重点研究了按照系统时序的多信号同步控制;信号处理模块主要实现对检测器输出的微弱信号进行电流-电压转换、放大、滤波等处理使其达到ADC芯片的采集要求;数据采集模块实现原始信号的采集和存储,其中质谱数据的存储采用了直接内存访问技术(Direct Memory Access,DMA),该技术提高了CPU的工作效率,解决了传输速率不匹配问题;通信模块采用以太网W5500实现上层软件与下位机的数据通信和质谱数据的传输,采用RS-485串口方式实现分子泵的开关控制和数据读取,W5500满足了数据传输带宽要求,保证了通信的稳定性。本文针对不同模块分别从硬件、软件设计两方面进行了分析和探索。对射频控制信号、射频辅助信号(AC信号)的产生进行了实验验证。本文最后对各模块进行了硬件测试和代码调试,包括同步时序控制、射频信号控制、信号的采集和处理及以太网通信等功能。测试结果表明,各模块的信号输出稳定且精确度高。此外,通过集成测试,系统在设定时间内完成了信号控制和采集任务,满足本课题的设计要求。
[Abstract]:Mass spectrometer (MS) is a kind of analytical instrument which uses the ratio of charge to mass to separate and detect substances. It is widely used in the fields of energy, pharmacy, life science and space exploration. Its working principle is to obtain the output signal of the detector through the data acquisition system, then analyze and process the data by the computer, and finally obtain the complete mass spectrogram. According to the requirements of the project, a set of improved data acquisition system is developed based on the working principle of portable ion trap mass spectrometer and the research on the key technology of data acquisition such as signal synchronization control and data storage. In this paper, the mass spectrum data acquisition system is divided into control module, signal processing module, data acquisition module, communication module. The control module realizes the signal control of the whole system, focusing on the multi-signal synchronization control according to the time sequence of the system, the signal processing module mainly realizes the current-voltage conversion and amplification of the weak signal output by the detector. The data acquisition module realizes the acquisition and storage of the original signal, in which the direct memory access technology (Direct Memory) is used to store the mass spectrum data, which improves the efficiency of the CPU. The communication module uses Ethernet W5500 to realize the data communication between the upper software and the lower computer and the transmission of mass spectrum data. The switch control and data reading W5500 of molecular pump are realized by RS-485 serial port mode, which meet the requirement of data transmission bandwidth and ensure the stability of communication. In this paper, the hardware and software design of different modules are analyzed and explored. The generation of radio frequency control signal and radio frequency auxiliary signal (AC signal) is verified experimentally. Finally, the hardware test and code debugging of each module are carried out, including synchronous timing control, RF signal control, signal acquisition and processing, Ethernet communication and other functions. The test results show that the signal output of each module is stable and accurate. In addition, through the integrated test, the system completes the task of signal control and acquisition in the set time, which meets the design requirements of the subject.
【学位授予单位】：宁波大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TP274.2;TH843

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