毕业论文基于PLC气体分析仪设计说明书.doc

摘 要 针对手动控制多路气体分析过程存在多路气体交叉污染、分析过程不流畅、分析过程耗时长、效率低等问题，设计了基于PLC控制器分析仪的多路气体在线分析控制系统，给出了控制系统的软硬件设计过程，实现了气体分析过程中气体采集、气路控制、气体数据处理过程的自动化作业、 PLC的气体分析仪 的总体方案，阐述了分析仪器能实现的各项功能，组成仪器各个部件，以及气体 分析仪软硬件的实现，包括PLC系统的器件选择，气体变送器及其信号调理电 路、气样采集系统、触摸式液晶屏程序和PLC程序的设计。 本方案通过人机交互界面，利用扩展的多个输入端口，采集多种气体浓度信号和温度、湿度、压力信号，利用数据模型进行数据运 算处理，仪器具有很强的环境适应性，能在温度、湿度、压力不稳定的环境中保 持较高的精度和稳定性。仪器具有多个输出端口，能对多个取样进口进行控制， 可通过巡回检测的方式实现对多个采样点的气体进行检测，并可根据应用需求对 采样路数进行扩展。 关键词：多种组份；多通道；PLC控制；气体分析仪器Abstract In order to solve cross-contamination of multi-gas, analysis process not smooth, time-consuming, low efficiency and other problems in the manual control process of multi-gas analysis, a multi-channel gas control and analysis system online-based on PLC controller is designed. The design process of hardware and software are given. The automation processes of gas collection, gas control and data processing is achieved. By analyzing advantages and disadvantages and applications of modem gas analysis instruments, in view of concrete demands，a new design proposal has been put forward in this paper, It makes the detailed introduction on the overall proposal of PLC-based gas analyzer, various functions, each components and the implementation of software and hardware, including the choice of PLC systems, and the designation of gas sensor and its processing circuit of the signal, gas collecting system, and the program of touchable LCD and PLC. It takes the man-machine interface， applies multiple extended inputting ports to collect signals of concentration, humidity, temperature and pressure on various gases and also employs the data model to carry out data calculation and handling. The instrument possesses the strong environmental adaptation and is able to keep high precision and stability in the environment of unsteady temperature, humidity and pressure. It also has multiple outputting ports to control the multiple sampling inlets, can detecte gas at several sampling points by means of scanning and extend the sampling routes acc