摘要随着科学技术的发展，现今诸多行业的研究应用在逐步地进行交融，电气工程及其自动化即是一个典型的代表。电力输送系统中正在越来越多地加入自动控制装置以减轻电力工作人员的劳动量。锅炉是化工、炼油、发电等工业生产过程中所不可或缺的重要动力设备，而锅炉液位的控制则是重中之重。可编程逻辑控制器（PLC）作为微电子技术与自动控制技术的的结合产物，在电力行业、工业制造、交通运输等领域应用颇为广泛。PLC中自带的PID调节功能更是广泛地应用到了锅炉水位与温度的调节系统中。85032

PID控制是一种典型的闭环控制，在较宽的调节范围内都具有出色的鲁棒性，且操作简单易行，在如今的工业生产领域得到了充分的运用。

本文对德国西门子公司生产的S7-200小型PLC进行研究，并将其运用到了浙大中控自主开发的CS4000小型锅炉控制系统实验平台中，以实现对锅炉系统中的液位控制。运用PLC的模拟量输入输出混合拓展模块EM235实现液位传感器模拟信号的采集，对单容、双容水箱液位特性进行测试，了解一阶与二阶系统的特点；针对单容、双容水箱进行PID控制；最终实现双容水箱的PID串级控制，并在MCGS人机界面进行参数手动调节。

毕业论文关键词  PLC  PID  MCGS  液位控制

毕业设计说明书外文摘要

Title  Design of the control system of a small boiler based on S7-200                   

Abstract As the development of science and technology, researches and applications of numerous industries are blended together step by step, such as Electrical Engineering & its AutomaTion。 More and more automatic devices are added into the power transmission system to reduce the workload of workers。 Boiler is an important power equipment in the chemical industry, oil refining, power generation and other industrial production, and the control of the liquid level in the boiler becomes more significant。 Programmable logic controller, as the combination of microelectronics technology and automatic control technology, is widely used in power industry, industrial manufacturing, transportation and so on。 And the function of PID tuning in PLC is more widely used in control of the boiler liquid level。

PID is a typical closed-loop control system。 It has a good robustness and is easy for operation。 So it is widely used in industry production。

In this paper, I research on the PLC S7-200 produced by SIEMENS, and apply it to the experiment platform CS4000 produced by SUPCON to realize the control of liquid level in the boiler system。I use EM235 to collect analog signal from the liquid level sensor, and then test the character of single-tank and double-tank water tanks to know the characters of first-order and second-order systems。 The PID control of single-tank and double-tank water tanks are also realized。 Finally, I make the PID cascade control of the double-tank water tank, and design the HMI by MCGS to manually adjust the parameters of PID。

Keywords  PLC  PID  MCGS   Liquid level control

目   次

1  绪论 1

1。1  课题研究背景和意义 1

1。2  国内外相关技术的发展趋势 1

1。3  课题主要研究内容 3

1。4  本章小结 3

2  S7-200小型PLC 4

2。1  S7-200的简要介绍 4

2。2  S7-200的硬件结构