(完整版)基于PLC的水塔水位控制系统毕业设计论文

ABSTRACT

Based on PLC towers water level control system design

In the industrial and agricultural production process, often need to measure and control thewater level. Water level control applications in everyday life are very wide, such as water towers, groundwater, , it is the increase in water, relay towers used in the past, the water level automatic control system operation due to the frequent cause mechanical wear, convenient maintenance and updating can no longer meet the actual needs of the people, the paper used Siemens PLC S7-200 programmable controller as a series of small water tower water level automatic control system core, the water level of the tower the functions of automatic control system of the requirement analysis. Main achieved is through the actual water level sensor detects the water tower, specific information will be transmitted to the water level control module consisting of PLC, the A D conversion, to compare data, to control the pumping action of the motor, while data reduction, the indicated level specific information, if the water level lower or a set value, we will send the this paper, a water tank level control system design process, the water tower level control system based on PLC design a good implementation of the specific process.

KEY WORDS: Water level control, Siemens S7-200, The sensor

目 录

摘 要 ............................................................................................................................ I ABSTRACT .................................................................................................................. I 第1章 引 言 ................................................................................................................ 1 第2章 可编程器简介 ............................................................................................... 2

2.1可编程控制器的产生 .................................................................................................. 2 2.2 PLC的发展 ................................................................................................................... 4 2.3 PLC的基本结构 .......................................................................................................... 5

2.3.1 中央处理单元(CPU) ....................................................................................... 5 2.3.2 存储器 ................................................................................................................. 6 2.3.3 输入输出模块 ................................................................................................... 7 2.3.4 扩展模块............................................................................................................. 8 2.3.5 编程器 ................................................................................................................. 8 2.4 PLC的基本工作原理 ................................................................................................. 8 2.5 PLC的主要应用 .......................................................................................................... 9 2.6 S7-200系列PLC元件功能 .................................................................................... 10 第3章 水塔水位控制系统方案设计 ....................................................................... 13

3.1 传统水塔水位控制 ................................................................................................. 13

3.1.1 工作原理........................................................................................................... 13 3.1.2 外部接线与控制列表 .................................................................................... 13 3.1.3程序编辑及分析 .............................................................................................. 15 3.2 PID水塔水位控制系统的工作原理 ..................................................................... 15

3.2.1 设计分析 ........................................................................................................ 15 3.2.2 可行性试验 .................................................................................................... 16 3.2.3 可行性分析 .................................................................................................... 17

3.3 水位闭环控制系统 ................................................................................................. 17 第4章 PLC中PID控制器的实现 ........................................................................ 19

4.1 PID算法 .................................................................................................................... 19 4.2 PID应用 .................................................................................................................... 20 4.3 PLC实现PID控制的方式 .................................................................................. 20 4.4 PLC PID控制器的实现 ....................................................................................... 21 4.5 PID指令及回路表.................................................................................................. 23 第5章 系统硬件开发设计 ..................................................................................... 24

5.1 可编程控制器的选型 ............................................................................................. 24 5.2 EM235模拟量模块 ................................................................................................ 25

5.2.1 EM235的安装使用 .................................................................................... 27 5.2.2 EM235的工作程序编制 ........................................................................... 27 5.3 硬件连接图 ............................................................................................................... 28 5.4 控制系统IO地址分配 .......................................................................................... 28 第6章 系统软件应用设计 ..................................................................................... 29

6.1 水位PID控制的逻辑设计 ................................................................................... 29 6.2 梯形图编程 ............................................................................................................... 33 6.3 控制程序 .................................................................................................................... 33 6.4 联机 ............................................................................................................................. 33 第7章 结 论 .............................................................................................................. 35

7.1本课题研究结论 ......................................................................................................... 35 7.2课题存在问题与展望 ................................................................................................ 35 致 谢 ............................................................................................................................ 36 参考文献 ...................................................................................................................... 37 附录 .............................................................................................................................. 38