毕业论文 PLC的液位控制的设计.docVIP

毕 业 论 文 题目： PLC的液位控制设计 所在学院： 计算机与电气自动化学院 所学专业： 电气工程及其自动化 摘 要 本次毕业设计的课题是基于PLC的液位控制系统的设计。 可编程逻辑控制器（Programmable Logic Controller，PLC），它采用一类可编程的存储器，用于其内部存储程序，执行逻辑运算、顺序控制、定时、计数与算术操作等面向用户的指令，并通过数字或模拟式输入/输出控制各种类型的机械或生产过程。 　可编程逻辑控制器实质是一种专用于工业控制的计算机，其硬件结构基本上与微型计算机相同，基本构成电源中央处理单元(CPU)存储器输入输出接口电路功能模块通信模块针对双容水箱普遍存在容积延迟问题和传统PID单回路控制难于达到控制要求的特点，提出了基于串级技术和PLC控制器的双容液位控制系统系统根据双容水箱的数学模型，采用微分先行的串级控制技术、PLC控制器、MCCS软件组态实现了双容水箱液位的高精度控制和实时显示 S7-300可编程控制器的硬件掌握，PID参数的整定及各个参数的控制性能的比较，应用PID控制算法所得到的实验曲线分析，整个系统各个部分的介绍和应用PLC语句编程来控制水箱水位。 关键词：S7-300西门子PLC、控制对象特性、PID控制算法、扩充临界比例法、压力变送器、电动调节阀、PID指令。 Abstract This graduation project topic is based on the PLC fluid position control system design. In the design, I am control the algorithm which the author primary cognizance the design, therefore designs in the paper with to the PID algorithm mentions many. Programmable Logic Controller，PLC,it uses a programmable memory, for its internal storage procedures, the implementation of logical, sequential control, timing, counting and arithmetic operations such as user-oriented instructions, and through digital or analog input / output control various types of machinery or production process. Programmable logic controller is a dedicated to the industrial control computer, and its hardware structure is basically the same with the micro computer, basic components: power supply, a central processing unit ( CPU ), memory, input and output interface circuit, function module, communication module. Aiming at the problem of capacious—lags in double—tanks， it was hard for the traditional PID control to the high stable constant requirements and cascade controlling could solve them. A new system based on cascade control of previous difference and PLC was investigated in industrial double—tanks. And this liquid—level control system used the previous difference algorithm of cascade controller， PLC and MCCS was designed according to the mathematical model of double tankThe this