摘要：PLC是一种应用十分普及的自动控制装置，它把自古以来的继电器控制技艺、计算机技术和交流技术融为一体，具有通用性强、操作简便、使用范围广、可靠性高、抗干扰能力强，非常适合温度控制的要求。
在工业领域，随着自动化程度的迅速提高，过程控制系统的用户对监控的要求越来越高，人机界面的出现，恰好能满足用户的需求。人机界面控制系统进行全面的监控，包括过程监控，报警，数据记录等功能，从而使控制系统变得人性化的操作，过程可视化，自动化控制领域日益显著。
本设计主要介绍了基于西门子公司S7-200系列的可编程控制器和北京三文力控公司的组态软件力控（FC）的控制系统的设计方案。运用PID算法，编程使用PLC的梯形图进行编程，使合成塔的自动控制得到实现，让程序更为简洁，运行速度更为理想。利用力控组态软件设计监控界面，实现控制系统的实时监控、数据的实时采样与处理。
毕业论文关键字：合成塔控制系统；温度控制；可编程控制器；PID
Methanol production automation design
Abstract：Programmable controller is an automatic control device application is very popular, it is the traditional relay control technology, computer technology and communication technology integration, has the versatility, ease of use, wide adaptation, high reliability, anti-jamming ability, very suitable for temperature control.
In the industrial field, with the rapid increase in the degree of automation, process control system user to monitor the increasingly high demand, the emergence of human-machine interface, just to meet the needs of users. Man-machine interface control system to conduct a comprehensive monitoring, including process monitoring, alarm, data logging, and other functions, so that the control system becomes user-friendly operation, process visualization, automatic control in areas increasingly significant.
This design introduces the Siemens S7-200 series based on programmable controllers and Beijing three dimensional strength controls configuration software company force control (FC) of the control system design. Using PID algorithm, using PLC ladder programming language, to achieve automatic control of temperature synthesis column, makes the program more compact, runs more desirable. The strength controls configuration software designed user interface, real-time monitoring control systems, real-time sampling and data processing.
KeyWords：synthesis tower control system;temperature control;programmable controller;PID
目录
1 绪论    1
1.1甲醇介绍    1
1.2 甲醇生产工艺简介    1
1.3 温控系统的现状    1
1.4 设计主要内容    2
2 PLC和组态基础    4
2.1 可编程控制器基础    4
2.1.1 可编程控制器的产生和应用    4
2.1.2 可编程控制器的组成和工作原理    4
2.2 组态软件    6
2.2.1力控组态软件简介    6
2.2.2 力控组态软件的特点    6
3 总设计思路    8
3.1 控制方案    8
3.1.1 被控变量的选择条件    8
3.1.2 操纵变量的选择条件    8
3.2控制对象    8
3.3  PID控制流程图    9
3.4   PLC控制系统的软件设计    10
3.4.1 PLC程序的设计方法    10
3.4.2  编程软件STEP7--Micro/WIN 概述    10
3.4.3 程序设计    12
3.5 PLC控制系统的硬件设计    16
3.5.1 PLC控制系统设计的基本原则和步骤    16 PLC甲醇生产自控设计+梯形图:http://www.youerw.com/zidonghua/lunwen_34657.html