数控磨床过程控制中plc的设计与实现.doc

数控磨床过程控制中PLC的设计与实现

摘    要
在机床数控系统中，数控装置是数控系统的核心，包括硬件以及相应的软件，用于实现各种控制功能。PLC在数控系统中是介于数控装置与机床之间的中间环节，根据输入的离散信息，在内部进行逻辑运算，并完成输出控制功能。PLC作为一种计算机控制系统，其拥有面向工业现场，具有更多、更强的I/O接口的特点，并且软件编程容易。PLC和CNC组成一体，充分的将PLC与CNC的优点相结合，实现功能更强的数字控制，并具有可靠性高、功能齐全、易于联网等显著的特点。本文结合数控磨床的改造，完成PLC系统的设计和实现。论文规划了系统的总体设计方案，选择了以PC+PLC为主的系统结构模型，根据系统的需求，选择了S7-200PLC,并确定了系统的通讯方式。
根据磨床的要求，完成了对PLC各种资源的分配，包括输入输出点的分配，系统信号的分类等。完成了对控制程序的编写，并进行了对一部分程序的调试。

关键词：PLC,通讯,信号,程序

ABSTRACT

In the CNC machine tools, NC device is the heart of the system, Including hardware and the corresponding software, used to achieve various control functions. PLC and CNC will be composed of one, can be more powerful digital control. PLC in the NC system is installed between the NC and the intermediate links between the machine, According to enter the discrete information, within the logic operation, and complete output control. LC as a computer control system, which has a field-oriented industries, with more and more I / O interface features, and software programming easy. PLC and CNC component integrates fully with the PLC will combine the advantages of CNC, and more powerful digital control and have high reliability, full-featured, easy networking, and other notable features. In this paper, CNC grinder with the design of the control system of the PLC were focused on the design. Papers planning the overall design of the system programme, chose to PC + PLC-based system model, according to the demand, choose the S7-200PLC, and to determine the system's means of communication.
    According to the requirements of grinding machine, the PLC has completed the distribution of resources, including input and output points of distribution, such as the classification system signal. Completed the control procedures in the preparation and conduct of the proceedings part of the debugging.

Key words：PLC, Communications, Signal, Procedures

目   录
摘    要 I
ABSTRACT II
1  绪论 1
1.1 PLC现状及发展趋势 1
1.2 PLC的应用 2
1.3课题研究背景 3
2 系统总体方案设计 4
2.1 研究内容 4
2.2 系统方案 4
3 系统硬件设计 5
3.1 PLC的结构 5
3.2 PLC的工作原理 7
3.3 系统硬件结构设计 8
3.3.1  PLC+PC的系统结构 8
3.3.2  PLC+PC系统与其他控制系统的比较 10
3.4 PLC通信 12
3.4.1 PLC常用的通信方式 12
3.4.2 PLC的以太网接入方式和传统总线连接方式的比较 14
4  PLC选型 17
4.1 PLC容量分析原则 17
4.2 PLC选型的依据 17
4.3 PLC选型 18
4.3.1 PLC比较 18
4.3.2  S7-200 PLC的功能概述 18
4.3.3  S7-200 PLC的特点 19
4.3.4  S7-200 PLC的硬件结构 19
4.3.5 S7-200 PLC的工作原理 20
5 系统软件设计 23
5.1  PLC的编程语言 23
5.2 Step7-Micro/WIN编程软件 23
5.2.1 软件概述 24
5.2.2 程序编辑器 24
5.3 输入输出点的分配 27
5.3.1信号的种类 27
5．3．2部分输入输出点的分配表 28
5.4 程序设计 28
5.4.1 程序结构 28
5.4.2实现功能 28
5.4.3 程序的编写 28
5.4.4 符号表 31
5.4.5 状态图 32
6 实验调试 33
7总结 36
参 考 文 献 37