《基于MODBUS协议的单片机控制系统》-毕业论文.doc

摘要 PAGE XLVIII 摘要 现场总线作为生产过程自动化发展的重点，对推动自动化技术起到巨大的推动作用，是现代化工业的标志。它作为工业数据通信网络的基础，沟通了生产过程现场设备之间的联系。MODBUS作为现场总线的一种通信协议，它实现了PLC控制器、工控仪表与设备间的通讯和信息交换，已经发展为全球工业领域最流行的协议之一。 本文设计基于MODBUS协议的单片机控制系统，实现PC机和单片机的通信，达到用PC机控制单片机的目的，构建了以PC机为主机，MODBUS协议为联络载体，单片机为从机的“主一从”式装置；设计了RS232和RS485的电平转换器，实现了PC串口和单片机串口的电平的兼容；采用CRC校检方法，保证了通信数据的准确性。针对MODBUS信息帧的特点，编程实现了主机和单片机以MODBUS协议的串行通信。设计合理，价格低廉，自主性强，在工业控制领域具有广泛的应用前景。 关键词：现场总线，MODBUS协议，CRC校检，串行通信，单片机 英文题目 ABSTRACT Field bus as the production process automation development focus, to promote the automation technology has played a tremendous role in promoting, modern industrial logo. It as industrial data communication network based on the production process field device, communication links between. MODBUS as a kind of field bus communication protocol, it implements PLC controller, industrial control instrumentation and the communication and the exchange of information, has developed into a global industry is one of the most popular protocols. In this paper, based on the MODBUS protocol design of the microcomputer control system, the realization of PC and MCU communication, achieve the PC control chip, built with PC as the host, the MODBUS protocol as the contact carrier, chip microcomputers as the from type device; design of RS232 and RS485 level converter, implementation the PC serial port and single-chip serial port level compatible; using CRC checking method, ensure the accuracy of data communication. According to the characteristics of MODBUS information frame, programming host computer and MCU with MODBUS protocol serial communication. Reasonable design, low price, autonomic sex is strong; in the industry control domain has the widespread application prospect. KEY WORDS: Field bus, MODBUS protocol, CRC checking, serial communication, single-chip microcomputer 前言 目　录 TOC \o 1-3 \h \z \u HYPERLINK \l _Toc326446180 前　言 PAGEREF _Toc326446180 \h 1 HYPERLINK \l _Toc326446181 第1章 绪论 PAGEREF _Toc326446181 \h 2 HYPERLINK \l _Toc32644618