基于基于Modbus总线的数据采集与控制系统的设计
毕业论文关键词 ModBus协议 RS-485 主机 从机 信息交流
Abstract
Field bus is fully industrialized today, one of the methods which used for the connection between the communication equipment is to improve the automation development focus in the information management level, to improve the current equipment use heavy and complicated, the disadvantage of poor real-time performance. Among them, the ModBus bus as the world's first truly used in industrial field bus protocol, a standard open, simple and compact frame format and can support a variety of electric equipment interface etc., gradually adopted by most of the inpidual with the manufacturers, and gradually become a product standard. Modbus protocol is a widely used in industrial manufacturing network protocol, the controller by the agreement between each other to complete data communication. It is mainly based on RS - 485 bus communication, between microcontroller and the communication between with other equipment. This topic using AT89C51 as the control core, between the host and four from the machine through the Modbus network based on RS - 485 communication, data acquisition and switch control system. First two by the relay of the machine is connected from the host key control, the current switch state real-time display in the host system, and then two each have two lines of A/D channel from the machine, its conversion value will also continue to refresh the display in the host system.
Keyword field bus RS-485 host slave The data collection system
目次
1. 绪论 6
1.1 数据采集系统的研究背景及实际意义6
1.2 数据采集系统的历史及研究现状6
1.3 课题要求8
2. 相关基本原理介绍9
2.1 RS-485简介9
2.2 RS-485选取理由10
2.3 ModBus协议9
3. 总体电路的硬件实现13
3.1 硬件设计流程13
3.2 硬件设计注意事项13
3.3 AT89C51单片机介绍14
3.4 主机电路15
3.6 从机1、2电路16
3.7 从机3、4电路16
3.8 显示系统电路17
4 软件程序设计18
4.1 软件设计思路与功能模块18
4.2 ModBus主机模块程序18
4.3 ModBus从机1、2模块程序19
4.4 ModBus从机3、4模块程序22
4.5 基于ModBus协议的数据采集仿真24
4.6 基于ModBus协议的数据采集及控制系统仿真26
总结29
致谢30
附录一 参考文献31
1. 绪论
1.1 数据采集系统的研究背景及实际意义
为了满足工业要求和生产发展需要，现代工业中对设备的安全性与可靠性有着严格的要求，为了满足安全需要，用户往往需要实时性的，精确的，可靠的了解设备运行情况，以便对安全隐患进行排查和对突发情况第一时间予以解决。在整个安全环节中，对工业生产中各种实时数据的采集是最为重要，要求最为严格的一环，所以，对整个工业生产环境的各种数据进行实时的监控与传输就成为安全工程的重中之重。