摘  要:现场总线技术是当今自动化技术发展的热点之一，被人们誉为是自动化领域的计算机局域网。变电站的信息和数据共享以及采用实用、可靠、高效的通信网络和协议，可以使变电站自动化系统的功能得到优化，并且提高了变电站系统的自动化水平。随着电力网的扩大和计算机测控技术的不断发展，基于现场总线的测控系统将广泛的应用到电力系统的变电站中。

　　　本论文以CAN总线为基础，研究它在变电站测控系统中的应用原理，针对传统测控系统中存在的种种缺陷，设计了由CAN总线组成的现场总线型测控网络，并且论述了CAN总线技术的原理。测控单元完成的任务是把被检测的模拟信号转换成数字信号，并由计算机加工处理，以便进行控制、显示或打印。采用双CPU结构，一片CPU完成模拟量采集并处理、开关量输入/输出和人机接口功能，CPU1采用MOTOLOLA公司的MC68F333为核心处理器组成的应用系统。另一片CPU与CAN总线接口通信，就是给CAN总线发送数据以及接收CAN总线上传下来的数据同时还要做出处理。并应用SPI总线完成两CPU间的数据交换。CAN总线在变电站综合自动化系统中担负着重要任务，主要复杂测控网络的数据传输。

关键词：CAN总线  测控单元  双CPU  SPI总线

ABSTRACT:Field bus technology is one of the development of automation technology，Known as the computer local area network in automation field.Substation information and data sharing and the practical, reliable, efficient communication network and protocol, can make the substation automation system function has been optimized, and improves the level of automation of substation automation system..With the continuous development of the expanding of power network and computer control technology, control systems based on field bus will be widely applied to substation in power system.

　　　    This thesis is based on the CAN bus, the principle of its application in substation control system, aiming at the defects of the traditional control system, the design of field bus control network based on CAN bus, and discusses the principle of CAN bus technology.Measurement and control unit of the tasks is the analog signals are detected are converted into digital signals, and the computer processing, in order to control, display or print. Adopts double CPU structure, a CPU complete analog acquisition and processing, switch input / output and the man-machine interface, the application system of CPU1 using MC68F333 as the core processor.Another piece of CPU and CAN bus communication interface, that is to send data to the CAN bus and receiving CAN bus data and make the corresponding treatment. And the application of SPI bus to complete the data exchange between two CPU. In the substation automation system, hold the position of by measurement and control network CAN bus group is an important task of data transmission, so as to realize the telemetry, remote, remote control, remote adjustment function.

Keywords: CAN bus  Measurement and control unit   Double CPU     SPI bus