基于单片机和CAN总线的企业现场信息监控系统.doc

基于单片机和CAN总线的企业现场信息监控系统 —智能节点部分 摘 要CAN通信控制芯片SJA1000与ATMega8L单片机接口构成的CAN总线系统智能节点部分。其硬件电路主要由4部分组成：CAN控制器、CAN总线收发器以及光电隔离器。主要功能是各智能节点采集现场仪表设备的过程参数，将数据经CAN总线发送到上位机，进而实现对企业生产现场信息的实时采集与实时监控。 本文首先介绍了企业现场信息监控系统的组成以及CAN现场总线；其次对现场信息检测的实现及单片机最小系统的各个接口电路作了简要介绍；然后对CAN通信模块的核心器件CAN总线控制器SJA1000和收发器PCA82C251作了详细的介绍；最后对系统的软件设计和系统调试进行了说明分析。 关键词：ATMega8L；CAN总线；智能节点；SJA1000 The monitoring system of the field information of enterprise based on MCU and CAN bus ?Part of intelligent node Abstract In this paper, a monitoring system of field information of enterprise based on MCU and CAN bus is designed. In general ,the structure of the system is divided into three parts, the enterprise network, the engineer station, the smart node. This article focuses on the design of the CAN bus communication with ATMega8L and SJA1000 consisting of the smart nodes. The hardware have 4 major parts：microprocessor, CAN controller, CAN bus transceivers and optoelectronic isolator. TMain function of hardware is to capture the field information, the data will be sent to the MCU and engineer station,finally,MCU receives the orders and execute it. This paper introduces the field information monitoring system and CAN fieldbus, followed by the smallest single-chip microcomputer system of the various parts are briefly introduced; then the core of CAN communication module CAN bus controller SJA1000 device and the transceiver devices made PCA82C251 detail; Finally, the system software design and system analysis of debugging are described; Key words：TMega8L; CAN bus;Smart Node ; SJA1000 目 录摘 要 I Abstract II 第一章 引言 1 1.1 企业现场信息监控系统概述 1 1.2 CAN现场总线 1 第二章 系统整体方案设计及现场信息检测的实现 4 2.1 系统整体结构设计 4 2.2 系统整体设计方案的实现 5 2.3 现场信息检测的实现 6 2.3.1 温度检测电路设计 7 2.3.2 湿度检测电路设计 8 第三章 单片机最小系统设计 10 3.1 ATMega8L单片机简介 10 3.2 LED显示接口技术 13 3.3 报警电路设计 16 3.4 按键电路设计 16 第四章 CAN通信模块设计 18 4.1 CAN通信模块电路设计 18 4.2 CAN通信控制器SJA1000 19 4.2.1 SJA1000内部结构 20 4.2.2 SJA1000的