毕业的设计基于CAN总线的远程数据.doc

题 目：基于CAN总线的远程数据 采集系统--下位机部分 基于CAN总线的远程数据采集系统 --下位机部分 摘 要 CAN总线作为一种有效支持分布式控制和实时控制的技术，以其稳定性好、可靠性高、抗干扰能力强、通讯速率高、维护成本低及其独特的设计越来越受到人们的重视，并被公认为是最有前途的现场总线之一。 基于CAN总线的远程数据采集系统分为上位机、CAN总线和下位机三个部分。上位机建立友好的人机交互界面；CAN总线采用总线型拓扑结构，通信电缆采用双绞线；下位机部分是两个传感器节点。 本论文重点介绍了下位机传感器节点的设计。首先介绍了系统总体设计方案，然后对温度传感器节点使用的K型热电偶、温度传感器AD590和压力传感器节点使用的MPX53DP做简要介绍，并分析设计放大电路；接着介绍单片机AT89C52及其附属电路，特别对键盘做了重点分析介绍；分析软件算法，使用C51语言编程；最后介绍系统调试。本设计实现了下位机对现场温度信号和压力信号的采集，通过键盘在线更改测量范围、报警值等参数。 关键词：CAN总线；数据采集；下位机；AT89C52单片机 The Long-distance Data Collection Based on CAN Bus -- The Lower Computer Abstract CAN bus technology, which efficiently supports distributed real-time with a very high level of security, attract attention with a very high level of capability. CAN bus has some advantages such as high level of security, strong anti-interference, high communication speed and low of maintenance cost. It is a particular design, and it is regarded a field-bus with expansibility. The long-distance data collection based on CAN bus is divided into three parts: upper computer and CAN bus and lower computer. The upper computer is established friendly Human-Machine Interface.CAN bus uses bus topology structure, and use UTP cable communications. The lower computer uses two sensor nodes. This paper’s emphasis is to introduce the design of the lower computer sensor node.This design firstly introduced the system overall project design. It introduced briefly the K-thermocouple which uses temperature sensor node, and the MPX53DP which uses temperature sensor AD590 and pressure sensor node.It analyzed the design enlargement electric circuit. It also introduced AT89C52 MCU and its subsidiary circuit, especially focused on analyzing the keyboard.Then it analyzed software algorithm, and used the C51 language for its programming. It introduced the system debugging finally. This design has realized the lower computer to the scene temperature signal and pressure signal collection; through the keyboar