基于rs-数据采集系统下位机设计.docx

基于RS-485总线的数据采集系统下位机软硬件设计摘要轮对压力机作为机务检修中的重要组成部分，其在整个检修过程中起着不可忽视的作用。现当今，诸多机务检修期间，多采用简单的人工或半自动压力数据采集，导致精度不高而且进展缓慢。随着电子技术和微型计算机的推广，微机测量和控制技术得到了迅速地发展。单片机因其具有处理能力强、运行速度快、功耗低等优点，从而在数据采集与控制方面得到了广泛的应用。基于这种局面，所以做出对轮对压力的数据采集系统的设计。本文详细阐述了基于RS485总线的数据采集系统下位机软硬件的设计。硬件设计中以AT89C51单片机为控制核心，采用PPM226-LS2-2型压力传感器进行压力的检测，使用ADS7824进行A/D转换，从而实现轮对压力数据的采集；并辅以DS1302实现时间数据的采集，采用MAX485芯片实现TTL电平的转换，从而实现与上位机（即PC机）的串行通信。在本系统的设计中，程序设计采用了C51编程语言，其主要包括数据采集模块，时间提取模块。关键词：数据采集；AT89C51；ADS7824；DS1302；MAX485The software and hardware design of Data acquisition system based on RS-485 bus computer ABSTRACTAs the most important part of the locomotive maintenance, the wheel press plays an innegligible aspect in whole process of the maintenance. Nowdays the use of simple artificial or semi-automatic pressure data collection have an negative influence in the accuracy of measurement .As the electronic technology and microcomputer promotion, computer measurement and control technology get the quick development. SCM processing power because of its strong, fast and low power consumption advantages, thus in the data acquisition and control in a wide range of applications.Based on this kind of situation, the design of system of pressure date of wheel appears.This Thesis put eyes on the design of the hardware of data acquisition system based on RS485 bus. To achieve date of pressure, The design of hardware ,in which AT89C51 is its core part ,include not only PPM226-LS2-2 to acquisition date of pressure but also ADS7824 to transform between analogy imformation and digital imformation , this system use DS1302 to attain date of time, and use MAX485 chip to realize Level conversion,In this system the design of software ,the program ,which are realized by language of c51,include Data acquisition modules and Timing extraction module.Key Word：Data Acquisition; AT89C51; ADS7824; DS1302; MAX485目录1 绪论11.1 小型集散测控系统现状11.2 课题研究背景及任务11.3 本设计的主要结构与内容12 数据采集系统下位机总体设计方案32.1 设计思路32.2 系统网络结构框图33 系统硬件电路设计53.1 AT89C51介绍53.1.1 AT89CXX系列