摘   要

隨著微電子技術(shù)的發(fā)展，現(xiàn)場總線技術(shù)日益成為國內(nèi)外儀表界的關(guān)注焦點。CAN現(xiàn)場總線作為一種有效支持分布式控制和實時控制的技術(shù)，越來越受到人們的重視，并被公認為最有前途的現(xiàn)場總線之一。
本文在分析論述了現(xiàn)場總線技術(shù)的有關(guān)性能特點及CAN協(xié)議規(guī)范后，就開發(fā)CAN現(xiàn)場總線系統(tǒng)的有關(guān)技術(shù)作了分析和研究，以此為基礎(chǔ)，在硬件上完成了以PIC單片機為核心的溫濕度數(shù)據(jù)的采集、溫濕度數(shù)據(jù)的實時顯示及存儲、時鐘控制，并用CAN總線組網(wǎng)構(gòu)成分布式溫濕度測量系統(tǒng)。
做為分布式測量系統(tǒng)中的一個節(jié)點來說，軟件實現(xiàn)的功能有系統(tǒng)的初始化、溫濕度數(shù)據(jù)的采集及處理、數(shù)據(jù)的存貯、鍵盤的控制、實時顯示、定時采集、通過CAN接口的遠程數(shù)據(jù)通信功能、系統(tǒng)的安全可靠性設(shè)計等。
本設(shè)計的分布式測量系統(tǒng)具有通信可靠、節(jié)點硬件設(shè)計簡單、溫濕度測量精度高、功能強大、造價低等優(yōu)點，因此廣泛地適用于各行各業(yè)需要溫濕度測量的場合。
 
關(guān)鍵詞  CAN總線  PIC16F877  SJA1000  82C250

Abstract 

With the appearance and development of the microelectric technique, the technology of the on-the-spot bus becomes the focus paid close attention by domestic and international instrument circle day by day. The on-the-spot bus of CAN is as a kind of technology of supporting distributed controlling and real-time control effectively, paid attention to more and more by people, and is recognized as one of the most promising on-the-spot buses. This text, after analysing and describing the relevant performance characteristic of the technology of the on-the-spot bus and CAN agreement norm, have done analysis and studied in relevant technology of developing CAN on-the-spot bus system, based on this, is it regard PIC one-chip computer as core form temperature and humidity survey instrument, form location sampling, many sets of the next temperature and humidity monitoring system of machine at the one with CAN bus group network to finish at hardware.
Realize PC through CAN bus to regard PIC as instrument that core form realize long-range management , long-range control , long-range configuration , long-range function of correcting etc. at software. Through is it indicate based on on-the-spot bus instrument of CAN agreement stability, real-time character, other have an advantage over traditional instrument to run actually.

Key words  CANBUS 　  PIC16F877   SJA1000    82C250

目  錄

摘   要 I
Abstract II

第1章  緒論 1
1.1研究背景和意義 1
1.2 CAN現(xiàn)場總線的技術(shù)特點 3
1.3 CAN現(xiàn)場總線的工作原理 4
1.4 CAN現(xiàn)場總線與其他總線的比較 5
1.5 基于CAN總線的分布式測量系統(tǒng)構(gòu)成 7
第2章 CAN總線節(jié)點的硬件設(shè)計 9
2.1主要元器件的選擇 9
2.1.1傳感器的選擇 9
2.1.2單片機的選擇 13
2.1.3 CAN總線控制器的選擇 14
2.2 儀表硬件設(shè)計 23
2.2.1主控電路設(shè)計 23
2.2.2 液晶顯示部分 23
2.2.3 3×3鍵盤部分設(shè)計 26
2.2.4 CAN總線接口電路設(shè)計 27
2.2.5 電源部分設(shè)計 28
2.2.6 存儲器及時鐘芯片電路設(shè)計 29
第3章 測量系統(tǒng)軟件設(shè)計 33
3.1節(jié)點總體軟件設(shè)計 33
3.2節(jié)點液晶顯示子程序設(shè)計 34
3.3 節(jié)點鍵盤接口子程序設(shè)計 35
3.4節(jié)點CAN通信軟件設(shè)計 39
3.5節(jié)點數(shù)據(jù)采集軟件設(shè)計 46
3.6上位機軟件設(shè)計 47
第4章 儀表可靠性的設(shè)計 50
4.1數(shù)據(jù)采集系統(tǒng)中的抗干擾設(shè)計 50
4.1.1地線設(shè)計 51
4.1.2印刷電路板的尺寸與器件布置 52
4.1.3 電源線布置 52
本設(shè)計經(jīng)濟與社會效益分析 52
結(jié)論 53
致謝 54
參考文獻 55
附 錄1 57
附 錄2 58
附 錄3 65
附 錄4 73