单片机控制的直流毫伏表设计

单片机控制的直流毫伏表设计

文档编号:JD1061 文档字数:22037,页数:50

摘要：直流毫伏表是针对毫伏级微小信号的精确测量,应用于实验检测、生产检测及维修使用等。其中，直流毫伏表常被用在实验检测中，用来测量热电偶、热电阻等敏感元件的小信号的检测。
随着工业技术的进步,由单片机控制的直流毫伏表已经广泛地应用到各行各业中去,功能更加多样，使用更加方便、可靠，而且准确度大为提高，并可测量直流电压、电流及电阻。特别是随着微计算机技术的迅猛发展，电子计算机从过去的庞然大物已经可以缩小到可以置于测量仪器之中，作为仪表的控制器、存储器及运算器，并使其具有智能作用。直流毫伏表是常用的测量仪器，采用数字方式可以使操控更直观，而且反应速度快，是理想的毫伏范围测量工具。
本文阐述了系统的结构和工作原理，搭建了直流毫伏表的硬件电路，并设计了软件系统中的数据采集处理和显示部分的程序。硬件电路主要由信号放大电路、A/D转换、单片机和显示部分组成,软件设计主要是对数据采集、处理和显示方面的编程。整个系统运行过程完成如下操作,即来自信号源输出的毫伏级电压信号经过放大单元后进行A/D转换,经单片机进行数据采集、处理后，然后通过键盘显示接口芯片控制、译码驱动送LED显示器显示。
文中的数据显示系统是以单片机AT89C52为核心，输入信号经过信号调理电路调理，送入A/D转换芯片，再由单片机进行数据采集和处理，最后通过键盘显示接口芯片HD7279A将测量结果显示在LED显示器上。
本系统软件在快速应用程序开发环境Keil C51下编制。程序调试结果表明，程序设计方案是可行的，实现了数据采集处理显示的功能，具有较好的实时性和可靠性，有一定的实用价值和前景。

关键字:直流毫伏表；显示仪；单片机；数据采集与处理

Abstract

DC millivolt millivolt level table for the accurate measurement of small signals, Used in experimental testing, production testing and maintenance of the use of. Among them, the DC millivolt table testing is often used in the experiment, the thermocouples used to measure the thermal resistance of such sensitive components of the small-signal detection.
With the industrial and technological progress, by the DC-mV single-chip control table has been broadly applied to all walks of life, and More diverse functions, the use of more convenient, reliable, and much higher accuracy, And measuring DC voltage, current and resistance. In particular, micro-computer technology with the rapid development of computer giant from the past can be reduced to measuring instruments can be placed, and as the instrument controller, memory and computing devices, and its role with intelligence. DC millivolt table is commonly used measuring instruments, the use of digital manipulation can make a more intuitive, and fast response, is an ideal measurement tool millivolt range.
This paper describes the system structure and working principle, to build a DC mV meter hardware and software system design of data acquisition and processing and display part of the process. Hardware circuit by signal amplification circuit, A / D converter, microcontroller and display components, software design is the data acquisition, processing and display programming. The entire system following the completion of the process operation, that is, the output from the signal source of the mV-level voltage signal after amplification module for A / D conversion, carried out by the single-chip data acquisition, processing, and then through a keyboard display interface chip control, translation Code to send LED display driver.
Weighing system which is described by this article is centers on singlechip AT89C52. The amount of material is sensed by weighing sensor, adjusted by signal adjusting circuit, sent to AD conversionv card, then data collection and deal with by computer. Finally the result will be display by LED with the help of keyboard display interface CMOS chip HD7279
The system software is based on developed under rapid application development environment Keil C51. Experimental results indicate that the design of this system is feasible, and the system not only has good real-time characteristic and reliability, but also has practical value and popularizing prospect.

Key word: DC mV Table; Display instruments; Single-chip data; Processing and collection

目录

摘要 I
Abstract II
1 课题内容及总体设计方案 3
1.1 课题主要内容 3
1.2 课题研究方案 3
2 直流毫伏表的硬件电路 4
2.1 单片机的种类 4
2.2 信号放大的作用及其重要指标 4
2.3 A/D转换及其重要指标 6
2.4 信号处理与通讯 7
2.5 系统存储器扩展 7
2.6 LED显示的原理 8
2.7 复位电路的设计 9
2.8 单片机与PC机接口电路 10
3 软件开发工具的介绍 11
3.1软件开发工具的介绍 11
3.1.1 项目管理 11
3.1.2 集成功能 11
3.1.3 C51 工具包的安装 12
3.1.4 Keil C51 工具包各部分功能及使用简介 12
4 主程序流程与编程思想 14
5 数据采集与处理部分的程序设计 16
5.1　MAX132 AD转换芯片的引脚功能与编程 17
5.2 MAX132 AD转换芯片串行协议 18
5.2.1 读写串行数据的编程 19
5.2.2 命令输入寄存器0的编程思想 20
5.2.3 命令输入寄存器1的编程思想 22
5.2.4 输出寄存器的编程思想 22
5.2.5 冲突位警告微处理器 23
5.3 MAX132 AD 延时程序的设计 23
5.4 结果输出与数据处理程序 25
6 数码管显示部分的程序设计 27
6.2 HD7279A引脚功能与编程 27
6.3 HD7279A的数据接收程序 29
6.4数码管控制部分的编程 32
6.4.1 HD7279A方式0译码及其编程 32
6.4.2 HD7279A方式1译码及其编程 33
6.4.3 HD7279A方式２译码及其编程 34
7 AT89C52单片机的功能 35
7.1 AT89C52的性能简介 35
7.2 单片机的存储器 38
7.2.1 数据存储器 38
7.2.2 程序存储器 39
7.2.3 特殊功能寄存器 39
7.3 定时器 39
7.4 AT789C52在直流毫伏表中的应用 40
8 直流毫伏表的工作过程 41
9 结论 42
10 致谢 43
11 参考文献 44

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