发布时间：2015-01-21 来源：人大经济论坛

自动化专业论文范文 目 录 摘 要Ⅱ AbstractⅢ 目 录Ⅳ 1 绪论1 1.1 电子称重技术的现状1 1.2 电子称重技术的发展趋势1 1.3 项目研究背景3 1.4 本文的主要工作4 2 系统方案论证与选型5 2.1 控制器部分5 2.2 数据采集部分6 2.1.1 传感器的选择6 2.2.2 放大电路选择9 2.2.3 键盘处理部分方案论证13 2.3 显示电路部分的选择13 2.4 超量程报警部分选择13 2.5 通讯接口部分方案论证13 3 系统硬件电路设计15 3.1 STC12C5A16S2的最小系统电路15 3.1.1 STC12C5A16S2单片机介绍15 3.1.2 单片机管脚说明17 3.1.3 STC12C5A16S2的最小系统构成19 3.2 数据采集部分电路设计19 3.2.1 传感器和其放大电路与STC12C5A16S2单片机接口电路设计19 3.2.2 测量算法20 3.3 键盘输入电路与STC12C5A16S2单片机接口电路设计21 3.4 LED显示电路与STC12C5A16S2单片机接口电路设计22 3.4.1 LED显示器结构与原理22 3.4.2 LED显示器与显示方式22 3.5 变平器与STC12C5A16S2单片机接口电路设计23 3.5.1 RS-232C机械连接器及引脚定义23 3.5.2 RS-232电平转换芯片及电路24 4 系统软件设计26 4.1 系统主程序26 4.2 键盘管理模块27 4.3 数据处理模块29 4.4 计价模块29 4.5 上位机通讯30 4.5.1 MSComm控件的使用30 4.5.2 通讯过程31 5 系统调试与分析32 5.1 调试系统简介32 5.2 调试故障及原因分析32 6 结 论32 6.1 主要工作成果33 6.2 存在的不足34 致 谢35 参考文献36 附录37 摘 要 现代社会的发展，对称重系统提出了更高的要求。目前，台式电子秤在商业贸易中的使用已相当普遍，但存在一定的局限性，虽然在体积，成本控制方面有所改进，但需要工频交流电源供应、携带不便、应用场所受到制约，且随着信息技术的发展，某些领域人们需要对所得数据进行处理，期待测量更准确、价格更低廉且具有与PC机相连功能的电子秤投放市场。 本文设计的电子秤以STC单片机为主要部件 ，用C语言进行软件设计，硬件则以全桥传感器FAB-80为主，量程为0~10kg，随时可改变上限阈值，并达到阈值报警的功能。在文中论述了称重系统的工作原理，给出了系统电路设计与软件流程，进行实物制作并调试。 本文设计的基于单片机的电子称重系统主要由电源、称重传感器、单片机、键盘/开关、LED显示器,串口通信等构成智能称重系统电路板，从而实现自动称重系统的各种控制功能。可以说,此设计所完成的电子秤很大程度上满足了应用需求。 关键词: 串口通信; 称重传感器;STC 单片机; LED显示器；FAB-80 The development of the modern society has put forward higher request on weighing technology. The desk-top electronic scales have been great application in commercial trade, but they have many shortcomings such as large volume, high cost, AC supplypower and not covenience to carry, so they are restricted to use. And with the development of information technology, some areas that people need to process the data So they have been expecting cheap portable electronic scales which can measure accurately and nd has the function of PC-linked electronic scale on the market. This electronic scale designed to take STC microcontroller as the main components, with using C language to Compile software in the thesis. And the hardware is based by full-bridge sensors FAB-80, its range is 0 ~ 10 Kilogram. Limited threshold value can be changed at any time to reach the alarm threshold function. The thesis discusses the working principle of weighing system, giving circuit design and software process and making physical production with debugging. The microcontroller-based electronic weighing system consists of power supply, load cell, microcontroller, keyboard / switch, LED display, serial communications. All of them constitue an intelligent weighing systems board to achieve a variety of control functions of automatic weighing system. It can be said that the completion of the design of electronic scale meets the application requirements to a large extent. Keywords: serial communication; load cell; STC microcontroller; LED display; FAB-80