基于单片机的包装称重系统的研究与设计(附总电路图,程序清单)

基于单片机的包装称重系统的研究与设计(附总电路图,程序清单)(任务书,开题报告,论文12000字)
摘  要
本论文在分析了国内外称重技术发展的基础上，着重对一个用于工业控制且功能较齐全的自动称重系统进行设计。随着自动化和管理现代化的进展，自动在线称重，快速动态称重在整个称重系统中有了很大的发展。因此，进一步采用新技术，开发各种自动称重系统和提高称重的准确度已经成为了多数国家科技发展的重中之重。
本称重系统除了有关于数据的收集，处理，运行和通信之外，还有更多的其他辅助功能：自动称重系统除了能够储存数据资料到资料库中，还可以将资料以打印稿的形式呈现。最重要的是，该自动称重系统还可以随时对资料库进行访问和查询。
本论文所设计的自动称重系统是应用于工业上的物料包装自动称重的，它的实现有两个过程，第一阶段由异步电机带动粗螺旋推进器给料，这一阶段可看成为粗调过程，给料重量一定要小于额定重量。第二阶段由步进电机带动细螺旋推进器进料，可看成是微调过程，使实际重量等于要求的额定重量。
本称重系统采用单片机AT89C51为控制核心，实现称重仪的基本控制功能。系统的硬件部分包括数据采集和数据处理两大部分，其中数据采集部分由称重仪模拟器、信号的前级处理（采用仪表放大器INA121）和 双积分A/D 转换部分组成。由于称重仪设计中电路的精度及抗工频干扰能力要求较高，故选用精度较高的仪表放大器INA121和抗工频干扰能力较强的双积分A/D转换器MC14433。
 本系统通过应用传感器，各种芯片及单片机使得该称重系统的实际操作性更强，便于应用于工业上。

关键词： AT89C51单片机；双积分A/D转换；仪表放大；数据采集
 
Abstract
Basis on the researching of the progress of the weighing technology, this paper introduces the development of automatic weighing system which has a complete function.
With the progress of automation in industry and modernization in management, there is much progress in weighing online, fast and dynamic weighing and system of weighing.Adopting newer technology, developing diversified automatic weighing system, improving accuracy and enhancing network function are emphasized in every country nowadays. .
Besides the function of collecting, processing, displaying and communication of data about weight, the automatic weighing system can also save data in database and print data in report form. It can also visit and query the records in database.
The article introduced the automatic named weighing system which is applied in the industry, its realization has two processes, the first stage is the spiral propeller by the asynchronous machine belt to afford the material, this age which is worthy of looking at is because of the coarse adjustment process,certainly it must be smaller than the schedule weight for the material weight. The second stage is impetus which is much more precise than the first spiral propeller feeding, it may be regarded as the special process. This system has been applied in the sensor, each kind of chips and monolithic integrated circuits.
This system is based on single chip AT89C51, it can make electronic scale's basic control function come true. System's hardware includes smallest system board and the acquisition of data. The smallest system part mainly realizes the demonstration of  the diodes and the control of keyboard ,the part of data’s acquisition is consists of the simulator of weighing meter , signal level processing (amplifier INA121) and the fraction of the double integral A/D conversion . Because of the high request in precision of the electric circuit of the weighing meter design and the ability of anti-power frequency disturbance, the selection of the high precision appliance such as the amplifier INA121 and double integral A/D switch MC14433.
The system would be stronger by using different elements,and it would have better performance in application of the industry.

Key words： AT89C51 single chip;double integral A/D transformation; measuring appliance enlargement;  collection of data
 

目  录
第1章 绪论    1
1.1 引言    1
1.2 研究背景    1
1.2.1 国内外的发展与研究现状    1
1.2.2 未来发展趋势    2
1.3 电子称重系统的组成    3
1.3.1称重传感器    3
1.3.2称重仪表    3
1.3.3承载器    4
1.4研究的目的及意义    4
第2章 主要元器件选型    6
2.1 主控芯片选择    6
2.2 转换电路芯片选择    7
2.3 仪表放大器选择    8
2.4 电源选择    10
2.5 显示模块选择    10
2.6 本章小结    10
第3章 硬件系统的设计    11
3.1电路总体原理框图设计    11
3.2 主芯片引脚应用    11
3.3 转换模块    14
3.4 前级放大模块    15
3.5 自动称重模块    16
3.6 显示模块    16
3.7 本章小结    18
第4章 软件系统的设计    19
4.1主程序模块    19
4.2子程序模块    20
4.3 中断程序模块    21
4.3.1 T0中断程序    21
4.3.2 T1中断子程序    21
4.4 调零程序模块    21
4.5 显示重量程序模块    22
4.6退出程序模块    23
4.7显示总数程序模块    24
4.8 本章小结    24
第5章 结论    25
参 考 文 献    26
致  谢    27
附录A  设计总电路图...........................................................................................................I
附录B  程序    II