定量称重控制仪的设计

定量称重控制仪的设计

摘要

我国的定量称重仪表衡器需求量很大，但定量称重控制仪表技术却相对落后。为此，设计了一种自动定量称重控制仪，该定量称重控制仪具有控制准确度高、功能实用以及性能稳定可靠等特点。本控制仪属于单片机嵌入式系统，采用AT89S52作为系统的MCU 单元。所设计的硬件电路单元主要包括：信号调理电路、数据采集电路、显示和键盘电路、系统输出电路、系统电源电路等。选用了灵敏度高、性能稳定的电阻应变式称重传感器及高分辨率模数转换处理芯片AD7810，保证了系统的测量精度和准确度。通过编制系统的软件程序，实现了三级给料定量称重过程的自动控制、提前量数据的自行修正、包装数据的自动保存以及键盘操作和实时显示等多项实用功能。从而使本定量称重控制仪的稳定性、及定量称重控制的准确度均达到预期的要求。

关键词定量称重；单片机；自动控制

The Design of Quantitative Weigh Control

Instrument

Abstract

The demand for automatic quantitative weighing apparatus in our country is quite large , but the automatic quantitative weighing control instrument technology of our country is still relatively behind the times .So a quantitative weighing control instrument is developed in this dissertation ,and it has the characteristics of high control accuracy ,practical functions and stable and reliable performance etc. This instrument can be classified into embedded microcontroller system, and the microcontroller unit employed in this system is AT89S52.The hardware circuits designed include: data acquisition circuit , display and keyboard circuit , output circuit ,system power supply etc .To ensure the precision and accuracy of the system ,the resistance strain meter type load cell that is of high sensitivity and stable performance and high resolution analog-digital converting chip AD7810 are selected .By programming the software of the system ,several practical functions ,such as the automatic control of three-stage feeding quantitative weighing process, automatic correction of closing lead data ,automatic storage of package data ,keyboard operation and real-time display etc ,are accomplished by the instrument . Experimental tests on stability ,static performance and dynamic performance of the system are conducted respectively .And the analysis of testing reports indicate that the stability and the accuracy and precision of automatic quantitative weighing control of this instrument are in accordance with the desired technical properties .

Keywords：Quantitative Weighing；Microcontroller；Automatic Control

目录

摘要 ............................................................................................................................................................... I Abstract ......................................................................................................................................................... I I 第1章绪论 (1)

1.1 自动定量衡器技术综述 (1)

1.1.1 电子衡器的分类 (1)

1.1.2 自动定量衡器技术国内外发展概况 (1)

1.2 研究本课题的意义 (3)

1.3 本论文完成的主要工作 (4)

第2章系统的总体设计 (5)

2.1 定量称重控制系统的组成和工作原理 (5)

2.1.1 定量称重装置的组成 (5)

2.1.2定量称重控制的工作原理 (6)

2.2 系统的结构方案 (7)

2.2.1系统概述 (7)

2.2.2 系统结构 (7)

2.3 系统的功能、特点及主要技术指标 (8)

第3章系统的硬件设计 (10)

3.1系统硬件的结构 (10)

3.2 微控制器AT89S52及其应用 (10)

3.2.1 AT89S52性能概述 (10)