液体流量标准装置测控系统的研究与设计

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中文摘要

流量标准装置不仅是确定流量仪表计量性能的标准，同时也被广泛用作该类

仪表的实验装置，它的研究和应用在流量计量和检测技术发展领域中是非常重要

的环节。对于流量仪表的设计制造企业，需要为新产品的研制和开发进行大量实

验工作和出厂检定，而对于计量检验部门，需要为流量仪表进行周期性检定测试

和校准，因此流量标准装置不仅须具有足够的准确度和可靠性，同样还应具有较

高的工作效率。

目前国内的静态容积法液体流量标准装置还没有完全实现自动控制，特别是

在测量容器内的液位时，仍然依靠人工目测的方式，因此不仅使得工作效率低下，

而且由于缺乏有效手段来实时监控液位，从而容易出现液体溢出的情况，导致检

定测试必须重新进行，增加了实验人员的工作负担。

为了解决这些问题，本课题针对上海仪器仪表自控系统检验测试所的流量标

准装置，通过采用磁致伸缩液位仪和计算机相结合的控制方式，研究和设计了一

套测控系统，它不仅能够自动采集液位参数，而且以单片机为核心的信息传输设

备可以实时向上位机发送数据，同时还能接收控制指令驱动标准装置上的执行机

构。

由C++ Builder 6.0 开发编写的流量检定测试管理系统程序，拥有内容丰富、

友好的界面，并且操作简单易于使用，可以很好地实现数据处理和逻辑控制等功

能，在结合了由 Access2007 编写的数据库，可以满足使用者查询和打印试验数据

的要求。另外，通过平均值算法，测控程序能够快速判断出容器内的液位稳定值，

缩短了检定时间，提高了试验效率。

基于本文研究设计的测控系统，已经在液体流量标准装置上进行了测试。从

运行情况和试验数据来看，该系统工作正常，实现了自动控制与数据处理功能，

同时经过游标卡尺的校验可知，液位仪的检测性能良好，误差量极小，这为今后

的研究工作中能够使标准装置的准确度等级达到 0.05 级提供了保证。

关键词：液体流量标准装置静态容积法液位测量计算机测控系统

ABSTRACT

Flow standard facilities are some standards for confirming the metrological

performance of flow meters and some experimental facilities extensively used for flow

meters as well. Their development and application is a very important link in the field of

flow measuring and testing technologies. As the designing and manufacturing

enterprises of flow meters need to do large numbers of experiments for the R&D of new

products and the measuring and testing departments of flow meters need to do

verification tests and calibrations for flow meters, it is therefore necessary for flow

standard facilities to be highly accurate and reliable and have high operating efficiencies

as well.

At present, the domestic flow standard facilities used for measuring liquids through

a static volumetric method has not yet realized a thorough automatic control. In

particular, the measurements of the levels of the liquids in containers are still done

through manual visual inspections. As a result, the working efficiencies are low; and the

liquids measured are liable to suffer an overflow phenomenon due to the lack of

effective means for the real-time liquid level detections, thus making it is necessary to

do the verification tests again and increasing the workload of experimental personnel.

In order to solve the problems above, we, according to the characteristics of the

occasions on which measurement quality inspections are done, study in this paper a

control method characterized by a combination of level instruments and SCMs based on

the original facilities and study and design a measurement and control system for the

flow standard facilities of liquids. The measurement and control system can not only

realize an automatic acquisition of liquid level parameters but also sum up and transmit

all the information detected to a host computer. Moreover, it can also drive the actuators

of standard flow facilities to execute control instructions accurately. A host computer

verification test management system program compiled through software C++ Builder

6.0 has friendly interfaces with abundant contents and simple operations and can realize

data display, numerical computation, logic control and some other functions very well.

If used with a database compiled through Access2007, it can also have the historical test

information inquired and printed. The anti-jamming algorithm is capable of judging the

stable liquid level in a container in a short time, thus shorting the verification time and

improving the test efficiency.

The measurement and control system designed based on the studies in this paper

for the flow standard facilities of liquids has entered the stage of commissioning in

Shanghai Inspection and Testing Institute of Instruments and Automation Systems.

Viewed from its operation condition and test data, the system can operate normally and

realize functions of automatic control and data processing. Meanwhile, according to the

results of the verifications done through vernier calipers, the level instruments have

great detection performance and extreme small errors, which provides a guarantee for

the flow standard facilities to reach an accuracy class of 0.05 in the studies in future.

Key word ：Liquids Flow Standard Facilities, Static Volumetric Method, Liquid

Level Measurement, Computer Measuring and Control System

中文摘要

ABSTRACT

第一章绪论 ························································································ 1

§1.1 研究流量标准装置的意义 ······························································ 1

§1.2 流量标准装置检定技术的现状 ·························································2

§1.3 本课题的研究背景及主要内容 ························································ 3

§1.4 本文的创新点 ··············································································4

§1.5 本文的内容和结构 ········································································4

第二章液体流量标准装置的研究 ·····························································6

§2.1 流量计检定技术 ···········································································6

§2.1.1 流量的概念 .......................................................................................................6

§2.1.2 流量的量值传递系统 .......................................................................................6

§2.2 液体流量计检定方法及标准装置介绍 ··············································· 8

§2.2.1 静态质量法装置的结构和工作原理 ...............................................................8

§2.2.2 静态容积法装置的结构和工作原理 ...............................................................9

§2.2.3 标准表法装置的结构和工作原理 .................................................................10

§2.2.4 三种标准装置的比较 .....................................................................................12

§2.3 测控系统运用于流量标准装置的意义 ··············································13

§2.4 静态容积法液体流量标准装置测控系统的提出 ··································13

§2.5 本章小结 ·················································································· 15

第三章液位测量技术 ···········································································16

§3.1 常用液位传感器的工作原理及性能 ·················································16

§3.2 磁致伸缩液位测量技术 ································································ 19

§3.2.1 磁致伸缩液位传感器的特点 .........................................................................20

§3.2.2 磁致伸缩原理 .................................................................................................20

§3.2.3 磁致伸缩液位传感器的结构与工作原理 .....................................................21

§3.3 影响磁致伸缩液位传感器精度的因素 ··············································25

§3.3.1 提高检测时间的分辨率 .................................................................................25

§3.3.2 考虑波速的变化 .............................................................................................26

§3.4 本章小结 ·················································································· 26

第四章计算机测控系统设计 ································································· 27

§4.1 计算机测控系统的组成和功能 ·······················································28

§4.2 计算机测控系统的硬件设计 ·························································· 29

§4.2.1 上位机 .............................................................................................................29

§4.2.2 液位检测系统 .................................................................................................29

§4.2.3 信息传输设备 .................................................................................................30

§4.2.3.1 单片机的选型 ..............................................................................................32

§4.2.3.2 模拟电流信号的采集电路 ..........................................................................33

§4.2.3.3 执行机构的控制电路 ..................................................................................34

§4.2.3.4 串口通信电路 ..............................................................................................35

§4.3 计算机测控系统的软件设计 ·························································· 38

§4.3.1 上位机的软件设计 .........................................................................................38

§4.3.1.1 开发工具的选择 ..........................................................................................38

§4.3.1.2 程序的总体设计 ..........................................................................................39

§4.3.1.3 程序界面的设计 ..........................................................................................39

§4.3.1.4 串口通信的设计 ..........................................................................................42

§4.3.1.5 液位静止判定算法的设计 ..........................................................................43

§4.3.2 单片机的软件设计 .........................................................................................44

§4.3.2.1 开发工具的选择 ..........................................................................................45

§4.3.2.2 串口通信的程序设计 ..................................................................................45

§4.3.2.3 采集模拟信号的程序设计 ..........................................................................47

§4.4 本章小结 ·················································································· 48

第五章测控系统的性能分析和标准装置的检定 ········································· 49

§5.1 液位检测系统的性能分析 ····························································· 49

§5.2 液体流量标准装置的不确定度评定 ·················································50

§5.2.1 计时器的检定 .................................................................................................50

§5.2.2 工作量器的检定 .............................................................................................51

§5.2.3 换向器的检定 .................................................................................................52

§5.2.4 标准装置的不确定度 .....................................................................................54

§5.3 本章小结 ···················································································54

第六章总结与展望 ··············································································55

参考文献 ··························································································· 57

致谢 ································································································· 60

第一章绪论

§1.1 研究流量标准装置的意义

流量计是计量科学技术的组成部分之一，它与国民经济、国防建设、科学研

究以及人民生活各个领域都有着密切的关系，并且是发展工农业生产、保证产品

质量、促进科学技术发展、提高经济效益和管理水平的重要工具。在工业生产自

动化程度愈来愈高的当今时代，特别是随着节能减排、南水北调等国家重点工程

的启动，流量计对推动和支持国民经济的不断发展起到了更加显著的作用。

计量性能是流量仪表的主要质量指标之一，因为它不仅对工矿企业的安全生

产具有很大的意义，而且测量数据还是企业经济核算的重要依据，对于新研制的

或修理后的流量计，必须用适当等级的计量标准来确定它的计量性能是否合格；

对于使用中的流量计，由于磨损、使用不当、维护不良、环境影响或部件内在质

量变化等因素引起计量特性的改变，也必须用计量标准来确定其示值或校准。

由于被测流体的特性复杂，测量条件又各不相同，从而产生了各种不同的测

量方法和测量仪表，如果没有一个统一的检定流量计准确度的方法，那么要保证

大规模生产的工艺要求，以及保证贸易的平等互换将是不可能的。为此，必须建

立复现流量单位量值的标准装置，而流量计量学的另一主要内容就是：研究流量

单位的复现方法和检定系统，以保证量值传递和流量测量的准确度。

由此可见，流量标准装置的研究和应用是流量计与检测技术发展的重要环节，

并且一直受到国内外许多研究机构的重视。随着世界经济的迅猛发展，以及科技

水平的不断提升，流量标准装置的作用也越来越重要，并应用于以下几个方面[1]：

（1）作为流量单位量值的统一与传递的标准，确保我国各地区和各部门的

流量量值能够统一在一个标准值上。

（2）为标准流量计的新型号研制工作提供辅助支持，通过进行测试实验，

可以帮助确定仪表的准确度等级、流量范围和重复性等计量性能，以及它的过载

承受能力、可靠性和寿命等使用特点；另一方面，通过实验还可以研究仪表的动

态特性，以便对仪表进行合理的设计，从而进一步考虑仪表适应的环境条件。

（3）研究流量仪表在理想条件和实际使用条件下的准确度差异，从而采用

合理的介质换算和修正的方法。

（4）在贸易过程中，为交易双方提供权威的仲裁结果。

（5）在制定国家（或企业）的标准和计量检定规程时，研究测试方法并进

行数据的验证。

（6）进行国内外的比对工作，确定系统不确定度，修正量值。

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摘要：

中文摘要流量标准装置不仅是确定流量仪表计量性能的标准，同时也被广泛用作该类仪表的实验装置，它的研究和应用在流量计量和检测技术发展领域中是非常重要的环节。对于流量仪表的设计制造企业，需要为新产品的研制和开发进行大量实验工作和出厂检定，而对于计量检验部门，需要为流量仪表进行周期性检定测试和校准，因此流量标准装置不仅须具有足够的准确度和可靠性，同样还应具有较高的工作效率。目前国内的静态容积法液体流量标准装置还没有完全实现自动控制，特别是在测量容器内的液位时，仍然依靠人工目测的方式，因此不仅使得工作效率低下，而且由于缺乏有效手段来实时监控液位，从而容易出现液体溢出的情况，导致检定测试必须重新进行，增加...

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