Probabilistic measurement evaluation for the implementation of the Measuring Instrument Directive

The approval of the European Measuring Instrument Directive (2004) constitutes a noteworthy novelty in legal metrology, since this Directive implements the so called “new approach” to technical normalization and harmonization and moves toward a “global approach” to evaluation and conformity. According to the principles of the new approach regulatory model, the Directive establishes some essential requirements for a wide class of measuring devices, subject to legal control, whilst leaving manufacturer free to develop proper technical solutions for meeting them. Moreover, the conformity of instruments to prescribed requirement may now be ensured through quality assurance procedures, in the context of a quality system. This increase in technical and metrological freedom on the manufactures side may promote innovation, social benefit and costumers’ satisfaction, provided that some recent advances in measurement theory are properly employed.In this paper, after a brief discussion regarding the philosophy of the Directive, a probabilistic approach to conformity assessment is presented. The proposed approach concerns some currently open issues such as measurement uncertainty due to the influence of operating conditions, the assessment and reduction of the risk related to measurement uncertainty in conformity decision and the costs of instrument uncertainty and of non-conformity, for both the manufacturer and the user. The approach is supported by a package of software codes that assists the application of verification procedures, with a user-friendly approach.All these aspects are discussed with reference to the case of water meters, considering both end-of-production acceptance tests and the performance of meters under operation.     

Electrical energy metering: Some challenges of the European Directive on Measuring Instruments (MID)

The introduction of static electric energy meter together with voltage and current distortions in the electric networks are revolutionizing the measurement of the electrical energy. Several questions and studies are proposed in the scientific literature concerning with metrological and reliability aspects of the actual electrical energy measurement. The European Directive on Measuring Instruments (MID) represents a different spin on setting the performance and safety requirements for those meters. The International Organization of Legal Metrology (OIML) has published the document D11 discussing recommendations for legislation to meet the MID. An OIML technical committee is drafting the recommendation (IR46) that would give regulatory bodies an easily-adoptable set of requirements and tests to meet the requirements of the MID. With the introduction of the MID directive, the actual discussion involves aspects as the metrological characterization of the meters. The paper proposes an analysis of the test settings imposed by the actual MID-harmonized standards, regarding the electric energy metering. The aim is to check the presence of degree of freedom in the test settings that could compromise both result reliability and the compliance/non-compliance of a given apparatus.     

Some statistical aspects of binary measuring systems

Qualitative analysis is often used to determine whether or not a particular feature appears or is absent in tests, in quality control procedures, identification scans, go/no go measurements and many other fields. Generally, such analysis uses simple measuring methods that classify the analyzed property value into two comprehensive and exclusive classes/categories. The performance reliability of such binary measurement systems (BMSs) is usually assessed by false positive and false negative rates. The article presents some additional aspects related to metrological properties of BMS: traceability – described in terms of sequential hierarchical chain of consecutive BMSs calibrations – error accumulation, distribution of test results, consistency and repeatability problems. It is shown that some intuitively plausible at a first glance concepts such as hypotheses about the binomial distribution of test results or consistency testing by sequentially repeated sorting are wrong if the objective is to conduct a deep examination, and therefore, should be avoided.     

Multisensor data fusion via Gaussian process models for dimensional and geometric verification

An increasing amount of commercial measurement instruments implementing a wide range of measurement technologies is rapidly becoming available for dimensional and geometric verification. Multiple solutions are often acquired within the shop-floor with the aim of providing alternatives to cover a wider array of measurement needs, thus overcoming the limitations of individual instruments and technologies.In such scenarios, multisensor data fusion aims at going one step further by seeking original and different ways to analyze and combine multiple measurement datasets taken from the same measurand, in order to produce synergistic effects and ultimately obtain overall better measurement results.In this work an original approach to multisensor data fusion is presented, based on the development of Gaussian process models (the technique also known as kriging), starting from point sets acquired from multiple instruments. The approach is illustrated and validated through the application to a simulated test case and two real-life industrial metrology scenarios involving structured light scanners and coordinate measurement machines.The results show that not only the proposed approach allows for obtaining final measurement results whose metrological quality transcends that of the original single-sensor datasets, but also it allows to better characterize metrological performance and potential sources of measurement error originated from within each individual sensor.     

关于散装水泥料罐秤计量检定方法的探讨

水泥生产企业用于对散装水泥专用运输船舶进行计量的散装水泥料罐秤,由于罐体直径和高度均达数十米、最大储存一般在数百吨,无法放置大质量砝码,因此,计量检定十分困难;加之有些水泥生产企业,计量法律、法规意识薄弱,计量检定登记受检率相当低,其计量性能无法确保准确,水泥生产企业和消费企业由此引起的经济纠纷时有发生。为改变这一状况,本人所在的计量技术机构对此进行了探索,运用替代法,进行散装水泥料罐秤的静态计量检定,取得了一定的经验,在此抛砖引玉,旨在对计量检定同行和有关企业有所启迪。     

Metrological reliability in measurement

The presentation of the main results attained today in the field of metrological reliability must be preceded by isolating some principal problems. The first concerns the reliability of measurements and the reliability of measuring instruments, while the second concerns the definition of the metrological failure. The third problem is to do with the classification of characteristics of the metrological reliability.The paper will discuss that part of the metrological reliability which deals with the hardware, that is, with instrumental reliability. Basic models used in metrological reliability will be evaluated. A relevant aim of the paper is to describe the present state and to express some new ideas about the future development of metrological reliability.     

电子皮带秤示值误差测量不确定度分析

随着韶钢铁前计量管理系统的正式运行,担负着铁前各单位工序之间物料输送计量用的电子皮带秤,在各单位成本核算,降低能源消耗,提高经济效益的需要作用日益主要。为此,对承担煤炭、焦炭、烧结矿等物料输送计量的电子皮带秤的计量性能提出了更高的要求,本文在对电子皮带秤进行计量检定,判断是否符合国家计量检定规程的要求之外,试对其计量检定过程中不确定度来源进行分析,从定量的角度分析计量皮带秤的计量性能。     

条码技术在气象计量检定管理中的应用

条码技术已成为全球应用广泛的信息自动识别技术之一,它作为信息的另一种表述形式,是实现文件、档案等信息的存储、携带、传递并识读的理想手段,将之引入计量检定管理中,可以有效地提高计量检定的管理水平和效率。文章介绍了条形码技术在气象计量检定管理中的应用,对其技术细节和具体实现过程进行了详细的描述。     

力学计量仪器检定应注意的问题及措施分析

力学计量仪器的检定是一项十分严格的过程,主要是对力的值、质量、推动频率等一系列的计量测试。由于力学计量仪器种类繁多,所以在进行仪器使用时,要严格遵循计量标准的相关规则进行实施,严格按照实际注意事项选择合理力学计量仪器规格、性能。本文首先提出力学计量仪器检定应注意问题,并以压力表、内燃机等为例,提出加大细节检验等策略,希望对力学计量仪器鉴定工作有所借鉴。     

Metrological self-check and evolution of metrology

There are growing indications of a crisis in conventional methods of metrological assurance for measuring instruments with built-in self-checking. This paper offers an analysis, looking in the first instance at sensors. An analogy between biological and technical evolution is discussed. It is argued that the future will see intelligent sensors and measuring systems being mass produced with inbuilt metrological self-checking, as well as the transition to a new stage in the evolution of metrological assurance of sensors.     

省级检定业务风洞流场特性研究

针对甘肃省气象计量检定站改造后的HDF-500直流低速风洞,对其流场特性进行研究.通过对风洞试验段内气流流速的测量结果计算和分析,表明该风洞的试验段风速与变频器频率呈线性关系,且气流流速范围达到改造的要求.改造后风洞的气流稳定性、均匀性、气流偏角和噪音均符合性能要求,具备开展检定业务的基本条件.     

T/CSAE 178—2021《电动汽车高压连接器技术条件》 标准解读

T/CSAE 178—2021《电动汽车高压连接器技术条件》 标准规定了电动汽车高压连接器的定义、 性能要求以及试验方法,并推荐连接器的典型安装界面,该标准适用于符合GB 18384规定的B级电压的电动汽车高压连接器.主要简述T/CSAE 178—2021标准编制的背景,并对技术条款进行了详细解析;介绍了各项技术要求的...     

火力发电厂在线化学仪表存在的主要问题分析及改进方向

介绍了火力发电厂水汽循环系统在线化学仪表的主要类别,并分析了各类仪表测量误差的常见原因。通过对各电厂在线化学仪表的检测,指出各电厂在线化学仪表计量管理工作中存在的主要问题,并提出了在线化学仪表管理工作的改进方向。     

Simple method to determine linearity deviations of topography measuring instruments with a large range axial scanning system

The use of areal characterization of surface texture with high accuracy in a quality control process requires reliability. Therefore, regular inspection of the measurement systems is needed. Important metrological features of a measurement system in dimensional metrology are the amplification factor and linearity.This paper presents a simple method for characterizing the axial scanning system of areal topography measuring instruments with little expense and effort, well suited for industrial routine calibration in the field. The method is based on employing a single material measure with a range of step heights. It is shown that the amplification factor and linearity deviations can be determined and adjusted for large axial measurement ranges.     

高压试验测试设备数字式校验系统的研制

研制的高压试验测试设备数字式校验系统主要针对交、直流数字高压表和分压器的校验工作,目的是提升校验工作的自动化程度和数据质量。介绍了校验系统的工作原理和核心技术,该系统是基于智能化仪器仪表、GPIB通信、同步触发、数据处理等技术实现的。经法定计量检定机构提供的试验数据,该装置性能参数达到设计要求。     

计量器具是技术作弊的原因分析及防范措施

本文主要从技术视角下分析计量器具是作弊违法现象高发主要是由于对计量器具的理解和认识滞后,技术评价重计量性能、轻防作弊要求和强制检定执行机构技术力量不足的原因所引起,针对这些原因,提出了相应加强计量器具是防止作弊违法的对策。     

时统通讯系统计量保障方案研究

提出时统通讯系统计量保障系统的设计方法和保障方案。时统通讯系统是武器鉴定试验的重要关键组成部分,其可靠性、准确性直接影响武器鉴定试验的结果。时统通讯系统的基准频标在长时间的使用过程中会出现准确度的偏移等其他性能的改变,要确保其武器鉴定试验阶段的工作状态在技术指标要求的范围内,必须对基准频标进行定期的和试验前的计量检定。文中对计量保障的方案、方法进行了研究,分析了各＂1＂75法的适用性和保障时间周期。     

大口径光学系统的镜面视宁度检测

为了保证大口径光学镜面加工检测的质量和效率,提出了提高大口径光学系统镜面视宁度检测精度的方法。利用电子自准直仪以及平面镜确定波前斜率,推导了基于斜率信息与镜面视宁度之间的关系。为了提高测量精度,突破单台自准直仪精度限制,采用三台自准直仪进行互标校。为了进一步降低误差,使用六自由度平台支撑立方反射体,使精度提高至0.01″量级。另外,结合频响函数的相关理论,估计得到了六自由度平台在检测环境下所引入的误差。最后,引入标准化点源敏感性(PSSn)对结果进行评价,并开展了数值仿真实验。针对模拟镜面视宁度,分别计算两个方向的斜率功率谱以及原始波前功率谱,然后利用之前给出的功率谱与PSSn之间的关系得到了两个方向的PSSn均为0.999。该镜面视宁度测量方法可以在模拟望远镜实际工况下,完成对于系统主镜视宁度的定量预测。     

Measurement and control of surface finish in manufacture

The topography of technical surfaces and the reasons for their assessment in the fields of process control and precision engineering are reviewed. Alternative approaches to surface characterization and the range of instrumentation currently available for measuring surface texture are discussed. Particular reference is made to digital profiling instruments based on microprocessors and to the extended range of parameters these instruments can provide. Throughout, discussion is linked to the contents of Australian Standard AS2536     

Standardizing the metrological assessment of waveform digitizers: problems and perspectives

The problem of the metrological qualification of data acquisition systems and of waveform recorders is a fundamental issue for both users and manufacturers of digital instruments. The need for an improved industry standard leading to unification and standardization in this field is a very pressing requirement. Users have to receive technical specifications written in standard format and manufacturers have to obtain this information following standard test procedures. The main goal of this paper is to underline the need of unifying the modeling, identification and optimization of ADC-based systems, by minimizing the number of experimental procedures to be employed. This work, more than giving solutions, is intended to state clearly a set of problems that we hope will gain the attention of researchers in this field.