IJERT-Short Descriptions of Measurements and Instrumentation (original) (raw)
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Measurement techniques have been of immense importance ever since the start of human civilization, when measurements were first needed to regulate the transfer of goods in barter trade to ensure that exchanges were fair. The industrial revolution during the nineteenth century brought about a rapid development of new instruments and measurement techniques to satisfy the needs of industrialized production techniques. Since that time, there has been a large and rapid growth in new industrial technology. This has been particularly evident during the last part of the twentieth century, encouraged by developments in electronics in general and computers in particular. This, in turn, has required a parallel growth in new instruments and measurement techniques. The massive growth in the application of computers to industrial process control and monitoring tasks has spawned a parallel growth in the requirement for instruments to measure, record and control process variables. As modern production techniques dictate working to tighter and tighter accuracy limits, and as economic forces limiting production costs become more severe, so the requirement for instruments to be both accurate and cheap becomes ever harder to satisfy. This latter problem is at the focal point of the research and development efforts of all instrument manufacturers. In the past few years, the most cost-effective means of improving instrument accuracy has been found in many cases to be the inclusion of digital computing power within instruments themselves. These intelligent instruments therefore feature prominently in current instrument manufacturers' catalogues. 1.1 Measurement units The very first measurement units were those used in barter trade to quantify the amounts being exchanged and to establish clear rules about the relative values of different commodities. Such early systems of measurement were based on whatever was available as a measuring unit. For purposes of measuring length, the human torso was a convenient tool, and gave us units of the hand, the foot and the cubit. Although generally adequate for barter trade systems, such measurement units are of course imprecise, varying as they do from one person to the next. Therefore, there has been a progressive movement towards measurement units that are defined much more accurately.
Metrology: Measuring Instruments and Gauges
Book, 2013
Knowledge about anything is complete only when it can be expressed in numbers and something is known about it. Thus, for every kind of quantity measured, there must be a unit to measure it and express it in the numbers of that unit. The unit has to be followed by all, and hence there must be a universal standard. The most important parameter in metrology is length, which can be measured in several forms and in several ways. Measurement plays a vital role in every field of investigation, and present day scientific and technological progress has resulted from progress in the field of measurement.
Lectures on Measurement Science
2005
The epistemic requirement that measurement be an objective and intersubjective evaluation is empirically fulfilled by adopting measuring systems that include selective and repeatable sensors and traceable standards; any measurement is then performed as a (direct or indirect) comparison to a chosen standard. From the instrument output the measurement result has to be inferred by means of a process based on the information gathered from the instrument calibration and a measurement system model. Such a process is only plausible in its results, that must be expressed specifying both a measurand value and its estimated uncertainty. 1.1. Measurement as a comparison model Measurement is an operation of data acquisition and presentation, aimed at expressing in symbolic form the information empirically obtained on a system about a quantity, the measurand (we accept the common ambiguities of calling “measurand” both the system under measurement and the measured quantity, and the latter in bot...
Measuring Instruments and Their Properties 2.1 Types of Measuring Instruments
Measuring instruments are the technical objects that are specially developed for the purpose of measuring specific quantities. A general property of measuring instruments is that their accuracy is known. Measuring instruments are divided into material measures, measuring transducers, indicating instruments, recording instruments, and measuring systems. A material measure is a measuring instrument that reproduces one or more known values of a given quantity. Examples of measures are balance weights, measuring resistors, measuring capacitors, and reference materials. Single-valued measures, multiple-valued measures, and collections of measures are distinguished. Examples of multiple-valued measures are graduated rulers, measuring tapes, resistance boxes, and so on. Multiple-valued measures are further divided into those that reproduce discrete values of the corresponding quantities, such as resistance boxes, and those that continuously reproduce quantities in some range, for example, a measuring capacitor with variable capacitance. Continuous measures are usually less accurate than discrete measures. When measures are used to perform measurements, the measurands are compared with the known quantities reproduced by the measures. The comparison is made by different methods, but so-called comparators are a specific means that are used to compare quantities. A comparator is a measuring device that makes it possible to compare similar quantities and has a known sensitivity. The simplest comparator is the standard equal-armed pan balance. In some cases, quantities are compared without comparators, by experimenters, with the help of their viewing or listening perceptions. For instance, when measuring the length of a body with the help of a ruler, the ruler is placed on the body and the observer fixes visually the graduations of the ruler (or fractions of a graduation) at the corresponding points of the body.
A New Definition of Measurement
Measurement, vol 36, no 1, pp 101-109, 2004
Existing definitions of measurement presented by many scholars in metrology are presented and reviewed. A brief synopsis of advances in thinking about the nature of measurement is also presented. A new definition of measurement is proposed: “Measurement is an empirical process, using an instrument, effecting a rigorous and objective mapping of an observable into a category in a model of the observable that meaningfully distinguishes the manifestation from other possible and distinguishable manifestations.” This definition is discussed in the light of the more recent developments in the conceptualization of measurement.
2015
The 12th comparison between the Swedish National Platinum-Iridium kilogram (Prototype number 40) and the principal kilogram standards for mass has been performed at SP Swedish National Testing and Research Institute. The method used was a weighted least square method with restraint developed by Dr Leslie Pendrill <1>. Weighings for the pan-European key intercomparisons for 1 kg, EUROMET 509 and 510 were made together with the regular kilogram comparison.
A review of the fundamental concepts of measurement
Measurement, 1984
The paper surveys the current state of the theory of the fundamental concepts of measurement which is based on the model theory of logic. A brief review is given of the historical development of measurement theory. The model-theoretic definition of measurement is presented, together with a discussion of representation and uniqueness conditions. Nominal, ordinal, extensive and interval measurement structures are outlined. The classification of scale types and the problem of meaningfulness are considered. A survey is given of conjoint and derived measurement. A brief review is made of the applications of measurement theory. Consideration is given to the treatment of uncertainty. The setting-up of systems of scales of measurement for a domain of science and its relation to theories for that domain are discussed. It is argued that measurement as defined is related to other forms of symbolic representation such as is involved in computer data representation and natural language.