Measurement: types of measurement. Types of measurements, classification, errors, methods and means

The term "measure" refers to the evaluation of something. Within the framework of metrology, this word has two different meanings. In the first case, we mean the creation of a designation for a unit. In the second, the measure is necessary in order to reproduce the unit value of the parameter.

General information

An indicator of a physical quantity is the means necessary for the measurement. It is used to reproduce and store the specified physical units. This includes, for example, weight or measuring resistance. Throughout the world, there is a single definition for the notion of "metrology." This is a branch of science that studies the dimensions, the methodology of their unification, and the rules for obtaining the required level of accuracy. The term "metrology" is derived from the words of the Greek language, which together mean "studying measures."

Unity of measurements

There are certain rules for recording, in which indicators are recorded in units accepted by law. However, for the errors of results there are limits. In this framework, the indicators are considered acceptable. Therefore, various types of measurement errors are created, which differ in the degree of deviation. The main task of the recording rules is the transformation of all results obtained at different points, at different times, using different instruments and methods, into a single system. In our time, it is necessary to obtain more accurate and reliable data in the fields of science and economics. Therefore, the types of measurements are intensively studied. Metrology is of great importance.

Measurement. Types of measurement

There are various interacting operations whose task is to establish the types of relations between the value that is evaluated and the one that is considered a unit. The latter is fixed in the measuring device. A numerical value is the data received. They have another name - an indicator of physical magnitude. There are different types of measuring instruments. These include the units themselves, and instruments, and special converters, as well as systems and installations. Vast meaning of the concept of "dimension". The types of measurement are also very diverse. However, there are some common points. Types and methods of measurement are united by one structure. Evaluation procedures consist of two stages. First of all, you need to compare the measured value with the reference unit, and then convert to the desired format, referring to a certain method.

Variationality

Not only are the types of measurements different. Classification of devices for carrying out this procedure also assumes the existence of different sections. The systematization by appointment, for example. One group of devices is called exemplary, and the other group is called workers. The former are necessary in order to use them as a standard for checking the accuracy of other measurements. Workers are those that are intended to assess the size of specific quantities used by man. We can say that the meaning of such a classification is not in the accuracy of the instruments, but in the differences in purpose. There are various means by which the measurement is carried out. Types of measurement include special measures by which to reproduce any value of a specific size.

Single-valued and multivalued measures. Differences

Unambiguous and ambiguous measures also exist. The first include those that are able to show only quantities with the same size. With multi-valued playback of a sequence of different sizes is available. Such a measure can be called, say, a millimeter line. There are also unique sets that are formed from different sets of measures. They recreate the intermediate and total values of the quantities. In addition, measures, interacting, can perform a common work, and each can act separately. In order to compare the value with the measure, it is necessary to use a special device - a comparator. In the role of this tool is often the balance of the scales and the measuring bridge. If we study in more detail unambiguous measures, we can say that they are also classed as samples and substances acting in this role. They have a certain composition and properties. The slightest deviation is unacceptable. Such reference substances can help evaluate roughness, hardness, and reveal any other properties of materials. Samples help create points that form scales. Zinc and gold, for example, are used when it is required to recreate a certain temperature.

Ranks

The error in the evaluation classifies all measures into several consecutive digits. In the case of a deviation from the standard of measures themselves, class division is formed. Units of a certain level check the errors of the measuring instruments, due to which they are counted as samples.

Converters. General information

A measuring device that generates data from the information obtained after measurement that can be converted, stored and processed, but does not open to them visual access, is called a measuring transducer. What is its action? Let us consider this in more detail.

The essence of the transformation

When a value is just prepared for processing, it is called the input value. And the information obtained becomes "output". A converter-amplifier is a device that does not change the physical state of the data being processed, and the transformation has the form of a linear function. The term "amplifier" is used together with a word explaining its action. For example, a "voltage amplifier". If, during conversion, the value is converted to another, the name of the device is derived from the new value - "electromechanical".

Types of transducers

Depending on which part of the device it is in, the converter can be primary. This means that the measured value passes directly through it. He can be transmitting. In this case, the values appear after processing. The converter can be intermediate. It is located behind the primary.

Devices. General information

Measuring instruments are considered as such means of obtaining data on the value that represent them in a format that is accessible for visual examination. Depending on the type of evaluation, they are combined into specific groups. So, the most common are devices that conduct direct measurements. Their peculiarity is that they convert the original data without leaving information about their initial state. There are also devices, with the help of which indirect measurements are carried out.

Comparison devices

However, devices with direct action are not the most accurate. This characteristic is much higher in the comparison device. His work is based on the comparison of the data obtained when measuring the studied value with the already known information about other values. This method is called "indirect measurements." Their receipt is possible if the source data are available. In other words, the parameters are formed from the indicators that give a direct measurement. Types of measurement have several more categories. In order to compare the values, it is necessary to use compensating or bridge circuits. The first to compare those quantities that have some energy or force. This method is based on the fact that the quantities being compared are connected to the contour of the chain and their manifestation is studied. In the same case, if the value is considered passive, that is, it has resistance, bridges are used.

Distribution by reference method

Instruments have different methods of counting data for the studied quantities. Therefore, a special classification was created. On its basis, we can conclude that there are reproducing devices, which include not only analog but also digital ones. Another kind of devices are those that register information. The most popular are analog devices. Their component, responsible for maintaining a reference, is formed from two details. The first is the scale that is connected to the moving part. Another element of the device is a pointer connected to the body of the device. The action of meters, whose operation is based on the digital principle, is the result of the action of mechanical and electronic elements.

Variability by the recording method

There is another classification of recording instruments. For example, according to the method by which the registration device data is recorded. There are instruments-recorders, as well as printers. The former provide the received and processed information and aggregate measurements in the form of graphs, diagrams and diagrams. Registrars working on the second principle give out the results of work on a tape of paper, converting them into numerical series. Very often there are devices working on a comparison model, which is a combination of all the above types, that is, they represent a set of work of counting on a scale and a digital technique. Data logging, processing and printing can be done both as graphs with diagrams and as series of numerical values and numbers.

Auxiliary Elements of Evaluation

There are also auxiliary instruments and means for conducting measurements. The peculiarity of such devices is that they not only conduct the study of quantities independently. They can regulate the work of the main element, changing its action at the time of reading the information, as well as when processing it or issuing it. The data, which are provided by additional means, help to monitor and edit the readings of the devices. For example, for more accurate operation of thermometers, it is also necessary to install pressure gauges measuring the pressure of the environment. In addition, auxiliary devices can change the settings of the meter. So, in the case of using a device for recording the humidity level, you need to set the range values.

Settings

There are situations where, in order to get more accurate measurement data, one device is not enough. In this case, complex assemblies consisting of devices for different purposes are assembled. They are located in a certain sequence in a limited area. Some of the devices used convert the aggregate measurements into a single system. It is provided to the person responsible for collecting, organizing and processing information to the observer.

Systems

At another level are the measuring systems. The difference between such complexes and the above-described facilities is that they can be scattered over vast territories, and communicate through special information channels. Data in such systems are provided in two forms. One of them is more accessible for a real person who studies the results of work. The processing of the other is the computer.

Indicators

There are devices whose task is to read the manifestations of physical properties. They are called indicators. Even from the school chemistry course, litmus papers are known to all related to the means of indication. The compass needle is also considered such a device. Moreover, the meter that displays the level of fuel in the car's gasoline tank is also an indicator.