Precision active power measuring channel

The article is devoted to increasing the reliability, noise protection and improving the metrological characteristics of active power measuring converters. Much attention is paid to the problem of developing effective methods for constructing structural diagrams of active power measuring converters. This is explained by the growing requirements for the basic metrological characteristics of active power measuring converters as elements of information – measuring systems. The main attention in the work is paid to the development of ways to correct the influence of destabilizing factors in working conditions. The undoubted advantage of the work is a thorough analysis of the instrumental errors of the measuring channel, the original means of correction of the phase error and the error due to the limited suppression coefficients of in-phase interference. The obtained simulation results in the Electronics Workbench environment made it possible to determine the most effective way to protect against interference.

Information Conversion in Measuring Channels with Optoelectronic Sensors

The purpose of this work is the authors’ attempt to identify the main phases of information transformation in measurement channels on the example of an optical measurement channel with microprocessor control. The authors include such phases: hardware implementation and analytical representation of an optical sensor`s converting functions and a current-to-voltage converter; based on the methods of experimental computer science, the converting functions and sensitivity are deduced, analytical dependences for estimation of a range of measurement are obtained. It is shown that the choice of information transmission type in the microprocessor measuring channel significantly affects the speed of the measuring channel. Based on the uncertainty in the form of entropy before and after measurements, the amount of information for measuring channels with optoelectronic sensors is estimated. The application of the results obtained in the work allows even at the design stage of physical and mathematical modeling to assess the basic static metrological characteristics of measuring channels, aimed at reducing the stage of development and debugging of hardware and software and standardization of their metrological characteristics.

Исследование градуировочной характеристики турбинных преобразователей расхода жидкости типа MVTM

Most of the failures of turbine flow converters (TFC) used in the Russian system of main oil pipelines and oil product pipelines are caused by abrupt changes in the viscosity of the transported medium. In studies related to determination of the influence of the rheological properties of the pumped oil on the metrological characteristics of TFC that have a calibration curve in the form of a piecewise approximation without taking into account the correlation of TFC rotor speed with the viscosity of the pumped liquid in the flow rate subrange, the instability of the metrological characteristics in the operating range is observed. Taking into account the tendency to increase the volume of production and pumping of high-viscosity oils it can be assumed that the irregularity of the metrological characteristics of TFC, expressed in the change in the conversion factor will remain, which will negatively affect the reliability of accounting operations using oil quality control system (OQCS). Accordingly there is a need to maintain the error of TFC within the set limits in the subranges and throughout the entire range of flow rates. According to the results of the study performed by the authors it was confirmed that for the TFC of MVTM type the use of the calibration curve in the form of a piecewise-parabolic approximation with the dependence of the conversion factor on the ratio of TFC pulse frequency to the oil viscosity makes it possible to minimize the effect of changes in the parameters of the pumped medium on the measurement accuracy and as a consequence to stabilize the metrological characteristics of TFC in the recalibration interval, eliminate the costs of performing out-of-turn verifications, increase the accuracy and metrological reliability of the OQCS. Большинство отказов турбинных преобразователей расхода (ТПР), используемых в российской системе магистральных нефтепроводов и нефтепродуктопроводов, обусловлено резкими изменениями вязкости транспортируемой среды. В исследованиях по определению влияния реологических свойств перекачиваемой нефти на метрологические характеристики ТПР, имеющих градуировочную характеристику в виде кусочно-линейной аппроксимации без учета корреляции частоты вращения ротора ТПР с вязкостью перекачиваемой жидкости в поддиапазоне расхода, отмечается нестабильность метрологических характеристик в рабочем диапазоне. Учитывая тенденцию увеличения объема добычи и перекачки высоковязких нефтей, можно предположить, что непостоянность метрологических характеристик ТПР, выражаемая в изменении коэффициента преобразования, сохранится, что негативно скажется на достоверности учетных операций с применением систем измерений количества и показателей качества нефти (СИКН). Соответственно, возникает потребность в поддержании погрешности ТПР в установленных пределах в поддиапазонах и во всем диапазоне расходов. По результатам проведенного авторами исследования подтверждено, что для ТПР типа MVTM использование градуировочной характеристики в виде кусочно-параболической аппроксимации с зависимостью коэффициента преобразования от отношения частоты импульсов ТПР к вязкости нефти позволяет минимизировать влияние изменений параметров перекачиваемой среды на точность измерений и, как следствие, стабилизировать метрологические характеристики ТПР в межповерочном интервале, исключить затраты на выполнение внеочередных поверок, повысить точность и метрологическую надежность СИКН.

Fiber-optic sensor for remote monitoring the γ-radiation of various powers

The necessity of improving the metrological characteristics and functional capabilities of the fiber-optic sensor for measurements at the large distances (more than 10 km) is substantiated. The new method for constructing a communication line with the fiber-optic sensor for controlling exposure dose in a large range of its variation (several orders of magnitude) in a remote mode is proposed. The functional capabilities of the sensor are determined; its connection setup and measurement limits are developed. The experimental results are presented.

The use of digital data processing to improve the metrological characteristics of the rubidium frequency standard

The necessity of improving the metrological characteristics of a quantum frequency standard when determining the coordinates of an object on the Earth’s surface or long-term transmission of large amounts of data in satellite communication systems is substantiated. A new algorithm for digital processing of optical signals in the frequency standard is proposed. The results of experimental studies of the metrological characteristics of a quantum frequency standard based on rubidium atoms - 87 are presented

ВИДИ МЕТРОЛОГІЧНИХ ХАРАКТЕРИСТИК І СКЛАДУ РОБІТ З ЇХ ВИЗНАЧЕННЯ НА ОСНОВНИХ СТАДІЯХ ІСНУВАННЯ КОМПОЗИТНИХ КОНСТРУКЦІЙ АГРЕГАТІВ ПОВІТРЯНИХ СУДЕН ТРАНСПОРТНОЇ КАТЕГОРІЇ

It is shown that the development of the concept of metrological support for the creation of composite structures of aircraft aggregates of the transport category and their support at all stages of the existence of an aircraft should be based on the formation of a complex criterion for the effectiveness of the use of polymer composite materials. It is noted that the effectiveness of a structure made of polymer composite materials is provided by various methods, methods and technical means of metrology. The structure of a complex of studies aimed at developing the concept of metrological support is discussed, the first point of which is to analyze the types of metrological characteristics and the scope of work to determine them at the main stages of the existence of composite structures of aircraft aggregates of the transport category. Based on the analysis of numerous publications on the problem of metrological support of the main stages of creating technical products, the main types of measurements of the metrological characteristics of composite structures of aircraft aggregates of the transport category have been established, and the composition of the nomenclature of works on metrological support of the main stages of the existence of these structures has been determined. 12 main types of measurements of parameters have been identified, on which the whole variety of production physical quantities and the description of the properties and characteristics of structures of aircraft aggregates made of polymer composite materials are based. The composition of the main works on the metrological support of the four stages of the existence of the aircraft is revealed: design, production, operation and disposal of composite structures formed into systems of sequential blocks for performing these works. It is shown that the tasks of metrological support at the facility manufacturers should be solved during the technological preparation of serial production and testing of the installation series of products, and also take into account the peculiarities of aircraft operation and disposal of composite structural elements in terms of work safety and economic efficiency of their results. An enlarged sequence has been established for organizing work on metrological support for measuring the properties of composite structures of aircraft aggregates at aviation enterprises. The results presented in the first approximation provide a solution to practically important aspects of the problem under discussion.

Розробка стенду для вимірювання метрологічних характеристик електродвигунів

The problems of accurate measurement of the forces transmitted to the rotating shafts of electric motors have been solved for more than one century. At the same time, they have not lost their relevance, which is due to the wide development and variety of electric motors and power plants, the specific operating conditions of which require the use of a wide arsenal of measuring instruments. An important aspect in the process of using high-precision electric motors in such areas as medicine, vehicles, military-industrial complex is the improvement of the metrological characteristics of measuring equipment. In such conditions, power measurements at high-speed installations, where in some cases conventional measurement systems are either unsuitable or have low accuracy, are of particular importance. At the same time, in the absence of means of accurate determination of the error, attempts are made to predict them, which makes it possible to determine the influence of subtle factors on the efficiency of power plants. Even under optimal conditions for the functioning of measuring instruments, due to the influence of a number of factors, gross errors may appear. Such errors are unpredictable, and their significance is difficult to predict. To prevent the impact of negative factors on the operation of measuring instruments, additional sensors are often used, for example, to identify unnecessary vibrations, vibrometers are used in parallel with strain gauges. In the absence of such additional measuring sensors, in order to identify gross errors in diagnosing the characteristics of the moment of force, it is advisable to use machine learning tools, factor analysis techniques, simulation modeling, and other forecasting tools. With the help of such methods, among the sampling of data obtained from strain gauges, or other sensors, for measuring the moment of force, it is possible to identify deviations from normal operation, through certain frequency patterns of such influences. Among the many works describing the characteristics of errors in measuring physical quantities, there are not many that are devoted to predicting the accuracy of measuring sensors. Thus, when the measured conditions change, gross errors occur that negate the process of controlling electric motors, which is often the cause of an emergency condition. To solve this problem, you need simple and affordable tools that will allow you to form a classification of deviations in measurement errors. However, taking into account a significant number of factors of influence on the measuring medium, this can be realized only under the condition of an individual approach to the construction of measuring instruments. For this purpose, a stand was developed for measuring the metrological characteristics of electric motors. It was tested in conditions of increased vibration. The results of such tests made it possible to determine the deviations from the nominal error value of the strain gauge sensor.And also highlight a number of features of such a deviation caused by the frequency characteristics of the pulse source. The structure of the software and technical characteristics of the proposed stand and its comparison with existing analogs, as well as the functional and electrical circuit are presented. As a result of testing the proposed stand, a classification of factors influencing the accuracy of strain gauges was developed.