SU940077A1

SU940077A1 - Device for touch-free measuring of electric signals

Info

Publication number: SU940077A1
Application number: SU803225032A
Authority: SU
Inventors: Николай Иванович Яковлев
Original assignee: Предприятие П/Я Г-4377
Priority date: 1980-12-26
Filing date: 1980-12-26
Publication date: 1982-06-30

Description

Изобретение относится к электроизмерительной технике.и может быть использовано при контроле и диагностике электронной аппаратуры, а также при измерении электрических сигналов в электрооборудовании без разрыва то- ⁵топроводящих соединений и нарушения изоляционных покрытий.The invention relates to electrical engineering. And can be used in monitoring and diagnostics of electronic equipment, as well as in measuring electrical signals in electrical equipment without breaking current- ⁵ conductive compounds and breaking insulation coatings.

Известны устройства для бесконтактного измерения электрических сигналов в проводниках с помощью электромагнитных преобразователей, реагирующих на величину электрической или магнитной составляющей электромагнитного поля, создаваемого вблизи про-₁₅водника измеряемым сигналом, сигнал преобразователя усиливается и поступает на выходное индикаторное устройство fl ].A device for contactless measurement of the electrical signals in the conductors through electromagnetic transducers responsive to the magnitude of the electric or magnetic component of the electromagnetic field generated near the superconductor ₁₅ pro- measured signal, the transducer signal is amplified and supplied to an output display device fl].

Недостатком таких измерительных ?о устройств является зависимость их показаний от расстояния до проводника с измеряемым сигналом, что снижает точность измерений.The disadvantage of such measuring devices is the dependence of their readings on the distance to the conductor with the measured signal, which reduces the accuracy of the measurements.

Наиболее близким по технической сущности к предлагаемому является устройство для бесконтактного измерения импульсных токов в проводнике, содержащее два закрепленных на неизменном расстоянии г_о друг от другй электромагнитных преобразователя, соединенных с соответствующими интегрирующими усилителями, выходы которых присоединены к последовательно соединенным измерителю отношений и функциональному преобразователю, связанному с выходным регулируемым усилителем и индикатором £2].The closest in technical essence to the proposed is a device for contactless measurement of pulse currents in a conductor, comprising two fixed at a constant distance r _of each of other electromagnetic transducer connected to respective integrating amplifiers whose outputs are connected to a series connected meter relationship and functional transducer associated with output adjustable amplifier and indicator £ 2].

В известном измерительном устройстве уменьшение зависимости показаний от изменения расстояния между проводником и первым преобразователем достигается за счет того, что при изменении расстояния г^ величиной коэффициента усиления усилителя управляет функциональный преобразователь, подключенный к измерителю отношений. Поскольку сигналы и У^на выходах первого и второго преобразователей соответственно обратно пропорциональны расстояниям г₄ и г^ от них до проводника с измеряемым током, 1, т.е. VjM/q , ^=1/^=1/(^ + + г_о ), то сигнал V_o на выходе измерителя отношений и входе функционального преобразователя, в общем случае нелинейным образом зависит от расстояния г, :V_Q= V₂/V₄ =i/(+r_o/r;. Поэтому при использовании для усиления сигнала V₄ линейного усилителя, коэффициент усиления которого регулируется напряжением V©, выходной сигнал не зависит от расстояния до проводника только в том случае, когда /0^1^0=^0Однако это условие практически трудно выполнимо, так как при большом удалении второго преобразователя от проводника, т.е. при г_о г^ , возникают погрешности измерения изза резкого ослабления сигнала и влияния помех, а при соизмеримых расстояниях г₀ < г^ остаются погрешности, обусловленные изменениями расстояния г^ при измерениях. В свою очередь, обеспечивать изменение коэффициента усиления по сложному нелинёйному закону регулирования с высокой точностью в широком диапазоне частот и амплитуд измеряемого сигнала весьма трудно, что снижает точность измерения рассматриваемого устройства.In the known measuring device, a decrease in the dependence of the readings on the change in the distance between the conductor and the first converter is achieved due to the fact that when the distance r ^ changes, the gain of the amplifier is controlled by a functional converter connected to the ratio meter. Since the signals and U ^ at the outputs of the first and second converters are respectively inversely proportional to the distances r ₄ and r ^ from them to the conductor with the measured current, 1, i.e. VjM / q, ^ = 1 / ^ = 1 / (^ + + r _о ), then the signal V _o at the output of the ratio meter and the input of the functional converter, in the general case, non-linearly depends on the distance r,: V _Q = V ₂ / V ₄ = i / (+ r _o / r;. Therefore, when a linear amplifier is used to amplify the V ₄ signal, the gain of which is regulated by the voltage V ©, the output signal does not depend on the distance to the conductor only if / 0 ^ 1 ^ 0 ^ 0Odnako this condition is practically difficult to accomplish, since the large distance from the conductor of the second inverter, i.e. at _about r r arise Mayhem of the measurements due to the sharp signal attenuation and interference effects, and at comparable distances r ₀ <r are errors caused by changes in the distance r in the measurements. In turn, provide a change in the gain of the complex nelinoynomu law regulation with high accuracy in a wide frequency range and the amplitudes of the measured signal is very difficult, which reduces the measurement accuracy of the device in question.

Цель изобретения - повышение точности измерения.The purpose of the invention is to improve the accuracy of measurement.

Указанная цель достигается тем, что в устройство для бесконтактного измерения, содержащее два жестко связанных электромагнитных преобразователя, соединенных с соответствующими усилителями, измеритель отношения и выходное'индикаторное устройство, введены устройство перемножения сигналов, включенное между выходом первого усилителя и первым входом измерителя отношений, и вычитающее устройство, включенное между выходом вто-^° рого усилителя и вторым входом измерителя отношений, при этом один вход устройства перемножения связан с выходом первого усилителя и первым входом вычитающего устройства, второй вход которого связан с другим входом устройства перемножения и выходом второго усилителя.This goal is achieved by the fact that in the device for non-contact measurement, containing two rigidly connected electromagnetic transducers connected to respective amplifiers, a ratio meter and an output indicator device, a signal multiplier is inserted, connected between the output of the first amplifier and the first input of the ratio meter, and subtracting a device connected between the output of the second amplifier and the second input of the ratio meter, while one input of the multiplying device is connected to the output m of the first amplifier and the first input of the subtractor, the second input of which is connected to another input of the multiplication device and the output of the second amplifier.

На чертеже представлена блок-схема устройства.The drawing shows a block diagram of a device.

Устройство содержит два одинаковых жестко скрепленных на расстоянии г_{р 5} электромагнитных преобразователя 1 и 2, устанавливаемых около проводника 3 с измеряемым сигналом, в данном случае током I. К выходам преобразователей 1 и 2 присоединены со10 ответственно усилители 4 и 5, выход первого из которых подключен к одному входу устройства 6 перемножения и первому входу вычитающего устройства 7, а выход второго - соответствен15 но к вторым входам устройства 6 перемножения и вычитающего устройства 7, выходы которых присоединены к входам измерителя 8 отношений с последующим выходным индикаторным уст_м ройством 9.The device contains two identical electromagnetic transducers 1 and 2, rigidly fixed at a distance of r _{p 5} , installed near the conductor 3 with a measured signal, in this case, current I. Amplifiers 4 and 5 are connected to the outputs of converters 1 and 2, the output of the first of which is connected to one input of the multiplication device 6 and the first input of the subtracting device 7, and the output of the second is, respectively, 15 to the second inputs of the multiplying device 6 and the subtracting device 7, the outputs of which are connected to the inputs of the meter 8 about elations followed output indicator mouth roystvom 9 _m.

Устройство работает следующим образом.The device operates as follows.

Для измерения электрического сиг25 нала, например тока 7 в проводнике, электромагнитный преобразователь 1 подносят к проводнику и устанавливают на некотором расстоянии г₄ от него» Поскольку второй преобразова₃₀ тель жестко соединен с первым на расстоянии г_о, то расстояние от проводника до второго преобразователя равно Γ2_=γ₄+γ₀. Протекающий по проводнику измеряемый ток 7 создает вокруг него электромагнитное поле, которое создает в преобразователях 1 и 2 соответственно электрические сигналы, обратно пропорциональные расстояниям до них г^ и г₂. Эти сигналы усиливаются одинаковыми линейными уси-. лителями 4 и 5 с коэффициентом усиления к и становятся на их выходах соответственно равными =к I/tj , Vx=k · I / Гз_.To measure an electric signal, for example, current 7 in a conductor, the electromagnetic transducer 1 is brought up to the conductor and installed at a certain distance r ₄ from it. ”Since the second transformer _{30 is} rigidly connected to the first one at a distance r _o , the distance from the conductor to the second transducer is Γ2_ = γ ₄ + γ ₀ . The measured current 7 flowing through the conductor creates an electromagnetic field around it, which creates in the converters 1 and 2, respectively, electrical signals inversely proportional to the distances to them r ^ and r ₂ . These signals are amplified by the same linear amplifiers. amplifiers 4 and 5 with a gain of k and become at their outputs respectively equal to = k I / tj, Vx = k · I / Гз_.

Чтобы обеспечить независимость показаний от изменения расстояния между проводником с измеряемым сигналом и электромагнитными преобразователями, сигнал поступает на первые входы вычитающего устрой-, ства 7 и устройства 6 перемножения, а с их выходов - на измеритель 8 отношений. Одновременно сигнал V₂поступает соответственно на вторые входы устройства 6 перемножения и вычитающего устройства 7-и аналогичным образом на измеритель 8 отношений. При этом на первом входе изме10 сигнала и fa между проводи элек15 рителя 8 отношений сигнал равен а на втором входе % _ JS1 _ КЗ Ус ,In order to ensure that the readings are independent of changes in the distance between the conductor with the measured signal and electromagnetic transducers, the signal is fed to the first inputs of the subtractor, device 7 and multiplier 6, and from their outputs to the relationship meter 8. At the same time, the signal V _{2 is} supplied respectively to the second inputs of the multiplication device 6 and the subtracting device 7 in a similar manner to the ratio meter 8. In this case, the signal at the first input of the signal and fa between the wires of the elec tron 8 of the 8 ratios is equal to and at the second input% _ JS1 _ KZ Us,

ВХ' п, г_г . Соответственно выходной сигнал измерителя отношений, поступающий на устройство 9 индикации, оказывается пропорциональным измеряемому току V - Чх юBX 'n, r _r. Accordingly, the output signal of the ratio meter, arriving at the display device 9, is proportional to the measured current V - xx y

В предлагаемом устройстве, в отличие от известных, достигается полная независимость выходного от расстояний q ником с измеряемым сигналом тромагнитными преобразователями, так как выходной сигнал зависит только от величины измеряемого сигнала I, коэффициента усиления к и расстояния г₀ между преобразователями, ‘ которое остается неизменным при любых значениях ги fa.In the proposed device, in contrast to the known ones, complete independence of the output from the distances q by the nickname with the measured signal by the magnetic transducers is achieved, since the output signal depends only on the value of the measured signal I, the gain k and the distance r ₀ between the transducers, which remains unchanged any values of gi fa.

Таким образом, благодаря введению линейных устройств перемножения и вычитания, включенных указанным вы- . ше способом, обеспечивается более высокая, чем в известных устройствах, точность бесконтактных измерений электрических сигналов в широком диапазоне измерения при изменениях расстояния между проводником с измеря·' емым сигналом и бесконтактными электромагнитными преобразователями.Thus, thanks to the introduction of linear devices of multiplication and subtraction, included the specified you. In a way that provides higher than non-known devices, the accuracy of non-contact measurements of electrical signals in a wide measuring range when the distance between the conductor with the measured signal and non-contact electromagnetic converters changes.

Предлагаемое устройство универсально, так как позволяет преобразовывать сигналы как в аналоговой, так и в цифровой форме, и может использоваться, в зависимости от типа применяемых электромагнитных преобразователей, как для измерения электрического тока, так и электрического напряжения□ В этом случае элекThe proposed device is universal, since it allows you to convert signals in both analog and digital form, and can be used, depending on the type of electromagnetic transducers used, both for measuring electric current and voltage □ In this case, the electric

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' 940077 6 тромагнитные преобразователи реагируют на пропорциональную напряжению ‘ проводника напряженность электрического поля, которая также убывает пропорционально расстоянию до него, поэтому преобразования характеризуются закономерностями, аналогичными рассмотренным выше.'940077 6 electromagnetic transducers react to the electric field strength proportional to the voltage ‘of the conductor, which also decreases in proportion to the distance to it, so the transformations are characterized by regularities similar to those considered above.

Claims

The invention relates to electrical measuring equipment. It can be used in monitoring and diagnostics of electronic equipment, as well as in measuring electrical signals in electrical equipment without breaking the conductive connections and breaking insulation coatings. Devices for contactless measurement of electrical signals in conductors by means of electromagnetic transducers, which react to the magnitude of the electric or magnetic component of an electro-magnetic field created near the conductor by the measured signal, are known. The transducer signal is amplified and fed to the output indicator device 1. The disadvantage of such measuring devices is the dependence of their readings on the distance to the conductor with the measured signal, which reduces the measurement accuracy. The closest in technical essence to the present invention is a device for contactless measurement of pulse currents in a conductor containing two electromagnetic converters fixed at a constant distance r from one another and connected to corresponding integrating amplifiers, the outputs of which are connected to series-connected relationship meter and functional converter associated with an output adjustable amplifier and indicator

2. In a known measuring device, a decrease in the dependence of the indications on a change in the distance n between the conductor and the first transducer is achieved due to the fact that when the distance r is changed, the amplification factor of the amplifier controls the function converter connected to the ratio meter. Since the signals V and 3E of the outputs of the first and second transducers, respectively, are inversely proportional to the distance m g and T2. from ton to conductor with measured 1 / (g, com, i.e., (, V, jl / r + g), then the VQ signal at the output of the measurement of the relation body and the input of the functional converter, in general, depends nonlinearly on distance vj / v. Therefore -f 2 SI1- when used to amplify the voltage V of a linear amplifier, the gain of which is controlled by the voltage Vo, the output signal does not depend on the distance r to the conductor only. However, this condition practically difficult to accomplish, since with a large distance of the second converter from the conductor i.e., when measurement measurements occur because of a sharp weakening of the signal and the influence of interference, and at commensurate distances Gyyy, errors remain due to changes in the distance of the city during the measurements. In turn, to provide a change in the gain factor for a complex non-linear regulation with high accuracy in a wide range of frequencies and amplitudes of the measured signal is very difficult, which reduces the measurement accuracy of the device under consideration. The purpose of the invention is to improve the measurement accuracy. This goal is achieved by the fact that a multiplier device connected between the output of the first amplifier and the first input of the ratio meter is inserted into a device for contactless measurement, which contains two rigidly coupled electromagnetic transducers connected to appropriate amplifiers, a ratio meter, and an output Indicator device. and a subtractive device connected between the output of the second amplifier and the second input of the ratio meter, with one input of the multiplication device being connected to the output house the first amplifier and the first input of the subtractor, the second input of which is connected to another input of the multiplying device and the output of the second amplifier. The drawing shows the block diagram of the device. The device contains two identical electromagnetic transducers 1 and 2, rigidly fastened at a distance g, installed near conductor 3 with the measured signal, in this case current I. Amplifiers 4 and 5, respectively, are connected to the outputs of transducers 1 and 2, respectively. one input of the multiplication device 6 and the first input of the subtracting device 7, and the output of the second one, respectively, to the second inputs of the multiplication device 6 and the subtractive device 7, the outputs of which are connected to the inputs of the meter 8 are relative eny followed output display device 9. The device operates as follows. To measure an electrical signal, such as current 7 in a conductor, the electromagnetic transducer 1 carries a conductor and is set at a distance r from it. Since the second transducer is rigidly connected to the first at the distance of the PO, the distance from the conductor to the second transducer is equal. A measuring current flowing through a conductor creates an electromagnetic field around it, which creates electrical signals in converters 1 and 2, respectively, inversely proportional to the distances m and r / j to them. These signals are amplified by the same linear usi. 4 and 5 with a gain k and become at their outputs, respectively, V kl / tj, V2. To ensure that the readings are independent of the change in the distance between the conductor with the measured coaxial and electromagnetic converters, the signal V goes to the first inputs of the subtractor. 7 and the device 6 multiplies, and from their outputs - on the meter 8 ratios. At the same time, the signal J is fed respectively to the second inputs of the multiplication device 6 and the subtractive device 7 in a similar way to the meter 8 ratios. At the same time, at the first input, a measure of 8 signal ratios is equal to 3 at the second input of v - .. (T -up r Ti) T2. . Correspondingly, the output signal of the measurement of the relationship bodies arriving at the display device 9 turns out to be proportional to the measured current V - κ J2 b "° v; In the proposed device, unlike the known ones, the field reaches the output signal independence from the distances r and d between the conductor with the measured signal and the electromagnetic transducers, since the output signal depends on the measured signal I, gain k and the distance Gy between the converters, which remains unchanged for any values of r and r. Thus, due to the introduction of linear multiplication and subtraction devices included in the above method, the accuracy of contactless measurements of electrical signals in a wide measuring range with changes in the distance between the conductor with the measured signal and the contactless electromagnetic converters is higher than in known devices. mi The proposed device is universal, as it allows to convert signals in both analog and digital form, and can be used, depending on the type of electromagnetic transducer used, both for measuring electric current and electric voltage. In this case 76 Magnetic transducers react to a voltage proportional to the conductor voltage of the electric field, which also decreases in proportion to the distance to it, therefore the transformations are characterized by the law polarities similar to those discussed above. An apparatus for contactless measurement of electrical signals, comprising two rigidly coupled electromagnetic transducers connected to respective amplifiers, a ratio meter and an output indicating device, characterized in that, in order to improve the measurement accuracy, a signal multiplying device is inserted between the output of the first the amplifier and the first input of the ratio meter, and the subtractive device connected between the output of the second amplifier and the second input of the meter relations, wherein the first input of the multiplication device is connected with the output of the first amplifier and the first input of the subtracting device, the second input of which is connected with the second input of the multiplying device and the output of the second amplifier. Sources of information taken into account in the examination 1. USSR author's certificate number bTZE, cl. G 01 R 13/00, 1978. 2, USSR Copyright Certificate N, cl. G 01 R 19/0, 1978.