WO2022024249A1 - Measurement system and measurement method - Google Patents

Abstract

A calculation device 8 comprises: a generation unit 81 that generates a list during a condition in which a measurement instrument 1 and a correction device 2 are each positioned on a dielectric plate 4, said list associating, for each time the thickness of the dielectric plate 4 is changed, variation voltage values that were measured by the correction device 2, and correction data values that are used in order to correct an error in the line-to-ground voltage of electromagnetic noise and were measured by the measurement instrument 1 on the basis of false electromagnetic noise; and a correction unit 82 that, during a condition in which the measurement instrument 1 and the correction device 2 are each positioned in an electromagnetic noise measurement location, acquires, from the list, the correction data value corresponding to the variation voltage value measured by the correction device 2, and uses the correction data value to correct the line-to-ground voltage of the electromagnetic noise measured by the measurement instrument 1.

Description

Measurement system and measurement method

The present invention relates to a measurement system and a measurement method.

Electromagnetic noise in the same frequency band as the signal used for communication invades the communication device via the power cable or communication cable, causing a communication failure in the communication device. For example, electromagnetic noise of several hundred kHz to several MHz generated from a quick charger of an electric vehicle may block ADSL communication in the same frequency band.

Electromagnetic noise is an electric signal that cannot be seen with the naked eye, and communication failure due to electromagnetic noise cannot be visually identified as the cause of the failure, such as a broken cable. Therefore, when a communication failure suspected to be caused by electromagnetic noise occurs, the maintenance person measures the intensity and frequency of the electromagnetic noise flowing through the cable using a measuring instrument such as an oscilloscope. At that time, since the electromagnetic noise often forms a loop whose return path is the ground or a large conductor connected to the ground (hereinafter referred to as the ground), the voltage between the cable to be measured and the ground, that is, the measurement Measure the voltage to ground of the electromagnetic noise flowing through the target cable.

Normally, the voltage to ground of electromagnetic noise is measured by grounding the measuring instrument to be used and contacting or clamping the passive probe or capacitive voltage probe (see Non-Patent Document 1) of the measuring instrument to the cable to be measured. Will be done. On the other hand, when it is difficult to ground the measuring instrument, the ground voltage of electromagnetic noise is measured without grounding the measuring instrument, and the ground capacitance measuring mechanism installed at the same altitude as the measuring instrument (non-grounding). (See Patent Document 2) indirectly measures the ground capacitance of the measuring instrument. Then, by correcting the ground voltage of the electromagnetic noise with an error measured by the measuring instrument by using the ground capacitance of the measuring instrument measured by the ground capacitance measuring mechanism, an accurate ground voltage of the electromagnetic noise is obtained (Non-Patent Document). 3).

Ryuichi KOBAYASHI, 5 outsiders, “A Novel Non-contact Capacitive Probe for Common-Mode Voltage Measurement”, IEICE TRANS. COMMUN., VOL.E90-B, NO.6, DOI: 10.1093 / ietcom / e90-b.6.1329 , June 2007, p.1329-p.1337 Toshito Arai, 2 outsiders, "Proposal of estimation method of ground capacitance for simple grounding of measuring instrument", March 19-22, 2019, IEICE General Conference, B-4- 44, Correspondence Lecture Proceedings 1, p.264 Naruto ARAI, 3 outsiders, “Method of Measuring Conducted Noise Voltage with a Floating Measurement System to Ground”, IEICE TRANSACTIONS on Communications, DOI: 10.1587 / transcom.2019MCP0001, The Institute of Electronics, Information 8th, p.1-p.9

By using the techniques of Non-Patent Documents 2 and 3, it is possible to accurately measure the ground voltage of electromagnetic noise even when the measuring instrument is in a non-grounded state. However, the ground capacitance C formed between the conductor plate connected to the ground line of the measuring instrument and the ground and the ground capacitance C of the electrode of the ground capacitance measuring mechanism are the conductor plate or the area S of the electrode and the conductor plate, respectively. Alternatively, it is assumed that it is expressed by the equation (1) using the thickness d _k of the substance existing between the electrode and the ground and the relative permittivity ε _k . Note that ε ₀ is an electric constant. N is the total number of material layers existing between the electrode and the ground.

However, if the measurement location where the measuring instrument and the ground capacitance measuring mechanism are installed is far from the ground, the equation (1) does not hold, so the accurate ground capacitance of the measuring instrument cannot be obtained, and the ground of electromagnetic noise cannot be obtained. There was a problem that the voltage could not be corrected by the ground capacitance of the accurate measuring instrument.

The present invention has been made in view of the above circumstances, and an object of the present invention is to measure the ground voltage of electromagnetic noise with a measuring instrument in a non-grounded state, in which a measuring place where the measuring instrument is installed and the ground are used. It is to provide a technique capable of accurately measuring the voltage to ground of electromagnetic noise even when the distance between them is large.

The measuring system of one aspect of the present invention is used for a measuring instrument that measures the ground voltage of electromagnetic noise without grounding the ground wire and for correcting the error of the ground voltage of the electromagnetic noise, and is used for correcting the error of the ground voltage of the self-correcting device. In a measurement system including a correction device that measures a fluctuating voltage that changes according to the magnitude of a capacitance, and a calculation device that is communicably connected to the measuring device and the correction device, the calculation device is used. In a state where the measuring instrument and the compensator are respectively installed on the dielectric plate, each time the thickness of the dielectric plate is changed, the value of the fluctuating voltage measured by the compensator and the electromagnetic noise A generator that is used to correct an error in the voltage to ground and generates a list relating the values of correction data measured by the measuring instrument based on pseudo-electromagnetic noise, and the measuring instrument and the correction device. The values of the correction data corresponding to the values of the fluctuation voltage measured by the correction device were acquired from the list and measured by the measuring instrument in a state where the and were installed at the measurement locations of the electromagnetic noise. It is provided with a correction unit that corrects the ground voltage of electromagnetic noise with the value of the correction data.

The measuring method of one aspect of the present invention is used for a measuring instrument that measures the ground voltage of electromagnetic noise without grounding the ground wire and for correcting the error of the ground voltage of the electromagnetic noise, and is used for correcting the error of the ground voltage of the self-correcting device. In a measurement method performed by using a correction device that measures a fluctuating voltage that changes according to the magnitude of a capacitance and a calculation device that is communicably connected to the measuring device and the correction device, the calculation device is used. In a state where the measuring instrument and the compensator are respectively installed on the dielectric plate, each time the thickness of the dielectric plate is changed, the value of the fluctuating voltage measured by the compensator and the electromagnetic noise. A step of generating a list relating the value of the correction data measured by the measuring instrument based on the pseudo-electromagnetic noise, which is used to correct the error of the voltage to ground, and the measuring instrument and the correction device. The values of the correction data corresponding to the values of the fluctuation voltage measured by the correction device were acquired from the list and measured by the measuring instrument in a state where the and were installed at the measurement locations of the electromagnetic noise. The step of correcting the ground voltage of the electromagnetic noise with the value of the correction data is performed.

According to the present invention, in a method of measuring the voltage to ground of electromagnetic noise with a measuring instrument in a non-grounded state, electromagnetic noise is generated even when the measurement location where the measuring instrument is installed is far from the ground. It is possible to provide a technology that can accurately measure the voltage to ground.

FIG. 1 is a graph showing the ground capacity of the conductor plate with respect to the thickness of the acrylic plate. FIG. 2 is a diagram showing an equivalent circuit in the case of measuring the voltage to ground of electromagnetic noise with a measuring instrument in a non-grounded state. FIG. 3 is a diagram showing the configuration of the correction device. FIG. 4 is a diagram showing an equivalent circuit of the correction device. FIG. 5 is a diagram showing a configuration of a measurement system at the time of pre-work. FIG. 6 is a diagram showing a processing flow of the preliminary work in the first embodiment. FIG. 7 is a diagram showing a processing flow of the measurement work in the first embodiment. FIG. 8 is a diagram showing a processing flow of the preliminary work in the second embodiment. FIG. 9 is a diagram showing a processing flow of the measurement work in the second embodiment. FIG. 10 is a diagram showing a hardware configuration of the arithmetic unit.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the description of the drawings, the same parts are designated by the same reference numerals and the description thereof will be omitted.

[Outline of the invention]
The present invention relates to a method for simply measuring electromagnetic noise generated in a power cable or a metal communication cable. As described above, when the measurement location where the measuring instrument and the ground capacity measuring mechanism are installed and the ground are separated, the equation (1) does not hold. For example, the capacitance between the first conductor plate and the second conductor plate when the first conductor plate of 250 mm × 120 mm is placed on the large second conductor plate with the acrylic plate sandwiched between them, that is, the first conductor. The ground capacitance of the board is shown in FIG.

The triangular plot in FIG. 1 is the first ground capacitance C1 of the first conductor plate obtained by electromagnetic field analysis. The round plot is the second ground capacitance C2 of the first conductor plate assuming that the equation (1) holds. The line connecting the square plot and the square plot is a graph showing how many times the second ground capacitance C2 is the first ground capacitance C1. The scales on the triangular and round plots are the scales on the left, and the scales on the line connecting the square plots and the square plots are the scales on the right.

In FIG. 1, the square plot and the line connecting the square plots gradually move away from 1 as the thickness of the acrylic plate increases. This indicates that the ground capacity model of the equation (1) does not hold when the measurement location where the measuring instrument and the ground capacity measuring mechanism are installed and the ground are separated.

Therefore, in the present invention, the equation (1) is not used, and a correction list for correcting the voltage to ground of electromagnetic noise is generated in advance, and the error is measured by a measuring instrument in a non-grounded state at the measurement location. The problem is solved by correcting the ground voltage of electromagnetic noise with an accurate error by using the correction list.

Specifically, the voltage to ground of inaccurate electromagnetic noise measured by a measuring instrument in a non-grounded state at the measurement location of electromagnetic noise is corrected by using the ground capacitance of the conductor plate connected to the ground line of the measuring instrument. A method (Example 1) and a method of correction using a predetermined correction coefficient (Example 2) are disclosed. In the present invention, a device having the same configuration as the "ground capacity measuring mechanism" used in the prior art is used, but since the ground capacity is not used in the present invention, the device is referred to as a "correction device".

For example, in the preliminary work, the measurement result measured by the correction device (variable voltage that changes according to the magnitude of the ground capacitance of the correction device) and the ground of the conductor plate connected to the ground line of the measuring device in the first embodiment. In the second embodiment, the capacity is related and the correction coefficient is related to make a list. After that, at the measurement location, the inaccurate electromagnetic noise to ground voltage measured by the measuring instrument in the ungrounded state is corrected by the ground capacitance or correction coefficient of the conductor plate corresponding to the measurement result (fluctuation voltage) measured by the correction device. ..

Since the present invention does not use the equation (1), the problem that the equation (1) does not hold does not occur, and the distance between the measurement place where the measuring instrument and the ground capacity measuring mechanism are installed and the ground becomes large. Even in this case, the voltage to ground of electromagnetic noise can be measured with high accuracy.

[Measuring instrument]
FIG. 2 is a diagram showing an equivalent circuit in the case of measuring the ground voltage of electromagnetic noise with the measuring instrument 1 in the non-grounded state. At the time of measurement, a conductor plate is connected to the ground wire of the measuring instrument 1 with a copper wire or the like, and the measuring instrument 1 is installed on the conductor plate. V _n is the voltage to ground of the electromagnetic noise to be measured. _Zn is an equivalent load impedance of electromagnetic noise. Z _m is the input impedance of the measuring instrument 1. V _m is the voltage to ground of the electromagnetic noise measured by the measuring instrument 1. C _m is the ground capacitance of the conductor plate connected to the ground wire of the measuring instrument 1. At this time, since _Zn is generally a small value, the ground voltage _Vm of the electromagnetic noise measured by the measuring instrument 1 is expressed by the equation (2). Note that ω _n is the angular frequency of electromagnetic noise. j is an imaginary unit.

From the equation (2), the ground voltage _Vm of the electromagnetic noise measured by the measuring instrument 1 is the ground voltage of the electromagnetic noise to be measured by the ground capacitance _Cm of the conductor plate connected to the ground wire of the measuring instrument 1. It is smaller than V _n . Therefore, in the first embodiment, the measuring instrument is solved by obtaining the ground capacitance C _{m from the correction list generated in the preliminary work and substituting the ground capacitance C m into} the equation (3) obtained by converting the equation (2). The ground voltage V _m of the electromagnetic noise measured in 1 is corrected to the ground voltage V _n of the electromagnetic noise to be measured.

In the second embodiment, the correction coefficient X is obtained from the correction list created in advance, and the correction coefficient X is calculated using the equation (4), whereby the ground voltage _Vm of the electromagnetic noise measured by the measuring instrument 1 is measured. It is corrected to the ground voltage _Vn of the electromagnetic noise. In the second embodiment, it is not necessary to obtain the ground capacitance _Cm of the conductor plate connected to the ground line of the measuring instrument 1.

[Example 1]
The first embodiment will be described.

FIG. 3 is a diagram showing the configuration of the correction device 2. The correction device 2 includes a voltage measuring circuit 21, an oscillation circuit 22, a first electrode 23a, a second electrode 23b, a third electrode 23c, a first spacer 24a, and a second spacer 24b. The first electrode 23a and the second electrode 23b are spaced apart from each other at the same altitude, and are arranged so as to face the third electrode 23c with the first spacer 24a interposed therebetween. The voltage measurement circuit 21 and the oscillation circuit 22 are connected in series. Each end of the voltage measuring circuit 21 is connected to the first electrode 23a and the third electrode 23c, respectively. Each end of the oscillation circuit 22 is connected to the second electrode 23b and the third electrode 23c, respectively. The second spacer 24b is arranged below the first electrode 23a and the second electrode 23b.

FIG. 4 is a diagram showing an equivalent circuit of the correction device 2 including the ground. When a signal is output from the oscillation circuit 22, a voltage _Vr is generated in the voltage measurement circuit 21. When the input impedance of the voltage measuring circuit 21 is designed to be sufficiently large, the voltage _Vr is expressed by the equation (5).

Note that V _out is the output voltage of the oscillation circuit 22. R _out is the output resistance of the oscillation circuit 22. C ₁ is the ground capacitance of the first electrode 23a. C ₂ is the ground capacitance of the second electrode 23b. C ₃ is the ground capacitance of the third electrode 23c. _C4 is the capacitance between the first electrode 23a and the third electrode 23c. C ₅ is the capacitance between the second electrode 23b and the third electrode 23c. ω is the angular frequency of the signal output from the oscillation circuit 22.

Equation (5) shows that the voltage _Vr changes depending on the values of C ₁ , C ₂ , and C ₃ . For example, when the values of C ₁ , C ₂ , and C ₃ are small, that is, when the distance between the correction device 2 and the ground is large, or when the relative permittivity of the substance between the correction device 2 and the ground is large. When is small, the voltage _Vr is a small value.

In order to obtain the ground capacitance _Cm (see FIG. 2) of the conductor plate connected to the ground line of the measuring instrument 1 at the measurement location of the electromagnetic noise by using this compensator 2, the voltage _Vr of the compensator 2 is used. , It is necessary to obtain the correspondence relationship with the ground capacitance _Cm of the conductor plate connected to the ground wire of the measuring instrument 1 in advance. Hereinafter, this preliminary work will be described.

FIG. 5 is a diagram showing a configuration of a measurement system at the time of pre-work. A dielectric plate 4 such as an acrylic plate or wood is placed on the shield room floor 3 as a large conductor, and the correction device 2 is placed on the dielectric plate 4. Next, a signal generator 5 that outputs a sine wave having a voltage of 2 V _nt and an angular frequency of ω _nt is connected to the shield room floor 3 with a resistor 6 having the same magnitude as the output impedance of the signal generator 5. This work is a work for making the resistance 6 generate a voltage of _Vnt corresponding to the ground voltage _Vn of the electromagnetic noise to be measured. Next, the conductor plate 7 is connected to the ground wire of the measuring instrument 1, and the conductor plate 7 is placed on the dielectric plate 4. The measuring instrument 1 is placed on the conductor plate 7. As a result, the altitudes of the correction device 2 and the conductor plate 7 become equal. Finally, the arithmetic unit 8 is connected to the measuring device 1, the correction device 2, and the signal generator 5 so as to be able to communicate with each other by wire or wirelessly.

In the measurement system of FIG. 5, the measuring instrument 1 measures the ground voltage _Vm of electromagnetic noise in a state where the ground line is not grounded. The correction device 2 is used to correct an error of the ground voltage _Vm of the electromagnetic noise measured by the measuring device 1, and changes according to the magnitudes of the ground capacitances C ₁ , C ₂ , and C ₃ of the correction device 2. , Measure the fluctuating voltage _Vr . The arithmetic unit 8 uses the ground voltage V _m of the electromagnetic noise measured by the measuring instrument 1 and the voltage V _n generated in the resistor 6 to obtain the ground capacitance C _m of the conductor plate connected to the ground wire of the measuring instrument 1. The correspondence between the voltage _Vr of the correction device 2 and the ground capacitance _Cm of the conductor plate connected to the ground line of the measuring instrument 1 is listed. The arithmetic unit 8 includes, for example, a generation unit 81 that functions during pre-work, a correction unit 82 that functions during measurement work at a measurement location, and a storage unit 83 that stores various data such as measurement results.

In the state where the measuring instrument 1 and the correction device 2 are respectively installed on the dielectric plate 4, the generation unit 81 changes the thickness of the dielectric plate 4, and the value of the voltage _Vr measured by the correction device 2 is changed. And, it is used to correct the error of the voltage to ground _Vm of the electromagnetic noise measured by the measuring instrument 1, and the correction measured by the measuring instrument 1 based on the signal as the pseudo electromagnetic noise output from the signal generator 5. It has a function of generating a list related to the value of the data for use and storing it in the storage unit 83.

The correction unit 82 stores the value of the correction data corresponding to the value of the voltage _Vr measured by the correction device 2 in a state where the measuring device 1 and the correction device 2 are installed at the measurement locations of the electromagnetic noise, respectively. It has a function of correcting the ground voltage _Vm of the electromagnetic noise measured by the measuring instrument 1 with the value of the correction data acquired from the list of 83.

In the first embodiment, the value of the correction data is the ground capacitance of the conductor plate 7 connected to the ground wire of the measuring instrument 1 and installed on the dielectric plate 4. In the second embodiment described later, the value of the correction data can be obtained by multiplying the ground voltage V _m of the electromagnetic noise measured by the measuring instrument 1 with the ground voltage V _n of the corrected electromagnetic noise. Correction factor. Specifically, it is the ratio of the voltage V _n generated in the resistor 6 by the signal output from the signal generator 5 to the ground voltage V _m of the electromagnetic noise measured by the measuring instrument 1.

FIG. 6 is a diagram showing a processing flow of the preliminary work in the first embodiment.

Step S101;
First, the correction device 2 measures the voltage _Vr . The correction device 2 transmits the measurement result of the voltage _Vr to the arithmetic unit 8. The arithmetic unit 8 stores the measurement result of the voltage _Vr .

Step S102;
Next, the signal generator 5 outputs a sine wave having a voltage of 2 _Vnt . The signal generator 5 transmits a voltage value of V _nt , which is 1/2 of the voltage of 2 V _nt , to the arithmetic unit 8. The measuring instrument 1 measures the voltage V _mt generated in the resistance 6 by using the probe 11 connected to the measuring instrument 1 (see FIG. 5). The measuring instrument 1 transmits the measurement result of the voltage V _mt to the arithmetic unit 8. The arithmetic unit 8 stores the voltage V _nt and the voltage V _mt .

Step S103;
Next, the arithmetic unit 8 substitutes the voltage V _nt and the voltage V _mt into the equation (6) for calculating the ground capacitance C _m , and solves the problem, so that the conductor is connected to the ground line of the measuring instrument 1. Obtain the ground capacity C _m of the plate. Note that Z _m is the input impedance of the measuring instrument 1 including the probe 11, and is a value described in the data sheet of the measuring instrument 1 and the probe 11.

After that, the arithmetic unit 8 generates a list in which the voltage _Vr of the correction device 2 and the ground capacitance _Cm of the conductor plate connected to the ground line of the measuring instrument 1 are related. If the list has already been generated, the arithmetic unit 8 adds the correspondence between the voltage _Vr and the ground capacitance _Cm to the next line of the list.

Step S104;
Next, the arithmetic unit 8 or the measurer determines whether or not the above measurement has been performed for the thicknesses of all the dielectric plates 4. If the above measurement has not been performed for the thicknesses of all the dielectric plates 4, the process proceeds to step S105. When the above measurement is performed for the thicknesses of all the dielectric plates 4, the process ends.

Step S105;
Next, the arithmetic unit 8 or the measurer changes the thickness of the dielectric plate 4. Then, the process returns to step S101.

After that, steps S101 to S103 are repeatedly executed while changing the thickness of the dielectric plate 4. As a result, the arithmetic unit 8 can list the correspondence between the voltage _Vr and the ground capacitance Cm according to the thickness of the dielectric plate 4. As a method of changing the thickness of the dielectric plate 4, for example, there are a method of manually changing the thickness of the dielectric plate 4 and a method of automatically connecting the link mechanism to the arithmetic unit 8.

Next, the measurement work at the measurement location of electromagnetic noise will be explained.

FIG. 7 is a diagram showing a processing flow of measurement work at the measurement location in Example 1. At the measurement location of electromagnetic noise, the measuring instrument 1, the conductor plate 7, the correction device 2, and the arithmetic unit 8 are installed in the same manner as in FIG. The dielectric plate 4 of FIG. 5 serves as a measurement location for electromagnetic noise.

Step S201;
First, the correction device 2 measures the voltage _Vr at the measurement location of the electromagnetic noise. The correction device 2 transmits the measurement result of the voltage _Vr to the arithmetic unit 8.

Step S202;
Next, the arithmetic unit 8 has a ground capacitance C of the conductor plate connected to the ground line of the measuring instrument 1 corresponding to the voltage _Vr of the correcting device 2 at the measurement location of the electromagnetic noise from the list created in advance. Select _m .

Step S203;
Next, the measuring instrument 1 measures the ground voltage _Vm of the electromagnetic noise at the measurement location of the electromagnetic noise. The measuring instrument 1 transmits the measurement result of the voltage to ground V _m to the arithmetic unit 8.

Step S204;
Finally, the correction device 2 obtains the ground voltage V _n of the electromagnetic noise by substituting the ground capacitance C _m and the ground voltage V _m into the equation (3) and solving the problem. That is, the ground voltage V _m of the electromagnetic noise with an error measured by the measuring instrument 1 is corrected to the ground voltage V _n of the electromagnetic noise to be measured. The voltage V _n to ground of the electromagnetic noise is displayed on the monitor on the correction device 2. At this time, V _n may be displayed as the intensity for each frequency, or may be displayed as a waveform of electromagnetic noise. This is because the correction is performed using the ground capacitance _Cm , so that not only the intensity but also the phase information can be corrected.

[Example 2]
Next, Example 2 will be described.

The second embodiment is different from the first embodiment in that the correction coefficient X is obtained instead of finding the correspondence between the voltage _Vr and the ground capacitance Cm in the preliminary work. Further, unlike the first embodiment, the signal generator 5 outputs a sine wave having M kinds of frequencies from the angular frequency ω _{nt 1} to the angular frequency ω _nt M, instead of a single frequency. The magnitude of the voltage output from the signal generator 5 is constant at 2 _Vnt as in the first embodiment. The overall configuration of the measurement system and the mechanisms of the measuring instrument 1 and the correction device 2 are the same as those in the first embodiment. Hereinafter, the preliminary work will be described.

FIG. 8 is a diagram showing a processing flow of the preliminary work in the second embodiment.

Step S301;
First, the correction device 2 measures the voltage _Vr . The correction device 2 transmits the measurement result of the voltage _Vr to the arithmetic unit 8. The arithmetic unit 8 stores the measurement result of the voltage _Vr .

Step S302;
Next, the signal generator 5 outputs a sine wave having a voltage of 2 V _nt and an angular frequency of ω nt _{k (k = 1)} . The signal generator 5 transmits a voltage value of V _nt , which is 1/2 of the voltage of 2 V _nt , to the arithmetic unit 8. The measuring instrument 1 measures the voltage V _{mtk (k = 1)} generated in the resistor 6 by using the probe 11 connected to the measuring instrument 1. The measuring instrument 1 transmits the measurement result of the voltage V _{mtk (k = 1)} to the arithmetic unit 8. The arithmetic unit 8 stores the voltage V _nt and the voltage V _{mtk (k = 1)} .

Step S303;
Next, the arithmetic unit 8 calculates the correction coefficient X at the angular frequency ω _{ntk (k = 1)} by substituting the voltage V _nt and the voltage V _{mtk (k = 1)} into the equation (7) and solving the problem. ..

Step S304;
Next, the arithmetic unit 8 determines whether or not k = M. If k = M, the process proceeds to step S305. If k = M, the process proceeds to step S306.

Step S305;
Next, the arithmetic unit 8 sets k = k + 1 and returns to step S302.

After that, the signal generator 5 outputs a sine wave having a voltage of 2 V _nt and an angular frequency of ω nt _{k (k = 2)} . Further, the arithmetic unit 8 calculates the correction coefficient X at the angular frequency ω _{ntk (k = 2)} . This process is repeated until the angular frequency ω _ntk becomes the angular frequency ω _{nt M.}

Step S306;
Next, the arithmetic unit 8 generates a list in which the voltage _{Vr of the correction device 2 and the respective correction coefficients X at each angular frequency ω ntk are} related to each other. If the list has already been generated, the arithmetic unit 8 adds the correspondence between the voltage _{Vr and each correction coefficient X at each angular frequency ω ntk to} the next line of the list.

Step S307;
Next, the arithmetic unit 8 or the measurer determines whether or not the above measurement has been performed for the thicknesses of all the dielectric plates 4. If the above measurement has not been performed for the thicknesses of all the dielectric plates 4, the process proceeds to step S308. When the above measurement is performed for the thicknesses of all the dielectric plates 4, the process ends.

Step S308;
Next, the arithmetic unit 8 or the measurer changes the thickness of the dielectric plate 4. After that, the process returns to step S301.

After that, steps S301 to S306 are repeatedly executed while changing the thickness of the dielectric plate 4. Thereby, in the arithmetic unit 8, the correspondence relationship between the voltage Vr and the respective correction coefficients X at each angular frequency ω _ntk can be listed in the thickness of the dielectric plate 4.

Next, the measurement work at the measurement location of electromagnetic noise will be explained.

FIG. 9 is a diagram showing a processing flow of measurement work at the measurement location in Example 2.

Step S401;
First, the correction device 2 measures the voltage _Vr at the measurement location of the electromagnetic noise. The correction device 2 transmits the measurement result of the voltage _Vr to the arithmetic unit 8. The voltage _{Vr can be decomposed for each angular frequency ω ntk .}

Step S402;
Next, the correction device 2 selects all M correction coefficients X corresponding to the voltage _Vr of the correction device 2 at the measurement location of the electromagnetic noise from the list created in advance.

Step S403;
Next, the measuring instrument 1 measures the ground voltage _Vm of the electromagnetic noise at the measurement location of the electromagnetic noise. The measuring instrument 1 transmits the measurement result of the voltage to ground V _m to the arithmetic unit 8.

Step S404;
Finally, the correction device 2 substitutes each correction coefficient X and the ground voltage V _m into the equation (4) and solves them to obtain the ground voltage V _n of the electromagnetic noise at each angular frequency ω _ntk . That is, the ground voltage V _m of the electromagnetic noise with an error measured by the measuring instrument 1 is corrected to the ground voltage V _n of the electromagnetic noise to be measured. The voltage V _n to ground of the electromagnetic noise is displayed on the monitor on the correction device 2. At this time, V _n is displayed as the intensity for each frequency.

As described above, the measurement method invented this time enables accurate measurement even when the measurement location and the ground are far apart when measuring the voltage to ground of electromagnetic noise in a non-grounded state. The reason for this is that the correction list is created in advance without using the equation (1), which is a premise of the prior art.

[Effect of Examples]
In the first embodiment, in the preliminary work, a list for correction is created in which the ground capacitance _Cm of the conductor plate 7 connected to the ground line of the measuring instrument 1 is associated with the measurement result of the correction device 2 at the measurement site. In, using this list, the ground capacitance _Cm of the conductor plate 7 connected to the ground line of the measuring instrument 1 is obtained from the measurement result of the correction device 2, and the electromagnetic wave measured by the measuring instrument 1 at the ground capacitance _Cm . The method of correcting the noise to ground voltage V _m has been described.

In the second embodiment, in the preliminary work, the correction coefficient X capable of obtaining the ground voltage V _n of the measurement target by multiplying the ground voltage V _m of the electromagnetic noise measured by the measuring instrument 1 is used as the measurement result of the correction device 2. A list for associated correction is created, and at the measurement site, the correction coefficient X is obtained from the measurement result of the correction device 2 at the measurement site, and the electromagnetic noise measured by the measuring instrument 1 with the correction coefficient X is obtained. The method of correcting the ground voltage V _m has been described.

The method of Example 2 has higher measurement accuracy than that of Example 1 because the data of all frequency bands to be measured is acquired in advance. On the other hand, in the first embodiment, since it is only necessary to acquire the data of a single frequency in the preliminary work, the time required for the preliminary work can be shortened as compared with the second embodiment, and further, not only the intensity but also the phase correction can be performed. Since it is possible, it is possible to display the measurement result as a waveform.

Based on the above, according to the present embodiment, the measuring instrument 1 for measuring the ground voltage of electromagnetic noise without grounding the ground wire and the self-correcting device used for correcting the error of the ground voltage of the electromagnetic noise. In a measurement system including a correction device 2 that measures a fluctuating voltage that changes according to the magnitude of the ground capacitance, and a calculation device 8 that is communicably connected to the measuring device 1 and the correction device 2, respectively. The calculation device 8 was measured by the correction device 2 every time the thickness of the dielectric plate 4 was changed in a state where the measuring device 1 and the correction device 2 were respectively installed on the dielectric plate 4. Generates a list relating the value of the fluctuating voltage and the value of the correction data measured by the measuring instrument based on the pseudo-electromagnetic noise, which is used to correct the error of the voltage to ground of the electromagnetic noise. In a state where the generation unit 81, the measuring device 1, and the correction device 2 are installed at the measurement locations of electromagnetic noise, the correction data corresponding to the value of the fluctuation voltage measured by the correction device 2 is obtained. Since it is provided with a correction unit 82 that acquires a value from the list and corrects the ground voltage of the electromagnetic noise measured by the measuring instrument 1 with the value of the correction data, the measurement location and the ground where the measuring instrument 1 is installed are provided. It is possible to provide a technique capable of accurately measuring the ground voltage of electromagnetic noise even when the distance between the two and the ground is high.

[others]
The present invention is not limited to the above embodiment. The present invention can be modified in a number of ways within the scope of the gist of the present invention.

As shown in FIG. 10, the arithmetic unit 8 of the present embodiment described above includes, for example, a CPU (Central Processing Unit, processor) 901, a memory 902, and a storage (HDD: HardDiskDrive, SSD: SolidStateDrive). It can be realized by using a general-purpose computer system including a 903, a communication device 904, an input device 905, and an output device 906. The memory 902 and the storage 903 are storage devices. In the computer system, each function of the arithmetic unit 8 is realized by the CPU 901 executing a predetermined program loaded on the memory 902.

The arithmetic unit 8 may be mounted on one computer. The arithmetic unit 8 may be implemented by a plurality of computers. The arithmetic unit 8 may be a virtual machine mounted on a computer. The program for the arithmetic unit 8 can be stored in a computer-readable recording medium such as an HDD, SSD, USB (Universal Serial Bus) memory, CD (Compact Disc), or DVD (Digital Versatile Disc). The program for the arithmetic unit 8 can also be distributed via the communication network.

1: Measuring instrument 11: Probe 2: Correcting device 21: Voltage measuring circuit 22: Oscillation circuit 23a: First electrode 23b: Second electrode 23c: Third electrode 24a: First spacer 24b: Second spacer 3: Shielded room floor 4: Dielectric plate 5: Signal generator 6: Resistance 7: Conductor plate 8: Arithmetic device 81: Generation unit 82: Correction unit 83: Storage unit 901: CPU
902: Memory 903: Storage 904: Communication device 905: Input device 906: Output device

Claims (5)

A measuring instrument that measures the ground voltage of electromagnetic noise without grounding the ground wire, and a fluctuation that changes according to the magnitude of the ground capacitance of the self-correcting device, which is used to correct the error of the ground voltage of the electromagnetic noise. In a measurement system including a correction device for measuring a voltage and a calculation device communicably connected to the measuring device and the correction device, respectively.
The arithmetic unit is
In a state where the measuring instrument and the compensator are respectively installed on the dielectric plate, each time the thickness of the dielectric plate is changed, the value of the fluctuating voltage measured by the compensator and the electromagnetic noise A generator that is used to correct the error of the voltage to ground and generates a list relating the value of the correction data measured by the measuring instrument based on the pseudo-electromagnetic noise.
In a state where the measuring instrument and the compensator are installed at the measurement locations of electromagnetic noise, the values of the compensating data corresponding to the values of the fluctuating voltage measured by the compensator are acquired from the list. A correction unit that corrects the ground voltage of electromagnetic noise measured by the measuring instrument with the value of the correction data, and a correction unit.
A measurement system equipped with. The correction data is
The measuring system according to claim 1, which is the ground capacitance of the conductor plate connected to the ground wire of the measuring instrument and installed on the dielectric plate. The correction data is
The measurement system according to claim 1, which is a correction coefficient capable of obtaining the ground voltage of the corrected electromagnetic noise by multiplying the ground voltage of the electromagnetic noise measured by the measuring instrument. The correction coefficient is
The measuring system according to claim 3, which is a ratio of the voltage of the pseudo-electromagnetic noise output from the signal generator to the voltage of the pseudo-electromagnetic noise measured by the measuring instrument. A measuring instrument that measures the ground voltage of electromagnetic noise without grounding the ground wire, and a fluctuation that changes according to the magnitude of the ground capacitance of the self-correcting device, which is used to correct the error of the ground voltage of the electromagnetic noise. In a measurement method performed by using a correction device for measuring a voltage and a calculation device communicably connected to the measuring device and the correction device, respectively.
The arithmetic unit is
In a state where the measuring instrument and the compensator are respectively installed on the dielectric plate, each time the thickness of the dielectric plate is changed, the value of the fluctuating voltage measured by the compensator and the electromagnetic noise A step of generating a list relating the value of the correction data measured by the measuring instrument based on the pseudo-electromagnetic noise, which is used to correct the error of the voltage to ground.
In a state where the measuring instrument and the compensator are installed at the measurement locations of electromagnetic noise, the values of the compensating data corresponding to the values of the fluctuating voltage measured by the compensator are acquired from the list. A step of correcting the ground voltage of electromagnetic noise measured by the measuring instrument with the value of the correction data, and
Measurement method to perform.

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