Anomaly diagnosis device and anomaly diagnosis method

Abstract

To provide an abnormality diagnosis device that can conduct abnormality diagnosis of a motor without performing settings of a number of parameters.SOLUTION: An abnormality diagnosis device 40 comprises: a current measurement unit 410 that measures a load current of a motor 20; a frequency analysis unit 411 that performs frequency analysis of the load current; and a deterioration degree calculation unit 412 that adds up, within a preset frequency range, a preset number of intensity values from the top rank to calculate a degree of deterioration.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] This invention relates to an abnormality diagnosis device and an abnormality diagnosis method.

Background Art

[0002] Conventionally, diagnosing an abnormality in a motor with load imbalance has been performed by analyzing the FFT waveform of the drive current of the motor and detecting sideband waves that vary due to the abnormality.

[0003] For example, in Patent Document 1, abnormality diagnosis of a motor is performed by calculating the difference between the power supply frequency level and the side wave level of the rotation frequency of the motor.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, in the method of Patent Document 1, many parameters are required to specify the frequency band in which an abnormality appears, and the setting is time-consuming. For example, when calculating the rotation frequency of the motor, many parameters such as the drive frequency of the motor, the number of poles of the motor, and slip need to be set.

[0006] This invention has been made to solve the above problems, and an object thereof is to provide an abnormality diagnosis device capable of diagnosing an abnormality of a motor without setting many parameters.

Means for Solving the Problems

[0007] One aspect of the abnormality diagnosis device in the present invention is a current measurement unit that measures the load current of the motor, A frequency analysis unit that performs frequency analysis on the load current, The system includes a degradation degree calculation unit that calculates the degree of degradation by summing a predetermined number of intensity values ​​from the highest to the lowest within a predetermined frequency range.

[0008] Furthermore, one embodiment of the abnormality diagnosis method in the present invention is: The current measurement unit measures the load current of the motor, and The frequency analysis unit performs a frequency analysis on the load current, The system includes a step of calculating the degree of degradation by summing a predetermined number of intensity values ​​from the highest to lowest within a predetermined frequency range using a degradation degree calculation unit. [Effects of the Invention]

[0009] According to the present invention, it is possible to provide a malfunction diagnosis device that can diagnose motor malfunctions without setting many parameters. [Brief explanation of the drawing]

[0010] [Figure 1] This figure shows a schematic configuration of an abnormality diagnosis system according to one embodiment of the present invention. [Figure 2] This is a block diagram showing the hardware configuration of the anomaly diagnosis device. [Figure 3] (A) is a figure showing an example of the original FFT waveform of the drive current in a motor with load imbalance, and (B) is a figure showing an example of the waveform after removing the DC component and harmonics from the FFT waveform in (A). [Figure 4] This flowchart shows the process for calculating the degree of deterioration using an abnormality diagnosis device. [Figure 5] This diagram shows the load current when the motor is functioning normally and when an imbalance occurs. [Figure 6] This diagram shows the load current when the motor is functioning normally and when a malfunction occurs due to cavitation. [Figure 7] This diagram shows the load current when the motor is functioning normally and when a malfunction occurs due to bearing deterioration. [Figure 8] This is a diagram showing a state where noise due to the influence of inverter drive and minute noise generated by other factors are present in the signal to be detected. [Figure 9] This is a flowchart showing the deterioration degree calculation process by the abnormality diagnosis device of the second embodiment. [Figure 10] This is a diagram showing the load current when the motor is normal and when an abnormality due to unbalance occurs.

Mode for Carrying Out the Invention

[0011] Hereinafter, embodiments of this invention will be described in detail with reference to the drawings. (First Embodiment) First, the first embodiment of this invention will be described in detail with reference to the drawings. FIG. 1 is a diagram showing the schematic configuration of the abnormality diagnosis system 100 according to this embodiment. As shown in FIG. 1, the abnormality diagnosis system 100 includes a current sensor 30, an abnormality diagnosis device 40, and a dedicated tool 50. The abnormality diagnosis system 100 is a system for diagnosing abnormalities of the motor 20 connected to the inverter 10.

[0012] The inverter 10 is connected to a three-phase power supply and combines an AC-DC converter that converts three-phase alternating current into direct current and a DC-AC inverter to convert three-phase alternating current into an arbitrary frequency and voltage. By using the inverter 10, it is possible to change the phase and frequency of the drive current in accordance with the rotational position of the rotor of the motor 20, thereby realizing high drive efficiency and smooth rotation with little vibration from low speed to high speed. Note that the inverter 10 is not an essential component, and the abnormality diagnosis system 100 of this embodiment can also be realized in a configuration without the inverter 10.

[0013] The motor 20 is a three-phase motor and is driven by three-phase alternating current from the inverter 10. The motor 20 includes a stator and a rotor (not shown). The rotor rotates a rotating shaft supported by bearings.

[0014] The current sensor 30 is a sensor that measures the load current of the motor 20. The current sensor 30 is connected to the abnormality diagnosis device 40, and the load current of the motor 20 measured by the current sensor 30 is input to the abnormality diagnosis device 40.

[0015] The abnormality diagnosis device 40 includes a current measurement unit that measures the load current of the motor 20, a frequency analysis unit that performs frequency analysis on the load current, and an abnormality determination unit that calculates a degradation degree by summing a preset number of intensity values from the top within a preset frequency range. Details of the abnormality diagnosis device 40 will be described later.

[0016] The dedicated tool 50 is a device connected to the abnormality diagnosis device 40 via a LAN or the like, and is composed of, for example, a personal computer or the like. By connecting the dedicated tool 50 to the abnormality diagnosis device 40, it becomes possible to monitor the state of the motor 20. Note that the dedicated tool 50 is not an essential component, and the abnormality diagnosis system 100 of the present embodiment can be realized even in a configuration without the dedicated tool 50.

[0017] Fig. 2 shows the hardware configuration of the abnormality diagnosis device 40. As shown in Fig. 2, the abnormality diagnosis device 40 includes an arithmetic unit 41, an EIP port 42, a display unit 43, an output contact 44, and a power supply circuit 45.

[0018] The arithmetic unit 41 has the functions of an AD conversion unit 410, an FFT analysis unit 411, a degradation degree calculation unit 412, and an abnormality determination unit 413. The AD conversion unit 410 functions as a current measurement unit that AD-converts the load current of the motor 20 detected by the current sensor 30. The FFT analysis unit 411 functions as a frequency analysis unit that performs frequency analysis on the load current. The degradation degree calculation unit 412 calculates the degradation degree by summing a preset number of intensity values from the top within a preset frequency range. The abnormality determination unit 413 has the function of an input unit that inputs a threshold value and the function of an abnormality determination unit that determines whether the motor 20 has deteriorated by comparing the input threshold value with the degradation degree. The threshold value is input, for example, from the dedicated tool 50.

[0019] EIP port 42 is a port that enables communication between the anomaly diagnosis device 40 and the dedicated tool 50 using the EtherNet / IP network protocol.

[0020] The display unit 43 is composed of, for example, electronic paper and displays the degree of deterioration calculated by the abnormality diagnosis device 40.

[0021] The output contact 44 is a contact for transmitting the output of the abnormality diagnosis device 40 to an external device.

[0022] The power supply circuit 45 is connected to an external power supply and is a circuit that supplies the power necessary for the operation of each part of the abnormal diagnosis device 40.

[0023] (Methods for diagnosing abnormalities) Figure 3(A) shows an example of the original FFT waveform of the drive current in a motor with load imbalance, and Figure 3(B) shows an example of the waveform after removing the DC component and harmonics from the FFT waveform in (A).

[0024] In this embodiment, DC components and harmonics that do not cause abnormalities in the motor 20 are removed from the FFT waveform of the drive current of the motor 20, and a preset number of data points are summed up. This eliminates the need for setting up sidebands and makes it possible to identify deterioration and failure of the motor 20.

[0025] For example, in the FFT waveform of the drive current of motor 20 experiencing a load imbalance as shown in Figure 3(A), the DC component and harmonics fluctuate significantly. Therefore, when the amplitudes are added together, the sum of the values ​​fluctuates due to factors other than the motor 20 malfunction. Consequently, conventionally, it was necessary to identify the frequency obtained by adding the rotation frequency to the power supply frequency, and the frequency obtained by subtracting the rotation frequency from the power supply frequency.

[0026] However, in this embodiment, as shown in Figure 3(B), by removing the DC component and harmonics, the changes in frequency components (= power supply frequency ± rotation frequency) caused by the abnormality of the motor 20 become more pronounced, and the abnormality of the motor 20 can be quantified simply by summing the amplitudes.

[0027] (Processing of abnormality diagnosis) Figure 4 is a flowchart showing the degradation degree calculation process by the abnormality diagnosis device 40 of this embodiment. First, the AD conversion unit 410 of the abnormality diagnosis device 40 acquires the load current of the motor 20 using the current sensor 30 (Figure 4: S1).

[0028] Next, the FFT analysis unit 411 of the anomaly diagnosis device 40 performs frequency analysis of the load current using the discrete Fourier transform (Figure 4: S2).

[0029] Next, the degradation degree calculation unit 412 of the abnormality diagnosis device 40 cuts out the fundamental wave and harmonics from the current data (Figure 4: S3).

[0030] Next, the degradation degree calculation unit 412 of the abnormality diagnosis device 40 calculates the degradation degree by summing a predetermined number of intensity values ​​from the highest to lowest (Figure 4: S4). Specifically, the degradation degree calculation unit 412 calculates the degradation degree by summing the intensity values ​​of, for example, the top 10 noises, dividing this summed intensity value by all signal values, and multiplying it by a coefficient to adjust the sensitivity. The formula for calculating the degradation degree is shown in (Equation 1).

[0031] (Math 1) In the above formula TIFF0007900895000001.tif1870, N represents the number of data points to be added, and A represents the coefficient for adjusting the sensitivity.

[0032] After this, the abnormality determination unit 413 of the abnormality diagnosis device 40 may perform an abnormality determination by comparing the threshold value with the calculated degree of deterioration.

[0033] (Calculation process for degree of deterioration) Next, the process for calculating the degree of degradation in this embodiment will be described. In the following example, the motor 20 has 4 poles and is driven directly with a power supply frequency of 60 Hz.

[0034] The abnormalities of the motor 20 manifest differently depending on the failure mode. Therefore, this embodiment provides three methods for calculating the degree of degradation, tailored to the specific failure mode.

[0035] The first failure mode is due to unbalance, misalignment, or rotor bar breakage. The second failure mode is due to cavitation. The third failure mode is due to bearing degradation. The calculation process for the degree of degradation in each failure mode is described below.

[0036] (First failure mode) As an example, we will explain the process for calculating the degree of degradation in the case of a failure mode due to imbalance. Figure 5 shows the load current when the motor 20 is functioning normally and when an abnormality occurs due to imbalance.

[0037] In this example, the FFT analysis unit 411 performed an FFT with a resolution of 0.25 Hz, and the 10 highest intensity values ​​in the frequency range from 0 Hz to the second harmonic (0 Hz to 120 Hz) were summed up to calculate the degree of degradation using the following formula.

[0038] (Math 2) TIFF0007900895000002.tif21106

[0039] However, the top 10 is just an example; you can simply add up the intensity values ​​of 6 to 20 items.

[0040] As can be seen from Figure 5, in this case, the intensity values ​​of the fundamental frequency ± rotation frequency increase, and under the conditions of this example, in the case of an abnormality, the intensity values ​​of 30 Hz and 90 Hz increase. Also, in this case, the degradation degree in the normal case was 13, and the degradation degree in the abnormal case was 22. Therefore, by setting the threshold to 20, the abnormality detection unit 413 can determine that there is an abnormality.

[0041] (Second failure mode) As an example, we will explain the process for calculating the degree of degradation in the case of a failure mode caused by cavitation. Figure 6 shows the load current when the motor 20 is functioning normally and when an abnormality occurs due to cavitation.

[0042] In this example, the FFT analysis unit 411 performed an FFT with a resolution of 0.25 Hz, and the degradation degree was calculated by summing the top 60 intensity values ​​in the frequency range of the fundamental frequency ± 15 Hz, using the following formula.

[0043] (Math 3) TIFF0007900895000003.tif2089

[0044] However, the top 60 is just an example; you can change the number of items as needed and sum up the intensity values.

[0045] As can be seen from Figure 6, in this case, the intensity values ​​within ±15Hz of the fundamental frequency increase, and in the case of an abnormality, the intensity values ​​between 45Hz and 75Hz increase. Also, in this case, the degradation level was 13 in the normal case and 30 in the abnormal case. Therefore, by setting the threshold to 20, the abnormality detection unit 413 can detect an abnormality.

[0046] (Third failure mode) As an example, we will explain the process for calculating the degree of deterioration in the case of a failure mode due to bearing deterioration. Figure 7 shows the load current when the motor 20 is functioning normally and when an abnormality occurs due to bearing deterioration.

[0047] In this example, the FFT analysis unit 411 performed an FFT with a resolution of 0.25 Hz, and the degradation level was calculated by summing the top 4000 intensity values ​​in the frequency range from the 2nd harmonic to the 20th harmonic (120 Hz to 1200 Hz) using the following formula.

[0048] (Math 4) TIFF0007900895000004.tif20107

[0049] However, the top 4000 is just one example; you can change the number of items as needed and sum up the intensity values.

[0050] As can be seen from Figure 7, in this case, the intensity values ​​of the 2nd to 20th harmonics increase, and under the conditions of this example, in the case of an abnormality, the intensity values ​​of 120Hz to 1200Hz increase. Also, in this case, the degradation degree in the normal case was 20, and the degradation degree in the abnormal case was 30. Therefore, by setting the threshold to 25, the abnormality detection unit 413 can determine that an abnormality has occurred.

[0051] As described above, according to this embodiment, the degree of deterioration is calculated by summing up a predetermined number of intensity values ​​from the highest to the lowest within a predetermined frequency range. Therefore, it is possible to diagnose motor abnormalities without having to set many parameters such as the motor drive frequency, the number of motor poles, and slip.

[0052] (Second Embodiment) Next, a second embodiment of this invention will be described in detail with reference to the drawings. Figure 8 is a diagram showing the state in this embodiment where the signal to be detected is affected by noise due to the inverter drive and minute noise caused by other factors. Figure 9 is a flowchart showing the degradation degree calculation process by the abnormality diagnosis device of this embodiment. Figure 10 is a diagram showing the load current in this embodiment when the motor is normal and when an abnormality occurs due to imbalance.

[0053] In the first embodiment described above, a method was described in which the degree of deterioration is calculated by summing a predetermined number of strength values ​​from the highest to the lowest. On the other hand, in this embodiment, a method is described in which the degree of deterioration is calculated by summing strength values ​​above a certain level.

[0054] As shown in Figure 8, the inverter drive can sometimes generate noise that is larger than the signal to be detected. In Figure 8, arrow A indicates the noise caused by the inverter drive.

[0055] In this case, for example, if the intensity values ​​are summed up using only a small number of values, such as the top 10, the top 10 may contain a large amount of noise due to the inverter's influence, which can reduce the sensitivity for detecting signals caused by abnormalities.

[0056] The noise intensity due to inverter drive varies depending on the inverter's control method and manufacturer, so it cannot be uniformly removed. Therefore, instead of summing a fixed number of intensity values ​​from the highest level, it is possible to sum a larger number of intensity values.

[0057] However, as shown in Figure 8, in addition to noise caused by inverter drive, there is also minute noise caused by other factors. Figure 8 shows a state in which the signal to be detected is affected by noise caused by inverter drive and minute noise caused by other factors. In Figure 8, arrow C indicates minute noise caused by other factors. The intensity values ​​of this minute noise are highly random, and if many intensity values ​​are added together, the signal may contain a large amount of minute noise, potentially reducing the sensitivity to detect signals caused by anomalies.

[0058] Therefore, in this embodiment, signals below a certain level are removed, and the intensity values ​​above a certain level are summed to calculate the degree of degradation. However, experimental results have shown that noise due to anomalies has an intensity value of -50 dB or higher. Therefore, in this embodiment, for example, a margin of -10 dB is taken, and intensity values ​​of -60 dB or higher are summed to remove minute noise, and then all remaining signals are summed. As a result, it was confirmed that the signals to be detected can be reliably summed after removing minute noise, and the degradation trend can be detected.

[0059] Noise generated by inverter drive remains constant regardless of the abnormality, but the signal to be detected changes depending on the abnormality. However, according to this embodiment, by summing up intensity values ​​above a certain level, a sufficient number of intensity values ​​for the signal to be detected can be obtained, thereby preventing a decrease in sensitivity to detect signals due to abnormalities.

[0060] The hardware configuration of the anomaly diagnosis device 40 in this embodiment is the same as that of the anomaly diagnosis device 40 in the first embodiment shown in Figure 2, when shown in a block diagram. However, the anomaly diagnosis device 40 in this embodiment does not calculate the degree of deterioration by summing up a number of intensity values ​​set in advance from higher levels, but rather calculates the degree of deterioration by summing up intensity values ​​that are above a predetermined level.

[0061] The abnormality diagnosis device 40 of this embodiment includes a calculation unit 41, an EIP port 42, a display unit 43, an output contact 44, and a power supply circuit 45, similar to the first embodiment. The degradation degree calculation unit 412 in this embodiment differs from the first embodiment in that it calculates the degradation degree by summing up intensity values ​​above a certain level within a preset frequency range. The other configurations are the same as in the first embodiment.

[0062] (Processing of abnormality diagnosis) Figure 9 is a flowchart showing the degradation degree calculation process by the abnormality diagnosis device 40 of this embodiment. First, the AD conversion unit 410 of the abnormality diagnosis device 40 acquires the load current of the motor 20 using the current sensor 30 (Figure 9: S10).

[0063] Next, the FFT analysis unit 411 of the anomaly diagnosis device 40 performs frequency analysis of the load current using the discrete Fourier transform (Figure 9: S11).

[0064] Next, the degradation level calculation unit 412 of the abnormality diagnosis device 40 cuts out the fundamental wave and harmonics from the current data, and further cuts out noise below a certain level (Figure 9: S12).

[0065] Next, the degradation degree calculation unit 412 of the abnormality diagnosis device 40 calculates the degradation degree by summing a predetermined number of intensity values ​​from the highest level (Figure 9: S13). Specifically, the degradation degree calculation unit 412, for example, removes noise below -60 dB, sums the intensity values ​​of all remaining noise, divides this summed intensity value by all signal values, and multiplies it by a coefficient for adjusting sensitivity to calculate the degradation degree. The formula for calculating the degradation degree is the same as the formula shown in (Equation 1) described in the first embodiment.

[0066] After this, the abnormality determination unit 413 of the abnormality diagnosis device 40 may perform an abnormality determination by comparing the threshold value with the calculated degree of deterioration.

[0067] (Calculation process for degree of deterioration) Next, the process for calculating the degree of degradation in this embodiment will be described. In the following example, the motor 20 has 4 poles and is driven directly with a power supply frequency of 60 Hz.

[0068] In this embodiment, as an example, the process for calculating the degree of degradation in the case of a failure mode due to imbalance will be described. Figure 10 shows the load current when the motor 20 is functioning normally and when an abnormality occurs due to imbalance.

[0069] In this example, the FFT analysis unit 411 performed an FFT with a resolution of 0.25 Hz, and the intensity values ​​of -60 dB or higher in the frequency range from 0 Hz to the second harmonic (0 Hz to 120 Hz) were summed up to calculate the degree of degradation using the following formula.

[0070] (Math 5) TIFF0007900895000005.tif21104

[0071] As can be seen from Figure 10, in this case, the intensity values ​​of the fundamental frequency ± rotation frequency increase, and under the conditions of this example, in the case of an abnormality, the intensity values ​​of 30 Hz and 90 Hz increase. Also, in this case, the degradation degree in the normal case was 24, and the degradation degree in the abnormal case was 33. Therefore, by setting the threshold to 30, the abnormality detection unit 413 can detect an abnormality.

[0072] This embodiment may be combined with the first embodiment. When this embodiment is combined with the first embodiment, the abnormality diagnosis device 40, in particular the degradation degree calculation unit 412, may be provided with a function to calculate the degradation degree by summing up a predetermined number of intensity values ​​from the highest to the lowest for intensity values ​​above a certain level within a predetermined frequency range.

[0073] (modified version) The embodiments described above are illustrative and various modifications are possible without departing from the scope of this invention.

[0074] In the embodiments described above, a method was described in which the load current waveforms output over a 4-second period are summed up every 4 seconds. However, the present invention is not limited to this embodiment, and the summing period can be appropriately determined in consideration of the balance between the amount of data and the accuracy.

[0075] This specification has described an abnormality diagnosis device and an abnormality diagnosis method according to embodiments of the present invention, but the present invention is not limited thereto, and various modifications are possible without departing from the spirit of the invention. [Explanation of symbols]

[0076] 10 Inverters 20 motors 30 Current Sensor 40. Anomaly Diagnosis Device 41 Arithmetic section 42 EIP ports 43 Display section 44 output contacts 50 Dedicated Tools 100 Anomaly Diagnosis Systems 410 AD Conversion Unit 411 FFT analysis section 412 Deterioration degree calculation section 413 Abnormality determination section

Claims

1. A frequency analysis unit that performs frequency analysis on the motor load current, A degradation degree calculation unit includes a summing means that sums the noise intensity values ​​from the highest to the Nth rank (where N is one of 6 to 20) within a predetermined frequency range without summing all noise intensity values, and a calculation means that calculates the degree of degradation using the sum obtained by the summing means. An abnormality determination unit determines that the motor has an abnormality due to unbalance, misalignment, or breakage of the rotor bar by comparing the degree of deterioration with a pre-selected threshold, Equipped with, An abnormality diagnosis device characterized by the following features.

2. The motor is further equipped with a current measuring unit for measuring the load current of the motor, The abnormality diagnosis device according to claim 1, wherein the frequency analysis unit performs frequency analysis on the load current measured by the current measurement unit.

3. The summing means sums the intensity values ​​of the top 10 noises. An abnormality diagnosis device according to claim 1 or 2.

4. The frequency analysis unit performs frequency analysis with a resolution of 0.25 Hz. The summing means sums the noise intensity values ​​in the frequency range from 0 Hz to the second harmonic. An abnormality diagnosis device according to any one of claims 1 to 3.

5. The frequency analysis unit performs frequency analysis with a resolution of 0.25 Hz. The summing means sums the noise intensity values ​​within a frequency range of the fundamental frequency ± 15 Hz. An abnormality diagnosis device according to any one of claims 1 to 3.

6. A frequency analysis unit that performs frequency analysis on the motor load current, A degradation degree calculation unit includes a summing means that sums the intensity values ​​of the top 60 noises within a predetermined frequency range without summing all noise intensity values, and a calculation means that calculates the degree of degradation using the sum obtained by the summing means. An abnormality determination unit determines that the motor has an abnormality due to cavitation by comparing the degree of deterioration with a predetermined threshold, Equipped with, The frequency analysis unit performs frequency analysis with a resolution of 0.25 Hz. The summing means sums the noise intensity values ​​within a frequency range of the fundamental frequency ± 15 Hz. An abnormality diagnosis device characterized by the following features.

7. The frequency analysis unit performs frequency analysis with a resolution of 0.25 Hz. The summing means sums the noise intensity values ​​in the frequency range from the 2nd harmonic to the 20th harmonic. An abnormality diagnosis device according to any one of claims 1 to 2.

8. The summing means excludes the intensity values ​​at the fundamental frequency and harmonics from the summation. An abnormality diagnosis device according to any one of claims 1 to 7.

9. The frequency analysis unit performs a frequency analysis of the motor's load current, The degradation degree calculation unit, which includes an aggregation means and a calculation means, performs the step of aggregating the noise intensity values ​​from the highest to the Nth rank (where N is one of 6 to 20) within a preset frequency range, without aggregating all noise intensity values. The steps include: calculating the degree of deterioration using the sum obtained by the summing means of the deterioration degree calculation unit, which includes an aggregation means and a calculation means; The steps include comparing the degree of degradation with a predetermined threshold, The comparison results include a step of determining whether the motor has an abnormality due to unbalance, misalignment, or breakage of the rotor bar, Equipped with, A method for diagnosing abnormalities characterized by the following features.

10. The frequency analysis unit performs a frequency analysis of the motor's load current, The degradation degree calculation unit, which includes an aggregation means and a calculation means, performs the step of aggregating the noise intensity values ​​from the top 60 within a preset frequency range without aggregating all noise intensity values, The steps include: calculating the degree of deterioration using the sum obtained by the summing means of the deterioration degree calculation unit, which includes an aggregation means and a calculation means; The steps include comparing the degree of degradation with a predetermined threshold, The comparison results include a step of determining that the motor has an abnormality due to cavitation, Equipped with, A method for diagnosing abnormalities characterized by the following features.

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