JP2023172529A - measuring device - Google Patents

Abstract

To provide a technique for contributing to automatic detection of abnormality in a measuring device.SOLUTION: A storage part 14 stores adjustment values obtained by acoustic calibration at different points of time so as to adjust an individual difference in sensitivity of a microphone 11. A control part 13 determines that there is abnormality (S19) when the absolute value of a difference between the current adjustment value A and a previous adjustment value B is equal to or more than a threshold Th1 (S14: No) or the absolute value of a difference between the current adjustment value A and an adjustment value C at the time of manufacture is equal to or more than a threshold Th2 (S17: No) and displays a warning on a display part 15 (S20) while determining that there is no abnormality (S18) when the absolute value of a difference between the current adjustment value A and the previous adjustment value B is smaller than the threshold Th1 (S14: Yes) and the absolute value of a difference between the current adjustment value A and the adjustment value C at the time of manufacture is smaller than the threshold Th2 (S17: Yes). By such determination, abnormality in which microphone sensitivity gradually deviates can also be detected, such that any user can easily recognize that a measuring instrument has a problem.SELECTED DRAWING: Figure 2

Description

The present invention relates to a measuring device for measuring noise, noise exposure, or other measurements related to sound pressure.

When measuring noise, it is required to carry out acoustic calibration of measurement devices such as sound level meters and noise exposure meters before measurement. Sound calibration is usually performed by attaching a sound calibrator that stably generates a reference sound to a microphone of a measuring device, and the measuring device calculates an evaluation value regarding the reference sound input to the microphone. Then, if the evaluation value deviates from a predetermined reference value and the deviation of the evaluation value is within a predetermined range, the evaluation value is adjusted to match the reference value. On the other hand, if the deviation of the evaluation value exceeds a predetermined range, it is determined that there is an abnormality, and the measuring device is not used for measurement.

It is also recommended that acoustic calibration be performed again after measurement. In sound calibration after measurement, it is checked whether the deviation between the evaluation value before measurement and the evaluation value after measurement is within a range that is considered normal. If it exceeds the limit, it is determined that the measuring device is malfunctioning.

However, noise measurements at construction sites, etc. are often carried out by on-site workers who are inexperienced with measurement, and there is a risk of overlooking abnormalities due to mistakes in reading the numbers shown on the measuring device or mistakes due to unfamiliarity. . Regarding such problems, techniques for automating acoustic calibration have been disclosed. (For example, see Patent Documents 1 and 2.).

JP2015-94620A International Publication No. 2005/071371

According to the technique described in Patent Document 2, it is believed that acoustic calibration of a measuring device can be performed without causing human error. However, this technology focuses on automating accurate and reliable acoustic calibration, and cannot detect abnormalities in the microphone. Further, Patent Document 2 discloses recording information regarding a sound calibrator, the date and time of calibration, etc. when performing sound calibration, but does not mention a specific method of using such information.

On the other hand, the technology described in Patent Document 1 calculates the sound pressure threshold from the distribution of the sound pressure level for each frequency component for the signal output by the microphone after sensing the reference sound, and then calculates the sound pressure threshold from the distribution of the sound pressure level for each frequency component and compares it with the previous threshold. This method attempts to determine whether a microphone has malfunctioned, and it is thought that it is possible to detect microphone abnormalities without the occurrence of human error. However, this technique requires complicated processing to obtain a distribution function for each frequency component of the input signal. Furthermore, even with this technique, it is difficult to detect abnormalities that gradually shift over time.

Therefore, an object of the present invention is to provide a technique that contributes to automatic detection of abnormalities in a measuring device.

In order to solve the above problems, the present invention employs the following measuring device. Note that the following words in parentheses are merely examples, and the present invention is not limited thereto.

That is, the measuring device of the present invention is a measuring device for performing noise measurement, noise exposure measurement, or other measurement related to sound pressure, and includes a microphone into which sound is input, and an acoustic measurement device based on a signal corresponding to the sound. A control unit that controls the execution of calibration, and a control unit that is provided inside or connected to the measurement device, and is used as an adjustment value to adjust individual differences in sensitivity of the microphone to perform predetermined calculations or acoustic calibration at the time of manufacturing the measurement device. and a storage section that stores the first adjustment value obtained by the above and the second adjustment value obtained by the previously executed acoustic calibration.

Microphones have individual differences in sensitivity even if they are of the same model. Additionally, the sensitivity of the microphone may gradually shift over time (the relationship between the sensitivity of the microphone and the characteristics of the circuit inside the main unit gradually shifts over time), but such abnormalities are common. It is difficult to detect with standard acoustic calibration.

On the other hand, in the measuring device of the above-mentioned aspect, the storage unit stores predetermined calculations performed at the time of manufacturing the measuring device (calculations based on the characteristics that are individually confirmed for the microphone and the circuit in the main body at the time of manufacturing), Alternatively, the first adjustment value obtained by acoustic calibration performed during manufacturing and the second adjustment value obtained by acoustic calibration performed last time are stored. Therefore, according to the measuring device of the above-described aspect, when the control unit controls the execution of acoustic calibration, by referring to these adjustment values, changes in the adjustment values can be confirmed, and changes in the adjustment values can be confirmed over time. Since it is possible to detect abnormalities that gradually shift, it is possible to contribute to automatic detection of abnormalities in the measuring device.

More preferably, in the measuring device according to the aspect described above, the control unit performs acoustic calibration to obtain the third adjustment value, and determines whether the measuring device is normal based on a comparison between the third adjustment value and the second adjustment value. Determine whether it exists or not.

In the measuring device of this aspect, based on the comparison between the third adjustment value (the adjustment value obtained by the current acoustic calibration) and the second adjustment value (the adjustment value obtained by the previous acoustic calibration), more specific Specifically, the absolute value of the difference between the third adjustment value and the second adjustment value (|third adjustment value - second adjustment value|), or the ratio of the third adjustment value and the second adjustment value (third adjustment value It is determined whether the measuring device is normal depending on whether the adjustment value/second adjustment value) is within the normal range.

More preferably, in the measuring device according to the aspect described above, the control unit further determines whether the measuring device is normal based on a comparison between the third adjustment value and the first adjustment value.

In the measuring device of this aspect, based on the comparison between the third adjustment value (the adjustment value obtained by the current acoustic calibration) and the first adjustment value (the adjustment value obtained by the acoustic calibration during manufacturing), the Specifically, the absolute value of the difference between the third adjustment value and the first adjustment value (|third adjustment value - first adjustment value|), or the ratio of the third adjustment value and the first adjustment value (the 3 adjustment value/first adjustment value) is within the normal range, it is determined whether the measuring device is normal.

Therefore, according to these aspects of the measurement device, abnormalities in the measurement device can be automatically detected because judgments are made objectively based on the results of comparing two adjustment values obtained by acoustic calibration at different times. can be detected. In addition, by issuing a warning when an abnormality is determined, even users who are inexperienced with measurement can easily recognize that there is a problem with the measurement device, so they can use the measurement device without realizing that there is a problem. It is possible to prevent measurement errors that may occur by performing measurements using the .

As described above, according to the present invention, it is possible to contribute to automatic detection of abnormalities in a measuring device.

1 is a block diagram showing the main configuration of a measuring instrument 1. FIG. It is a flowchart which shows the example of the procedure of the 1st form of the process performed with acoustic calibration. It is a flowchart which shows the example of a procedure of the 2nd form of the process performed with acoustic calibration.

Embodiments of the present invention will be described below with reference to the drawings. Note that the following embodiments are preferred examples, and the present invention is not limited to these examples.

[Measuring instrument configuration]
FIG. 1 is a block diagram showing the main configuration of a measuring instrument 1 according to an embodiment.
The measuring instrument 1 includes, for example, a microphone 11, a preamplifier 12, a control section 13, a storage section 14, a display section 15, an operation input section 16, and the like. The measuring device 1 corresponds to, for example, a sound level meter or a noise exposure meter. In other words, the measuring instrument 1 is a device that performs noise measurement, noise exposure measurement, or other measurements related to sound pressure, and whether it is a measuring device (measuring device) or a measuring device (measuring device) depends on It's just a difference in name.

The microphone 11 converts input sound into an electrical signal and outputs it. The preamplifier 12 converts the impedance of the output signal of the microphone 11 as necessary and outputs the signal. The output signal of the preamplifier 12 is input to the control section 13. Note that some MEMS microphones (semiconductor microphones) have a circuit equivalent to a preamplifier built into the MEMS chip, and others output digital signals from the MEMS chip. When such a MEMS microphone is employed as the microphone 11, there is no need to separately provide the preamplifier 12. Therefore, in the following description, signals input from the preamplifier 12 to the control unit 13 and signals input directly from the microphone 11 to the control unit 13 without passing through the preamplifier 12 are collectively referred to as "input signals." In other words, the input signal is a signal input to the control unit 13 in response to the sound input to the microphone 11. The control unit 13 is composed of, for example, a CPU, a DSP (Digital Signal Processor), etc., and calculates a predetermined evaluation value defined by standards, laws, etc. based on the input signal.

By the way, even if the microphones 11 are of the same type, their outputs for sounds of the same intensity vary. Therefore, in the measuring device 1, a coefficient is provided to adjust such variations (individual differences in microphone sensitivity). In the following description, the numerical value of the adjustment coefficient will be referred to as an "adjustment value."

The storage unit 14 is, for example, an internal memory, and stores various threshold values and the like in advance, and also stores adjustment values obtained by adjusting the evaluation values calculated at the time of acoustic calibration. Specifically, the storage unit 14 stores in advance an adjustment value obtained during acoustic calibration during the manufacturing stage of the measuring instrument 1 as an "adjustment value C." Note that when manufacturing the measuring instrument 1, the characteristics of the microphone 11 and the characteristics of the circuits (control unit 13, etc.) installed in the main body are checked individually. What kind of adjustment value will be obtained when this is done can be calculated theoretically based on the characteristics of each component that has been confirmed individually. Therefore, the value obtained by such calculation may be stored in advance as the adjustment value C.

Further, the storage unit 14 stores the adjustment value obtained during the previous acoustic calibration as the "adjustment value B", and also stores the adjustment value changed during execution of the acoustic calibration as the "adjustment value A". Note that when the measuring instrument 1 is shipped, the adjustment value obtained by the acoustic calibration at the time of shipment may be stored as the adjustment value B, or a value calculated based on the adjustment value C or a value obtained by copying the adjustment value C. may be stored as adjustment value B. Further, the values stored as adjustment values A to C may be values in dB according to the evaluation values calculated by the control unit 13, or may be values themselves used in internal calculations (for example, numerical values including decimal points). good.

Along with the acoustic calibration, the control unit 13 uses a plurality of types of adjustment values and threshold values stored in the storage unit 14 to determine whether the measuring device 1 (microphone 11) is normal. The display section 15 is composed of, for example, a liquid crystal screen, a lamp, etc., and displays the evaluation value calculated by the control section 13. Further, if it is determined that there is an abnormality, the display unit 15 displays a warning using a liquid crystal screen or a lamp. Note that the specific content of the determination process will be described in detail later with reference to other drawings.

The operation input unit 16 is, for example, a plurality of operation buttons, and receives operations on the measuring instrument 1 (for example, starting and ending measurement, raising and lowering values in adjustments during acoustic calibration, etc.) and inputs them to the control unit 13. In response to this, the control unit 13 performs control according to the received operation.

Further, although not shown, the measuring instrument 1 can be connected to an external device such as a PC by wire or wirelessly. Management of measurement data, creation of reports, etc. can be performed via dedicated software installed on such external equipment. If the measuring instrument 1 is connected to an external device during acoustic calibration, evaluation values and warnings can be displayed via dedicated software. When the measuring device 1 is a noise exposure meter, the main body is often designed to be small in consideration of the burden on the wearer, and the display section 15 may not be equipped with a liquid crystal screen. It is possible to display the evaluation value for the reference sound and accept adjustments thereof via dedicated software.

Although the storage section 14 described above is provided inside the measuring instrument 1, it is also possible to use a storage area provided outside the measuring instrument 1 as the storage section. For example, when the measuring instrument 1 is used while connected to an external device, the above-mentioned adjustment values A to C may be stored in a storage area provided inside the external device.

[Determination processing (first form)]
FIG. 2 is a flowchart showing an example of the procedure of the first form of processing executed in conjunction with acoustic calibration of the measuring instrument 1. As shown in FIG. In the example procedure, the acoustic calibration at the beginning is performed manually, but all subsequent processing (judgment processing) is automatically performed by the measuring instrument 1. The procedure will be explained below using an example procedure.

Step S11: Acoustic calibration is performed before and after measurement using the measuring instrument 1, or when checking the operation of the measuring instrument 1. Specifically, first, a specified sound calibrator is attached to the microphone of measuring device 1, a reference sound is generated from the sound calibrator to give a reference sound pressure to the microphone, and the evaluation value calculated by measuring device 1 is Check whether the reference value (for example, 94.0 dB) is reached. If the evaluation value deviates from the reference value, use the operation buttons (for example, up and down keys) of the measuring instrument 1 to adjust the evaluation value to the reference value. At this time, the adjustment value A is changed using the same initial value as the adjustment value B stored in the storage unit 14, and the adjustment value A is determined when the adjustment is completed.

Steps S12 to S14: The control unit 13 acquires the adjustment value A determined by the acoustic calibration performed in step S11 (step S12), acquires the adjustment value B from the storage unit 14 (step S13), and obtains the adjustment value A. It is checked whether the absolute value of the difference between and the adjustment value B is smaller than a predetermined threshold Th1 (step S14). As a result of the confirmation, if the absolute value of the difference is smaller than the threshold Th1 (step S14: Yes), the control unit 13 proceeds to step S16. On the other hand, if the absolute value of the difference is greater than or equal to the threshold Th1 (step S14: No), the control unit 13 proceeds to step S19.

Steps S16 and S17: Next, the control unit 13 acquires the adjustment value C from the storage unit 14 (step S16), and determines whether the absolute value of the difference between the adjustment value A and the adjustment value C is smaller than a predetermined threshold Th2. It is confirmed whether or not (step S17). As a result of the confirmation, if the absolute value of the difference is smaller than the threshold Th2 (step S17: Yes), the control unit 13 proceeds to step S18. On the other hand, if the absolute value of the difference is greater than or equal to the threshold Th2 (step S17: No), the control unit 13 proceeds to step S19.

Step S18: The control unit 13 determines that it is normal.

Steps S19 and S20: The control unit 13 determines that there is an abnormality (step S19), and executes a warning process (step S20). In the warning process, the control unit 13 displays a warning using the LCD screen and lamp of the display unit 15, and also displays a warning on the dedicated software screen if an external device is connected to the measuring instrument 1. conduct.

Step S21: The control unit 13 updates (overwrites) the adjustment value B stored in the storage unit 14 with the adjustment value A.

Note that the above-described procedure is just an example, and can be changed as appropriate depending on the situation. For example, updating of adjustment value B (step S21) may be performed immediately after comparing adjustment value A and adjustment value B (immediately after step S14). Further, the determination based on the comparison between the adjustment value A and the adjustment value B (step S14) may be performed after the determination based on the comparison between the adjustment value A and the adjustment value C (step S17).

In this way, in the first form of the determination process, if the absolute value of the difference between the current adjustment value A and the previous adjustment value B is greater than or equal to the threshold Th1, or if the current adjustment value A and the adjustment at the time of manufacturing If the absolute value of the difference from the value C is greater than or equal to the threshold Th2, there is a possibility that the measuring instrument 1 is malfunctioning, so it is determined that it is abnormal and a warning is issued. Therefore, any user can easily recognize that there is a problem with the measuring instrument 1 and that the measuring instrument 1 should not be used for measurement.

[Determination processing (second form)]
FIG. 3 is a flowchart illustrating an example of a second form of processing executed in conjunction with acoustic calibration of the measuring instrument 1. In the first form of the judgment process described above, the judgment as to whether or not it is normal is made based on the absolute value of the difference between the adjustment values, whereas in the second form of the judgment process, the judgment is made based on the absolute value of the difference between the adjustment values. Judgment is made based on this. Hereinafter, a description will be given along with a procedure example while omitting content common to the first embodiment.

Step S31: Acoustic calibration of the measuring instrument 1 is performed.
Steps S32 to S34: The control unit 13 acquires the adjustment value A determined by the acoustic calibration performed in step S31 (step S32), acquires the adjustment value B from the storage unit 14 (step S33), and obtains the adjustment value A. and the adjustment value B (adjustment value A/adjustment value B) is checked to see if it is greater than or equal to a predetermined threshold Th3 and less than or equal to a predetermined threshold Th4 (step S34). For example, the threshold Th3 is 0.93 (approximately -0.3 dB), and the threshold Th4 is 1.07 (approximately 0.3 dB).

As a result of the confirmation, if the ratio between the adjustment value A and the adjustment value B is greater than or equal to the threshold value Th3 and less than or equal to the threshold value Th4 (step S34: Yes), the control unit 13 proceeds to step S36. On the other hand, if the ratio is smaller than the threshold Th3 or larger than the threshold Th4 (step S34: No), the control unit 13 proceeds to step S39.

Steps S36, S37: Subsequently, the control unit 13 acquires the adjustment value C from the storage unit 14 (step S36), and the ratio of the adjustment value A and the adjustment value C (adjustment value A/adjustment value C) is set to a predetermined value. It is confirmed whether or not the threshold value is greater than or equal to a threshold value Th5 and less than or equal to a predetermined threshold value Th6 (step S37). For example, the threshold Th5 is 0.8 (approximately -1.0 dB), and the threshold Th6 is 1.25 (approximately 1.0 dB).

As a result of the confirmation, if the ratio between the adjustment value A and the adjustment value C is greater than or equal to the threshold Th5 and less than or equal to the threshold Th6 (step S37: Yes), the control unit 13 proceeds to step S38. On the other hand, if the ratio is smaller than the threshold Th5 or larger than the threshold Th6 (step S37: No), the control unit 13 proceeds to step S39.

Step S38: The control unit 13 determines that it is normal.

Steps S39 and S40: The control unit 13 determines that there is an abnormality (step S39), executes a warning process, and displays a warning on the LCD screen of the display unit 15, the lamp, and the screen of the external device connected to the measuring instrument 1. (Step S40).

Step S41: The control unit 13 updates (overwrites) the adjustment value B stored in the storage unit 14 with the adjustment value A.

In this way, in the second form of determination processing, if the ratio between the current adjustment value A and the previous adjustment value B is smaller than the threshold Th3 or larger than the threshold Th4, or if the ratio between the current adjustment value A and the manufacturing If the ratio to the adjustment value C is smaller than the threshold Th5 or larger than the threshold Th6, there is a possibility that the measuring device 1 is out of order, so it is determined that it is abnormal and a warning is issued. Therefore, any user can easily recognize that there is a problem with the measuring instrument 1 and that the measuring instrument 1 should not be used for measurement.

As explained above, the measuring device 1 provides the following effects.

(1) According to the measuring device 1, using three types of adjustment values: the current adjustment value, the previous adjustment value, and the adjustment value at the time of manufacture, whether or not it is normal (Is there any problem with the measuring device 1? Since the system automatically performs the judgment of whether the measuring device 1 is abnormal or not, and issues a warning if it is determined to be abnormal, even users who are inexperienced in measurement can easily recognize that there is a problem with the measuring device 1. Since it is known that measurement should not be performed using the measuring device 1, it is possible to prevent measurement errors that may occur due to measuring using the measuring device 1 that may be out of order.

(2) Abnormalities that gradually deviate from the microphone sensitivity at the time of shipment (manufacturing) are difficult to detect with general acoustic calibration, and are detected during periodic inspections for type approval by calibration organizations, etc. There are many cases. If an abnormality is detected in this way, the reliability of measurements made using the measuring instrument since the previous periodic inspection will be questioned, and the measurement data may become unusable. On the other hand, according to the measuring device 1, it is possible to automatically detect abnormalities such as those mentioned above without overlooking them, and a warning is issued when an abnormality is detected, so even users who are inexperienced in measurement can easily detect the warning when performing sound calibration. By not using the measuring device that issued the warning (using the measuring device that did not issue the warning during acoustic calibration), it is possible to perform the measurement safely.

The present invention is not limited to the above-described embodiments and modifications thereof, and can be implemented in various modifications.

In the embodiment described above, warnings are displayed on the liquid crystal screen and lamps constituting the display unit 15, and on the dedicated software screen of the external device connected to the measuring instrument 1. If the device is equipped with a warning sound, a warning sound may be output from the speaker along with the warning display as described above.

Although two forms of judgment processing are shown in the above-mentioned embodiment, the measuring device 1 may be implemented with either one form of judgment processing, or both forms of judgment processing may be implemented. Alternatively, the configuration may be such that the user can select one of the modes by setting the determination mode of the measuring instrument 1 or the like.

In addition, the configurations, numerical values, etc. mentioned in the course of the explanation regarding the measuring instrument 1 are merely examples, and it goes without saying that modifications can be made as appropriate when implementing the present invention.

1 Measuring instrument 11 Microphone 12 Preamplifier 13 Control section 14 Storage section 15 Display section 16 Operation input section

Claims (4)

A measuring device for performing noise measurement, noise exposure measurement, or other measurement related to sound pressure,
A microphone that inputs sound,
a control unit that controls execution of acoustic calibration based on a signal corresponding to the sound;
As adjustment values for adjusting individual differences in sensitivity of the microphones, a first adjustment value obtained by a predetermined calculation or acoustic calibration at the time of manufacturing the measurement device, and a second adjustment value obtained by the previously performed acoustic calibration. A measuring device comprising: a storage section for storing and; The measuring device according to claim 1,
The control unit includes:
A measurement characterized by performing acoustic calibration to obtain a third adjustment value, and determining whether or not the measuring device is normal based on a comparison between the third adjustment value and the second adjustment value. Device. The measuring device according to claim 2,
The control unit includes:
The measuring device further comprises determining whether or not the measuring device is normal based on a comparison between the third adjustment value and the first adjustment value. The measuring device according to any one of claims 1 to 3,
The storage unit is
A measuring device, characterized in that it is provided inside the measuring device or is connected to the measuring device.

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