Seismic Sensor

Abstract

To provide a novel seismic sensor that can acquire data of the acceleration of an earthquake before detection of the earthquake in a logger function of the seismic sensor and can be operated with reduced power consumption.SOLUTION: A seismic sensor changes an operation mode related to detection of an earthquake or measurement of the acceleration of an earthquake in accordance with measured acceleration, and has a simple earthquake detection mode that is continued when the measured acceleration is equal to or less than a predetermined first threshold and does not store data of the measured acceleration, an earthquake detection mode that is continued when the acceleration measured in the simple earthquake detection mode is larger than the first threshold and equal to or less than a second threshold larger than the first threshold and stores data of the measured acceleration, and an earthquake measurement mode that is continued when the acceleration measured in the earthquake detection mode is larger than the second threshold and measures and stores the acceleration and an SI value.SELECTED DRAWING: Figure 5

Description

[Technical field]

[0001] The present invention relates to a seismic sensor. [Background technology]

[0002] It is especially desirable to reduce standby power consumption in battery-powered devices installed in meter boxes, such as seismic sensors used to cut off gas or electricity when an earthquake occurs. However, while seismic sensors using MCUs (Micro Controller Units) can obtain index values ​​for evaluating the scale of an earthquake through calculation processing, they tend to consume more power than conventional mechanical seismic sensors that are energized by vibration.

[0003] Conventionally, this type of seismic sensor would determine whether an earthquake has occurred after switching from a reduced power consumption mode to a measurement mode, and would then return to the reduced power consumption mode if it determined that there was no earthquake. In this type of seismic sensor, technology has been proposed to improve the accuracy of the determination by filtering the measured acceleration and removing noise components (for example, Patent Document 1).

[0004] In addition, a seismometer has been proposed that can accurately distinguish whether a detected vibration is noise or an earthquake by raising a trigger level according to the calculated noise level, and also sets a threshold value that may delay the detection of an earthquake.If the noise level exceeds this threshold for a certain period of time, an abnormality has occurred that prevents the earthquake from being detected accurately, and an abnormality warning means issues an alarm, accurately indicating that the detection of the earthquake may be delayed (for example, Patent Document 2). [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2017-15604 A [Patent Document 2] JP 2013-108847 A Summary of the Invention [Problem to be solved by the invention]

[0006] In addition to reducing power consumption and increasing the sensitivity of earthquake detection, seismic sensors for measuring earthquakes such as those described above are required to be able to obtain data on the acceleration of vibrations before an earthquake is detected, in order to study the acceleration before and after the occurrence of an earthquake.

[0007] One solution to this problem would be to constantly acquire acceleration data at regular intervals before detecting an earthquake and switching to measurement mode, but in that case, it may be difficult to guarantee that a battery-powered seismic sensor will function for long periods of time, such as five or ten years. Alternatively, there is a risk that users will have to replace batteries more frequently, which can be a hassle.

[0008] In view of the above problems, the ultimate objective of the present invention is to provide a seismic sensor that has a logger function that can acquire vibration acceleration data even before an earthquake is detected, and that can reduce power consumption as much as possible.

[0009] Here, in the present invention, the seismic sensor having the above-mentioned logger function may simply be a seismic sensor. [Means for solving the problem]

[0010] To solve the above problems, the present invention provides: A seismic sensor that switches between operation modes related to detecting earthquakes or measuring the acceleration of earthquakes depending on the measured acceleration, a simple earthquake detection mode that is continued when the measured acceleration is equal to or less than a first predetermined threshold, and in which the measured acceleration data is not stored; an earthquake detection mode that is continued when the acceleration measured in the simple earthquake detection mode is greater than the first threshold and is equal to or less than a second threshold greater than the first threshold, and in which data of the measured acceleration is stored; The earthquake detection mode is continued when the acceleration measured in the earthquake detection mode is greater than the second threshold, and an earthquake measurement mode is provided in which the acceleration and SI (Spectrum Intensity) values ​​are measured and stored. It is a seismic sensor. According to the present invention, even in the simple earthquake detection mode in which the storage process of the earthquake acceleration is not performed, the acceleration is measured, so that it is possible to detect an earthquake with low power consumption. Moreover, when the acceleration measured in the simple earthquake detection mode is equal to or greater than a predetermined first threshold, the mode is switched to the earthquake detection mode, and the acceleration is measured and stored, so that it is possible to record the acceleration data before the occurrence of an earthquake. Moreover, when the acceleration measured in the earthquake detection mode is equal to or greater than a predetermined second threshold, the mode is switched to the earthquake measurement mode, and the SI value is measured and stored in addition to the acceleration, so that when a large acceleration that is judged to be an earthquake occurs, it is possible to record an index of the effect of the earthquake motion on the structure. That is, according to the present invention, it is possible to obtain the acceleration information before the occurrence of an earthquake with low power consumption.

[0011] The present invention may also be a seismic sensor comprising an information processing device and an acceleration sensor, characterized in that in the simple earthquake detection mode, the information processing device is OFF and the acceleration sensor is ON, and in the earthquake detection mode and the earthquake measurement mode, the information processing device is in an intermittent drive state and the acceleration sensor is ON. According to this, in the simple earthquake detection mode, since the information processing device is OFF, it is possible to reduce power consumption more reliably. Also, since the low-power consumption acceleration sensor is ON, it is possible to detect an earthquake from micro-vibrations before the occurrence of an earthquake.

[0012] The present invention may also provide a seismic sensor further comprising a storage unit for storing the acceleration data, the period of the earthquake detection mode and the earthquake measurement mode being divided into predetermined acceleration data acquisition periods, the acceleration data measured by the acceleration sensor at each acceleration data acquisition period being temporarily stored in a memory in the information processing device, and the acceleration data temporarily stored in the memory in the information processing device being stored in the storage unit after the earthquake measurement mode is terminated. This allows the seismic sensor to obtain acceleration data triggered by an earthquake.

[0013] In addition, the present invention may be a seismic sensor characterized in that the acceleration data acquisition period is 20 seconds, and the acceleration data stored in the memory unit after the earthquake measurement mode is terminated is the acceleration data acquired during the entire data acquisition period in the earthquake measurement mode and the acceleration data acquired during the data acquisition period immediately before the occurrence of an earthquake in the earthquake detection mode. This makes it possible to record acceleration data immediately before the occurrence of an earthquake in addition to during the occurrence of an earthquake.

[0014] In addition, the present invention may be a seismic sensor characterized in that after completing the storage of acceleration data acquired during the entire data acquisition period in the earthquake measurement mode, the mode is switched back to the simple earthquake detection mode. This makes it possible to acquire acceleration data at the time of an earthquake occurrence with high reliability, and leads to a reduction in power consumption. In addition, once an earthquake has subsided, it is possible to continue measuring acceleration again with low power consumption. do. Effect of the Invention

[0015] In the seismic sensor, the logger function makes it possible to obtain data on vibration acceleration before an earthquake is detected, and also makes it possible to reduce power consumption in measuring acceleration before an earthquake is detected. [Brief description of the drawings]

[0016] [Figure 1] FIG. 1 is a diagram showing the configuration of a device that is the basis for a seismic sensor. [Diagram 2] FIG. 1 is a diagram for explaining the actual conventional operation of an acceleration logger and a seismic sensor. [Diagram 3] FIG. 13 is a diagram for explaining a case where a seismic sensor is operated in an earthquake detection mode before detecting the occurrence of an earthquake. [Figure 4] FIG. 11 is a process flow diagram relating to the operation mode of the seismic sensor. [Diagram 5] FIG. 2 is a diagram for explaining the operation mode of the seismic sensor. [Figure 6] FIG. 13 is a diagram for explaining the acquisition of acceleration data from a seismic sensor. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0017] [Application example] In this application example, a case will be described in which a logger function for acquiring acceleration data and a simple earthquake detection mode, which is an operation mode for reducing power consumption, are applied to a seismic sensor. As shown in FIG. 1, the seismic sensor according to this application example includes an acceleration sensor 11, an MCU 12 for detecting the occurrence of an earthquake and calculating the magnitude of the earthquake based on the acceleration measured by the acceleration sensor 11, a memory unit 13 for storing the measured acceleration and thresholds used for earthquake judgment, an output unit 14 for outputting information indicating the occurrence and magnitude of an earthquake, and an input unit 15 which is an input terminal of the MCU 12. Then, depending on the magnitude of the measured acceleration, the operation mode for detecting an earthquake and measuring the acceleration of the earthquake is switched. More specifically, as shown in FIG. 5, the operation modes are classified into three types, and the sensor operates in one of a simple earthquake detection mode, an earthquake detection mode, and an earthquake measurement mode.

[0018] In the simple earthquake detection mode, acceleration is measured and the measured acceleration data is not stored. The simple earthquake detection mode operates continuously when the measured acceleration is equal to or less than a predetermined first threshold.

[0019] In the earthquake detection mode, acceleration is measured and the measured acceleration data is stored, and the earthquake detection mode continues to operate when the acceleration is greater than a first threshold and less than or equal to a second threshold, where the second threshold is greater than the first threshold.

[0020] In the earthquake measurement mode, the acceleration and the SI value are measured, and the measured acceleration and the SI value are stored. The earthquake measurement mode operates continuously for a predetermined time when the acceleration measured in the earthquake detection mode is greater than a second threshold value.

[0021] As described above, the seismic sensor 1 includes the MCU 12 and the acceleration sensor 11. In the simple earthquake detection mode, the MCU 12 is ON and the acceleration sensor 11 is OFF, and in the earthquake detection mode and earthquake measurement mode, the MCU 12 and the acceleration sensor 11 are both ON.

[0022] As shown in Fig. 6, the acceleration data is temporarily stored at regular intervals of 20 seconds. The period during which data is stored using an earthquake as a trigger is the 120 seconds during which an earthquake is detected in the earthquake measurement mode, and the 20 seconds before the earthquake occurs in the earthquake detection mode. The earthquake measurement mode is After saving 20 seconds of measurement data, the mode will switch to simple earthquake detection mode.

[0023] Example 1 A seismic sensor according to an embodiment of the present invention will be described below with reference to the drawings. In the following embodiment, an example in which the present invention is applied to a module-type seismic sensor will be described, but the present invention may also be applied to other seismic sensors, such as a board-type seismic sensor. The embodiment shown below is an example of a module-type seismic sensor, and the module-type seismic sensor according to the present invention is not limited to the following configuration.

[0024] <Device configuration> 1 is a diagram showing the configuration of a device that is the basis of the seismic sensor according to this embodiment. The seismic sensor 1 has an acceleration sensor 11, an MCU 12, a storage unit 13, an output unit 14, and an input unit 15.

[0025] The acceleration sensor 11 is, for example, an acceleration sensor using a piezoelectric element or an acceleration sensor that detects electrostatic capacitance between electrodes. The acceleration measured by the acceleration sensor 11 (also called “sampling”) is output to the MCU 12.

[0026] The MCU 12 is, for example, a general-purpose integrated circuit, and acquires the acceleration measured by the acceleration sensor 11 at a predetermined period, detects the occurrence of an earthquake based on the acceleration, and calculates an index value indicating the scale of the earthquake. The MCU 12 also operates in different modes, such as an active mode or a sleep mode, depending on the situation. The sleep mode is an operating mode in which the MCU 12 operates with limited functions, such as stopping execution of instructions while accepting interrupts and stopping the supply of a clock, thereby reducing power consumption compared to the active mode. In the active mode, the MCU 12 performs a process of determining whether the detected vibration is an earthquake or noise, and calculates an index value indicating the scale of the earthquake.

[0027] The storage unit 13 is a temporary storage means such as a RAM (Random Access Memory) or an EPROM (Erasable Programmable Read Only Memory). The storage unit 13 is a non-volatile memory such as a non-volatile memory (eg, a non-volatile memory), and stores, for example, measured acceleration and a threshold value used for earthquake determination. The storage unit 13 may be a memory built into the acceleration sensor 11 or the MCU 12. The output unit 14 is, for example, an output terminal of the MCU 12. When the MCU 12 determines that an earthquake has occurred, the MCU 12 outputs information indicating the occurrence and scale of the earthquake to another device via the output unit 14. This output unit 14 may have a communication function. The input unit 15 is, for example, an input terminal of the MCU 12. The MCU 12 may receive, for example, the operation of a switch (not shown) or input of a command from another device via the input unit 15.

[0028] Note that a gravitational component may be removed by providing a high-pass filter (not shown) between the acceleration sensor 11 and the MCU 12. Also, the MCU 12 may convert the acceleration measured by the acceleration sensor 11 into an absolute value of acceleration based on a predetermined offset.

[0029] FIG. 2 is a diagram for explaining the actual conventional operation of an acceleration logger and a seismic sensor 1. FIG. 2(a) shows an overview of the operation of an acceleration logger. A typical acceleration logger acquires acceleration data using a start signal or the like as a trigger. This start signal can be (1) a signal generated by clicking a start button, (2) a signal output at a specified time based on a timer setting, (3) a signal output when an acceleration signal of a specified level or higher is detected, or (4) a signal generated by a combination of the above. In particular, when (1) a signal generated by clicking a start button or (2) a signal output at a specified time based on a timer setting is used, it is possible to obtain acceleration data. Since the acquisition of acceleration data begins regardless of the occurrence of an earthquake, the amount of data acquired becomes enormous. Next, FIG. 2(b) shows an overview of the operation of the conventional seismic sensor 1. The conventional seismic sensor 1 acquires acceleration data when triggered by the occurrence of an earthquake. In this case, since the MCU 12 does not operate before the occurrence of an earthquake, it is impossible to acquire vibration acceleration data before the earthquake is detected. Furthermore, if the threshold for detecting the occurrence of an earthquake is excessively high, it is not possible to detect the low-acceleration P-waves that arrive before the S-waves when an earthquake occurs, and if the threshold is excessively low, noise such as daily vibrations may be mistaken for an earthquake.

[0030] As an operating mode of the seismic sensor 1, it is possible to operate the seismic sensor 1 in an earthquake detection mode in which acceleration is detected with less power consumption before the acceleration sensor 11 detects the occurrence of an earthquake. FIG. 3 is a diagram for explaining a case in which the seismic sensor 1 is operated in the earthquake detection mode before the occurrence of an earthquake is detected. In FIG. 3, the acceleration sensor 11 is always in an ON state, and the acquired acceleration data is temporarily stored in a RAM (not shown) in the acceleration sensor 11. In the earthquake detection mode, the MCU 12 receives the acceleration data from the acceleration sensor 11. The MCU 12 continues to be in an ON state for 10 msec and an OFF state for 320 msec, and this is repeated. That is, the MCU 12 acquires acceleration data from the RAM in the acceleration sensor 11 at a rate of 10 msec every 330 msec. The acquired acceleration data is stored in the RAM (not shown) of the MCU 12 for 20 seconds, but is erased after 20 seconds, and the accumulation of acceleration data for 20 seconds starts again.

[0031] In the earthquake measurement mode, the MCU 12 is turned on at the same time as in the earthquake detection mode, and receives acceleration data from the RAM of the acceleration sensor 11 and stores it in the RAM of the MCU 12. At the same time, the SI value shown in formula (1) is calculated.

number

[0032] Even in this case, a huge amount of data will be acquired before the occurrence of an earthquake is detected by the acceleration sensor 11, and the operating time of the MCU 12 will be extended, increasing power consumption and making the system inefficient.

[0033] In consideration of the above problems, the seismic sensor 1 in this embodiment is hereinafter assumed to be a seismic sensor that operates in a mode with reduced power consumption before an earthquake is detected and has a logger function that can acquire data on the acceleration of vibration before an earthquake is detected. Here, the seismic sensor with the logger function is also considered to be equivalent to the seismic sensor 1.

[0034] FIG. 4 is a process flow diagram relating to the operation modes of the seismic sensor 1 in this embodiment. This flow functions by the MCU 12 executing a program stored in the memory unit 13 of the seismic sensor 1. The seismic sensor 1 switches between modes relating to earthquake detection and measurement of earthquake acceleration depending on the magnitude of the measured acceleration. The modes are classified into three types, and the sensor can be operated in either a simple earthquake detection mode, an earthquake detection mode, or an earthquake measurement mode. When this flow is executed, first, the seismic sensor 1 operates in the simple earthquake detection mode (FIG. 4: S101). Next, the acceleration sensor 11 acquires acceleration data in the simple earthquake detection mode (S102). In the simple earthquake detection mode, the acceleration data is not saved.

[0035] The acceleration data acquired in the process of S102 is compared with a predetermined first threshold (acceleration threshold) preset in the seismic sensor 1 (S103). If the acceleration acquired in the simple earthquake detection mode is equal to or less than the first threshold (S103: no), the simple earthquake detection mode continues. On the other hand, if the acceleration acquired in the simple earthquake detection mode is greater than the first threshold (S103: yes), the seismic sensor 1 switches to the earthquake detection mode (S104).

[0036] After the seismic sensor 1 switches to the earthquake detection mode, the acceleration data is acquired and stored (S105). The acquired acceleration is compared with a predetermined second threshold (acceleration threshold) preset in the seismic sensor 1 (S106). Here, the second threshold is greater than the first threshold. If the acceleration acquired in the earthquake detection mode is equal to or less than the second threshold (S106: no), the process returns to S103. In S103, the comparison with the first threshold (acceleration threshold) is performed again (S103). If the acceleration acquired immediately before in S105 is equal to or less than the first threshold (S103: no), the process switches to the simple earthquake detection mode. On the other hand, if the acceleration acquired immediately before in S105 is greater than the first threshold (S103: yes), the earthquake detection mode continues (S104). On the other hand, if the acceleration acquired in the earthquake detection mode is greater than the second threshold value (S106: yes), the seismic sensor 1 switches to the earthquake measurement mode (S107). Here, the earthquake measurement mode corresponds to the measurement mode.

[0037] After the seismic sensor 1 switches to the earthquake measurement mode, acceleration data acquisition is performed (S108). The SI value is calculated from the acquired acceleration (S109). In addition, it is determined whether 120 seconds have passed since switching to the earthquake measurement mode (S111). If 120 seconds have not passed (S111: no), the process returns to S108 and is executed from repeatedly acquiring acceleration data. If 120 seconds have passed (S111: yes), 120 seconds of data in the earthquake measurement mode and 20 seconds of data in the earthquake detection mode are saved (S112), and the mode switches back to the simple earthquake detection mode.

[0038] Fig. 5 is a diagram for explaining the operation modes of the seismic sensor 1 in this embodiment. Switching between the simple earthquake detection mode, earthquake detection mode, and earthquake measurement mode is as shown in the process flow diagram of Fig. 4. When the seismic sensor 1 is in operation, the acceleration sensor 11 is always ON in all modes, and the MCU 12 is OFF in the simple earthquake detection mode, but is ON (intermittently ON) in the earthquake detection mode and earthquake measurement mode.

[0039] Therefore, the power consumption of the seismic sensor 1 can be reduced most in the simple earthquake detection mode in which the acceleration sensor 11 is ON and the MCU 12 is OFF. In addition, when switching from the simple earthquake detection mode to the earthquake detection mode, the MCU 12 transitions to the ON state, so the earthquake detection mode can be used as a logger function before an earthquake occurs.

[0040] FIG. 6 is a diagram for explaining the acquisition of acceleration data by the seismic sensor 1 in this embodiment. FIG. 6(a) shows the internal operation of the seismic sensor 1. FIG. 6(b) shows the operation of the seismic sensor 1. As shown in FIG. 6(a), the acceleration measurement data acquired by the acceleration sensor 11 is temporarily stored in RAM (not shown) in the MCU 12 at regular intervals of 20 seconds. Also, as shown in FIG. 6(b), the period in which the measurement data is saved using an earthquake as a trigger is 120 seconds during which an earthquake is detected in earthquake measurement mode and 120 seconds during which an earthquake is detected in earthquake detection mode. This is the 20 seconds before the occurrence of an earthquake in earthquake measurement mode. Therefore, the seismic sensor 1 can record acceleration data before the occurrence of an earthquake in addition to the acceleration data during the occurrence of an earthquake. Note that acceleration data other than the 120 seconds during which an earthquake is detected in earthquake measurement mode and the 20 seconds before the occurrence of an earthquake in earthquake detection mode is reset after the measurement data is saved.

[0041] In the following, the components of the present invention will be described with reference to the reference numerals in the drawings in order to make it possible to compare the components of the present invention with the configurations of the embodiments. <Invention 1> A seismic sensor (1) in which an operation mode for detecting an earthquake or measuring the acceleration of an earthquake is switched according to a measured acceleration, a simple earthquake detection mode that is continued when the measured acceleration is equal to or less than a first predetermined threshold, and in which the measured acceleration data is not stored; an earthquake detection mode that is continued when the acceleration measured in the simple earthquake detection mode is greater than the first threshold and is equal to or less than a second threshold greater than the first threshold, and in which data of the measured acceleration is stored; An earthquake measurement mode is continued when the acceleration measured in the earthquake detection mode is greater than the second threshold, and the acceleration and SI value are measured and stored. Seismic sensor (1). [Explanation of symbols]

[0042] 1: Seismic sensor 11: Acceleration sensor 12:MCU(Micro Controller Unit) 13: Storage section 14: Output section 15: Input section

Claims

1. A seismic sensor that switches between operation modes related to detecting earthquakes or measuring the acceleration of earthquakes depending on the measured acceleration, a simple earthquake detection mode that is continued when the measured acceleration is equal to or less than a first predetermined threshold and in which the measured acceleration data is not stored; an earthquake detection mode that is continued when the acceleration measured in the simple earthquake detection mode is greater than the first threshold and is equal to or less than a second threshold greater than the first threshold, and in which data of the measured acceleration is stored; An earthquake measurement mode is continued when the acceleration measured in the earthquake detection mode is greater than the second threshold value, and the acceleration is measured and stored, and an SI value is calculated and stored; The device is equipped with an information processing device and an acceleration sensor. In the simple earthquake detection mode, the information processing device is in an OFF state and the acceleration sensor is in an ON state, In the earthquake detection mode and the earthquake measurement mode, the information processing device is in an intermittent drive state and the acceleration sensor is in an ON state; The acceleration data is stored in a storage unit. The period of the earthquake detection mode and the earthquake measurement mode is divided into a predetermined acceleration data acquisition period, The acceleration data measured by the acceleration sensor is temporarily stored in a memory in the information processing device every time the acceleration data acquisition period elapses. The acceleration data temporarily stored in the memory of the information processing device is stored in the storage unit after the earthquake measurement mode is terminated. A seismic sensor characterized in that after the earthquake measurement mode is terminated, the acceleration data stored in the memory unit is the acceleration data acquired during the entire data acquisition period in the earthquake measurement mode and the acceleration data acquired during the data acquisition period immediately before the occurrence of an earthquake in the earthquake detection mode.

2. The acceleration data acquired during the entire data acquisition period in the earthquake measurement mode is saved. After the detection is completed, the mode is switched back to the simple earthquake detection mode. The seismic sensor according to claim 1 .

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