JP2000249772A - Vibration detecting device and earthquake detecting system with it - Google Patents

Abstract

PROBLEM TO BE SOLVED: To capture the maximum vibration of a detection signal and to reliably judge the occurrence of an earthquake by holding a judgment signal for a holding period longer than the prescribed judgment time interval, and holding a new signal for the prescribed holding period when a new signal indicating the vibration exceeding it is inputted. SOLUTION: This vibration detecting device is provided with a semiconductor acceleration sensor 16 outputting the detection signal changed in response to vibration and a trigger signal output means, which samples signals, makes a calculation based on a sensor interface and sampling data, and compares the value with the threshold value held in a memory for judgment, therefore a judgment signal can be held for a holding period longer than the prescribed judgment time interval. A mechanical earthquake sensor 19 is provided together with the vibration detecting device having an acceleration sensor 16, an interface and a controller. A judging circuit 20 outputting a cutoff signal 21 when two judgment outputs detect vibration is provided. The maximum vibration of the judgment signal 18 is held for a fixed period and is reliably captured by the judging circuit 20, two judgment outputs are outputted at the same timing, thereby the occurrence of an earthquake can be judged.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vibration detector, such as a semiconductor acceleration sensor, which is installed in a governor chamber or the like in a gas supply system and detects acceleration in three directions, and calculates a vibration discrimination based on the detection signal. The present invention relates to a vibration detection device and an earthquake detection system in which an arithmetic processing circuit for performing processing is built in an explosion-proof case.

[0002]

2. Description of the Related Art FIG. 6 is a block diagram showing an active vibration damping device using a conventional vibration detecting device disclosed in Japanese Patent Application Laid-Open No. 6-186244. In the figure, 61 is a building, 62, 63, 64 are vibration detecting elements arranged at different height positions of the building 61, and 65 is an amplifier for amplifying the acceleration signal output of the vibration detecting elements 62, 63, 64 and the like. A signal amplifier 66 is a control computer, and 67 is a vibration generator installed on the roof of the building 61.

Next, the operation will be described. In response to the vibration of the building 61, each of the vibration detection elements 62, 63, 64 outputs an acceleration signal, and the signal amplifying section 65 amplifies each acceleration signal and outputs it to the control computer 66. This control computer 66
Outputs a control signal to the vibration generator 67 based on an acceleration signal or the like that changes according to the vibration,
(1) Suppress vibrations caused by earthquakes, etc. to prevent collapse.

[0004]

Since the conventional vibration detecting device and the conventional earthquake detecting system are configured as described above, when the vibration changes, the acceleration signal also changes. However, there has been a problem that it is difficult to reliably and reliably determine the vibration due to the occurrence of an earthquake or the like by reliably capturing the acceleration signal corresponding to the maximum vibration of the acceleration signal as the input signal.

In particular, a separate mechanical vibration detecting device is also used so as to prevent erroneous earthquake occurrence determination due to malfunction of a single vibration detecting device, and the final vibration is determined based on these two detected outputs. In such a case, the response characteristics from the occurrence of the earthquake to the change in the detection output differ for each vibration detection device.For example, after the output of the vibration detection device returns A vibration detection output based on the same vibration may be output from the detection device, and there is a problem that it is very difficult to set a determination condition for an earthquake occurrence determination based on these two detection outputs.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-described problems, and has as its object to provide a vibration detecting device capable of reliably detecting the maximum vibration of a detection signal.

The present invention has been made in order to solve the above-mentioned problems, and the setting of the conditions for determining the occurrence of an earthquake is easy, and the maximum vibration of the detection signal is reliably captured to prevent the occurrence of an earthquake. It is an object of the present invention to obtain a stable and reliable earthquake detection system.

[0008]

A vibration detecting device according to the present invention includes a vibration detector that outputs a detection signal that changes according to vibration, a sampling unit that samples the detection signal and outputs sampling data, A predetermined operation is performed based on the sampling data, a vibration determination unit that outputs a determination signal for each predetermined determination time interval, and the determination signal is held for a predetermined holding period longer than the predetermined determination time interval, Further, when a discrimination signal indicating a vibration exceeding that is input during the holding period, an output means for holding the new discrimination signal for the predetermined holding period is provided.

In the vibration detecting device according to the present invention, the vibration discriminating means selects a plurality of natural periods to be used for the calculation at an uneven period interval.

[0010] The earthquake detecting system according to the present invention is configured such that the above-mentioned vibration detecting device, the mechanical vibration detecting device, and the discrimination outputs of these two vibration detecting devices are inputted, and both of these two discriminating outputs are vibration detection. And a final determining means for outputting an earthquake detection signal.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below. Embodiment 1 FIG. FIG. 1 is a block diagram showing a gas supply system to which an earthquake detection system according to Embodiment 1 of the present invention is applied. In the figure, 1 is a gas manufacturing plant having an explosion-proof area, 2 is a gas tank, 3 is a high-pressure pipe, 4 is a governor station having an explosion-proof area, 5 is an emergency shutoff valve, 6 is a medium-pressure pipe, and 7 is an explosion-proof area. Owned governor room, 8 is a low pressure conduit, 9 is a gas-supplied home, 10 is a gas-supplied factory. 11 is a monitoring room, 12 and 13 are emergency shutoff instructions, 14 is a governor having an emergency shutoff function, 1
Reference numeral 5 denotes a governor having an emergency shutoff function.

Reference numeral 16 denotes a semiconductor acceleration sensor (vibration detector) capable of measuring three axes (X, Y, and Z axes) and outputting a detection signal that changes according to vibration, and 17 determines vibration based on the detection signal. An arithmetic processing circuit for outputting a determination signal 18;
Reference numeral 18 denotes a digital (2) output from the arithmetic processing circuit 17.
Value) type determination signal, 19 is a mechanical earthquake sensor (mechanical vibration detection device) that detects vibration using a pendulum or the like,
Reference numeral 20 denotes a judgment circuit (final judgment means) to which a judgment signal 18 and an output signal of the mechanical earthquake sensor 19 are inputted, and when both of them are vibration detections, a cutoff signal (earthquake detection signal) is generated. The cutoff signal 22 is the cutoff signal 21
Governor that shuts off the gas flow path in the explosion-proof area. The semiconductor acceleration sensor 16 and the arithmetic processing circuit 17 are housed in an explosion-proof case because they are installed in the explosion-proof area. It is arranged in the panel 23.

As the semiconductor acceleration sensor 16, for example, a sensor utilizing a change in capacitance described in Japanese Patent Application Laid-Open No. 9-43068 and a signal processing circuit thereof can be used. As described in the section of the prior art of the publication, a plurality of pairs of capacitance elements are provided on opposite surfaces of a fixed substrate and a flexible substrate, and electrodes are attached to each other, and XY parallel to the substrate surface are provided. A plane is set, and changes in acceleration in the three-dimensional directions of the X, Y, and Z axes of the Z axis orthogonal to the plane are determined based on changes in capacitance between a plurality of pairs of capacitance elements. This is to detect a direction component. Then, as outputs with respect to the acceleration in the X-axis direction, the capacitance elements C21 and C2
3 as an output for the acceleration in the Y-axis direction, as a capacitance difference (C22-C24) between the capacitance elements C22 and C24, and as an output for the acceleration in the Z-axis direction. The capacitance C2 of the capacitance element C25
5 or C21 + C22 + C23 + C24. In addition, the semiconductor acceleration sensor 16 is not limited to a capacitance type acceleration sensor, and for example, a piezoresistive or piezoelectric type acceleration sensor can be used. In addition, the semiconductor acceleration sensor 16
It is better to be able to measure axes (X, Y, Z axes). Thereby, accurate vibration measurement of the seismic motion can be performed. In particular, in the case of a direct earthquake, more important measurement information can be obtained because the Z-axis (vertical) direction vibrates first.

FIG. 2 is a block diagram showing a detailed configuration of the arithmetic processing circuit 17 and its peripheral members according to the first embodiment of the present invention. In the figure, reference numeral 45 denotes a sensor interface (sampling means) which receives the detection signal of the semiconductor acceleration sensor 16 and the output of the reference voltage circuit 24 and the correction temperature sensor 25, samples the detection signal and outputs sampling data, and 26 denotes a memory. 27, a real-time clock 28, a backup circuit 29, a power supply circuit 30, and the like, and a control unit (vibration discrimination) that calculates and determines based on the sampling data and outputs a digital (binary) format discrimination signal or an analog signal. Means, output means), and 31 is a digital output interface for outputting this determination signal to the outside. In addition,
In the memory 27, for example, data such as a speed response spectrum and a threshold value for determining the presence or absence of vibration due to an earthquake based on the data are recorded in advance.

In the control unit 26, reference numeral 32 denotes an SI (Spectrum Intensity) value, which is one measure of the intensity of the seismic motion calculated by the SI value calculation unit 32a, the seismic intensity calculated by the seismic intensity calculation unit 32b, and the acceleration calculation unit. 32c, the displacement calculated by the displacement calculator 32d, and the speed calculator 3
Calculation value selection means (vibration determination means) for selecting an arbitrary plurality of calculation values from the respective calculation values of the speed calculated by 2e. That is, the calculated value selecting means 32 can provide an optimum setting at the installation site by appropriately combining various arithmetic functions as needed. A trigger signal output means (output means) 33 performs a vibration determination based on these calculated values, and outputs a determination signal 18. A first signal 34 counts a determination time based on the clock signal of the real-time clock 28. The timer 35 is a second timer that counts the holding time based on the clock signal of the real-time clock 28. Note that these timer functions can be realized by software.

Reference numeral 36 denotes a digital input interface, 37 denotes a relay interface for outputting a result of the arithmetic processing as a relay contact output signal, 38 denotes an analog output interface, and 39 denotes a loader interface. The relay interface 37 is configured to directly connect a circuit such as DC 24 volts or AC 100 volts, so that various loads such as actuators, valves, and large relays can be directly operated. It is something that can be done. The relay interface 37 and a contact-side circuit (not shown) are provided electrically separated from each other. The relay interface 37 is not limited to a structure using a relay, and may be a structure using a separated and insulated electric component such as a photocoupler or a photomos relay. The loader interface 39 includes a loader connection terminal (not shown) for connecting a portable setting device.
A setting signal for causing the calculated value selecting means 32 to select a calculated value is given by means disclosed in Japanese Patent Publication No. 23053, various kinds of information for investigating the cause at the time of failure or abnormality, and Also, it is possible to assist the early start-up of the device by forcibly operating various outputs or monitoring the inputs during the test operation.

The wiring from the external power supply to the power supply circuit 30 and the wiring of each of the interfaces 31, 36, 37, 38, and 39 are drawn out of the explosion-proof case. Also,
Since the discrimination signal 18 is a digital signal, it is resistant to noise, and this wiring is connected from the governor room 7 to the control panel 23.
Even if it is routed to the maximum, it becomes difficult to malfunction.

Next, the operation will be described. FIG. 3 is a flowchart showing the operation of the SI value calculation unit 32a (the other calculation units 32b to 32e have the same operation as the SI value calculation unit 32a) according to the first embodiment of the present invention. In the figure,
ST1 is executed every time the first timer 34 times out (for example, 1
This is a processing step of measuring acceleration / temperature / reference voltage through the sensor interface 45 (every 0 ms). Since the temperature / reference voltage is stable, it is not necessary to perform sampling every cycle equivalent to the sampling cycle of acceleration. For example, measurement is performed every time the timeout of 100 ms comes every 100 times (that is, every second). Is enough.
ST2 calculates a new speed response SV based on these acceleration / temperature / reference voltage, and further calculates a final SI value.
ST3 is an I value calculation step. ST3 holds the newly calculated latest SI value in the holding S value held in the SI value calculation unit 32a.
I value or more (generally, what is actually recorded is memory 2
7 ) Is an update determination step of determining whether or not the current SI value is smaller than the held SI value. ST4 is executed when the second timer 35 times out twice. Is a decision step,
ST5 is a timer reset processing step which is executed when the latest SI value is equal to or greater than the held SI value, and resets the timeout count of the second timer 35, and ST6 is an update processing step for newly holding the latest SI value. .
By the operation of the SI value calculation unit 32a described above, the control unit 26
Is the latest SI every time-out period of the first timer 34
If a value is obtained and an SI value of a higher value is not obtained during the holding period set in the second timer 35, the latest SI value is held at least during the holding period. The trigger signal output means 33 compares the SI value obtained in the above operation with the threshold value set in the memory 27 and outputs the determination signal 18. In the first embodiment, an example of the output of the determination signal based on the SI value has been described.
The same operation is performed when the determination signal is output based on the operation values of the other operation units 32b to 32e.

Next, an operation in the case where an earthquake occurs while the control unit 26 and peripheral components are operating as described above will be described. FIG. 4 is a timing chart illustrating an example of the earthquake detection operation of the earthquake detection system according to the first embodiment of the present invention. In the figure, reference numeral 40 denotes an earthquake vibration waveform, and 41 denotes an S value calculated by the SI value calculation unit 32a based on a detection signal output of the semiconductor acceleration sensor 16 according to the earthquake vibration.
I instantaneous value (calculated SI value), 42 is SI after being held
The output value 43 is a threshold value of the SI value held in the memory 27 to be compared with the SI output value 42. As shown in the figure, the SI output value increases together with the instantaneous value when a vibration due to an earthquake or the like occurs, and the second timer 3 increases even if the instantaneous value decreases.
The maximum instantaneous value is retained until 5 times out twice. Accordingly, the discrimination signal 18 is kept at least for a period until the second timer 35 times out, that is, at least for a period set in the second timer 35.

The judgment circuit 20 outputs the judgment signal 18
When both the vibration and the output of the mechanical seismic sensor 19 are vibration detection, a shutoff signal 21 is generated.
2 shuts off the gas flow path. As a result, the supply of gas to the low-pressure conduit 8 is shut off urgently, and it is possible to effectively prevent an increase in damage due to gas leakage and the occurrence of a secondary disaster.

In the first embodiment, an example has been described in which the determination signal 18 is obtained based only on the SI value. However, according to the installation state of the vibration detection device, for example, both the seismic intensity and the SI value are used. The judgment signal 18 is output. Thereby, more reliable detection can be expected according to the installation state of the vibration detection device.

In the first embodiment, the judgment circuit 2
When 0 is the vibration detection for both the determination signal 18 and the output of the mechanical earthquake sensor 19, the shut-off signal 21 is generated, thereby improving the stability (certainty) of the vibration detection. For example, in a case where it is desired to ensure safety early in the event of an earthquake, when one of the discrimination signal 18 and the output of the mechanical earthquake sensor 19 is a vibration detection, the cutoff signal 21 is generated. Is also good.

Further, since the relay interface 37 outputs the result of the arithmetic processing as a relay contact output signal instead of a digital signal, if this is connected to a circuit of, for example, 24 VDC or 100 VAC, the actuator, valve, Various loads such as large relays can be directly operated. In this case, since the relay interface 37 and the contact side circuit (not shown) are provided electrically separated from each other, the noise characteristics are further improved as compared with the determination signal 18 output from the digital output interface 31.

As described above, according to the first embodiment, the semiconductor acceleration sensor 16 that outputs a detection signal that changes in accordance with vibration, the sensor interface 45 that samples the detection signal, and transmits the sampled data to the sensor interface 45. Calculation value selecting means 32 for calculating various calculation values based on
And a trigger signal output means 33 for comparing the calculated value with a threshold value held in the memory 27, so that the discrimination signal 18 output at each predetermined discrimination time interval is set to be shorter than the predetermined discrimination time interval. It can be held for a long predetermined holding period. In addition, when a vibration exceeding the holding calculated value occurs during the holding period and a new large calculated value is input, the calculated value selecting unit 32 can hold the new large calculated value at least for the predetermined holding period. it can. Therefore, the determination signal 18 determined based on the maximum operation value can be generated and held for a predetermined holding period, and the vibration of the desired maximum operation value can be reliably captured.

According to the first embodiment, the mechanical seismic sensor 19 is provided together with the vibration detecting device having the semiconductor acceleration sensor 16, the sensor interface 45 and the control unit 26, and the discrimination output of these two vibration detecting devices is provided. Is input, and the determination circuit 20 that outputs the cutoff signal 21 when both of these two determination outputs are vibration detection is provided. Therefore, the maximum vibration of the determination signal 18 from the vibration detection device is held for a certain period of time. This can be reliably detected by the determination circuit 20, and the two determination outputs can output detection outputs based on the same vibration at the same timing. It is sufficient to judge that the output is an output. There is an effect that can be determined to.

Further, since the shutoff signal is output based on a plurality of detection signals of the detection devices of different detection systems, the gas supply is inadvertently stopped due to an erroneous earthquake detection of one of the vibration detection devices. There is an effect that enormous expenditure required for the recovery can be prevented.

In the first embodiment, the SI value is held and the vibration is detected based on the SI value. In addition, the acceleration value, the seismic intensity, the displacement, the speed, etc. are also held. Vibration detection may be performed.

Embodiment 2 FIG. 5 is an explanatory diagram for explaining the content of an SI value calculation process according to the second embodiment of the present invention. In the figure, the horizontal axis represents the natural period T, which is the vibration component of the earthquake.
[S], and the vertical axis is the speed response Sv (θ, T). In addition,
Is the projection direction, which is the angle between the speed response vector at the current time and the direction vector for obtaining the SI value. Then, as shown in FIG.
"0.1, 0.6, 1.1, 1.5, 1.9, 2.2,
2.5 "of seven natural periods Tn (n = 1, 2,...,
The velocity response Sv (θ, T) in 7) was substituted into the following equation 1 to determine the SI value of each individual cycle. Then, S, which is the sum of the seven individual period SI values obtained for each projection direction,
The maximum value of the I value was taken as the latest SI value.

[0029]

(Equation 1) Other configurations and operations are the same as those in the first embodiment, and a description thereof will be omitted.

As described above, according to the second embodiment, the arithmetic unit performs the operations of “0.1, 0.6, 1.1, 1.5,
Since a plurality of natural periods used for the SI value calculation are selected at unequal period intervals as in “1.9, 2.2, 2.5”, a period that contributes a large amount to the SI value is set high. Density can be selected, and when it is selected at every even period interval (for example, “0.1, 0.5, 0.9, 1.3,
1.7, 2.1, 2.5 ”), while having the same calculation amount and storage amount, but a higher accuracy SI value (calculation result)
There is an effect that can be obtained.

In particular, in the second embodiment, since the longer natural period is selected so as to have a higher density than the shorter natural period, the natural period having a higher contribution rate to the SI value in the vibration of the earthquake is set to a higher density. , And the SI value based on the vibration of the earthquake can be calculated with high accuracy that is allowable in detecting the earthquake.

From another point of view, the calculation unit selects a plurality of natural periods used for SI value calculation at unequal period intervals, thereby reducing the number of natural periods as compared with a case where the natural period is uniformly obtained. Since an SI value with the same accuracy can be obtained with the number of cycles, the calculation can be speeded up, cost can be reduced,
There are advantages such as easy commercialization.

[0033]

As described above, according to the present invention, a vibration detector that outputs a detection signal that changes according to vibration, a sampling unit that samples the detection signal and outputs sampling data, Vibration determining means for performing a predetermined calculation based on the data and outputting a determination signal for each predetermined determination time interval; and output means for holding the determination signal for a predetermined holding period longer than the predetermined determination time interval. Therefore, it is possible to hold the discrimination signal output every predetermined discrimination time interval for a predetermined holding period longer than the predetermined discrimination time interval. Moreover, when a vibration exceeding the holding calculated value occurs during the holding period and a new large calculated value is input, the output unit can hold the new large calculated value at least for the predetermined holding period. Therefore, it is possible to generate a discrimination signal determined based on the maximum operation value and hold it for a predetermined holding period, so that the vibration of the desired maximum operation value can be reliably captured.

According to the present invention, since the vibration discriminating means selects a plurality of natural periods to be used for calculation at unequal period intervals, the vibration discrimination processing time can be maintained while maintaining the accuracy of the calculation result with high accuracy. Therefore, there is an effect that the number of storage units for storing sampling data can be reduced.

According to the present invention, the above-described vibration detecting device includes:
A mechanical vibration detection device, and a final determination unit that receives a discrimination output of these two vibration detection devices and outputs an earthquake detection signal when both of the two discrimination outputs are vibration detections. The maximum vibration of the detection signal from the detection device can be held for a certain period of time and reliably detected by the final determination means. Further, these two determination outputs can output detection outputs based on the same vibration at the same timing. Since the final determination means can determine that both of the detection outputs are present at the relevant timing, there is an effect that the occurrence of an earthquake can be determined stably and reliably by setting a very simple determination condition. .

[Brief description of the drawings]

FIG. 1 is a block diagram showing a gas supply system to which an earthquake detection system according to a first embodiment of the present invention is applied.

FIG. 2 is a block diagram showing a detailed configuration of an arithmetic processing circuit and its peripheral members according to the first embodiment of the present invention;

FIG. 3 is a flowchart showing an operation of a control unit according to the first embodiment of the present invention.

FIG. 4 is a timing chart illustrating an example of an earthquake detection operation of the earthquake detection system according to the first embodiment of the present invention.

FIG. 5 is an explanatory diagram illustrating contents of an SI value calculation process according to a second embodiment of the present invention;

FIG. 6 is a block diagram showing an active vibration damping device using a conventional vibration detecting device.

[Explanation of symbols]

 Reference Signs List 16 semiconductor acceleration sensor (vibration detector) 19 mechanical earthquake sensor (mechanical vibration detector) 20 determination circuit (final determination means) 26 control unit (vibration determination means, output means) 32 calculation value selection means (vibration determination means) 33 trigger signal output means (output means) 45 sensor interface (sampling means)

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Hiroyuki Furukawa 2-12-19 Shibuya, Shibuya-ku, Tokyo Stock Company Takeuchi Shayama (72) Inventor Hikaru Takubo 2-12-19 Shibuya, Shibuya-ku, Tokyo Stock Company Takeuchi Shayama (72) Inventor Yoshihisa Shimizu 2-26-3 Kahinata, Satte-shi, Saitama (72) Inventor Kenichi Koganemaru 704 Shibaura, Minato-ku, Tokyo 704

Claims (3)

[Claims] 1. A vibration detector that outputs a detection signal that changes in accordance with vibration, a sampling unit that samples the detection signal and outputs sampling data, and performs a predetermined operation based on the sampling data. A vibration discriminating means for outputting a discrimination signal for each predetermined discrimination time interval, a discrimination indicating that the discrimination signal is held for a predetermined holding period longer than the predetermined discrimination time interval, and a vibration exceeding the holding period is displayed. An output unit that, when a signal is input, holds the new determination signal for the predetermined holding period. 2. The vibration detecting device according to claim 1, wherein the vibration determining means selects a plurality of natural periods used for the calculation at unequal period intervals. 3. A vibration detection device according to claim 1 or 2, a mechanical vibration detection device, and a discrimination output of these two vibration detection devices is input, and both of the two discrimination outputs detect vibration. And a final discriminating means for outputting an earthquake detection signal.