JP3345319B2 - Earthquake detection device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a seismic detector installed in a governor room or the like in a gas supply system and capable of confirming the operation of a relay.

[0002]

2. Description of the Related Art When an earthquake occurs in a gas supply system, it is necessary to urgently shut off the gas supply to prevent the damage caused by gas leakage from spreading and the occurrence of secondary disasters. There is provided an earthquake detection device using the same. FIG. 9 is a block diagram showing a gas supply system using a conventional earthquake detection device. In FIG. 9, 101 is a gas manufacturing plant, 102 is a gas tank,
103 is a high pressure conduit, 104 is a governor, 105 is a governor station, 106 is a medium pressure conduit, 107 is a governor, 10
7a is an emergency shutoff valve, 108 is a monitoring room, 109 and 11
Numeral 0 denotes an emergency shutoff instruction, 111 denotes a governor room in which the room is an explosion-proof area, and 112 denotes a governor.

Reference numeral 130 denotes a servo type acceleration sensor which is a force balance type sensor using an electric spring of a servo mechanism. Here, in order to detect acceleration in two axes (X and Y axes), 1
Two axis type servo type acceleration elements are housed in an explosion-proof container. 132 is an analog signal output from the servo type acceleration sensor 130, 140 is an analog signal 132
Is an arithmetic processing circuit that calculates an SI value, which will be described later, and outputs an emergency cutoff signal, based on the above, and is provided outside the governor chamber 111. The set value (threshold value) for determining whether or not to output the emergency cutoff signal is written in advance in the memory or the like of the arithmetic processing circuit 140. It is configured so that settings can be changed.

[0004] Reference numeral 160 denotes a control panel provided on the governor room outer wall surface (non-explosion-proof area), and 161 denotes a mechanical earthquake sensor installed in the control panel 160 and using a pendulum or the like. A determination circuit 162 generates a shutoff signal 163 for shutting off the governor 112 by the relay 162a when both the output signal of the arithmetic processing circuit 140 and the output signal of the mechanical earthquake sensor 161 are output. In addition,
The relay 162a is operably formed by a drive circuit (not shown). 164 is a low pressure conduit, 165 is a gas-supplied home, and 166 is a gas-supplied factory.

In order to detect an earthquake having a high correlation with the degree of damage to a building in such an earthquake detection apparatus, there has been proposed means for using an SI (Spectrum Intensity) value as a measure of the intensity of earthquake motion.
It has been implemented. This SI value is generally expressed by the following equation.

[0006]

(Equation 1) Here, k is a coefficient, Sv is a speed response spectrum, T is a cycle, and h is a damping coefficient of a building.

Such means is disclosed in, for example, JP-A-62-12
Nos. 884, 62-12885, 62-12886, 6-214040, and 8-36062. In such means, the SI value is obtained by inputting the acceleration waveform of the seismic motion measured by the seismic sensor to an arithmetic unit that satisfies the equation of motion of the one-degree-of-freedom vibration system, and obtaining the speed response every moment, and obtaining the maximum value of the speed response. Spectrum, ie,
It is obtained by performing a predetermined calculation from the velocity response spectrum.

Next, the operation will be described. In FIG. 9, when the servo type acceleration sensor 130 detects an earthquake,
The detection signal is input as an analog signal 132 to the arithmetic processing circuit 140 in the non-explosion-proof area. The arithmetic processing circuit 140 calculates the SI value, determines whether or not to output an emergency shutoff instruction based on the calculated value. When the emergency shutoff instruction is output, the instruction is input to the determination circuit 162.

On the other hand, the output of the mechanical earthquake sensor 161 is also input to the judgment circuit 162. Then, the judgment circuit 162 generates a cutoff signal 163 when both the output signal of the arithmetic processing circuit 140 and the output signal of the mechanical earthquake sensor 161 are output, and the governor 112 is cut off by the relay 162a. That is, the supply of gas to the low-pressure conduit 164 is shut off urgently, thereby preventing the damage caused by gas leakage from spreading and the occurrence of secondary disaster.

[0010]

Since the conventional earthquake detecting apparatus is configured as described above, a failure of the relay 162a used for opening / closing the governor 112, a poor soldering of a relay drive circuit, etc., a printed circuit board, and the like. However, even when the relay 162a does not operate due to a pattern break in the above, there is no means for confirming this, and there is a problem such as low reliability.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and has as its object to obtain a highly reliable earthquake detection device capable of reliably confirming the operation of a relay.

Another object of the present invention is to obtain a highly reliable and small-sized earthquake detecting device which can reliably confirm the operation of the relay.

[0013]

An earthquake detecting apparatus according to the present invention includes an acceleration sensor, an arithmetic processing circuit, a feedback circuit, a determining unit, and an alarm unit.

[0014] In the earthquake detecting device according to the present invention, the feedback circuit includes a photocoupler.

[0015]

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 using an earthquake detection device according to Embodiment 1 of the present invention, FIG. 2 is a perspective view showing the earthquake detection device, and FIG.
-A sectional view, FIG. 4 is a plan view showing a state where a cover of the earthquake detection device is removed, FIG. 5 is a circuit configuration diagram of the earthquake detection device,
FIG. 6 is a circuit configuration diagram of the relay interface.

First, a schematic configuration of a gas supply system using the present invention will be described. In FIG. 1, 1 is a gas production plant having an explosion-proof area, 2 is a gas tank, 3 is a high-pressure conduit,
Is the governor, 5 is the governor station with explosion-proof area, 6
Is an intermediate pressure conduit, 7 is a governor, 7a is an emergency shutoff valve, 8 is a monitoring room, 9 and 10 are emergency shutoff instructions, 11 is a governor room as an explosion-proof area, and 12 is a governor having an emergency shutoff function.

Reference numeral 20 denotes an explosion-proof case described later; 30 denotes a semiconductor acceleration sensor capable of measuring three axes (X, Y and Z axes); 40 denotes an arithmetic processing circuit; and 57 denotes an output from the arithmetic processing circuit 40 A relay signal 60 is a control panel provided on the governor room outer wall surface (non-explosion-proof area).

Reference numeral 61 denotes a mechanical seismic sensor which is installed in a control panel 60 and uses a pendulum or the like. 62 denotes a governor when both a relay signal 57 and an output signal of the mechanical seismic sensor 61 are output. A determination circuit for generating a shut-off signal 63 for shutting off 12, a warning indicator 62a, a low-pressure conduit 64, a home supplied with gas 65, and a factory 66 supplied with gas. 70 is a relay described later, 78 is a feedback determination unit described later, 79 is an alarm unit described later, 80
Is an alarm signal described later.

Next, the earthquake detector will be described in more detail. 2 to 4, reference numeral 20 denotes an O-ring 21.
This is an explosion-proof case that has a cover 20a that can be opened and closed via a cable and an electric wire lead-out hole 20b, and is made of metal such as aluminum so as to satisfy a predetermined withstand pressure. This explosion-proof case 20 is manufactured so as to satisfy the standard for explosion-proof electrical equipment (Ministry of Labor). In other words, the length and the number of threads of the screw portion between the explosion-proof case 20 and the cover 20a, the pressure-resistant packing (described later) in the wire lead-out hole 20b, and the like satisfy the above-mentioned standards. Numeral 24 denotes a shielded wire in which various wirings to be described later are put together, 25 denotes a pressure-resistant packing made of, for example, butyl rubber, 26 denotes a compression bolt for compressing the pressure-resistant packing 25, and 27 denotes a lock nut for fixing the compression bolt 26. That is, the shield wire 2 is
4 is inserted, and is provided with a pressure-resistant packing 25, a compression bolt 26, and a lock nut 27, so that the hermeticity and pressure resistance of the relevant portion can be ensured.
The length of the pressure-resistant packing 25 after compression satisfies the above-mentioned standard.

Reference numeral 30 denotes a semiconductor acceleration sensor (acceleration sensor). For example, a sensor using a change in capacitance and a signal processing circuit thereof described in Japanese Patent Application Laid-Open No. 9-43068 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 X, Y, and Z axes of the Z axis orthogonal to the plane are
Each X, based on the capacitance change between a plurality of pairs of capacitance elements
The detection of the Y and Z axis direction components is performed. And X
As an output for the acceleration in the axial direction, the capacitance element C2
As the output with respect to the capacitance difference between C1 and C23 (C21-C23) and the acceleration in the Y-axis direction, the capacitance difference between the capacitance elements C22 and C24 (C22-C24), and the output with respect to the acceleration in the Z-axis direction Can be detected as the capacitance C25 of the capacitance element C25 or C21 + C22 + C23 + C24. Note that the semiconductor acceleration sensor 30 is not limited to a capacitance type acceleration sensor,
For example, a piezoresistive or piezoelectric acceleration sensor can be used.

Reference numeral 31 denotes a support member, and 32 denotes a CPU.
A board, 33 is a power board, 34 is a terminal block, 35 is a guard, and 36 is a loader connection terminal for connecting a portable setting device (not shown) to a loader interface 55 described later.

Next, the circuit configuration of the earthquake detecting device is shown in FIG.
It will be described based on. In FIG. 5, reference numeral 40 denotes the aforementioned C
An arithmetic processing circuit 41 formed by the PU board 32 or the like;
Is a control unit, 42 is the SI value calculated by the SI value calculation unit 42a, the seismic intensity calculated by the seismic intensity calculation unit 42b, the acceleration calculated by the acceleration calculation unit 42c,
This is a calculation value selecting unit that selects any plural calculation values from the respective calculation values of the displacement amount calculated by the displacement amount calculation unit 42d and the speed calculated by the speed calculation unit 42e. That is, the calculated value selecting means 42 is to provide an optimum setting at the installation site by appropriately combining various arithmetic functions as needed.

43 is a calculated value determining means for determining whether or not to output an emergency shutoff instruction or the like based on the calculated value.
Is a memory in which, for example, a threshold value for determination required by the calculated value determination means 43 is recorded in advance. The shutoff instruction is output to the outside via the relay interface 53 as described later. 45 is a real-time clock, 46 is a sensor interface, 47 is a correction temperature sensor, 48 is a reference voltage, 49 is a power supply circuit, and 50 is a backup circuit. 51 is an alarm output interface, 5
2 is a digital input interface, 53 is a relay interface described later, and 54 is an analog output interface. Reference numeral 55 denotes a loader interface for connecting a portable setting device (not shown) that supplies a setting signal for causing the calculated value selecting means 42 to select a calculated value, and includes the loader connection terminal 36 described above. Setting means using such a portable setting device includes, for example, Japanese Patent No.
Means disclosed in 23053 can be used.

The wiring from the external power supply to the power supply circuit 49 and the wiring of each of the interfaces 51, 52, 53, 54 are led out of the explosion-proof case 20 by the above-mentioned shielded wire 24.

Next, the circuit configuration of the relay interface 53 will be described in more detail. 6, reference numeral 70 denotes a relay having an exciting coil 70a, two contacts 70b and 70c, and an interlocking contact 70d; 71, a relay drive circuit for driving the relay 70; 71a, which is output from the control unit 41 to the relay drive circuit 71; Relay drive signal, 72, 73, 7
Reference numeral 4 denotes a terminal, 75 denotes a DC or AC power supply, and 76 denotes various loads such as a governor 12, an actuator, a large relay or an electric circuit. Reference numeral 77 denotes a feedback signal for confirming the operation of the relay 70. For example, when a 71a relay drive signal is output, a high level signal is output when the operation is normal, and a low level signal is output when the operation is abnormal. It is output as a signal. R1, R
2 is a resistor (feedback circuit).

Reference numeral 78 denotes a feedback determination unit for determining whether or not the operation of the relay 70 is normal based on the output state of the relay drive signal 71a and the output state of the feedback signal 77. That is, the feedback determination unit 78 is formed to make the following determination. (1) The relay drive signal 71a is output and the relay 7
If 0 operates, it is determined to be normal. (2) If the relay drive signal 71a is not output and the relay 70 does not operate, it is determined that the relay is normal. (3) The relay drive signal 71a is output and the relay 7
If 0 does not operate, it is determined to be abnormal. (4) If the relay drive signal 71a is not output and the relay 70 operates, it is determined that an abnormality has occurred.

Reference numeral 79 denotes an alarm unit for outputting a drive output to the alarm output interface 51 and outputting an alarm signal 80 when the feedback judgment unit 78 judges that there is an abnormality. The alarm unit 79 is provided by the feedback judgment unit 7.
A configuration may be adopted in which an alarm signal 80 is output when it is determined that 8 is normal.

Next, the operation will be described. 5 and 1
, When the semiconductor acceleration sensor 30 detects an earthquake, a detection signal is input to the control unit 41 via the sensor interface 46. In this case, since the semiconductor acceleration sensor 30 can measure three axes (X, Y, and Z axes), it is possible to more accurately measure the vibration of earthquake motion. In particular, in the case of a direct earthquake, more important measurement information can be obtained because the Z-axis (vertical) direction vibrates first.

In the control unit 41, the SI value, seismic intensity, etc., which are selected in advance by the calculation value selection means 42,
It is calculated by 2a to 42e. The setting signal for causing the calculated value selecting means 42 to select a calculated value is determined by an operator by connecting a portable setting device (not shown) to the loader connection terminal 36 at the installation site and performing loader communication, thereby setting an optimum threshold value for the installation site. Can be set easily and quickly. The determining means 43 determines whether or not to output the emergency shutoff instruction based on the calculated value. When outputting the emergency shutoff instruction, for example, the relay interface 53 sends the relay control signal to the determination circuit 62 of the control panel 60 to the determination circuit 62. Output as signal 57. Therefore, the shielded wire 24 is connected to the governor chamber 1
Even if it is routed from 1 to the control panel 60, it becomes strong against noise,
No malfunction occurs. In this case, more reliable detection can be expected, for example, by outputting a shutoff instruction signal when both the SI value and the seismic intensity exceed a predetermined value.

Then, the relay signal 57 is input to the determination circuit 62 of the control panel 60 as shown in FIG. On the other hand, the output of the mechanical earthquake sensor 61 is also input to the determination circuit 62. When both the relay signal 57 and the output signal of the mechanical earthquake sensor 61 are output, the determination circuit 62 determines as a logical product and generates a cutoff signal 63, and the governor drive circuit (not shown) controls the governor drive circuit. 12 is shut off. As will be described later in detail, when the feedback determination section 78 determines that the relay 70 is not operating normally and the alarm section 80 outputs an alarm signal 80, the alarm display 62a outputs the signal through the determination circuit 62. A predetermined alarm is displayed.

As described above, the supply of gas to the low-pressure conduit 64 is shut off urgently, so that it is possible to effectively prevent the damage caused by gas leakage and the occurrence of secondary disaster, and to reliably confirm the operation of the relay 70. Overall reliability can be improved. When it is desired to output the cutoff signal 63 early in the determination circuit 62 to ensure safety during an earthquake, the determination signal may be determined as the logical sum of the relay signal 57 and the output signal of the mechanical earthquake sensor 61. it can.

Next, the operation of the relay interface 53 and the like will be described with reference to FIG. When the SI value or the like exceeds a predetermined threshold, the control unit 41 outputs a relay drive signal 71a. Then, the relay drive circuit 71
The excitation coil 70a is excited by the
And the contacts 70b and 70c are closed, and the load 76 can be directly driven. When the relay 70 operates, a high-level feedback signal 77 is output to the feedback determination unit 78. When the relay 70 does not operate, the low-level feedback signal 77 is output to the feedback determination unit 78 without any change. Will remain.

The feedback determination section 78 determines whether or not the operation of the relay 70 is normal based on the output state of the relay drive signal 71a and the output state of the feedback signal 77 as follows. That is, (1) the relay drive signal 71a is output and the relay 7
If 0 operates, it is determined to be normal. (2) If the relay drive signal 71a is not output and the relay 70 does not operate, it is determined that the relay is normal. (3) The relay drive signal 71a is output and the relay 7
If 0 does not operate, it is determined to be abnormal. (4) If the relay drive signal 71a is not output and the relay 70 operates, it is determined that an abnormality has occurred.

When the feedback judgment section 78 judges that the alarm is abnormal, the alarm section 79 outputs the alarm output interface 51.
And outputs an alarm signal 80 via the. Therefore, a failure of the relay 70, a defective soldering of the relay drive circuit 71, etc.,
Even when the relay 70 does not operate due to a cut-out of a pattern on the printed circuit board or the like, this can be confirmed, so that the reliability of the entire system can be improved.

As described above, according to the first embodiment, the operation of the relay 70 can be surely confirmed, and the effect of providing a highly reliable earthquake detecting device can be obtained. In particular, since the feedback circuit that outputs the feedback signal 77 is independent of the output contact 70c, a very simple circuit configuration can be obtained, and the effect of improving reliability can be obtained.

Further, by using the small-sized semiconductor acceleration sensor 30, the arithmetic processing circuit 40 can also be built in the explosion-proof case 20, so that the whole device can be reduced in size and weight, and the effect of easy handling can be obtained.

Further, since the emergency cutoff instruction from the arithmetic processing circuit 40 is output as the relay signal 57, the reliability against noise is remarkably improved, and an effect that the malfunction of the device can be effectively prevented can be obtained.

Further, since the semiconductor acceleration sensor 30 can measure three axes (X, Y, and Z axes), it is possible to measure vibration of earthquake motion more accurately. In particular, a direct type earthquake in which the Z axis (vertical) direction vibrates first. Thus, an effect that more important measurement information can be obtained is obtained.

Further, in addition to the SI value required by the gas industry, the seismic intensity required by the Meteorological Agency, and the displacement and speed required by the construction industry can be arbitrarily calculated by the calculated value selecting means 42, If you need to increase or change product delivery destinations, thresholds, measured quantities, etc.,
The effect that can respond easily and flexibly is obtained.

Further, for example, when an alarm signal is output when both the SI value and the seismic intensity exceed a predetermined value, an effect that a more reliable detection can be expected can be obtained.

A setting signal for causing the calculation value selection means 42 to select a calculation value is transmitted to the loader connection terminal 36 by an operator at the installation site by connecting a portable setting device (not shown) to the loader connection terminal 36 so as to communicate with the loader. The effect of easily and quickly setting the optimum threshold value for the ground and the building is obtained.

In the first embodiment, the pull-up resistor R1 is pulled up to Vcc by the contact 70b to form a feedback circuit. However, the present invention is not limited to this. It may be constituted by a circuit. When the relay 70 operates, a high-level feedback signal 77 is output to the feedback determination unit 78. When the relay 70 does not operate, a low-level feedback signal 77 is output to the feedback determination unit 78. As explained above,
The present invention is not limited to this, and the level of the feedback signal 77 may be reversed. In the illustrated example, the circuit of the load 76 is intermittently controlled by the relay 70, but other circuits may be intermittently controlled by the relay 70. Also in this case, the operation state of the relay 70 is reliably determined by the feedback determination unit 78 to which the feedback signal 77 is input.

Embodiment 2 FIG. 7 is a circuit configuration diagram of a relay interface according to Embodiment 2 of the present invention.
Hereinafter, the same or corresponding members as those already described are denoted by the same reference numerals, and description thereof will be omitted. FIG.
, 81 is a diode (feedback circuit),
82 is a Zener diode (feedback circuit), 8
Reference numeral 3 denotes a photocoupler (feedback circuit), and reference numeral 84 denotes a capacitor (feedback circuit). The photocoupler 83 has a clear load 76 on the contact 70b, and can be used, for example, in the case of a low-voltage electric load. With a low-voltage electric load, the photocoupler 83 can be directly connected. R3, R4, R5, R
Reference numeral 6 denotes a resistor (feedback circuit). The relay 70 uses a contact relay of one circuit, and uses a diode 8
1 and the capacitor 84 are used when the power supply 75 is an AC power supply.

Next, the operation will be described. When the SI value or the like exceeds a predetermined threshold, the control unit 41 outputs a relay drive signal 71a. Then, the excitation coil 70a is excited by the relay drive circuit 71, and the contact 70
b is closed and the load 76 can be driven directly.
Then, the photocoupler 83 is turned on, and a low-level feedback signal 77 is output to the feedback determination unit 78. On the other hand, when the relay 70 does not operate, the high-level feedback signal 77 is output to the feedback determination unit 78 without any change.

The feedback determining section 78 determines whether or not the operation of the relay 70 is normal from the output state of the relay drive signal 71a and the output state of the feedback signal 77 in the same manner as in the first embodiment. If it is determined, the alarm unit 79 outputs an alarm signal 80 via the alarm output interface 51. Therefore, even when the relay 70 does not operate due to a failure of the relay 70, a poor soldering of the relay drive circuit 71 or the like, or a broken pattern on a printed circuit board, it is possible to confirm the fact that the relay 70 does not operate, thereby improving the reliability of the entire system. Can be.

As described above, according to the second embodiment, the same effect as that of the first embodiment using the two-circuit contact relay 70 can be obtained.
By using the photo coupler 83 and the photo coupler 83, the effect of further reducing the size of the device can be obtained.

Embodiment 3 The present embodiment 3 is an earthquake detecting device using a servo type acceleration sensor, means for confirming whether or not the operation of a relay is normal, and outputting an abnormal signal for outputting an abnormal signal when the operation is confirmed to be abnormal. And means.

FIG. 8 is a block diagram showing a gas supply system using an earthquake detecting apparatus according to Embodiment 3 of the present invention. In FIG. 8, reference numeral 86 denotes a servo which is a force-balancing sensor using an electric spring of a servo mechanism. Type acceleration sensor (acceleration sensor). Here, two uniaxial servo type acceleration elements are housed in an explosion-proof container in order to detect biaxial (X, Y axis) acceleration. Reference numeral 87 denotes an analog signal output from the servo acceleration sensor 86, and 88 denotes an arithmetic processing circuit that calculates an SI value based on the analog signal 87 and outputs an emergency cutoff signal, and is provided outside the governor chamber 11. . The set value (threshold value) for determining whether to output the emergency cutoff signal is determined by the arithmetic processing circuit 8.
8 is stored in advance in a memory or the like, but is configured so that the setting can be changed later on site by using a dip switch or the like as necessary.

Reference numeral 62 denotes a drive signal for driving a relay 70 when both the output signal of the arithmetic processing circuit 88 and the output signal of the mechanical earthquake sensor 61 are output, and the governor 12 is cut off by the relay 70. Shut-off signal 6
A judgment circuit 89 for generating 3 is an operation processing unit (operation processing circuit) including the judgment circuit 62 and the operation processing circuit 88.

The relay 70, the feedback judgment unit 78,
The alarm unit 79 is formed similarly to the configuration of FIG. 6 shown in the first embodiment or FIG. 7 shown in the second embodiment.

Next, the operation will be described. The relay 70 is driven by the drive signal of the determination circuit 62, and the first embodiment is used.
Alternatively, a predetermined feedback signal is output to feedback determining section 78 by a feedback circuit (not shown) as in the second embodiment. When the feedback determination unit 78 determines that the operation of the relay 70 is abnormal, the alarm unit 79
Outputs an alarm signal, and issues a predetermined alarm by the alarm display 62a.

As described above, according to the third embodiment, even in an earthquake detecting apparatus using the servo type acceleration sensor 86, the operation of the relay 70 can be surely confirmed, and the reliability can be improved. The effect that can be obtained is obtained.

[0053]

As described above, according to the present invention, the acceleration sensor, the arithmetic processing circuit, the feedback circuit,
Since it is configured to include the feedback determination unit and the alarm unit, the operation of the relay can be reliably confirmed, and there is an effect that a highly reliable earthquake detection device can be provided. In particular, since the feedback circuit is independent of the output contact of the relay, a very simple circuit configuration can be achieved, and the reliability can be improved.

According to the present invention, since the feedback circuit is provided with the photocoupler, the feedback circuit can be connected to one contact relay, and the whole device can be further downsized.

[Brief description of the drawings]

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

FIG. 2 is a perspective view showing an earthquake detection device.

FIG. 3 is a sectional view taken along line AA of FIG. 2;

FIG. 4 is a plan view showing a state where a cover of the earthquake detection device is removed.

FIG. 5 is a circuit configuration diagram of the earthquake detection device.

FIG. 6 is a circuit configuration diagram of a relay interface.

FIG. 7 is a circuit configuration diagram of a relay interface according to a second embodiment of the present invention.

FIG. 8 is a block diagram showing a gas supply system using an earthquake detection device according to a third embodiment of the present invention.

FIG. 9 is a block diagram showing a gas supply system using a conventional earthquake detection device.

[Explanation of symbols]

Reference Signs List 30 semiconductor acceleration sensor (acceleration sensor) 40 arithmetic processing circuit 70 relay 71a relay drive signal 77 feedback signal 78 feedback determination unit 79 alarm unit 80 alarm signal R1, R2, R3, R4, R5, R6 resistance (feedback circuit) 81 diode ( Feedback circuit) 82 Zener diode (feedback circuit) 83 Photocoupler (feedback circuit) 84 Capacitor (feedback circuit) 86 Servo acceleration sensor (acceleration sensor) 89 Operation processing unit (operation processing circuit)

──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Hikaru Takubo 2-12-19 Shibuya, Shibuya-ku, Tokyo Inside Yamatake Honeywell Co., Ltd. (72) Inventor Yoshihisa Shimizu 2-26-3 Kahinata, Satte-shi ) Inventor Kenichi Koganemaru 5-16-5 Sakuradai, Nerima-ku, Tokyo (56) References JP-A-62-12886 (JP, A) JP-A-62-1885 (JP, A) JP-A-8-36062 (JP) , A) JP-A-9-72768 (JP, A) JP-A-57-122543 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB name) G01V 1/00 G01V 1/16 G01V 1/28 G08B 21/00

Claims (2)

(57) [Claims] 1. An acceleration sensor for detecting an acceleration, and an arithmetic processing based on a detection signal of the acceleration sensor for performing SI
An arithmetic processing circuit for calculating a value and outputting a relay drive signal for driving the relay when the SI value exceeds a predetermined threshold value, wherein the operation state of the relay is used as a feedback signal. A feedback circuit that outputs the signal; a determination unit that determines the operation state of the relay from the relay drive signal and the feedback signal; and outputs an alarm signal when the determination unit determines that the operation state of the relay is abnormal. An earthquake detection device comprising an alarm unit. 2. The earthquake detecting device according to claim 1, wherein the feedback circuit includes a photocoupler.