JPH0137686B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to improvements in a device for sensing earthquakes.

Earthquake sensing devices consist of a seismic sensor that senses vibrations and emits an output, and a processing circuit that processes the output of the seismic sensor. In order to check the operation of the seismic sensor and the processing circuit, it is necessary to apply mechanical vibration to the seismic sensor.

However, if the seismic sensor is fixed to a building,
Or if it is buried underground, it is not easy to check its operation.

An object of the present invention is to provide an earthquake sensing device that allows the operation of a seismic sensor to be confirmed without applying mechanical vibration to the seismic sensor.

An embodiment of the present invention will be described below with reference to FIGS. 1 and 2.

In the figure, reference numeral 1 denotes a moving coil type earthquake sensor, which includes a permanent magnet 1a, a moving coil 1b movably arranged between its magnetic poles, and a spring 1c supporting the moving coil 1b.
It consists of 2 is a current generation circuit that generates a predetermined direct current, 3 is an automatic reset type changeover switch, 4 is a processing circuit, 5 is a filter circuit that shapes the input waveform, 6 is a reference voltage circuit that generates a reference voltage, and 7 is a Comparator 8 is an output relay.

The changeover switch 3 is always in contact with the terminal a.

When an earthquake occurs, the moving coil 1b vibrates depending on the seismic intensity. The moving coil 1b is a permanent magnet 1
Since it oscillates within the magnetic field of a, it generates an alternating voltage. This output is given to a filter circuit 5 via a changeover switch 3, where the waveform is shaped. The maximum value of this waveform is compared with a reference voltage in a comparator 7, and if it is larger than the reference voltage, the comparator 7 issues an output and the output relay 8 is energized. If the voltage is below the reference voltage, the comparator 7 will not output an output and the output relay 8 will not be energized. Activating the output relay 8 means that an earthquake has been detected. In this way, earthquake detection is performed.

Next, when it is desired to check the operation of the seismic sensor 1 and the processing circuit 4 under normal conditions, the changeover switch 3 is turned to the terminal b side. The seismic sensor 1 is now connected to the current generating circuit 2, and a direct current flows through the moving coil 1b. Therefore, the movable coil 1b is displaced by a certain amount.
If the user releases the selector switch 3, the selector switch 3 automatically returns to contact the terminal a. Since the movable coil 1b is disconnected from the current generating circuit 2, it returns to its original position and vibrates under the action of the spring 1c, producing an output as described above. If the amount of displacement of the moving coil 1b by the current generating circuit 2 is selected to be sufficiently large,
Since the output relay 8 is energized, the operation of the seismic sensor 1 and the processing circuit 4 can be confirmed.

In the above-mentioned embodiment, a self-resetting switch is usually provided in the middle of the output signal line for supplying the output signal from the seismic sensor 1 to the processing circuit 4, and this switch is normally left open. A DC power supply is connected to the contact 3b which is in the normally closed state, and a processing circuit 4 is connected to the contact 3a which is normally closed.
Therefore, the operation of the conventional seismic sensor 1 can be verified without any special modification. In other words, the output signal line connecting the seismic sensor 1 and the processing circuit 4 is also used as a vibration-applying power supply line for operation confirmation. The container can be used as is.

Moreover, only an electric wire corresponding to an output signal line is connected to the moving coil. Therefore, for example, if the electric wire for supplying power to give vibration is further connected to the movable part, the number of electric wires increases, which generates resistance force when moving against the movable part and causes a decrease in sensitivity. It is possible to prevent this structure from occurring, and it is possible to check the operation of the seismic sensor while maintaining its high sensitivity.

In this invention, a seismic sensor that utilizes the vibration of a moving coil placed in a magnetic field is fixed to a building or buried underground, and a changeover switch is connected to an electric path between the seismic sensor and a processing circuit. After the moving coil is connected to the DC power supply, the changeover switch automatically returns to switch to the processing circuit, so special modifications to add mechanical vibration to the seismic sensor (such as adding an excitation coil, etc.) are required. ) without adding
The seismic sensor can be forcibly operated with the same structure, and the operation of the earthquake sensing device can be confirmed with an overall simple configuration.

Moreover, since there is no need to modify the moving coil of the seismic sensor, that is, add more electric wires, etc., the device can be used to confirm operation while maintaining high sensitivity without causing a decrease in sensitivity. It is something.

[Brief explanation of drawings]

FIG. 1 is a block circuit diagram showing an embodiment of an earthquake sensing device according to the present invention, and FIG. 2 is a diagram showing the principle of the seismic sensor shown in FIG. 1... Seismic sensor, 1a... Permanent magnet, 1b... Moving coil, 1c... Spring, 2... Current generating circuit (DC power supply), 3... Selector switch, 4... Processing circuit, Identical parts inside are indicated by the same reference numerals.

Claims (1)

[Claims] 1. A seismic sensor having a moving coil placed in a magnetic field and supported by a spring is fixed to a building or buried underground, and when the moving coil vibrates, the moving coil generates an output corresponding to the vibration. , in which the processing circuit outputs an output when this output is larger than a predetermined value, a DC power source that generates a DC current, and when operated, the movable coil is connected to the DC power source, and when the operation is canceled, An earthquake sensing device comprising: a changeover switch that operates to automatically return to switch the seismic sensor to the processing circuit, and is inserted and connected to an electric line connecting the seismic sensor and the processing circuit.