Omron Corporation

Masakazu Suzuki

Naotsugu Ueda

Hiroyuki Mino

A seismic sensor according to one or more embodiments may include: an acceleration measuring unit configured to repeatedly measure acceleration in three directions orthogonal to each other; and an index value calculator configured to operate in a measurement mode for calculating an index value of a magnitude of an earthquake based on a measurement result of acceleration in at least one direction by the acceleration measuring unit, and to operate in a standby mode with less power consumption than power consumption in the measurement mode. Then, the acceleration measuring unit monitors establishment of an activation condition that N times (M≥N≥2) measurement results in consecutive M times (M≥2) measurement results of acceleration in a predetermined direction exceed an acceleration threshold value. When the acceleration measuring unit detects establishment of the activation condition, the index value calculator transitions from the standby mode to the measurement mode.

Seismic sensor and sensor control method

A seismic sensor includes a measurement unit configured to measure acceleration; an earthquake determination unit configured to determine whether or not an earthquake has occurred based on the acceleration measured in a predetermined determination period; an index calculator configured to calculate an index value indicating a scale of an earthquake in an earthquake processing period after the predetermined determination period, when the earthquake determination unit determines that an earthquake has occurred; a continuous earthquake determination unit configured to determine whether or not an earthquake has occurred, based on the acceleration measured in the earthquake processing period; and a shut-off determination unit configured to inhibit output of the shut-off signal regardless of the index value when the continuous earthquake determination unit determines that no earthquake has occurred.

Seismic sensor and earthquake determination method

Provided is a technique that can more reliably suppress erroneous determination of noise as an earthquake, in a seismic sensor. The seismic sensor operates in a power saving mode and a measurement mode with higher power consumption than that of the power saving mode. The seismic sensor includes: a measurement unit configured to measure acceleration; an earthquake determination unit configured to determine whether or not an earthquake has occurred based on the acceleration measured in a predetermined determination period after shifting to the measurement mode when shifting from the power saving mode to the measurement mode in a case where acceleration measured by the measurement unit exceeds a predetermined threshold; and an index calculator configured to calculate an index value indicating a scale of an earthquake in an earthquake processing period after the predetermined determination period, when the earthquake determination unit determines that an earthquake has occurred. The earthquake determination unit determines an occurrence of an earthquake based on the presence or absence of a pulse waveform in a waveform of acceleration measured in the determination period, and/or a frequency characteristic or a convergence characteristic after the pulse waveform in a waveform of the acceleration.

Provided is a technique that can suppress erroneous determination of noise as an earthquake in a seismic sensor and erroneous output of a shut-off signal. The seismic sensor includes: an earthquake determination unit configured to determine an occurrence of an earthquake based on acceleration measured in a determination period after shifting from a power saving mode to a measurement mode with higher power consumption when measured acceleration exceeds a predetermined threshold; and an index calculator configured to calculate an index value indicating a scale of an earthquake in an earthquake processing period after the determination period, when the earthquake determination unit determines that an earthquake has occurred. The seismic sensor causes output of a shut-off signal when the index value is equal to or larger than a threshold in the earthquake processing period. The seismic sensor further includes: a continuous earthquake determination unit configured to determine whether or not an earthquake has occurred, based on acceleration measured in the earthquake processing period; and a shut-off determination unit configured to inhibit output of the shut-off signal regardless of the index value when the continuous earthquake determination unit determines that no earthquake has occurred.

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Takatsuki, Japan

Masakazu Suzuki