ABNORMALITY DETECTION DEVICE AND ABNORMALITY DETECTION METHOD

To enable an abnormality in an ultrasonic flowmeter to be detected earlier than before.SOLUTION: The present invention comprises: a received signal acquisition unit 401 and a received signal acquisition unit 402 for acquiring a received signal; a zero-cross point measurement unit 403 and a zero-cross point measurement unit 404 for measuring a time till a zero-cross point multiple times for each of a plurality of unit measurement steps; a time difference calculation unit 405 for calculating a time difference between measurement results from the zero-cross point measurement unit 403 and measurement results from the zero-cross point measurement unit 404; an average value calculation unit 406 for calculating the average value of time differences at a first-half zero-cross point; an average value calculation unit 407 for calculating the average value of time differences at a latter-half zero-cross point; a difference calculation unit 408 for calculating the absolute value of the difference between calculation results from the average value calculation unit 406 and calculation results from the average value calculation unit 407; and an abnormality detection unit 409 for comparing the absolute value of the difference calculated by the difference calculation unit 408 with a threshold so as to detect an abnormality in an ultrasonic flowmeter.SELECTED DRAWING: Figure 2 【課題】従来に対し、早期に超音波流量計の異常を検知可能とする。【解決手段】受信信号を取得する受信信号取得部４０１及び受信信号取得部４０２と、複数の単位計測工程毎に、ゼロクロス点までの時間を複数回計測するゼロクロス点計測部４０３及びゼロクロス点計測部４０４と、ゼロクロス点計測部４０３による計測結果とゼロクロス点計測部４０４による計測結果との時間差を算出する時間差算出部４０５と、前半ゼロクロス点での時間差の平均値を算出する平均値算出部４０６と、後半ゼロクロス点での時間差の平均値を算出する平均値算出部４０７と、平均値算出部４０６による算出結果と平均値算出部４０７による算出結果との差分の絶対値を算出する差分算出部４０８と、差分算出部４０８により算出された差分の絶対値を閾値と比較することで、超音波流量計の異常を検知する異常検知部４０９とを備えた。【選択図】図２