JP2004227106A - Glass breakage sensor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a glass breakage sensor capable of automatically restoring from an operation confirmation mode for confirming an operation to a general mode for performing a general operation. <P>SOLUTION: This sensor comprises a piezoelectric element 1 for converting the vibration of a glass plate to an electric signal, and a determination means 2 for outputting a breakage detection signal according to the output of the piezoelectric element 1. This sensor further comprises a switching means for alternately switching the general mode in which the determination means 2 outputs the breakage detection signal when the output of the piezoelectric element 1 corresponds to a vibration involved by breakage of the glass plate and the operation confirmation mode in which the determination means 2 outputs the breakage detection signal when the output of the piezoelectric element 1 corresponds to a vibration not involved by breakage of the glass plate. This sensor also comprises a timer restoration circuit 7 for measuring the elapsed time from switching to the operation confirmation mode, and restoring the operation of the determination means 2 to the general mode after the lapse of a preset restoration time. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

【００２１】
一方、動作確認モードにおいては、第２のコンデンサＣ０がコンデンサＣに並列に接続されることによりフィルタ回路２１のキャパシタンスは増大する。つまり、第２のコンデンサＣ０とスイッチＳＷ１とがキャパシタンス変更手段として機能する。動作確認モードにおけるフィルタ回路２１のカットオフ周波数ｆ’は次式２で表される。
【００２２】
【数２】

【００２３】
ここで、ガラス板が破壊されるときの圧電素子１の出力は例えば図３の曲線Ａで示すようになり、ピークを数百ｋＨｚの周波数に有する。また、ガラス板が破壊されないときの圧電素子１の出力は図３の曲線Ｂで示すようになり、ガラス板が破壊されるときよりも低い周波数にピークを有する。
【００２４】
つまり、第２のコンデンサＣ０のキャパシタンスを適当に選ぶことにより、動作確認モードにおけるフィルタ回路２１のカットオフ周波数ｆ’を低くして、圧電素子１の出力のうちガラス板が破壊されない振動の周波数の成分をフィルタ回路２１が通過させるようにすることができる。
【００２５】
上記構成によれば、使用者が動作確認モードに切り換えて動作を確認した後、通常モードに戻すのを忘れてしまっても、復帰時間が経過した後に自動的に通常モードに復帰するから、その後の誤動作の発生を防ぐことができる。
【００２６】
なお、第２のコンデンサＣ０とスイッチＳＷ１との直列回路を設ける代わりに、図４に示すようにスイッチＳＷ２と第２のインダクタＬ０との並列回路をインダクタＬに直列に接続してもよい。スイッチＳＷ２は通常モードにおいてはオン状態となり、動作確認モードにおいてはオフ状態となるように計時復帰回路７によってオンオフ制御される。つまり、動作確認モードにおいては通常モードよりもフィルタ回路２１のインダクタンスが増大する。言い換えると、スイッチＳＷ２と第２のインダクタＬ０との並列回路がインダクタンス変更手段として機能する。この構成によれば、フィルタ回路２１の動作確認モードにおけるカットオフ周波数ｆ’は次式３のように表される。
【００２７】
【数３】

【００２８】
第２のインダクタＬ０のインダクタンスを適当に選ぶことにより、先に述べたキャパシタンス変更手段と同様に、動作確認モードにおけるフィルタ回路２１のカットオフ周波数ｆ’を低くして、圧電素子１の出力のうちガラス板が破壊されない振動の周波数の成分がフィルタ回路２１を通過可能とすることができる。
【００２９】
（実施形態２）
本実施形態の基本的な構成は実施形態１と同様であるので、共通する部分については同じ符号を付して説明を省略し、異なる部分についてのみ詳細に説明する。本実施形態においては、フィルタ回路２１は圧電素子１の出力のうちガラス板が破壊されるときの固有周波数の成分を通過させるものである。また、図５に示すように、通常モードにおいてはオフ状態となり動作確認モードにおいてはオン状態となるように計時復帰回路７によってオンオフ制御されるスイッチＳＷ３と、スイッチＳＷ３がオン状態であるときにフィルタ回路２１の出力に一定値Ｖｂを加える直流電源Ｅとを備える。その他の構成は実施形態１と同様である。
【００３０】
フィルタ回路２１の出力に一定値Ｖｂを加えるということは、相対的に破壊検出閾値ＶｔｈをＶｂだげ減少させるのと同じことになる。つまり、スイッチＳＷ３と直流電源Ｅとが閾値変更手段として機能する。ここで、ガラス板が破壊されるときの固有周波数の成分は、ガラス板が破壊されない振動には少ないから、通常モードにおける破壊検出閾値Ｖｔｈはガラス板が破壊されない振動で比較回路２２が破壊検出信号を出力しないように設定されている。しかし、上記構成によれば、一定値Ｖｂの値を十分に大きくとれば、動作確認モードにおいてはガラス板が破壊されない振動でも比較回路２２が破壊検出信号を出力するようにすることができる。
【００３１】
なお、閾値変更手段は破壊検出閾値を上記のように相対的に変化させる回路に限られず、破壊検出閾値の絶対値を変更する回路としてもよい。例えば、比較回路２２はフィルタ回路２１の出力と破壊検出閾値としての参照電圧とを比較するコンパレータとし、通常モードにおける破壊検出閾値となる第１の電圧を分圧して第２の電圧を生成する分圧抵抗と、通常モードにおいては第１の電圧を参照電圧として比較回路２２に入力し動作確認モードにおいては第２の電圧を参照電圧として比較回路２２に入力するように計時復帰回路７によって切り換え制御される切り換えスイッチとを設ければよい。
【００３２】
または、閾値変更手段を用いる代わりに、図６に示すように、インダクタＬに直列に接続され通常モードにおいてはオン状態となり動作確認モードにおいてはオフ状態となるように計時復帰回路７によってオンオフ制御されるスイッチＳＷ４を設けてもよい。動作確認モードにおいてはスイッチＳＷ４によってインダクタＬが切り離され、圧電素子１の出力がフィルタ回路２１を通さずにそのまま比較回路２２に入力されるのと同じことになる。この構成を採用すれば、動作確認モードでガラス板が破壊されない振動を受けた際の比較回路２２への入力が、通常モードでガラス板が破壊されたときと同様に大きくなるから、比較回路２２に破壊検出信号を出力させることができる。
【００３３】
（実施形態３）
本実施形態の基本的な構成は実施形態１と同様であるので、共通する部分については同じ符号を付して説明を省略し、異なる部分についてのみ詳細に説明する。本実施形態は、図７に示すように、計時復帰回路７に代えて、動作確認モードに切り換えられている間に圧電素子１の出力と予め定められた復帰閾値とを比較し、圧電素子１の出力が復帰閾値よりも大きくなった回数を計数するとともに、動作確認モードに切り換えられてから圧電素子１の出力が復帰閾値よりも大きくなった回数が予め定められた復帰回数に達したときに判定手段２の動作を通常モードに復帰させる計数復帰手段としての計数復帰回路８を備える。計数復帰回路８は、計時復帰回路７と同様に、選択部６及び状態判別回路９とともに切換手段としても機能する。その他の構成は実施形態１と同様である。
【００３４】
上記構成によれば、使用者が選択部６を動作確認モードに切り換えて動作を確認した後、通常モードに戻すのを忘れてしまっても、復帰閾値よりも大きな出力を圧電素子１が復帰回数だけ発生した後に自動的に通常モードに復帰するから、その後の誤動作の発生を防ぐことができる。
【００３５】
なお、復帰回数は１回であってもよく、この場合、計数復帰回路８は実際には圧電素子１の出力が復帰閾値よりも大きくなった回数を計数する必要はない。また、通常モードと動作確認モードとで判定手段２の動作を異ならせる構成は実施形態１及び実施形態２で述べたどの構成であってもよい。
【００３６】
【発明の効果】
請求項１の発明は、建物において室内外を仕切るガラス板に取りつけられ、前記ガラス板の振動を電気信号に変換する検出手段と、前記検出手段の出力に応じて破壊検出信号を出力する判定手段とを備えるガラス破壊センサにおいて、前記検出手段の出力が前記ガラス板が破壊される時の振動に相当するときに前記判定手段が前記破壊検出信号を出力する通常モードと、前記検出手段の出力がガラス板が破壊されない振動に相当するときに前記判定手段が前記破壊検出信号を出力する動作確認モードとを択一的に切り換える切換手段と、前記動作確認モードに切り換えられてから経過した時間を計測するとともに予め設定された復帰時間が経過した後に前記判定手段の動作を前記通常モードに復帰させる計時復帰手段とを備えるので、使用者が動作確認モードに切り換えて動作を確認した後、通常モードに戻すのを忘れてしまっても、復帰時間が経過した後に自動的に通常モードに復帰するから、その後の誤動作の発生を防ぐことができる。
【００３７】
請求項２の発明は、建物において室内外を仕切るガラス板に取りつけられ、前記ガラス板の振動を電気信号に変換する検出手段と、前記検出手段の出力に応じて破壊検出信号を出力する判定手段とを備えるガラス破壊センサにおいて、前記検出手段の出力が前記ガラス板が破壊される時の振動に相当するときに前記判定手段が前記破壊検出信号を出力する通常モードと、前記検出手段の出力がガラス板が破壊されない振動に相当するときに前記判定手段が前記破壊検出信号を出力する動作確認モードとを択一的に切り換える切換手段と、前記動作確認モードに切り換えられている間に前記検出手段の出力と予め定められた復帰閾値とを比較し、前記検出手段の出力が復帰閾値よりも大きくなった回数を計数するとともに、前記動作確認モードに切り換えられてから前記検出手段の出力が復帰閾値よりも大きくなった回数が予め定められた復帰回数に達したときに前記判定手段の動作を前記通常モードに復帰させる計数復帰手段とを備えるので、使用者が動作確認モードに切り換えて動作を確認した後、通常モードに戻すのを忘れてしまっても、復帰閾値よりも大きな出力を検出手段が復帰回数だけ発生した後に自動的に通常モードに復帰するから、その後の誤動作の発生を防ぐことができる。
【００３８】
請求項３の発明は、請求項１又は請求項２の発明において、前記判定手段は、前記通常モードにおいては前記ガラス板が破壊されるときの固有周波数の成分を通過させるとともに前記動作確認モードにおいては前記ガラス板が破壊されないときの振動の周波数の成分を通過させるフィルタ手段と、予め設定された破壊検出閾値よりも前記フィルタ手段の出力が大きければ破壊検出信号を出力する比較手段とを備えるので、動作確認モードに切り換えてからガラス板が破壊されない振動を加えることによってガラスが破壊されたときと同様の動作をさせることができる。
【００３９】
請求項４の発明は、請求項３の発明において、前記フィルタ手段は、ＬＣハイパスフィルタからなり、前記動作確認モードにおいて前記フィルタ手段のキャパシタンスを前記通常モードに比べて大きくするキャパシタンス変更手段を備えるので、動作確認モードにおいて検出手段の出力のうちガラス板が破壊されない振動の周波数の成分がフィルタ手段を通過可能とすることができる。
【００４０】
請求項５の発明は、請求項３の発明において、前記フィルタ手段は、ＬＣハイパスフィルタからなり、前記動作確認モードにおいて前記フィルタ手段のインダクタンスを前記通常モードに比べて大きくするインダクタンス変更手段を備えるので、動作確認モードにおいて検出手段の出力のうちガラス板が破壊されない振動の周波数の成分がフィルタ手段を通過可能とすることができる。
【００４１】
請求項６の発明は、請求項１又は請求項２の発明において、前記判定手段は、前記検出手段の出力のうち前記ガラス板が破壊されるときの固有周波数の成分を通過させるフィルタ手段と、予め設定された破壊検出閾値よりも前記フィルタ手段の出力が大きければ破壊検出信号を出力する比較手段と、前記動作確認モードにおいて前記破壊検出閾値を前記通常モードに比べて低くする閾値変更手段とを備えるので、動作確認モードにおいては、ガラス板が破壊されない振動すなわち検出手段の出力のうち固有周波数の成分が少ない振動であっても、ガラスが破壊されたときと同様の動作をさせることができる。
【００４２】
請求項７の発明は、請求項１又は請求項２の発明において、前記判定手段は、前記検出手段の出力のうち前記ガラス板が破壊されるときの固有周波数の成分を通過させるフィルタ手段と、予め設定された破壊検出閾値よりも入力が大きければ破壊検出信号を出力する比較手段とを備え、前記通常モードにおいては前記フィルタ手段の出力が前記比較手段に入力され、前記動作確認モードにおいては前記検出手段の出力が前記フィルタ手段を通さずに前記比較手段に入力されるので、動作確認モードにおいては、ガラス板が破壊されない振動すなわち検出手段の出力のうち固有周波数の成分が少ない振動であっても、ガラスが破壊されたときと同様の動作をさせることができる。
【図面の簡単な説明】
【図１】本発明の実施形態１を示すブロック図である。
【図２】同上の要部を示す説明図である。
【図３】検出手段の出力の一例を示すグラフである。
【図４】本発明の実施形態１の別の形態の要部を示す説明図である。
【図５】本発明の実施形態２の要部を示す説明図である。
【図６】同上の別の形態の要部を示す説明図である。
【図７】本発明の実施形態３を示すブロック図である。
【図８】従来例を示すブロック図である。
【符号の説明】
１ 圧電素子
２ 判定手段
６ 選択部
７ 計時復帰回路
８ 計数復帰回路
９ 状態判別回路
２１ フィルタ回路
２２ 比較回路[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a glass breakage sensor that is attached to a glass plate that partitions indoors and outdoors in a building and detects breakage of the glass plate.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, there has been provided a glass breakage sensor for security that is attached to a glass plate such as a glass door that partitions indoors and outdoors in a building and detects breakage of the glass plate (for example, see Patent Document 1). As shown in FIG. 8, this type of glass breakage sensor includes a piezoelectric element 1 for detecting vibration of a glass plate, a determination unit 2 for outputting a breakage detection signal in accordance with the output of the piezoelectric element 1, and a power on / off. And a power switch 3. The destruction detection signal is used, for example, as a trigger for driving the alarm unit 5 that generates an alarm with sound or light by the alarm drive circuit 4.
[0003]
The determination means 2 includes a filter circuit 21 that passes a component of a natural frequency that is a frequency at which a peak occurs when the glass plate is broken out of the output of the piezoelectric element 1, and an output of the filter circuit 21 and a predetermined breakage. A comparison circuit that compares the detection threshold value Vth and outputs a destruction detection signal if the output of the filter circuit is greater than the destruction detection threshold value Vth.
[0004]
Here, in order to prevent malfunction due to mere vibration that does not break the glass plate, such as vibration when opening and closing the glass door, the frequency of the output of the piezoelectric element 1 at which the peak occurs in the vibration that does not break the glass plate is output. The components are blocked by the filter circuit 21. For this reason, it was difficult to simply confirm the operation of the glass breakage sensor by vibrating the glass plate. Therefore, the normal mode in which the determination means 2 outputs a break detection signal when the output of the piezoelectric element 1 corresponds to the vibration when the glass sheet is broken, and the output of the piezoelectric element 1 corresponds to the vibration in which the glass sheet is not broken. There has been proposed a glass breakage sensor provided with switching means (not shown) for selectively switching between an operation check mode in which the judgment means 2 outputs a breakage detection signal when the judgment is made. In this glass breakage sensor, the operation can be confirmed without breaking the glass plate by switching the switching means to the operation check mode and vibrating the glass plate.
[0005]
[Patent Document 1]
JP-A-2000-46268 (pages 3 to 5, FIG. 5)
[0006]
[Problems to be solved by the invention]
However, since the switching means is generally provided at an inconspicuous position, the user sometimes forgets to return to the normal mode after switching to the operation confirmation mode and confirming the operation. Further, a switch common to the power switch 3 may be used as the switching means. In this case, when the user turns on the power, the place where the normal mode should be set may be mistakenly set as the operation check mode. Was. If the glass plate is left as it is in the operation check mode, malfunctions due to vibrations that do not destroy the glass plate have frequently occurred.
[0007]
The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a glass breakage sensor that can automatically return to a normal mode in which a normal operation is performed from an operation check mode for checking an operation. is there.
[0008]
[Means for Solving the Problems]
The invention according to claim 1, wherein the detecting means is attached to a glass plate partitioning a room inside and outside in a building, and converts a vibration of the glass plate into an electric signal, and outputs a destruction detection signal according to an output of the detecting means. In the glass breakage sensor comprising: a normal mode in which the determination unit outputs the breakage detection signal when an output of the detection unit corresponds to vibration when the glass sheet is broken, and an output of the detection unit. Switching means for selectively switching between an operation check mode in which the determination means outputs the break detection signal when the vibration corresponds to vibration in which the glass sheet is not broken; and measuring a time elapsed since switching to the operation check mode. And a clock return unit that returns the operation of the determination unit to the normal mode after a preset return time has elapsed. That.
[0009]
The invention according to claim 2, wherein the detection means is attached to a glass plate partitioning the interior and exterior of the building and converts vibration of the glass plate into an electric signal, and a determination means for outputting a destruction detection signal in accordance with an output of the detection means. In the glass breakage sensor comprising: a normal mode in which the determination unit outputs the breakage detection signal when an output of the detection unit corresponds to vibration when the glass sheet is broken, and an output of the detection unit. Switching means for selectively switching between an operation check mode in which the determination means outputs the break detection signal when the vibration corresponds to vibration in which the glass sheet is not broken; and the detecting means while the operation mode is switched to the operation check mode. Is compared with a predetermined return threshold value, and the number of times that the output of the detection means becomes larger than the return threshold value is counted, and the operation check mode is checked. Counting return means for returning the operation of the determination means to the normal mode when the number of times the output of the detection means has become larger than the return threshold after being switched has reached a predetermined number of return times. Features.
[0010]
According to a third aspect of the present invention, in the first or second aspect of the present invention, the determination means allows a natural frequency component at the time of breaking the glass sheet to pass in the normal mode, and to determine in the operation check mode. Comprises filter means for passing a component of the frequency of vibration when the glass sheet is not broken, and comparing means for outputting a break detection signal if the output of the filter means is greater than a predetermined break detection threshold. It is characterized by.
[0011]
According to a fourth aspect of the present invention, in the third aspect of the present invention, the filter means comprises an LC high-pass filter, and further comprises a capacitance changing means for increasing the capacitance of the filter means in the operation check mode as compared with the normal mode. It is characterized by.
[0012]
According to a fifth aspect of the present invention, in the third aspect of the present invention, the filter means comprises an LC high-pass filter, and has an inductance changing means for increasing the inductance of the filter means in the operation check mode as compared with the normal mode. It is characterized by.
[0013]
According to a sixth aspect of the present invention, in the first or second aspect of the present invention, the determination unit includes a filter unit that passes a component of a natural frequency when the glass plate is broken out of an output of the detection unit, Comparing means for outputting a destruction detection signal if the output of the filter means is larger than a preset destruction detection threshold; and threshold changing means for lowering the destruction detection threshold in the operation check mode compared to the normal mode. It is characterized by having.
[0014]
According to a seventh aspect of the present invention, in the first or second aspect of the present invention, the determination unit includes a filter unit that passes a component of a natural frequency when the glass plate is broken out of the output of the detection unit; A comparison means for outputting a destruction detection signal if the input is larger than a preset destruction detection threshold, wherein in the normal mode, the output of the filter means is input to the comparison means, and in the operation confirmation mode, The output of the detection means is input to the comparison means without passing through the filter means.
[0015]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[0016]
(Embodiment 1)
In the present embodiment, as shown in FIG. 1, a piezoelectric element 1 as a detecting means for converting vibration of a glass plate into an electric signal, and a judging means 2 for outputting a destruction detection signal in accordance with the output of the piezoelectric element 1 Prepare. In addition, an alarm unit 5 that generates a sound or light for notifying the breakage of the glass plate and an alarm drive circuit 4 that drives the alarm unit 5 using a breakage detection signal as a trigger are provided.
[0017]
The operation of the judging means 2 includes a normal mode in which a breakage detection signal is output when the output of the piezoelectric element 1 corresponds to the vibration when the glass sheet is broken, and a vibration in which the output of the piezoelectric element 1 does not break the glass sheet. And an operation check mode in which a destruction detection signal is output when the state corresponds to. And a selection unit 6 for selectively selecting the operation of the determination unit 2 by a user operation, and a state determination circuit for determining the state of the selection unit 6 and generating an output according to the state of the selection unit 6 9 and a timing recovery circuit 7 for switching the operation of the determination means 2 according to the output of the state determination circuit 9. That is, the selection unit 6, the clock recovery circuit 7, and the state determination circuit 9 function as switching means. The timer recovery circuit 7 measures the time elapsed since the selector 6 was switched to the operation check mode, and returns the operation of the determination means 2 to the normal mode after the preset recovery time has elapsed. It also works as a means.
[0018]
The judging means 2 is a filter as a filter means that passes a natural frequency component when the glass sheet is broken in the normal mode and passes a frequency component of vibration when the glass sheet is not broken in the operation check mode. The circuit includes a circuit 21 and a comparison circuit 22 as comparison means for outputting a destruction detection signal when the output of the filter circuit 21 is larger than a preset destruction detection threshold Vth.
[0019]
The filter circuit 21 is, for example, an LC high-pass filter having a capacitor C connected in series to the piezoelectric element 1 and an inductor L connected in parallel to a series circuit of the piezoelectric element 1 and the capacitor C as shown in FIG. Further, a series circuit of the second capacitor C0 and the switch SW1 is connected to the capacitor C in parallel. The switch SW1 is turned on / off by the clock recovery circuit 7 so as to be turned off in the normal mode and turned on in the operation check mode. In the normal mode, since the capacitor C0 is not connected, the cutoff frequency f of the filter circuit 21 is represented by the following equation 1.
[0020]
(Equation 1)

[0021]
On the other hand, in the operation check mode, the capacitance of the filter circuit 21 is increased by connecting the second capacitor C0 in parallel with the capacitor C. That is, the second capacitor C0 and the switch SW1 function as capacitance changing means. The cutoff frequency f ′ of the filter circuit 21 in the operation check mode is expressed by the following equation (2).
[0022]
(Equation 2)

[0023]
Here, the output of the piezoelectric element 1 when the glass plate is broken is as shown by a curve A in FIG. 3, for example, and has a peak at a frequency of several hundred kHz. The output of the piezoelectric element 1 when the glass sheet is not broken is as shown by the curve B in FIG. 3, and has a peak at a lower frequency than when the glass sheet is broken.
[0024]
That is, by appropriately selecting the capacitance of the second capacitor C0, the cutoff frequency f 'of the filter circuit 21 in the operation check mode is reduced, and the frequency of the vibration of the output of the piezoelectric element 1 at which the glass sheet is not broken is selected. The components can be passed by the filter circuit 21.
[0025]
According to the above configuration, even if the user switches to the operation check mode and checks the operation, and forgets to return to the normal mode, the user automatically returns to the normal mode after the return time elapses. Can be prevented from malfunctioning.
[0026]
Instead of providing a series circuit of the second capacitor C0 and the switch SW1, a parallel circuit of the switch SW2 and the second inductor L0 may be connected in series to the inductor L as shown in FIG. The switch SW2 is turned on and off by the timer reset circuit 7 so as to be turned on in the normal mode and turned off in the operation check mode. That is, in the operation check mode, the inductance of the filter circuit 21 is larger than in the normal mode. In other words, a parallel circuit of the switch SW2 and the second inductor L0 functions as an inductance changing unit. According to this configuration, the cutoff frequency f ′ in the operation check mode of the filter circuit 21 is expressed by the following equation 3.
[0027]
[Equation 3]

[0028]
By appropriately selecting the inductance of the second inductor L0, the cutoff frequency f 'of the filter circuit 21 in the operation check mode is reduced, and the output of the piezoelectric element 1 is reduced. A component of the frequency of the vibration that does not break the glass plate can pass through the filter circuit 21.
[0029]
(Embodiment 2)
Since the basic configuration of the present embodiment is the same as that of the first embodiment, common parts are denoted by the same reference numerals, description thereof will be omitted, and only different parts will be described in detail. In the present embodiment, the filter circuit 21 passes a component of a natural frequency of the output of the piezoelectric element 1 when the glass plate is broken. Further, as shown in FIG. 5, a switch SW3 which is turned on / off by a time reset circuit 7 so as to be turned off in the normal mode and turned on in the operation check mode, and a filter when the switch SW3 is turned on. A DC power supply E for applying a constant value Vb to the output of the circuit 21. Other configurations are the same as in the first embodiment.
[0030]
Adding a constant value Vb to the output of the filter circuit 21 is equivalent to relatively reducing the destruction detection threshold Vth by Vb. That is, the switch SW3 and the DC power supply E function as threshold changing means. Here, since the component of the natural frequency when the glass sheet is broken is small in the vibration that does not break the glass sheet, the break detection threshold Vth in the normal mode is the vibration that does not break the glass sheet, and the comparison circuit 22 is the vibration that does not break the glass sheet. Is set not to output. However, according to the above configuration, if the value of the constant value Vb is set to a sufficiently large value, the comparison circuit 22 can output the destruction detection signal even in the vibration in which the glass sheet is not broken in the operation check mode.
[0031]
Note that the threshold changing means is not limited to the circuit that relatively changes the destruction detection threshold as described above, and may be a circuit that changes the absolute value of the destruction detection threshold. For example, the comparison circuit 22 is a comparator that compares an output of the filter circuit 21 with a reference voltage as a destruction detection threshold, and divides a first voltage that is a destruction detection threshold in the normal mode to generate a second voltage. Switching control by the timing recovery circuit 7 such that the first voltage is input to the comparison circuit 22 as a reference voltage in the normal mode and the second voltage is input to the comparison circuit 22 as the reference voltage in the operation check mode. And a changeover switch to be provided.
[0032]
Alternatively, instead of using the threshold value changing means, as shown in FIG. 6, the on / off control is performed by the timer reset circuit 7 so as to be connected in series with the inductor L and turned on in the normal mode and turned off in the operation check mode. A switch SW4 may be provided. In the operation check mode, the inductor L is disconnected by the switch SW4, and the output of the piezoelectric element 1 is directly input to the comparison circuit 22 without passing through the filter circuit 21. With this configuration, the input to the comparison circuit 22 when the glass plate is subjected to vibration that does not break the glass in the operation check mode becomes as large as when the glass plate is broken in the normal mode. Can output a destruction detection signal.
[0033]
(Embodiment 3)
Since the basic configuration of the present embodiment is the same as that of the first embodiment, common parts are denoted by the same reference numerals, description thereof will be omitted, and only different parts will be described in detail. In the present embodiment, as shown in FIG. 7, the output of the piezoelectric element 1 is compared with a predetermined return threshold while the operation mode is switched to the operation check mode, instead of the time resetting circuit 7, and the piezoelectric element 1 When the number of times that the output of the piezoelectric element 1 has become larger than the return threshold after switching to the operation check mode has reached the predetermined number of returns, A count return circuit 8 is provided as count return means for returning the operation of the determination means 2 to the normal mode. The count return circuit 8 also functions as a switching unit together with the selection unit 6 and the state determination circuit 9, similarly to the clock return circuit 7. Other configurations are the same as in the first embodiment.
[0034]
According to the above configuration, even if the user switches the selection unit 6 to the operation check mode and checks the operation, and forgets to return to the normal mode, the piezoelectric element 1 outputs an output larger than the reset threshold even if the user forgets to return to the normal mode. Since the normal mode is automatically restored after the occurrence of the error, the occurrence of a subsequent malfunction can be prevented.
[0035]
The number of times of return may be one. In this case, the count return circuit 8 does not actually need to count the number of times that the output of the piezoelectric element 1 has become larger than the return threshold. Further, the configuration for making the operation of the determination unit 2 different between the normal mode and the operation check mode may be any of the configurations described in the first and second embodiments.
[0036]
【The invention's effect】
The invention according to claim 1, wherein the detecting means is attached to a glass plate partitioning a room inside and outside in a building, and converts a vibration of the glass plate into an electric signal, and outputs a destruction detection signal according to an output of the detecting means. In the glass breakage sensor comprising: a normal mode in which the determination unit outputs the breakage detection signal when an output of the detection unit corresponds to vibration when the glass sheet is broken, and an output of the detection unit. Switching means for selectively switching between an operation check mode in which the determination means outputs the break detection signal when the vibration corresponds to vibration in which the glass sheet is not broken; and measuring a time elapsed since switching to the operation check mode. And a time resetting means for returning the operation of the determining means to the normal mode after a preset return time has elapsed. Even if the user switches to the operation check mode and checks the operation and forgets to return to the normal mode, the device automatically returns to the normal mode after the return time elapses, so that subsequent malfunctions can be prevented. .
[0037]
The invention according to claim 2, wherein the detection means is attached to a glass plate partitioning the interior and exterior of the building and converts vibration of the glass plate into an electric signal, and a determination means for outputting a destruction detection signal in accordance with an output of the detection means. In the glass breakage sensor comprising: a normal mode in which the determination unit outputs the breakage detection signal when an output of the detection unit corresponds to vibration when the glass sheet is broken, and an output of the detection unit. Switching means for selectively switching between an operation check mode in which the determination means outputs the break detection signal when the vibration corresponds to vibration in which the glass sheet is not broken; and the detecting means while the operation mode is switched to the operation check mode. Is compared with a predetermined return threshold value, and the number of times that the output of the detection means becomes larger than the return threshold value is counted, and the operation check mode is checked. Count return means for returning the operation of the determination means to the normal mode when the number of times the output of the detection means has become greater than the return threshold after being switched has reached a predetermined return number, Even if the user switches to the operation check mode and checks the operation, and forgets to return to the normal mode, the output automatically returns to the normal mode after the detection means has generated an output larger than the return threshold the number of times returned. Therefore, occurrence of a subsequent malfunction can be prevented.
[0038]
According to a third aspect of the present invention, in the first or second aspect of the present invention, the determination means allows a natural frequency component at the time of breaking the glass sheet to pass in the normal mode, and to determine in the operation check mode. Is provided with filter means for passing a component of the frequency of vibration when the glass sheet is not broken, and comparing means for outputting a break detection signal if the output of the filter means is larger than a predetermined break detection threshold. By switching to the operation check mode and then applying a vibration that does not break the glass plate, the same operation as when the glass is broken can be performed.
[0039]
According to a fourth aspect of the present invention, in the third aspect of the present invention, the filter means comprises an LC high-pass filter and includes a capacitance changing means for increasing the capacitance of the filter means in the operation check mode as compared with the normal mode. In the operation check mode, the component of the frequency of the vibration that does not destroy the glass plate in the output of the detection means can be allowed to pass through the filter means.
[0040]
According to a fifth aspect of the present invention, in the third aspect, the filter means includes an LC high-pass filter and includes an inductance changing means for increasing the inductance of the filter means in the operation check mode as compared with the normal mode. In the operation check mode, the component of the frequency of the vibration that does not destroy the glass plate in the output of the detection means can be allowed to pass through the filter means.
[0041]
According to a sixth aspect of the present invention, in the first or second aspect of the present invention, the determination unit includes a filter unit that passes a component of a natural frequency when the glass plate is broken out of an output of the detection unit, Comparing means for outputting a destruction detection signal if the output of the filter means is larger than a preset destruction detection threshold; and threshold changing means for lowering the destruction detection threshold in the operation check mode compared to the normal mode. In the operation check mode, the same operation as when the glass is broken can be performed in the operation check mode even if the vibration does not break the glass plate, that is, the vibration having a small natural frequency component in the output of the detecting means.
[0042]
According to a seventh aspect of the present invention, in the first or second aspect of the present invention, the determination unit includes a filter unit that passes a component of a natural frequency when the glass plate is broken out of the output of the detection unit; A comparison means for outputting a destruction detection signal if the input is larger than a preset destruction detection threshold, wherein in the normal mode, the output of the filter means is input to the comparison means, and in the operation confirmation mode, Since the output of the detection means is input to the comparison means without passing through the filter means, in the operation check mode, the vibration is such that the glass sheet is not broken, that is, the output of the detection means has a small natural frequency component. Also, the same operation as when the glass is broken can be performed.
[Brief description of the drawings]
FIG. 1 is a block diagram showing a first embodiment of the present invention.
FIG. 2 is an explanatory diagram showing a main part of the above.
FIG. 3 is a graph showing an example of an output of a detection unit.
FIG. 4 is an explanatory diagram showing a main part of another embodiment of the first embodiment of the present invention.
FIG. 5 is an explanatory diagram illustrating a main part of a second embodiment of the present invention.
FIG. 6 is an explanatory diagram showing a main part of another embodiment of the present invention.
FIG. 7 is a block diagram showing a third embodiment of the present invention.
FIG. 8 is a block diagram showing a conventional example.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Piezoelectric element 2 Judgment means 6 Selection part 7 Time recovery circuit 8 Count recovery circuit 9 State determination circuit 21 Filter circuit 22 Comparison circuit

Claims (7)

In a glass breakage sensor, which is attached to a glass plate partitioning a room inside and outside in a building, the detection unit converts vibration of the glass plate into an electric signal, and a determination unit that outputs a breakage detection signal in accordance with an output of the detection unit. A normal mode in which the determination means outputs the breakage detection signal when the output of the detection means corresponds to the vibration when the glass sheet is broken, and the output of the detection means is changed to a vibration in which the glass sheet is not broken. Switching means for selectively switching between an operation check mode in which the determination means outputs the destruction detection signal at a corresponding time; and measuring a time elapsed since switching to the operation check mode and returning to a preset state. Time-return means for returning the operation of the determination means to the normal mode after a lapse of time. . In a glass breakage sensor, which is attached to a glass plate partitioning a room inside and outside in a building, the detection unit converts vibration of the glass plate into an electric signal, and a determination unit that outputs a breakage detection signal in accordance with an output of the detection unit. A normal mode in which the determination means outputs the breakage detection signal when the output of the detection means corresponds to the vibration when the glass sheet is broken, and the output of the detection means is changed to a vibration in which the glass sheet is not broken. Switching means for selectively switching between an operation check mode in which the determination means outputs the destruction detection signal when corresponding, and an output of the detection means which is predetermined while being switched to the operation check mode. A comparison is made with the return threshold value, and the number of times that the output of the detection means has become larger than the return threshold value is counted, and whether the mode has been switched to the operation check mode is determined. Glass comprising: a count return unit that returns the operation of the determination unit to the normal mode when the number of times the output of the detection unit becomes larger than a return threshold reaches a predetermined return count. Destruction sensor. In the normal mode, the determination unit is configured to pass a component of a natural frequency when the glass sheet is broken, and to pass a component of a vibration frequency when the glass sheet is not broken in the operation check mode. 3. The glass breakage sensor according to claim 1, further comprising: a unit; and a comparison unit that outputs a breakage detection signal when an output of the filter unit is greater than a predetermined breakage detection threshold. 4. The glass breakage sensor according to claim 3, wherein the filter unit includes an LC high-pass filter, and further includes a capacitance changing unit that increases a capacitance of the filter unit in the operation check mode as compared with the normal mode. 4. The glass breakage sensor according to claim 3, wherein the filter unit includes an LC high-pass filter, and further includes an inductance changing unit that increases the inductance of the filter unit in the operation check mode as compared with the normal mode. The determination unit includes a filter unit that passes a component of a natural frequency when the glass sheet is broken out of the output of the detection unit, and a breakage unit when the output of the filter unit is larger than a preset breakage detection threshold. 3. The glass breakage sensor according to claim 1, further comprising: a comparison unit that outputs a detection signal; and a threshold value change unit that lowers the breakage detection threshold in the operation check mode as compared with the normal mode. . The determination unit includes a filter unit that passes a component of a natural frequency when the glass plate is broken out of the output of the detection unit, and outputs a breakage detection signal if an input is larger than a predetermined breakage detection threshold value. The output of the filter unit is input to the comparison unit in the normal mode, and the output of the detection unit is input to the comparison unit without passing through the filter unit in the operation check mode. The glass breakage sensor according to claim 1 or 2, wherein

Images