JP2008180532A - Distance measuring apparatus - Google Patents

Distance measuring apparatus Download PDF

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JP2008180532A
JP2008180532A JP2007012589A JP2007012589A JP2008180532A JP 2008180532 A JP2008180532 A JP 2008180532A JP 2007012589 A JP2007012589 A JP 2007012589A JP 2007012589 A JP2007012589 A JP 2007012589A JP 2008180532 A JP2008180532 A JP 2008180532A
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distance
wave
measuring device
received
time
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Susumu Fujiwara
奨 藤原
Masayuki Tokuchi
政幸 渡久地
Yasuyuki Komiya
保之 小宮
Takashi Hosaka
貴司 保坂
Mutsumi Yoshimoto
睦 吉本
Haruo Sasajima
晴男 笹島
Shigeaki Okawa
茂昭 大川
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Nihon Kentetsu Co Ltd
Mitsubishi Electric Corp
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Nihon Kentetsu Co Ltd
Mitsubishi Electric Corp
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  • Measurement Of Velocity Or Position Using Acoustic Or Ultrasonic Waves (AREA)

Abstract

<P>PROBLEM TO BE SOLVED: To provide a distance measuring apparatus capable of easily distinguishing whether received waveforms are reverberations of the time of transmission or reflected waves and accurately measuring distances even if the distance between an ultrasonic sensor and the water surface of drain water is short and reflected waves are received during the presence of reverberations of transmitted waves in the case of detecting the fullness of drain water stored in a drain water receiver by using the ultrasonic sensor as a distance measuring apparatus for measuring the distance to the surface of the drain water. <P>SOLUTION: The distance measuring apparatus is provided with a measuring device for measuring the time between the transmission and reception of ultrasonic waves as a medium for measurement and measuring distances on the basis of the measured time and starts distance measurement on the basis of received waves reflected after the termination of reverberations of transmitted waves. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

本発明は、例えば冷凍冷蔵ショーケースのドレン水の検知装置として使用される距離測定装置を使用する距離測定装置に関するものである。   The present invention relates to a distance measuring device that uses a distance measuring device that is used, for example, as a drain water detection device for a refrigerated showcase.

スーパーマーケットなどの店舗に設置されるオープンタイプの縦型冷凍冷蔵ショーケースは、図１０に示すようにショーケース本体の下部に形成される機械室３内に凝縮器２や圧縮機などにより構成される冷凍装置を配設し、ショーケース本体の背面側に設置した冷却器で冷却した冷気で商品収納庫１内に収納した商品を冷却するもので、冷気は循環される。図中６は凝縮機ファン、４はドレン水受けを示す。   An open type vertical refrigerated showcase installed in a store such as a supermarket is composed of a condenser 2 and a compressor in a machine room 3 formed at the bottom of the showcase body as shown in FIG. A refrigeration apparatus is provided to cool the product stored in the product storage 1 with the cool air cooled by the cooler installed on the back side of the showcase body, and the cool air is circulated. In the figure, 6 is a condenser fan, and 4 is a drain water receiver.

冷気は前記のように庫内の空気が循環されるものであるが、商品収納庫１の前面が商品の出入口として開放されているため、ここから暖かい外気が流入し、これに含まれる湿気が冷却器で結露し霜となる。   As described above, the cool air is circulated in the cabinet, but since the front surface of the product storage 1 is opened as a product entrance, warm outside air flows from here, and moisture contained therein is Condensation occurs in the cooler and forms frost

そして、この着霜により冷却器の能力が低下することを防ぐため、適宜除霜するが、除霜された水分がドレン水として発生する。   And in order to prevent that the capacity | capacitance of a cooler falls by this frost formation, although it defrosts suitably, the defrosted water | moisture content generate | occur | produces as drain water.

このドレン水は、通常は排水用のパイプが接続されてこのパイプで店舗外の排水溝に導かれるが、パイプが接続されるとこの配管によってショーケースの設置位置が固定される。そこで、移動が容易なように圧縮機が組み込まれているショーケースでは、移動性が損われないようドレン水もショーケース内に設置したドレンパンやドレンタンクなどのドレン水受け４に貯留している。   The drain water is usually connected to a drain pipe and led to a drain groove outside the store by this pipe. When the pipe is connected, the installation position of the showcase is fixed by this pipe. Therefore, in a showcase in which a compressor is incorporated for easy movement, drain water is also stored in a drain water receiver 4 such as a drain pan or a drain tank installed in the showcase so as not to impair mobility. .

このようにドレン水受け４にドレン水を溜める場合、定期的に排水する必要が生じるが、ドレン水の発生量は天候や、ショーケースのサイズや温度帯、庫内に収納している商品の量などによって左右される。   In this way, when drain water is stored in the drain water receiver 4, it is necessary to drain the water regularly. However, the amount of drain water generated depends on the weather, the size and temperature range of the showcase, It depends on the amount.

ドレン水の満水を検知する方法として、超音波センサーを水位センサーとして使用し、この水位センサーと水面との距離を測定することで水位を計測する方法があり、ドレン水受け４の上方に水位センサー５を設置し、ここから水面に向けて発信した超音波が水面に反射して戻り受信されるまでの時間を計測して水位センサー５と水面との距離、すなわち水位を計測するものである（例えば特許文献１参照）。
特開２００１−５９７６５号公報 As a method of detecting the fullness of drain water, there is a method of measuring the water level by measuring the distance between this water level sensor and the water surface using an ultrasonic sensor as the water level sensor. 5 is measured, and the time until the ultrasonic wave transmitted from here toward the water surface is reflected back to the water surface and received is measured to measure the distance between the water level sensor 5 and the water surface, that is, the water level ( For example, see Patent Document 1).
JP 2001-59765 A

超音波センサーを使用する方法は、図１２、図１３に示すように水位センサー５である超音波センサーの水位センサー音波発振部１１を制御するパルス発振部である送信回路部１２から発信されたパルス信号が水面で反射されて受信回路部１３に戻るまでの時間を計測し、この時間をもとに演算処理回路部１４で水位センサー５と水面との距離、すなわち水位を算出するもので、受信回路部１３はショーケースコントローラ８に接続される。   As shown in FIGS. 12 and 13, the method of using the ultrasonic sensor is a pulse transmitted from a transmission circuit unit 12 that is a pulse oscillation unit that controls the water level sensor sound wave oscillation unit 11 of the ultrasonic sensor that is the water level sensor 5. The time until the signal is reflected on the water surface and returns to the receiving circuit unit 13 is measured, and the arithmetic processing circuit unit 14 calculates the distance between the water level sensor 5 and the water surface based on this time, that is, the water level. The circuit unit 13 is connected to the showcase controller 8.

一般に超音波センサーでは、測定距離を延ばすためには超音波信号の減衰分を考慮して超音波発振素子への入力を上げ音圧を高めることが必要とされる一方で、近距離測定のためには送信波形に受信波形が重ならないよう、送信波形の影響を短くするために音圧を下げる必要がある。それでも通常PZT素子で使用できる２０ＫＨｚの周波数では駆動電圧の雑音や安定度が精度に影響して７０ｍｍ以下を正確に測定することが不可となる。   In general, in order to extend the measurement distance in an ultrasonic sensor, it is necessary to increase the sound pressure by raising the input to the ultrasonic oscillation element in consideration of the attenuation of the ultrasonic signal. In order to reduce the influence of the transmission waveform, it is necessary to lower the sound pressure so that the reception waveform does not overlap the transmission waveform. Nevertheless, at a frequency of 20 KHz that can be normally used with a PZT element, the noise and stability of the drive voltage affect the accuracy, making it impossible to accurately measure 70 mm or less.

図１４に示すように送信波形に受信波形が重なる距離は実際には８０ｍｍ程度であり、受信波形の減衰で受信確認できなくなる距離が約２００ｍｍである。これにより、正常に測定できる範囲は８０ｍｍ以上であることがわかる。   As shown in FIG. 14, the distance over which the received waveform overlaps the transmitted waveform is actually about 80 mm, and the distance at which reception cannot be confirmed due to attenuation of the received waveform is about 200 mm. Thereby, it can be seen that the range that can be normally measured is 80 mm or more.

図１１は超音波センサーを水位センサー５として使用する場合の、ドレン水受け４との関係の一例を示す正面図で、機械室３の高さは一例として３００ｍｍであり、図１４で説明した水位センサー５で正常に距離測定できる範囲を確保できる。機械室３のこの限定された高さの範囲内に水位センサー５とドレン水受け４を配置することになるが、ドレン水受け４は、水位センサー５との距離を確保するために高さの低いもの（深さの浅いもの）として例えば４０ｍｍ程度のものとする。   FIG. 11 is a front view showing an example of the relationship with the drain water receiver 4 when an ultrasonic sensor is used as the water level sensor 5. The height of the machine room 3 is 300 mm as an example, and the water level described in FIG. The range in which the distance can be normally measured by the sensor 5 can be secured. The water level sensor 5 and the drain water receiver 4 are disposed within this limited height range of the machine room 3, and the drain water receiver 4 has a height in order to secure a distance from the water level sensor 5. As a low one (shallow depth), for example, about 40 mm.

そして、ドレン水受け４の口縁を限界レベルとしてこの限界レベルと水位センサー５の超音波発信素子兼受信素子１０との距離を、超音波センサーで正常に測定できる範囲の最小限値である７０ｍｍに設定し、この限界レベルよりもさらに１０ｍｍ下方に満水レベルを設定する。   Then, with the lip of the drain water receiver 4 as a limit level, the distance between the limit level and the ultrasonic wave transmitting / receiving element 10 of the water level sensor 5 is 70 mm which is the minimum value within a range in which the ultrasonic sensor can be normally measured. And the full water level is set 10 mm below this limit level.

これにより、満水レベルが超音波センサーの発信部から８０ｍｍ離れた高さに位置し、満水レベルを正常測定可能範囲内に確実に位置させることができ、ドレン水受け４からドレン水が溢れるまで１０ｍｍの余裕を残してこの満水レベルで満水を報知するようにした。   As a result, the full water level is located at a height of 80 mm away from the transmitter of the ultrasonic sensor, and the full water level can be reliably positioned within the normal measurable range, and 10 mm until the drain water overflows from the drain water receiver 4. The full water level is reported at this full water level.

前記のように水位を測定する方法として超音波を使用し、この超音波が発信されてから戻るまでの時間を計測し、この時間を対応する信号に変換して外部に出力し、この出力をコントローラが受けて距離を算出する方法の場合、超音波センサーとドレン水受け４との距離が短く、超音波センサーで正常に測定できる範囲の最小限値である７０ｍｍよりも近いと、送信波が発信されてから反射して受信波となって戻ってくるまでの時間も短くなるため、図９に示すように送信波の残響のある間に反射波である受信波が受信され、受信波形が発信時の残響であるのか、受信波形の重なりであるのかが判別できず、正確な距離測定が困難であった。   As described above, ultrasonic waves are used as a method for measuring the water level, the time from when this ultrasonic wave is transmitted until it returns is measured, this time is converted into a corresponding signal and output to the outside. In the method of calculating the distance received by the controller, if the distance between the ultrasonic sensor and the drain water receiver 4 is short and close to 70 mm which is the minimum value of the range that can be normally measured by the ultrasonic sensor, the transmitted wave is Since the time from when the signal is transmitted to when it is reflected and returned to the received wave is shortened, the received wave that is the reflected wave is received during the reverberation of the transmitted wave as shown in FIG. It was difficult to determine whether it was reverberation at the time of transmission or overlap of received waveforms, and accurate distance measurement was difficult.

本発明の目的は前記従来例の不都合を解消し、超音波センサーを、ドレン水の水面との距離を測定する距離測定装置、すなわち水位センサーとして使用してドレン水受けに貯留したドレン水の満水を検知する場合に、超音波センサーとドレン水の水面との距離が短くて発信波の残響のある間に反射波が受信されても、受信波形が発信時の残響であるのか反射波であるのかを容易に区別でき、正確に距離測定できる距離測定装置を提供するものである。   The object of the present invention is to eliminate the disadvantages of the conventional example, and to use the ultrasonic sensor as a distance measuring device for measuring the distance from the water surface of the drain water, that is, to fill the drain water stored in the drain water receiver using the water level sensor. When the reflected wave is received while the distance between the ultrasonic sensor and the water surface of the drain water is short and the reverberation of the transmitted wave is received, the received waveform is the reverberation at the time of transmission. It is an object of the present invention to provide a distance measuring device that can easily distinguish between the two and accurately measure the distance.

本発明は前記目的を達成するため、請求項１記載の発明は、測定用の媒体としての超音波を発信してから受信するまでの時間を計測し、この計測された時間により距離を測定する測定器に距離測定装置において、発信波の残響がなくなって後に、反射してくる受信波による距離測定を開始することを特徴とするものである。   In order to achieve the above object, the invention according to claim 1 measures the time from when an ultrasonic wave as a measurement medium is transmitted until it is received, and measures the distance based on the measured time. In the distance measuring device of the measuring instrument, after the reverberation of the transmitted wave disappears, the distance measurement by the reflected wave that is reflected is started.

以上述べたように本発明の距離測定方法は、超音波センサーを水位センサーとして使用してドレン水受けに貯留したドレン水の満水を検知する場合に、送信波の残響が無くなってから、距離測定を開始するから、反射してくる受信波を送信波の残響と区別でき、正確な距離測定が行えるものである。   As described above, the distance measurement method according to the present invention uses the ultrasonic sensor as a water level sensor to detect the fullness of the drain water stored in the drain water receiver, and the distance measurement is performed after the reverberation of the transmission wave disappears. Therefore, the reflected reception wave reflected can be distinguished from the reverberation of the transmission wave, and accurate distance measurement can be performed.

以下、図面について本発明の実施形態を詳細に説明する。図１は本発明の距離測定方法の第１実施形態を示す距離測定動作のフローチャートで、本発明が実施されるショーケースの全体構成は図１０について説明した従来例と同様であるから同一の参照符号を付してここでの詳細な説明は省略する。   Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a flowchart of a distance measuring operation showing the first embodiment of the distance measuring method of the present invention. The entire configuration of the showcase in which the present invention is implemented is the same as that of the conventional example described with reference to FIG. Reference numerals are assigned and detailed description thereof is omitted.

本発明の距離測定装置は、測定手段として超音波センサーによる水位センサー５を使用するものであり、図４に示すように超音波発信素子兼受信素子１０と制御部１７とを内蔵し、制御部１７の出力側に超音波発信回路１５を介して超音波発信素子兼受信素子１０が接続され、入力側に超音波受信回路１６を介して超音波発信素子兼受信素子１０が接続される。図中１８は外部出力用のコネクタを示す。   The distance measuring device of the present invention uses a water level sensor 5 by an ultrasonic sensor as a measuring means, and as shown in FIG. 4, an ultrasonic transmitting / receiving element 10 and a control unit 17 are built in, and a control unit The ultrasonic transmitter / receiver element 10 is connected to the output side of 17 via the ultrasonic transmitter circuit 15, and the ultrasonic transmitter / receiver element 10 is connected to the input side via the ultrasonic receiver circuit 16. In the figure, reference numeral 18 denotes an external output connector.

前記水位センサー５を使用してドレン水と水位センサー５との距離を測定するには、基本構成としては、超音波発信素子兼受信素子１０からドレン水受け４内のドレン水の水面に向って発信された超音波が、水面で反射して超音波発信素子兼受信素子１０に戻ったとき、超音波受信回路１６を介して発信されてから受信されるまでの時間が制御部１７に入力され、制御部１７ではこの時間をもとにして距離データを算出し、コネクタ１８に出力する。   In order to measure the distance between the drain water and the water level sensor 5 using the water level sensor 5, as a basic configuration, from the ultrasonic wave transmitting / receiving element 10 toward the drain water surface in the drain water receiver 4. When the transmitted ultrasonic wave is reflected by the water surface and returned to the ultrasonic wave transmitting / receiving element 10, the time from when it is transmitted through the ultrasonic wave receiving circuit 16 until it is received is input to the control unit 17. The control unit 17 calculates distance data based on this time and outputs it to the connector 18.

このように、受信波は距離データに変換されるものであるが、この場合、図１のフローチャートに示すように、まず、超音波発信素子兼受信素子１０からの周波数４０ｋＨｚ、１０サイクル＝２５０ｍｓｅｃでの超音波の発信開始後（ステップ１）、受信電圧が０．１Ｖまで一旦下がってから（ステップ２）、距離測定のためのピーク電圧検出を開始する（ステップ３）。   Thus, the received wave is converted into distance data. In this case, as shown in the flowchart of FIG. 1, first, the frequency from the ultrasonic wave transmitting / receiving element 10 is 40 kHz, 10 cycles = 250 msec. After the transmission of the ultrasonic wave is started (step 1), the reception voltage is once lowered to 0.1 V (step 2), and then peak voltage detection for distance measurement is started (step 3).

図９に示すように、受信電圧が０．１Ｖまで下がった時点は、発信波の残響に受信波が重なっていたとしても、その影響がなくなった時点であり、これにより発信波の残響がなくなってからピーク電圧の検出、受信波検出を開始できる。   As shown in FIG. 9, when the reception voltage drops to 0.1V, even if the reception wave overlaps the reverberation of the transmission wave, the influence is eliminated, and thus the reverberation of the transmission wave disappears. After that, peak voltage detection and reception wave detection can be started.

ピーク電圧検出開始後、０．５ｍｓｅｃの経過後（ステップ４）、ピーク電圧が０．１Ｖ以上になれば（ステップ５）、反射した受信波が検出されたことであり、この受信波の応答時間を検出し（ステップ６）、時間と距離との相関関係に基づいて距離を算出し（ステップ７）、この距離データをコネクタ１８から出力する（ステップ８）。   After the elapse of 0.5 msec after the start of peak voltage detection (step 4), if the peak voltage becomes 0.1 V or higher (step 5), the reflected reception wave is detected, and the response time of this reception wave Is detected (step 6), the distance is calculated based on the correlation between time and distance (step 7), and this distance data is output from the connector 18 (step 8).

一方、前記（ステップ５）の段階で０．５ｍｓｅｃが経過しても測定されるピーク電圧が０．１Ｖ以上にならなければ、距離は２００ｍｍ以上の遠距離と判断する（ステップ９）。   On the other hand, if the measured peak voltage does not become 0.1 V or more even after 0.5 msec has passed in the stage of (Step 5), the distance is determined to be a long distance of 200 mm or more (Step 9).

図２は、第２実施形態のフローチャートを示し、水面と水位センサー５との距離が近い場合で、送信波の残響のある間に反射波が受信され、残響に受信波が重なった場合に、残響と区別して受信波を検出する方法である。   FIG. 2 shows a flowchart of the second embodiment. When the distance between the water surface and the water level sensor 5 is short, a reflected wave is received during the reverberation of the transmitted wave, and the received wave overlaps the reverberation. In this method, received waves are detected separately from reverberation.

前記第１実施形態と同様にまず、超音波発信素子兼受信素子１０からの周波数４０ｋＨｚ、１０サイクル＝２５０ｍｓｅｃでの超音波の発信開始後（ステップ１０）、受信電圧が０．１Ｖまで下がった時点を検出し（ステップ１１）、この時点が発信停止後から３００ｍｓｅｃ以上経過していれば（ステップ１２）、水位センサー５と水面との距離は短くなく通常の距離測定を行う（ステップ１３）。   As in the first embodiment, first, after the transmission of ultrasonic waves at a frequency of 40 kHz, 10 cycles = 250 msec from the ultrasonic transmission / reception element 10 (step 10), the reception voltage drops to 0.1V. Is detected (step 11), and if 300 msec or more has elapsed after the stop of transmission (step 12), the distance between the water level sensor 5 and the water surface is not short and normal distance measurement is performed (step 13).

前記（ステップ１１）（ステップ１２）の段階で、受信電圧が０．１Ｖまで下がった時点の、発信停止後からの時間を３００ｍｓｅｃと設定したのは、通常の残響時間が２５０ｍｓｅｃであり、発信停止後３００ｍｓｅｃを経過していれば通常は受信電圧は０．１Ｖにまで低下していることによる。   The reason for setting the time after the stop of transmission at the time when the reception voltage is reduced to 0.1 V in the stage of (Step 11) and (Step 12) is 300 msec, because the normal reverberation time is 250 msec, and the transmission is stopped. If 300 msec has passed, the reception voltage is normally lowered to 0.1V.

よって、発信停止後３００ｍｓｅｃを経過している時点で受信電圧が０．１Ｖにまで低下していれば、残響に受信波が重なっていないことになり、通常の距離測定が継続される。   Therefore, if the reception voltage has decreased to 0.1 V when 300 msec has elapsed after the transmission is stopped, the reception wave does not overlap with reverberation, and normal distance measurement is continued.

一方、図９にも示すように、受信電圧が０．１Ｖにまで低下した時点が、発信停止後３００ｍｓｅｃ以上経過した後であれば（ステップ１２）、残響に受信波が重なっていて、水位が水位センサー５に近く、水面との距離が７５ｍｍ以下と判定する（ステップ１４）。   On the other hand, as shown in FIG. 9, if the time when the reception voltage is reduced to 0.1 V is after 300 msec or more has elapsed after the transmission is stopped (step 12), the received wave overlaps the reverberation and the water level is It is determined to be close to the water level sensor 5 and the distance from the water surface is 75 mm or less (step 14).

なお、前記残響時間は装置の製作段階で予め水位センサー５の制御部１７に記憶させておくこともできる。図３は記憶のためのフローチャート、図４は制御ブロック図を示し、水位センサー５の制御部１７内の記憶部１７ａにテスト用入力部１９を接続する。   The reverberation time may be stored in advance in the control unit 17 of the water level sensor 5 at the manufacturing stage of the apparatus. FIG. 3 is a flowchart for storage, and FIG. 4 is a control block diagram. The test input unit 19 is connected to the storage unit 17 a in the control unit 17 of the water level sensor 5.

そして、超音波発信素子兼受信素子１０からの周波数４０ｋＨｚ、１０サイクル＝２５０ｍｓｅｃでの超音波の発信開始後、受信電圧が０．１Ｖまで下がった時点を検出し、発信停止後に受信電圧が０．１Ｖまで下がった時までの時間を計測してこの経過時間例えば３００ｍｓｅｃを入力部１９から記憶部１７ａに入力して予め記憶させておく（ステップ１６）。   Then, after the transmission of ultrasonic waves at the frequency of 40 kHz and 10 cycles = 250 msec from the ultrasonic transmission element / reception element 10 is started, a time point when the reception voltage is reduced to 0.1 V is detected. The time until the voltage drops to 1 V is measured, and this elapsed time, for example, 300 msec, is input from the input unit 19 to the storage unit 17a and stored in advance (step 16).

図５は第３実施形態を示し、第２実施形態と同様に、水面と水位センサー５との距離が近い場合で、送信波の残響のある間に反射波が受信され、残響に受信波が重なった場合に、残響と区別して受信波を検出する別の方法である。   FIG. 5 shows a third embodiment. Similar to the second embodiment, when the distance between the water surface and the water level sensor 5 is short, a reflected wave is received during the reverberation of the transmitted wave, and the received wave is generated in the reverberation. This is another method for detecting a received wave in distinction from reverberation when they overlap.

これは図９に示すように残響の波形に反射波の波形が重なると、残響波形の電圧値が低下している途中で、反射波が重なるために反射波によって電圧値が上昇する。これにより電圧値の変化に上下が生じ、途中に谷間が発生する。第３実施形態はこの谷間（くびれ）を検出して残響と受信波との重なりを検出するものである。   As shown in FIG. 9, when the waveform of the reflected wave overlaps the waveform of the reverberation, the voltage value increases due to the reflected wave because the reflected wave overlaps while the voltage value of the reverberant waveform is decreasing. As a result, the voltage value changes vertically, and a valley occurs in the middle. In the third embodiment, this valley (necking) is detected to detect the overlap between the reverberation and the received wave.

その具体的方法は、まず、超音波発信素子兼受信素子１０からの周波数４０ｋＨｚ、１０サイクル＝２５０ｍｓｅｃでの超音波の発信開始後、受信電圧が１Ｖ以下に下がった時点（図９におけるＡ点）の検出後（ステップ１７）、受信電圧がそのまま低下して（ステップ１８）、０．１Ｖ以下になれば（ステップ１９）、残響に受信波は重なっていないと判断して通常の距離測定が継続される（ステップ２０）。   The specific method is as follows. First, when the transmission voltage from the ultrasonic wave transmitting / receiving element 10 is 40 kHz, 10 cycles = 250 msec, and the reception voltage is lowered to 1 V or less (point A in FIG. 9). After detection (step 17), the received voltage decreases as it is (step 18), and when it becomes 0.1 V or less (step 19), it is determined that the received wave does not overlap with reverberation, and normal distance measurement continues. (Step 20).

一方、受信電圧が１Ｖ以下に下がった時点（図９におけるＡ点）の検出後（ステップ１７）、受信電圧が１Ｖ以上に上昇すれば（ステップ１８）、電圧値に上下変化が生じており、このＡ点のくびれにより残響に受信波が重なっていて、水位が水位センサー５に近く、水面との距離が７５ｍｍ以下と判定する（ステップ２１）。   On the other hand, if the reception voltage rises to 1 V or more after the detection (Step A in FIG. 9) when the reception voltage has dropped to 1 V or less (point A in FIG. 9) (step 18), the voltage value has changed up and down. It is determined that the received wave overlaps the reverberation due to the constriction at the point A, the water level is close to the water level sensor 5, and the distance from the water surface is 75 mm or less (step 21).

図６、図７は第４実施形態を示し、水面と水位センサー５との距離が極めて近距離で、発信波の残響と反射してきた受信波とが完全に重なってしまい、前記図９に示すようなくびれ（Ａ点）も無いような場合に、受信波を検出して距離を測定する方法である。   FIGS. 6 and 7 show a fourth embodiment, where the distance between the water surface and the water level sensor 5 is very short, and the reverberation of the transmitted wave and the reflected received wave completely overlap with each other, as shown in FIG. This is a method of measuring the distance by detecting the received wave when there is no such a constriction (point A).

かかる場合は、図７に示すように超音波受信回路１６に制御部１７からゲイン調整指示信号を出力し、超音波受信回路１６の受信感度を時間経過とともに上げていくようにする。   In such a case, as shown in FIG. 7, a gain adjustment instruction signal is output from the control unit 17 to the ultrasonic wave receiving circuit 16 so that the reception sensitivity of the ultrasonic wave receiving circuit 16 increases with time.

受信波は再度反射して反射波となって受信されるが、反射の回数が増すに従い、すなわち時間経過とともに減衰していく。そこで、時間経過とともに受信感度を上げて、反射波を検出しやすくする。   The received wave is reflected again and received as a reflected wave, but attenuates as the number of reflections increases, that is, with time. Therefore, the reception sensitivity is increased with the passage of time to make it easier to detect the reflected wave.

また、１回目の反射波は残響と重なって検出されない場合でも、２回目の反射波は検出されるから、この２回目の反射波の反射時間をもとに距離を測定することが可能である。しかし、この場合、超音波受信回路１６で検出された反射波（受信波）が１回目のものであるのか２回目のものであるのかを判別する必要がある。   Even if the first reflected wave is not detected due to reverberation, since the second reflected wave is detected, the distance can be measured based on the reflection time of the second reflected wave. . However, in this case, it is necessary to determine whether the reflected wave (received wave) detected by the ultrasonic wave receiving circuit 16 is the first wave or the second wave.

第４実施形態はこのような検出による測定方法であり、図６のフローチャートについて測定動作を説明する。（ステップ１）から（ステップ５）までは第１実施形態と同様であり、ピーク電圧検出が開始されてから検出されたピーク電圧が０．１Ｖ以上であれば、減衰されていない受信波が検出されたものとして、一回目の反射としてとらえ、図１のフローチャートの（ステップ６）以降の処理がなされる（ステップ２２）。   The fourth embodiment is a measurement method based on such detection, and the measurement operation will be described with reference to the flowchart of FIG. The steps from (Step 1) to (Step 5) are the same as in the first embodiment, and if the detected peak voltage is 0.1 V or more after the peak voltage detection is started, an undamped received wave is detected. As a result, it is regarded as the first reflection, and the processing after (Step 6) in the flowchart of FIG. 1 is performed (Step 22).

これに対して、（ステップ５）の段階で検出された受信波のピーク電圧が０．１Ｖ以下の場合で、さらに０．３Ｖ以上の場合は（ステップ２３）、２回目の反射波であると判断して距離測定する（ステップ２４）。ここでピーク電圧を０．１Ｖに設定したのは、受信波が２回目以降の反射によるものである場合は、反射により電圧が減衰してピーク電圧が０．１Ｖに達しないからである。   On the other hand, when the peak voltage of the received wave detected at the stage of (Step 5) is 0.1 V or less, and when it is 0.3 V or more (Step 23), it is the second reflected wave. Judging and measuring the distance (step 24). Here, the reason why the peak voltage is set to 0.1 V is that when the received wave is caused by the second and subsequent reflections, the voltage is attenuated by the reflection and the peak voltage does not reach 0.1 V.

そして、２回目の反射波は、反射波が最初に発信されてから受信されるまで水面との間を往復しているため、往復信号となって、実際の距離に対応する時間の２倍の時間が計測される。よって、計測された時間の２分の１の時間をもとにして距離を算出する。   And since the reflected wave of the 2nd time is reciprocating between the water surfaces until the reflected wave is first transmitted and received, it becomes a reciprocating signal, which is twice the time corresponding to the actual distance. Time is measured. Therefore, the distance is calculated based on the half of the measured time.

なお、前記（ステップ２３）の段階でピーク電圧が０．３Ｖ以下の場合は、受信波はノイズであると判断し、距離は２００ｍｍ以上とする（ステップ２５）。   If the peak voltage is 0.3 V or less at the stage of (Step 23), it is determined that the received wave is noise, and the distance is 200 mm or more (Step 25).

図８は水面と水位センサー５との間が近距離の場合、近距離例えば７５〜５０ｍｍでの反射波の測定精度を集中的に上げるための方法であり、水位センサー５の側に、水面から反射してきた反射波を再度、超音波発信素子兼受信素子１０に向けて反射させるような手段として凹面部２０を、超音波発信素子兼受信素子１０の周囲に形成した。   FIG. 8 shows a method for intensively increasing the measurement accuracy of reflected waves at a short distance, for example, 75 to 50 mm, when the distance between the water surface and the water level sensor 5 is short. A concave portion 20 was formed around the ultrasonic wave transmitting / receiving element 10 as a means for reflecting the reflected wave reflected again toward the ultrasonic transmitting / receiving element 10.

これにより、水面で一旦反射した反射波は凹面部２０に当り、ここで超音波発信素子兼受信素子１０の方向に向けて再度反射するから、超音波発信素子兼受信素子１０での反射波の捕捉精度を向上できる。   Thereby, the reflected wave once reflected on the water surface hits the concave surface portion 20 and is reflected again in the direction of the ultrasonic transmitting element / receiving element 10, so that the reflected wave of the ultrasonic transmitting element / receiving element 10 is reflected. Capturing accuracy can be improved.

本発明の距離測定装置の第１実施形態を示す距離測定動作のフローチャートである。It is a flowchart of the distance measurement operation | movement which shows 1st Embodiment of the distance measurement apparatus of this invention. 本発明の距離測定装置の第２実施形態を示す距離測定動作のフローチャートである。It is a flowchart of the distance measurement operation | movement which shows 2nd Embodiment of the distance measurement apparatus of this invention. 本発明の距離測定装置の第２実施形態を示す残響時間測定動作のフローチャートである。It is a flowchart of the reverberation time measurement operation | movement which shows 2nd Embodiment of the distance measuring device of this invention. 本発明の距離測定装置の第２実施形態を示す制御ブロック図である。It is a control block diagram which shows 2nd Embodiment of the distance measuring device of this invention. 本発明の距離測定装置の第３実施形態を示す距離測定動作のフローチャートである。It is a flowchart of the distance measurement operation | movement which shows 3rd Embodiment of the distance measurement apparatus of this invention. 本発明の距離測定装置の第４実施形態を示す距離測定動作のフローチャートである。It is a flowchart of the distance measurement operation | movement which shows 4th Embodiment of the distance measurement apparatus of this invention. 本発明の距離測定装置の第４実施形態を示す制御ブロック図である。It is a control block diagram which shows 4th Embodiment of the distance measuring device of this invention. 本発明の距離測定装置の第４実施形態を示す水位センサーの説明図である。It is explanatory drawing of the water level sensor which shows 4th Embodiment of the distance measuring device of this invention. 本発明の距離測定装置の残響時間と反射波との関係を示す波形図である。It is a wave form diagram which shows the relationship between the reverberation time and reflected wave of the distance measuring device of this invention. ドレン水検知装置を備えた冷凍冷蔵ショーケースの斜視図である。It is a perspective view of the freezer / refrigeration showcase provided with the drain water detection apparatus. ドレン水検知装置の正面図である。It is a front view of a drain water detection apparatus. 水位センサーの制御ブロック図である。It is a control block diagram of a water level sensor. 水位センサーの波形図である。It is a wave form diagram of a water level sensor. 水位センサーによる測定可能範囲を示すグラフである。It is a graph which shows the measurable range by a water level sensor.

符号の説明Explanation of symbols

１ 商品収納庫 ２ 凝縮器
３ 機械室 ４ ドレン水受け
５ 水位センサー ６ 凝縮機ファン
７ 蒸発板 ８ ショーケースコントローラ
９ 満水警報ランプ １０ 超音波発信素子兼受信素子
１１ 水位センサー音波発振部 １２ 送信回路部
１３ 受信回路部 １４ 演算処理回路部
１５ 超音波発信回路 １６ 超音波受信回路
１７ 制御部 １８ コネクタ
１７ａ 記憶部
１９ テスト用入力部 ２０ 凹面部 DESCRIPTION OF SYMBOLS 1 Commodity storage 2 Condenser 3 Machine room 4 Drain water receptacle 5 Water level sensor 6 Condenser fan 7 Evaporating plate 8 Showcase controller 9 Full water warning lamp 10 Ultrasonic transmitter / receiver 11 Water level sensor sound wave generator 12 Transmitter circuit unit DESCRIPTION OF SYMBOLS 13 Reception circuit part 14 Arithmetic processing circuit part 15 Ultrasonic transmission circuit 16 Ultrasonic reception circuit 17 Control part 18 Connector 17a Memory | storage part 19 Test input part 20 Concave surface part

Claims (8)

測定用の媒体としての超音波を発信してから受信するまでの時間を計測し、この計測された時間により距離を測定する測定器を備えた距離測定装置において、発信波の残響がなくなって後に、反射してくる受信波による距離測定を開始することを特徴とする距離測定装置。   In a distance measuring device equipped with a measuring instrument that measures the distance from the transmission of an ultrasonic wave as a measurement medium until it is received, the reverberation of the transmitted wave disappears later. A distance measuring device that starts distance measurement using reflected received waves. 前記測定用の媒体の反射を所定時間内に受信できない場合は、測定対象が測定範囲よりも遠方に存在すると判断することを特徴とする請求項１記載の距離測定装置。   2. The distance measuring apparatus according to claim 1, wherein when the reflection of the measurement medium cannot be received within a predetermined time, it is determined that the measurement object exists farther than the measurement range. 測定用の媒体としての超音波を発信してから受信するまでの時間を計測し、この計測された時間により距離を測定する測定器を備えた距離測定装置において、発信波の通常の残響時間経過後、所定時間をさらに経過した後に受信される受信電圧が所定値にはじめて低下したことが検出されたときは、この初めて所定値に低下した受信波を測定対象から反射してきた反射波と判断し、発信波の残響とは区別し、測定対象が近距離にあると判断することを特徴とする距離測定装置。   In a distance measurement device equipped with a measuring device that measures the distance from when an ultrasonic wave is transmitted as a measurement medium to when it is received, the normal reverberation time of the transmitted wave has elapsed Thereafter, when it is detected that the reception voltage received after a predetermined time has further decreased to the predetermined value for the first time, the received wave that has decreased to the predetermined value for the first time is determined as the reflected wave reflected from the measurement target. A distance measuring device that distinguishes from the reverberation of a transmitted wave and determines that a measurement object is at a short distance. 前記発信波の残響時間を予め測定し、この残響時間データを測定器の記憶部に予め格納しておくことを特徴とする請求項３記載の距離測定装置。   4. The distance measuring apparatus according to claim 3, wherein the reverberation time of the transmitted wave is measured in advance, and the reverberation time data is stored in advance in a storage unit of the measuring device. 測定用の媒体としての超音波を発信してから受信するまでの時間を計測し、この計測された時間により距離を測定する測定器を備えた距離測定装置において、音波発信後、受信波電圧が初めて所定値に低下するまでの間に検出される受信電圧の上下動変化をもって、初めて所定値に低下した受信波を測定対象から反射してきた反射波と判断し、発信波の残響とは区別し、測定対象が近距離にあると判断することを特徴とする距離測定装置。   In a distance measuring device equipped with a measuring device that measures the distance from when an ultrasonic wave is transmitted as a measurement medium to when it is received, the received wave voltage is The received wave that has fallen to the predetermined value for the first time is judged as the reflected wave that has been reflected from the object to be measured, and is distinguished from the reverberation of the transmitted wave. A distance measuring device that judges that a measurement object is at a short distance. 測定用の媒体としての超音波を発信してから受信するまでの時間を計測し、この計測された時間により距離を測定する測定器を備えた距離測定装置において、超音波を受信する受信部の感度を時間経過とともに変化させることを特徴とする距離測定装置。   In a distance measuring device equipped with a measuring device that measures a distance from transmission of an ultrasonic wave as a measurement medium to reception thereof, and measuring the distance based on the measured time, a receiving unit that receives the ultrasonic wave A distance measuring device that changes sensitivity with time. 測定用の媒体としての超音波を発信してから受信するまでの時間を計測し、この計測された時間により距離を測定する測定器を備えた距離測定装置において、超音波を受信する受信部での受信電圧が所定値よりも小さい場合、超音波の反射による２回目の往復信号としてこの往復時間をもとに距離を測定することを特徴とする距離測定装置。   In a distance measuring apparatus equipped with a measuring device that measures the distance from transmission of an ultrasonic wave as a measurement medium to reception thereof, and measuring the distance based on the measured time, a receiving unit that receives the ultrasonic wave When the received voltage is smaller than a predetermined value, the distance is measured based on the round trip time as a second round trip signal by reflection of ultrasonic waves. 前記測定器は、測定対象から反射してきた測定用媒体を、再度、測定対象に反射させて受信部に導く機能を備えることを特徴とする請求項７記載の距離測定装置。   The distance measuring device according to claim 7, wherein the measuring device has a function of reflecting the measurement medium reflected from the measurement object again to the measurement object and guiding the measurement medium to the reception unit.
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JPWO2021019769A1 (en) * 2019-08-01 2021-11-11 三菱電機株式会社 Side obstacle detector

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