JP2006211186A - Photoelectric sensor with interference prevention function - Google Patents

Photoelectric sensor with interference prevention function Download PDF

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JP2006211186A
JP2006211186A JP2005019337A JP2005019337A JP2006211186A JP 2006211186 A JP2006211186 A JP 2006211186A JP 2005019337 A JP2005019337 A JP 2005019337A JP 2005019337 A JP2005019337 A JP 2005019337A JP 2006211186 A JP2006211186 A JP 2006211186A
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interference
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interference light
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JP4579704B2 (en
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Koji Honda
幸司 本田
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SICK OPTEX KK
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Abstract

<P>PROBLEM TO BE SOLVED: To provide a photoelectric sensor with an interference prevention function capable of preventing the mutual interference of the plurality of photoelectric sensors, and shortening projection delay time as much as possible in response to the high speed measurement of an object. <P>SOLUTION: A plurality of stages of interference light detection levels is provided in a plurality of stages of interference light detection timings before the termination of an object detection timing. A plurality of stages of projection delay time is provided in response to the levels. The optimum delay time corresponding to the temporal detection state of interference light is given, so that the useless delay time is eliminated. Then, the projection delay time is shortened as much as possible as a whole, so as to correspond to the high speed measurement. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

本発明は、物体を検出する光電センサが複数配置されている場合に、各光電センサの干渉防止機能に関する。   The present invention relates to an interference prevention function of each photoelectric sensor when a plurality of photoelectric sensors for detecting an object are arranged.

一般に、光電センサは、検出物体が搬送された状態で、投光素子からの投光ビームで照射された検出物体の反射光を受光素子で受光させ、この受光した受光信号を増幅回路で増幅して、比較回路（コンパレータ）によって所定のしきい値と比較して、例えば物体の有無を検出する。複数の方向または位置から物体を検出する場合には、複数の光電センサを並列配置する必要がある。この場合、１つの光電センサの投光素子の出力を開始させる物体検知タイミング（投光タイミング）の終了前に他の光電センサの投光に基づく反射光（干渉光）を受光することにより、相互干渉を生じるおそれがある。   In general, a photoelectric sensor receives reflected light of a detection object irradiated with a light projection beam from a light projecting element with a light receiving element while the detected object is conveyed, and amplifies the received light reception signal with an amplifier circuit. Then, for example, the presence or absence of an object is detected by comparison with a predetermined threshold by a comparison circuit (comparator). When detecting an object from a plurality of directions or positions, it is necessary to arrange a plurality of photoelectric sensors in parallel. In this case, by receiving reflected light (interference light) based on the projection of the other photoelectric sensor before the end of the object detection timing (projection timing) for starting the output of the projection element of one photoelectric sensor, May cause interference.

このため、従来から、干渉光を受光した光電センサの物体検知タイミングを所定の遅延時間だけ遅らせて、各光電センサの相互干渉を防止する種々の提案がなされている。この例として、光電センサの投光タイミングを当該光電センサの同期タイミング制御手段に設定された所定時間で決定することにより、所定時間を干渉防止に必要な時間よりも長く確保して相互干渉を防止するもの（例えば、特許文献１）、１の光電センサの投光タイミングと他の光電センサからの干渉光との重なり状態に応じて、各光電センサの投光タイミングをそれぞれ異なるずらしパターンでずらすことにより、相互干渉を防止するもの（例えば、特許文献２）が知られている。   For this reason, various proposals have been made to prevent mutual interference between the photoelectric sensors by delaying the object detection timing of the photoelectric sensor that has received the interference light by a predetermined delay time. As an example of this, by determining the light projection timing of the photoelectric sensor at a predetermined time set in the synchronization timing control means of the photoelectric sensor, the predetermined time is secured longer than the time necessary for preventing interference to prevent mutual interference. What to do (for example, Patent Document 1) According to the overlapping state of the light projection timing of one photoelectric sensor and the interference light from another photoelectric sensor, the light projection timing of each photoelectric sensor is shifted with a different shift pattern. (For example, patent document 2) which prevents mutual interference is known.

一方、複数の検知レベルを設けて、干渉光が受光素子に入射されない期間を有効に利用して検出動作を行ない、各検知レベルに応じた遅延時間だけ遅らせて、一律の遅延時間としないことにより、干渉防止率の向上を図るものが知られている（例えば、特許文献３）。
特開平９−８３３３０号公報 特開２００３−１９４９６２号公報 特開平６−１６９２４８号公報 On the other hand, by providing a plurality of detection levels and performing the detection operation effectively using the period in which the interference light is not incident on the light receiving element, by delaying by the delay time according to each detection level, it is not a uniform delay time. A device that improves the interference prevention rate is known (for example, Patent Document 3).
JP-A-9-83330 JP 2003-19462 A JP-A-6-169248

しかし、検出物体が高速で搬送された状態で物体を検出する高速測定の場合、相互干渉を防止するだけでなく、干渉光に対する遅延時間をできるだけ短くする必要があるが、特許文献１、２では遅延時間を短縮することができず、特許文献３のように複数の検知レベルに対して複数の遅延時間を設けたものでも、全体の遅延時間の短縮に限界があり、いずれも高速測定への対応が困難であった。すなわち、従来では、高速測定に対応して可及的に全体の投光遅延時間を短縮できる光電センサを実現できなかった。   However, in the case of high-speed measurement in which an object is detected with the detection object being conveyed at high speed, it is necessary not only to prevent mutual interference but also to reduce the delay time for interference light as much as possible. Even if the delay time cannot be shortened and a plurality of delay times are provided for a plurality of detection levels as in Patent Document 3, there is a limit to shortening the overall delay time, and all of them are suitable for high-speed measurement. The response was difficult. That is, conventionally, it has not been possible to realize a photoelectric sensor capable of shortening the entire light projection delay time as much as possible in response to high-speed measurement.

本発明は、前記の問題点を解決して、複数の光電センサの相互干渉を防止し、かつ物体の高速測定に対応して可及的に投光遅延時間を短縮することを可能とした干渉防止機能付き光電センサを提供することを目的とする。   The present invention solves the above-described problems, prevents mutual interference of a plurality of photoelectric sensors, and enables interference delay time to be shortened as much as possible in response to high-speed measurement of an object. An object is to provide a photoelectric sensor with a prevention function.

前記目的を達成するために、本発明にかかる干渉防止機能付き光電センサは、投光素子を出力させて投光ビームを照射させる駆動回路と、投光ビームで照射された物体からの反射光を受光した受光素子からの受光信号を増幅する増幅回路と、投光素子の出力を開始させる物体検知タイミングで、増幅された受光信号の電圧と物体検知しきい値との比較に基づき、物体検知信号を出力する比較回路とを備えたものであって、前記比較回路は、さらに前記物体検知タイミングの終了前に複数段階設けられた干渉光検知タイミングで、増幅された受光信号の電圧と、前記干渉光検知タイミングごとに複数段階設けられた干渉光検知レベルをもつ干渉光検知しきい値との比較に基づき干渉光検知信号を出力するものであり、前記干渉光検知信号の干渉光検知タイミングにおける干渉光検知レベルに基づき、これに応じて複数設けられた投光遅延時間から所定の投光遅延時間を出力する干渉制御部と、前記所定の投光遅延時間だけ遅延された物体検知タイミングで前記投光素子を出力させるように前記駆動回路を制御する投光制御部とを備えている。   In order to achieve the above object, a photoelectric sensor with an interference preventing function according to the present invention includes a driving circuit that outputs a light projecting element to irradiate a light projecting beam, and reflected light from an object irradiated with the light projecting beam. Based on a comparison between the amplification circuit that amplifies the received light signal from the received light receiving element and the object detection timing that starts the output of the light projecting element, the voltage of the amplified light reception signal and the object detection threshold The comparator circuit further outputs a voltage of the received light signal amplified at the interference light detection timing provided in a plurality of stages before the end of the object detection timing, and the interference signal. An interference light detection signal is output based on a comparison with an interference light detection threshold having interference light detection levels provided in a plurality of stages for each light detection timing, and interference of the interference light detection signal is performed. Based on the interference light detection level at the detection timing, an interference control unit that outputs a predetermined projection delay time from a plurality of projection delay times provided in response thereto, and object detection delayed by the predetermined projection delay time A light projecting control unit that controls the drive circuit to output the light projecting element at a timing.

この構成によれば、物体検知タイミングの終了前での複数段階の干渉光検知タイミングにおける複数段階の干渉光検知レベルを設け、これに応じて複数段階の投光遅延時間を設けているので、従来のように複数段階の干渉光検知レベルおよび投光遅延時間だけを設けたのと異なり、これに複数段階の干渉光検知タイミングを加味して検知していることから、干渉光検知信号の干渉光検知タイミングにおける干渉光検知レベル、つまり干渉光の経時的な検知状態に応じた最適な遅延時間を与えるので、無駄な遅延時間がなくなり、全体として可及的に投光遅延時間を短縮することができ、高速測定に対応可能となる。   According to this configuration, a plurality of stages of interference light detection levels are provided at a plurality of stages of interference light detection timing before the end of the object detection timing, and accordingly, a plurality of stages of light projection delay time are provided. Unlike the case where only multiple levels of interference light detection level and projection delay time are provided as shown in Fig. 5, the interference light of the interference light detection signal is detected by taking into account the multiple levels of interference light detection timing. Since the optimum delay time according to the interference light detection level at the detection timing, that is, the detection state of interference light with time, is given, unnecessary delay time is eliminated, and the light projection delay time can be shortened as much as possible as a whole. Can be used for high-speed measurement.

好ましくは、前記干渉制御部は、前記干渉光検知タイミングの複数段階、干渉光検知タイミングの各段階ごとに設けられた干渉光検知レベルの複数段階と、干渉光検知タイミングおよび干渉光検知レベルの各段階の組合せごとに設けられた複数の投光遅延時間とを記憶する設定値記憶部と、前記干渉光検知信号の干渉光検知タイミングにおける干渉光検知レベルが、前記記憶された干渉光検知タイミングにおける干渉光検知レベルの各段階に該当する場合に、これら各段階の組合せに応じた所定の投光遅延時間を前記投光制御部に出力する遅延時間出力部とを備えている。   Preferably, the interference control unit includes a plurality of stages of the interference light detection timing, a plurality of stages of interference light detection levels provided for each stage of the interference light detection timing, and each of the interference light detection timing and the interference light detection level. A set value storage unit that stores a plurality of light projection delay times provided for each combination of stages, and an interference light detection level at the interference light detection timing of the interference light detection signal is set at the stored interference light detection timing. A delay time output unit that outputs a predetermined light projection delay time corresponding to a combination of these steps to the light projection control unit when corresponding to each step of the interference light detection level;

以下、本発明の実施形態を図面にしたがって説明する。図１は、本発明の一実施形態に係る干渉防止機能付き光電センサを示す構成図である。本センサは、投光素子１と、投光素子１を出力させて投光ビームを照射させる駆動回路２と、投光ビームで照射された検出物体Ｍからの反射光を受光する受光素子３と、受光素子３で受光した受光信号を増幅する増幅回路５と、物体Ｍを検知するために投光素子１の出力を開始させる物体検知タイミングで、増幅回路５により増幅された受光信号の電圧と所定しきい値とを比較する比較回路（コンパレータ）６、およびカウンタ回路１１を有する制御部（ＣＰＵ）７と、比較の結果に基づき例えば検出物体Ｍの有無（ＯＮ、ＯＦＦ）を出力する出力回路８とを備えて、検出物体Ｍが搬送された状態で検出物体Ｍの有無を検出するものである。検出物体Ｍの有無のほかに、検出物体Ｍの大小や明暗などを検出してもよい。投光素子１は例えば発光ダイオード（ＬＥＤ）、受光素子３は例えばフォトダイオード（ＰＤ）が用いられる。   Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a configuration diagram illustrating a photoelectric sensor with an interference preventing function according to an embodiment of the present invention. The sensor includes a light projecting element 1, a drive circuit 2 that outputs the light projecting element 1 and emits a light projecting beam, and a light receiving element 3 that receives reflected light from the detection object M irradiated with the light projecting beam. The amplification circuit 5 for amplifying the light reception signal received by the light receiving element 3 and the voltage of the light reception signal amplified by the amplification circuit 5 at the object detection timing for starting the output of the light projecting element 1 to detect the object M A comparison circuit (comparator) 6 that compares a predetermined threshold value and a control unit (CPU) 7 having a counter circuit 11, and an output circuit that outputs, for example, the presence or absence (ON, OFF) of the detection object M based on the comparison result 8 and detects the presence or absence of the detection object M in a state where the detection object M is conveyed. In addition to the presence or absence of the detection object M, the size or brightness of the detection object M may be detected. For example, a light emitting diode (LED) is used as the light projecting element 1, and a photodiode (PD) is used as the light receiving element 3, for example.

前記制御部７は、本センサ全体を制御するもので、前記比較回路６とカウンタ回路１１のほかに、干渉光防止に関する制御を行う干渉制御部９および投光素子１に関する制御を行う投光制御部１０を有する。   The control unit 7 controls the entire sensor. In addition to the comparison circuit 6 and the counter circuit 11, an interference control unit 9 that performs control related to interference light prevention and a light projection control that performs control related to the light projecting element 1. Part 10.

前記比較回路６は、所定の検知タイミングで受光信号としきい値とを比較するものであり、前記物体検知タイミングで比較するほか、さらに物体検知タイミングの終了前に複数段階設けられた干渉光検知タイミングで、増幅された受光信号の電圧と、前記干渉光検知タイミングごとに複数段階設けられた干渉光検知レベルをもつ干渉光検知しきい値との比較に基づき干渉光検知信号を出力する。この比較回路６における複数段階の干渉光検知レベルは、後述するカウンタ回路１１を介した干渉光検知タイミングと対応して干渉制御部９により設定される。   The comparison circuit 6 compares a received light signal with a threshold value at a predetermined detection timing. In addition to the comparison at the object detection timing, interference light detection timing provided in a plurality of stages before the end of the object detection timing. Then, the interference light detection signal is output based on a comparison between the amplified light reception signal voltage and the interference light detection threshold value having interference light detection levels provided in a plurality of stages at each interference light detection timing. The interference light detection levels at a plurality of stages in the comparison circuit 6 are set by the interference control unit 9 corresponding to the interference light detection timing via the counter circuit 11 described later.

カウンタ回路１１は、比較回路６に対して検知タイミング、つまり物体検知タイミングおよび物体検知タイミング終了前に複数段階設けられた干渉光検知タイミングを与える。このカウンタ回路１１における、物体検知タイミングは制御部７により、干渉光検知タイミングは干渉制御部９により設定される。   The counter circuit 11 gives the comparison circuit 6 detection timing, that is, object detection timing and interference light detection timing provided in a plurality of stages before the end of the object detection timing. In the counter circuit 11, the object detection timing is set by the control unit 7, and the interference light detection timing is set by the interference control unit 9.

前記干渉制御部９は、前記干渉光検知信号の干渉光検知タイミングにおける干渉光検知レベルに基づき、これに応じて複数設けられた投光遅延時間から所定の投光遅延時間を出力する。この干渉制御部９は、設定値記憶部（設定値記憶メモリ）１２と投光遅延時間出力部１４とを備えている。設定値記憶メモリ１２は、干渉光検知タイミングの複数段階を記憶する記憶部２１および干渉光検知タイミングの各段階ごとに設けられた干渉光検知レベルの複数段階を記憶する記憶部２２と、干渉光検知タイミングおよび干渉光検知レベルの各段階の組合せごとに設けられた複数の投光遅延時間を記憶する記憶部２３とを備えている。これらの設定値は予め記憶させておいてもよいし、外部入力により設定するようにしてもよい。   Based on the interference light detection level at the interference light detection timing of the interference light detection signal, the interference control unit 9 outputs a predetermined light projection delay time from a plurality of light projection delay times provided accordingly. The interference control unit 9 includes a set value storage unit (set value storage memory) 12 and a light projection delay time output unit 14. The set value storage memory 12 includes a storage unit 21 that stores a plurality of steps of interference light detection timing, a storage unit 22 that stores a plurality of steps of interference light detection level provided for each step of the interference light detection timing, and interference light. And a storage unit 23 for storing a plurality of projection delay times provided for each combination of detection timing and interference light detection level. These set values may be stored in advance or may be set by external input.

投光遅延時間出力部１４は、前記干渉光検知信号の干渉光検知タイミングにおける干渉光検知レベルが、前記記憶された干渉光検知タイミングにおける干渉光検知レベルの設定値以上に該当する場合に、これら各設定値の組合せに応じた投光遅延時間の設定値を投光制御部１０に出力する。   When the interference light detection level at the interference light detection timing of the interference light detection signal is equal to or greater than the set value of the interference light detection level at the stored interference light detection timing, the light projection delay time output unit 14 The setting value of the light projection delay time corresponding to the combination of the setting values is output to the light projection control unit 10.

前記投光制御部１０は、駆動回路２に対して物体検知タイミングまたは所定の投光遅延時間だけ遅延された物体検知タイミングで投光パルスを出力することにより、投光素子１を出力させるように駆動回路２を制御する。   The light projection control unit 10 outputs the light projection element 1 by outputting a light projection pulse to the drive circuit 2 at an object detection timing or an object detection timing delayed by a predetermined light projection delay time. The drive circuit 2 is controlled.

以下、上記構成の光電センサにおける干渉光防止動作を、図３、４に基づいて説明する。図３は設定値記憶メモリ１２に記憶された設定値の一例を示し、図４は投光遅延動作を表すタイムチャートを示す。   The interference light preventing operation in the photoelectric sensor having the above configuration will be described below with reference to FIGS. FIG. 3 shows an example of the set value stored in the set value storage memory 12, and FIG. 4 shows a time chart showing the light projection delay operation.

図３のように、干渉制御部９における設定値記憶メモリ１２には、物体検知タイミング終了前６クロック、４クロック、および２クロックの干渉光検知タイミングの各段階に対して、それぞれレベル２、１、３の３段階の干渉光検知レベルが記憶されている。各干渉光検知タイミングにおける各干渉光検知レベルの各段階に対して、３、４、５、６クロックの４つの投光遅延時間が記憶されている。つまり、干渉光検知タイミングと干渉光検知レベルの各段階による９つの組合せに対して４つの投光遅延時間が設けられている。物体検知タイミングの終了時点に近づけば近づく程に、干渉光の影響が大きくなるので、投光遅延時間も大きな値に設定している。   As shown in FIG. 3, the set value storage memory 12 in the interference control unit 9 stores levels 2, 1 and 6 for each stage of the interference light detection timing of 6 clocks, 4 clocks, and 2 clocks before the end of the object detection timing, respectively. 3, three levels of interference light detection levels are stored. For each stage of each interference light detection level at each interference light detection timing, four light projection delay times of 3, 4, 5, and 6 clocks are stored. That is, four light projection delay times are provided for nine combinations of each stage of the interference light detection timing and the interference light detection level. The closer to the end point of the object detection timing, the greater the influence of the interference light, so the light projection delay time is also set to a large value.

図３において、例えば、干渉光検知レベル１は、物体を検知するしきい値であるＯＮ検知レベル×０．８、干渉光検知レベル２は、ＯＮ検知レベル×０．４、干渉光検知レベル３は、干渉光の跳ね返り信号であり、オフセット電圧−（ＯＮ検知レベル×０．４）に設定される。なお、１クロックは所定値（例えば、５μｓ以下）に設定される。   In FIG. 3, for example, the interference light detection level 1 is an ON detection level × 0.8 which is a threshold value for detecting an object, the interference light detection level 2 is an ON detection level × 0.4, and an interference light detection level 3. Is a bounce signal of interference light, and is set to offset voltage− (ON detection level × 0.4). One clock is set to a predetermined value (for example, 5 μs or less).

カウンタ回路１１は、タイマとカウンタを有し、干渉光がない場合には例えば、タイマにより計時されて、カウンタにより２５クロックを１周期としてカウントされる。２５クロックごとに、物体検知タイミングが比較回路６に与えられる。２５クロックをカウントするとリセットされる。また、設定値記憶メモリ１２に記憶された各段階に基づいて、カウンタ回路１１により、物体検知タイミングの終了前における６、４、２クロックの干渉光検知タイミングが比較回路６に与えられ、この干渉光検知タイミングに対応して、各干渉光検知レベル１〜３が干渉光検知しきい値として比較回路６に与えられる。   The counter circuit 11 has a timer and a counter. When there is no interference light, for example, the counter circuit 11 is timed by a timer and counted by the counter with 25 clocks as one cycle. The object detection timing is given to the comparison circuit 6 every 25 clocks. It is reset when 25 clocks are counted. Further, based on each stage stored in the set value storage memory 12, the counter circuit 11 gives the 6, 4, and 2 clock interference light detection timings before the end of the object detection timing to the comparison circuit 6, and this interference. Corresponding to the light detection timing, the interference light detection levels 1 to 3 are given to the comparison circuit 6 as interference light detection threshold values.

図１の増幅回路５で増幅された受光信号について、比較回路６により、２５クロックごとの物体検知タイミングでＯＮ検知レベルをもつしきい値と比較されて物体Ｍの有無が検出される。物体検知タイミング終了前における６クロック、４クロック、２クロックの干渉光検知タイミングで各干渉光検知レベル１〜３をもつ干渉光検知しきい値と比較されて干渉光が検知される。   The light reception signal amplified by the amplifier circuit 5 in FIG. 1 is compared with a threshold value having an ON detection level at the object detection timing every 25 clocks by the comparison circuit 6 to detect the presence or absence of the object M. The interference light is detected by comparing with the interference light detection thresholds having the interference light detection levels 1 to 3 at the interference light detection timing of 6 clocks, 4 clocks, and 2 clocks before the end of the object detection timing.

図４のように、物体検知タイミング終了前６クロック〜４クロック間（図示ａ）の干渉光検知タイミングで干渉光検知レベル２の干渉光（図示ｂ）を検知した場合、３クロック（図示ｃ）の投光遅延時間がセットされる。この場合、前回の物体検知タイミングよりも３クロックだけ遅らせた物体検知タイミングで投光素子１から投光ビームが照射され、カウンタ回路１１は３クロック遅らせたうえで２５クロックをカウントする。   As shown in FIG. 4, when interference light (b) shown at interference light detection level 2 is detected at the interference light detection timing between 6 clocks and 4 clocks (shown a) before the end of the object detection timing, 3 clocks (shown c). Is set. In this case, a light projection beam is emitted from the light projecting element 1 at an object detection timing delayed by 3 clocks from the previous object detection timing, and the counter circuit 11 counts 25 clocks after being delayed by 3 clocks.

なお、仮に、その後、物体検知タイミング終了前２クロック〜０クロック間（図示ｄ）の干渉光検知タイミングで、図示しない干渉光検知レベル３の干渉光を検知した場合、前記投光遅延時間の３クロックをリセットして６クロック（図示ｅ）の投光遅延時間が再セットされる。そして、最終的にセットされた６クロックを投光遅延時間として、前回の物体検知タイミングよりも６クロックだけ遅らせた物体検知タイミングで投光素子１から投光ビームが照射され、カウンタ回路１１は６クロック遅らせたうえで２５クロックをカウントする。   If an interference light of interference light detection level 3 (not shown) is detected at an interference light detection timing between 2 clocks and 0 clocks (d in the drawing) before the end of the object detection timing, the light projection delay time 3 is assumed. The clock is reset and the light emission delay time of 6 clocks (e in the figure) is reset. Then, with the finally set 6 clocks as the light projection delay time, the light projection beam is emitted from the light projecting element 1 at the object detection timing delayed by 6 clocks from the previous object detection timing, and the counter circuit 11 has 6 After delaying the clock, 25 clocks are counted.

これにより、各光電センサの相互干渉が防止されるとともに、干渉光検知信号の複数段階の干渉光検知タイミングにおける干渉光検知レベル、つまり干渉光検知タイミングと干渉光検知レベルを細分化して検知して、干渉光の経時的な検知状態に応じた最適な遅延時間を与えることができる。   This prevents mutual interference of each photoelectric sensor, and detects the interference light detection level at the interference light detection timing in multiple stages of the interference light detection signal, that is, subdivides and detects the interference light detection timing and the interference light detection level. In addition, it is possible to provide an optimum delay time according to the detection state of interference light over time.

このように、本発明は、干渉制御部９において、物体検知タイミングの終了前での複数段階の干渉光検知タイミングにおける複数段階の干渉光検知レベルを設け、これに応じて複数段階の投光遅延時間を設けているので、従来のように複数段階の干渉光検知レベルおよび投光遅延時間だけを設けたのと異なり、これに複数段階の干渉光検知タイミングを加味して検知していることから、干渉光の経時的な検知状態に応じた最適な遅延時間を与えるので、無駄な遅延時間がなくなり、全体として可及的に投光遅延時間を短縮することができ、高速測定に対応可能となる。   Thus, according to the present invention, the interference control unit 9 provides a plurality of stages of interference light detection levels at a plurality of stages of interference light detection timing before the end of the object detection timing, and a plurality of stages of light projection delays accordingly. Because time is provided, unlike the conventional case where only multiple levels of interference light detection level and projection delay time are provided, it is detected by taking into account multiple levels of interference light detection timing. Since the optimum delay time according to the detection state of interference light over time is given, useless delay time is eliminated, and the light projection delay time can be shortened as much as possible as a whole, and high-speed measurement can be supported. Become.

本発明の一実施形態に係る干渉防止機能付き光電センサを示すブロック図である。It is a block diagram which shows the photoelectric sensor with an interference prevention function which concerns on one Embodiment of this invention. 図１の光電センサの干渉制御部を示すブロック図である。It is a block diagram which shows the interference control part of the photoelectric sensor of FIG. 設定値記憶部に記憶された設定値の一例を示す図である。It is a figure which shows an example of the setting value memorize | stored in the setting value memory | storage part. 投光遅延動作を表すタイムチャートである。It is a time chart showing a light projection delay operation.

符号の説明Explanation of symbols

１：投光素子（ＬＥＤ）
２：駆動回路
３：受光素子（ＰＤ）
５：増幅回路
６：比較回路（コンパレータ）
７：制御部（ＣＰＵ）
９：干渉制御部
１０：投光制御部
１２：設定値記憶部
１４：投光遅延時間出力部
２１：干渉光検知タイミング記憶部
２２：干渉光検知レベル記憶部
２３：投光遅延時間記憶部
Ｍ：検出物体 1: Projection element (LED)
2: Drive circuit 3: Light receiving element (PD)
5: Amplifier circuit 6: Comparison circuit (comparator)
7: Control unit (CPU)
9: Interference control unit 10: Projection control unit 12: Set value storage unit 14: Projection delay time output unit 21: Interference light detection timing storage unit 22: Interference light detection level storage unit 23: Projection delay time storage unit M : Detection object

Claims (2)

投光素子を出力させて投光ビームを照射させる駆動回路と、投光ビームで照射された物体からの反射光を受光した受光素子からの受光信号を増幅する増幅回路と、投光素子の出力を開始させる物体検知タイミングで、増幅された受光信号の電圧と所定しきい値との比較に基づき、物体検知信号を出力する比較回路とを備えた光電センサであって、
前記比較回路は、さらに前記物体検知タイミングの終了前に複数段階設けられた干渉光検知タイミングで、増幅された受光信号の電圧と、前記干渉光検知タイミングごとに複数段階設けられた干渉光検知レベルをもつ干渉光検知しきい値との比較に基づき干渉光検知信号を出力するものであり、
前記干渉光検知信号の干渉光検知タイミングにおける干渉光検知レベルに基づき、これに応じて複数設けられた投光遅延時間から所定の投光遅延時間を出力する干渉制御部と、
前記所定の投光遅延時間だけ遅延された物体検知タイミングで前記投光素子を出力させるように前記駆動回路を制御する投光制御部と、
を備えている干渉防止機能付き光電センサ。 A drive circuit that outputs a light projecting element to emit a light projecting beam, an amplifier circuit that amplifies a light reception signal from a light receiving element that receives reflected light from an object irradiated with the light projecting beam, and an output of the light projecting element A photoelectric sensor comprising a comparison circuit that outputs an object detection signal based on a comparison between the voltage of the amplified light reception signal and a predetermined threshold at an object detection timing for starting
The comparison circuit further includes a voltage of the received light signal amplified at a plurality of stages of interference light detection timing provided before the end of the object detection timing, and an interference light detection level provided at a plurality of stages for each interference light detection timing. The interference light detection signal is output based on the comparison with the interference light detection threshold having
Based on the interference light detection level at the interference light detection timing of the interference light detection signal, an interference control unit that outputs a predetermined light projection delay time from a plurality of light projection delay times provided in response thereto,
A light projecting control unit for controlling the drive circuit to output the light projecting element at an object detection timing delayed by the predetermined light projecting delay time;
Photoelectric sensor with interference prevention function. 請求項１において、前記干渉制御部は、
前記干渉光検知タイミングの複数段階と、干渉光検知タイミングの各段階ごとに設けられた干渉光検知レベルの複数段階と、干渉光検知タイミングおよび干渉光検知レベルの各段階の組合せごとに設けられた複数の投光遅延時間とを記憶する設定値記憶部と、
前記干渉光検知信号の干渉光検知タイミングにおける干渉光検知レベルが、前記記憶された干渉光検知タイミングにおける干渉光検知レベルの各段階に該当する場合に、これら各段階の組合せに応じた所定の投光遅延時間を前記投光制御部に出力する遅延時間出力部と、
を備えている干渉防止機能付き光電センサ。 The interference control unit according to claim 1,
Provided for each combination of multiple stages of the interference light detection timing, multiple stages of interference light detection level provided for each stage of interference light detection timing, and each stage of interference light detection timing and interference light detection level A set value storage unit for storing a plurality of light projection delay times;
When the interference light detection level at the interference light detection timing of the interference light detection signal corresponds to each stage of the interference light detection level at the stored interference light detection timing, a predetermined projection corresponding to the combination of these stages is performed. A delay time output unit for outputting an optical delay time to the light projection control unit;
Photoelectric sensor with interference prevention function.
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CN113567781A (en) * 2021-07-17 2021-10-29 深圳市志奋领科技有限公司 Anti-interference method and system for photoelectric sensor

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Publication number Priority date Publication date Assignee Title
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