JPH06281746A - System for detecting object - Google Patents

Abstract

PURPOSE:To provide an object detecting system which scarcely affects other object detectors even if any object detector fails when linking a plurality of object detectors. CONSTITUTION:Synchronous oscillation circuits prescribing the generation timing of the ultrasonic waves of each object detector for a plurality of object detectors are connected by a synchronous line Ls. Each object detector transmits a stop signal to the synchronous line Ls while it receives reflection waves and then stops the transmission of a next ultrasonic wave until the stop signal is canceled in all object detectors. Each object detector is provided with a stop time monitoring circuit 4 for monitoring the continuation time of the stop time and then turns off a switch circuit 5 judging that a failure has occurred when the continuation time of the stop signal exceeds a certain time. The switch circuit 5 is inserted in the connection part with the synchronous line Ls and then prohibits the transmission of the stop signal to other object detectors when the switch circuit 5 is turned off.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is provided with a plurality of object detectors for detecting the presence or absence of an object in a surveillance space by using a detection wave such as an ultrasonic wave. The present invention relates to an object detection system in which the respective object detectors are synchronized with each other so that transmission of the next detection wave from each object detector is stopped until the object detection is stopped.

[0002]

2. Description of the Related Art An object detector having a structure shown in FIG. 8 has been conventionally known. This object detector is configured to intermittently transmit an ultrasonic wave as a detection wave to the monitoring space and to judge that an object exists in the monitoring space when receiving a reflected wave within a predetermined period after the transmission. Has been done. That is, the object detector is
A wave transmitter / receiver 1 which is also used for transmitting / receiving ultrasonic waves to / from a monitoring space is provided. The wave transmission signal input to the wave transmitter / receiver 1 is generated based on the wave transmission timing signal generated by inputting the trigger pulse of a constant cycle (for example, 70 msec) output from the cycle oscillating circuit 2 to the gate creating circuit 3. To be done. The transmission timing signal is input to the transmission pulse generation circuit 11 to output a pulse signal having a constant pulse width, and the ultrasonic oscillation circuit 12
Then, the transmission signal having the frequency of the ultrasonic wave transmitted from the wave transmitter / receiver 1 is output during the ON period of the pulse signal output from the transmission pulse generation circuit 11. The ultrasonic oscillation circuit 12 is synchronized with the pulse signal output from the transmission pulse generation circuit 11.
The transmission signal that is intermittently output from is amplified by the transmission amplification circuit 13 and then input to the wave transmitter / receiver 1, becomes an ultrasonic wave, and is intermittently transmitted to the monitoring space. As described above, the wave transmitter / receiver 1, the periodic oscillating circuit 2, the gate creating circuit 3, the wave sending pulse creating circuit 11, the ultrasonic wave oscillating circuit 12, and the wave sending pulse creating circuit 13 constitute a wave sending means.

On the other hand, when an ultrasonic wave from the monitoring space such as a reflected wave by an object in the monitoring space is received by the transmitter / receiver 1 and a received signal is output from the transmitter / receiver 1, the received signal is received. After being amplified by the wave amplifier circuit 21, it is input to the detection / waveform shaping circuit 22 to perform detection and waveform shaping. By the way, the gate creation circuit 3 generates a reception timing signal in order to set a predetermined period after the transmission as a detection gate period in synchronism with the timing of transmitting the ultrasonic wave, and the reception timing signal is the detection timing signal. A gate signal that is input to the circuit 23 and becomes H level during a period corresponding to the detection gate period is generated. The gate signal from the detection gate circuit 23 is input to the AND circuit 24 together with the output of the detection / waveform shaping circuit 22, and when the output of the detection / waveform shaping circuit 22 becomes H level during the detection gate period, the detection / waveform shaping circuit 22 is detected. The output of is passed. In short, if the reflected wave is received within a predetermined period after the ultrasonic wave is transmitted, it is determined that there is an object that has reflected the ultrasonic wave in the specified monitoring space, and the signal corresponding to this reflected wave is logically determined. It is extracted by the product circuit 24.

The output of the AND circuit 24 is input to the set terminal S of the RS flip-flop 25,
A pulse signal from the transmitted pulse generation circuit 11 is input to the reset terminal R of the RS flip-flop 25. That is, the RS flip-flop 25 is reset by the rising of the output of the transmitted pulse generation circuit 11 to set the output to the L level, and when the signal corresponding to the reflected wave passes through the AND circuit 24, the output is set to the H level. To Therefore, the presence or absence of a reflected wave within the detection gate period is detected for each ultrasonic wave transmission, and if there is a reflected wave, the output of the RS flip-flop 25 becomes H during the period until the next ultrasonic wave transmission.
It becomes a level. When the output of the RS flip-flop 25 becomes H level, an output signal is produced by the output circuit 26 and the relay 27 is driven. If an alarm device or the like is driven by the relay 27, the object detector can be used for monitoring the presence or absence of an empty space in the parking lot. Here, the transmitter / receiver 1, the periodic oscillation circuit 2,
Gate creation circuit 3, reception amplification circuit 21, detection / waveform shaping circuit 22, detection gate circuit 23, AND circuit 24, R-
The S flip-flop 25, the output circuit 26, and the relay 27 constitute wave receiving means.

By the way, it is known that when the temperature is low, the attenuation of ultrasonic waves is reduced, so that multiple reflection is likely to occur between the object and the transducer 1. When an ultrasonic wave is transmitted at a constant cycle under such a condition that a reflected wave accompanied by such multiple reflection is input to the transducer 1, the reflected wave caused by the multiple reflection generated by the previous transmission of the ultrasonic wave is detected. A phenomenon may occur in which waves are received during the gate period, in which case erroneous detection occurs even though there is no object in the surveillance space.

In order to prevent such erroneous detection, it is conceivable to set the ultrasonic wave generation period to be long so that the ultrasonic wave is not transmitted during the period in which a reflected wave due to multiple reflection occurs. Depending on the settings of the surveillance space,
The effect of multiple reflection can be eliminated by setting the transmission interval to, for example, 20 msec or more. However, if the transmission interval is set to be long, the average time from when the object is present in the monitoring space of the object detector until the object is actually detected becomes long, which causes a problem that the response is deteriorated.

In the object detector shown in FIG. 8, the output of the detection / waveform shaping circuit 22 is equivalent to the reflected wave due to the multiple reflections, as a structure for avoiding the influence of the multiple reflections while preventing such a problem. The configuration is such that the periodic oscillation circuit 2 is controlled so as not to generate a trigger pulse during the period in which the output is obtained. The operation of this configuration will be described with reference to FIG. Here, S ₁ to
S ₈ indicates the signal of the corresponding portion in FIG. Period oscillation circuit 2
9A, a trigger pulse as shown in FIG. 9A is generated, and the transmission pulse generation circuit 11 generates a pulse signal as shown in FIG. 9B. The output of the detection gate circuit 23 is shown in FIG.
As in (c), it becomes H level during the detection gate period. Now, assuming that the wave transmitter / receiver 1 receives a reflected wave due to multiple reflection as shown in FIG. 9 (d), the output of the detection / waveform shaping circuit 22 becomes as shown in FIG. 9 (e). Since the output of the detection / waveform shaping circuit 22 corresponding to the object existing in the space passes through the AND circuit 24 during the detection gate period as shown in FIG. 9F, the RS flip-flop as shown in FIG. 25 operates to output the output circuit 26 as shown in FIG.
Keeps the output at the H level. Here, during the period in which the reflected wave due to the multiple reflection is received, the detection / waveform shaping circuit 22
Since the output of the signal becomes H level at a relatively short time interval, this signal resets the transmission control means provided in the periodic oscillation circuit 2 to stop the generation of the trigger pulse from the periodic oscillation circuit 2. Since the next transmission is not performed, it is possible to prevent erroneous detection. Further, if there is a signal that passes through the AND circuit 24 during the detection gate period for each ultrasonic wave transmission, the output of the output circuit 26 is maintained at the H level.

On the other hand, when an abnormality occurs in the receiving / amplifying circuit 21 and becomes an oscillating state, the operation is as shown in FIG.
That is, in the oscillation state of the reception amplification circuit 21,
The output is continuously obtained as in the right half of (d), and the output of the detection / waveform shaping circuit 22 is continuously at the H level. Therefore, the transmission control means provided in the periodic oscillator circuit 2 can be kept in the reset state and the generation of the trigger pulse from the periodic oscillator circuit 2 can be stopped. FIG. 10 shows a state in which an object is detected when the first ultrasonic wave is transmitted, but since an object is not detected in the next ultrasonic wave, the RS flip-flop is transmitted when the second ultrasonic wave is transmitted. 25 is reset, and the output of the output circuit 26 is also set to L level. Here, the output of the output circuit 26 is L
The output is set to the L level after a predetermined delay time has elapsed after reaching the level, and the delay time is set to about the time from the transmission of ultrasonic waves to the end of the detection gate period. 9 and 10, the signal generated at the output of the receiving and amplifying circuit 21 at almost the same time as the ultrasonic wave transmission is
This is due to the sneak of the detected wave from the wave transmitting means to the wave receiving means and the reverberation of the wave transmitter / receiver 1.

The transmission control means in the periodic oscillator circuit 2 will be described more specifically. That is, as shown in FIG. 11, the transmission control means has a series circuit of a resistor R ₁ and a capacitor C ₁ inserted between both ends of a power source, and an emitter-collector connected between both ends of the capacitor C ₁ . A transistor Q ₁ as a switch element and a NOT circuit NT for generating a binary output according to the terminal voltage of the capacitor C _1.
1, a diode D ₁ of the back-flow inhibiting provided at the output of the NOT circuit NT _1, a gate circuit which outputs the NOT circuit NT ₁ is formed of a NOR circuit for stopping the oscillating operation of the periodic oscillation circuit 2 when it is H level G ₁ and. Transistor Q ₁
The base, there is the output of detection and waveform shaping circuit 22 is input, since the output of the detection and the waveform shaping circuit 22 the transistor Q ₁ is turned on during a period at the H level, the capacitor C ₁ Is not charged, and the stop signal which is the output of the NOT circuit NT ₁ is always at the H level. At this time,
The gate circuit G ₁ stops the generation of the trigger pulse from the periodic oscillator circuit 2. On the other hand, while the output of the detection / waveform shaping circuit 22 is at the L level, the transistor Q ₁ is off and the terminal voltage of the capacitor C ₁ has a time constant determined by the resistor R ₁ and the capacitor C _1. elevated, cyclic output NOT circuit denied exceeds the threshold input of NT ₁ circuit NT ₁ is released the stop signal becomes L level oscillation circuit 2
The trigger pulse from can be generated.

By the way, in order to detect the presence / absence of a vacant space in a parking lot using an object detector, it is necessary to provide an object detector for each parking space and link a plurality of object detectors. . Therefore, as shown in FIG. 11, it is conceivable to connect the transmission control means of the object detector to each other via the synchronization line Ls. That is, the output of the diode D ₁ provided in each object detector is connected not only to the gate switch G ₁ but also to the synchronizing terminal Ts, and the synchronizing line Ls is connected to the synchronizing terminal Ts.
With such a configuration, in any of the object detectors,
When the generation of the trigger pulse has stopped the output of the NOT circuit NT ₁ have been receives a reflected wave due to multiple reflections from periodic oscillation circuit 2 becomes H level, the other objects detector NOT circuit NT ₁ Even if the output is L level, the gate circuit G
The input of ₁ becomes H level, and the operation of the periodic oscillation circuit 2 is stopped. That is, even if a plurality of object detectors are interlocked by stopping the transmission of the next ultrasonic wave until all the object detectors connected via the synchronization line Ls do not receive the reflected wave due to the multiple reflection. It prevents false positives.

The operation in the configuration of FIG. 11 is as shown in FIG. Here, S _{11 to} S ₁₄ , S _{21 to} S ₂₄ in FIG.
S ₃₁ to S ₃₄ is shown a signal corresponding part of Figure 11.
However, S ₁₁ , S ₂₁ , and S ₃₁ correspond to the corresponding receiving and amplifying circuit 21.
Shows the output of. As is clear from FIG. 12, the upper two object detectors cannot detect the reflected wave due to the multiple reflection prior to the lower one object detector, and FIG.
As shown in (g), the stop signal from the negation circuit NT ₁ is released first and becomes the L level, which is in the standby state. Here, when a reflected wave due to multiple reflections is no longer detected by one of the object detectors below and the stop signal is released as shown in FIG. 12 (k), the stop signals are released in all the object detectors. Therefore, at this point, the periodic oscillator circuits 2 of all the object detectors can oscillate.

[0012]

By the way, in the above-described object detection system, when the receiving and amplifying circuit 21 oscillates in any of the object detectors, a stop signal is continuously generated from the object detector. . When a stop signal is continuously generated in this way, in addition to the ultrasonic wave not being transmitted from the object detector and the detection operation stops, the detection operation also stops for other object detectors. After all, there is a problem that the detection operation stops in the entire object detection system. Moreover, even in a small-scale system in which the number of object detectors constituting the object detection system is relatively small, the failure location can be easily found, but a large number of object detectors are used in a large-scale parking lot. In this case, it is difficult to find out which object detector has an abnormality, and it takes time to restore the object detection system.

An object of the present invention is to solve the above problems. When a plurality of object detectors are linked, even if an abnormality occurs in one of the object detectors, another object is detected. The object of the present invention is to provide an object detection system that causes almost no influence on the vessel.

[0014]

In order to achieve the above-mentioned object, the invention of claim 1 comprises: a transmitting means for transmitting a detection wave intermittently; and a predetermined period after the detection wave is transmitted. Receiving means that determines the presence or absence of an object in the specified monitoring space according to the presence or absence of the reflected wave, and stops during the period when the receiving input is detected almost continuously after the detection wave is transmitted. A transmission control means that generates a signal to forcibly stop the transmission of the detection wave by the transmission means and releases the stop signal when the receiving input is stopped, and the transmission wave during the period when the stop signal is input from the outside. A plurality of object detectors each having a synchronizing means for forcibly stopping the transmission of the detection wave by the means, and the stop signals output from the transmission control means of each object detector are all other object detectors. Connect the object detectors to each other via a sync line so that they can be input to In Te object detection system transmitting control means of the object detector to stop transmitting the detection waves all objects detector until the time of detecting the stop of the reception input,
Each of the object detectors is characterized by including an abnormality detecting means for generating an abnormal signal when detecting an abnormality in its operation, and a separating means for disconnecting the synchronizing means from the synchronizing line when the abnormal signal occurs.

According to a second aspect of the present invention, the abnormality detecting means is a power supply voltage monitoring circuit for monitoring the power supply voltage of each object detector, and generates an abnormal signal when the power supply voltage is out of the specified range. To do. According to a third aspect of the invention, the abnormality detecting means is a transmission level monitoring circuit for monitoring the output level of the detection wave, and generates an abnormality signal when the output level of the detection wave is out of the specified range. .

According to a fourth aspect of the present invention, the abnormality detecting means is a wave-receiving level monitoring circuit for monitoring the level of the detected wave that has sneak into the wave-receiving means when the detection wave is being transmitted. An abnormal signal is generated when the level of the detected wave is out of the specified range. According to a fifth aspect of the present invention, the detected wave is an ultrasonic wave, and the abnormality detection means is a reverberation time monitoring circuit for monitoring the duration of the reverberation input to the receiving means immediately after the detection wave is transmitted. An abnormal signal is generated when the duration is longer than a specified value.

The invention of claim 6 is characterized in that the separating means is selected from any one of a relay, a switching transistor and an analog switch. The invention of claim 7 is characterized in that display means for displaying the presence or absence of an abnormal signal from the abnormality detecting means is added. The invention of claim 8 is
It is characterized in that a transfer terminal for outputting an abnormality signal from the abnormality detecting means to the outside is added.

[0018]

According to the invention of claim 1, an abnormality detecting means for generating an abnormality signal when each of the object detectors detects an abnormality in its operation, and a separating means for disconnecting the synchronizing means from the synchronizing line when the abnormality signal occurs. By providing multiple object detectors with each other via a sync line, if an abnormality occurs in one of the object detectors, the object detector with the abnormality is separated. By the means, the operation is removed from the synchronization line, and as a result, the operation of the other object detector having no abnormality is not stopped.

The inventions of claims 2 to 5 are preferred embodiments of the abnormality detecting means. According to the second aspect of the present invention, the power supply voltage monitoring circuit that monitors the power supply voltage of each object detector is used as the abnormality detection means, and an abnormal signal is generated when the power supply voltage is out of the specified range. According to the third aspect of the present invention, the transmission level monitoring circuit that monitors the output level of the detection wave is used as the abnormality detection means, and the abnormality signal is generated when the output level of the detection wave is out of the specified range. According to the invention of claim 4, the received wave level monitoring circuit for monitoring the level of the detected wave sneaking into the wave receiving means is used as the abnormality detecting means, and an abnormal signal is generated when the received wave level is outside the specified range. The invention of claim 5 is a preferred embodiment when the detected wave is an ultrasonic wave, and an abnormality is detected in the reverberation time monitoring circuit for monitoring the duration of the reverberation input to the wave receiving means immediately after the transmission of the ultrasonic wave. It is used as a means, and an abnormal signal is generated when the duration of reverberation is longer than a specified value.

The invention of claim 6 is a preferred embodiment of the separating means, wherein any one of a relay, a switching transistor and an analog switch is used as the separating means. According to the invention of claim 7, by adding the display means for displaying the presence or absence of the abnormal signal from the abnormality detection means, when the display state of the display means is seen, the separation means disconnects from the synchronization line. It is possible to easily find an object detector that has failed, and it is easy to restore the object detector in which an abnormality has occurred.

According to the eighth aspect of the present invention, by adding the transfer terminal for outputting the abnormal signal from the abnormality detecting means to the outside, the monitoring device or the like provided with the output from the transfer terminal separately. It is possible to monitor, and for example, if a monitoring board that collectively monitors an abnormal signal at one place is used, it becomes easy to manage the presence or absence of an abnormality.

[0022]

【Example】

(Embodiment 1) The basic construction of this embodiment is the same as the conventional construction shown in FIGS. 8 and 11, and therefore the differences will be mainly described. As shown in FIG. 1, in the present embodiment, the stop time monitoring circuit 4 for monitoring the duration of the stop signal output from the NOT circuit NT ₁ in the wave transmission control means provided in the periodic oscillation circuit 2 is used as the abnormality detecting means. I have it. Further, the connection point between the diode D ₁ and the gate circuit G ₁ and the synchronization terminal Ts
A switch circuit 5 using any one of a relay, a transistor, and an analog switch as a separating means is inserted between and, and the opening / closing of the switch circuit 5 is controlled by the output of the stop time monitoring circuit 4. When the duration of the stop signal exceeds a certain time, the stop time monitoring circuit 4 determines that there is an abnormality such as the receiving amplifier circuit 21 being in an oscillating state and controls the switch circuit 5 to be off. ,
Under other conditions, the switch circuit 5 is controlled to be turned on.
Other configurations are the same as the conventional configurations shown in FIGS.

Next, the operation of the above configuration will be described with reference to FIG. Here, S _{11 to} S ₁₅ in FIG.
S _23, S ₂₄ indicates the signal of the corresponding portions of FIG. 1, S _21, S ₂₂ in FIG. 2, the S _11, S ₁₂ of the upper-frequency oscillator circuit 2 in the middle of the cycle oscillation circuit 2 in FIG. 1 The signals at the corresponding points are shown. However, S ₁₁ and S ₂₁ are shown by the output of the corresponding receiving and amplifying circuit 21. Now, assuming that the receiving amplifier circuit 21 oscillates in the object detector including the periodic oscillator circuit 2 in the upper part of FIG. 1, the output of the receiving amplifier circuit 21 is as shown in FIG.
As shown in FIG. 2A, as a result, the terminal voltage of the capacitor C ₁ does not rise as shown in FIG. 2B, and the output of the negation circuit NT ₁ as shown in FIG. At some point, it will be kept at H level from the time of rising. Since the ultrasonic wave transmission is stopped during the period when the output of the NOT circuit NT ₁ is at H level, the stop time monitoring circuit 4 measures this stop time and is defined as shown in FIG. 2 (e). When a certain time tx has elapsed, the output of the stop time monitoring circuit 4 rises and the switch circuit 5 turns off. At this point, the periodic oscillator circuit 2 is disconnected from the synchronization line Ls.

On the other hand, since the object detector including the interrupted periodic oscillating circuit 2 is operating normally, an output as shown in FIG. 2 (f) is generated from the receiving and amplifying circuit 21, and the voltage across the capacitor C ₁ is generated. Changes as shown in FIG. Here, in a period in which the output of the upper NOT circuit NT ₁ is at the H level,
While the switch circuit 5 is on, the period oscillation circuit 2 in the middle stage also stops operating as described in the related art. However, as described above, the operation of the stop time monitoring circuit 5 causes the switch circuit 5 to operate. When is turned off, the input from the synchronization line Ls becomes L level as shown in FIG. 2 (i), and at this time, ultrasonic waves can be transmitted. In short, when the switch circuit 5 of the object detector in which the abnormality has occurred is turned off, the object detector is disconnected from the synchronization line Ls, and as a result, ultrasonic waves can be transmitted by other object detectors. It will be. In this way, even if an abnormality occurs in any of the object detectors, the operation of the other object detectors becomes possible again after the elapse of the fixed time tx, and the abnormality of one object detector is caused. It has almost no effect on other object detectors.

(Embodiment 2) In this embodiment, as shown in FIG. 3, a power supply voltage monitoring circuit 4a is provided as an abnormality detecting means. That is, the power supply voltage is stabilized inside each object detector by the constant voltage power supply circuit 6, and is supplied to the constant voltage power supply circuit 6 through the power supply line Lp connected to the power supply terminal Tp. The power supply voltage monitoring circuit 4a monitors the output voltage of the constant voltage power supply circuit 6, and when the output voltage of the constant voltage power supply circuit 6 drops due to a short circuit due to deterioration of components or a leakage current due to intrusion of rainwater. , Generates an abnormal signal and turns off the switch circuit 5. The output of the relay 27 is connected to an external circuit through the output terminal To. The other configuration is the same as that of the first embodiment, and the operation after the abnormal signal is generated from the power supply voltage monitoring circuit 4a is the same as that of the first embodiment. Further, in this embodiment, the abnormal signal is generated when the power supply voltage drops, but the abnormal signal may be generated when the power supply voltage rises.

(Embodiment 3) In this embodiment, as shown in FIG. 4, a transmission level detection circuit 4b for detecting the peak value of the output voltage of the transmission amplification circuit 13 is provided as an abnormality detecting means. The voltage applied to the transducer 1 is, for example, 6 when normal.
Although it becomes 0 V _PP , the voltage applied to the wave transmitter / receiver 1 is lowered when the wave transmitter / receiver 1 is defective or an abnormality occurs in the circuit of the wave transmitting means. Therefore, in the wave transmission level detection circuit 4b, when the voltage applied to the wave transmitter / receiver 1 becomes equal to or lower than the specified voltage, an abnormal signal is generated to turn off the switch circuit 5.
The other configuration is the same as that of the first embodiment, and the operation after the abnormal signal is generated from the transmission level detection circuit 4b is also the same as that of the first embodiment. Here, in the transmission level detection circuit 4b, the abnormal signal is generated only when the applied voltage to the transducer 1 is decreased, but the abnormal signal may be generated when the applied voltage is increased.

Further, the presence or absence of abnormality may be determined based on the output level of the reception amplification circuit 21 instead of the output level of the transmission amplification circuit 13. In this case, the level of the reflected wave changes depending on the distance to the object, the sound absorption coefficient of the object, and the like. The output of the wave reception amplification circuit 21 at this time can be treated in the same manner as the output of the wave transmission amplification circuit 13.

(Embodiment 4) In this embodiment, as shown in FIG. 5, a reverberation time monitoring circuit 4 for monitoring the duration of the reverberation of the transducer 1 immediately after the transmission of ultrasonic waves as abnormality detecting means.
c is provided. If the duration of the ultrasonic wave at the time of transmission is 1 msec, the signal input to the receiving and amplifying circuit 21 along with the transmission of the ultrasonic wave will have a reverberation of, for example, 3 m.
It becomes sec. It is known that an increase in reverberation time is the most frequent phenomenon when an abnormality occurs in the transceiver 1. If the reverberation time becomes long, a signal due to reverberation may be input during the detection gate period, which causes malfunction. Therefore, in the reverberation time monitoring circuit 4c, if the reverberation time associated with the transmission of ultrasonic waves is longer than the specified value, it is regarded as abnormal and an abnormal signal is generated to turn off the switch circuit 5. The other configuration is the same as that of the first embodiment, and the operation after the abnormal signal is generated from the reverberation time monitoring circuit 4c is also the same as that of the first embodiment.

(Embodiment 5) In this embodiment, as shown in FIG. 6, in addition to the structure of Embodiment 4, a display 7 for leaving the generation of an abnormal signal is added. If the object detector is equipped with a power-on indicator that indicates the power supply to the power source or a detection indicator that indicates the detection of an object, these indicators can be displayed by blinking when an abnormal signal occurs. It may be replaced with the container 7. Further, instead of providing the display 7, the notification may be made by acoustic means. The display device 7 in the present embodiment is not applied only to the configuration of the fourth embodiment,
It is also applicable to other embodiments.

If such an indicator 7 is provided, even if a large number of object detectors are provided, it is possible to easily find the object detector in which an abnormality has occurred and the recovery work can be performed. It will be easier. (Embodiment 6) In this embodiment, as shown in FIG. 7, a transfer terminal Tt for extracting an abnormal signal to an external circuit is added to the structure of the embodiment 4. If the transfer terminal Tt is used to connect to a monitoring board or the like and an abnormal signal can be collectively managed by the monitoring board or the like, it is easy to find an object detector in which an abnormality has occurred. Further, as shown by the broken line in FIG. 7, the relay 27 is controlled by the abnormal signal,
If the relay 27 is intermittently turned on when an abnormal signal occurs, it is possible to know the object detector in which an abnormality has occurred due to a change in the operating state of an alarm connected to the relay 27. . The display 7 in this embodiment is
The present invention is not limited to the configuration of the fourth embodiment, but can be applied to other embodiments.

In each of the above embodiments, the ultrasonic wave is illustrated as the detection wave, but the detection wave is not necessarily limited to the ultrasonic wave, and the technical idea of the present invention is applicable even when using a microwave or light. Can be applied.

[0032]

As described above, according to the present invention, the abnormality detecting means for generating an abnormal signal when each of the object detectors detects an abnormal operation and the separating means for disconnecting the synchronizing means from the synchronizing line when the abnormal signal occurs. Since, when multiple object detectors are connected to each other via a sync line, if one of the object detectors has an abnormality, the object detector with the abnormality is separated. There is an advantage in that the operation of other object detectors which are not anomalous as a result of being removed from the synchronization line by the means is not stopped.

With the addition of display means for displaying the presence or absence of an abnormal signal from the abnormality detection means, the object detector separated from the synchronizing line by the operation of the separation means can be easily found by observing the display state of the display means. Therefore, there is an effect that it is easy to restore the object detector in which the abnormality has occurred. In the case where a transfer terminal for outputting an abnormal signal from the abnormality detecting means to the outside is added, the output from the transfer terminal can be monitored by a separately provided monitoring device or the like. The use of a monitoring panel that monitors the location has the advantage of facilitating the management of abnormalities.

[Brief description of drawings]

FIG. 1 is a circuit diagram of a main part of a first embodiment.

FIG. 2 is an operation explanatory diagram of the first embodiment.

FIG. 3 is a block diagram of a second embodiment.

FIG. 4 is a block diagram of a third embodiment.

FIG. 5 is a block diagram of a fourth embodiment.

FIG. 6 is a block diagram of a fifth embodiment.

FIG. 7 is a block diagram of a sixth embodiment.

FIG. 8 is a block diagram showing a conventional object detector.

FIG. 9 is an operation explanatory view of a conventional object detector.

FIG. 10 is an operation explanatory view of a conventional object detector.

FIG. 11 is a main part circuit diagram showing a conventional example.

FIG. 12 is an operation explanatory diagram of a conventional example.

[Explanation of symbols]

1 Transducer 2 Periodic oscillator circuit 3 Gate creation circuit 4 Stop time monitoring circuit 4a Power supply voltage monitoring circuit 4b Transmission level monitoring circuit 4c Reverberation time monitoring circuit 5 Switch circuit 6 Constant voltage power supply circuit 7 Indicator 11 Transmission pulse creation circuit 12 ultrasonic oscillation circuit 13 wave amplification circuit 21 wave reception amplification circuit 22 detection / waveform shaping circuit 23 detection gate circuit 24 AND circuit 25 RS flip-flop 26 output circuit 27 relay C ₁ capacitor D ₁ diode G ₁ gate circuit Ls sync line NT ₁ inversion circuit Q ₁ transistor R ₁ resistance Tt transfer terminal

Claims (8)

[Claims] 1. A wave transmission means for intermittently transmitting a detection wave,
Receiving means that determines the presence or absence of an object in the specified monitoring space according to the presence or absence of the reflected wave within a predetermined period after the detection wave is transmitted, and almost continuously after the detection wave is transmitted. A transmission control unit that generates a stop signal during the period when the reception input is detected to forcibly stop the transmission of the detection wave by the transmission unit and releases the stop signal when the reception input stops From the transmission control means of each object detector, equipped with a plurality of object detectors equipped with a synchronization means for forcibly stopping the transmission of the detection wave by the transmission means during the period when the stop signal is input from The object detectors are connected to each other via a synchronization line so that the stop signal can be input to the synchronizing means of all other object detectors, and the transmission control means of all object detectors receive the waves. Stop sending detection waves from all object detectors until the stop of In the body detection system, each object detector is provided with an abnormality detection unit that generates an abnormality signal when detecting an abnormality in each operation, and a separation unit that disconnects the synchronization unit from the synchronization line when the abnormality signal occurs. Object detection system. 2. The abnormality detection means is a power supply voltage monitoring circuit for monitoring the power supply voltage of each object detector, and generates an abnormality signal when the power supply voltage is out of a specified range. Object detection system. 3. The abnormality detecting means is a transmission level monitoring circuit for monitoring the output level of the detection wave, and generates an abnormality signal when the output level of the detection wave is out of a specified range. 1. The object detection system according to 1. 4. The abnormality detection means is a wave reception level monitoring circuit for monitoring the level of the detection wave that has sneak into the wave reception means when the detection wave is transmitted, and the level of the detection wave that has spilled into the wave reception means is The object detection system according to claim 1, wherein an abnormal signal is generated when the value is out of the specified range. 5. The detection wave is an ultrasonic wave, and the abnormality detection means is a reverberation time monitoring circuit for monitoring the duration of reverberation that is input to the wave receiving means immediately after the detection wave is transmitted. The object detection system according to claim 1, wherein an abnormal signal is generated when is longer than a specified value. 6. The object detection system according to claim 1, wherein the separating means is selected from any one of a relay, a switching transistor, and an analog switch. 7. The object detection system according to claim 1, further comprising display means for displaying the presence or absence of an abnormal signal from the abnormality detection means. 8. The object detection system according to claim 1, further comprising a transfer terminal for outputting an abnormality signal from the abnormality detection means to the outside.