JP4092377B2 - Security sensor - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a security sensor that detects illegal intruders, and can also detect a disturbing action that is performed so that the security sensor does not operate.
[0002]
[Prior art]
The security sensor outputs an alarm when an object such as an illegal intruder appears in the detection area. As a detection element for detecting an object, there are an element that detects an object from a temperature difference from the surroundings, and an element that detects a moving object using a Doppler effect. The security sensor is generally composed of an attachment base and a sensor main body so that the security sensor can be easily attached to a corresponding place. The attachment base is attached to a ceiling, a wall, a pillar, or the like, and the sensor body is supported by the attachment base. On the mounting base side, wiring to the power supply and a control panel, etc. that is installed in a suitable place where it is easy to operate is provided. The wiring of the sensor body and the wiring of the sensor body are the same as the mounting to the mounting base of the sensor body. It is configured to be connected at the same time.
[0003]
This security sensor does not operate during daytime when many people go in and out (during non-warning). At this time, remove the sensor body from the mounting base and prevent the sensor unit from detecting it. May be. If the detection element detects infrared rays, remove the sensor body, apply a coating that does not transmit infrared rays to the infrared incident path, or apply masking such as pasting paper tape or plastic tape, If the sensor body is mounted on the mounting base, it is difficult to detect from the outside that such a disturbing action has been performed. However, if you miss such an obstruction, you will not be able to detect it even if it is illegally invaded at night (at the time of warning), and criminal acts will be carried out easily. It is preferable that a function for detecting that an obstructing action is performed is provided.
[0004]
One such function is called a tamper function. This tamper function is to detect that the sensor body has been removed from the mounting base, and is a function to confirm that the 24-hour sensor (detection element) is always electrically connected.
In order to demonstrate this function, a loop for 24 hour alarm disconnection detection is created and connected to the alarm loop separately from the alarm loop that performs normal operation (detection of illegal intruders). Need to detect.
[0005]
[Problems to be solved by the invention]
However, in the security sensor having the tampering function as described above, between the control panel and the mounting base, wiring for supplying power to the sensor body and for transmitting a human body detection signal transmitted when the sensor body detects a human body. Wiring and wiring for detecting obstructions are necessary, and there are problems that the number of wirings is large and the mounting is troublesome. For this reason, wiring for detecting a disturbing action that is not related to normal alarm operation is often omitted, and there are cases where the wiring is used in a state where it does not have a sufficient function.
[0006]
In addition, a new security property can be tampered with a tamper loop using a tamper control board. However, there is a problem in existing properties that it is difficult to wire a new tamper function. .
[0007]
The present invention solves such a problem, and it is not necessary to provide a new wiring in addition to the wiring for a normal alarm, and it is easy to lay and low cost, and can be easily applied to an existing property. The purpose is to obtain a sensor.
[0008]
[Means for Solving the Problems]
In order to achieve the above object, a security sensor according to the present invention includes a sensor unit that detects an object and outputs a detection signal, an alarm command circuit that outputs an alarm signal based on the detection signal, and after power-on, A detection signal monitoring circuit that outputs a trouble signal when there is no detection signal within a predetermined time from the end of the unstable period of the detection signal, a sensor cover that covers the sensor unit, and detection of opening / closing of the sensor cover A tamper switch, and the detection signal monitoring circuit further detects the detection signal within the predetermined period from when the tamper switch detects that the sensor cover is closed and the unstable period of the detection signal ends. It is to determine the presence or absence .
The alarm command circuit described above performs a normal crime prevention action that operates when an intruding object is detected. On the other hand, the above-mentioned detection signal monitoring circuit detects that a disturbing action has been performed on the sensor unit when a normal operation is not performed (such as daytime when many people come and go), and generates a trouble signal. Output.
[0009]
The detection signal from the sensor section has an unstable period that fluctuates greatly immediately after the power is turned on. During this unstable period, the detection circuit outputs a signal that is equal to or greater than the threshold value even though there is no intruding object. Since the detection signal monitoring circuit may be operated, the detection signal monitoring circuit is not operated during this unstable period.
Since it is such a structure, in this invention, after the person who performed the obstruction act turns on a power supply, it can detect easily that the sensor part which should detect the person is not operating. In addition, the wiring required for the conventional tamper mechanism is not required, and it can be easily applied to an existing sensor not provided with the wiring for the tamper mechanism. .
[0010]
Moreover, according to this configuration, the present invention can also be applied mainly to a security sensor that does not turn off even when the sensor cover is opened.
For example, if an operator operates while opening the cover while the power is on, the tamper switch is turned off when the cover is opened, and the tamper switch is turned on when the cover is closed after the operation is completed. The timer starts measuring. If the power is turned on after the cover is closed, the timer starts measuring after the unstable period ends after the power is turned on. In either case, if the sensor unit does not output a detection signal while the timer measures a predetermined time, it is considered that a trouble has occurred (there was an obstruction). Therefore, it can be determined whether or not the sensor cover is opened because of an obstruction.
[0011]
In a preferred embodiment of the present invention, the trouble signal from the detection signal monitoring circuit is further held, and the trouble signal is held when the detection signal is input while the trouble signal is being held. Is provided with a holding circuit for resetting.
According to this configuration, if there is no disturbing action in the sensor unit or if the worker or the like is in the detection area after the disturbing action is eliminated, the sensor unit is easily reset and returns to normal operation.
[0012]
In a preferred embodiment of the present invention, the warm-up detection circuit further includes a warm-up detection circuit that detects the end of the unstable period of the detection signal and outputs a warm-up completion detection signal after the power is turned on. The circuit is configured to exclude the unstable period of the detection signal.
According to this configuration, the detection signal monitoring circuit can be functioned immediately after the warm-up is completed, so that no time is wasted and the occurrence of trouble (interfering action) can be detected at an early stage.
[0013]
Further, in a preferred embodiment of the present invention, the detection signal monitoring circuit further starts the measurement for a predetermined time after the warm-up detection circuit outputs the warm-up completion detection signal and ends the measurement. A timer for monitoring the presence or absence of the detection signal over a predetermined time is provided.
According to this configuration, it is possible to arbitrarily set the predetermined time during which monitoring is continued according to the environment in which the sensor is installed by the timer.
[0014]
In a preferred embodiment of the present invention, an output signal output when the tamper switch detects the closing of the sensor cover and a warm-up completion detection signal from the warm-up detection circuit are further input. An AND circuit, an OR circuit to which an output signal from the AND circuit and a warm-up completion detection signal are input, and a timer that is started by the output of the OR circuit, and the timer measures the predetermined time. During this time, the detection signal monitoring circuit is configured to monitor the presence or absence of the detection signal.
According to this configuration, since the AND circuit is provided, even if the sensor cover is closed and the tamper switch is switched, the detection signal monitoring circuit does not operate unless the warm-up of the sensor unit is completed. Further, since the OR circuit is provided, the detection signal monitoring circuit operates when the warm-up is completed regardless of whether the tamper switch is on or off.
[0015]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings.
1 and 2 are a block circuit diagram and a flowchart of an embodiment of the security sensor of the present invention.
[0016]
In FIG. 1, the security sensor of the present invention includes a sensor unit 2 having a detection element 1, an amplifier 21, and a first comparator 22, and an alarm command circuit 4 to which an output signal a1 from the first comparator 22 is input. A one-shot circuit (monostable multivibrator) 15 that receives the alarm signal a10 from the alarm command circuit 4, and a first output circuit that receives the output from the one-shot circuit 15 and operates the alarm output relay 6 and the display 7. 5 to form a normal alarm generation line. The outputs of the alarm output relay 6 and the trouble output relay 12 are sent to an alarm device or a monitoring room.
The security sensor according to the present invention includes a warm-up detection circuit 3 that operates upon receiving an ON signal from the power switch 20 and detects that the fluctuation of the signal from the amplifier 21 converges (the unstable period ends); When the warm-up detection signal a4 from the warm-up detection circuit 3 is input, the timer 8 starts, the detection signal monitoring circuit 9 monitors the presence or absence of the detection signal a1 during the timer output time, and the detection signal monitoring When a trouble signal a5 is output from the circuit 9, a holding circuit 10 that holds this output, and a second output circuit 11 that receives the output from the holding circuit 10 and operates the indicator 7 and the trouble output relay 12 are provided. And thereby form a monitoring line for monitoring the disturbing acts.
The detection signal a1 from the comparator 22 is also input to the holding circuit 10, and resets the holding of the trouble signal a5. The warm-up detection circuit 3 outputs the output inhibition signal a2 to the alarm command circuit 4 until the warm-up is completed.
[0017]
The detection element 1 reacts when an object such as a human body appears in the detection area. As the detection element 1, a passive infrared detection element (hereinafter referred to as “PIR element”) that receives an infrared ray from a human body and detects an intruder from a difference between the human body and ambient temperature can be used. In addition, a detection circuit using a Doppler effect that emits microwaves and receives microwaves having changed wavelengths reflected by a moving object can be used. Furthermore, a composite type sensing element in which these two types of sensing circuits are combined may be used. The complex detection circuit can detect an object more accurately. For example, when the room temperature suddenly changes due to a stove or the like, the Doppler sensor element that detects the movement of the object does not output a signal even if the PIR element that detects the temperature change erroneously outputs. On the other hand, when the curtain is swayed by the wind, the PIR element does not output a signal even if the Doppler sensor element outputs an error. If the two sensors detect both, it is sufficient to determine that the person is a thermal body and a moving body, and an intruder can be detected more accurately.
[0018]
The first comparator 22 outputs a detection signal a1 when the signal from the amplifier 21 exceeds a set threshold value. The warm-up detection circuit 3 includes a comparator (not shown) so that the amplified signal from the amplifier 21 is stabilized and approaches a certain value, that is, within a threshold value set by the comparator for a certain time. When the amplified signal is received, the end of the unstable period is detected, and the detection signal a1 is regarded as the end of the unstable period, and the detection signal a4 indicating the completion of warm-up is output. The alarm command circuit 4 is a circuit that generates a command to issue an alarm when the accumulated value of the detection signal a1 from the first comparator 22, for example, the integral value or the number of pulses becomes a certain value or more. The alarm command is output to the first output circuit 5 through the one-shot circuit 15, and an alarm is issued by the display 7 and the alarm output relay 7.
[0019]
The alarm output relay 6 and the trouble output relay 12 send alarm output to a control panel installed in another part of the same building or a control room of a security company, etc. Notify that there was an action. The indicator 7 is provided on the sensor main body or the mounting base, and lights up in response to the output from the first output circuit 5, while receiving the output from the second output circuit 11 and repeatedly flashes to cause trouble. Warning.
[0020]
The detection signal monitoring circuit 9 monitors the presence or absence of a detection signal at a predetermined time after turning on the power and excluding the unstable period when the output of the sensor unit is unstable. A memory 9a that receives the signal a1 and is turned on is incorporated. In this example, the timer 8 starts measuring a predetermined time upon receiving the detection signal a4 output upon detecting completion of warm-up, that is, the end of the unstable period. Until the measurement is finished, the detection signal monitoring circuit 9 is activated. However, the present invention is not limited to such a configuration. For example, the timer 8 may be omitted, and the detection signal monitoring circuit 9 may be set to operate for a predetermined time in response to the signal a4 from the warm-up detection circuit 3. Further, the timer 8 and the warm-up detection circuit 3 are omitted, and monitoring is performed after an on signal from the power switch 20 is input, that is, after a certain time (for example, 1 to 2 minutes) when the unstable period is expected to end. It may be set to start monitoring after a predetermined time (for example, another 5 minutes) has elapsed.
[0021]
Next, the operation of the security sensor according to the embodiment of the present invention will be described with reference to FIGS.
When the worker attaches the security sensor, the power is turned on, and it is determined whether or not the output of the amplifier 21 is stabilized by the warm-up detection circuit 3 (step S1 in FIG. 2). If the output of the amplifier 21 becomes stable, it is regarded as warm-up completion (S2), the timer-8 of the detection signal monitoring circuit 9 is started (S3), and simultaneously the detection signal memory 9a of the detection signal monitoring circuit 9 is set to OFF. (S4). It is determined whether or not the timer 8 is outputting (S5). If there is a detection signal a1 from the sensor unit 2 (S6), the detection signal memory 9a is set to ON (S7), but there is no detection signal. In this case, the detection signal memory remains off. When the timer 8 stops outputting after a predetermined time has passed, the detection signal memory is checked for ON / OFF (S8). If the detection signal memory is ON, the sensor unit 2 has worked normally and has detected a worker remaining in the detection area, so that the operation has been completed and the installation has been completed normally.
[0022]
On the other hand, if a malicious worker or a person who invades in the daytime in a non-warning state is performing a disturbing act before turning on the power, the sensor unit 2 does not operate normally. Even if the output of 8 stops, the detection signal memory 9a remains OFF, the detection signal monitoring circuit 9 outputs the trouble signal a5 to the holding circuit 10, and the holding circuit 10 holds the output (S9). If the detection signal a1 is not input to the holding circuit 10 as it is, the second output circuit 11 continues to operate (S10), and the display unit 7 and the trouble output relay 12 remain on to warn the disturbing action.
[0023]
In addition, if a worker goes out of the detection area before the end of the unstable period even though the sensor unit is operating normally, the trouble signal a5 is output once, but the worker is abnormal. If it is noticed and returns to the detection area, the detection signal a1 is output, the holding circuit 10 is reset, and the detection signal memory 9a of the detection signal monitoring circuit 9 is set to OFF (S11). Similarly, when an operator who has received a warning of disturbance removes the obstacle and restores the sensor operation to normal, the holding circuit 10 is reset by the detection signal a1 that detects the person, and the detection signal monitoring circuit 9 detection signal memory 9a is set to OFF (S11).
[0024]
Next, another embodiment will be described based on FIGS. 3 to 5.
In the security sensor of FIG. 3, a known tamper switch 13 is provided in addition to the circuit of the security sensor of FIG. 1, and detects the attachment / detachment of a sensor cover (not shown) that covers the sensor unit 2. When the sensor cover is removed, the tamper switch 13 outputs an off signal (low level signal) that indicates the opening of the sensor cover, and when the sensor cover is attached, the tamper switch 13 indicates that the sensor cover is closed. An ON signal (high level signal) that is a closing signal is output. When the sensor cover is opened by somebody and then closed and the signal is inverted from OFF to ON, this is detected by the open / close detection means 29 comprising a logic circuit, and a sensor cover closing detection signal a7 is output. The signal a7 is delayed for a certain time by the signal delay circuit 31 and then input to the AND circuit 25, and an output signal is input from the holding circuit 32 of the warm-up completion detection signal a4 from the warm-up detection circuit 3. For example, the AND circuit 25 outputs a signal to the OR circuit 26 and starts the timer 8 via the OR circuit 26. The OR circuit 26 also receives a detection signal a4 from the warm-up detection circuit 3. Therefore, when the power is turned on and the warm-up is completed, the timer 8 starts immediately via the OR circuit 26. However, if the sensor cover is attached and the tamper switch turns from OFF to ON, the warm-up is completed. Wait for the timer to start.
[0025]
The operation of the security sensor configured as described above will be described with reference to FIGS.
It is determined whether or not the output of the amplifier 21 is stabilized by the warm-up detection circuit 3 in FIG. 3 (step S21 in FIG. 4), and when this output is stabilized, it is considered that the warm-up is completed (S22). When the warm-up is completed and the tamper switch 13 is switched from OFF to ON (S33), the timer 8 starts (S23).
Thereafter, as in FIG. 1, when the detection signal memory 9a is set to OFF (S24) and the sensor cover is opened and closed after the timer is started and the tamper switch 13 is switched from OFF to ON, the timer start signal is input again. In response to this, the timer 8 is restarted (S25). If there is no restart, the timer output is maintained and the presence or absence of the detection signal a1 during the timer output is monitored (S26, S27, S28). If the detection signal a1 is present, the operation is terminated (S29). If the detection signal a1 is not present, the output for the trouble warning is temporarily held (S30), and the detection signal a1 after the recovery is waited for input (S30). S31, S32).
[0026]
According to this configuration, the present invention can be applied to a security sensor that does not turn off even when the sensor cover is opened. If the circuit shown in FIG. 1 is used for a type that does not turn off even if the sensor cover is opened, the power switch 20 can be turned on even if the sensor cover is closed after the internal sensing element 1 is disturbed. Is not input to the warm-up detection circuit 3, the detection signal monitoring circuit 9 does not operate, and such a disturbing action cannot be detected. As shown in FIG. 3, by providing the tamper switch 13, it is possible to detect such a disturbing action and to determine whether or not the sensor cover is opened because of the disturbing action. Also, the provision of the signal delay circuit 31 for the tamper signal can eliminate the effect of the detection signal input by opening the cover. This delay is suitably 5 to 10 seconds.
[0027]
FIG. 5A shows an example of a tamper output circuit. A capacitor 16, a resistor 17 connected between the capacitor 16 and the ground, and a diode 18 connected in a reverse direction between the capacitor 16 and the ground are connected to the contact A on the ground side of the tamper switch 13 connected to the power source _Vcc. A differentiating circuit 14 is connected. A pulse discriminating circuit 19 is connected to the output terminal B to extract an output signal, and a differential signal a6 (see FIG. 5B) is discriminated. The differentiation circuit 14 and the pulse discrimination circuit 19 are built in the open / close detection means 29 of FIG. Thus, only when the voltage level at the connection point A shown in FIG. 5A is reversed from low (zero) to high (V _cc ) by turning the tamper switch 13 from OFF to ON, the voltage level shown in FIG. As shown, an inversion signal a6 is output, and the open / close detection means 29 in FIG. 3 receiving this signal a6 delays a high level open / close detection signal (sensor cover close detection signal) a7 by the signal delay circuit 31, Output to the AND circuit 25. The diode 18 is for protecting the pulse discrimination circuit 19 connected to the connection point B.
[0028]
FIG. 6 shows a modification of the tamper output circuit. This example can be applied when the tamper switch 13 is connected to the tamper loop provided separately from the sensor loop. In this case, since the tamper loop opening / closing terminal needs to be separated from the sensor circuit, a double switch is used as the tamper switch, and the tamper loop is opened / closed by the first switch unit 13a to send the tamper signal to the alarm device. When the second switch portion 13b is opened or closed, an opening / closing signal is input to the differentiation circuit 14 of the opening / closing detection means 29 of the sensor circuit.
[0029]
Next, still another embodiment will be described based on FIG.
7 is different from the embodiment of FIG. 1 in that the sensor unit 2 has two comparators 22 and 23, and two threshold values are set for a normal alarm generation line and a monitoring line for monitoring a disturbing action. It is a point that has been set. The first comparator 22 is connected to the alarm command circuit 4, and the second comparator 23 is connected to the detection signal monitoring circuit 9. If the threshold value of the second comparator 23 is made lower than the threshold value of the first comparator 22, the detection signal a8 is detected from the second comparator 23 even when a low level signal is received from the detection element 1. Since the signal is input to the signal monitoring circuit 9, it can be detected even when the response of the detection element 1 to the worker after installation is slow.
[0030]
Further, in the embodiment of FIG. 7, the trouble output relay 12 (see FIG. 1) is omitted, and the alarm output relay 6 is also output when a trouble occurs. According to this configuration, wiring to the trouble output relay 12 can be omitted, and a simpler configuration can be achieved.
Further, in the embodiment of FIG. 7, the warm-up detection circuit 3 detects the end of the unstable period of the detection signal a1 because the detection signal a1 from the first comparator 22 does not occur for a certain period of time. In this case, the warm-up detection circuit 3 does not need to include a comparator.
[0031]
【The invention's effect】
According to the security sensor of the present invention, the power supply wiring for driving the sensor unit is configured to detect the presence or absence of an object for a predetermined time when the signal of the detection element is stable after the power is turned on. In addition, it has a simple structure that does not require other wiring and can be easily installed. In addition, existing sensors can be easily used. Therefore, the security company can detect an obstruction to the security sensor at an early stage by simply replacing this sensor with the existing system, and can prevent crime in advance.
[Brief description of the drawings]
FIG. 1 is a block diagram according to an embodiment of the present invention.
FIG. 2 is a flow chart of a security sensor having the block diagram of FIG.
FIG. 3 is a block diagram according to another embodiment of the present invention having a tamper switch.
4 is a flowchart of a security sensor having the block diagram of FIG.
FIG. 5 is a diagram illustrating an example of a tamper switch.
FIG. 6 is a diagram showing a modification of the tamper switch.
FIG. 7 is a block diagram according to still another embodiment of the present invention in which a plurality of comparators are provided.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Detection element, 2 ... Sensor part, 3 ... Warm-up detection circuit, 4 ... Alarm command circuit, 5 ... 1st output circuit, 6 ... Alarm output relay, 7 ... Display, 8 ... Timer, 9 ... Detection signal monitoring Circuit: 10: Holding circuit, 11: Second output circuit, 12: Trouble output relay, 13: Tamper switch, 25: AND circuit, 26: OR circuit, a1: Detection signal, a4: Detection signal for completion of warm-up, a5 ... trouble signal, a7 ... sensor cover closed detection signal, a10 ... alarm signal

Claims (5)

A sensor unit that detects an object and outputs a detection signal;
An alarm command circuit for outputting an alarm signal based on the detection signal;
A detection signal monitoring circuit that outputs a trouble signal when there is no detection signal within a predetermined time after the unstable period of the detection signal ends after turning on the power;
A sensor cover that covers the sensor unit; and a tamper switch that detects opening and closing of the sensor cover.
The detection signal monitoring circuit further detects a presence / absence of a detection signal within the predetermined period from when the tamper switch detects that the sensor cover is closed and the unstable period of the detection signal ends. . 2. The holding circuit according to claim 1 , further holding the trouble signal from the detection signal monitoring circuit and resetting the holding of the trouble signal when the detection signal is input during holding of the trouble signal. Security sensor equipped with. 3. The warm-up detection circuit according to claim 1 , further comprising a warm-up detection circuit that detects the end of the unstable period of the detection signal after power-on and outputs a warm-up completion detection signal. Security sensor excluding unstable period of detection signal. 4. The detection signal monitoring circuit according to claim 3 , further comprising: starting a measurement for a predetermined time after the warm-up detection circuit outputs a warm-up completion detection signal, and allowing the detection signal monitoring circuit to detect the detection for the predetermined time until the measurement is completed. Security sensor with a timer that monitors the presence or absence of a signal. The AND circuit according to claim 3 , further comprising: an AND circuit to which an output signal output when the tamper switch detects closing of the sensor cover and a warm-up completion detection signal from the warm-up detection circuit are input; An OR circuit to which an output signal from the AND circuit and a warm-up completion detection signal are input, and a timer that is activated by the output of the OR circuit, and the detection is performed while the timer is measuring the predetermined time. A security sensor for causing a signal monitoring circuit to monitor the presence or absence of the detection signal.

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