JPH04190500A - Guard system - Google Patents

Abstract

PURPOSE:To judge whether a sensor is abnormal or normal and to realize secure guard by installing a heating element in a guard area and generating a detection signal by a passive type infrared-ray detection sensor when the sensor arranged in the guard area is tested periodically. CONSTITUTION:The passive type infrared-ray detection sensor 1, the heating element 2, and a temperature sensor 3 are installed in a room R and detection areas E1 - E3 to be guarded are arranged in the room R. Then a test mode is set up at test time set and stored in a RAM 3c. At this time, when the temperature of the heating element 2 measured by the sensor 3 reaches set temperature, it is decided whether or not the sensor 1 outputs the detection signal. The temperature of the heating element 2 is controlled by a CPU 3a to constant temperature regardless of a season and weather. Consequently, the detection sensitivity of the sensor 1 is corrected automatically and periodically to constant sensitivity. Therefore, an illegal trespasser can securely be detected.

Description

[Detailed Description of the Invention] <Field of Industrial Application> The present invention relates to a security system that monitors the presence or absence of illegal intruders in a restricted area using a passive infrared detection sensor and issues an alarm when an illegal intruder is detected. It is something.

BACKGROUND OF THE INVENTION Passive infrared detection sensors in such security systems are sometimes destroyed by would-be trespassers to prevent them from issuing alarms.

For example, during the daytime when the security system is turned off due to the need to freely enter and exit the guarded area, a sensor may be destroyed, short-circuited, or the detection area changed to an unnecessary location, and an intrusion attempt may be attempted at night. There are times when I get tired.

As a measure to prevent such things from happening, we have installed a so-called tambour protection structure in which the cover of the sensor is removed and an alarm sounds, or a heat source is installed inside the passive infrared detection sensor. The sensor has a function of periodically driving the heat source to check whether there is any abnormality in the operation of the sensor itself.

<Problems to be Solved by the Invention> However, if the infrared transmitting window to the infrared detecting element of the sensor is shielded so as not to transmit infrared rays by means such as spraying paint from the outside of the cover, the above-mentioned problem will occur. A tamper-proof structure is useless, and on the other hand, a sensor with an internal heat source uses the internal heat source to determine that there is no abnormality during regular checks, even though it cannot detect a human body. This results in the inconvenience of not noticing sensor abnormalities.

The present invention has been made in view of such conventional problems, and is capable of reliably detecting even if an infrared transmitting window is blocked by a passive infrared detection sensor or a means that does not contact the cover from the outside. The technical problem is to provide a security system that can automatically correct the detection sensitivity of the sensor to be constant according to changes in the background temperature of the detection area. .

Means for Solving the Problems> In the present invention, as a technical means for achieving the above-mentioned problems, a security system is configured as follows. In other words, in a security system that detects the intrusion of a human body or the like into a guarded area and issues an alarm, a passive infrared detection sensor is installed with a detection area set in the guarded area, and a passive infrared detection sensor is installed at a location within the detection area. a controller that drives the heating element only during a test mode and determines whether or not there is an abnormality in the infrared detection sensor based on whether or not the infrared detection sensor outputs a detection signal due to heat generated by the infrared detection sensor or the heating element; It is characterized by the following:

Further, the controller includes a sensitivity correction means for variably dividing the detection sensitivity of the infrared detection sensor so that the light reception signal level of the infrared detection sensor is within a predetermined range when the heating element reaches a predetermined temperature during test mode. You can also prepare.

If the infrared transmitting window of the cover is blocked due to adhesion of paint from spraying, etc., for example, during periodic test mode, the sensor's infrared transmitting window may be exposed to infrared rays due to heat generated by the heating element driven by the controller. If the sensor is blocked without passing through and no detection signal is output from this sensor even though the heating element is being driven, it is determined that there is an abnormality in the controller or sensor. On the other hand, when a detection signal is output from the sensor, the controller determines that the sensor is normal.

In addition, if the controller is provided with a sensitivity correction means, after the controller determines that the sensor is normal during the test mode, the sensitivity correction means adjusts the detection sensitivity of the sensor so that the light reception signal level of the sensor is within a predetermined range. Make it variable. Here, the controller determines whether the signal level of the sensor is within a predetermined range when the temperature of the heating element becomes constant, regardless of changes in the background temperature of the detection area due to the season or the weather of the day. Therefore, the light reception signal level of the passive infrared sensor that detects the difference between the background temperature and the heating element temperature changes depending on the background temperature, and when the signal level falls outside the predetermined range, the sensitivity correction means or the The detection sensitivity of the sensor is adjusted to a variable level so that the sensor's detection sensitivity remains within the range, and the detection sensitivity of the sensor is automatically corrected so that it always remains constant according to the season and temperature.

<Embodiments> Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings.

FIG. 1 shows a block configuration of an embodiment of the present invention, and a room R in a guarded area is shown in a plan view. Then, in one corner of this room R, passive infrared detection sensor 1 or its detection areas E1 to E3 are set and placed at areas that need to be guarded within room R, and one of these detection areas E3 is placed within the detection area E3. A heating element 2 incorporating heating wires on the wall of room R,
Temperature sensor 3 that measures the temperature due to heat generated by this heating element 2
It is set up.

As shown in the block diagram in the same figure, the passive infrared detection sensor 1 converts the amount of infrared energy from the detection areas E1 to E3, which is focused and incident by the optical system 1a, into an electric signal proportional to the fluctuation thereof. an infrared detection element 1b;
An amplifier 1c that amplifies the electric signal (light reception signal) from the infrared detection element 1b, and a level detection circuit 1d that constantly monitors fluctuations in the amplified signal and outputs a detection signal when a fluctuation exceeding a set detection level is detected. It is made up of.

The controller 3 is configured as follows.

That is, the central processing unit 3a consisting of a microcomputer
controls the entire system based on a program stored in advance in the ROM 3d, and sets the test mode when the test time comes based on the clock signal from the clock circuit 3b and the test time data set and stored in the RAM 3c. However, when it is determined that the sensor 1 is abnormal based on the result of the test mode, an alarm 7 consisting of a buzzer or an indicator light is driven via the output circuit 6 to notify of the abnormality. Normally, when a detection signal is output from the sensor 1, an alarm device 5 consisting of a buzzer or a light is activated via the output circuit 4 to issue an alarm.

Next, the operation of the above embodiment will be explained based on flowchart 4 in FIG. 2. The RAM 3c stores in advance a test time such as the time to start the daily alert state or the time every two hours, and the central processing unit 3a
Based on the test time data from the RAM 3c and the clock signal from the clock circuit 3b, it is constantly monitored to see if it is the eggplant 1~ time (step Sl), and when the test time comes, the heating element 2 is turned off. A command is issued (step S2) to set a test mode other than normal operation, and it is determined whether the temperature measured by the temperature sensor 3 or the set temperature preset and stored in the RAM 3c has been reached (step S3).

This set temperature is set to a temperature that generates approximately the same amount of infrared rays as the human body. Therefore, if the heating area of the heating element 2 is small, the temperature is set to be slightly higher than the human body temperature of 36°C. The central processing unit 3a controls the power supplied to the heating element 2 to be increased until the temperature measured by the temperature sensor 3 reaches the set temperature.

Then, when the temperature measured by the temperature sensor 3 of the heating element 2 reaches the set temperature, it is determined whether the passive infrared detection sensor 1 outputs a detection signal (step S4). If sensor 1 is normal, it detects the infrared rays generated by heating element 2 and outputs a detection signal.
It is determined whether the difference between the sensor signal level outputted from the sensor 0 and the detection level set by the level detection circuit 1 is within a predetermined range (step knob S5). Here, the temperature of the heating element 2 is controlled to be constant by the central processing unit 3a regardless of changes in the background temperature of the detector IJA due to seasons, weather, etc. The sensor signal level of the passive infrared sensor 1 that detects the difference from the temperature changes depending on the background temperature (if the detection level is constant, the difference from the sensor signal level will be outside the predetermined range. In that case The detection level of the level detection circuit 1d is varied so that the above-mentioned difference falls within a predetermined range, and the detection sensitivity is automatically corrected (step S6).Therefore, the detection sensitivity of the sensor 1 is adjusted regardless of the season or weather. It is periodically and automatically corrected so that it always remains constant.

After that, the power supply to the heating element 2 is stopped (step S7
), wait for the next test time. Therefore, the test mode is set at regular intervals and the above-described test operation is performed.

In the unlikely event that the infrared transmitting window of the cover of the sensor 1 is blocked due to adhesion of paint from spraying or the like, the heating element 2 is driven by the central processing unit 3a during the aforementioned test mode, or the heating element 2 is The infrared rays due to the heat generated by the infrared rays are blocked without passing through the infrared transmitting window, and in step S4, when no detection signal is output from the sensor 1, it is determined that there is an abnormality, and the alarm 7 is driven via the output circuit 6 to notify the abnormality. (Step S8).

On the other hand, outside of test times, it functions as a normal security system. That is, if the determination in step S1 is always NO and a detection signal is output from the sensor 1, it is constantly monitored (step S9), and if a detection signal is output, the alarm 5 is driven via the output circuit 4. (Step 5)
10).

3 and 4 show other embodiments of the present invention, illustrating a case where a guarded area is monitored by two passive infrared detection sensors 8 and 9, and each of the sensors 8 and 9 Detection areas E4 to E6. Most of the interior of the room can be monitored by E7 to E9.

As shown in FIG. 4, each sensor 8, 9 has a heating element 1, which is a heater, located below the infrared detection element 10.
The cover 12 is provided with a shutter 13 that can be opened and closed at a location opposite the heating element 11. Incidentally, the cover 12 is provided with a condenser lens 14 at a location opposite to the infrared detecting element 10 and a display window 16 at a location opposite to the operation indicator light 15, respectively, as in the existing one.

As shown in FIG. 3, each sensor 8, 9 has a mutual detection area E6. It is attached to the wall inside E9. Therefore, there is no need to separately provide only the heating element 2 as shown in FIG. It will open automatically,
Temperature sensor is no longer needed. Testing of each sensor 8, 9 is carried out in substantially the same manner by a controller 3 similar to that shown in FIG.

FIG. 5 shows still another embodiment of the present invention, in which, in addition to monitoring a guarded area using the detection areas E1 to E3°EIO of the passive infrared detection sensor 1, the windows 17 and entrances and exits 18 are in particular equipped with a floodlight 19 and a light receiving device. When monitoring with a photoelectric switch consisting of a sensor 20, the heating element 21 is integrated into the floodlight 19 installed in the detection area E3 of the sensor 1, thereby saving the trouble of separately arranging only the heating element 21. It is something.

In each of the above embodiments, the passive infrared detection sensor and the controller are provided separately.
Of course, the sensor and controller can also be integrated.

<Effects of the Invention> As described above, according to the security system of the present invention, even if the infrared transmitting window of the passive infrared detection sensor is blocked by paint adhesion from the outside, it is possible to detect the It is possible to accurately identify and provide reliable security.

In addition, the detection sensitivity of the sensor can be automatically corrected using the sensor signal level of the sensor when the heating element reaches a predetermined temperature. Detection sensitivity can be kept constant at all times, making it possible to reliably detect illegal intruders.

[Brief explanation of the drawing]

Figure 1 is a block diagram of an embodiment of the present invention, Figure 2 is a flowchart thereof, Figure 3 is a schematic diagram of another embodiment of the invention, and Figure 4 is a perspective view of its sensor. , FIG. 5 is a schematic configuration diagram of still another embodiment of the present invention. 1, 8. 9... Passive infrared detection sensor 2.11
．． 21...Heating element 3...Controller 5...Alarm device patent application Person Saiputex Co., Ltd.
Rihito Nishi 1) New Figure 3 Figure 4

Claims (2)

[Claims] (1) In a security system that detects the intrusion of a human body, etc. into a guarded area and issues an alarm, a passive infrared detection sensor is installed with a detection area set in the guarded area, and a passive infrared detection sensor is deployed at a location within the detection area. and a controller that drives the heating element only in a test mode and determines whether or not there is an abnormality in the infrared detection sensor based on whether or not the infrared detection sensor outputs a detection signal due to the heat generated by the heating element. A security system characterized by being equipped with. (2) The controller includes a sensitivity correction means for variably controlling the detection sensitivity of the infrared detection sensor so that the level of the light reception signal of the infrared detection sensor falls within a predetermined range when the heating element reaches a predetermined temperature in the test mode. The security system according to claim 1, further comprising a security system.