JPH04340193A - Hot-wire type detector - Google Patents

Abstract

PURPOSE:To automatically and periodically check operation by providing a hot-wire type detector for detecting the existence of a human based upon heat radiated from a human body with a self-diagnostic function. CONSTITUTION:In the hot-wire type detector having a detection part 1 provided with a pyroelectric element 2 for detecting heat radiated from a human body and a heating body 3 arranged in the vicinity of the element 2 and generating heat by impressing voltage to execute the self-diagnosis of the element 2, a switching means 9 is turned on when a charging voltage for charging a power supply voltage through a current adjusting resistor 7 reaches a regulated voltage and held at ON for a prescribed period and the heating body 3 is driven to automatically and periodically check the operation. When a detection signal from the element 2 is obtained by driving the heating body 3, the sending of an alarm signal to the external based upon the output of the element 2 may be inhibited.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hot-wire type detector for detecting the presence of a person from the heat emitted from the human body.

0002

[Prior Art] Conventionally, in a hot-wire type detector used for example in a theft monitoring device, a pyroelectric element detects heat rays emitted from a human body, and when the detection output exceeds a predetermined threshold, an alarm signal is issued. is sent to the receiver to display an alarm. In such crime prevention monitoring devices, by disabling the alarm set on the receiver during daytime hours when people are around, the receiver ignores the signal from the hot-wire detector, while at night when there are no people around. If there is an intruder, the receiver will issue an alarm based on the alarm signal from the hot-wire detector, and a security company will be alerted. Automatic notifications are sent via telephone line.

0003

[Problems to be Solved by the Invention] However, with such conventional hot-wire type human body detectors, when checking the operation during maintenance and inspection, it is difficult for a person to walk through each warning area and detect the hot-wire type human body detector. The operation is checked based on whether or not an alarm is issued, and there is a problem in that it takes a lot of time and effort to check the operation.

[0004] Furthermore, there is a problem in that there is no means to check whether the detector is operating normally when setting the alarm, and even if there is a malfunction, the alarm continues to be carried out. The present invention was made in view of these conventional problems, and an object of the present invention is to provide a hot-wire type detector in which the detector is equipped with a self-diagnosis function so that operation can be automatically and periodically checked. purpose.

[0005]

[Means for Solving the Problems] In order to achieve this object, the present invention is constructed as follows. In addition, the reference numerals in the drawings of the embodiments are also shown. First, the present invention provides a pyroelectric element 2 that detects heat emitted from a human body, and a heating element that is installed near the pyroelectric element 2 and that generates heat by applying a voltage to self-diagnose the pyroelectric element 2. The present invention is directed to a hot-wire type detector 100 that has a detection section 1 having a detection section 3 and detects the presence of a human body based on the detection output of the detection section 1.

In the present invention, such a hot wire type detector 100 includes a charging section 8 that charges the power supply voltage via the current adjustment resistor 7, and a switch that applies the output voltage of the charging section 8 to the heating element 3. It is characterized by comprising a means 9 and a comparison control section 10 which turns on the switch means 9 for a predetermined period of time to drive the heating element 3 when the charging voltage of the charging section 8 reaches a specified voltage.

Furthermore, in the present invention, when a detection output is obtained from the pyroelectric element 2 by driving the heating element 3, sending out an alarm signal to the outside based on the output of the pyroelectric element 2 is prohibited. It is characterized in that means (16, 17, 18, 19) are provided.

[0008]

[Function] According to the hot wire type detector of the present invention having such a configuration, the heating element 3 of the detection unit 1 is driven at predetermined time intervals determined by the time constant of the capacitor of the charging unit 8 and the current adjustment resistor 7. A voltage is applied, and the pyroelectric element 2 receives heat from the heating element 3.
or generates a detection output for self-diagnosis. When this detection output exceeds a threshold value, an alarm signal is sent to the receiver side.

[0009] The receiver determines whether the detector is operating normally from receiving periodic alarm signals based on self-diagnosis, that is, from periodic notifications, and if there is no periodic notification, it can determine whether the detector is operating abnormally. It is also possible to prohibit the sending of a warning signal during self-diagnosis and send a warning signal only when an abnormality occurs. Furthermore, the alarm signal and the self-diagnosis signal can be sent separately, and only the self-diagnosis signal is allowed to be sent during self-diagnosis. In this way, a check of the operation of the detector is carried out automatically and periodically.

0010

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a block diagram showing an embodiment of the present invention. In FIG. 1, 100 is a hot wire type detector of the present invention, and 200 is a classification indicator on the receiver side. The hot wire detector 100 is provided with a detection section 1 . The detection unit 1 includes a pyroelectric element 2 that detects heat emitted from the human body, and a heat generating element that is provided near the pyroelectric element 2 and generates heat by applying a voltage to self-diagnose the pyroelectric element 2. A body 3 is provided.

The detection signal from the pyroelectric element 2 provided in the detection section 1 is amplified by an amplifier 4 and then applied to a comparator 5. A predetermined threshold value is set in the comparator 5,
The detection signal from amplifier 4 produces a comparison output when it exceeds a threshold value. The comparison output of the comparator 5 is given to the alarm output section 6,
An alarm signal is sent to the division display 200 via the signal line L1, and the division display 200 displays, for example, a theft alarm.

Power is supplied from the classification display 200 to the hot wire type detector 100 via a power line L2, and this power line L2 is connected to a charging section 8 via a current adjustment resistor 7. The charging unit 8 includes a capacitor, and is charged to the power supply voltage according to a time constant with the current adjustment resistor 7. The charging voltage of the charging section 8 is applied to the heating element 3 of the detecting section 1 via the switch means 9.

The switching means 9 is turned on and off by a comparison control section 10. The comparison control unit 10 monitors the charging voltage of the charging unit 8, and when the charging voltage reaches a specified voltage,
The switch means 9 is turned on for a certain period of time, and the charging voltage charged in the charging section 8 is applied to the heating element 3 to drive the heating element, thereby causing the pyroelectric element 2 to perform a self-diagnosis. FIG. 2 is a circuit diagram showing details from the current adjustment resistor 7 to the heating element 3 of the detection section 1 in the embodiment of FIG.

In FIG. 2, first, the detection unit 1 has a pair of pyroelectric elements 2a and 2b connected in series, and receives the heat rays emitted from the human body by the pyroelectric elements 2a and 2b, and outputs the addition of differential detection signals. will occur. The detection output of the pyroelectric elements 2a and 2b is F
It is applied to the gate of the FET 11, controls the degree of conductivity of the FET 11 using the detection signals of the pyroelectric elements 2a and 2b, and controls the current flowing from the drain terminal 13 to the source terminal 14.

A signal corresponding to the current flowing through the drain terminal 13 and the source terminal 14 becomes a detection signal of the pyroelectric element 2 for the amplifier 4 in FIG. The heating element 3 of the detection unit 1 is connected between the self-diagnosis terminal 12 and the common terminal 15, and by applying a voltage to the self-diagnosis terminal 12, the heating element 3 is driven, giving heat to the pyroelectric elements 2a and 2b. A detection operation for self-diagnosis can be performed.

The pyroelectric elements 2a, 2b, heating element 3 and F
The detection unit 1 including the ET 11 is packaged as one IC. A resistance R is applied to the heating element 3 of the detection unit 1.
The emitter of a transistor 9 serving as a switch means is connected via 3. A capacitor 8 serving as a charging section is connected to the collector side of the transistor 9, and a power supply voltage Vcc is applied to the capacitor 8 via a current adjustment resistor 7.

The charging voltage of the capacitor 8 is determined by the comparison control section 10.
The reference voltage Vref is applied to the plus input terminal of the comparator 10a, and the reference voltage Vref divided by resistors R1 and R2 is set to the minus input terminal. The comparator 10a goes high when the charging voltage Vc of the capacitor 8 exceeds the reference voltage Vref.
Produces level output. The output of the comparator 10a is given to the pulse drive circuit 10b, and upon receiving the comparator output, the pulse drive circuit 10b turns on the transistor 9 for a certain period of time.

Here, the resistance value of the current adjustment resistor 7 is set to a sufficiently large resistance value, and the charging voltage Vc of the capacitor 8 is charged to the reference voltage Vref in units of, for example, time order from the start of charging. For example, once every hour, the transistor 9 is switched on by the comparator 10a and the pulse drive circuit 10b that constitute the comparison control section 10.

Next, the operations in FIGS. 1 and 2 will be explained. When the warning set state is set by operating the set switch etc. of the classification display 200, the power line L2 is connected to the hot wire detector 100.
A power supply voltage is supplied through the circuit, and the device becomes operational. The power supply voltage from the segment display 200 starts charging the charging unit 8, ie, the capacitor 8, via the current regulating resistor 7. The charging voltage Vc of the capacitor 8 reaches the reference voltage Vref, for example, one hour after the start of power supply, the comparator 10a produces a comparison output, and the pulse drive circuit 10b turns on the transistor 9 for a certain period of time.

When the transistor 9 is turned on, the electric charge charged in the capacitor 8 is applied to the heating element 3 provided in the detection section 1 via the transistor 9 and the resistor R3.
Heat is generated from the pyroelectric elements 2a and 2b for self-diagnosis. Pyroelectric elements 2a, 2 receiving heat from heating element 3
b, i.e. the pyroelectric element 2 of FIG. 1 produces a detection output and the amplifier 4
If the pyroelectric element 2 is normal, the detection signal exceeds the threshold value, so the comparator 5 generates a comparison output, and an alarm signal is sent from the alarm output section 6 via the signal line L1. is provided to the segment display 200.

The classification display 200 periodically monitors whether or not an alarm signal is obtained from the hot wire detector 100, and if an alarm signal is obtained periodically, for example once every hour. In other words, if the detection side sends a regular report, it is determined that the hot wire detector 100 is operating normally. On the other hand, if a failure occurs in the pyroelectric element 2 or other circuit section of the hot-wire detector 100, the hot-wire detector 100 periodically becomes unable to generate an alarm signal, and the regular alarm signal An abnormality in the hot-wire type detector 100 can be known by determining the stoppage of receiving regular notifications, that is, the stoppage of regular notifications, using the classification display 200.

FIG. 3 is a block diagram showing another embodiment of the present invention, which is characterized in that the transmission of the alarm signal is prohibited if the inspection is normal. First, Figure 3(a)
, a detection unit 1 including a pyroelectric element 2 and a heating element 3;
Amplifier 4, comparator 5, alarm output section 6, current adjustment resistor 7,
The configurations of the charging section 8, switch means 9, and comparison control section 10 are the same as those in the embodiment shown in FIG.

In addition, in the embodiment shown in FIG. 3, the outputs of the comparator 5 and the comparison control section 10 are applied to the alarm output section 6 via the EX-OR circuit 16. Here, the output of the comparator 5 is A, the output of the comparison control section 10 is B, that is, EX-OR
If the inputs to the circuit 16 are A and B, and the output of the EX-OR circuit 16 is C, then the EX-OR circuit 16 in each state
The input/output relationship is as shown in FIG. 3(b).

That is, during normal monitoring, since both the outputs of the comparator 5 and the comparison control section 10 are at the L level, EX
-The output C of the OR circuit 16 is at L level. During the test operation, the output B of the comparison control section 10 becomes H level, and if the pyroelectric element 2 is normal, the output A of the comparator 5 also becomes H level, and as a result, the output C of the EX-OR circuit 16 becomes L level. be.

On the other hand, if there is a malfunction during the test, the output A of the comparator 5 becomes L level, so the output C of the EX-OR circuit 16 becomes H level, and the alarm output section 6 outputs the alarm signal. Send. Furthermore, when detecting a human body, the output B of the comparison control section 10 is at the L level, and the output A of the comparator 5 is
is at H level, the output C of the EX-OR circuit 16 is at H level.
level, and the alarm output unit 6 operates to send an alarm signal to the classification display 200.

FIG. 4 is a block diagram showing another embodiment of the present invention, and this embodiment is characterized in that an alarm signal and a self-diagnosis signal are sent out separately. do. In FIG. 4, the configuration from the detection section 1 to the comparison control section 10 is the same as that in FIG. In addition, in the embodiment shown in FIG. 4, a diagnosis output section 20 is provided for individually outputting a self-diagnosis signal to the alarm output section 6.

Further, the output of the comparator 5 is applied to the alarm output unit 6 via an AND circuit 17, and is also applied to the diagnosis output unit 20 via an AND circuit 18. The output of the comparison control section 10 is connected to the other input of the AND circuit 17.
Input via . Further, the output of the comparison control section 10 is directly applied to the other input of the AND circuit 18. Therefore, the H level output of the comparison control section 10 during the test is inverted by the inverter circuit 19, and the AND circuit 17 becomes inhibited, and the alarm output section 6 stops sending out the alarm signal based on the output of the comparator 5. prohibit.

At the same time, the H level output of the comparison control section 10 puts the AND circuit 18 into a permissive state, allowing the diagnosis output section 20 to send out a self-diagnosis signal based on the output of the comparator 5. The self-diagnosis signal from the diagnosis output section 20 is transmitted through the signal line L3.
is provided to the division display 200 via. The classification display 200 is provided with an alarm indicator light and a self-diagnosis indicator light corresponding to each warning area, and if a self-diagnosis signal is normally obtained during a regularly conducted test, the self-diagnosis indicator light is turned on.

For this reason, it can be determined that the hot wire detector 100 whose self-diagnosis indicator lamp is not illuminated is malfunctioning during periodic testing. In addition, although the above-mentioned embodiment took as an example the case where the hot-wire type detector of the present invention is used in a crime prevention monitoring device, the present invention is not limited to this, and the present invention can be used as a room occupancy detector to detect illumination. Of course, it is also possible to perform control or the like.

[0030]

As explained above, according to the present invention, the detector itself periodically and automatically performs a self-diagnosis operation of the pyroelectric element by driving the heating element, thereby improving the reliability of the detector. It can be significantly improved. In addition, since the test time is determined by the RC charging section and the charging voltage is supplied to the heating element to perform the self-diagnosis test operation, the current consumption is small even when the heating element is driven, and multiple Even if a hot wire type detector is connected, the power supply capacity on the receiver side can be kept to the minimum necessary.

[Brief explanation of drawings]

[Fig. 1] An embodiment configuration diagram showing one embodiment of the present invention.

[Figure 2
】Circuit diagram showing the main parts of Figure 1 in detail

[Fig. 3] Embodiment configuration diagram showing another embodiment of the present invention

[Fig. 4] Embodiment configuration diagram showing another embodiment of the present invention.

[Explanation of symbols]

1: Detection part 2, 2a, 2b: Pyroelectric element 3: Heating element 4: Amplifier 5: Comparator 6: Alarm output section 7: Current adjustment resistor 8: Charging part (capacitor) 9: Switch means (transistor) 10: Comparison control section 10a: Comparator 10b: Pulse drive circuit 11: FET 12: Self-diagnosis terminal 13: Drain terminal 14: Source terminal 15: Common terminal 16: EX-OR circuit 17, 18: AND circuit 19: Inverter circuit 100: Hot wire detector 200: Classification indicator (receiver)

Claims (2)

[Claims] Claim 1: A pyroelectric element that detects heat emitted from a human body; and a heating element that is installed near the pyroelectric element and that generates heat by applying a voltage to self-diagnose the pyroelectric element. In a hot wire type detector that detects the presence of a human body based on the detection output of the detection section, the hot wire detector has a detection section equipped with a charging section that charges the power supply voltage through a current adjustment resistor, and an output of the charging section. A comparison control section that turns on the switch means for a predetermined period of time to drive the heat generating element when the charging voltage of the charging section reaches a specified voltage. Features a hot wire detector. 2. The hot-wire detector according to claim 1, wherein when a detection output is obtained from the pyroelectric element by driving the heating element, an output is emitted to the outside based on the output of the pyroelectric element. A hot wire type detector characterized by being provided with a means for prohibiting the transmission of a notification signal.