JPS63158697A - Sensor for disaster prevention - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] "Industrial Application Field" The present invention provides a detecting section that emits light, radio waves, sound waves, etc., and allows the emitted light to enter directly or indirectly, thereby reducing the amount of light incident on the detecting section. This relates to a disaster prevention sensor that detects smoke, intrusion, etc. from changes.

[Prior Art] This type of detector includes scattered light type smoke detectors and dimming type smoke detectors in fire alarm equipment, and radio wave type or ultrasonic type intrusion detectors in burglar alarm equipment. These sensors operate the emission source intermittently to prevent malfunctions due to the incidence of external noise or to reduce power consumption due to emission, and detect when a detection output is generated that coincides with the emission. Most sensors use a so-called synchronous detection method, which detects signals.

[Problems to be Solved by the Invention] However, even if a sensor using the synchronous detection method as described above is used, if external noise is frequently incident, the external noise may not reach the detection unit when it is emitted. This often caused malfunctions.

[Means for Solving the Problems] Therefore, the disaster prevention sensor according to the present invention detects that the detection output at the time of release from the release source exceeds a predetermined value, and detects when the release source does not release. The above-mentioned problem has been solved by generating a sensing signal only when the detection outputs of the detection sections in both do not exceed a predetermined value.

[Function] Since the disaster prevention sensor according to the present invention has the above-described configuration, the detection output is sampled before and after the release, and
When at least one of the detection outputs before and after the release is generated, no sensing signal is generated even if the detection output is generated during the release.

[Example] Fig. 1 is a circuit diagram when the disaster prevention sensor according to the present invention is applied to a scattered light type smoke sensor in a fire alarm system, and a light source 1 is used as the emission source. This light source 1 consists of two pulse generators Sl and S2 with different oscillation periods.
It is driven by the output from a timing pulse generator P consisting of AND circuits 2 to 5 and one counter 6. Light from the light source 1 is scattered by smoke and enters a light receiver 7 as a detection section. The output of the photoreceiver 7 is sent to an amplifier 8.
After being amplified by , the signal is input to two comparators 9.10. Of these two comparators 9 and 10, the first comparator 9 is set to a level slightly higher than the smoke detection level as a predetermined comparison value, and the second comparator 10 is set to the smoke detection level as a comparison predetermined value. . The output of the first comparator 9 is connected to the first comparator 9 via an inverter. Third D-type flip-flop circuit 11
It is connected to the D terminal of ゜13. The output of the second comparator 10 is the D of the D-type flip-flop circuit 12 of the tube 2.
connected to the terminal. The C terminals of these three D-type flip-flop circuits 11 to 13 are connected to the input terminal of an AND circuit 14, and the output of the AND circuit 14 is used as a sensing signal. The Q4 terminal of the counter 6 is connected to the R terminals of the three D-type flip-flop circuits 11 to 13, and the QI of the counter 6 is connected to each C terminal.
The output terminals of AND circuits 3 to 5 which take the logical product of the Q2 and Q3 terminal outputs and the C terminal input are connected. However, the output of the AND circuit 4 is connected to the C terminal of the second D-type flip-flop circuit 12 via a NOT circuit. Note that the output of the Q4 terminal is connected to the R terminal of the counter 6 via an integrating circuit.

The operation of the scattered light type smoke detector to which the disaster prevention sensor according to the present invention configured as described above is applied will be explained based on the signal waveform diagram of each part in FIG. 2.

Two pulse generators Sl of timing pulse generator P
, S2 output pulses with different frequencies and duty ratios shown by waveforms S1 and S2, and these two pulses are combined by an AND circuit 2 to produce four consecutive pulses as shown by waveform a. It is converted into intermittent pulses consisting of a pulse group PG. This intermittent pulse is input to the C terminal of the counter 6, and the Q
Each AND circuit 3 connected to the l, Q2 and Q3 terminal sides
~5 is also input.

As a result, each AND circuit 3 to 5 outputs waveforms S, c,
A signal as shown in e is output. The light source 1 generates a waveform C corresponding to the second pulse signal in this pulse group PG.
It is lit intermittently by the signal shown in .

On the other hand, the output signals from the amplifier 8 connected to the light receiving side 2; 7 are compared with respective comparison predetermined values, and both comparisons 39 and 10 generate outputs as shown in waveforms f and g, respectively. Each of the flip-flop circuits 11 to 13 takes in this output signal in synchronization with each pulse timing from the timing pulse generator P, and outputs outputs as shown in waveforms h to j, respectively. The AND circuit 14 performs a logical product of these output signals, and its output is used as a sensing signal.

Therefore, no external noise enters the light receiver 7,
During normal detection as shown in section I where light scattered by smoke is not incident, outputs are generated from all D-type flip-flop circuits 11 to 13 in synchronization with each pulse timing, so the AND circuit i1'M 14 outputs a sensing signal.

However, in the case shown in section H where external noise frequently enters the light receiver 7, the first . Third D-type flip-flop circuit 1
1.13, so even if the second D-type flip-flop circuit 12 generates an output, the AND circuit 14 will not output a sensing signal.

The processing up to this point is performed using the previous three pulses in each pulse group PG. Then, M in each pulse group PG
The counter 6 and the first to third D
Type flip-flop circuits 11-13 are reset. In this way, one process is completed for each pulse group PC.

Note that the predetermined comparison value of the first comparator 9 is set to a level slightly higher than the smoke detection level, but this is to prevent external noise from interfering with the actual smoke detection.

In the above example, the present invention is applied to a scattered light type smoke detector as a sensor, but it goes without saying that it can be similarly applied to other sensors.

[Effects of the Invention] As described above, the disaster prevention sensor according to the present invention can detect when the detection output of the emission source exceeds a predetermined value, and can also detect before and after the emission when the emission source is not emitting. Since a sensing signal is generated only when the detection outputs of both parts do not exceed a predetermined value, it is possible to reliably obtain a sensing signal even in an environment where external noise frequently arrives. , will not malfunction.

[Brief explanation of the drawing]

Figure 1 is a circuit diagram when the disaster prevention sensor according to the present invention is applied to a scattered light type smoke detector in fire alarm equipment;
The figure is a signal waveform diagram of each part in the circuit of FIG. 1. 1... Emission source (light source), 7... Detection section (light receiver),
Sl, S2...Pulse generator, 6...Counter, 9
゜10... Comparator, 11-13... D type flip.
flop circuit

Claims (2)

[Claims] (1) A emission source that intermittently emits light, radio waves, sound waves, etc., and a detection section into which the above emission enters directly or indirectly are provided, and smoke, intruders, etc. are detected by changes in the amount of incidence on the detection section. In the disaster prevention sensor that detects the presence of a target to be detected, the detection unit detects that the detection output of the emission source exceeds a predetermined value, and before and after the emission when there is no emission from the emission source. A disaster prevention sensor characterized in that a sensing signal is generated only when the detection outputs of both do not exceed a predetermined value. (2) The disaster prevention sensor according to claim 1, wherein the light source is the emission source and the light receiver is the detection section.