JPH09128665A - Detector - Google Patents

Abstract

(57) [Abstract] [Problem] In a detector for detecting environmental changes,
At the same time as improving the processing capacity, the current consumption is reduced. A switching means 3 switches control of a detection means 4 to a first control means 2 side in a normal state where an environmental change is not detected, and when the detection means detects an environmental change, the switching means 3 controls the detection means. Switch to the second control means 1 side. As a result, it is possible to extend the life of the battery 6 of the power source by using the first control means which has low accuracy but low power consumption. Further, as the second control means, one having a large processing current and a high processing capacity is used.
The detection accuracy can be improved.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a detector for detecting environmental changes. This detector is used, for example, as a photoelectric smoke detector that detects smoke as a change in environment and sends a warning signal of a fire occurrence.

[0002]

2. Description of the Related Art A photoelectric smoke detector is installed in a building, a house or the like, and when a fire occurs, it detects smoke generated by the fire and sends an alarm signal. The photoelectric smoke detector has a light emitting element and a light receiving element, and is arranged in such a relationship that the light emitting element does not receive the light emitted by the light emitting element in a normal state.
When smoke is generated due to fire or the like, the light emitted from the light emitting element is scattered by the smoke, and a part of the light is received by the light receiving element. The output of the light receiving element is signal-processed and sent as an alarm signal to the outside.

Constantly emitting light from the light emitting element increases current consumption. Therefore, in the conventional photoelectric smoke detector,
The light emitting element is caused to emit light in a cycle of several seconds to 10 seconds to reduce current consumption. Since the light emitting element emits light intermittently in this manner, when the light receiving element detects the light received for a short time once, an alarm signal is sent out. Therefore, the photoelectric smoke detector is used for external noise, flash, sunlight, etc. Malfunctions are likely to occur due to the influence of ambient light.

In order to prevent this malfunction, photoelectric smoke detectors have been put into practical use in which a light-receiving element sends an alarm signal only when it detects light continuously a predetermined number of times. This photoelectric smoke detector is called a storage type photoelectric smoke detector. In recent years, as the accumulation type photoelectric smoke detectors, those using a CPU or the like for increasing the signal processing capability have been increasing. This is to improve the smoke detection accuracy by using the CPU to make the light-emission period of the light-emitting element accurate, particularly during the accumulation process.

Before using the CPU, the light emitting period of the light emitting element was controlled by using a CR oscillator or the like. The CR oscillator outputs a signal at a predetermined cycle determined by the capacitor and the resistor. An error occurs in the cycle of the output signal of the CR oscillator due to the manufacturing error and temperature characteristics of the capacitor and the resistor. In particular, during the storage process, it is necessary to control the light emission interval accurately in order to judge the fire, but this error may cause variations in the light emission intensity and the light emission cycle of the light emitting element, and it may not be possible to accurately judge the fire. is there. Further, if the cycle is delayed due to an error, there is a problem that it takes time to output the alarm signal.

In order to improve the accuracy of this CR oscillator,
The cost of the photoelectric smoke detector increases because a capacitor with a small capacitance error must be used and the manufactured capacitor and resistor must be tested and sorted. On the other hand, if the CPU always controls the light emission interval, the signal can be repeatedly output in an accurate cycle, so that the light emitting element can emit light in a highly accurate cycle. However, the CPU consumes a current of several mA when the program is executed. This current value is much larger than the current consumption of a conventional detection device using a CR oscillator or the like. In the following description, the state in which the CPU is executing the program will be referred to as the “operating state”.

[0007]

In the above-described conventional detector using a CPU or the like, the detection accuracy of the environmental change is improved, but the current consumption is increased. Therefore, when using a battery as a power source, a large capacity battery must be used. It is an object of the present invention to improve processing capacity and reduce current consumption in a detector for detecting environmental changes.

[0008]

In order to achieve the above object, the present invention comprises a detecting means for detecting an environmental change, a first controlling means for operating the detecting means at a predetermined cycle, and a detecting means. The control signal is changed from the standby state to the operating state by the second detection signal, and the second control means for operating the detection means in a predetermined cycle, and the detection means are switched to the control by the first control means or the control by the second control means. A detector is composed of the switching means.

The switching means switches the detection means to the control by the first control means in a normal state where no environmental change is detected. When the detecting means detects the environmental change, the switching means switches the detecting means to the control by the second control means. As a result, the second control means operates only when the environmental change is detected. Therefore, it is possible to use, as the second control means, one having high processing capability even if the current consumption is large.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION An example in which the present invention is applied to a storage type photoelectric smoke detector will be described below with reference to FIGS.
FIG. 1 is a block diagram showing the configuration of a storage type photoelectric smoke detector according to the present invention.

The photoelectric smoke detector has a photoelectric module 4 which detects the presence or absence of smoke and outputs an electric signal. The photoelectric module 4 has a light emitting element 41 that emits light when an electric signal is input and a light receiving element 42 that outputs an electric signal when light is received. The relationship between the light emitting element 41 and the light receiving element 42 is that the light emitting element 41 does not normally receive the light emitted by the light emitting element 41, but when smoke is generated, the light emitted from the light emitting element 41 is scattered by the smoke and Part of the light receiving element 42
The light is received by.

A switching unit 3 for switching control of the light emitting element 41 to the CR oscillating unit 2 side or the signal processing unit 1 side is provided. The switching unit 3 normally supplies the electric signal from the CR oscillating unit 2 to the light emitting element 41, but when receiving the control signal from the signal processing unit 1, supplies the electric signal from the signal processing unit 1 to the light emitting device 41. Switch to do. The output signal of the light receiving element 42 is input to the signal processing unit 1.

The CR oscillator 2 outputs an electric signal for causing the light emitting element 41 to emit light at a predetermined cycle determined by the capacitor and the resistor. The signal processing unit 1 includes a CPU and peripheral circuits. The signal processing unit 1 normally maintains the sleep state, but becomes active when receiving a signal from the light receiving element 42. The CPU used in the signal processing unit 1
Consumes about several μA in the sleep state, which is much smaller than several mA in the operating state.

When the signal processing unit 1 is activated, it outputs to the switching unit 3 a signal for switching the control of the light emitting element 41 to the signal processing unit 1 side and a signal for causing the light emitting element 41 to emit light at an accurate predetermined cycle. . In addition, the signal processing unit 1 includes the light receiving element 4
The signal from 2 is processed to determine whether or not smoke is detected. When it is determined that smoke is detected, the output unit 5 outputs an alarm signal.

A battery power source 6 is provided as a common power source for the above-mentioned parts. Next, the operation of the photoelectric smoke detector will be described with reference to the time chart of FIG.
In FIG. 2, (A) shows a signal output from the CR oscillation unit 2, (B) shows an operation state of the signal processing unit 1,
(C) shows a light emitting state of the light emitting element 41, (D) shows a light receiving state of the light receiving element, and (E) shows an abnormal signal output state of the output section 5. Also, no smoke was detected until time a,
It is assumed that smoke is detected during the time points b to e and no smoke is detected after the time point f.

The CR oscillator 2 outputs a signal for causing the light emitting element 41 to emit light at a predetermined cycle T ± t. Here, the cycle T ±
T of t is a predetermined cycle required as the light emission interval of the light emitting element 41, and t is an error time. This error time t occurs due to manufacturing error and temperature characteristics of the capacitors and resistors that are the components of the CR oscillation unit 2, and the CR oscillation unit 2
Shows different values.

As described above, the switching unit 3 controls the control of the light emitting element 41 at the normal time (timing a) when there is no smoke.
Since it is switched to the oscillation unit 2 side, the light emitting element 41 repeats light emission at the cycle T ± t. In the absence of smoke, light is not scattered by smoke, so the light receiving element 42 does not receive the light emitted by the light emitting element 41 and does not output a signal to the signal processing unit 1. Therefore, the signal processing unit 1 is in the sleep state and does not output a signal to the switching unit 3 or the output unit 5.

When smoke is generated due to a fire or the like (timing b), the light emitted from the light emitting element 41 is scattered by the smoke, so that the light receiving element 42 receives a part of the light and outputs a signal to the signal processing section 1. To do. In FIG. 2, it is assumed that the light receiving section 42 receives light almost at the same time as the light emitting section 41 emits light. As a result, the signal processing unit 1 is activated almost at the same time as the light reception, and at the same time when the signal processing is started,
A switching signal and a signal for causing the light emitting element 41 to emit light at a predetermined cycle T are output.

The switching unit 3 switches control of the light emitting element 41 to the signal processing unit 1 side. The signal output from the signal processing unit 1 for causing the light emitting element 41 to emit light is transmitted in a cycle T with an extremely small error. Therefore, the light emitting element 41 comes to emit light in the cycle T with high accuracy. Signal processing unit 1
Starts counting the number of signals output from the light receiving element 42, that is, the number of smoke detections. In this example, when smoke is detected three times in succession (timing b, c and d), the signal processing unit 1 outputs an abnormal signal from the output unit 5 at substantially the same time as the light reception at timing d (not shown). Etc. to send.
After that, while smoke is being detected (timings d to e), the abnormal signal is continuously output from the output unit 5.

When the smoke disappears (timing f),
The light receiving element 42 no longer detects the light emitted from the light emitting element 41, and stops sending the signal to the signal processing unit 1. When the signal processing unit 1 stops receiving the signal from the light receiving element 42,
The output of the abnormal signal from the output unit 5 is stopped, the smoke detection count is cleared, and the switching unit 3 is operated to switch the control of the light emitting element 41 to the CR oscillation unit 2 side. Furthermore, the state of the signal processing unit 1 is returned from the operating state to the sleeve state.

After that, the light emitting element 41 is blinked at the cycle T + t by the CR oscillating section 2 which consumes less current, and the smoke detecting operation is continued. As described above, the photoelectric smoke detector of this example controls the light emitting element by CR when the smoke is not detected.
When the oscillating section 2 is used and smoke is detected, the light emitting element is controlled by the signal processing section 1 using a CPU.

In the photoelectric smoke detector, smoke is not detected for a long time. In this example, since the CR oscillator 2 that consumes less current is used in this state, the life of the battery can be extended even when a battery is used as the power source, and the running cost of the fire monitoring system can be reduced. . On the other hand, when smoke is detected, the smoke detection cycle can be made highly accurate by the control of the CPU, and the reliability of the photoelectric smoke detector can be improved.

Further, since the CR oscillating section 2 for controlling the light emitting element at a normal time is not required to have strict accuracy,
It is not necessary to select parts for the capacitors to be used, and the manufacturing cost can be reduced. In addition,
In this example, the control of the light emitting element 41 is normally performed by the CR oscillating unit 2.
However, various means can be used in place of the CR oscillating section as long as it is a means for generating a predetermined cycle with low current consumption.

[0024]

According to the present invention, in a detector for detecting environmental changes, the processing capability is improved and at the same time,
It is possible to reduce current consumption.

[Brief description of the drawings]

FIG. 1 is a block diagram showing an embodiment of a detector of the present invention.

FIG. 2 is a time chart for explaining the operation of the detector of FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Signal processing part 2 ... CR oscillation part 3 ... Switching part 4 ... Photoelectric module 41 ... Light emitting element 42 ... Light receiving element 5 ... Output part 6 ... Battery power supply

Claims (1)

[Claims] 1. A detection means for detecting an environmental change, and a first control means for operating the detection means in a predetermined cycle,
A second control unit that shifts from a standby state to an operating state according to a detection signal from the detection unit and operates the detection unit at a predetermined cycle, and the detection unit is controlled by the first control unit or the first control unit. A detector characterized by having switching means for switching to control by the second control means.