JP2004062299A - Smoke sensor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a smoke sensor which can reduce false reporting of fire due to noise and incorrect restoration as much as possible. <P>SOLUTION: In the smoke sensor, smoke density data are compared with a fire judgement level whenever the data are sampled at a prescribed period. When the sampled smoke density data are more than the fire judgment level as a result of comparison, a count-up operation is performed. When it does not exceed the fire judgment level, a count-down operation is performed. A value of an up/down counter 4 reaches a maximum value or a minimum value which is previously set, fire reporting or fire restoration is preformed. In the up/down counter 4, count width at the time of the count-up operation or count width at the time of count-down is variably set. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
According to the present invention, each time the smoke density data is sampled and compared with a preset fire judgment level value, an up / down counter is counted, and a fire alarm or fire recovery is performed based on the counting result. Related to smoke detectors.
[0002]
[Prior art]
2. Description of the Related Art There is known a smoke detector that uses a storage operation of an up / down counter to prevent a false alarm due to a short-time data change such as noise.
[0003]
FIG. 6 is a block diagram showing a main part configuration of this type of conventional smoke detector.
[0004]
Conventional smoke detectors of this type include a smoke density detection unit that detects the density of smoke generated by a fire, a smoke density data measurement unit that converts the detected smoke density into a voltage value, and smoke density data that has been measured. A fire judging unit is provided for comparing a fire judgment level value and counting up or down an up / down counter based on the result to judge whether a fire has been issued or fire has been recovered.
[0005]
FIG. 7 shows the basic operation of the up / down counter.
[0006]
The fire determination unit samples the smoke density data at a predetermined cycle, and if the smoke density data ≧ the fire determination level value, increments the counter by one, and if the smoke density data <the fire determination level value, decrements the counter by one.
If the counter value reaches the maximum value (5) when the fire is not being fired, and if the counter value becomes the minimum value (0) while the fire is being fired, it is determined that the fire has been recovered.
[0007]
FIG. 8 is a graph showing the time course of the smoke density data.
[0008]
When the smoke density data is sampled, if the sampling value is equal to or greater than a predetermined fire judgment level value, a count-up operation is performed, "1" is added, and if the sampling value is smaller than the predetermined fire judgment level, The countdown operation is performed, and “1” is subtracted. When the count value reaches a fire alarm level, that is, a maximum value (for example, “5”), a fire alarm is issued. When the value reaches a value (for example, “0”), the fire is restored.
[0009]
After the count value reaches the fire alarm level, the count value retains the maximum value even if the sampling value exceeds the fire discrimination level, and after the count value reaches the fire recovery level, the sample value decreases. Even if it becomes smaller than the fire determination level, the count value keeps the minimum value.
[0010]
In this way, if an up-down counter is provided, a fire alarm is issued only when smoke density data ≧ fire judgment level value continues for a certain period of time, and a fire occurs only when smoke concentration data <fire judgment level value continues for a certain period of time. Since recovery is performed, it is possible to prevent a false alarm or a false recovery of a fire due to noise or the like, which instantaneously causes the smoke density data to fluctuate above and below the fire determination level value.
[0011]
[Problems to be solved by the invention]
However, this type of conventional smoke detector has the following problems.
[0012]
FIG. 9 is a time series graph showing the relationship between the occurrence of noise and the counter value in the normal monitoring (no fire alarm signal is output) state.
[0013]
As shown in the graph, when noise occurs continuously, one noise is completed, the smoke density data returns to the normal value, and immediately after that, the next noise may occur (see FIG. Arrow A). Then, before the counter value does not decrease to the minimum value “0” (in the example, “1”), the count-up starts, and in fact, only four counts from “2” to “5” are performed. Fire alarm.
[0014]
Further, as shown in FIG. 10, when continuous noise occurs in the output state of the fire alarm signal, the counter counts down due to the next noise before the counter is sufficiently raised (arrow B in the figure). Erroneous recovery due to the countdown of numbers.
[0015]
In general, since noise often occurs continuously, the up / down counter provided to prevent false alarms due to noise will malfunction as described above, and the sensor will falsely report and erroneously recover. There was trouble.
[0016]
Further, such a trouble cannot be solved only by adjusting the maximum value and the minimum value of the counter.
[0017]
The present invention has been proposed to solve such a problem, and an object of the present invention is to provide a smoke detector capable of minimizing erroneous fire alarms and erroneous recovery due to noise.
[0018]
[Means for Solving the Problems]
In order to solve the above-mentioned problem, the smoke detector according to claim 1 compares the smoke density data with a fire determination level every time the smoke density data is sampled at regular intervals. The count-up operation of the up / down counter is performed when the value is equal to or higher than the judgment level, and the countdown operation is performed when the value does not exceed the fire judgment level. When the value of the up / down counter reaches a preset maximum value or minimum value, a fire alarm is issued. Alternatively, the up-down counter is a smoke detector that performs fire recovery, and the up-down counter can variably set at least one of a count width during a count-up operation and a count width during a count-down operation.
[0019]
That is, the up-down counter can execute the counting operation by making the up width different from the down width. For example, if the up width is set smaller than the down width, the counter becomes the maximum value due to noise having a long noise width. The up-down counter according to claim 2, wherein when the fire alarm signal is not output, the up-down counter can be prevented from erroneous fire judgment due to such malfunction of the counter. Count up and down by using the and the down width, and when the fire alarm signal is output, count up and down by using the up width and the down width at the time of the fire alarm. .
[0020]
In other words, the count width can be made different between the state in which the fire alarm signal is not output and the state in which the fire alarm signal is output, and count-up and count-down can be performed.
[0021]
According to a third aspect, in the second aspect, the down width at the time of the normal monitoring is made larger than the up width at the time of the normal monitoring.
[0022]
In other words, if the down width during normal monitoring is larger than the up width, it is unlikely that the counter will fall to the minimum value even if the interval between noises is short, and fire alarm due to erroneous counting will be reduced. Can be.
[0023]
According to a fourth aspect, in the second or third aspect, the down width at the time of fire alarm is smaller than the down width at the time of normal monitoring.
[0024]
In other words, if the down width at the time of a fire alarm is made smaller than the down width at the time of normal monitoring, it is possible to reduce the possibility that the counter reaches the minimum value due to the noise itself during the fire alarm, thereby preventing erroneous recovery due to the noise. Can be prevented.
[0025]
According to a fifth aspect of the present invention, there is further provided a setting means for variably setting the up width and the down width, thereby making it possible to adjust the count width to the nature of the noise.
[0026]
According to claim 6, the setting means can further change the setting of the maximum value and the minimum value in addition to the up width and the down width.
[0027]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.
[0028]
FIG. 1 is a block diagram showing a main configuration of a smoke detector according to the present invention.
[0029]
The smoke detector includes a smoke density detection unit 1 for detecting the density of smoke generated by a fire, a smoke density data measurement unit 2 for converting the detected smoke density into a voltage value, a measured smoke density data and a fire determination level. The value is compared with the value, and the up / down counter 4 counts up or down based on the result, and a fire judging unit 3 for judging a fire alarm or a fire recovery, and a setting capable of variably setting the up width and the down width of the counter. Means 5.
[0030]
The fire determination unit samples the smoke density data at a predetermined cycle, and increases the counter when smoke density data ≧ fire determination level value, and decreases the counter when smoke density data <fire determination level value,
If the counter value reaches the maximum value (5) when the fire is not being fired, and if the counter value becomes the minimum value (0) while the fire is being fired, it is determined that the fire has been recovered.
[0031]
In this respect, the operation is the same as that of the conventional up / down counter of the smoke detector, but in the present invention, the up / down counter 4 can be variably set by the setting unit 5 so that the count width is made different. Have to be able to.
[0032]
Specifically, as shown in FIG. 2, the up width and the down width in the normal monitoring (no fire alarm signal is output) state may be set to be different (FIG. 2 (a)). The down width in the normal monitoring state and the down width in the fire alerting state may be set differently (FIG. 2B) or a combination of the above (FIG. 2C).
[0033]
In the following, the counter for the case of FIG. 2C in which the down width at the time of normal monitoring is set to a value larger than the up width and the down width at the time of fire alarm is set to a value smaller than the down width at the time of normal monitoring. A description will be given of the operation and the logic of prevention of false alarms and prevention of false recovery.
[0034]
FIG. 3 is a diagram showing an operation example of the up / down counter.
[0035]
(A) shows a count-up operation, in which the count is incremented by one and a fire alarm is generated when the counter reaches the maximum value "5" in a state where the fire alarm signal is not output. ing.
[0036]
FIG. 2B shows a countdown operation in the normal monitoring state. For example, if the smoke density data falls below the fire determination level value when the counter is “4”, the countdown is performed by 2 in accordance with the table of FIG. If the value exceeds the fire judgment level value, the count is incremented by one.
[0037]
FIG. 2C shows a countdown operation in the fire alert state. For example, if the smoke density data falls below the fire determination level value when the counter is "1", the count value is set to 0.5 according to the table in FIG. Counts down by one, and when the minimum value becomes "0", the fire is recovered. If the fire determination level value or more is continued, the count is incremented by one.
[0038]
FIG. 4 is a time series graph showing the relationship between the occurrence of noise during normal monitoring and the counter value.
[0039]
As shown in the graph, when the smoke density data returns to the normal value lower than the fire determination level value after one noise is generated, the smoke density data is reduced by two (in the example, “3” → “1” → “0”). 4) Since the countdown is performed, even if the next noise may occur immediately thereafter (arrow A in the figure), the counter value is not counted up from a value larger than “0”. As a result, FIG. As long as the noise is generated as described above, false alarm can be prevented.
[0040]
To make the down width larger than the up width means to make the up width smaller. For example, if the up width is set to “0.5” for the down width “1” at the time of normal monitoring, The counter is unlikely to reach the maximum value due to noise, and the same effect can be obtained.
[0041]
In this case, the down width at the time of the normal monitoring can be set by the setting unit 5, so that the setting may be appropriately adjusted according to the nature of the generated noise. For example, if the interval between noises is statistically shorter than that shown in FIG. 4, it is difficult to reach the minimum value “0” by the countdown, so that the down width is set to “2.5”, “3”. "Or the like. Of course, the up width may be set and changed.
[0042]
FIG. 5 is a time series graph showing the relationship between the occurrence of noise at the time of fire alarm and the counter value.
[0043]
As shown in the graph, when one noise is generated during the fire alert and the smoke density data returns to the fire judgment level value or more, the next noise is generated immediately after that, and 0.5 ( In the example shown in the figure, “4” → “3.5” → “3” → “2.5” → “2”) Even if the countdown is performed, the count does not reach “0”, so that it is not determined that the data is recovered erroneously ( Arrow B) in the figure.
[0044]
In this case, the down width at the time of the fire alarm can be set by the setting unit 5, so that the setting may be appropriately adjusted according to the nature of the generated noise. For example, if the width of the noise itself is statistically longer than that shown in FIG. 5, the minimum width is more likely to reach “0”, so the down width is set to “0.3”, “0.2”, etc. Should be set to.
[0045]
The setting change of the count width by the setting means 5 can be performed for each of the up width and the down width at the time of normal monitoring, and the up width and the down width at the time of a fire alarm. May be variably set.
[0046]
Further, in addition to the change of the count width, the maximum value and the minimum value may be variably set, so that more fine adjustment may be performed.
[0047]
【The invention's effect】
As can be understood from the above description, in the smoke detector according to the first aspect, either the up width or the down width of the up / down counter can be variably set, so that the count width is made different. Thereby, it is possible to effectively prevent erroneous alarm and erroneous recovery due to noise, and to obtain a smoke detector having high noise resistance.
[0048]
In particular, according to the second aspect, the count width can be made different between the state in which the fire alarm signal is not output and the state in which the fire alarm signal is output, and the count can be counted up or down. Can be finely adjusted.
[0049]
According to the third aspect, the down width at the time of normal monitoring is made larger than the up width, so that even if the interval between the noises is short, the counter is unlikely to fall down to the minimum value, and the counter operates abnormally. Erroneous alerts can be prevented. Conversely, if the up width is smaller than the down width, the counter itself rarely reaches the maximum value due to the noise itself, and the same effect can be obtained.
[0050]
According to the fourth aspect, the down width at the time of fire alarm is made smaller than the down width at the time of normal monitoring, so that the counter does not reach the minimum value due to the noise itself during the fire alarm. Erroneous recovery due to abnormal operation can be prevented.
[0051]
According to the fifth aspect, the up width and the down width can be set and changed by the setting means. Therefore, if the generated noise is examined statistically, it is possible to easily adjust the count width to the noise. In particular, if the up width and down width during normal monitoring and the up width and down width at the time of fire alarm can be set, a smoke detector with higher noise resistance can be obtained.
[0052]
According to claim 6, since the maximum value and the minimum value are also variably set, further fine adjustment can be performed.
[Brief description of the drawings]
FIG. 1 is a block diagram showing a main configuration of a smoke detector according to the present invention.
FIG. 2 is a diagram illustrating an example of a setting mode of an up width and a down width.
FIG. 3 is a diagram illustrating an operation example of an up-down counter.
FIG. 4 is a time-series graph showing a relationship between noise occurrence and a counter value during normal monitoring.
FIG. 5 is a time-series graph showing a relationship between noise occurrence and a counter value at the time of fire alarm.
FIG. 6 is a block diagram showing a main configuration of a conventional smoke detector using an up / down counter.
FIG. 7 is a diagram showing a basic operation of a conventional up / down counter.
FIG. 8 is a graph showing the time course of smoke density data.
FIG. 9 is a time-series graph showing a relationship between noise generation and a counter value during normal monitoring in a conventional smoke sensor.
FIG. 10 is a time-series graph showing a relationship between a noise occurrence and a counter value at the time of a fire alarm in a conventional smoke detector.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Smoke density detection part 2 ... Smoke density data measurement part 3 ... Fire determination part 4 ... Up / down counter 5 ... Setting means

Claims (6)

Each time the smoke density data is sampled at regular intervals, it is compared with the fire judgment level, and as a result of the comparison, if the sampled smoke density data is higher than the fire judgment level, the up / down counter counts up and the fire judgment level is set. When it does not exceed, the countdown operation is performed, and when the value of the up / down counter reaches a preset maximum value or minimum value, the smoke detector performs a fire alarm or fire recovery,
The up / down counter is
A smoke detector characterized in that at least one of a count width at the time of a count-up operation and a count width at the time of a count-down can be variably set. In claim 1,
The up-down counter counts up and down using the up width and down width at the time of normal monitoring when the fire alarm signal is not output, and when the fire alarm signal is output, A smoke detector which counts up and down using the up width and the down width at the time of a fire alarm. In claim 2,
A smoke detector characterized in that the down width during normal monitoring is larger than the up width during normal monitoring. In claim 2 or 3,
A smoke detector characterized in that the down width at the time of a fire alarm is smaller than the down width at the time of normal monitoring. In any one of claims 1 to 4,
A smoke detector further comprising setting means for independently and variably setting the up width and the down width. In claim 5,
The smoke detector, wherein the setting means further enables setting change of the maximum value and the minimum value.

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