JP2583271B2 - Fire alarm - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a fire alarm device for judging a fire abnormality based on a physical quantity such as heat, smoke, or gas, and particularly when detecting a sign of the abnormality. Start or trigger,
The present invention relates to a fire alarm device that starts a fire determination routine for fire determination, such as arithmetic processing such as integration, differentiation, or difference, or pattern determination.

[Prior Art and Problems] For example, a digitized analog quantity signal of a physical quantity output by a fire phenomenon detection means is processed by arithmetic processing such as integration, differentiation or difference, or pattern determination to determine fire. It is thought to do.

If you always run such a fire detection routine,
There are problems such as an increase in current consumption, an increase in time required for determination processing, and a delay in other processing.

For this reason, the fire discrimination routine is normally set to a rest state, and when the analog amount signal, that is, the sensor output level exceeds a predetermined level, the fire discrimination routine is triggered,
It is conceivable to execute fire determination such as arithmetic processing. In this case, fluctuations in environmental noise components such as temperature, humidity, dust, light, or a volatile liquid (a gas component is generated by paint or the like) (for example, general (Specifically, the temperature and the amount of dust in the air are high during the day and low during the night), or the difference between the level of the analog amount signal and the predetermined level is not constant due to contamination or deterioration of the detection element such as the light receiving element. It always fluctuates, so that an error occurs in the result of the fire determination, which causes a problem that a correct fire determination cannot be made.

Therefore, according to the specification of the patent filed on March 22, 1988, filed by the present applicant, the environment changes from normal to abnormal due to the temporal gradient of the physical quantity, that is, the analog quantity signal level. By detecting a state, that is, a state showing a sign of abnormality, and triggering or starting with a fire determination routine when the inclination exceeds a predetermined inclination, the influence of environmental noise, element contamination, deterioration, etc. There is provided a fire alarm device which does not receive the fire.

In a fire alarm device as disclosed in the patent application, for example, a physical quantity detected due to a low resolution of an analog / digital converter provided in a fire phenomenon detecting means for detecting a physical quantity and outputting a sensor output level. In the case where the resolution of the sensor output level corresponding to is low, it is very difficult to accurately determine the slope. In particular, since the physical quantity rises very slowly in the early stage of the fire, it is difficult to determine the slope at the sensor output level, and there is almost no change in the sensor output level between several samplings. In spite of the fact that the slope of the actual physical quantity has risen in the early stage of the fire, the slope of the sensor output level is hardly observed, so that triggering the fire determination routine is delayed, and as a result, the fire in the initial state There is a risk that the detection will be delayed and the fire will spread.

Means for Solving the Problems The present invention has been made in view of the above points, and even when the resolution of the sensor output level output by the fire phenomenon detection means is low, a fire in an initial state is detected early. It is an object of the present invention to provide a fire alarm device capable of performing such operations.

Therefore, according to the present invention, the storage means for storing the latest plurality of sensor output levels up to the present time of the physical quantity of the fire phenomenon sampled by the fire phenomenon detection means, and a certain memory stored in the storage means Change determining means for determining whether or not the change tendency between the sensor output level at the time and the sensor output level at the present time exceeds a predetermined limit; and the change tendency of the sensor output level exceeding the predetermined limit. When the determination is made, the data processing of the fire determination based on the sensor output level is started retroactively up to the certain point in time of the plurality of sensor output levels stored in the storage means. A fire discriminating means for performing based on a sensor output level newly sampled by the means. It is subjected.

[Operation] A sensor output level for a certain period of time from the past to the present time is stored in the storage means, and a difference or a slope between the sensor output level at a certain point in time and the sensor output level at the present time is stored. If the change trend exceeds a predetermined limit, a trigger is performed retroactively to that point in time. Then, while performing data processing by the fire determination routine from the trigger point to the present time,
Further, after the present time, following the data processing by the fire determination routine performed up to the present time, a similar fire determination routine is continuously performed in accordance with the sampling cycle by the fire phenomenon detecting means.

[Example] An example of the present invention will be described below.

FIG. 1 shows an embodiment in which the present invention is applied to an optical smoke detector. In the drawing, RE is a receiver, DE is a plurality of sensors connected to the receiver RE, FIG. 1 shows only one of them. L _{1 to} Ln are, for example, a pair of power / signal lines to which a plurality of sensors DE are connected, respectively.

In the sensor DE, the MPU is a microprocessor, the ROM 1 is a first program storage area for storing a program whose example is shown in a flowchart in FIGS. 2A to 2C, and the ROM 2 stores another program. RAM1 is a storage area for storing a plurality of sensor output levels SLV from the fire event detection means FS, RAM2 is a work area, and FS is a fire event detection means. Yes, an optical smoke detector is shown as an example. In the fire phenomenon detecting means FS, LED is a light emitting element such as a light emitting diode, DR is a light emitting circuit for causing the light emitting diode LED to emit light at predetermined time intervals, for example, and SB is, for example, light smoke emitted from the light emitting diode LED. A light receiving element such as a solar cell, which receives scattered light, AM is an amplifier, and SH is an amplifier AM synchronized with light emission of a light emitting diode LED.
AD is an analog-to-digital converter that converts the analog signal from the sample-and-hold circuit SH into a digital analog quantity signal as a sensor output level. TRX is a fire signal sending unit. , IF1 and IF2 are interfaces.

The operation of FIG. 1 will be described with reference to the flowcharts of FIGS. 2A to 2C.

In order to read the sensor output level SLV, the light emitting circuit DR is driven at predetermined time intervals, for example, every two seconds, and
When the scattered light emitted from the light emitting element LED and scattered by the smoke is received by the solar cell SB, the solar cell SB generates an electric signal corresponding to the received light. Sample and hold circuit through amplifier AM
SH, where it is held at predetermined time intervals. The signal held in the sampling and holding circuit SH is converted into a digital analog signal by the analog-to-digital converter AD, and is output to the interface IF1 as a detection output level in the fire phenomenon detection means FS, that is, a sensor output level SLV.

Subsequent to the initial setting (step 201), when the sensor output level SLV is read into the work area RAM2 at predetermined time intervals from the fire event detecting means FS via the interface IF1 in this way (step 202). The read sensor output level is stored in the sensor output level storage area.
It is also stored in the RAM 1 (step 203). At that time, the oldest data is discarded.

A sensor output level storage area RAM1 is shown in FIG. 3 and contains N data, i.e., sensor output level storage locations. The latest data, that is, the sensor output level is stored at the top of the storage area RAM1, and the data stored up to that point is sequentially 1
Data is shifted downward one after another, and the data at the end, that is, at the bottom is discarded. In this way, the latest N data are always stored.

FIG. 4 graphically displays N sensor output levels stored in the sensor output level storage area RAM1, the vertical axis representing the sensor output level SLV, and the horizontal axis representing the time t. Have been. Each point on the graph corresponds to the sensor output level stored in each storage location in RAM1, in which case the sensor output level at point A is the oldest data in the lowest storage location in RAM1. The sensor output level at point C is RA
It corresponds to the one stored as the newest data at the highest level in M1. In FIG. 4, point A
Or from the minimum of the sensor output level LV ₁ at point B, and how has risen to the latest sensor output level LV _C is shown at point C. Note that points C and B in FIG.
And address of a storage location of a third diagram corresponding to A, respectively in FIG. 3 (C), (B) and are represented by (A), the address distance T _B between points C and B given that,
(B) = (C) a + T _B.

3 and 4, the sensor output level storage area is used.
In RAM1, it is assumed that a new sensor output level is fetched at a predetermined time interval equal to the sampling cycle of the fire phenomenon detection means FS and is constantly updated.
The update of the sensor output level in the RAM 1 may be performed not at every predetermined sample time interval of 2 seconds, but at a long time interval, for example, every 10 samples, that is, every 20 seconds.

In step 203, the latest sensor output level SLV is
When stored in the uppermost location of the sensor output level storage area RAM1, the next minimum value among the N sensor output levels stored in the sensor output level storage area RAM1,
That is the value shown as LV ₁ sought in Figure 4, it together is stored in the working area RAM2 as SLVmin, the minimum RAM1 to contain the most recent ones of the LV ₁ there are a plurality of The storage location, that is, the address (B) is similarly stored in the work area RAM2 (step 204).

When the address (B) and the minimum sensor output level SLVmin at the address (B) are stored in the work area RAM2, next, the address between the address (B) and the head storage location, that is, the address (C) distance T _B = _(B) -
(C) is obtained, the address distance T _B is work area RAM2
(Step 205). Then, based on the address distance T _B , the minimum value SLVmin, and the latest sensor output level SLV at the address (C), a gradient (SLV−SLVmin) / T _B with respect to the time between the points BC is obtained. Is stored in the work area RAM2 (step 206).

When the inclination K is stored in the work area RAM2, the inclination K
Is determined to be equal to or greater than a fixed value L of the slope to be triggered, and if not, the value is not equal to or greater than the fixed value L (N in step 207).
O), clear variables such as X in the fire determination routine 211 described later (step 208), and return to step 202 to read the next new sensor output level SLV.

In Steps 206 and 207, it is determined whether or not the slope between the two points is equal to or greater than a certain value L. A method of comparing with the difference is also possible.

If the slope K is equal to or more than the fixed value L (Y in step 207)
ES), a fire determination routine (step for tracking and monitoring the sensor output level to determine whether or not a fire is abnormal)
In this fire determination routine, first, based on the sensor output level stored in the RAM 1 from the address (B) to the current address (C), going back to the point B. It includes a part for performing the calculation and a part for performing the calculation based on the sensor output level read from the fire phenomenon detection means FS following the result of the calculation.

That is, when it is first determined that the slope K is equal to or larger than the constant value L, first, in step 204, the address (B) stored in the RAM 2 is set as a variable X (step 210).
In the fire determination routine (step 211), various calculations are performed based on the sensor output level stored at the address in the RAM 1 indicated by the X, and the calculation result does not indicate that there is a fire abnormality (NO in step 212). , And does not indicate that it is a pre-alarm (NO in step 213),
The value of X is decremented by one (step 215), and a similar fire determination routine is performed based on the sensor output level at the next address (B) -1 in the RAM 1 (step 21).
1). As described above, first, in a loop 211 to 215, a fire determination routine that goes back to the past of the address (B) is performed.

In this way, the value of X is decremented one by one, and the fire determination routine is performed. If the result of the calculation in the fire determination routine is not determined to be abnormal in step 212, X is determined.
If it is determined in step 214 that has been decremented to the value of the address (C) storing the current sensor output level (YES in step 214), the process returns to step 202 and returns to the next sampling time. The next new sensor output level is read and the contents of the RAM 1 are updated (step 203). If the slope K obtained in steps 204 to 206 is still equal to or greater than the constant value L (YES in step 207), then step 209 is performed. Is YES, that is, since X = (C), step 210 is skipped, and the fire determination routine (step 211) is performed based on the sensor output level within the address indicated by X = (C). go. In this case, since the contents of the RAM 1 have been updated in step 203, the address X
= The sensor output level in (C) is now a fire phenomenon detection means
New sensor output level just read from FS.

As described above, following the processing of the fire determination routine that goes back to the point B, processing subsequent to the present time in steps 202 to 214 is performed, and it is determined in step 207 that the slope K is equal to or greater than the fixed value L. If the result of the calculation in the fire determination routine is determined to be a pre-alarm, that is, a pre-alarm level (YES in step 213), a pre-alarm operation such as a pre-alarm signal being transmitted from the fire signal transmitting unit TRX is performed. (Step 216), and if it is determined that the fire is abnormal (Step 2)
12), a so-called fire operation is performed in which a fire signal is sent from the fire signal sending unit TRX (step 217). Further, if the slope K becomes smaller than the predetermined value L before it is determined that the fire is abnormal in Step 212 (Step 212).
(NO in 207), all variables in the fire determination routine are cleared (step 208), and the routine returns to the normal monitoring state.

The variables used in the fire determination routine vary depending on the fire determination routine employed, but generally include a sensor output level read at each sampling and various calculations as a function of time in the past, for example, one sample before. The result, that is, the accumulated data, etc. can be mentioned. If necessary, the elapsed time from the trigger point to the present time and the minimum value SLVmin of the sensor output level at the trigger point
In the fire determination routine based on these variables, calculations are performed for each sampling. As described above, since the calculation result in the fire determination routine is affected not only by the current sensor output level but also by the past calculation result, that is, the accumulated data, the calculation result differs depending on the setting time of the trigger point. It is important to set the trigger point as accurate as possible. In this regard, according to the present invention, an accurate trigger point is set retroactively by looking at the overall trend of the sensor output level as described above, and the calculation is started from the set past trigger point. Therefore, it is possible to obtain a high-precision fire alarm device.

As a fire determination routine that can be employed in the present invention, there is, for example, a routine described in the specification of a patent application entitled "Fire Alarm Device" filed on March 1, 1988 by the present applicant. In order to avoid false alarms, this patent application specification describes that when a trigger is applied, that is, when a gradient becomes a certain value or more, a rising function is generated, and then the sensor output level is set to a value larger by ΔV than the rising function. In this case, it is determined that a fire is determined if the number exceeds the limit. Further, as another example, a sensor output level is integrated from the time when the inclination exceeds a certain value, and when the calculated value reaches a predetermined reference integrated value, it is determined that a fire has occurred. It can be a routine for performing an arithmetic operation for integration, and similarly can be a routine for performing an arithmetic operation for differentiation or difference, and is also known as a so-called fire determination routine, such as a pattern determination or accumulation operation type. Something can be worked here.

Here, as the fire determination routine of step 211, the one described in the above-mentioned patent application specification will be described in more detail with reference to FIG. 2C. When the slope K first exceeds the fixed value L in step 207, X is set to (B) in step 210, and the sensor output level SLVmin at the point B in FIG. set the level V _T (step 221), generates a rising function V _T + aT = V ₃ based on the value of the trigger point level V _T (step 22
3). Here, T is the number of times of sampling of the sensor output level after the trigger point B, and a is a constant determined by environmental conditions.

The first loop of steps 211 to 215, compared with the corresponding values of the rise function V ₃ the values of the sensor output level in RAM1 from the trigger point B to C the current point, that the difference therebetween becomes △ V If there is even one (YES in step 212), it is determined that a fire has occurred. When the point C is reached, then steps 202 to 214
The loop, each time the sensor output level is sampled in step 212, similar comparison operation between the corresponding values of the rise function V ₃ is gradually performed.

As described above, by performing the data processing retroactively to the point B before the current point C, it is possible to grasp the situation from the start of the initial stage of the fire, thereby enabling early detection of the fire. Also, those described in the above patent application specification, after the trigger,
Constant width from rising function that rises as a function of time △
Because V is monitored, the likelihood of false alarms in environmental conditions, such as a sudden rise in temperature, is significantly reduced.

After the fire determination routine in step 211, if
When it is determined that a fire has occurred (YES in step 212), the so-called alarm operation or fire operation is performed in which the fire signal transmission unit TRX is operated via the interface IF2 to transmit a fire signal to the receiver RE (step 217). ; FIG. 2B). At this time, the fire signal transmitting unit TRX may transmit its own address together with the fire signal.

When forecasting and warning signal or fire signal from the fire detector is received by the receiver RE, the receiver RE is judged whether it has received a該予alarm signal or fire signal from any of the line L ₁ Ln, fire Indicate a potential or a fire alert area where a fire has occurred. If the fire detector also sends out its own address, the location of the fire or the activated fire detector is also determined from the received address signal and displayed together.

2A and 2B, when the slope K falls below a certain value L in step 207, the trigger that has been applied at that time is released. As a method for canceling, once a trigger has been activated in step 207, the trigger is not canceled even if K falls below L, and the determination as to whether to cancel the trigger is based on the result of the fire determination routine 211. It is also possible to do it. For example, step 206
A step is provided between steps 207 and 207 to determine whether or not a trigger has been applied. If a trigger has been applied once, step 207 is skipped and step 209 is performed directly. After the fire determination routine 211 (for example, immediately before step 214), a step is provided for determining whether or not the calculation result in the fire determination routine should release the trigger.

Further, in the above-described embodiment, the case where the present invention is applied to the fire alarm device in which the fire detector performs the fire discrimination and transmits the fire signal and / or the address signal to the receiver has been described. Is an analog fire alarm that sends out a physical quantity signal of the detected fire phenomenon, and a so-called analog fire alarm that performs a fire discrimination based on the physical quantity signal sent from the analog fire detector by a receiver or a relay. The present invention can be applied to an apparatus.

In the case where the present invention is applied to a fire alarm device in which a fire is determined by a receiver or a repeater as described above, the fire detector DE is an analog fire detector (fire sensor) in FIG. ROM1, ROM2, and RAM1 are moved to the receiver RE. The receiver RE is provided with a microprocessor, and the RAM 1 in the receiver RE is provided with sensor output level storage areas shown in FIG. 4 for the number of connected sensors. Then, in the ROM1 in the receiver RE, the connected sensor is polled and the fire detecting means of each sensor DE is detected.
An analog quantity signal is collected from the FS, and a program for executing the flowchart of FIG. 2 is added each time the signal is collected.

On the other hand, the sensor DE determines whether or not a call has been received from the receiver RE by polling, and sends a detected analog amount signal of the fire phenomenon detection means FS to the receiver RE through the transceiver TRX when the call is received. And a working RAM are provided.

[Effects of the Invention] As described above, according to the present invention, the sensor output level for a certain period of time from the past to the present time is stored in the storage unit, and the sensor output at a certain time within the certain period stored in the storage unit When the change tendency of the difference or slope between the level and the sensor output level at the present time exceeds a predetermined limit, the fire determination routine is triggered retroactively to the certain point, so that the fire phenomenon detection is performed. Even when the resolution of the sensor output level output by the means is low, there is an effect that the fire in the initial state can be detected early.

[Brief description of the drawings]

FIG. 1 is a block circuit diagram showing a fire alarm device according to one embodiment of the present invention, FIGS. 2A to 2C are flowcharts for explaining the operation of FIG. 1, and FIG. 3 is a sensor output level. FIG. 4 shows the storage area RAM1, and FIG. 4 is a graph conceptually showing an example of storage contents in the sensor output level storage area RAM1. In the figure, RE is a receiver, DE is a sensor, MPU is a microprocessor, ROM1 and ROM2 are a program storage area, RAM1 is a sensor output level storage area,
RAM2 is a work area, and FS is a fire phenomenon detecting means.

Claims (1)

(57) [Claims] 1. A storage means for storing a plurality of sensor output levels up to the present time of a physical quantity of a fire phenomenon sampled by a fire phenomenon detection means, and a sensor at a certain time stored in the storage means. Change determining means for determining whether the change tendency between the output level and the current sensor output level exceeds a predetermined limit; and the change determination means determines a change tendency of the sensor output level exceeding the predetermined limit. At this time, the data processing of the fire determination based on the sensor output level is started retroactively up to the certain point in time of the plurality of sensor output levels stored in the storage means, and after this time, the fire phenomenon detection means newly starts the processing. And a fire discriminating means for performing based on the sensor output level sampled in (1).