JP2565910B2 - Fire alarm - Google Patents

Description

Description: FIELD OF THE INVENTION The present invention relates to a fire alarm device, and more particularly to a fire alarm device itself, or a fire alarm caused by data sent from a fire sensor to a receiver via a transmission path. The present invention relates to a fire alarm device for judging.

[Prior Art and its Problems] As a detector or sensor for detecting a fire, a photoelectric smoke sensor, a thermal sensor using a thermistor, and an ionization or radiation sensor are known. Each of these fire detectors detects a given smoke density, a given temperature, or a given radiant light from a fire,
A fire signal is issued.

However, in such a system, even a transient smoke such as cigarette smoke may operate beyond its predetermined detection level.

Therefore, there is also known a storage-type sensor or receiver that does not operate due to such a transient fire phenomenon and that does not operate unless a predetermined output continues for a certain period of time using a timer or the like. However, there was a drawback that fire detection was delayed.

Furthermore, in the room where the ventilator is working, the effect is, for example, a gradual increase in the smoke concentration, which does not reach the smoke concentration that eventually activates the smoke detector and does not trigger a fire alarm, ie a false alarm There were cases like this.

[Problems to be Solved by the Invention] The present invention has been made to solve the above problems, and does not malfunction in a transient, fire-like phenomenon such as cigarette smoke, and has a gradual rise. It is an object of the present invention to provide a fire alarm device which can detect an actual fire even if it is an actual fire surely and early and issue an alarm.

[Means for Solving Problems] Therefore, according to the present invention, in a fire alarm device configured to judge a fire based on a sensor output level, a means for sampling the sensor output level at predetermined time intervals is provided. An integrating means for comparing the sampled sensor output level with a predetermined level and integrating a difference between the sampled sensor output level and the predetermined level only when the sampled sensor output level is a predetermined level or more; Change rate determining means for determining whether the output level is increasing or decreasing, and maximum value storing means for storing the maximum value immediately before the sensor output level sampled this time from the decreasing state to the increasing state And the value integrated by the integrating means is compared with a predetermined integrated value,
When it is determined that the value integrated by the integrating means has reached the predetermined integrated value, and the change rate determining means determines that the sensor output level is increasing, a signal indicating an abnormality is output. When it is determined that the sensor output level is decreasing, the maximum value of the sensor output level stored in the maximum value storage means and the current sampling are stored at the time when the sensor output level rises thereafter. The abnormality determination means is configured to determine whether to output a signal indicating an abnormality based on a comparison result between the value of the sensor output level and a predetermined level difference. When the sampled sensor output level is lower than a predetermined level, the value integrated by the integrating means is cleared.

[Operation] The sensor output level is sampled at predetermined time intervals Δt by the sampling means, and from the time when the sensor output level SLV becomes equal to or higher than the predetermined level LV, the sampled sensor output level SLV and
The difference from the predetermined level LV is accumulated by the accumulating means at each of the predetermined time intervals. In this way, the portion of the sensor output level above the predetermined level is integrated with respect to time.

The abnormality determining means compares the value integrated by the integrating means with a predetermined integrated value A, and when it is determined that the value SI integrated by the integrating means reaches the predetermined integrated value A, further, If the change rate of the sensor output level is substantially positive or negative is also determined. If it is determined to be positive, a signal indicating an abnormality is output, and if it is determined to be negative. Then, at the time when it becomes substantially positive, the overall trend of the waveform of the sensor output level is calculated from the maximum value of the sensor output level stored in the maximum value storage means and the current sensor output level value. That is, it is determined whether or not the waveform shows the increasing direction or the decreasing direction in general, and whether or not to output the signal indicating the abnormality is determined according to the result of the determination. In this way, the integrated value for the time of the part above the predetermined level is
When the predetermined integrated value A is reached, a signal indicating an abnormality is output only when the rate of change of the sensor output level is positive, so the sensor operation level is used for a sudden fire. Is set to a higher value, and a fire with a gentle rise will be detected at a low level,
Therefore, even if the rise of the sensor output level at the time of a fire occurs, stable fire detection is possible, and even if the integrated value reaches a predetermined integrated value, if the rate of change is negative, , Then, at the time when the rate of change becomes substantially positive, the overall trend of the waveform of the sensor output level, that is, it is determined whether the waveform shows a general increasing direction or a decreasing direction, Based on the result of the determination, whether or not to output the signal indicating the abnormality is determined, so that it is further ensured that the malfunction does not occur against the transient fire phenomenon.

[Embodiment] An embodiment of the present invention will be described below with reference to the drawings. First, the operation of the present invention will be described with reference to FIGS. 1A and 1B. The upper graph of FIG. 1A shows the output level SLV of the fire sensor with respect to time, and the lower graph shows the integrated value SI of the sensor output level with respect to time.
Are shown on the horizontal axis. LV is a predetermined level for starting the integration operation, and A is a predetermined integration value for generating an abnormal signal.
Now, assuming that the sensor output level SLV fluctuates along the curve S, the description will proceed.
First, at time t ₀ , the voltage exceeds the predetermined level LV, and from this time point, integration of the excess of the sensor output level SLV with respect to the predetermined level LV with respect to time is started. Specifically, this integration is performed by subtracting a predetermined level LV from the sensor output level SLV (SLV-LV) at each time interval Δt, that is, the following formula (1) Is calculated. Here, SLVk is the value of the sensor output level SLV at time tk (k = 1, 2, 3, ..., X) for each time interval Δt. In the present invention, when the integrated value SI reaches a predetermined integrated value A as a result of the calculation of the above equation (1), an abnormal signal is output and an alarm is issued only when the change rate of the sensor output level SLV is positive. Is enabled. If the sensor output level SLV is negative when the integrated value SI reaches the predetermined integrated value A, wait until the rate of change of the sensor output level SLV becomes positive, and if it becomes positive, output the sensor output. The overall trend of the level waveform is judged to determine whether or not to generate an abnormal signal.

In the present invention, as a method for determining the overall trend of the waveform of the sensor output level, when the change rate changes from negative to positive (the change rate changes from negative to positive at the minimum value of the sensor output level), the immediately preceding The maximum value and the minimum value at the time when the rate of change becomes positive are compared, and as a result of this comparison, if the difference between the maximum value and the minimum value is less than or equal to a predetermined level difference B, an alarm is activated. To output the abnormal signal. If the difference between the maximum value and the minimum value is larger than the predetermined level difference B, the abnormal signal is not output and the integrated value SI accumulated up to this point is changed to a certain smaller value. The operation of accumulating the value of the sensor output level for each Δt is continued with respect to a certain smaller value. Then, similarly to the above, if the integrated value again reaches the predetermined integrated value A and the rate of change of the sensor output level is positive, an abnormal signal for activating the alarm is output.
Even if the rate of change of the sensor output level becomes positive after the integrated value reaches the predetermined integrated value A in this way, the fire abnormality is determined depending on the global trend of the waveform. Therefore, it is possible to avoid false alarms due to a transient fire phenomenon as much as possible.

That is, when an abnormal signal for activating an alarm is generated immediately after the integrated value reaches a predetermined integrated value and the rate of change changes from negative to positive, for example, in practice, Even if it is a non-fire and the smoke concentration returns to a nearly normal state, even if the sensor output shows a rising tendency for a short time for some reason, a fire alarm will be immediately issued. Therefore, if the fire sensor output falls below the maximum value immediately before by a predetermined level difference, the integrated value is changed to a smaller value and the integrated operation is continued for this smaller value. , There are no such defects.

Taking the case of FIG. 1A as an example, i) When t <t ₀ , SLV <LV and normal, so no integration operation is performed. Ii) At t ≧ t ₀ , SLV ≧ LV, so integration operation is performed. Iii) At t = tk ₂ , the integrated value SI reaches a predetermined integrated value A,
At this point, the SLV is decreasing, that is, the rate of change is negative, so an abnormal signal for activating the alarm is not output. Iv) At time t = tk ₃ , the SLV changes from the decreasing state to the increasing state, so immediately. It is determined whether or not the previous maximum value, that is, the difference (SLV _M −SLV) between the sensor output level SLV _M at time tk ₁ and the current sensor output level SLV at time tk ₃ is less than or equal to the predetermined level difference B. , If the following, the abnormal signal for activating the alarm is output.

v) In the case of FIG. 1A, it is assumed that the difference (SLV _M −SLV) is larger than the predetermined level B, and therefore, no abnormal signal is output, but instead, it is integrated from time t ₀ to tk _3. Change the integrated value SI ₁ received to a smaller value SI ₂ .
Here, the value of this integrated value SI ₂ is the LV excess of the sensor output level SLVk ₃ at time tk ₃ and the rectangular area of the time interval (tk ₃ −t ₀ ), that is, (SLVk ₃ −LV) (tk _3- t ₀ ) or Shall be calculated by However, the method of calculating the integrated value SI ₂ is not limited to this, and for example, The calculation method of the integrated value SI ₂ to be changed should be appropriately adopted according to the usage situation.

Next, the value thus changed is adopted as the integrated value SI. After that, the integrating operation is continued with respect to the integrated value SI thus adopted.

vi) After that, even at time tk ₄ , it becomes the minimum point,
Since the integrated value SI does not exceed the predetermined integrated value A between the times tk ₃ and tk ₄ , the integrated value is not changed at this point.
In Figure 1A, the waveform repeats increasing and decreasing between the maximum and minimum, but the trend of the entire waveform shows a decrease.
The integrated value SI also does not exceed the predetermined integrated value A thereafter, and eventually decreases to a predetermined level LV at time t = tn, so an abnormal signal for activating the alarm is not output,
Moreover, the integrated value SI performed from the time t ₀ is cleared at the time tn.

In FIG. 1B, the sensor output level SLV has various straight lines S ₁ , S
₂ , S ₃ ... Ascending, and points on the graph at the time when the integrated value reaches the predetermined integrated value A are points P ₁ , P ₂ , P ₃ ... -, And the locus of those points is shown by the line L.

As shown in FIG. 1B, when the sensor output level SLV increases linearly, the operating points P ₁ , P ₂ , P ₃ ... Since the abnormal signal is output when the area of each triangle having the apex and the base of the predetermined level LV reaches the same predetermined integrated value A, that is, when the total amount of smoke reaches a constant value, For example, in the case of a fire phenomenon with a relatively sharp rise such as straight lines S ₁ and S ₂ , an abnormal signal will be output at a high sensor output level such as points P ₁ and P ₂ , and the abnormal signal due to non-fire will be output. It is possible to prevent the malfunction of output and to output an abnormal signal at a low level such as points P ₆ and P ₇ for a relatively mild fire phenomenon such as straight lines S ₆ and S _7. This will enable early fire detection. Further, as described above, when the sensor output level SLV does not rise along a straight line but the SLV changes as described in FIG. 1A, the integrated value SI reaches the predetermined integrated value A. At that time, an abnormal signal for activating an alarm is output only when the sensor output level SLV is rising, that is, when the change rate is positive, and when it is negative, no abnormal signal is generated at that time and the waveform Even if there are some maximum and minimum points in, it is determined whether or not an abnormal signal is output by checking whether the subsequent waveforms are going up or down as a whole. In the event of a fire, the occurrence of abnormal signals due to a transient fire phenomenon will be suppressed, further reducing the possibility of false alarms.

Since the line L shown in FIG. 1B is the operating point of the sensor, the predetermined level LV is set to a value sufficiently lower than the level in the conventional sensor, that is, high sensitivity.
Taking the case of a smoke sensor as an example, assuming that the smoke concentration is conventionally set to operate at 10% / m, the predetermined level LV is set to 2.5 to 3% / m, for example.

FIG. 2 shows a block circuit diagram of a fire alarm device suitable for carrying out the present invention, which has been operatively described in FIG. 1A. In the figure, the fire alarm device is the outline, the sensor unit 10,
And a determination unit 11. Here, the sensor unit 10 is a photoelectric smoke sensor that operates by sensing smoke. In the smoke detecting chamber of the smoke sensor 10, a light emitting diode LED that is pulse-lighted at a predetermined cycle by an oscillation circuit 12 and a light emitting circuit 14, and a sun that receives scattered light in proportion to its concentration when smoke flows into the smoke detecting chamber. A battery SB is provided, and after the output from the solar battery SB is amplified by the amplifier 18 via the light receiving circuit 16,
The signal is converted into a digital signal by an analog / digital (A / D) conversion circuit 20 and sent to the determination unit 11.

The determination unit 11 that receives a signal from the sensor unit 10 and performs signal processing or determination includes a microprocessor unit MP
U and interface I for receiving signals from sensor unit 10
/ F, an oscillator OSC that oscillates a clock, a read-only memory ROM1 for a program that stores a program for signal processing, and a random access memory for work
RAM1, a read-only memory ROM2 for level storage that stores a predetermined level LV for starting the integration operation, a read-only memory ROM3 for level difference storage that stores a predetermined level difference B, and A constant-storing read-only memory ROM4 storing a constant K, a predetermined accumulated-value storing read-only memory ROM5 storing a predetermined accumulated value A for generating an abnormal signal, and a predetermined time Random access memory RAM2 for storing the sensor output to capture and store the sensor output SLV at each interval Δt, and an integrated value calculated at each predetermined time interval Δt based on the sensor output level SLV captured in RAM2 Random access memory RAM3 for storing the accumulated value for storing SI, random access memory RAM4 for storing the previous sensor output level for storing the previous sensor output level, and A random access memory RAM5 of sensor maximum output value storage for storing a maximum value SLV _M Sa output level, the sensor output level
A random access memory RAM6 for storing the number of samplings for storing the number of samplings Q performed at each predetermined time interval Δt after the SLV becomes equal to or higher than a predetermined level LV for starting the integration operation is included. .

The value of the predetermined level LV for starting the integration operation, the predetermined integrated value A for generating an abnormal signal, and the predetermined level difference B are the degree of danger in the room, ventilation, air conditioning, density of people, time zone, height, It will be understood by those skilled in the art that the volume can be appropriately set and changed.

The operation of the block circuit diagram shown in FIG. 2 will be described with reference to the flowchart of FIG.

First, the determination unit 11 including the microprocessor unit MPU constantly samples the sensor output level SLV based on the program stored in the ROM 1. That is, the sensor output level SLV sent from the sensor unit 10 via the interface I / F is read into the RAM 2 at every predetermined time interval Δt counted based on the clock pulse from the oscillation unit OSC. (Step 101).
In addition, the sensor output level SLV read into RAM2 is stored in ROM2.
It is constantly compared with the predetermined level LV for starting the accumulation operation stored in the above, and it is constantly determined whether or not the predetermined level LV is reached or higher (step 102). Sensor output level SLV is LV
If it is smaller (N in step 102, that is, “no”), the accumulated value SI up to the previous time stored in the RAM3 and the sampling number Q for each predetermined time interval Δt stored in the RAM6 are cleared, The maximum value SLV _M of the previous sensor output level SLVp stored in RAM4 and the previous sensor output level stored in RAM5 is updated with the current sensor output level SLV (step 103). . If the sensor output level SLV stored in the RAM2 is larger than the predetermined level LV (Y in step 102, that is, “yes”), then a predetermined time interval Δt has elapsed since the sensor output level SLV was equal to or higher than the predetermined level LV. Each time, the sampling number Q, which has been incremented by 1 each time, is incremented by 1 again (step 103), and the accumulated value SI up to the previous time stored in the RAM 3 (SLV
−LV) is added and stored as a new integrated value SI in RAM3 (step 104). Next, it is judged whether or not the sensor output level SLV of this time is higher than the sensor output level SLVp of the previous time, and if it is higher (Y in step 105), the maximum value SLV _M stored in the RAM 5 is set as the sensor output of this time. Level SL
After updating with V (step 106), if it is not large again (N in step 105), the process goes to the next step 107 without updating. In the next step 107, it is determined whether or not the integrated value SI newly stored in the RAM 3 in step 104 is equal to or larger than a predetermined integrated value A stored in the ROM 5 (step 107), and SI is If it is not A or more, the sensor output level SLV sampled this time is stored in the RAM 4 as the previous sensor output level SLVp (step 108), then a new SLV is read (step 101), and further integration operation is performed in step 104. Continue, in this way, step 102
Until it is determined that the sensor output level SLV is smaller than the predetermined level LV in step 107, it is determined in step 107 whether the integrated value SI reaches A or not.

If it is determined that the latest integrated value SI stored in RAM3 is equal to or greater than the predetermined integrated value A stored in ROM5, then
From the previous sensor output level SLVp stored in RAM4
Subtracting the constant K stored in ROM4 and RAM2
The sensor output level SLV stored this time is compared with the current sensor output level SLV (step 109). Here, the role of the constant K is to prevent the comparison operation in step 109 from being affected even when the sensor output level SLV has an unstable minute fluctuation. As a result, in the comparison operation of step 109, it is possible to detect the sensor output level SLV that is substantially equal to or higher than the previous sensor output level SLVp, that is, whether the level is decreasing or rising. Also,
In this step 109, the sensor output level substantially above the previous sensor output level is substantially detected by the constant K in this way. This means that when the sensor output level reaches the minimum value and changes from the decreasing state to the rising state, S in step 105
Before it is determined that LV> SLVp and the maximum value SLV _M stored in RAM5 is updated in step 106, the difference between the maximum value SLV _M and the sensor output level SLV in step 110 is determined. Will be able to.

If SLV is larger than (SLVp-K), that is, if it is determined that the value is rising (Y in step 109), then the maximum value SLV
_It is determined whether or not the difference between _M and the sensor output level SLV this time is larger than a predetermined level difference B, and if it is determined not to be large (N in step 110), a fire abnormality for activating the alarm. The signal will be output (step 11).
1). If it is determined that the difference is larger than the predetermined level difference B (Y in step 110), as described above, Q × (S
LV-LV) = SI 'value is calculated and RA is calculated with this value SI'.
The integrated value SI value stored in M3 is updated and RA
The maximum value SLV _M stored in M5 is updated with the current sensor output level SLV (step 113), and the updated integrated value
It is again determined whether SI is larger than the predetermined integrated value A (step 114). If it is larger than the predetermined integrated value A (Y in step 114), the fire abnormality signal is output (step 111). If it is not larger (N in step 114), the current sensor output level SLV is the same as the previous value. After the sensor output level SLVp is stored in the RAM 4 (step 108), the next sensor output level is sampled after Δt time.

In the above embodiments, the sensor output level is described as a signal obtained from the photoelectric smoke sensor, but the sensor output level can be obtained from a thermal type, ionization type or radiation type fire sensor using a thermistor. Even in the case of a signal, the same effect as that of the above-described embodiment is obtained.

Further, in the above-described embodiment, the change rate is calculated only by the previous sensor output level SLVp to determine the positive / negative. However, the slope is calculated from the sensor output level two times before or before, and the positive / negative is calculated. May be determined.

Further, in the above embodiment, the description has been made assuming that the sensor unit and the fire determination unit of the fire alarm device are integrated.
The fire sensor output digitized by the D conversion circuit may be transmitted to a remote receiver via a model or the like so that the fire judgment can be performed here.

[Effect of the Invention] As described above, according to the present invention, a portion of the sensor output level equal to or higher than a predetermined level is integrated, and when the integrated value reaches the predetermined integrated value, the rate of change of the sensor output level is positive. Since the abnormal signal is output only in the case of, it is possible to detect the fire at a high level when the fire is suddenly rising and at a low level when the fire is slowly rising. At the same time, if the rate of change is negative, then wait until it becomes positive, and if it becomes positive,
The overall trend of the waveform, that is, whether the waveform is in the ascending direction or in the decreasing direction as a whole, is determined.If it is determined that the waveform is in the ascending direction, a fire abnormality signal is output, and it is determined that the waveform is decreasing. If it is judged, the integrated value up to the previous time was changed to a smaller value and the integrated operation was continued, so it does not malfunction for a transient fire phenomenon, but the smoke concentration There is an effect that the fire alarm device can be more reliably obtained by operating for a fire that gradually increases.

[Brief description of drawings]

1A and 1B are graphs for explaining the operation of the present invention, FIG. 2 is a configuration diagram showing a fire alarm device according to an embodiment of the present invention, and FIG. 3 is an operation of FIG. 4 is a flowchart for explaining In the figure, 10 is a smoke sensor section, 11 is a discrimination section, MPU is a microprocessor unit, ROM 1 is a read-only memory for program storage,
RAM1 is a random access memory for work, SLV is the sensor output level, SLVp is the previous sensor output level, SLV _M is the maximum value of the sensor output level, LV is the predetermined level for starting the integration operation, SI is the integration value, and A is A predetermined integrated value for generating an abnormal signal, B is a predetermined level difference, Q is the number of samplings, Δt
Is a predetermined time interval.

Claims (2)

(57) [Claims] 1. A fire alarm device adapted to judge a fire on the basis of a sensor output level, means for sampling the sensor output level at predetermined time intervals, and the sampled sensor output level and the predetermined level. And comparing means for integrating the difference between the sampled sensor output level and the predetermined level only when the sampled sensor output level is equal to or higher than the predetermined level, and the sensor output level is increasing. Change rate determining means for determining whether it is decreasing or not, maximum value storage means for storing the maximum value immediately before the sensor output level sampled this time from a decreasing state to an increasing state, and an integrating means for integrating The calculated value is compared with a predetermined integrated value, and the value integrated by the integrating means reaches the predetermined integrated value. When it is determined that the sensor output level is increasing by the change rate determining means, a signal indicating an abnormality is output, and it is determined that the sensor output level is decreasing. When the sensor output level rises, the difference between the maximum value of the sensor output level stored in the maximum value storage means and the value of the sensor output level sampled this time is then set to a predetermined value. And an abnormality determining means for determining whether to output a signal indicating an abnormality based on a result of comparison with the level difference of the abnormality detection means. The fire alarm device is characterized in that when it is smaller, the value accumulated by the accumulating means is cleared. 2. The abnormality determining means, when the difference between the maximum value of the sensor output level stored in the maximum value storing means and the value of the sensor output level sampled this time is smaller than a predetermined level difference. The fire alarm device according to claim 1, wherein the fire alarm device outputs a signal indicating an abnormality, and rewrites the value integrated by the integrating means to a smaller value when the level difference is larger than a predetermined level difference.