JPH0224798A - Differential fire alarm device - Google Patents

Abstract

PURPOSE:To suppress the generation of malfunction by finding out a 1st prescribed time of a small time constant or the average value of the number of times in a detecting level of heat, smoke or gas for a prescribed time, finding out an average value for a 2nd prescribed time of a long time constant or the number of times, and when a difference between both the values reaches a differential width, deciding a fire. CONSTITUTION:A solid line CUR shows the value of a current practical sensor level SLV, a dotted line tauA shows the average value of the sensor level SLV for a long period and a dotted line tauB shows the plot of the average of the sensor level SLV for a short period. In case of a temporary fire, a difference between both the dotted lines tauA, tauB is small, but when the difference is large, a fire alarm is outputted when the difference exceeds the differential width C. Namely, the mean value over a long period has an effect suppressing the influence of a moderate environment change and a mean value for a short period has a strong merit for noise because an averaged level is generated against a suddenly changed sensor level and the mean value slightly follows in instantaneous phenomenon.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention provides a differential fire alarm system that determines a fire when the degree of change in fire phenomena such as heat, smoke, or gas exceeds a predetermined level. It is related to.

[Prior Art] For example, Japanese Utility Model Publication No. 59-28333 and Japanese Utility Model Publication No. 58-44465 disclose methods for monitoring the degree of change in temperature, that is, the rate of temperature change, and that the rate of temperature change reaches a certain rate of increase. This shows a so-called differential fire detector configured with an electric circuit, which outputs a fire signal to a receiver when the rate of increase continues to exceed a certain value for a certain period of time.

In such conventional differential fire detectors, the constant rate of temperature rise for fire detection, or the certain period of time during which the constant rate of temperature rise must continue, is always constant regardless of the environmental temperature around the heat detection part. For this reason, if you turn on the heating in the winter when the room temperature has dropped to, say, 0℃, the sensor installed on the ceiling will suddenly raise the temperature and There is a drawback that the temperature rise rate is exceeded and the set period of time also elapses, resulting in malfunction. On the other hand, like in a boiler room, the temperature is always 40 to 50℃.
In some environments, even in the event of a fire outbreak, it is difficult to obtain a predetermined rate of rise as well as a certain lapse of time, which has the disadvantage that the detection of the fire is delayed. As described above, depending on the environmental temperature conditions, a differential heat sensor cannot be used, and a constant temperature heat sensor must be installed instead.

[Problems to be Solved by the Invention] As described above, conventional differential fire alarm devices such as differential heat detectors have the problem that depending on the environmental conditions, malfunctions, weekly alarms, or missed alarms are likely to occur. there were.

Means for Solving Problem L] The present invention has been made to solve the above problem, and the present invention has been made in order to solve the above problem. In a differential fire alarm system that determines a fire when a predetermined difference from a standard level is reached, the standard level can follow gradual changes in the environment, and it also prevents transient noise such as noise. The purpose is to prevent malfunctions due to phenomena.

Therefore, in the present invention, the average value of a time constant (first predetermined time or number of days) smaller than the fire phenomenon detection level output from the fire phenomenon detection means is determined, and the average value of a longer time constant (first predetermined time or number of days) is determined. (a second predetermined time or number of times greater than the time or number of times) is calculated, and a fire is determined to occur when the difference between the average value of the short time constant and the average value of the long time constant reaches a predetermined value. .

Specifically, according to the present invention, there is provided a fire phenomenon detection means (FS) that detects a physical quantity of a fire phenomenon such as heat, smoke, gas, or light, and a detection level of a fire phenomenon output from the fire phenomenon detection means. The first step is to calculate the average value (P) for the first predetermined period of time or for the number of days (inquiry + 1).
means (step 103, RAMI, DIPI); and a second predetermined time period or number of days (n+1 ) for determining the average value (Q>) (step 103, RAM 1, DI
P2>, and fire discrimination means (which determines that there is a fire when the difference between the average value obtained by the second means and the average value obtained by the first means becomes a predetermined value (C) or more); Step 104) A differential fire alarm device is provided.

Further, the first means and/or the second means may include a changing means (D
A differential fire alarm device having IPl, DIP2> is also provided.

[Operation] The first and second means calculate the average value of the detection levels for the first and second predetermined times or days, respectively, by weighted averaging or moving element equality. The long-term average value obtained by the second means follows environmental changes with a delay, so it is effective as a reference level after environmental changes. Further, the short-term average value obtained by the first means is selected so as to respond relatively quickly to environmental changes such as fire, but to respond with a delay to transient phenomena. in this case.

If only the long-term average value obtained by the second method is used, it will malfunction in response to transient phenomena.
Therefore, if the fire discriminating means is made to determine that there is a fire when the difference between the short average value and the long average value exceeds a predetermined value, a differential fire alarm system that does not cause false alarms or miss alarms can be realized. can get.

Further, if the first means and/or the second means have a changing means and can change the predetermined time, the predetermined number of times, the weight value, etc., the settings are always optimal for the environmental conditions. be able to.

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

Figure 1 shows changes in the detection level or sensor level SLY (vertical axis) with respect to time t (horizontal axis), and Figure 1 (a) shows the case where a transient phenomenon such as noise occurs.
In addition, Fig. 1(b) shows an example of a fire outbreak.
In the figure, the solid line CυR is the current actual sensor level SLY
The dotted line τA shows the plot of sensor level SLY averaged over a long period (simple average, moving average, weighted average, etc.), and the dotted line τ
B shows a plot of sensor level SLV averaged over a short period of time (simple average, moving average, weighted average, etc.). In the transient case of Figure 1(a), the difference between the dotted line τA and the dotted line τB is small, but in the case of a fire outbreak in Figure 1(b), the difference between the two is large and exceeds C during the differential. Appropriate fire action, such as outputting a fire alarm, is taken at that point.

The advantages of this method are that the long time constant, that is, the average value over a long period, has the effect of suppressing the effects of gradual changes in the environment; Since the value is an average level for sensor levels that change rapidly, the average value hardly follows instantaneous phenomena, and has a strong advantage against noise. In addition, since the system is designed to operate when the difference between the two average values reaches a predetermined differential value, the sensitivity is maintained constant without reducing sensitivity to gradual environmental changes, and it is able to withstand transient phenomena. has the function of suppressing malfunctions.

FIG. 2 is a block circuit diagram showing an example of a fire alarm device to which an embodiment of the present invention is applied, and in the figure, RE is a fire receiver, DE, .
+~DEnn are connected to the fire receiver R by a pair of power and signal lines Ll□Ln for each fire alarm area, respectively.
This is a fire detector connected to E. In addition, fire detector D
Although only the inside of E + + is shown in detail, the same applies to other fire detectors.

In the fire detector DE+1, MPU is a microprocessor, and ROM1 is a program storage area in the main memory associated with the microprocessor MPU, which permanently stores a program that will be described later with reference to the flowchart of FIG.

ROM2 is a storage area of a predetermined differential width in the main memory in which a predetermined differential width C is fixedly stored; The sensor level storage area in the main memory is for storage, RAM2 is the work area in the main memory, and FS is a fire phenomenon detection unit that detects physical quantities related to fire, including thermal type, smoke type (ionization), It has a detection unit such as a type (type, scattered light type, attenuation type, etc.), gas type, or radiation type, a sample hold circuit, and an analog/digital converter.

DIPI and DIR2 are dip switches that can change the settings of the first and second predetermined times, respectively; is a transmitting/receiving unit), and IFI to IF4 are interfaces.

The operation shown in FIG. 2 will be explained with reference to the flowchart shown in FIG.

First, the detection output level, that is, the sensor level SLV, which is converted into a digital signal by the analog-to-digital converter from the fire phenomenon detection unit FS, is sent to the interface IF.
I is read into the working area RAM2 every few seconds, for example every 2 seconds (step 101), and the sensor level read into said RAM2 is then read into the sensor level storage area R.
Written to AM1 as the current level. At that time, the oldest data is discarded (step 102).

The sensor level storage area RAM1 is shown in FIG. 4, and the sensor level for the first predetermined time period or number of times +1 is stored from address O to 0, and is larger than 0. Data (i.e., sensor level) for a second predetermined time period or number of times (n+1) are shown stored up to address n. The sensor level storage area RAM1 itself can be configured to
It has a storage area up to an appropriate address value LAST larger than the address n so that the settings can be changed as appropriate with the switch DIR2. The latest data, i.e., the sensor level, is stored at the top of the storage area, the data stored up to that point is sequentially shifted down one by one, and the data at the end, i.e., at address LAST, is stored. is thrown away. In this way, the LAST is always up-to-date.
+ 1 minute of data is stored.

Once the latest sensor level SLV is stored in the top location of the sensor level storage area RAM, the values of logic and n set in the dip switches DIPI and DIP2 are read. Then, the moving average sensor level P is calculated by summing up the sensor levels for the latest first predetermined time or number of times n+1 stored in the sensor level storage area RAM l, and dividing the sum by m+1. At the same time, the moving average sensor level Q is calculated by summing the sensor levels for a second predetermined time or number of times n+1 and dividing the sum by n+1 (Stella 1103), the decimal point resulting from the division. Parts below the point may be discarded.

Next, the difference between the moving average sensor levels P and Q is taken and the difference is compared with the differential medium C stored in the storage area ROM2 (step 104).

If the difference is smaller than the differential C (N in step 104), read the next sensor output level and step 101
The operations from then on will continue in the same way. Furthermore, if the difference is greater than or equal to differential C (Y in step 104), appropriate fire action is taken, such as operating the fire signal sending unit TRX via the interface IP2 to send a fire signal to the receiver RE. (Step 105). At this time, the fire signal sending unit TRX may send out its own address together with the fire signal. After the fire operation, the fire signal sending unit TRX waits for a time (
Step 106), the next sensor level reading is performed in step 101 at the next reading time.

When a fire signal from a fire detector is received by the receiver RE, the receiver RE determines from which line, ~Ln, the fire signal was received, and displays the fire warning area where the fire occurred. . In addition, if the fire detector also sends out its own address, the location of the fire or the activated fire detector is determined from the received address signal and displayed together.

In the above embodiment, the values of 0 and n set by the dip switches DIPI and DIR2 are used in step 10.
3 shows the case where the average value is read from the dip switch when calculating the average value, but it may be read in advance at the time of initial setting.

Furthermore, in the above embodiment, the average value is determined by a moving average, but the average value may also be determined by other averaging methods such as a simple average or a weighted average. The type of average value used may be changed, such as an average or a weighted average for a long average value. If the average value is a weighted average, the values of eyelid and n will each be the weighted value of the weighted average. . (Note that if both average values are weighted averages, the storage area RAM1 becomes unnecessary.) Furthermore, the values of bite and n are automatically determined by a timer rather than a switch, for example, depending on the morning and evening or the season. You can also change it to . In this case, the change time and the corresponding values of 1 and n are stored in the storage area ROM2.
In any case, the seagull and/or
Alternatively, when changing the value of n, the condition is that m < n.

Further, in the above embodiment, the present invention is applied to a fire alarm device in which a fire detector performs fire discrimination and sends a fire signal and/or an address signal to a receiver. is an analog fire detector that sends out a physical signal of the detected fire phenomenon, and a receiver or repeater uses the physical signal sent from the analog fire detector to identify a fire, which is a so-called analog fire alarm. It is also possible to apply the present invention to a device.

As described above, when the present invention is applied to a fire alarm device in which fire discrimination is performed using a receiver or a repeater, the fire detectors D E + 1 to DEnn in FIG. 1 are analog fire detectors (fire sensors). Therefore, in each fire sensor, the predetermined differential medium storage ROM2, senna level storage RAM1, and dip switches DIPI and DIP2 are omitted, and the fire signal transmitter TRX sends and receives signals to and from the receiver RE. This is the transmitting/receiving section that performs the functions. When the program storage ROM 1 receives a call from the receiver RE by polling, data on the detection output level of the fire phenomenon detection section FS is sent to the receiver RE via the transmitting/receiving section TRX.
The program to be sent to is stored.

On the other hand, the receiver RE or repeater includes a microprocessor MPU in the fire detector DE shown in FIG.
M2, sensor level storage R, AMl, working RAM
2, a transmitter/receiver unit TRX, etc. are provided. The program storage ROM 1 is stored in the program storage ROM 1 by sequentially polling a plurality of connected fire sensors and setting each sensor level S.
Each time the LV is read and the sensor level SLV is read, a fire discrimination is performed for each fire sensor according to a flowchart similar to that shown in FIG. 3, and a program is stored that causes the results to be displayed on a display unit or the like. Further, the sensor level storage RAM 1 is provided with a storage area capable of storing sensor levels for each of a plurality of connected fire sensors.

[Effects of the Invention] As described above, according to the present invention, the average value of the detection level of heat, smoke, gas, etc. for a predetermined period of time read continuously for a first predetermined time period or number of times with a small time constant. At the same time, we calculated the average value for a second predetermined time or number of times with a long time constant, and determined that there was a fire when the difference between the two reached a predetermined differential, so gradual environmental changes could be detected. It has the function of suppressing malfunctions in response to transient phenomena while maintaining constant sensitivity.

Further, since the number and n of the sensor levels for the first and second predetermined times or the number of times can be changed by the changing means, for example, the layer can be made smaller in a place with little noise, and the layer can be made smaller in a place with a lot of noise. In this case, settings can be made to suit the environment, such as increasing the size of the pocket to prevent malfunctions caused by noise. Therefore, it is possible to obtain a differential fire alarm system that is free from false alarms and misses alarms.

[Brief explanation of the drawing]

FIG. 1 is a diagram for explaining the present invention in detail, FIG. 2 is a block circuit diagram showing a fire alarm device according to an embodiment of the present invention, and FIG. 3 is a diagram for explaining the operation of FIG. 2. FIG. 4 is a diagram showing details of the sensor level storage area RAM1 in FIG. 2. In the figure, RE is the receiver, DE, . Fire phenomenon detection unit, ROMI is a program storage area, ROM2 is a predetermined differential storage area, RA
M1 is a sensor level storage area, RAM2 is a work area,
DIPI and DIR2 are dip switches (changing means), and TRX is a fire signal sending section. ↑ Figure 1 Monthly Figure 3

Claims (2)

[Claims] (1) A fire phenomenon detection means for detecting physical quantities of fire phenomena such as heat, smoke, gas, or light, and a first predetermined time period or number of times of the detection level of the fire phenomenon output from the fire phenomenon detection means. a first means for calculating an average value of the fire phenomenon detection level outputted from the fire phenomenon detection means for a second predetermined time period or number of times that is greater than the first predetermined time period or number of times; and fire discrimination means for determining a fire when the difference between the average value obtained by the second means and the average value obtained by the first means becomes abnormal by a predetermined value. A differential fire alarm device characterized by comprising: and. (2) The differential fire alarm according to claim 1, wherein the first means and/or the second means includes changing means for changing a predetermined time, a predetermined number of times, or a weight value. Device.