JPH041394B2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention is based on analog detection data such as temperature, gas concentration such as CO, smoke concentration, etc. The present invention relates to a fire alarm system that determines a fire by predicting and calculating the time (defined as the degree of danger).

Conventional fire alarm systems generally notify a fire by receiving on/off signals from the fire detector using a receiver, and rely on the fire detector to determine if there is a fire, so they cannot detect causes other than the fire. There is a problem in that false alarms are likely to occur due to fire alarms, and if the detection sensitivity of the fire detector is lowered to prevent false alarms, there will be a time delay in fire detection.

For this reason, in recent years, progress has been made in the development of so-called analog fire alarm devices in which analog detection data from a fire detector is sent to a receiver, and the receiver makes a fire judgment. A fire alarm system has been proposed in Japanese Patent Application No. 58-29976.

This device calculates the time until the environmental condition reaches a dangerous state for humans in the near future, that is, the limit state in which humans can survive, due to the progress of physical changes in the surrounding environment due to the occurrence of a fire. Prediction calculations are performed using the so-called difference method, which calculates the danger level based on the difference between the detection data sampled this time and the previous detection data, or the so-called function approximation method, which approximates the physical changes caused by the fire using a predetermined polynomial. However, if the calculated time is less than a certain amount of time, it is determined that there is a fire.

However, when determining a fire using such predictive calculations, detection data is sampled at a predetermined period regardless of the detected data, that is, even if the detected data value is such that it can clearly be determined that there is no fire. Each time the detection data from multiple analog detectors was sequentially sampled, predictive calculations using the difference method and function approximation method were executed to determine the presence or absence of a fire. There was a problem in that the calculation process took a long time and the time delay for fire alarms became large.

The present invention has been made in view of the above problems, and an object of the present invention is to provide a fire alarm device that can reduce arithmetic processing time as much as possible and prevent time delays in issuing fire alarms.

In order to achieve this object, the present invention provides a fire alarm system that detects changes in physical phenomena in the surrounding environment due to the occurrence of a fire in an analog manner, samples the detected data at predetermined intervals, and determines whether there is a fire.
a multi-order approximation formula calculation circuit that calculates a degree of danger, which is the time it takes to reach a predetermined danger level, based on a change trend of the detected data, using a multi-order approximation formula;
A comparison circuit is provided that instructs the multi-order approximation formula calculation circuit to start calculation only when the average value of the detected data exceeds a preset threshold.

Embodiments of the present invention will be described below based on the drawings.

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

First, to explain the configuration, 1a, 1b, ... 1n
is an analog detector that detects changes in physical phenomena in the surrounding environment due to the occurrence of a fire.
Detection unit 2 that detects temperature, gas concentration, smoke concentration, etc.
and a transmission circuit 3 for transmitting the detection data detected by the detection section 2. 4 is analog detector 1
It is a receiver in which a to 1n are connected to the signal line 5, and performs arithmetic processing based on detection data from the analog detectors 1a to 1n, and this arithmetic operation is executed by, for example, program control by a microcomputer.

In the receiver 4, 6 is a receiving circuit, which sequentially samples the detection data of the analog detectors 1a to 1n at regular intervals, and in one sampling,
For example, three consecutive detection data of one detector are extracted. 7 is an A/D that converts the analog value of the detection data detected by the receiving circuit 6 into a digital value.
A conversion circuit, 8, is the above-mentioned 3 obtained at each sampling.
This is an average value calculation circuit that calculates two digital average values.

The calculation data of this average value calculation circuit 8 is given to a storage circuit 9, and the storage circuit 9 is connected to an analog detector 1a.
It has a storage address every ~1n, and sequentially stores average value data obtained at each sampling period in each address.

On the other hand, the calculation data of the average value calculation circuit 8 is given to a comparison circuit 10, which uses the average value data and a threshold value to be set at a predetermined alarm level.
When it is determined that the average value data exceeds the threshold value Dr, a comparison output is generated that provides a calculation command for the degree of risk.

Reference numeral 11 denotes a difference value calculation circuit, which starts calculation based on the comparison output of the comparison circuit 10, and calculates current detection data (average value) An and previous detection data (average value).
Calculate the difference Sn from A _o-1 to find the slope α, α=Sn/(sampling period) (1). For example, if the detected data is temperature, the risk level R is calculated by dividing the value obtained by subtracting the current detected data (average value) An from the dangerous temperature Td corresponding to the dangerous level by this slope α. )/α (2).

Reference numeral 12 denotes a danger level reaching time judgment circuit using the difference method, which compares the danger level reaching time R calculated by the difference value calculating circuit 11 with the lower limit threshold R1 and the upper threshold R2, and determines that the time required to reach the dangerous level is short. Since the degree of danger is high, if it is below the lower limit threshold R1, the alarm display circuit 15 is activated, and if it is between R1 and R2, an output is generated to instruct the calculation of the degree of danger by the following function approximation method, When the voltage is equal to or higher than the threshold value R2, no output is generated.

The reason for performing calculations using the function approximation method after the difference method is that the calculation speed of the difference method is much faster than the function approximation method. We quickly predicted the risk, and then used a function approximation method to perform arithmetic processing to further improve the accuracy of risk prediction. This is because extremely quick and accurate risk prediction calculation becomes possible.

Reference numeral 13 denotes an approximation formula calculation circuit, which performs a calculation when the risk level R falls between the thresholds R1 and R2 in the danger level reaching time determination circuit 12, and calculates the risk level by a function approximation method.

As a function approximation method using the approximation formula calculation circuit 13, for example, taking temperature as analog detection data, an approximation formula such as F(x) = ax ² + bx + c (3) is determined, and the constant of formula (3) is determined. If a, b, and c are found from multiple average values stored in the memory circuit 9, and the danger level corresponding to the danger level is Td, then R, defined as the time to reach the dangerous temperature Td, is F(x )=Td, so it can be calculated as R={-b±√+4(-)}/2a(4).

14 is a danger level reaching time determination circuit, which sets a predetermined time as the danger threshold Rs until the temperature rise due to the occurrence of a fire reaches the limit state (danger level) in which humans can survive in the near future;
The risk level R calculated by the approximation calculation circuit 13 is the threshold value.
When the amount falls below Rs, it is determined that there is a fire and the alarm display circuit 15 is activated.

Next, the operation will be explained with reference to the flowchart shown in FIG.

First, the receiving circuit 6 includes analog detectors 1a to 1n.
We are sequentially sampling detection data from
For example, taking the detection data of the analog detector 1a as an example, sampling data D1, D2, ...Dn are detected as shown in block a of FIG.
After digital conversion in the D conversion circuit 7, as shown in block b, the average value calculation circuit 8 calculates average values A1, A2, . . . for three detected data, for example.
An is calculated and sequentially stored in the memory circuit 9.

The average value An calculated by the average value calculation circuit 8 is compared with the threshold value Dr that gives the alarm level in the comparator circuit 10, as shown in block c, and if the average value An is smaller than the threshold value Dr, processing of blocks a and b is performed. repeat.

On the other hand, when the detected data exceeds the threshold Dr at time t2 as shown in the graph of FIG. Instructs the unit to start arithmetic processing.

In this calculation process, as shown in blocks d, e, and f, the difference value Sn is obtained as the difference between the current average value An and the previous average value A _o-1 in the difference value calculation circuit 11, and the Obtain the slope α from equation (2) and finally calculate the risk R using the difference method.

Subsequently, as a process of the danger level reaching time determination circuit 12, the determination block g compares the time with the lower limit threshold value R1, and if the degree of danger R is less than the lower limit threshold value R1, the process proceeds to block k and the alarm display circuit 15 issues a fire alarm. Display together with the area of occurrence corresponding to the analog detector.

Further, if it exceeds R1, it is compared with the upper limit threshold R2 in a judgment block h. In the discrimination block h,
If the risk level R exceeds R2, the process returns to block a; on the other hand, if the risk level R is below R2, that is, the risk level R is R1.
and R2, the process proceeds to block i and calculates the degree of risk using the function approximation method based on equation (4).

Next, as shown in judgment block j, the risk level R calculated by the danger level reaching time judgment circuit 14 is determined.
It is determined whether or not the risk level is below a predetermined risk threshold Rs, and if it is below the threshold Rs, it is determined that there is a fire and an alarm is displayed in block k. Of course, if the calculated risk level R is greater than the risk level threshold Rs in the determination block j, the process returns to the block a again to sample the next detection data.

In this way, in the embodiment shown in FIG. 1, the calculation process of the degree of danger is not executed by the difference method and the function neighborhood method until the detected data (average value) reaches the alarm level Dr, and the detected data (average value) reaches the alarm level Dr. When the level exceeds Dr, the calculation of the degree of danger using the difference value and function approximation method is executed for the first time, so if data from multiple analog detectors is sequentially sampled, the detection data exceeding the alarm level due to fire will not be detected. Since a fire judgment is made by calculating the degree of danger using the difference method and function approximation method only for the detection data obtained from the analog detector, compared to the case where calculation processing is performed on all the detection data,
The time delay required to calculate a fire can be shortened, and early detection of a fire can be realized through predictive calculation.

FIG. 4 is a flowchart showing another embodiment of the present invention, and this embodiment further sets a predetermined level Ds below the alarm level Dr at which predictive calculation is started, as shown in FIG. For example, when the detected data reaches a predetermined level Ds at time t1, the degree of danger is calculated by the difference method and the function approximation method, and when the degree of danger falls below the threshold, the detected data at that time becomes the danger level Dr. If it is below, a pre-alarm will be issued and the alarm level will be increased as shown at the next time t2.
The feature is that if the Dr is changed, a fire alarm (main alarm) is issued.

That is, following the sampling of data and calculation of the average value in blocks a and b, the average value An of the detected data is compared with a predetermined level Ds in the discrimination block c, and when the average value An of the detected data is equal to or higher than the predetermined level Ds. Then, proceed to judgment block d to calculate the risk level R by the difference method, that is, execute the processing shown in blocks d, e, and f of the flowchart in Fig. 2, and then proceed to judgment block e and f to calculate the risk level. A comparison judgment is made between the arrival time R and the time lower limit threshold R1 and upper limit threshold R2, and if it is less than the lower limit threshold R1, proceed to judgment block i, and compare the detection data (average value) An at that time with the alarm level Dr. , if the alarm level is below Dr, a pre-alarm is issued in block j; on the other hand, if it exceeds the alarm level Dr, an alarm is displayed (main alarm) in block k.

Furthermore, when it is determined in the judgment blocks e and f that the risk level R is between R1 and R2, the risk level R is calculated by the function approximation method in the block g, and the threshold level of the risk level is determined in the judgment block i. Compared to Rs.
If it is less than Rs, the detection data (average value) An at that time is compared with the alarm level Dr in the discrimination block i, and if it is smaller than the alarm level Dr, a pre-alarm is issued in the block j, and if it is equal to or higher than the alarm level Dr, the block k is Displays the alarm (main alarm) with .

According to the embodiment shown in FIG. 4, when a predetermined level is reached before the alarm level is reached, a pre-alarm is issued based on the fire judgment based on the calculation of the degree of danger. Countermeasures can be prepared in advance for this warning when a fire is determined based on the calculation of the degree of risk using the function approximation method, and prompt countermeasures can be taken using this warning.

As explained above, according to the present invention, in a fire alarm device that detects changes in physical phenomena in the surrounding environment due to the occurrence of a fire in an analog manner, and samples the detected data at predetermined intervals to determine whether there is a fire, , a multi-order approximation formula calculation circuit that calculates the degree of danger, which is the time taken to reach a predetermined danger level, based on a change tendency of the detected data, using a multi-order approximation formula; and an average value of the detected data is set in advance. A comparator circuit is provided that instructs the multi-order approximation calculation circuit to start calculation only when the threshold value exceeds the threshold value.
Risk calculation processing is not performed until the detection data reaches a certain level, and even if a fire judgment is made by sequentially sampling the detection data from multiple analog detectors, the risk calculation processing is not performed. The sampling period of detection data can be shortened, and a time delay in determining a fire can be prevented.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing an embodiment of the present invention, FIG. 2 is a flowchart showing the operation of FIG. Graph diagram, 4th
The figure is a flowchart showing another embodiment of the present invention. 1a to 1n: analog detector, 2: detection section,
3: Transmission circuit, 4: Receiver, 6: Receiving circuit, 7:
A/D conversion circuit, 8: average value calculation circuit, 9: memory circuit, 10: comparison circuit, 11: difference value calculation circuit,
12: Dangerous level reaching time determination circuit, 13: Approximate expression calculation circuit, 14: Dangerous level reaching time determining circuit, 15: Alarm display circuit.

Claims (1)

[Scope of Claims] 1. A fire alarm device that detects changes in physical phenomena in the surrounding environment due to the occurrence of a fire in an analog manner, samples the detected data at predetermined intervals, and determines whether there is a fire, comprising: a multi-order approximation formula calculation circuit that calculates the degree of danger, which is the time it takes to reach a predetermined danger level based on a change trend, using a multi-order approximation formula; A fire alarm device comprising: a comparison circuit that instructs the multi-order approximation calculation circuit to start calculation only occasionally.