JP2815220B2 - Differential fire alarm - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a physical quantity representing an environmental state based on a fire phenomenon, that is, a sensor, using a fire detector or a fire sensor.
The present invention relates to a differential fire alarm device of a type that detects a level and determines a fire from a change state of the physical quantity.

2. Description of the Related Art Conventionally, when a fire detector detects a physical quantity representing an environmental state based on a fire phenomenon and performs a fire discrimination from a change in the physical quantity, for example, a differential type detecting a fire based on a rate of heat rise There are a system using a heat sensor, a system including an analog sensor that sends out ambient temperature and smoke density as an analog signal, and an analog receiver that detects a fire based on a difference value of the analog signal. In these fire alarms, the data from the past is stored and updated in chronological order, the difference between the stored past environmental data and the present environmental data is detected, and the fire discrimination is performed based on the difference. There is a method that performs the following.

[Problems to be Solved by the Invention] Here, when a fire alarm device detects a fire, it temporarily enters a standby state, and then needs to perform a recovery operation to return to the fire monitoring state. If the data in the fire alarm device of the type that stores and updates the above data in chronological order at the time when the reset is performed due to recovery or the like is rewritten to, for example, all current values, the inconvenience described below occurs. It is possible that this can happen.

For example, when a fire is detected, a fire operation such as immediately issuing an alarm is not performed. When a fire is detected for the first time, a so-called storage function may be performed, which determines that a fire has occurred. If rewritten, it is considered that the second fire detection is greatly delayed, and there is a case where a false report is made.

In addition, even in the case where a fire abnormality has not occurred, an erroneous restoration signal is generated due to, for example, noise or an erroneous operation, and the restoration signal causes all stored time-series data to be rewritten to, for example, current data. It is thought that accurate time-series changes cannot be detected, resulting in a false alarm.

[Means for Solving the Problems] Accordingly, an object of the present invention is to provide a differential type fire alarm device of a type that performs fire discrimination based on data stored in chronological order from the past, and performs a predetermined number of restorations. Until the operation is performed, the data required for performing the fire determination is not lost.

Therefore, according to the present invention, an environment detecting means for converting an environmental state relating to a fire phenomenon into a physical quantity, a storage means for storing the physical quantity from the environmental detecting means in time series, and a past stored in the storage means Determination means for performing a fire determination by comparing the stored value of the and the physical quantity from the environment detection means, recovery means for recovering the fire determination operation when a fire detection operation is performed by detecting a fire, A differential fire alarm device comprising: a counting means for counting the number of restorations by the restoration means, and when the counting means has counted a predetermined number of restorations, the stored value of the storage means is rewritten to a current value. A differential fire alarm device is provided.

[Operation] The counting means counts the number of times of recovery by the recovery means, and rewrites the stored value of the storage means to, for example, the current value only when the predetermined number of recovery operations are performed. Thus, accurate fire discrimination can be performed even after an erroneous restoration signal due to the above, and a delay in fire detection due to the restoration operation can be prevented even when the restoration operation is performed while the fire continues, such as an accumulation operation. Also,
Since the stored data is rewritten by the predetermined number of restoration signals, the fire discrimination based on the past data is stopped, and the accurate fire discrimination can be performed based on the current data.

[Embodiment] A differential fire detector of the type that performs a fire discrimination by comparing and storing stored past data and present data by chronologically storing and updating data will be described below. One embodiment of the present invention will be described with an example of an on / off type fire alarm device connected to a receiving unit such as a receiver or a repeater.

FIG. 1 is a block circuit diagram showing an on / off type differential fire alarm device according to an embodiment of the present invention, in which a receiving unit such as a fire receiver RE or a repeater is provided with a power supply. Via a signal line L, a differential fire detector SE is connected in parallel with another differential or other type of fire detector.

In the fire detector SE, the MPU is a microprocessor, R
OM1 is the program storage area, RAM1 is the work area, RAM2
RAM3 is a storage area for storing data of the previous and last two times to obtain a difference value, RAM4 is a storage area for storing a difference value, RAM0 is a storage area for storing a fire flag, and TM is a data area. A timer for setting the reading timing, CM has counters I / F1 and I / F2 for measuring the number of times the fire detector has been restored, and an interface FS has a thermistor for detecting smoke, heat, etc. based on a fire phenomenon. The environment detection unit, TX, is a signal transmission / reception unit composed of a parallel / serial converter and the like.

Note that, in this embodiment, the differential fire sensor SE stops the data update operation for storing data in a time-series manner when the recovery operation after the fire detection is performed, A description will be given of a case where the stored value to be compared with the data from the environment detection unit FS is held at the time when the fire was detected. If the storage update is stopped and the data is retained in this way, the data at the time when the first fire detection is performed will not be lost even after the recovery operation is performed,
Appropriate fire judgment is possible. However, such data retention is not essential for the operation of the present invention, and data storage and updating may be continued after the recovery operation. The main point of the present invention is that the recovery operation is performed a predetermined number of times. This is to prevent the operation of clearing all data or rewriting it to the current value until it is performed.

The operation of the fire detector of FIG. 1 will be described with reference to the flowchart of FIG.

In a normal operation in which no abnormality is detected, every time there is an output of the timer TM (Y in steps 116 and 118),
The environment value detected by the environment detection unit FS, that is, the sensor level SLV is read via the interface I / F1, and stored as current data in the work area RAM1 (step
120). When the current environment value SLV is stored in the work area RAM1, the data before the last time stored in the data storage area RAM3, that is, the environment value before the previous time, is read out, and the data before the previous time is stored in the work area RAM1. The current environment value is subtracted from the current environment value, and the difference value is stored in the storage area RAM4 (step 122). Then, the difference value stored in the storage area RAM4 is compared with a threshold value F for fire determination (steps 124 and 126).

If no fire abnormality has occurred, the environment value is smaller than the threshold value F (N in step 126). Therefore, the previous data in the previous data storage area RAM2 is moved to the data storage area RAM3 as the data before and after the previous time, and the work is performed. The current data in the storage area RAM1 is used as the previous data, and the previous data storage area RAM2 is used.
(Step 132), and waits for the next timer output (steps 116 and 118). As described above, every time the timer TM outputs the data read timing, the data is compared with the current data two times before according to the output cycle of the timer TM, and the fire is monitored.

When a fire occurs, the content of the difference value storage area RAM4 becomes larger than the threshold value F (Y in step 126), so that the content of the counter CM is first incremented by one (step S126).
138) After the fire flag is set in the storage area RAM0 (step 140), a fire signal is transmitted from the signal transmitting / receiving unit TX to the fire receiver RE via the power / signal line L (step 140).
142) Then, the fire detector SE goes into a standby state,
The state is maintained until a recovery signal from the fire receiver RE is received. Here, a case in which the data update operation is not performed in order to retain the past data in the storage area RAM3 has been described, but retaining the data is not an essential matter for the present invention. In this case, a data update operation may be performed as indicated by a dotted block 141.

Here, upon receiving the fire signal from the fire detector SE, the fire receiver RE confirms that the fire signal is not a fire signal due to a false alarm based on noise, heating, or transient cigarette smoke. In addition, it is assumed that the fire receiver is of a so-called accumulation function type, which determines whether or not the fire continues for a predetermined time. Therefore, the fire receiver RE
Upon receiving a fire signal from the fire detector SE, in order to perform this storage operation, a recovery signal is sent to the fire detector SE after a predetermined time to recover the fire detector once, and the fire detector
Only when there is a fire signal from the SE again is it determined that a real fire has occurred.

When the fire detector SE that has entered the standby state after transmitting the fire signal receives the recovery signal from the fire receiver RE after a predetermined time, the fire detector SE performs an initial setting (step 10).
2) At that time, the random access memory is not cleared. Therefore, the contents of the storage area RAM0 for the fire flag, the storage area RAM2 for the previous data, and the storage area RAM3 for the data just before the previous operation are not restored. Things are saved as is.
(If the update operation is performed in step 141, the updated data is retained.) After the initial setting, first, the contents of the storage area RAM0 are checked (step 104), and the fire flag is set. Is set (step 106), but now it is described that a fire has occurred and the fire flag is set in step 140 (Y in step 106). Next, the counter CM is checked (step 108).
If the content of the counter CM has not reached the predetermined number N (N in step 110), when there is an output of the timer TM (Y in step 118), the environment value is read from the environment detection unit FS in the same manner as described above. The current environment value is stored in the work area RAM1 (step 120), the environment value stored two times before in the storage area RAM3 is subtracted from the current environment value, and the difference value is stored in the storage area RAM4 (step 120). Step 122). At this time, the environment value before the last time stored in the storage area RAM3 is the same as the environment value before the previous time before the fire sensor SE enters the standby state, and therefore, if the fire state continues, the difference The value should be greater than or equal to the threshold value F again (Y in step 126), and the content of the counter CM is further incremented by 1 (step
138) After setting the fire flag again (Step 1)
40) A fire signal is transmitted to the fire receiver RE via the signal transmission / reception unit TX (step 142), and the apparatus enters a standby state.

For example, if it is assumed that the fire receiver RE determines that a true fire has occurred by receiving the second fire signal, appropriate measures such as fire fighting activities are taken after the fire operation is performed and an alarm is generated. Can be If the fire subsides due to fire fighting or other activities, the fire receiver RE will then restart the fire detector
Sends a recovery signal to SE and causes the fire detector to perform recovery operation. After the recovery, a new environment value is read from the environment detection unit FS into the work area RAM1 at the timing of the timer output (step 120), and a difference value from the environment value two times before is calculated (step 122). If it has calmed down, the difference value is smaller than the threshold value F (N in step 126), so that the fire flag is reset and the counter CM is cleared (step 134), and a new value in the work area RAM1 is set. The environment values are stored in the storage areas RAM2 and RAM3 as the data of the previous time and the data before the previous time, respectively, for calculating the difference value from the next time.
(Step 136), and thus the storage area R
The contents in AM2 and RAM3 are rewritten to the current values. It is not always necessary to clear the counter CM here. Thereafter, an environmental value is read for each timing output from the timer TM, and fire monitoring is performed.

In this manner, the contents of the storage areas RAM2 and RAM3 are not cleared or rewritten to the current value until the fire abnormality subsides and the environmental value returns to the normal value.
Thereafter, if it is determined that the fire has not occurred (N in step 126), the fire flag (step 140) that has been once determined to be a fire is reset (step 134), and the values of the environmental values in the previous and two previous times are set as follows: Rewritten with the current value.

In such a situation, according to the present invention, when the restoration operation is performed a predetermined number of times, the contents of the storage areas RAM2 and RAM3 are cleared or rewritten to the current value.

Thus, if it is desired that the contents of the storage areas RAM2 and RAM3 be completely updated and rewritten with the current value, the operator may perform the recovery operation a predetermined number of times.

Considering the case where the operation of retaining data after a fire occurs as in the present embodiment (the case where step 141 is not provided), the following inconvenience may occur. When using a heating device in winter, the temperature continues to rise for a certain period of time at the beginning of heating, and then becomes constant. When the difference value becomes equal to or larger than the threshold value F in the process of increasing the temperature (Y in step 126), the contents of the storage areas RAM2 and RAM3 are no longer rewritten until the heating is stopped and the ambient temperature returns to the original low temperature. Therefore fire receiver
Each time the RE sends a recovery signal, the fire detector sends a fire signal and goes into a standby state. However, according to the present invention, such a problem is solved by providing the counter CM.

That is, the counter CM counts the number of times fire detection is performed, that is, the number of times a recovery signal is received (step 138).
When it reaches a predetermined number N or more (step 11
(Y of 0), the counter CM is reset (step 112), the environment value is detected from the environment detection unit FS, and the contents of the storage areas RAM1, RAM2, and RAM3 are rewritten with the environment value just detected (step 114). As a result, the fire detector SE can monitor the fire with the newly updated data.

In the above embodiment, the cycle of the timer TM, the number of data to be stored (two in the previous embodiment and the last two in the embodiment), and the like can be arbitrarily selected.

Further, in the above embodiment, the present invention is applied to an on / off type fire alarm device in which a fire signal is transmitted to a storage function type fire receiver when a differential fire detector detects a fire. However, the present invention is also applicable to an analog fire alarm device in which a fire detector sends an analog signal to a fire receiver and the fire is determined on the fire receiver side. When applied to analog fire alarms, do not clear past data or rewrite all data to the current values even when a recovery signal etc. occurs in the receiver such as a fire receiver or repeater. In addition, when the number of occurrences of the recovery signal is counted and reaches a predetermined number, all the data may be rewritten.

Further, the present invention is also applicable to a configuration in which a difference value is calculated by a fire detector and sent to a fire receiver, and the fire is determined by the fire receiver based on the difference value.

The point is that the past data is stored in chronological order, and the fire discrimination is also performed using the past data. The operation to clear data or replace all data with the current value is not performed.

[Effects of the Invention] As described above, according to the present invention, in a differential fire alarm device that stores environmental values in chronological order, chronological past data for performing fire discrimination is determined after Or, even after the recovery operation, the operation of clearing the past data or rewriting all the data to the current value is not performed until the predetermined number of recovery operations is performed, so even after an erroneous recovery signal due to noise or erroneous operation, etc. Accurate fire discrimination can be performed, and also in a case where a recovery operation is performed while a fire continues, such as an accumulation operation, a delay in fire detection due to the recovery operation can be prevented. Also, since the stored data is rewritten by the predetermined number of restoration signals, the fire determination based on unreliable past data is stopped,
Accurate fire discrimination can also be performed based on the current data.

[Brief description of the drawings]

FIG. 1 is a block circuit diagram showing a differential fire alarm according to one embodiment of the present invention, and FIG. 2 is a flowchart for explaining the operation of FIG. In the figure, RE is a fire receiver, SE is a fire detector, FS is an environment detection unit, MPU is a microprocessor, ROM1 is a storage area with a built-in program,
RAM1 is a work area, RAM2 is a storage area for storing previous data, RAM3 is a storage area for storing data two times before, RAM4 is a storage area for storing difference values, RAM0 is a storage area for a fire flag,
TM is a timer, and CM is a counter.

Claims (1)

(57) [Claims] 1. An environment detecting means for converting an environmental state relating to a fire phenomenon into a physical quantity, a storing means for storing a physical quantity from the environmental detecting means in a time series, and a past stored value stored in the storing means. And a recovery unit for recovering the fire determination operation when a fire is detected and a fire determination operation is performed by detecting a fire by comparing a physical quantity from the environment detection unit with a physical quantity from the environment detection unit. In the differential fire alarm device, a counting means for counting the number of restorations by the restoration means is provided, and when the counting means has counted a predetermined number of restorations, the value stored in the storage means is rewritten to a current value. And differential fire alarm.