JP5091956B2 - Fire alarm system - Google Patents

Description

  The present invention relates to a fire alarm system that transmits a radio signal between a plurality of fire alarm devices.

  For radio equipment (radio stations) used in Japan, the characteristics of radio waves used (RF characteristics) such as occupied frequency bandwidth and adjacent channel leakage power must satisfy the regulations of the Radio Law. In the Radio Law, different standards (communication standards) are defined for each purpose of use. For example, the “specified low-power radio station” defined in Article 6 of the Radio Law Enforcement Regulations uses a telemeter for automatically displaying or recording the measurement results of remote measuring devices using radio waves. , For telecontrol that transmits signals for the purpose of starting, changing or terminating the function of a device at a remote point using radio waves, and transmission of information processed mainly by machines or transmission of processed information "Specified low power radio station telemeter, telecontrol and data transmission radio equipment standards (Radio Industry Association Standard ARIB STD-T67)" or mainly fire "Small power," which is defined for the wireless facilities of the low power security system that reports theft or other abnormalities or controls associated therewith There is a radio equipment standard for security system radio stations (Radio Industry Association Standard RCR STD-30).

  On the other hand, as a wireless transmission system provided with the specific low-power radio station, there is a fire alarm system as described in Patent Document 1, for example. In such a fire alarm system, a plurality of fire alarms (radio units) installed at multiple locations have a function of detecting a fire and a function of sounding an alarm sound, respectively. When a fire is detected, the fire alarm sounds an alarm sound and transmits information (fire detection information) to notify the fire detection to other fire alarms by radio signal. In addition, multiple fire alarms can be linked together to sound an alarm sound all at once, so that the occurrence of a fire can be notified quickly and reliably.

  Such a fire alarm is driven by a battery as a power source in order to take advantage of the characteristic of transmitting fire detection information with a radio signal, and is usually in a place where maintenance (for example, battery replacement) is difficult such as indoor ceilings. Since it is installed, it is desirable that it can be used without maintenance for a long period of time such as several years. Therefore, in each fire alarm device, the receiving circuit is intermittently activated to check whether or not a desired radio wave (radio signal transmitted by another fire alarm device) can be received. It is desired to significantly reduce the average power consumption by stopping the receiving circuit and shifting to the standby state.

JP 2006-343983 A

  However, when the intermittent reception operation is performed as described above, the timing of receiving the wireless signal that should be received originally is delayed by the intermittent reception interval of the reception circuit, and the response speed in the interlocking operation becomes slow. End up. Therefore, the intermittent reception interval cannot be simply extended for the purpose of reducing power consumption. For example, if the delay period until interlocking is to be suppressed to about 6 to 10 seconds at the maximum, at least the intermittent reception interval is set to 10 seconds or less. There is a need to. That is, in order to ensure the response speed required in practice, it is necessary to perform the reception operation to some extent frequently. In addition, the above-mentioned standard for specific low-power radio stations stipulates a period during which radio waves can be continuously transmitted from a radio (transmission period) and a period during which radio waves are not transmitted (pause period). In order to comply with the above, the fire alarm device of the fire source can also transmit a radio signal only during the transmission period, and this may cause a slow response speed.

  The present invention has been made in view of the above circumstances, and an object thereof is to provide a fire alarm system capable of reducing power consumption of a fire alarm device and shortening a delay time of information transmission. .

  In order to solve the above-described problems, the invention of claim 1 is a fire alarm system comprising a plurality of fire alarms, each fire alarm having a fire detection means for detecting the occurrence of a fire and a radio signal. Transmitting means for transmitting, receiving means for receiving radio signals, timer means for repeatedly counting a constant intermittent reception interval, notifying means for notifying that a fire has been detected by the fire detecting means, transmitting means and receiving means Control means for controlling the means, one of a plurality of fire alarms as a parent unit, the remaining fire alarm as a child unit, the control means when the fire detection means detects the occurrence of a fire A transmission operation that activates the transmission means and transmits a notification signal including a notification signal in a frame that notifies the occurrence of a fire in a predetermined transmission period; and a radio signal that activates the reception means and activates the reception means in a predetermined pause period. When the fire detection means does not detect the occurrence of fire, the reception means is stopped while the intermittent reception interval is counted by the timer means. Each time the intermittent reception interval count by the timer means is completed, intermittent reception processing is performed to activate the reception means. When the notification means transmitted by the slave unit is received by the reception means, the reception means Ending prediction processing for predicting the end of the transmission period in which the received notification signal is transmitted, and transmission of the notification signal to all the slave units from the end of the transmission period predicted by the end prediction processing to the transmission means And interlocking instruction processing to be performed.

  According to the first aspect of the present invention, when the fire detection means detects the occurrence of a fire, the transmission means is activated to transmit a notification signal consisting of a radio signal including a notification message in a frame during a predetermined transmission period, and a predetermined pause. The transmission of the radio signal is suspended during the period, and the transmission unit is stopped when the fire detection unit does not detect the occurrence of the fire, and the reception unit is stopped during the intermittent reception interval counting by the timer unit, and the intermittent reception by the timer unit Since the receiving means is activated each time the interval count is completed, the power consumption of the fire alarm can be reduced, and when the master unit receives the notification signal transmitted by the slave unit, the master unit receives the received notification signal. Since the transmission of the notification signal to all the slave units starts from the predicted end time, the transmission period of the notification signal of the slave units ends. The time it takes for the master unit to start sending the notification signal is shortened, and the transmission period of the notification signal is substantially doubled. Therefore, after the slave unit first starts sending the notification signal, By the end of the transmission of the notification signal, the possibility that the slave unit receiving intermittently receives the notification signal can be increased, and as a result, the delay time of information transmission can be shortened.

  According to a second aspect of the present invention, in the first aspect of the invention, the control unit causes the transmission unit to transmit the notification signal by transmitting the notification signal a predetermined number of times within the transmission period. The frame includes a serial number indicating what number was transmitted in the transmission period, and the control unit of the master unit predicts the end time when receiving the notification signal once by the receiving unit. In the end prediction process, the notification signal is transmitted based on the number of consecutive transmissions of the notification signal within the transmission period and the serial number included in the notification signal received by the receiving unit. The end of the transmission period is predicted.

  According to the second aspect of the present invention, when the notification signal is received even once by the receiving means, the control means of the master unit starts the end time prediction process, so the end time is set before the end time of the transmission period elapses. The possibility that it can be predicted increases, and it is possible to reduce the time required from the end of the transmission period of the notification signal of the slave unit to the start of transmission of the notification signal by the master unit.

  According to a third aspect of the present invention, in the first aspect of the invention, the control unit causes the transmission unit to transmit the notification signal by transmitting the notification signal a predetermined number of times within the transmission period. The frame includes a serial number indicating the number of transmissions in the transmission period, and the control unit of the parent device predicts the end time when the reception unit receives the notification signal a plurality of times. In the end prediction process, the notification signal is generated based on the number of continuous transmissions of the notification signal within the transmission period and the serial numbers included in the plurality of notification signals received by the reception unit. It is characterized by predicting the end of the transmitted transmission period.

  According to the invention of claim 3, since the control means of the master unit receives the notification signal a plurality of times by the receiving means and starts the end time prediction process, the time interval between the received notification signals, the serial number, the serial number, etc. Since the deviation of the timer between the parent device and the child device can be corrected from the number of transmissions and the like, the reliability at the end of the transmission period predicted by the end time prediction process can be improved.

  The present invention has the effects of reducing the power consumption of the fire alarm and reducing the delay time of information transmission.

It is a system configuration figure of the fire alarm system of one embodiment of the present invention. It is operation | movement explanatory drawing of a fire alarm system same as the above. It is a data format of the frame of the notification signal in the same as above. It is explanatory drawing of the other example of a fire alarm system same as the above.

  As shown in FIGS. 1 and 2, the fire alarm system of one embodiment of the present invention includes a plurality (four in this embodiment) of fire alarms TR. This fire alarm device TR transmits a radio signal using radio waves as a medium from the antenna 3 and receives a radio signal by the antenna 3, a control unit 1 that controls the transceiver 2, and when a fire is detected A fire detection unit 4 for notifying the control unit 1 of fire detection, a notification unit 5 for notifying that the fire detection unit 4 has notified the control unit 1 of the detection of fire (ie, the occurrence of a fire), and a dry battery A power source 6 that supplies operating power to each unit using a battery such as a battery, and a container (not shown) that houses them and is installed on the ceiling of a dwelling unit or the like.

  A unique identification code is assigned to the fire alarm device TR, and the destination of the radio signal and the source fire alarm device TR can be specified by the identification code. Here, after installing the fire alarm system, an identification code unique to the fire alarm TR is registered in association with a predetermined identification number. After this registration, the fire alarm is used instead of the identification code. The radio signal may be transmitted / received using a number that can identify the device TR, and in this way, data (telegram) transmitted by the radio signal can be shortened.

  In the fire alarm system of the present embodiment, one of the four fire alarms TR is used as a master unit and the remaining three fire alarms TR are used as slave units. Therefore, in the following description, of the four fire alarms TR, the fire alarm TR used as a parent unit is denoted by reference numeral TR1 as necessary, and the fire alarm TR used as a slave unit is denoted by reference numeral TR2 as necessary. Represented by Further, as necessary, the fire alarm device TR1 is represented as a parent device TR1, the fire alarm device TR2 is represented as a child device TR2, and further, a plurality of child devices TR2 are represented by symbols TR2A to TR2D as necessary. The master unit TR1 and the plurality of slave units TR2 include all the slave units TR2 in the radio signal transmission range (communication area) of the master unit TR1, and each radio unit TR2 has a radio signal transmission range. Are arranged such that a parent device TR1 and a child device TR2 other than itself exist.

  The fire sensing unit 4 senses a fire by detecting smoke, heat, flame, etc. generated by the fire, for example. In addition, since the detailed structure of the fire detection part 4 is conventionally well-known, detailed description is abbreviate | omitted.

  The transmission / reception unit 2 includes a transmission circuit unit (not shown) that transmits a radio signal from the antenna 3 and a reception circuit unit (not shown) that receives a radio signal from the antenna 3. Radio signals using radio waves as a medium are transmitted and received in accordance with the “specified low-power radio station” defined in the Article. Note that in the transmission / reception unit 2, the transmission circuit unit and the reception circuit unit are alternatively activated (the reception circuit unit is stopped when the transmission circuit unit is activated, and the transmission circuit unit is deactivated when the reception circuit unit is activated). ). Therefore, the transmission / reception unit 2 functions as a transmission unit that transmits a radio signal by activating the transmission circuit unit, and functions as a reception unit that receives a radio signal by activating the reception circuit unit.

  The control unit 1 is, for example, a microcomputer (microcomputer) or the like, and is a control unit that realizes various functions by executing a program stored in a memory by a CPU. In the fire alarm system of the present embodiment, the contents of the program stored in the memory of the control unit 1 are partially different between the parent device TR1 and the child device TR2 (that is, the control unit 1 is different from the parent device TR1 and the child device TR2). And a function different between the parent device TR1 and the child device TR2). Therefore, in the following description, in order to distinguish between the control unit 1 of the parent device TR1 and the control unit 1 of the child device TR2, the control unit 1 of the parent device TR1 is referred to as a parent device side control unit as necessary. The control unit 1 of the slave unit TR2 is referred to as a slave unit side control unit and is represented by the reference symbol 1B.

  When the fire detection unit 4 detects the occurrence of a fire, the control unit 1 drives a speaker (not shown) provided in the notification unit 5 to generate a notification sound (alarm sound) at a predetermined cycle (for example, every 4 seconds). Notify that a fire has occurred by ringing. In addition, when the transmission / reception unit 2 receives a notification signal described later, the control unit 1 drives a speaker included in the notification unit 5 to notify that a fire has occurred.

  In addition, when the fire detection unit 4 detects the occurrence of a fire, the control unit 1 generates a notification message for notifying that a fire has occurred in order to sound a notification sound of the occurrence of a fire in other fire alarms TR. A fire occurrence notification process is performed in which the transmission / reception unit 2 transmits the notification signal including the wireless signal included in the frame. In the fire occurrence notification process, the control unit 1 activates the transmission circuit unit of the transmission / reception unit 2 to transmit a notification signal during a predetermined transmission period Tx and the reception circuit of the transmission / reception unit 2 as shown in FIG. And a reception operation for enabling reception of a radio signal in a predetermined pause period (reception period) Rx is alternately repeated a plurality of times.

  As described above, the transmission operation and the reception operation are alternately performed, that is, the control for repeating the transmission period Tx and the idle period Rx alternately is performed in accordance with “specific radio equipment for a low power radio station, telecontrol, and data transmission. In the “Standard (Radio Industry Association Standard ARIB STD-T67)” and “Radio Equipment Standard for Low Power Security System Radio Station (Radio Industry Association Standard RCR STD-30)” This is because a period (transmission period) that can be transmitted continuously and a period during which a radio signal should not be transmitted (pause period) provided between the transmission period and the transmission period are defined. . For example, the standard ARIB STD-T67 specifies a transmission period of 40 seconds or less and a pause period of 2 seconds or more, and the standard RCR STD-30 specifies a transmission period of 3 seconds or less and a pause period of 2 seconds or more. Yes. In view of the above standards, in the fire alarm system of the present embodiment, the transmission period Tx is set to 2.8 seconds, and the pause period Rx is set to 2.5 seconds.

  By the way, when transmitting the notification signal to the transmission / reception unit 2, the control unit 1 continuously transmits the notification signal a predetermined number of times (28 times in the present embodiment) within the transmission period Tx. Here, the data format of the frame of the radio signal transmitted and received between the fire alarms TR is, for example, as shown in FIG. 3, a synchronization signal SY composed of synchronization bits (preamble) PR1 and PR2 and a frame synchronization pattern (unique word) UW. And a header H storing a transmission source address, a transmission destination (destination) address, etc., data D storing various messages such as a notification message, and an error detection code (CRC code) CRC. In the fire alarm system of the present embodiment, since the notification signal is continuously transmitted 28 times within the transmission period Tx of 2.8 seconds, 100 ms (480 bits = 60 bytes) is assigned to one notification signal.

  Here, the synchronization bit PR1 is provided to adjust the bit length of the notification signal. The header H further includes a serial number (frame serial number) indicating the number of the notification signal transmitted in the transmission period Tx. Moreover, if the identification code of each fire alarm device TR is set as the transmission destination address of the header H, only the fire alarm device TR of the identification code receives the radio signal and acquires the data. By setting a special bit sequence (for example, a bit sequence in which all bit sequences are set to 1) that is not assigned to the device TR, the radio signal is broadcast (broadcasted) and all the fire alarm devices TR can acquire data. it can.

  By the way, when the fire detection unit 4 does not detect the occurrence of a fire, the control unit 1 activates the reception circuit unit of the transmission / reception unit 2 and transmits a radio signal (a wireless signal transmitted by another fire alarm device TR) by the antenna 3. Signal). In this state, the control unit 1 performs a radio wave check for determining whether a radio signal can be received. In performing the radio wave check, a received signal strength indication signal (RSSI signal), which is a DC voltage signal proportional to the magnitude of the received signal strength, output from the transmission / reception unit 2 can be used. Such a check method using an RSSI signal is well known in the art, and will be described in detail.

  If the control unit 1 determines that the radio signal cannot be received as a result of the radio wave check, the control unit 1 immediately stops the reception circuit unit of the transmission / reception unit 2 and timer means (not shown) such as a timer built in the microcomputer. To count a predetermined intermittent reception interval. And the control part 1 will start the receiving circuit part of the transmission / reception part 2, if the count of the intermittent reception interval by the said timer means is completed, and will perform the above-mentioned radio wave check again. On the other hand, if it is determined that the radio signal can be received as a result of the radio wave check, the control unit 1 receives the radio signal as it is without stopping the reception circuit unit of the transmission / reception unit 2.

  As described above, when the fire does not occur (that is, always), the control unit 1 stops the reception circuit unit of the transmission / reception unit 2 during the counting of the intermittent reception interval by the timer unit, and counts the intermittent reception interval by the timer unit. Is completed, intermittent reception processing for starting up the receiving circuit unit of the transmitting / receiving unit 2 is performed. By the way, the intermittent reception interval is preferably shorter than twice the transmission period Tx, and is set to 4 seconds in the present embodiment.

  The fire occurrence notification process and the intermittent reception process described above are performed in common in the parent device side control unit 1A and the child device side control unit 1B, but the parent device side control unit 1A performs the fire occurrence notification process and the intermittent operation described above. In addition to the reception process, when the notification signal transmitted by the slave unit TR2 is received once by the transmission / reception unit 2, the end time prediction process for predicting the end time of the transmission period Tx during which the notification signal received by the transmission / reception unit 2 is transmitted And the interlocking instruction process which makes the transmission / reception part 2 start transmission of the notification signal to all the subunit | mobile_unit TR2 from the end of the transmission period Tx estimated by the said completion | finish prediction process.

  The end time prediction process is performed at the end of the transmission period Tx in which the notification signal is transmitted based on the number of continuous transmissions of the notification signal within the transmission period Tx and the serial number included in the notification signal received by the transmission / reception unit 2. Is a process for predicting. For example, in the present embodiment, the transmission period Tx is 2.8 seconds, and 100 ms is allocated to each of the notification signals. Therefore, the serial number of the received notification signal is 2 (within the transmission period Tx). 2nd notification signal), it is estimated that 2.6 seconds have elapsed from the completion of reception of the notification signal by the transmission / reception unit 2 as the end of the transmission period Tx.

  The interlock command process is performed after the end time of the transmission period Tx is predicted by the end time prediction process. In this interlocking instruction process, the master unit side control unit 1A activates the transmission circuit unit of the transmission / reception unit 2 in advance so that the notification signal can be transmitted from the predicted end time, and matches the predicted end time arrival. To start sending the notification signal. At this time, the master-side control unit 1A repeats the transmission operation and the reception operation a plurality of times alternately, similarly to the fire occurrence notification process. In the following description, in order to distinguish between the notification signal transmitted by the parent device TR1 and the notification signal transmitted by the child device TR2, the notification signal transmitted by the parent device TR1 is referred to as an interlock command signal as necessary. The notification signal transmitted by the slave unit TR2 is referred to as an interlock request signal.

  By the way, the subunit | mobile_unit side control part 1B will alert | report generation | occurrence | production of a fire by driving the speaker with which the alerting | reporting part 5 is provided, and making an alarm sound, if the transmission / reception part 2 receives a interlocking command signal. Furthermore, when the slave unit control unit 1B receives the interlock command signal by the transmission / reception unit 2, the slave unit control unit 1B causes the transmitter / receiver 2 to transmit a radio signal (link response signal) including a response message to the interlock command signal in the frame.

  In the case where the master unit side control unit 1A transmits the interlock command signal when the fire detection unit 4 detects the fire, it receives the interlock response signal from all the slave units TR2, or the interlock request signal from the slave unit TR2. When the interlock command signal is transmitted by receiving the interlock command signal when all slave units TR2 except the fire source slave unit (that is, the slave unit that transmitted the interlock request signal) TR2 is received. The process is terminated and the time division multiplex transmission process is started.

  In this time division multiplex transmission process, the parent control unit 1A causes the transmission / reception unit 2 to transmit beacons (synchronization signals, frame synchronization pulses) at a constant period. This beacon is a signal that defines a time slot necessary for performing time division multiplex transmission between fire alarms TR, and one period (cycle) is divided into a plurality of time slots (total number of fire alarms TR). Divided. When one time slot different from each other is assigned to each fire alarm device TR and a radio signal is transmitted, the control unit 1 of each fire alarm device TR stores and transmits it in the time slot assigned to its own station. By doing so, collision can be avoided. The time slot assignment for the fire alarm device TR may be fixed, but the time slot assignment information may be notified to each child device TR2 by a synchronization signal transmitted from the parent device TR1. Further, since a well-known method can be adopted as the time slot allocation method, detailed description is omitted.

  As described above, in the fire alarm system of the present embodiment, when no fire is detected by any of the fire alarms TR, each fire alarm TR transmits a radio signal asynchronously, and any of the fire alarms TR When a fire is detected, the parent device TR1 transmits a beacon with a fixed period, and each child device TR2 is assigned to a time slot defined by the beacon, and a radio signal is time-division multiplexed. As a result, when the frequency of transmitting wireless signals is low because there is no fire, the wireless signals are asynchronously transmitted to reduce power consumption and extend battery life. When it is sensed, that is, when the frequency of transmitting a radio signal becomes relatively high, the radio signal is time-division multiplexed to avoid collision and reduce information transmission delay.

  If a fire is not detected by the fire detection unit 4 of the fire alarm device TR or an operation input for stopping the ringing of the notification sound by the notification unit 5 is received, each fire is notified. Notification by the notification unit 5 ends in the alarm device TR. In this case, the parent device side control unit 1A of the parent device TR1 stops beacon transmission, whereby the fire alarm device TR returns to the normal intermittent reception operation (restarts the intermittent reception process) and becomes asynchronous.

  Next, the operation of the fire alarm system of this embodiment will be briefly described with reference to FIG. For example, when a fire occurs within the detection range of the fire detection unit 4 of the child unit TR2 (for example, child unit TR2A) (time T1 in FIG. 2), the occurrence of the fire is detected by the fire detection unit 4, The fire detection unit 4 notifies the slave side control unit 1B. Then, the child device (that is, the fire-source child device) TR <b> 2 </ b> A that has detected the fire notifies the fire occurrence by the notification unit 5. Further, the fire source child device TR2A transmits an interlock request signal to all the fire alarm devices TR other than itself (in this embodiment, the parent device TR1 and the child devices TR2B to TR2C).

  By the way, since the parent device TR1 and the child device TR2 are always asynchronously receiving intermittently, all the fire alarm devices TR are interlocked when the first transmission period Tx (Tx1) ends (time T2 in FIG. 2). The request signal cannot always be received.

  For example, in FIG. 2, the master unit TR1 and the slave unit TR2C are linked with each other because the intermittent reception period Ri in which the reception circuit unit of the transmission / reception unit 2 is activated overlaps the first transmission period Tx1 of the slave unit TR2A. Although the request signal can be received, the slave unit TR2B cannot receive the interlock request signal because the intermittent reception period Ri does not overlap with the first transmission period Tx of the slave unit TR2A.

  The master unit TR1 that has received the interlock request signal notifies the occurrence of a fire by the notification unit 5. The master unit TR1 executes an end prediction process to predict the end of the transmission period Tx1 (time T2 in FIG. 2), and starts transmitting the interlocking command signal from the predicted end.

  Thus, when the parent device TR1 starts transmitting the interlock command signal from the end of the transmission period Tx1, the notification signal (the interlock command signal in the master device TR1 and the interlock request signal in the slave device TR2). Is substantially doubled in the transmission period Tx during which is transmitted. Since the intermittent reception interval (4 seconds in the present embodiment) is shorter than twice the transmission period Tx (5.6 seconds in the present embodiment), the child device TR2B first receives the interlock command signal from the parent device TR1. The interlock command signal is received in the transmitted transmission period Tx (Tx2). And the subunit | mobile_unit TR2B which received the interlocking | linkage command signal alert | reports a fire occurrence by the alerting | reporting part 5. FIG. The slave unit TR2B transmits the interlock response signal at a predetermined timing, and shifts from the intermittent reception operation to the continuous reception operation.

  After transmitting the interlock request signal, the fire-source slave unit TR2A waits for reception of the interlock command signal. When receiving the interlock command signal, the slave unit TR2A stops transmitting the interlock request signal and shifts to the continuous reception operation. On the other hand, the slave unit TR2C that has received the interlock request signal transmitted from the fire source slave unit TR2A during the transmission period Tx1 notifies the occurrence of fire by the notification unit 5 and shifts from the intermittent reception operation to the continuous reception operation. Wait for reception of command signal. Thereafter, when receiving the interlock command signal, the slave unit TR2C transmits the interlock response signal at a predetermined timing.

  After transmitting the interlock command signal, master device TR1 determines whether or not the interlock response signal has been received from all slave devices TR2 (TR2B, TR2C) other than fire source slave device TR2A. When the master unit TR1 determines that the interlock response signal has been received from all the slave units TR2 other than the fire source slave unit TR2A, the master unit TR1 transmits a beacon including time slot allocation information to each slave unit TR2. Thereafter, the radio signal is time-division multiplexed and transmitted between the fire alarm devices TR (between the parent device TR1 and the plurality of child devices TR2).

  When a fire is no longer detected by the fire detection unit 4 of the master unit TR1 or when it is notified that an operation input for stopping the ringing of the notification sound by the notification unit 5 is received, each fire alarm The notification by the notification unit 5 ends in the device TR. Further, the master unit side control unit 1A of the master unit TR1 stops the transmission of the beacon, and thereby the fire alarm device TR returns to the normal intermittent reception operation.

  As described above, according to the fire alarm system of the present embodiment, when the fire detection unit 4 detects the occurrence of a fire, the transmission circuit unit of the transmission / reception unit 2 is activated and a notification signal is transmitted during a predetermined transmission period Tx. In addition, the transmission of the notification signal is suspended during a predetermined suspension period Rx, the transmission circuit unit of the transmission / reception unit 2 is stopped when a predetermined event has not occurred, and the transmission / reception unit 2 is counting the intermittent reception interval by the timer means. Since the reception circuit unit is activated every time the reception circuit unit is stopped and the counting of the intermittent reception interval by the timer means is completed, the power consumption of the fire alarm device TR can be reduced. Therefore, compared to the case where reception is always possible, the life of the battery constituting the power supply unit 6 can be extended, and for example, it can be used without maintenance for a long period of time such as several years. The frequency can be reduced and the maintainability can be improved.

  In addition, when the parent device TR1 receives the notification signal (link request signal) transmitted by the child device TR1, the master device TR1 ends the transmission period Tx (Tx1) when the received notification signal (link request signal) is transmitted ( Time T2) is predicted, and transmission of the notification signal (linked command signal) to all the child units TR is started from the predicted end time (time T2), so that the transmission period of the notification signal (linked request signal) of the child unit TR2 Since the time taken from the end of Tx (Tx1) to the start of transmission of the notification signal (linked command signal) by the parent device TR1 is shortened, the transmission period Tx of the notification signal is substantially doubled. From the start of transmission of the notification signal by the child unit TR2 to the end of the transmission of the notification signal by the parent unit TR1, the possibility of receiving the notification signal by the child unit TR2 receiving intermittently can be increased. As a result, information transmission delay It can be shortened between. In particular, in the present embodiment, since the intermittent reception interval is shorter than twice the transmission period Tx, the slave unit TR2 first starts transmitting the notification signal until the master unit TR1 finishes transmitting the notification signal. In addition, all the slave units TR2 that are intermittently receiving can receive the notification signal.

  Further, in the fire alarm system of the present embodiment, when the control unit 1 transmits the notification signal to the transmission / reception unit 2, the control signal is continuously transmitted a predetermined number of times within the transmission period Tx, and the frame of the notification signal includes: A serial number indicating what number was transmitted in the transmission period Tx is included. The master-side control unit 1A performs an end-time prediction process when the transmission / reception unit 2 receives the notification signal once. In the end-time prediction process, the number of continuous transmissions of the notification signal within the transmission period Tx and the transmission / reception unit 2 is predicted based on the serial number included in the notification signal received in step 2 when the notification signal is transmitted.

  As described above, in the fire alarm system of the present embodiment, if the transmission / reception unit 2 receives the notification signal even once, the master unit side control unit 1A starts the end time prediction process, so that the end time of the transmission period Tx has elapsed. It is highly possible that the end time can be predicted before the transmission, and the time taken from the end of the notification signal transmission period Tx of the slave unit TR2 to the start of transmission of the notification signal by the master unit TR1 can be shortened. .

  Further, the parent control unit 1A may perform the end time prediction process when the notification signal is received a plurality of times (for example, twice) instead of when the transmission / reception unit 2 receives the notification signal once. Good. In the end time prediction process in this case, the notification signal is generated based on the number of continuous transmissions of the notification signal within the transmission period Tx and the continuous transmission numbers included in a plurality of (for example, two) notification signals received by the transmission / reception unit 2. The end time of the transmitted transmission period Tx is predicted. More specifically, the master-side control unit 1A receives the notification signal received twice from the time when the reception of the notification signal received for the first time is completed and the time when the reception of the notification signal received for the second time is completed. Find the time interval. Then, the parent control unit 1A employs the obtained time interval as the time allocated to transmission of one notification signal, and performs prediction at the end.

  In this way, even if there is a deviation in the timer between the parent device TR1 and the child device TR2, the deviation of the timer or the like is detected from the time interval between the received notification signals, the transmission number, the number of transmissions, etc. Since the correction can be made, the reliability at the end of the transmission period Tx predicted by the end time prediction process can be improved.

  By the way, since the end time prediction process is a process for predicting the end time of the transmission period Tx from the received notification signal, the end time of the actual transmission period Tx and the end time of the predicted transmission period Tx are not necessarily the same. Not always. Here, when the end of the predicted transmission period Tx is before the actual end of the transmission period Tx, a notification signal (interlock request signal) transmitted by the slave unit TR2 and a notification signal transmitted by the master unit TR1 (Interlock command signal) may collide.

  Therefore, as shown in FIG. 4A, a guard signal (for example, all bit strings are set to 0 after the last notification signal (interlock request signal) continuously transmitted by the slave unit TR2 within the transmission period Tx). Bit example) G may be provided. Further, as shown in FIG. 4B, such a guard signal G may be provided before the first notification signal (interlocking command signal) that the master unit TR1 continuously transmits in the transmission period Tx. When provided before the first notification signal, the guard signal G may also be used in synchronization bit PR1 for time adjustment of the first notification signal.

  In addition, after the last notification signal (interlock request signal) that the slave unit TR2 continuously transmits in the transmission period Tx and before the first notification signal (link command signal) that the master unit TR1 continuously transmits in the transmission period Tx. You may provide the guard signal G in both. Note that the length of the guard signal G is preferably set as short as possible in view of the error in the prediction result of the end time prediction process.

  The fire alarm system of the present embodiment is merely an embodiment of the present invention, and is not intended to limit the technical scope of the present invention to that of the present embodiment, and does not depart from the spirit of the present invention. Naturally changes in range can be made.

1 (1A, 1B) Control unit (control means)
2 Transmission / reception unit (transmission means, reception means)
TR (TR1, TR2) Fire alarm (master unit, slave unit)

Claims (3)

A fire alarm system comprising a plurality of fire alarms,
Each fire alarm includes a fire detection means for detecting the occurrence of a fire, a transmission means for transmitting a wireless signal, a reception means for receiving a wireless signal, a timer means for repeatedly counting a certain intermittent reception interval, and a fire detection A notification means for notifying that the occurrence of a fire has been detected by the means, and a control means for controlling the transmission means and the reception means,
One of the multiple fire alarms is the master unit and the remaining fire alarms are the slave units.
When the fire detection means detects the occurrence of a fire, the control means activates the transmission means to transmit a notification signal including a radio signal including a notification message in a frame during a predetermined transmission period. Fire occurrence notification processing that repeatedly repeats the operation and the receiving operation that activates the receiving means and enables reception of a radio signal during a predetermined pause period,
When the fire detection means does not detect the occurrence of a fire, the reception means is stopped while the intermittent reception interval is counted by the timer means, and the reception means is started every time the intermittent reception interval is counted by the timer means. Process,
When the notification signal transmitted from the slave unit is received by the reception unit, the control unit of the master unit predicts the end of the transmission period during which the notification signal received by the reception unit is transmitted, and the end A fire alarm system characterized by performing linked command processing for starting transmission of a notification signal to all slave units from the end of a transmission period predicted by prediction processing. The control means, when causing the transmission means to transmit the notification signal, causes the notification signal to be continuously transmitted a predetermined number of times within the transmission period,
The frame of the notification signal includes a serial number indicating what number was transmitted in the transmission period,
The control unit of the parent device performs the end time prediction process when the notification signal is received once by the receiving unit,
In the end time prediction process, based on the number of continuous transmissions of the notification signal in the transmission period and the serial number included in the notification signal received by the receiving unit, the transmission period of the transmission period in which the notification signal is transmitted The fire alarm system according to claim 1, wherein an end time is predicted. The control means, when causing the transmission means to transmit the notification signal, causes the notification signal to be continuously transmitted a predetermined number of times within the transmission period,
The frame of the notification signal includes a serial number indicating what number was transmitted in the transmission period,
The control unit of the master unit performs the end time prediction process when the receiving unit receives the notification signal a plurality of times,
In the end prediction process, a transmission in which the notification signal is transmitted based on the number of continuous transmissions of the notification signal within the transmission period and the serial numbers included in the plurality of notification signals received by the receiving unit. The fire alarm system according to claim 1, wherein the end of the period is predicted.

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