JP5016264B2 - Wireless fire alarm system - Google Patents

Description

  The present invention relates to a wireless fire alarm system having a plurality of fire detectors for detecting a fire and a receiver for performing wireless communication using radio waves as a medium between the fire detectors.

  Conventionally, various fire alarm systems having a plurality of fire detectors for detecting a fire and a receiving device for receiving a fire detection signal transmitted in a wired manner from the fire detector that has detected a fire have been provided. On the other hand, wireless communication between the fire detector and the receiving device is performed because the wiring between the fire detector and the receiving device is not required when newly installed in existing facilities. A fire alarm system has been proposed (see, for example, Patent Document 1).

  On the other hand, in order to confirm that multiple fire detectors are operating normally in both wired and wireless communication systems, the receiving device periodically sends transmission requests to each fire detector. A message is transmitted, and a response message indicating the operating state of the fire detector is returned from each fire detector to the receiving device. Based on the response message, the receiving device determines whether or not a failure such as a battery exhaustion has occurred in each fire detector.

  Here, in order to improve the reliability of the fire alarm system, it is necessary to exchange the periodic transmission request message and the response message as described above as frequently as possible. For example, in the EN standard (European unified standard), a standard (EN54-25) that obligates the exchange of messages at a rate of once every 300 seconds is planned.

  By the way, periodic message exchanges are frequently performed as described above, and the more fire detectors included in the system, the higher the probability that collisions will occur due to overlapping transmission timings of the fire detectors. It is necessary to detect a collision and retransmit or avoid such a collision. For this reason, the one described in Patent Document 1 employs a carrier sense system that does not transmit a radio signal while a carrier used for radio communication is detected, and transmits a radio signal when no carrier is detected. ing.

  However, in the carrier sense method, since a certain time is required for switching between transmission / reception of the radio circuit, collision cannot be completely avoided. In addition, in a wireless fire alarm system, a frequency assigned to a radio station that does not require a license is generally used, but in some countries, a severe limitation is imposed on transmission time duty. For example, in the European Union, the transmission time duty must be less than 0.1% at the Alarm frequency used in the fire alarm system.

Therefore, in order to avoid signal collision and solve the transmission time duty limit, a fire alarm system has been proposed in which wireless communication between a receiver and a plurality of fire detectors is performed in a time division multiple access (TDMA) system. (For example, Japanese Patent Application No. 2005-168719). This fire alarm system is composed of one downstream time slot from the receiving device to the fire detector and a plurality of upstream time slots from the fire detector to the receiving device assigned to each fire detector. In the super frame in which a certain number of frames are collected, the receiving device and each fire detector exchange radio signals. Of the fixed number of frames that make up this superframe, the first frame is a periodic transmission frame for confirming the operating state of the fire detector, and the receiver receives a response signal from the fire detector in the downstream time slot. A periodic transmission signal for requesting is transmitted. On the other hand, when each fire detector receives the periodic transmission signal transmitted from the receiving device, it transmits a response signal indicating the operation state of the own device in the time slot assigned to the own device. The receiver knows the operating state of each fire detector. At this time, since each fire detector transmits a response signal in an upstream time slot assigned individually, collision of transmission signals from each fire detector can be avoided.
Japanese Patent No. 3029716 (pages 3 to 6 and FIGS. 1 to 7)

  In general, in TDMA wireless communication, a super frame starts with a timing signal transmitted from a base station as a starting point. Therefore, terminals newly participating in TDMA communication are synchronized with the base station. It is necessary to continuously set the wireless transmission / reception unit to the reception state until the timing signal transmitted from the terminal can be received. Even if the synchronization is lost for some reason during the system operation, it is necessary to continuously set the radio transmission / reception unit to the reception state until the timing signal from the base station can be received for resynchronization. When this is applied to the fire alarm system proposed in the above-mentioned Japanese Patent Application No. 2005-168719, the newly installed fire detector is synchronized with the receiver from the receiver in the first time slot of the superframe. It is necessary to receive a periodic transmission signal to be transmitted, and it is necessary to continuously receive a maximum of one super frame. In addition, even if the system is out of sync for some reason during system operation, it must be continuously received until the periodic transmission signal transmitted from the receiving device is received in the first time slot of the next superframe in order to resynchronize. Don't be. However, since the power source of the fire detector is a battery, if it continues to receive as described above, the battery is consumed violently and the battery must be replaced in a short period of time.

  The present invention has been made in view of the above problems, and its purpose is to provide wireless fire notification that can reduce power consumption when a fire detector is newly registered or resynchronized. To provide a system.

The invention of claim 1 has a plurality of fire detectors for detecting a fire, and a receiver for performing wireless communication using radio waves as a medium between the fire detectors. Sensing means for detecting a fire by detecting a temperature change and smoke generated, a first wireless transmitting / receiving means for transmitting and receiving a radio signal to and from the receiving device, and at least when a fire is detected by the sensing means A first control unit that controls the first wireless transmission / reception unit to transmit the fire detection information by a wireless signal, and the reception device includes a second wireless transmission / reception unit that transmits / receives a wireless signal to / from the fire detector; , and a second control means for obtaining fire information from the radio signal received by and controls the second radio transceiver means second wireless transmitting and receiving means, the first control means and second control means, One down direction from the receiver to the fire detector Wireless signals are exchanged in a superframe consisting of a fixed number of frames consisting of time slots and multiple upstream time slots from the fire detectors assigned to each fire detector to the receiver. In the wireless fire alarm system, the first control means of the fire detector which is not synchronized controls the first wireless transmission / reception means to the receiver until the first time slot of the next superframe. A synchronization request signal for requesting synchronization information including at least the number of time slots is transmitted, and the second control means of the receiving device receives the second wireless transmission means when the second wireless transmission / reception means receives the synchronization request signal from the fire detector. by controlling the transmission and reception means, immediately after receiving regardless uplink and downlink time slots, transmits a synchronization request signal to the synchronization reply signal including the synchronization information Was sent to the fire detector, the first control means transmits a synchronization request signal fire detector, when the first wireless transmitting and receiving means receives the synchronization reply signal, based on the synchronization information included in the synchronization response signal At least the number of time slots is counted, and when the counting is completed, the first wireless transmission / reception unit is set in a reception state so that the first time slot of the next superframe can be received, and transmitted from the second wireless transmission / reception unit in the first time slot Receiving a radio signal .

The invention of claim 2 is characterized in that the synchronization information includes the number of bits from the next bit after transmission of the synchronization reply signal to the next time slot together with the number of time slots .

  According to the invention of claim 1, when the fire detector transmits a synchronization request signal requesting synchronization information to the receiving device, the receiving device receives the synchronization request signal from the fire detector immediately after receiving the synchronization request signal. Is transmitted to the fire sensor, the fire sensor can receive the synchronization reply signal in a short time, and the power consumption can be reduced. In addition, when registering a new fire detector at the time of system construction or resynchronizing an out-of-sync fire detector, it is possible to reliably synchronize with the receiving device by using the received synchronization information There is.

Furthermore , since the synchronization information included in the synchronization reply signal transmitted from the receiving device includes at least the number of time slots up to the first time slot of the next superframe, the fire detector counts the number of received time slots. Thus, the start time of the first time slot of the next superframe can be grasped by the time width of one time slot. Therefore, if the fire detector receives two time slots after counting the number of time slots, the first time slot of the next superframe can be reliably received. Since the power supply to the wireless transmission / reception means can be stopped from the time when the synchronization reply signal of the receiving apparatus is received until the reception of two time slots after counting the number of time slots, the power consumption is reduced. There is an effect that can be.

According to the invention of claim 2, the synchronization information included in the synchronization reply signal transmitted from the receiving device includes the number of bits from the next bit after the synchronization reply signal transmission to the next time slot together with the number of time slots. Therefore, the fire detector can more accurately grasp the start time of the first time slot of the next superframe with the time width of one bit by counting the number of received time slots and the number of bits. Therefore, the first time slot of the next superframe can be reliably received only by receiving one time slot after counting the number of time slots and the number of bits in the fire detector. Since the power supply to the wireless transmission / reception means can be stopped from the time the reception of the synchronization reply signal to the reception of one time slot after counting the number of timeslots and the number of bits, further battery consumption There is an effect that can be suppressed.

(First embodiment)
A first embodiment of the present invention will be described below with reference to FIGS.

  The wireless fire alarm system according to the present invention includes one receiver 1 and a plurality of fire detectors 6.

Each fire detector 6 is installed on the ceiling of a facility, for example, and includes a sensing unit 7 that senses a fire by detecting temperature change or smoke generated by the fire, or both temperature change and smoke. And a radio transmission unit 9 that modulates data into a carrier wave having a prescribed frequency and transmits the radio signal as a radio signal to the reception device 1; and a radio signal transmitted from the reception device 1 as a medium. A wireless receiver 8 that demodulates the received signal into data, and a controller (first control) that controls the wireless receiver 8 and the wireless transmitter 9 to transmit fire detection information and a synchronization request signal described later by wireless signals. Means) 10, sensing unit 7, wireless receiving unit 8, wireless transmitting unit 9, battery 12 for supplying operation power to control unit 10, antenna 11 for transmitting and receiving wireless signals, and under control of control unit 10 Wirelessly from battery 12 And a switch 13 that individually opens and closes a power feeding path to the transmission unit 8 and the wireless transmission unit 9 (see FIG. 2A). The wireless receiving unit 8 and the wireless transmitting unit 9 constitute a first wireless transmission / reception means . The control unit 10 includes a microcomputer and a nonvolatile memory such as an EEPROM as main components, and executes various processes by executing a program stored in the nonvolatile memory. Each fire detector 6 is given a unique address at the time of manufacture or construction and is stored in the nonvolatile memory of the control unit 10.

On the other hand, the receiving device 1 is installed in a management room of a facility, for example, and modulates data into a carrier wave having a specified frequency and transmits the data to the fire detector 6 as a radio signal using radio waves as a medium. The wireless receiver 2 that receives the radio signal using the radio wave transmitted from the fire detector 6 as a medium and demodulates the received signal into data, and controls the wireless receiver 2 and the wireless transmitter 3 A control unit (second control means) 4 that transmits a synchronization reply signal, which will be described later, by a radio signal, and an antenna 5 for transmitting and receiving the radio signal are provided (see FIG. 2B). The wireless receiving unit 2 and the wireless transmitting unit 3 constitute a second wireless transmission / reception means . The control unit 4 includes a microcomputer and a nonvolatile memory such as an EEPROM as main components, and executes various processes by executing a program stored in the nonvolatile memory. The receiving device 1 is given a unique address different from that of the fire detector 6 at the time of manufacture or construction and is stored in the nonvolatile memory of the control unit 4.

  By the way, in this embodiment, the radio | wireless communication between the receiver 1 and the some fire detector 6 is performed by a time division multiple access (TDMA) system. That is, as shown in FIG. 1 (a), a time slot B of one downstream direction (receiving device 1 → fire detector 6) and a plurality of time slots A1 to A1 of the upstream direction (fire detector 6 → receiving device 1). Each frame F1 to Fm is composed of An, and a certain number of frames F1 to Fm are collected to form a superframe SF. Then, by assigning the upstream time slots A1 to An in each frame F1 to Fm to each fire detector 6 individually, the interval between periodic signal exchanges (periodic transmission signal and response signal exchange) is relatively short. In this case, for example, even in the case of once in 300 seconds in the EN standard, it is possible to reliably avoid a collision between radio signals transmitted from the fire detector 6. Here, the time slots A1 to An assigned to each fire detector 6 are set by, for example, a dip switch provided in the control unit 10, stored in advance in the nonvolatile memory of the control unit 10 in the manufacturing process, or at the time of installation. What is necessary is just to perform by the method of assigning to each fire detector 6 from the receiver 1 in order using wireless communication, and storing in the non-volatile memory of the control part 10.

  Next, when a new fire detector 6 is registered at the time of system construction, or during the operation of the system, for example, the fire detector 6 transmits a radio signal from the receiving device 1 transmitted in the downstream time slot B several times. The operation when it is detected that synchronization has been lost due to the inability to receive data and the receiver 1 is requested to perform resynchronization will be described with reference to the time chart of FIG. 1B and the flowchart of FIG. . First, it is assumed that the receiving apparatus 1 is always in the receiving state except for the time slot B in the downlink direction, and the receiving apparatus 1 is in the receiving state (S1 in FIG. 3). When the receiving device 1 is not in the receiving state, it cannot receive a synchronization request signal described later from the fire detector 6, so that the fire detector 6 receives a response signal corresponding to the synchronization request signal. I can't. Therefore, in this case, it is only necessary to notify that the synchronization has failed by blinking an LED or the like provided on the fire detector 6.

  Since the newly registered fire detector 6 or the control unit 10 of the fire detector 6 out of synchronization does not grasp the position of the time slot, any time when synchronization is required (FIG. 1 (b At time t1), the control unit 10 switches the switch 13 to supply power to the wireless transmission unit 9 so that the wireless transmission unit 9 is in a transmission state. Then, the control unit 10 controls the wireless transmission unit 9 to transmit a synchronization request signal for requesting synchronization information to the receiving device 1 regardless of the time slot position (S2 in FIG. 3). The synchronization information is time information up to the first time slot B of the next super frame SF, and in this embodiment, the synchronization information is the number of time slots up to the first time slot B of the next super frame SF. When the synchronization request signal is transmitted, the control unit 10 switches the switch 13 to cut off the power supply to the wireless transmission unit 9 to stop the transmission of the wireless transmission unit 9 and supply power to the wireless reception unit 8 to perform wireless reception. The unit 8 is set in the receiving state. On the other hand, the control unit 4 of the receiving device 1 controls the wireless transmission unit 3 and transmits the synchronization request signal as soon as the wireless reception unit 2 receives the synchronization request signal at time t1 (S3 in FIG. 3). A synchronization reply signal including the number of time slots up to the first time slot B of the next superframe SF as synchronization information is sent to the sensor 6 regardless of the time slot position at time t2, as shown in FIG. Transmit (S4 in FIG. 3). And the control part 10 of the fire detector 6 controls the radio | wireless receiving part 8, and receives the synchronous reply signal transmitted from the receiver 1 in time t2 (S5 of FIG. 3). When the synchronization reply signal is received, the control unit 10 switches the switch 13 to cut off the power supply to the wireless reception unit 8 and stops the reception of the wireless reception unit 8. Then, the control unit 10 starts an internal timer (not shown) that counts the number of time slots up to the first time slot B of the next superframe SF included in the synchronization reply signal (S6 in FIG. 3). When the time t3 has elapsed and the internal timer finishes counting the number of time slots (S7 in FIG. 3), the control unit 10 switches the switch 13 to supply power to the wireless reception unit 8, and the wireless reception unit 8 is in a reception state. Then, as shown in FIG. 1 (b), two time slots are received (S8 in FIG. 3). When receiving two time slots, the control unit 10 switches the switch 13 to cut off the power supply to the wireless reception unit 8 and stops the reception of the wireless reception unit 8.

  Since the receiving device 1 returns the synchronization request signal from the fire detector 6 immediately after receiving it, the fire detector 6 can receive the synchronization reply signal by the next time slot at the latest. Then, by counting the number of received time slots, the start time of the first time slot B of the next superframe SF can be grasped by the time width of one time slot. The first time slot B of the superframe SF can be reliably received. As a result, the fire detector 6 can be synchronized with the receiving device 1 (S9 in FIG. 3). Further, the control unit 10 of the fire detector 6 does not need to receive a radio signal after receiving the synchronization reply signal of the receiving device 1 and receiving two time slots after counting the number of time slots. The receiving unit 8 does not have to be in a receiving state, and power supply to the wireless receiving unit 8 can be stopped while not receiving, so that battery consumption can be suppressed. When synchronization with the receiving apparatus 1 is established, for subsequent wireless communication, a wireless signal such as a periodic transmission signal is transmitted in the time slot An assigned to itself (S10 in FIG. 3).

  By the way, in this fire alarm system, for example, when the time slot length is 100 ms and the super frame length is 300 s, if the number of fire detectors 6 is up to three, the transmission time duty specified in the European standard is 0.1%. Can be satisfied.

  The receiving device 1 may be provided with a display unit for displaying fire detection information or abnormality information generated in any one of the fire detectors 6 and a notification unit by voice. In addition, a fire alarm panel provided with a display unit and an alarm unit may be provided separately, and the communication means between the receiving device 1 and the fire alarm panel may be either wireless or wired. Furthermore, the number of fire detectors 6 that perform wireless communication with the receiving device 1 may be any number that satisfies the transmission time duty 0.1% defined in the European standard. The battery used for the fire detector 6 may be either a primary battery or a secondary battery.

(Second Embodiment)
A second embodiment will be described based on FIG. 1, FIG. 2, and FIG. Since the configuration other than the configuration including the number of bits as well as the number of time slots as the synchronization information in the synchronization reply signal is the same as in the first embodiment, the same components are denoted by the same reference numerals and description thereof is omitted. .

  In the wireless fire alarm system according to the present embodiment, the synchronization reply signal of the receiver 1 in response to the synchronization request signal of the fire detector 6 is transmitted together with the number of time slots up to the first time slot B of the next superframe SF, after the synchronization reply signal is transmitted. The number of bits from the next bit to the next time slot is included. Other configurations are the same as those in the first embodiment.

  Here, when the fire detector 6 is newly registered at the time of system construction, or when the fire detector 6 out of synchronization for some reason during system operation requests the receiver 1 to re-synchronize, This will be described based on the flowchart of FIG. First, it is assumed that the receiving apparatus 1 is always in the receiving state except for the time slot B in the downlink direction, and the receiving apparatus 1 is in the receiving state (S1 in FIG. 4). Note that the case where the receiving device 1 is not in the receiving state has been described in the first embodiment, and thus the description thereof is omitted here.

  The control unit 10 of the newly registered fire detector 6 or the out-of-synchronization fire detector 6 does not grasp the position of the time slot, so the switch 13 is switched at any time when synchronization is required. Then, power is supplied to the wireless transmission unit 9 to put the wireless transmission unit 9 in a transmission state. Then, the control unit 10 controls the wireless transmission unit 9 to transmit the synchronization request signal to the reception device 1 regardless of the time slot position (S2 in FIG. 4). When the synchronization request signal is transmitted, the control unit 10 switches the switch 13 to cut off the power to the wireless transmission unit 9 to stop the transmission of the wireless transmission unit 9 and supply power to the wireless reception unit 8 to supply the wireless reception unit. 8 is set to the reception state. On the other hand, as soon as the wireless receiver 2 receives the synchronization request signal (S3 in FIG. 4), the control unit 4 of the receiving device 1 controls the wireless transmitter 3 to transmit the fire detector 6 that has transmitted the synchronization request signal. On the other hand, the number of bits from the next bit to the next time slot after the transmission of the synchronous reply signal (the time of FIG. 1B) together with the number of time slots up to the first time slot B of the next superframe SF as the synchronization information A synchronization reply signal including the time slot 4 is transmitted regardless of the time slot position (S4 in FIG. 4). And the control part 10 of the fire detector 6 controls the radio | wireless receiving part 8, and receives the synchronous reply signal transmitted from the receiver 1 (S5 of FIG. 4). When the synchronization reply signal is received, the control unit 10 switches the switch 13 to cut off the power supply to the wireless reception unit 8 and stops the reception of the wireless reception unit 8. Then, the control unit 10 starts an internal timer for counting the number of time slots and the number of bits included in the synchronization reply signal (S6 in FIG. 4), and when the internal timer finishes counting the number of time slots and the number of bits ( In step S7 in FIG. 4, the control unit 10 switches the switch 13 to supply power to the wireless reception unit 8, sets the wireless reception unit 8 in a reception state, and receives one time slot (step S8 in FIG. 4). When receiving one time slot, the control unit 10 switches the switch 13 to cut off the power supply to the wireless reception unit 8 and stops the reception of the wireless reception unit 8.

  Since the receiving device 1 returns the synchronization request signal from the fire detector 6 immediately after receiving it, the fire detector 6 can receive the synchronization reply signal by the next time slot at the latest. Then, by counting the number of received time slots and the number of bits, the start time of the first time slot B of the next superframe SF can be grasped by the time width of one bit. Thus, the first time slot B of the next super frame SF can be received reliably. As a result, the fire detector 6 can be synchronized with the receiving device 1 (S9 in FIG. 4). Further, the control unit 10 of the fire detector 6 does not need to receive a radio signal after receiving the synchronization reply signal from the receiving device 1 until receiving one time slot after counting the number of time slots and the number of bits. Therefore, the wireless receiving unit 8 does not have to be in a receiving state, and the power supply to the wireless receiving unit 8 can be stopped while not receiving, thereby further reducing battery consumption compared to the first embodiment. it can. When synchronization with the receiving apparatus 1 is established, a wireless signal such as a periodic transmission signal is transmitted in the time slot An assigned to itself for subsequent wireless communication (S10 in FIG. 4).

  In the present embodiment, as the synchronization reply signal of the receiving device 1 with respect to the synchronization request signal of the fire alarm 6, together with the number of time slots up to the first time slot B of the next superframe SF, the next after transmission of the synchronization transmission signal Although the number of bits from the bit to the next time slot is transmitted, only the number of bits from the next bit after the transmission of the synchronous reply signal to the first time slot B of the next superframe SF may be transmitted. It is not limited to the embodiment.

(A) is a block diagram of a super frame in the first embodiment. (B) is a timing chart for explaining the exchange of signals when synchronizing the fire detector with the receiving device. (A) is a block diagram of the fire detector in the same as the above. (B) is a block diagram of the receiving apparatus in the above. It is a flowchart for demonstrating the operation | movement at the time of synchronizing the fire detector with a receiver in the same as the above. It is a flowchart for demonstrating the operation | movement at the time of synchronizing the fire detector in 2nd Embodiment with a receiver.

Explanation of symbols

1 Receiving Device 2 Wireless Reception Unit (Wireless Transmission / Reception Unit)
3 Wireless transmission part (wireless transmission / reception means)
4 Control unit (control means)
6 Fire detector 7 Sensing part (sensing means)
8 Wireless receiver (wireless transmission / reception means)
9 Wireless transmitter (wireless transmitter / receiver)
10 Control unit (control means)

Claims (2)

A plurality of fire detectors for detecting a fire, and a receiver for performing wireless communication using radio waves as a medium between the fire detectors;
The fire detector includes a sensing means for sensing a fire by detecting a temperature change and smoke generated by a fire, a first wireless transmission / reception means for transmitting / receiving a wireless signal to / from the receiving device, and at least First control means for controlling the first wireless transmission / reception means to transmit fire detection information by a wireless signal when a fire is detected by the detection means;
The receiver, from the radio signal received by the second and the wireless transceiver means, and controlling the second wireless transceiver unit and the second radio transceiver means for transmitting and receiving radio signals to and from the fire detector Second control means for obtaining fire detection information;
The first control means and the second control means include one downstream time slot from the receiving device to the fire sensor, and from the fire sensor assigned to each fire sensor. A wireless fire alarm system for transmitting and receiving radio signals in a superframe in which a fixed number of frames composed of a plurality of uplink time slots to a receiving device are collected,
The first control means of the fire detector that is not synchronized controls the first wireless transmission / reception means to determine the number of time slots until the first time slot of the next superframe for the receiving device. Sending a synchronization request signal requesting synchronization information including at least,
The second control means of the receiving device controls the second wireless transmission / reception means when the second wireless transmission / reception means receives the synchronization request signal from the fire detector, and controls the upward and downward directions. Immediately after reception regardless of the time slot, a synchronization reply signal including the synchronization information is transmitted to the fire detector that has transmitted the synchronization request signal ,
The first control unit of the fire detector that has transmitted the synchronization request signal receives at least the synchronization information included in the synchronization reply signal when the first wireless transmission / reception unit receives the synchronization reply signal. Counting the number of time slots, and when the counting is completed, sets the first wireless transmission / reception means in a receiving state so that the first time slot of the next superframe can be received, and the second wireless transmission / reception means at the first time slot. A wireless fire alarm system characterized in that it receives a radio signal transmitted from . The wireless fire alarm system according to claim 1 , wherein the synchronization information includes the number of bits from the next bit after transmission of the synchronization reply signal to the next time slot together with the number of time slots .

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