JP5671166B2 - Fire alarm system - Google Patents

Description

The present invention relates to a fire alarm system in which a plurality of fire detectors are connected to a sensor line drawn from a receiver, and fire alarms are received and alarmed on a line basis.

  Conventionally, in the fire alarm system known as P type, a plurality of fire detectors are connected to the sensor line drawn from the receiver, and the alarm signal from the fire detector is received for each line. The fire is alarmed.

  On the other hand, in the fire alarm system known as the R type, a terminal device such as a repeater or an analog fire detector having a transmission function is connected to the transmission line drawn from the receiver, and when a fire is detected, For example, based on a fire interrupt from a terminal device, issue a search command to identify the address of the terminal device that was issued, display the fire occurrence address, and collect and monitor fire data from the identified terminal device. ing.

  Thus, knowing the address of the fire detector or repeater that detected the fire makes it possible to conduct appropriate evacuation guidance and fire extinguishing activities, and is an indispensable function especially for large-scale facility fire monitoring.

  However, in the P-type fire alarm system, the receiver knows which sensor line has fired, but which sensor out of the multiple sensors connected to the alarm line that has fired has fired. I don't know if I reported it.

  Therefore, in recent years, the P-type fire alarm system is also able to identify the fire detector that has been notified by transmitting an address signal from the fire detector that has issued the alarm. FIG. 8 is a time chart of the detector line voltage and the fire detector switching circuit when a fire is triggered in the conventional P-type fire alarm system.

  Among a plurality of fire detectors connected to the same sensor line, for example, address No. If the fire detector set to 3 detects a fire at time t1 and issues a fire alarm, it turns on the switching circuit provided in the fire detector that triggered the alarm to generate a fire signal common to the sensor lines. For this reason, as shown in FIG. 8A, the voltage of the sensor line is lowered from 24 V at the time of monitoring to 10 V, for example.

  Subsequently, as shown in FIG. 8 (B), the fire detector that has been issued reports the address No. of the switching circuit. The address signal is transmitted by a switching operation indicating 3 so that the sensor line voltage changes between 10V and 24V as shown in FIG.

  In the receiver, the address No. that fired at time t1 was detected. The common fire signal transmitted from the fire detector 3, that is, a voltage drop of the sensor line is detected and an alarm is issued, and the address signal received after the fire common signal, that is, the voltage change of the sensor line is detected. Identify the address of the fire detector that issued the alarm, and display necessary information such as the area where the fire occurred.

JP 2001-184571 A JP 2004-38647 A JP 2005-352919 A Japanese Patent Laid-Open No. 9-180072 JP-A-62-109196

  However, in such a conventional P-type fire alarm system in which an address signal is transmitted in addition to a common fire signal from the fire alarm that has reported, the first report that fired first Although it is possible to specify a fire detector, it is not possible to specify a fire detector for the second and subsequent reports issued by other fire detectors connected to the same detector line. There's a problem.

SUMMARY OF THE INVENTION An object of the present invention is to provide a P-type fire alarm system that can identify fire detectors that are issued after the second report connected to the same sensor line.

In order to achieve this object, the present invention is configured as follows. The present invention relates to a fire alarm system including a receiver for notifying a fire based on a voltage change between sensor line terminals due to a change in current flowing in a sensor line connected to a plurality of fire detectors.
When a fire detector detects a fire and issues a fire, it generates a first voltage change between the sensor line terminals, and sends a common fire signal to the multiple fire detectors to the receiver. An alarm control unit for generating a second voltage change between the sensor line terminals and transmitting a different address signal for each of the plurality of fire detectors to the receiver;
The receiver
The fire detector and the address signal are received, and the number of fire detectors to be reported is determined from the first voltage change during the time period when the address signal is not received after receiving the fire signal, and the determined fire detector The number of fire alarms and the number of fire alarms identified by the received address signal are compared, and if they match, a fire alarm is output and the fire alarm identification information is output, not matching In this case, a reception control unit that outputs an address signal reception failure report;
A display unit capable of displaying a fire alarm, identification information and reception failure report;
With
The first voltage change is a steady change that is a predetermined voltage drop with respect to the voltage between the terminals of the sensor line in a normal state.
The second voltage drop is a pulse change based on the address signal from the alarm control unit,
The alarm control unit transmits the address signal to the receiver in a time zone in which there is no second voltage change between the sensor line terminals after transmitting the fire signal.

  Here, when all the fire detectors connected to the sensor line transmit a fire signal, the total voltage change including the first voltage change and the second voltage change is the normal sensor line. The voltage across the terminals of the sensor line when the total voltage changes is made higher than the minimum operating voltage of the fire detector.

  The notification control unit repeatedly transmits an address signal.

  In addition, the reception control unit outputs a fire alarm together with a reception failure report when the number of fire detectors that are not in correspondence with each other.

In addition, the reception control unit identifies the number of fire detectors to be reported based on the address signal received within a predetermined time after receiving the last fire signal.

  According to the present invention, the fire detector generates a predetermined voltage drop in the sensor line and transmits a fire signal, and at the timing when there is no pulse change in the voltage between the terminals of the sensor line, Even if multiple fire detectors connected to the same sensor line are triggered by generating a voltage change and transmitting their own address signal, the receiver can identify the fire detector that triggered the alarm. Can do.

  In addition, when each of the fire detectors generates a voltage drop and transmits a fire signal, when multiple fire detectors connected to the same detector line are informed, the receiver has issued an alarm. Even when any of the fire detectors fails to be identified, the number of fire detectors that have been reported can be known from the amount of change in the voltage of the detector line caused by a plurality of fire signals.

  In addition, all the fire detectors connected to the sensor line transmit a fire signal, and any one of the fire detectors transmits an address signal. By selecting the voltage change amount of the fire signal and the address signal so as to be higher than the minimum operating voltage of the fire detector, it is possible to prevent the fire detector from being stopped.

Furthermore, if the number of fire detectors determined by the amount of voltage change in the sensor line due to the fire signal does not match the number of fire detectors identified by the received address signal, the address signal is received. By displaying the failure report, the receiver can warn of a system failure, for example, when checking the fire notification system.

Explanatory drawing of the fire alarm system to which the present invention is applied Explanatory drawing of embodiment of the fire detector of FIG. Explanatory diagram showing a fire alarm control function according to the present invention by taking out one of the sensor lines of FIG. Time chart showing the transmission operation of the fire signal and address signal at the time of fire alarm in FIG. Time chart when address signal transmission is repeated in FIG. The flowchart which showed the alarm control processing by the fire detector of FIG. The flowchart which showed the reception control processing by the receiver of FIG. Time chart of alarm control in a conventional fire alarm system

  FIG. 1 is an explanatory diagram of a fire alarm system according to the present invention. In FIG. 1, sensor lines 12-1, 12-2,..., 12 -m are drawn from the receiver 10. 1-No. The n fire detectors 14 having the addresses indicated by n are connected together with the terminating resistor 16. As the fire sensor 14 connected to the sensor lines 12-1 to 12-m, various fire sensors such as a smoke sensor and a heat sensor can be connected.

  The receiver 10 is provided with an MPU 18. An operation unit 22, an alarm display unit 24, a district display unit 26, a transfer output unit 28, and a memory 30 are provided for the MPU 18. Further, on the sensor line side of the MPU 18, receiving circuit units 20-1, 20-2,... 20-m are provided for each line, and are detected by the receiving circuit units 20-1 to 20-m. Device lines 12-1 to 12-m are drawn out.

  The receiving circuit units 20-1 to 20-m receive the fire signal by the fire alarm of the fire sensor 14 connected to the sensor lines 12-1 to 12-m, and are transmitted following the fire signal. Receive an address signal.

  The reception control unit 32 provided in the MPU 18 of the receiver 10 sequentially reads reception signals from the reception circuit units 20-1 to 20-m, discriminates a fire signal for each sensor line, and displays an alarm, that is, a fire representative display. And district display (report line display). In addition, the address of the detector that has been issued is identified from the address signal received following the fire signal, and the address or district name of the fire detector that has been issued separately in the district display section for the first and second reports. Is displayed.

  FIG. 2 is an embodiment of the fire detector 14 of FIG. 1, taking a scattered light smoke detector as an example. In FIG. 2, the fire detector 14 includes a rectifier circuit / noise absorbing circuit 34, a first switching circuit 38, a second switching circuit 40, a constant voltage / current limiting circuit 42, an operation indicator 44, an address setting circuit 46, an alarm. The control unit 48, the oscillation circuit 50, the light emitting element 52, the light receiving element 54, the amplification circuit 56, and the comparison circuit 58 are configured.

  Here, the rectifier circuit / noise absorbing circuit 34 makes the current between the lines L-C nonpolar by, for example, a diode bridge, a Zener diode, a capacitor, etc., and further suppresses noise. The constant voltage / current limiting circuit 42 limits the supply current to the subsequent circuit unit to a constant value in order to prevent a transient current on the line L-C.

  During normal monitoring, the light emitting element 52 is pulse-driven by the oscillation circuit 50 and periodically emits light. When smoke is generated by a fire, light from the light emitting element 52 is scattered by the smoke and enters the light receiving element 54. The incident light is converted into a photocurrent, and after being amplified by the amplifier circuit 56, the signal is input to the comparison circuit 58.

  When this signal exceeds the specified value, the alarm control unit 48 counts in synchronization with the light emission cycle of the light emitting element 52, and when the predetermined count is reached, the fire alarm signal is sent to the first switching circuit 38. Then, based on the address code set by the address setting circuit 46, a pulsed address signal is output to the second switching circuit 40.

  That is, the alarm control unit 48 is constituted by a CPU, monitors the signal state of the sensor line by taking in a signal from the input side of the constant voltage / current limiting circuit 42, and receives a fire detection signal from the comparison circuit 58. A fire alarm signal is output to the first switching circuit 38, and a pulse change due to the address signal is output to the second switching circuit 40 in a time zone in which there is no pulse change in the signal state of the sensor line.

  The first switching circuit 38 performs switching based on the fire alarm signal from the alarm controller 48 and causes a current change between the lines L-C to generate a voltage change that is a steady change in the sensor line 12. A common fire signal is transmitted to the fire detector 14 connected to the sensor line 12. This voltage change is a predetermined voltage drop with respect to the voltage across the terminals of the sensor line 12 during normal monitoring.

  The second switching circuit 40 performs switching based on the address signal from the alarm control unit 48 and causes a voltage change, which is a pulse change, to occur in the detector line 12 by causing a current to flow between the lines L-C. A different address signal is transmitted for each device 14.

  The first switching circuit 38 passes a constant current, for example, a current of 10 milliamperes, which is set in a range of 5 to 30 milliamperes as a common fire signal, between the lines L-C. The second switching circuit 40 causes a current change of, for example, 20 milliamperes when the address signal is switched on / off. Also, the alarm control unit 48 turns on the operation indicator lamp 44 at the same time as the fire alarm.

  FIG. 3 is an explanatory diagram showing a fire alarm control function according to the present invention by taking out one of the sensor lines 12-1 to 12-m of FIG. In FIG. 3, the sensor line 12 drawn from the receiving circuit unit 20 of the receiver 10 has a No. 1-No. A fire detector 14 having an n number as an address is connected.

  The fire detector 14 takes out a part of the first switching circuit 38 and the second switching 40 that are controlled to be turned on / off by the alarm control unit 48, and the first switching circuit 38 has a resistance between the sensor lines 12. R1 and the transistor Q1 are connected in series, and the second switching circuit 40 also has a resistor R2 and a transistor Q2 connected in series between the sensor lines 12.

  Here, all the fire detectors 14 connected to the sensor line 12 turn on the first switching circuit 38 to cause the current I1 to flow between the sensor lines 12 as a fire signal transmission. Any one of the fire detectors 14 connected to the sensor line 12 in the state where the second switching 40 is turned on / off and the current I2 flows between the sensor lines 12 as an address signal transmission. The resistance R1 of the first switching circuit 38 and the second switching circuit are set so that the total voltage change of the first switching circuit 38 is smaller than the terminal voltage at the time of normal monitoring and the terminal voltage at that time is higher than the minimum operating voltage of the fire detector 14. Forty resistors R2 are selected.

  FIG. 4 is a time chart showing the transmission operation of the fire signal and the address signal at the time of the fire alert in FIG. Fire alarm No. 1 is triggered, and address No. 2 followed by address No. The case where n fire detectors have issued the third report is taken as an example.

  4A shows the sensor line voltage, and FIG. 1 is the ON / OFF state of the transistor Q1 of the first switching circuit 38 in FIG. The transistor Q2 of the second switching circuit 40 in the first fire detector 14 is turned on / off.

  FIG. 4D shows an address number. 2 is the on / off state of the transistor Q1 of the first switching circuit 38, and FIG. 2 shows ON / OFF of the transistor Q2 in the second switching circuit 40 of the second fire detector 14.

  Further, FIG. n is the on / off state of the transistor Q1 of the first switching circuit 38 in the fire detector 14, and FIG. The on / off state of the transistor Q2 in the second switching circuit 40 of the n fire detectors 14 is shown.

  In FIG. 4, if a fire occurs at time t1, the fire is detected, and an address No. 1 is displayed as shown in FIG. The transistor Q1 provided in the first switching circuit 38 of one fire detector 14 is turned on, and a current I1 as a fire signal is caused to flow through the detector line 12. For this reason, the sensor line voltage is decreased from 24 V during normal monitoring to v1.

  Address No. issued at time t1. As shown in FIG. 4C, the fire detector 14 of FIG. 1 turns on / off the transistor Q2 of the second switching circuit 40 at a time t3 after a certain time has passed since the alarm is issued. A current I2 serving as an address signal for the first report according to an address signal indicating 1 is supplied.

  This address signal is transmitted by turning on / off the transistor Q2 with the current I1 as a fire signal flowing through the sensing line 12, so that the current in the sensor line 12 is the current (I1 + I2) when the transistor Q2 is on. Current increase and decrease. Correspondingly, the sensor line voltage shown in FIG. 4 (A) decreases when the transistor Q2 is turned on, and increases when the transistor Q2 is turned off.

  Address No. As shown in FIG. 4D, the fire detector 14 of No. 2 detects and issues a fire at time t2 following the fire occurrence time t1, and turns on the transistor Q1 of the first switching circuit 38. Then, the current I1 is passed through the sensing line 12 as a fire signal.

  For this reason, the address No. 2 at the time t2 when the fire detector 14 issued, Since the first fire detector 14 issues the first fire, a current (2 × I1) that is the sum of the first and second reports flows through the detector circuit 12 as a fire signal.

  The address No. 1-No. Since the resistance value of the resistor R1 is the same, the fire detector 14 of n has a detector for the first current I1 that turns on the transistor Q1 when the voltage of the sensor line 12 is 24V during normal monitoring. The current I1 of the second report that turns on the transistor Q1 when the voltage of the line 12 is lower than that at the time of normal monitoring by the first report is slightly smaller. However, in this embodiment, 2 The same current I1 is used for the reports.

  Further, as will be clarified later, in the identification of the number of alarms when a plurality of fire detectors 14 transmit a fire signal, the number of alarms is determined based on the voltage change amount of the sensor line 12. Therefore, there is no practical problem even if the value of the current I1 flowing through each fire detector 14 at the time of reporting is not strictly distinguished.

  Corresponding to the second report, the sensor line voltage shown in FIG. 4A decreases from v1 due to the first fire signal to v2 due to the second fire signal at time t2. Then, after the second report at time t2, the address No. As shown in FIG. 4C, the first address signal is transmitted as the transistor Q2 of the first fire detector 14 is turned on / off. Looking at the sensor line voltage shown in FIG. 4A, transmission of the address signal from time t3 causes the sensor line voltage to change pulse between v2 and v4 and transmits the first address signal. It will follow.

  In addition, the address No. at which the second fire was issued at time t2. 2, the transistor Q2 of the second switching circuit 40 is turned on / off at a time t4 after a certain time and when the first address is not transmitted, and the result is shown in FIG. As shown, the second address signal is transmitted. Looking at the sensor line voltage shown in FIG. 4A, transmission of the address signal from time t4 causes the sensor line voltage to change pulse between v2 and v4, and transmits the second address signal. It will follow.

  In addition, address No. n fire detector 14, as shown in FIG. At time t5 following the timing t4 when the second fire detector 14 transmits the address signal, a fire is detected and issued, and by turning on the transistor Q1 of the first switching circuit 38, the current I1 is supplied to the sensing line 12 as a fire signal. Shed.

  For this reason, the address No. n at the time t5 when the fire detector 14 issued the alarm, the address no. 1 and No. Since the fire detector 14 of No. 2 has fired the first and second fires, a current (3 × I1) that is the sum of the first to third reports as a fire signal is sent to the sensor line 12. Flowing. Corresponding to the third report, the sensor line voltage shown in FIG. 4A drops from v2 due to the second fire signal to v3 due to the third fire signal at time t5.

  In addition, the address No. that issued the third fire at time t5. In the n fire detectors 14, the transistor Q2 of the second switching circuit 40 is turned on / off at a time t6 after a predetermined time and when the addresses of the first and second reports are not transmitted. As shown in (G), the third address signal is transmitted. Looking at the sensor line voltage shown in FIG. 4A, transmission of the address signal from time t6 causes the sensor line voltage to change pulse between v3 and v5, and the third address signal is transmitted. It will follow.

  Such an address No. 1, no. 2, no. n in response to the first, second and third fire alarms of each of the fire detectors 14, the receiver 10 has an address No. at time t 1. A fire signal is displayed when the transistor Q1 of the fire detector 14 of the first fire sensor 14 is turned on, a fire representative display is performed, and a district display is performed based on which of the sensor lines 12-1 to 12-m the fire signal is received from. .

  Further, if necessary, the address No. at times t1, t2, and t5. 1, no. 2, no. The number of alarms is determined from the change in the voltage between the terminals of the sensor line 12 due to the first to third fire signals of the n fire detectors, thereby recognizing and displaying the second and subsequent reports. Even if there are four or more fire detectors 14 that have sent a fire signal, the number of alarms can be similarly determined from the change in the voltage across the terminals of the sensor line 12, and the fourth and subsequent reports can be recognized and displayed. Is possible.

  In order to determine the number of alarms from the change in the voltage across the terminals of the sensor line 12, for example, when the fire alarm system according to the present invention is installed, the fire alarms 14 are tested one by one. The voltage change data of the sensor line 12 at that time may be stored in the receiver 10, and the voltage change of the sensor line 12 may be compared with this data during operation of the fire alarm system.

  Even if the number of fire detectors 14 connected to each sensor line 12 is different or the length of each sensor line 12 is different, this voltage change data is stored and compared for each sensor line 12. That's fine.

  In addition, when the voltage is lowered due to the sum of the first and subsequent fire signals, the fire detector that has been triggered by receiving an address signal having a pulse change transmitted from the fire detector 14 14 can be identified, and necessary display or control of the address and district name of the fire detector 14 can be performed.

  Also, assuming that all the fire detectors 14 connected to the sensor line 12 have reported, if the maximum number of connections is 16, for example, 16 fire signals and 1 Even if the voltage between the terminals of the sensor line 12 is reduced to 6 V, for example, by the address signal, if the minimum operating voltage of the fire detector 14 is 6 V or less, the fire detector 14 continues to operate and transmits the address signal repeatedly. can do.

  In FIG. 4F, the address No. n fire detector 14 transmits a fire signal at time t5. 2 while the second fire detector 14 is transmitting the second address signal from time t4. When the n fire detectors 14 transmit a fire signal, the receiver 10 cannot normally receive the second address signal.

  Even if the receiver 10 fails to receive the address signal due to such a case or other factors, if the fire detector 14 repeatedly transmits the address signal, the same address signal can be received again, and the fire that has been triggered Identification of the sensor 14 is ensured.

  5 is a time chart when the transmission of the address signal in FIG. 3 is repeated. As in FIG. After the fire detector 14 of No. 1 performs the first fire alarm, the address No. 2 fire detector 14 issues the second fire, and address No. In this example, n fire detectors 14 perform the third fire alarm.

  For this reason, the transmission of a fire signal by the first, second, and third fires at times t1, t2, and t5, the subsequent first address signal, the second address signal, The transmission of the address signal for the bulletin is the same as in the time chart of FIG.

  Thereafter, the address No. 1, no. 2, no. The n fire detectors 14 repeat transmission of the first to third address signals at regular time intervals in a state where the detector line voltage has decreased by vd from the normal monitoring time.

  In the time charts of FIGS. 4 and 5, depending on the timing of the first fire detection and the second fire detection, if the address signal is transmitted after a certain time has elapsed since the fire signal was transmitted, There is a risk of being indistinguishable due to timing overlap.

  In order to prevent this, the signal state of the sensor line 12 is read before transmitting the address signal, and it is confirmed that no address signal is transmitted from another fire sensor 14 and the address signal is transmitted. To do.

  In addition, after receiving the timing signal from the receiver 10, the address may be transmitted in order from the first report, or may be transmitted sequentially based on a predetermined transmission time timing in the order of notification. good.

  FIG. 6 is a flowchart showing the alarm control process by the fire detector 14 of FIG. In FIG. 6, when a fire alarm is determined in step S <b> 1, the process proceeds to step S <b> 2 and a fire signal is transmitted by turning on / off the transistor Q <b> 1 of the first switching circuit 38.

  Next, when it is confirmed in step S3 that there is no address signal generated by another fire detector on the sensor line after a predetermined time, the process proceeds to step S4, and the address is determined by turning on / off the transistor Q2 of the second switching circuit 40. Send a signal.

  If there is an address signal sent from another fire detector on the sensor line in step S3, repeat the process of step S3 and confirm that there is no address signal on the line after a certain period of time. Thus, the address signal is transmitted in step S4.

  Until the fire recovery is confirmed in step S5, the address signal transmission in steps S3 and S4 is repeated. If fire recovery is determined in step S5, the process proceeds to step S6, where initialization processing is performed, and then the process returns to step S1.

  FIG. 7 is a flowchart showing reception control processing by the receiver 10 of FIG. In FIG. 7, the counter is initialized in step S11, the signal states received by the receiving circuit unit 20 are sequentially read for each sensor line 12 in step S12, and whether or not a fire signal is received is checked in step S13. The processing of step S12 returns to the first sensor line 12 after reading the signal states of all the sensor lines 12, and repeats the same process.

  If it is determined in step S13 that a fire signal has been received, the process proceeds to step S14, where fire alarm processing such as representative fire display and district display corresponding to the alarm line is performed. If no fire signal is received, steps S12 to S13 are performed. Repeat the process.

  Next, reception of an address signal is checked in step S15, and when an unreceived address signal whose address is not identified at that time is received, the counter is incremented by 1 in step S16. In step S17, necessary display such as the address of the fire sensor 14 identified first is performed. When n = 2, necessary display of the address of the fire sensor 14 identified second is performed.

  Thereafter, the processes in steps S14 to S17 are repeated, and if the address signal cannot be received in step S15, the elapsed time since the last fire signal was received is checked in step S18, and step S15 is performed until a predetermined time elapses. , S18 is repeated.

  If the predetermined time has elapsed in step S18, the process proceeds to step S19. In step S19, the number N of fire signals received is determined based on the voltage drop amount of the sensor line 12, and the address signal received in step S20. And the number N of fire signals received are compared.

  If n and N match in step S20, the presence / absence of fire recovery is checked in step S21. If they do not match, a failure report process for displaying an address reception failure warning is performed in step S22 before proceeding to step S21.

  If the fire is not restored in step S21, the process returns to the fire alarm process in step S14, and the processes in steps S14 to S21 are repeated until the fire is restored in step S21. If fire recovery can be confirmed in step S21, initialization processing is performed in step S23, and the process returns to step S11.

The present invention includes appropriate modifications that do not impair the object and advantages thereof, and is not limited by the numerical values shown in the above embodiments.

10: Receivers 12-1 to 12-m: Sensor line 14: Fire sensor 16: Terminating resistor 18: MPU
20-1 to 20-m: reception circuit unit 22: operation unit 24: alarm display unit 26: district display unit 28: message output unit 30: memory 32: reception control unit 34: rectifier circuit / noise absorption circuit 36: switching Circuit 38: first switching circuit 40: second switching circuit 42: constant voltage / current limiting circuit 44: operation indicator lamp 46: address setting circuit 48: alarm control unit 50: oscillation circuit 52: light emitting element 54: light receiving element 56 : Amplifier circuit 58: Comparison circuit

Claims (6)

In a fire alarm system comprising a receiver for notifying a fire based on a voltage change between sensor line terminals due to a change in current flowing in a sensor line connected to a plurality of fire detectors,
When the fire detector detects and fires, it generates a first voltage change between the sensor line terminals, so that a fire signal common to the plurality of fire detectors is sent to the receiver. An alarm control unit for transmitting and subsequently generating a second voltage change between the sensor line terminals and transmitting different address signals to the receiver for each of the plurality of fire detectors;
The receiver
The fire signal and the address signal are received, and the number of fire alarms to be reported is determined from the first voltage change in a time zone in which the address signal is not received after the fire signal is received, and the determination Compare the number of fire detectors reported and the number of fire detectors identified by the received address signal. If they match, a fire alarm is output and the fire detector identification information And a reception control unit that outputs a reception failure report of the address signal when they do not match,
A display unit capable of displaying the fire alarm, identification information and reception failure report;
With
The first voltage change is a steady change that is a predetermined voltage drop with respect to the voltage between the terminals of the sensor line in a normal state,
The second voltage drop is a pulse change based on the address signal from the notification control unit,
The alarm control unit transmits the address signal to the receiver in a time zone in which the second voltage change does not occur between the sensor line terminals after transmitting the fire signal. Fire alarm system.
2. The fire alarm system according to claim 1, wherein the first voltage change and the second voltage change when all the fire detectors connected to the sensor line transmit the fire signal. The fire alarm system characterized in that the applied total voltage change is smaller than the voltage across the terminals of the sensor line during normal operation.
3. The fire alarm system according to claim 2, wherein a voltage between the terminals of the sensor line when the total voltage changes is higher than a minimum operating voltage of the fire sensor.
2. The fire alarm system according to claim 1, wherein the alarm controller repeatedly transmits the address signal.
2. The fire alarm system according to claim 1, wherein the reception control unit outputs a fire alarm together with the reception fault information when the number of alarms of the fire detectors does not match. .
  6. The fire alarm system according to claim 1 or 5, wherein the reception control unit identifies the number of fire detectors to be notified by an address signal received within a predetermined time after receiving the last fire signal. A characteristic fire alarm system.

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