JP2020021263A - Master unit, automatic fire alarm system, control method, and program - Google Patents

Abstract

To provide an automatic fire alarm system capable of constituting a system that is unlikely to cause problems.SOLUTION: A master unit 1 is connected to a slave device 2 via a pair of electric wires 31, 32. The master unit 1 includes a communication part 13 and a mode switching part 171. The communication part 13 has a first communication function and a second communication function. The first communication function is a function of detecting a short circuit between the pair of electric wires 31 and 32 and receiving a fire report notifying the occurrence of a fire. The second communication function is a function of receiving an address for identifying the slave unit 2 by communicating with the slave unit 2 via the pair of electric wires 31 and 32. The mode switching part 171 switches the operation mode of the communication part 13 between a first mode in which a fire alarm is received from the slave unit 2 and a second mode in which the first communication function and the second communication function are valid.SELECTED DRAWING: Figure 1

Description

  The present disclosure generally relates to a master unit, an automatic fire alarm system, a control method, and a program, and more particularly, to a master unit that is a receiver of the automatic fire alarm system, an automatic fire alarm system including the master unit, and the master unit. And a program for controlling the same.

  Patent Literature 1 describes an example of a conventional automatic fire alarm system.

  The automatic fire alarm system described in Patent Literature 1 includes a slave unit and a master unit. The slave unit constitutes, for example, a heat sensor, a smoke sensor, a flame sensor, and the like. The master unit is a receiver to which a notification of a fire occurrence is issued from the slave unit. The slave unit and the master unit are connected to a pair of electric wires.

  When detecting the occurrence of the fire, the slave unit increases the current drawn from the pair of electric wires into the current drawer from the first level current value to the second level current value, and transmits an alarm signal. Also, at the time of alarm, the slave transmits an identification signal indicating a unique identifier to the master, so that the master can identify the alarm source for each slave. In the automatic fire alarm system, when no alarm is issued (normal time), communication between the master unit and the slave unit is performed, and an automatic test is performed on the communication status between the master unit and the slave unit and the operation of the slave unit. can do.

JP 2015-207125 A

  By the way, in the automatic fire alarm system described in the patent document, a pair of electric wires (hereinafter, referred to as “second specified handset”) different from the above-described handset (hereinafter, referred to as “first specified handset”) are connected to a pair of electric wires. Is connected, there is a possibility that transmission and reception of signals between the parent device and the first specific child device may be hindered by the second specific child device. For this reason, in the automatic fire alarm system of Patent Literature 1, when the second specific child device is connected to the pair of electric wires, communication failure between the parent device and the first specific child device easily occurs, and communication failure and the like occur. There was a possibility that troubles such as an increase in troubles would occur.

  The present disclosure has been made in view of the above circumstances, and an object of the present disclosure is to provide a master unit, an automatic fire alarm system, a control method, and a program capable of constructing an automatic fire alarm system in which a failure hardly occurs. .

  The master unit according to an aspect of the present disclosure is connected to the slave unit via a pair of electric wires. The master unit includes a communication unit and a mode switching unit. The communication unit has a first communication function and a second communication function. The first communication function is a function of receiving a fire report notifying the occurrence of a fire by detecting a short circuit between the pair of electric wires. The second communication function is a function of receiving an address for identifying the slave unit by communicating with the slave unit via the pair of electric wires. The mode switching unit switches an operation mode of the communication unit between a first mode in which the fire report is received from the child device and a second mode in which the first communication function and the second communication function are valid. .

  An automatic fire alarm system according to an aspect of the present disclosure includes the master unit and the slave unit.

  A control method according to an aspect of the present disclosure is a control method of a master unit connected to a slave unit via a pair of electric wires. The master unit includes a communication unit having a first communication function and a second communication function. The first communication function is a function of receiving a fire report notifying the occurrence of a fire by detecting a short circuit between the pair of electric wires. The second communication function is a function of receiving an address for identifying the slave unit by communicating with the slave unit via the pair of electric wires. The control method includes switching an operation mode of the communication unit between a first mode in which the fire report is received from the slave unit and a second mode in which the first communication function and the second communication function are valid. including.

  A program according to an embodiment of the present disclosure causes a computer system to execute the control method.

  According to the present disclosure, it is possible to construct an automatic fire alarm system that does not easily cause a problem.

FIG. 1 is a block diagram illustrating a schematic configuration of an automatic fire alarm system including a master device according to an embodiment of the present disclosure. FIG. 2 is a block diagram showing the overall configuration of the automatic fire alarm system according to the first embodiment. FIG. 3 is an explanatory diagram for explaining an operation state of the automatic fire alarm system including the master unit of Comparative Example 1. FIG. 4 is an explanatory diagram for explaining an operation state of the automatic fire alarm system including the master unit of Comparative Example 2. FIG. 5 is an explanatory diagram for explaining an operation state of the automatic fire alarm system including the master unit of the embodiment. FIG. 6 is a block diagram showing a schematic configuration of a master device according to a modification of the above embodiment.

(1) Embodiment (1.1) Outline Hereinafter, a master device 1 of the present embodiment and an automatic fire alarm system 100 including the same will be described with reference to the drawings.

  As shown in FIG. 1, the master device 1 of the present embodiment includes an application unit 11 that applies a voltage between a pair of electric wires 31 and 32.

  As shown in FIG. 2, the automatic fire alarm system 100 according to the present embodiment includes a plurality of slave units 2 in addition to the master unit 1. Each of the plurality of slaves 2 is one of the first slave 21 and the second slave 22. Each slave 2 is electrically connected to the master 1 via a pair of electric wires 31 and 32.

  The first handset 21 has a notification function. The notification function is a function of switching the pair of electric wires 31 and 32 from a state in which they are not short-circuited to a state in which they are short-circuited. When detecting the occurrence of a fire, the first slave unit 21 transmits a signal for notifying the occurrence of a fire (hereinafter, referred to as “fire report”) to the base unit 1 by the notification function. That is, the first slave unit 21 here is a contact-type fire detector used in a so-called P-type (Proprietary-type) automatic fire alarm system.

  The second handset 22 has the same notification function as the first handset 21. That is, when detecting the occurrence of a fire, the second slave unit 22 transmits a fire report to the master unit 1 by the notification function.

  The second slave unit 22 has a slave side communication function in addition to the notification function. The slave unit-side communication function is a function of performing bidirectional communication with the master unit 1 using a transmission signal transmitted through the pair of electric wires 31 and 32. When the second slave unit 22 receives a transmission signal including an address request for requesting an address (identifier) of a fire alarm issuance source from the master unit 1 at the time of alerting (when transmitting a fire alert), The pre-assigned address is transmitted to the base unit 1 using the side communication function.

  Master device 1 includes communication unit 13 and mode switching unit 171.

  The communication unit 13 has a first communication function (fire report receiving function) and a second communication function. The first communication function is a function of receiving a fire report from the child device 2 by detecting a short circuit between the pair of electric wires 31 and 32. The second communication function receives an address for identifying the child device 2 (the second child device 22) by communicating with the child device 2 (the second child device 22) via the pair of electric wires 31 and 32. Function. More specifically, the second communication function is to perform bidirectional communication with the slave unit 2 (second slave unit 22) using a transmission signal transmitted through the pair of electric wires 31 and 32, so that the slave unit 2 ( This is a function for receiving an address for identifying the second slave unit 22).

  The mode switching unit 171 switches the operation mode of the communication unit 13 between the first mode and the second mode.

  The first mode is an operation mode of the communication unit 13 for receiving a fire report from the slave unit 2. Here, the first mode is an operation mode of the communication unit 13 in which the first communication function is valid and the second communication function is invalid. That is, in the first mode, the mode switching unit 171 enables the first communication function and disables the second communication function. Therefore, in the first mode, the communication unit 13 detects a short circuit between the pair of electric wires 31 and 32 using the first communication function, and thereby causes the child device 2 (the first child device 21 and the second child device 22) Fire information is received. Further, in the first mode, the communication unit 13 does not transmit / receive a transmission signal to / from the slave unit 2 (the second slave unit 22), and performs communication with the slave unit 2 (the second slave unit 22). To stop.

  The second mode is an operation mode of the communication unit 13 in which the first communication function and the second communication function are valid. That is, the mode switching unit 171 enables the first communication function and the second communication function in the second mode. Therefore, in the second mode, the communication unit 13 receives a fire report from the slave unit 2 by detecting a short circuit between the pair of electric wires 31 and 32 using the first communication function. In the second mode, the communication unit 13 transmits and receives a transmission signal to and from the slave unit 2 (second slave unit 22) by using the second communication function, and the slave unit 2 (second slave unit). Device 22) is received.

  As described above, the master unit 1 of the automatic fire alarm system 100 according to the present embodiment can switch the operation mode of the communication unit 13 between the first mode and the second mode.

  For example, when only the second slave unit 22 is connected to the pair of electric wires 31 and 32, the mode switching unit 171 sets the operation mode of the communication unit 13 to the second mode. As a result, the base unit 1 can receive a fire report from the slave unit 2 (second slave unit 22) by the first communication function, and the slave unit 2 (second slave unit) by the second communication function. The address can be received from the slave unit 2 by the two-way communication with the slave unit 22). Therefore, when the slave unit 2 (the second slave unit 22) issues an alert, the master unit 1 receives an address from the slave unit 2 that is the alarm source, so that the slave unit 2 (the second slave unit 22) is united. The source of the alert can be specified.

  For example, when at least one first slave unit 21 is connected to the pair of electric wires 31 and 32, the mode switching unit 171 sets the operation mode of the communication unit 13 to the first mode. Thereby, the base unit 1 can receive a fire report from the slave unit 2 (the first slave unit 21 and the second slave unit 22) by the first communication function. Further, in the first mode, by disabling the second communication function, communication between the parent device 1 and the child device 2 (the second child device 22) is stopped. For this reason, occurrence of troubles such as communication failure between the parent device and the second child device 22 is suppressed, and the occurrence of problems can be reduced.

  Note that the switching between the first mode and the second mode by the mode switching unit 171 does not necessarily have to be realized by switching the second communication function between invalid and valid. The base unit 1 only needs to be able to receive a fire report from the slave unit 2 in the first mode. For example, the first mode of the communication unit 13 is a mode for receiving a fire report by a function other than the first communication function. You may.

(1.2) Overall Configuration As shown in FIG. 2, an example in which the automatic fire alarm system 100 of the present embodiment is used for an apartment house A1 (for example, an apartment) will be described. Of course, the automatic fire alarm system 100 of the present embodiment is not limited to the apartment house A1, and may be used in various buildings such as commercial facilities, hospitals, hotels, multi-story buildings, and the like.

  As shown in FIG. 2, the automatic fire alarm system 100 according to the present embodiment is provided with one master unit 1 and a plurality of slave units 2 for one apartment house A1. In the automatic fire alarm system 100, a plurality of (four in this case) communication lines L1 are connected to the master unit 1 with the pair of electric wires 31, 32 as one communication line L1. Two or more (here, four) slave units 2 are connected to each communication line L1.

  All of the two or more slaves 2 connected to each communication line L1 may be the first slave 21, all of the slaves 22 may be the second slave 22, or the first slave 22. The child device 21 and the second child device 22 may be mixed. In the illustrated example, a plurality of (four) second slave units 22 are connected to the first communication line L11 of the four communication lines L1. In addition, at least one first slave unit 21 and at least one second slave unit 22 are connected to the second communication line L12 and the second communication line L13 of the four communication lines L1. Further, to the fourth communication line L14 of the four communication lines L1, only a plurality of (four) first slave units 21 are connected.

  In the automatic fire alarm system 100, a maximum of 60 slave units 2 (the first slave unit 21 or the second slave unit 22) can be connected to each communication line L1. Further, a single master unit 1 can be connected to a maximum of 120 communication lines L1. Accordingly, up to 7200 (= 60 × 120) slave units 2 (first slave unit 21 or second slave unit 22) can be connected to one master unit 1. However, these numerical values are examples, and are not intended to limit the numerical values.

  Further, at the end of each communication line L1 (the end opposite to the master unit 1), the pair of electric wires 31, 32 is electrically connected via a terminating resistor C1. Therefore, master device 1 can detect a break in paired electric wires 31 and 32 by monitoring the current flowing between paired electric wires 31 and 32.

  The automatic fire alarm system 100 basically generates a fire in a slave unit 2 (first slave unit 21 and second slave unit 22) including a heat sensor, a smoke sensor, a flame sensor, and the like. Upon detection, the slave unit 2 is configured to notify a fire occurrence to the master unit 1 as a receiver. However, handset 2 is not limited to a detector that detects the occurrence of a fire, and may include a transmitter and the like. The transmitter has a push button switch (not shown), and when a person finds a fire, manually operates (pushes) the push button switch to notify the base unit 1 of a fire occurrence. is there.

  In addition, the automatic fire alarm system 100 may have a function of interlocking with other equipment such as smoke prevention equipment (not shown) and emergency broadcast equipment (not shown). In this case, when a fire occurs, the automatic fire notification system 100 can control the fire door of the smoke prevention equipment, or can notify the occurrence of the fire by sound or voice in the emergency broadcast equipment. .

  By the way, there are two types of general automatic fire alarm systems, P-type (Proprietary-type) and R-type (Record-type). The P-type automatic fire alarm system notifies a base unit of a fire by causing a slave unit to electrically short-circuit a pair of electric wires. In an R-type automatic fire system, a slave unit notifies a master unit of a fire by communication using a transmission signal transmitted through a transmission line.

  The automatic fire alarm system 100 of the present embodiment is based on a P-type. More specifically, in the present embodiment, in the apartment house A1 in which the P-type automatic fire alarm system has been installed, the existing wiring (communication line L1) is used as it is, and the existing master unit is used as the master unit 1. It is assumed that replacement is performed, and some of the existing plurality of slaves 2 (first slaves 21) are replaced with second slaves 22. Of course, the automatic fire alarm system 100 of the present embodiment can also be adopted as a newly introduced automatic fire alarm system.

  Hereinafter, the configurations of the parent device 1 and the child device 2 will be described in detail.

(1.3) Configuration of Master Unit In the present embodiment, master unit 1 is a P-type receiver that receives a fire notification from slave unit 2 (first slave unit 21 and second slave unit 22). . The master unit 1 is installed in, for example, a management room of a building (a housing complex A1).

  As shown in FIG. 1, in addition to the application unit 11 and the communication unit 13, the master unit 1 includes a resistor 12, a display unit 15 that performs various displays, an operation unit 16 that receives an operation input from a user, And a control unit 17 for controlling the Further, the communication unit 13 includes an identification unit 130, a reception unit 131, and a transmission unit 132.

  Master device 1 includes a plurality of application units 11 and a plurality of resistors 12 corresponding to a plurality of communication lines L1 (see FIG. 2). The communication unit 13 includes a plurality of identification units 130, a plurality of reception units 131, and a plurality of transmission units 132, each corresponding to a plurality of communication lines L1. However, for convenience of description, FIG. 1 shows only one communication line L1 and a configuration corresponding to the communication line L1, and the description will be made focusing on this communication line L1.

  The application unit 11 applies a predetermined voltage to the pair of electric wires 31 and 32 under the control of the control unit 17. Here, as an example, the voltage applied between the pair of electric wires 31 and 32 by the application unit 11 is DC 24 V, but is not limited to this value.

  The resistor 12 is connected between the application unit 11 and at least one of the pair of electric wires 31 and 32. In the example of FIG. 1, the resistor 12 is inserted between one of the pair of electric wires 31 and 32 (on the high potential side) and the application unit 11. However, without being limited to this example, the resistor 12 may be inserted between the other (low-potential side) electric wire 32 and the application unit 11, or both the pair of electric wires 31 and 32 and the application unit 11 may be inserted. May be inserted between them.

  The resistor 12 has a first function of converting a current flowing through the resistor 12 into a potential difference (voltage) between both ends of the resistor 12 by a voltage drop, and a pair of wires 31 and 32 when the pair of wires 31 and 32 are short-circuited. And a second function of restricting a current flowing through the power supply. In short, the resistor 12 has both the first function as a current-voltage conversion element and the second function as a current limiting element. Here, as an example, the resistance value of the resistor 12 is set to 470Ω, but is not limited to this value.

  The identification unit 130 is electrically connected between the application unit 11 and the pair of electric wires 31 and 32. The identification unit 130 determines a state in which the pair of wires 31 and 32 are short-circuited by the slave unit 2 (hereinafter, referred to as a “short-circuit state”) and a state in which the pair is not short-circuited (hereinafter, referred to as a “non-short-circuit state”). Identify. The identification unit 130 monitors the magnitude of the current flowing between the pair of electric wires 31 and 32, and distinguishes between the short-circuit state and the non-short-circuit state depending on whether the current exceeds a predetermined threshold. That is, the identification unit 130 determines that the current flowing between the pair of wires 31 and 32 is equal to or less than the threshold value, and determines that the current is not short-circuited. to decide.

  The communication unit 13 receives the fire alarm from the slave unit 2 by detecting the switching from the non-short state to the short state by the identification unit 130. That is, in the present embodiment, the first communication function (fire report receiving function) of the communication unit 13 is realized by the identification unit 130.

  The receiving section 131 is electrically connected between the resistor 12 and the pair of electric wires 31 and 32. The receiving unit 131 receives a current signal transmitted from the second slave unit 22 by drawing current from the pair of electric wires 31 and 32 as a voltage change between the pair of electric wires 31 and 32. That is, the current value of the current drawn by the second slave unit 22 from the pair of electric wires 31 and 32 corresponds to the magnitude of the voltage drop at the resistor 12. Therefore, the receiving unit 131 receives, as a transmission signal, a voltage change (voltage signal) generated on the pair of wires 31 and 32 when the second slave unit 22 changes the current drawn from the pair of wires 31 and 32. I do.

  The transmitting section 132 is electrically connected between the resistor 12 and the pair of electric wires 31 and 32. The transmitting unit 132 transmits the transmission signal to the second slave unit 22 by changing the current flowing from the pair of electric wires 31 and 32. That is, the transmitting unit 132 transmits the transmission signal to the second slave unit 22 by changing the current flowing through the pair of wires 31 and 32 by drawing the current flowing from the application unit 11 to the resistor 12.

  Thus, the communication unit 13 communicates with the second slave unit 22 via the pair of electric wires 31 and 32 by the reception unit 131 and the transmission unit 132. That is, in the present embodiment, the receiving unit 131 and the transmitting unit 132 implement the second communication function of the communication unit 13.

  The display unit 15 includes, for example, an LED (Light Emitting Diode), a liquid crystal display, an organic electroluminescence display, or the like. The display unit 15 displays, for example, the occurrence of a fire and the floor where the fire occurred (floor). When the display unit 15 obtains an address from the second slave unit 22 that has detected a fire, the display unit 15 displays the installation location of the second slave unit 22 associated with the address, thereby providing a notification source. It is also possible to display the installation location of the second slave unit 22.

  The operation unit 16 receives an input operation for performing various settings and the like of the automatic fire alarm system 100. The operation unit 16 includes a dip switch, a push button switch, and the like for receiving an input operation of a user (operator).

  The control unit 17 controls the identification unit 130, the reception unit 131, and the transmission unit 132 to cause the identification unit 130 to determine whether the pair of electric wires 31 and 32 is short-circuited or to transmit a signal from the transmission unit 132. Or the signal from the second slave unit 22 is received by the receiving unit 131. The control unit 17 has, for example, a main configuration including a computer having a CPU (Central Processing Unit) and a memory, and realizes various functions by executing a program stored in the memory by the CPU. The program may be recorded in a memory of a computer in advance, may be provided by being recorded in a recording medium such as a memory card, or may be provided through an electric communication line such as the Internet.

  The control unit 17 of the present embodiment includes a mode switching unit 171. The mode switching unit 171 switches the operation mode of the communication unit 13. Here, the mode switching unit 171 switches the operation mode (on / off) of the reception unit 131 and the transmission unit 132 to switch the operation mode of the communication unit 13 between the first mode and the second mode. The mode switching unit 171 switches the operation mode of the communication unit 13 to the first mode by stopping (turning off) the operations of the reception unit 131 and the transmission unit 132 and disabling the second communication function. The mode switching unit 171 switches the operation mode of the communication unit 13 to the second mode by operating (turning on) the reception unit 131 and the transmission unit 132 to enable the second communication function.

  In the base unit 1 of the present embodiment, the switching of the operation mode of the communication unit 13 by the mode switching unit 171 is performed according to an operation signal according to a user operation. Specifically, the mode switching unit 171 switches the operation mode of the communication unit 13 according to an operation performed on the operation unit 16 by the user. The operation unit 16 transmits an operation signal corresponding to a user operation (input operation) to the control unit 17 (mode switching unit 171), and the mode switching unit 171 transmits the operation signal of the communication unit 13 according to the operation signal from the operation unit 16. Switch the operation mode.

  The operation unit 16 has, for example, a plurality of (four) switches respectively corresponding to the plurality (four) of the communication lines L1. Then, the mode switching unit 171 switches the operation mode of the communication unit 13 for the communication line L1 associated with the operated switch according to the operation of the user on each switch. For example, when the switch corresponding to the communication line L11 is operated, the mode switching unit 171 switches the operation state (ON / OFF) of the receiving unit 131 and the transmitting unit 132 connected to the communication line L11. That is, the mode switching unit 171 is configured to switch the operation mode of the communication unit 13 for each communication line L1.

  In addition, base unit 1 further includes a backup power supply 18 using a storage battery so that a power supply for operating automatic fire alarm system 100 can be secured even in the event of a power failure. Base unit 1 uses a commercial power supply, a private power generation facility, or the like as a main power supply. The application unit 11 automatically switches the power supply source from the main power supply to the standby power supply 18 when the main power supply fails, and automatically switches from the standby power supply 18 to the main power supply when the main power supply is restored.

(1.4) Configuration of Child Unit Next, the configuration of the child unit 2 (the first child unit 21 and the second child unit 22) will be described with reference to FIG. In FIG. 1, a first slave unit 21 and a second slave unit 22 each composed of a sensor connected to one communication line L1 are illustrated one by one, and the other slave units 2 are not illustrated. .

  As shown in FIG. 1, the first slave unit 21 includes a (first) diode bridge 211, a (first) power supply unit 212, a (first) sensor 213, a thyristor 214, and a driving unit. 215.

  In the diode bridge 211, a pair of electric wires 31, 32 is electrically connected to an input terminal, and a power supply unit 212 and a thyristor 214 are electrically connected to an output terminal. The power supply unit 212 generates power for operating the first slave unit 21 by being supplied with power from the pair of electric wires 31 and 32. The sensor 213 detects the occurrence of a fire by detecting, for example, a change in the concentration of smoke, a change in temperature, and a change in the concentration of gas such as carbon monoxide. The drive unit 215 switches from the non-short circuit state to the short circuit state by turning on the thyristor 214 according to the output of the sensor 213.

  With this configuration, when detecting the occurrence of a fire, the first slave unit 21 turns on the thyristor 214 to bring the pair of electric wires 31 and 32 into a short-circuit state in which the pair is electrically short-circuited. Notify the user of a fire report (notification function).

  As shown in FIG. 1, the second handset 22 includes a (second) diode bridge 221, a (second) power supply unit 222, a (second) sensor 223, a transmission unit 224, The storage unit 225 includes a unit 225, a control unit 226, and a storage unit 227.

  In the diode bridge 221, a pair of electric wires 31 and 32 are electrically connected to an input end, and a power supply unit 222, a transmission unit 224, and a reception unit 225 are electrically connected to an output end. The power supply unit 222 generates power for operating the second slave unit 22 by being supplied with power from the pair of electric wires 31 and 32. The sensor 223 detects a fire by detecting, for example, a change in smoke concentration, a change in temperature, and a change in gas concentration such as carbon monoxide. The control unit 226 controls the transmission unit 224 and the reception unit 225 to transmit a fire report and a transmission signal from the transmission unit 224 to the base unit 1 or transmit a transmission signal from the base unit 1 in accordance with the output of the sensor 223. Is received by the receiving unit 225.

  The transmitting unit 224 transmits a signal to the base unit 1 by changing a current flowing through the pair of electric wires 31 and 32. That is, transmitting section 224 transmits a current signal to master device 1 by drawing and changing current from the pair of electric wires 31 and 32.

  In addition, the transmission unit 224 transmits a fire report by connecting an impedance element of an appropriate size between the pair of electric wires 31 and 32 and short-circuiting the pair of electric wires 31 and 32 (notification function). . That is, the transmitting unit 224 transmits a predetermined impedance element to the pair of electric wires 31 and 32 such that a current having a magnitude enough for the identification unit 130 to determine that the state has been switched from the non-short-circuit state to the short-circuit state flows through the pair of electric wires 31 and 32. , 32. Further, the transmission unit 224 transmits a current signal to the master unit 1 by increasing or decreasing the current value of the current drawn from the pair of wires 31 and 32 in a state where the pair of wires 31 and 32 are short-circuited in a simulated manner. It is possible.

  That is, the transmission unit 224 transmits a fire report by increasing the current drawn from the pair of electric wires 31 and 32 from the first level current value to the second level current value. In addition, the transmitting unit 224 increases the current drawn from the pair of electric wires 31 and 32 to the second level current value, and outputs the third level current value larger than the second level current value and the second level current value. The current signal is transmitted to the base unit 1 by increasing or decreasing the current value.

  Receiving section 225 receives the transmission signal from base unit 1 as a voltage signal (voltage change) on a pair of electric wires 31 and 32. That is, the current value of the current drawn by master device 1 from pair of electric wires 31 and 32 corresponds to the magnitude of the voltage drop at resistor 12. Therefore, receiving section 225 receives, as a voltage signal, a signal represented by the current value of the current drawn by base unit 1.

  As described above, the second slave unit 22 communicates with the master unit 1 via the pair of electric wires 31 and 32 by the transmission unit 224 and the reception unit 225. That is, in the present embodiment, the transmitting unit 224 and the receiving unit 225 implement the slave-side communication function of the second slave 22.

  The storage unit 227 stores an address (identifier) assigned to the second slave unit 22 in advance. A unique address is assigned to each of the plurality of second slave units 22. Each address is registered in the base unit 1 in association with the installation location (for example, room number) of each of the plurality of second slave units 22.

  With the above configuration, when detecting the occurrence of a fire, the second slave unit 22 first transmits a fire report by causing the transmission unit 224 to simulate a short circuit between the pair of electric wires 31 and 32. When the second slave unit 22 receives an address request for requesting the address of the fire report source from the master unit 1, the second slave unit 22 keeps the pair of wires 31 and 32 short-circuited in a pseudo manner, and , 32, the address is transmitted to the base unit 1.

  The second slave unit 22 communicates between the master unit 1 and the second slave unit 22 using a transmission signal during non-reporting (normal time), so that the master unit 1 and the second slave unit 22 communicate. An automatic test can be performed on the communication status between the devices 22 and the operation of the second child device 22 and the like.

(1.5) Advantages Next, advantages of the master unit 1 of the automatic fire alarm system 100 of the present embodiment will be described with comparison with Comparative Examples 1 and 2.

  The base unit 201 of the first comparative example is different from the base unit 1 of the embodiment mainly in that the communication unit does not have a configuration corresponding to the reception unit 131 and the transmission unit 132 described in the embodiment. That is, in the master unit 201 of Comparative Example 1, the communication unit has the first communication function, but does not have the second communication function. Therefore, in master device 201 of Comparative Example 1, the communication unit cannot operate in the second mode, and always operates in the first mode. Further, in master device 201 of Comparative Example 1, the control unit does not include a configuration corresponding to mode switching unit 171 described in the embodiment.

  As shown in FIG. 3, it is assumed that a first slave unit 21 and a second slave unit 22 are connected to a master unit 201 of Comparative Example 1 and an automatic fire alarm system 200 is constructed. In the example of FIG. 3, four second slaves 22 are connected to the first communication line L11. Two first slaves 21 and two second slaves 22 are connected to the second communication line L12. Three first slaves 21 and one second slave 22 are connected to the third communication line L13. Four first slaves 21 are connected to the fourth communication line L14.

  In this example, the master unit 201 uses the first communication function (fire report receiving function) for each of the first communication line L11 to the fourth communication line L14. 22 can receive a fire report. On the other hand, since master device 201 does not have the second communication function, communication between master device 201 and slave device 2 is not performed, and master device 201 cannot receive an address from slave device 2. In FIG. 3, the symbol “○” described adjacent to the communication lines L11 to L14 indicates that the master unit can receive the fire report from the slave unit but cannot receive the address. I have.

  Next, the master unit 301 of Comparative Example 2 has basically the same configuration as the master unit 1 of the first embodiment, but the control unit corresponds to the mode switching unit 171 described in the embodiment. Is different from the master unit 1 of the embodiment in that the master unit 1 is not provided. That is, in the parent device 301 of Comparative Example 2, the communication unit has both the first communication function and the second communication function, and always operates in the second mode.

  As for the parent device 301 of Comparative Example 2, similarly to the case of Comparative Example 1, the first child device 21 and the second child device 22 are connected to the parent device 301, and the automatic fire alarm system 300 is constructed. Assume that there is. As shown in FIG. 4, the type and number of the slaves 2 connected to each communication line L1 are the same as in the case of Comparative Example 1.

  In this example, for the first communication line L11, the master unit 301 can receive a fire report from the slave unit 2 (second slave unit 22) connected to the communication line L1 by the first communication function. In addition, an address can be received from the slave unit 2 (second slave unit 22) by the second communication function. In FIG. 4, the symbol “◎” written adjacent to the communication line L11 indicates that the parent device can receive a fire report and an address from the child device.

  On the other hand, in the second communication line L12 and the third communication line L13, the first slave unit 21 and the second slave unit 22 are connected to the communication line L1 in a mixed manner. In this case, even if the master unit 1 sends a transmission signal to the communication line L1 by the second communication function, the second slave unit 21 may lose its waveform due to, for example, a waveform of the transmission signal becoming dull due to the internal impedance of the first slave unit 21. Transmission of the transmission signal to the device 22 may be obstructed. Similarly, transmission of a transmission signal transmitted from the second slave unit 22 to the communication line L1 may be inhibited by the first slave unit 21. For this reason, in the second communication line L12, for example, when the master unit 1 and the second slave unit 22 communicate with each other by transmitting and receiving a signal a plurality of times in two directions, transmission of any signal is hindered. If this happens, a trouble such as a communication failure may occur. In FIG. 4, a symbol “△” described adjacent to the communication lines L12 and L13 indicates that a trouble such as communication failure may occur between the master unit and the slave unit. I have.

  In the fourth communication line L14, only the first slave unit 21 is connected to the communication line L1. In this case, since the first handset 21 does not have the handset side communication function, communication between the base unit 1 and the handset 2 is not performed, and the base unit 201 receives the address from the handset 2. Can not. On the other hand, the base unit 1 can receive a fire report from the slave unit 2 (first slave unit 21) by the first communication function (fire report reception function).

  Next, also in the base unit 1 of the present embodiment, as in the case of the comparative example 1 and the comparative example 2, the first sub unit 21 and the second sub unit 22 are connected to the main unit 1, and the automatic fire is performed. It is assumed that the notification system 100 has been constructed. As shown in FIG. 5, the types and numbers of the slaves 2 connected to each communication line L1 are the same as those in the comparative examples 1 and 2.

  As described above, the base unit 1 of the present embodiment can switch the operation mode of the communication unit 13 between the first mode and the second mode.

  Therefore, for example, for the first communication line L11, by setting the operation mode of the communication unit 13 to the second mode, the slave unit 2 is set in the same manner as in the case of the first communication line L11 in the master unit 301 of Comparative Example 2. It is possible to receive a fire report and an address from the (second handset 22). On the other hand, with respect to the second to fourth communication lines L12 to L14, if the operation mode of the communication unit 13 is set to the first mode, it is possible to receive the fire report from the child device 2 and to connect the parent device 1 and the child device. It is possible to suppress the occurrence of troubles such as communication failure with the communication device 2.

  The base unit 1 according to the present embodiment includes a base unit 1 having a second communication function and a second slave unit in an apartment house A1 in which a P-type automatic fire alarm system is introduced, while using existing wiring as it is. This is particularly advantageous when introducing 22 (at the time of renewal). Note that the P-type automatic fire alarm system corresponds to an automatic fire alarm system including the master unit 201 and the plurality of first slave units 21 in the first comparative example. In the P-type automatic fire alarm system, the master unit 201 can receive a fire report from the slave unit 2 (first slave unit 21), but cannot receive an address, perform an automatic test, and the like.

  For example, suppose that in the apartment house A1 in which the P-type automatic fire alarm system is introduced, the master unit 201 is replaced with a master unit 301 as a master unit having the second communication function. When replacing the first slave unit 21 with the second slave unit 22 from this state, only a part of the plurality of first slave units 21 connected to one communication line L1 is replaced with the second slave unit. When the communication device is replaced with the communication device 22, the state becomes the same as the communication lines L12 and L13 in FIG. Therefore, a trouble such as a communication failure may occur on the communication line L1. Therefore, it is necessary to stop all communication (notification of fire alarm and transmission / reception of transmission signals) between master unit 301 and slave unit 2 until all first slave units 21 are replaced with second slave units 22. There is.

  On the other hand, in the apartment house A1 in which the P-type automatic fire alarm system is introduced, when the master unit 201 is replaced with the master unit 1 as the master unit having the second communication function, the above-described inconvenience is caused. Generation can be suppressed. That is, in the procedure for replacing the first slave unit 21 with the second slave unit 22, the communication unit 13 is operated in the first mode for the communication line L1 to which at least one first slave unit 21 is connected. Then, it is possible to receive at least the fire report from the slave unit 2. Then, after all the slaves 2 are replaced with the second slaves 22, if the operation mode of the communication unit 13 is switched to the second mode, the transmission signal between the slaves 2 (the second slave 22) is transmitted. Communication via the Internet becomes possible. That is, according to the master unit 1 of the present embodiment, it is not necessary to stop communication between the master unit and the slave unit 2 at the time of renewal, and when replacing the master unit of the P-type automatic fire alarm system. It is possible to eliminate the inconvenience that occurs.

  Of course, the automatic fire alarm system 100 of the present embodiment can be adopted as a newly introduced automatic fire alarm system. For example, of the plurality of communication lines L1, the communication unit 13 is operated in the first mode for the communication line L1 to which at least one first slave unit 21 is connected, and only the second slave unit 22 is connected. As for the communication line L1, the communication unit 13 is operated in the second mode.

(2) Modifications The embodiments described above are only one of various embodiments of the present disclosure. The above-described embodiment can be variously modified according to the design and the like as long as the object of the present disclosure can be achieved. Further, the same functions as those of the control unit 17 of the master device 1 may be embodied by a control method, a computer program, a non-temporary recording medium recording the computer program, or the like.

  The control method according to one aspect is a method of controlling master device 1 connected to slave device 2 via a pair of electric wires 31 and 32. Master device 1 includes communication unit 13. The communication unit 13 has a first communication function and a second communication function. The first communication function is a function of detecting a short circuit between the pair of electric wires 31 and 32 and receiving a fire report notifying the occurrence of a fire. The second communication function is a function of receiving an address identifying the slave 2 by communicating with the slave 2 via the pair of electric wires 31 and 32. This control method includes switching the operation mode of the communication unit 13 between a first mode in which a fire alarm is received from the slave unit 2 and a second mode in which the first communication function and the second communication function are valid.

  A program according to an aspect is a program that causes a computer system to execute the above control method.

  Hereinafter, modified examples of the above-described embodiment will be listed. The modifications described below can be applied in appropriate combinations.

  In the automatic fire alarm system 100 according to the present disclosure, the control unit 17 and the like of the master unit 1 include a computer system. The computer system mainly has a processor and a memory as hardware. When the processor executes the program recorded in the memory of the computer system, the function as the control unit 17 of the parent device 1 in the present disclosure is realized. The program may be pre-recorded in the memory of the computer system, may be provided through an electric communication line, or may be recorded in a non-transitory recording medium such as a memory card, an optical disk, or a hard disk drive readable by the computer system. May be provided. A processor of a computer system is composed of one or more electronic circuits including a semiconductor integrated circuit (IC) or a large-scale integrated circuit (LSI). An integrated circuit such as an IC or an LSI referred to here differs depending on the degree of integration, and includes an integrated circuit called a system LSI, a VLSI (Very Large Scale Integration), or a ULSI (Ultra Large Scale Integration). Furthermore, an FPGA (Field-Programmable Gate Array), which is programmed after the manufacture of the LSI, or a logic device capable of reconfiguring the connection relation inside the LSI or reconfiguring the circuit section inside the LSI, is also adopted as the processor. Can be. The plurality of electronic circuits may be integrated on one chip, or may be provided separately on a plurality of chips. The plurality of chips may be integrated in one device, or may be provided separately in a plurality of devices. The computer system includes a microcontroller having one or more processors and one or more memories. Therefore, the microcontroller is also composed of one or more electronic circuits including a semiconductor integrated circuit or a large-scale integrated circuit.

  The fact that a plurality of functions in the control unit 17 of the master unit 1 are integrated in one housing is not an essential configuration of the control unit 17. That is, the components of the control unit 17 may be provided separately in a plurality of housings. Further, at least a part of the function of the control unit 17 may be realized by a cloud (cloud computing) or the like.

  In the above-described embodiment, the mode switching unit 171 switches the operation mode of the communication unit 13 according to an operation performed on the operation unit 16 by the user, but is not limited thereto. For example, base unit 1 may further include a wireless communication unit, and mode switching unit 171 may switch the operation mode of communication unit 13 according to an operation signal received via the wireless communication unit. The wireless communication unit may receive, for example, an operation signal from a mobile terminal or the like owned by a user (operator) via a server or the like.

  Alternatively, the mode switching unit 171 automatically switches the operation mode of the communication unit 13 from the first mode to the second mode when a certain condition (first condition) is satisfied, not in response to the operation signal. Is also good. The first condition may be, for example, that all of the slaves 2 connected to the communication line L1 are determined to be the second slaves 22. Similarly, the mode switching unit 171 may automatically switch the operation mode of the communication unit 13 from the second mode to the first mode when a certain condition (second condition) is satisfied. The second condition may be, for example, that at least one of the slaves 2 connected to the communication line L1 is determined to be the first slave 21.

  In short, as shown in FIG. 6, the control unit 17 of the master unit 1 may further include a detection unit 172 for detecting a communication state with the slave unit 2 connected to the pair of electric wires 31, 32. . Then, the mode switching unit 171 may switch the operation mode of the communication unit 13 according to the communication status with the slave unit 2 detected by the detection unit 172.

  For example, the detecting unit 172 communicates with the child device 2 (by performing communication with the child device 2) via the pair of electric wires 31 and 32 (by communicating with the child device 2). The communication status may be detected.

  In one specific example, the operation unit 16 is configured to receive an operation input relating to the number of slaves 2 connected to each communication line L1 from a user. Master device 1 includes a number storage unit. The number storage unit stores the number of slave units 2 connected to each communication line L1 received by the operation unit 16. Then, the detection unit 172 causes the transmission unit 132 to periodically (eg, every 1 to 2 hours) transmit a transmission signal (reply request signal) including a reply request for requesting a reply to the communication line L1. The detecting unit 172 detects the number of the second slave units 22 connected to each communication line L1, based on the transmission signal (reply to the reply request signal) transmitted from the slave unit 2 and received by the receiving unit 131. . Here, the first handset 21 of the handset 2 does not have the handset side communication function, and therefore cannot receive the transmission signal including the reply request, and transmits the transmission signal to the base unit 1. You can't. On the other hand, when the second slave unit 22 receives the transmission signal including the reply request from the master unit 1, the second slave unit 22 can send a reply to the master unit 1 by the slave unit communication function. Thereby, the detection unit 172 can know the number of the second slave units 22 connected to each communication line L1. If the number of connected slave units 2 stored in the number storage unit matches the number of the second slave units 22 detected by the detection unit 172, the control unit 17 determines the number of slave units connected to the communication line L1. It is determined that all the devices 2 are the second child devices 22. In response to this determination, the mode switching unit 171 may switch the operation mode of the communication unit 13 from the first mode to the second mode. In short, the communication unit 13 (the transmission unit 132) sends a reply request signal to the pair of electric wires 31 and 32 and receives a reply from the handset 2 (the second handset 22) that has received the reply request signal. The detecting unit 172 determines the number of slaves 2 (second slaves 22) that have returned a reply to the reply request signal (more specifically, the number of slaves 22 connected to the pair of electric wires 31 and 32). The communication status with the handset 2 is detected based on the number and the number of the second handset 22 that has returned the reply request signal. The mode switching unit 171 switches the operation mode of the communication unit 13 from the first mode to the second mode according to the number of slaves 2 (second slaves 22) to which a reply has been made.

  Alternatively, even when the first slave unit 21 is connected to the communication line L1, the mode switching unit 171 can communicate with all the second slave units 22 connected to the communication line L1. If it can be determined, the operation mode of the communication unit 13 may be switched to the second mode. That is, the first condition may be that it is determined that communication is possible with all the second slave units 22 connected to the communication line L1. For example, the mode switching unit 171 may switch the operation mode of the communication unit 13 according to the transmission characteristics of each communication line L1. For example, if the detection unit 172 receives a reply from the second child device 22 farthest from the parent device 1 (the distance on the communication line L1) among the second child devices 22 connected to the communication line L1, Alternatively, it may be determined that communication with all the second slave units 22 connected to the communication line L1 is possible. The mode switching unit 171 may switch the operation mode of the communication unit 13 from the first mode to the second mode according to this determination. For example, the detecting unit 172 specifies the second slave unit 22 farthest from the master unit 1 (for example, by using an address), and causes the transmitting unit 132 to transmit a transmission signal including a reply request to the communication line L1. Then, if there is a reply from the second slave unit 22, the detection unit 172 may determine that communication with all the second slave units 22 connected to the communication line L1 is possible.

  In the above-described embodiment, the mode switching unit 171 switches the operation mode of the communication unit 13 for each communication line L1, but is not limited thereto. For example, the mode switching unit 171 may switch the operation mode of the communication unit 13 for all the communication lines L1 at once. Alternatively, the mode switching unit 171 may switch the operation mode of the communication unit 13 for each communication line group including at least one communication line L1 among the plurality of communication lines L1. For example, the mode switching unit 171 may be configured to collectively switch the operation mode of the communication unit 13 for the first communication line group including the first communication line L1 and the second communication line L2.

(3) Aspect As is clear from the above-described embodiments and modifications, the master unit (1) according to the first aspect is connected to the slave unit (2) via a pair of electric wires (31, 32). The parent device (1) includes a communication unit (13) and a mode switching unit (171). The communication unit (13) has a first communication function and a second communication function. The first communication function is a function of detecting a short circuit between the pair of electric wires (31, 32) and receiving a fire report notifying the occurrence of a fire. The second communication function is a function of receiving an address for identifying the slave unit (2) by communicating with the slave unit (2) via the pair of electric wires (31, 32). The mode switching unit (171) switches the operation mode of the communication unit (13) between a first mode and a second mode. The first mode is an operation mode of the communication unit (13) for receiving a fire report from the slave unit (2). The second mode is an operation mode of the communication unit (13) in which the first communication function and the second communication function are valid.

  According to this aspect, it is possible to suppress the occurrence of troubles such as communication failure between the master unit (1) and the slave unit (2), and it is possible to construct the automatic fire alarm system (100) in which malfunctions are less likely to occur. Becomes

  In the base unit (1) of the second aspect, in the first aspect, the mode switching unit (171) disables the first communication function and disables the second communication function in the first mode.

  According to this aspect, by switching between enabling and disabling the first communication function, it is possible to suppress occurrence of trouble such as communication failure between the master unit (1) and the slave unit (2). In particular, the mode switching unit (171) may enable both the first communication function and the second communication function in the second mode.

  In the master unit (1) of the third aspect, in the first or second aspect, there are a plurality of communication lines (L1) including a pair of electric wires (31, 32). The mode switching unit (171) switches the operation mode of the communication unit (13) for each communication line group including at least one of the plurality of communication lines (L1).

  According to this aspect, it is possible to switch between operating the communication unit (13) in the first mode and operating in the second mode for each communication line group. Thereby, for example, at the time of renewal of the automatic fire alarm system (100), in the second mode, in order from the communication line group in which the switching from the first slave unit (21) to the second slave unit (22) is completed. Operation can be started.

  In the master unit (1) according to the fourth aspect, in the third aspect, the mode switching unit (171) switches the operation mode of the communication unit (13) for each communication line (L1).

  According to this aspect, it is possible to switch between operating the communication unit (13) in the first mode and operating in the second mode for each communication line (L1). Thereby, for example, at the time of renewal of the automatic fire alarm system (100), the communication line (L1) in which the switching from the first slave unit (21) to the second slave unit (22) has been completed is sequentially performed on the second communication line (L1). The operation in the mode can be started.

  In the master unit (1) according to a fifth aspect, in any one of the first to fourth aspects, the mode switching unit (171) is configured to control the communication unit (13) according to an operation signal corresponding to an operation of the operator. Switch the operation mode.

  According to this aspect, it is possible for the operator (user) to switch the operation mode of the communication unit (13) while checking.

  The master unit (1) according to the sixth aspect is configured to detect a communication status with the slave unit (2) connected to the pair of electric wires (31, 32) in any one of the first to fifth aspects. A detection unit (172) is further provided. The mode switching unit (171) switches the operation mode of the communication unit (13) according to the communication status detected by the detection unit (172).

  According to this aspect, it is possible to save labor of the operator (user).

  In the master unit (1) according to the seventh aspect, in the sixth aspect, the detection unit (172) includes a communication status according to communication with the slave unit (2) via the pair of electric wires (31, 32). Is detected.

  According to this aspect, a separate element (such as a wireless communication device) for detecting the type of the slave unit (2) is not required, and the configuration can be simplified.

  In the master unit (1) according to the eighth aspect, in the seventh aspect, one or more slave units (2) are connected to the pair of electric wires (31, 32). The communication unit (13) sends a reply request signal to the pair of electric wires (31, 32), and sends a reply from the slave (2) that has received the reply request signal among the one or more slaves (2). Receive. The detection unit (172) detects a communication status with the slave (2) based on the number of slaves (2) that have returned a reply to the reply request signal. The mode switching unit (171) switches the operation mode of the communication unit (13) according to the number of slaves (2) that have returned a response.

  According to this aspect, it is possible to grasp the communication status with the slave unit (2) based on the number of the slave units (2) to which the reply has been made.

  An automatic fire alarm system (100) according to a ninth aspect includes the master unit (1) and the slave unit (2) according to any one of the first to eighth aspects.

  According to this aspect, it is possible to provide an automatic fire alarm system (100) in which a failure is unlikely to occur.

  The control method according to the tenth aspect is a method for controlling a master unit (1) connected to a slave unit (2) via a pair of electric wires (31, 32). The master unit (1) includes a communication unit (13) having a first communication function and a second communication function. The first communication function is a function of detecting a short circuit between the pair of electric wires (31, 32) and receiving a fire report notifying the occurrence of a fire. The second communication function is a function of receiving an address for identifying the slave unit (2) by communicating with the slave unit (2) via the pair of electric wires (31, 32). In this control method, the operation mode of the communication unit (13) is divided into a first mode for receiving a fire report from the slave unit (2) and a second mode in which the first communication function and the second communication function are valid. Including switching.

  According to this aspect, it is possible to suppress the occurrence of troubles such as communication failure between the master unit (1) and the slave unit (2), and it is possible to construct the automatic fire alarm system (100) in which malfunctions are less likely to occur. Becomes

  A program according to an eleventh aspect is a program that causes a computer system to execute the control method according to the tenth aspect.

  According to this aspect, it is possible to suppress the occurrence of troubles such as communication failure between the master unit (1) and the slave unit (2), and it is possible to construct the automatic fire alarm system (100) in which malfunctions are less likely to occur. Becomes

  The configurations according to the second to eighth aspects are not indispensable configurations for the parent machine (1) and can be omitted as appropriate.

Reference Signs List 1 master unit 13 communication unit 171 mode switching unit 172 detection unit 2 slave unit 31, 32 pair of electric wires L1 communication line 100 automatic fire alarm system

Claims (11)

A master unit connected to the slave unit via a pair of wires,
A first communication function of receiving a fire report notifying of the occurrence of a fire by detecting a short circuit between the pair of electric wires, and communicating with the slave through the pair of wires to thereby execute the slave A communication unit having a second communication function of receiving an address for identifying
The operation mode of the communication unit,
A first mode for receiving the fire report from the slave unit;
A second mode in which the first communication function and the second communication function are valid;
A mode switching unit for switching with
Comprising,
Parent machine. In the first mode, the mode switching unit enables the first communication function and disables the second communication function.
The master unit according to claim 1. There are a plurality of communication lines including the pair of electric wires,
The mode switching unit, for each communication line group including at least one of the plurality of communication lines, switches the operation mode of the communication unit,
The master unit according to claim 1. The mode switching unit switches the operation mode of the communication unit for each of the communication lines,
The parent device according to claim 3. The mode switching unit switches the operation mode of the communication unit according to an operation signal according to an operation of an operator,
The parent machine according to any one of claims 1 to 4. Further comprising a detection unit for detecting the communication status with the slave unit connected to the pair of electric wires,
The mode switching unit switches the operation mode of the communication unit according to the communication status detected by the detection unit,
A master device according to any one of claims 1 to 5. The detection unit detects the communication status according to communication with the slave unit via the pair of wires,
The parent device according to claim 6. One or more of the slave units are connected to the pair of electric wires,
The communication unit transmits a reply request signal to the pair of electric wires, and receives a reply from the slave unit that has received the reply request signal among the one or more slave units,
The detection unit detects the communication status based on the number of slaves that have sent the reply to the reply request signal,
The mode switching unit switches the operation mode of the communication unit according to the number of the slaves that have returned the response,
The parent device according to claim 7. A parent machine according to any one of claims 1 to 8,
The slave unit;
Comprising,
Automatic fire alarm system. A method of controlling a master unit connected to a slave unit via a pair of wires,
The master unit detects a short circuit between the pair of electric wires, and receives a fire report notifying that a fire has occurred, and communicates with the slave unit via the pair of electric wires. A communication unit having a second communication function of receiving an address for identifying the slave unit,
The control method includes:
Switching the operation mode of the communication unit between a first mode in which the fire report is received from the slave unit and a second mode in which the first communication function and the second communication function are valid.
Control method. Causing the computer system to execute the control method according to claim 10;
program.

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