JP7624335B2 - Fire alarm systems and terminals - Google Patents

Description

The present invention relates to a fire alarm system, and a terminal and control device used in the fire alarm system.

Conventionally, there is known a method for automatically setting addresses to terminals used in a fire alarm system. Patent Document 1 discloses a technique in which, when an address is set to a first terminal, the terminal to which the address has been set generates addresses for other terminals and transmits the generated addresses to the other terminals.

JP 2000-67352 A

In conventional technology, there was a problem that the address generated by the terminal could be the same as an address already being used by another terminal. As a result, when setting addresses, workers had to manually set the addresses for each device, which was time-consuming and prone to setting errors.

The present invention was made in consideration of these points, and aims to make it possible to automatically set different addresses on multiple terminals.

In a first aspect of the fire alarm system of the present invention, the fire alarm system includes a first terminal and a second terminal connected in cascade, and a control device connected to the first terminal, the control device having an address generation unit that generates a plurality of different addresses, and an address transmission unit that sequentially transmits, from the plurality of addresses generated by the address generation unit, a first address to be set in the first terminal, and a second address different from the first address to be set in the second terminal, the first terminal having a first address receiving unit that receives the first address transmitted by the address transmission unit, a first address storage unit that stores the first address received by the first address receiving unit, and a first address storage unit that stores the first address received by the first address receiving unit, and a first address storage unit that stores the first address received by the first address receiving unit, and a second address storage unit that stores the first address received by the first address receiving unit, and a control device and a control device connected to the first terminal in response to the first address being received by the first address receiving unit. The first switching unit switches the state of the first communication path between the first terminal and the second terminal from a limited connection state in which the second address is not transmitted to an unrestricted connection state in which the second address is transmitted, and the second terminal has a second address receiving unit that receives the second address transmitted by the address transmitting unit via the first communication path that the first switching unit has set to an unrestricted connection state, a second address storage unit that stores the second address received by the second address receiving unit, and a second switching unit that switches the state of the second communication path between the first terminal and another terminal downstream of the second terminal from a limited connection state in which the address is not transmitted to the other terminal to an unrestricted connection state in which the address is transmitted to the other terminal in response to the second address receiving unit receiving the second address.

The first switching unit may switch the state of the first communication path from the limited connection state in which the second address is not transmitted to the second terminal via the first communication path and power supplied from the control device is transmitted to the second terminal to the non-limited connection state in which the second address and the power are transmitted to the second terminal.

The first switching unit may have a low-pass filter that blocks signals including the second address and passes DC signals, the first communication path that passes signals including the second address and DC signals, and a switching element that connects the control device and the second terminal via the low-pass filter in the limited connection state and connects the control device and the second terminal via the first communication path in the non-limited connection state.

The first address receiving unit may store the first address received from the control device in the first address storage unit, on condition that the address is not stored in the first address storage unit.

When the first address is stored in the first address storage unit, the first address receiving unit may transmit a response signal to the control device to notify the control device that the first address has been received.

After transmitting the first address, the address transmission unit may transmit the second address after a time has elapsed that is longer than the time required for the first terminal to receive the first address and for the first switching unit to switch the first communication path from the limited connection state to the non-limited connection state.

The control device may further have a setting reception unit that receives a setting for the number of terminals to which the addresses are to be set, and the address transmission unit may sequentially transmit the number of addresses received by the setting reception unit.

The terminal of the second aspect of the present invention is a terminal used in a fire alarm system in a cascade connection between an upstream terminal and a downstream terminal, and has an address receiving unit that receives an address transmitted by a control device of the fire alarm system via the upstream terminal, an address storage unit that stores the address received by the address receiving unit, and a switching unit that switches the communication path between the upstream terminal and the downstream terminal from a limited connection state in which the address is not transmitted to a non-limited connection state in which the address is transmitted in response to the address receiving unit receiving the address.

The third aspect of the present invention is a control device for a fire alarm system, the control device being connected in a cascade and connected via a communication line to the terminal at the end of the cascade among a plurality of terminals that detect the occurrence of a fire, and having an address generating unit that generates a plurality of different addresses and an address transmitting unit that sequentially transmits the plurality of addresses generated by the address generating unit.

The present invention has the effect of making it possible to automatically set different addresses to multiple terminals.

FIG. 1 is a diagram illustrating an example of the configuration of a fire alarm system. FIG. 2 is a diagram illustrating a configuration of a control device. FIG. 2 is a diagram showing the configuration of a terminal. FIG. 2 is a diagram showing an outline of the circuit configuration of a control device and a terminal. FIG. 2 is a sequence diagram showing a processing flow in the fire alarm system. FIG. 2 is a diagram showing a signal flow in a fire alarm system.

[Outline of Fire Alarm System S]
1 is a diagram showing an example of the configuration of a fire alarm system S. The fire alarm system S includes a control device 1 and a plurality of terminals 2. The control device 1 is included in a fire receiver and functions as a control panel. The control device 1 is connected to a plurality of communication lines L, and is connected to a plurality of terminals 2 via the communication lines L.

The control device 1 receives data transmitted by multiple terminals 2. For example, the control device 1 transmits a polling signal including an address for identifying each of the multiple terminals 2, and receives data from the terminal 2 that has received the polling signal.

The control device 1 generates identification information (hereinafter referred to as an address) to be set for each of the multiple terminals 2. The control device 1 sequentially transmits the addresses to be set for each of the multiple terminals 2 via the communication line L.

The multiple terminals 2 are condition detection terminals, such as smoke detectors 2-1 or heat detectors 2-2, for detecting abnormal conditions such as fire, smoke, or strange odors within the facility in which the fire alarm system S is installed. As shown in FIG. 1, the multiple terminals 2 may include a repeater 2-4 connected to a smoke exhaust terminal ER.

The multiple terminals 2 are connected in a cascade configuration. That is, each of the multiple terminals 2 is connected to another terminal 2 on the upstream side, closer to the control device 1, and another terminal 2 on the downstream side, farther from the control device 1. The terminals 2 receive data sent from the control device 1 via the other terminals 2 on the upstream side. However, terminals 2-1 and 2-5 are connected to the control device 1, and receive data directly from the control device 1.

The multiple terminals 2 are each assigned a unique address by receiving an address sent to each terminal from the control device 1. For example, each of the multiple terminals 2 is assigned a unique address 00-FF. The address may be in hexadecimal, decimal, binary, or any other format.

The multiple terminals 2 store the received address. When the multiple terminals 2 receive a polling signal from the control device 1, they compare the address included in the polling signal with the stored address. If the address included in the polling signal matches the stored address, the multiple terminals 2 transmit a response signal including status data indicating the detected state to the control device 1. If the address included in the polling signal does not match the stored address, the multiple terminals 2 do not transmit a response signal including status data indicating the detected state to the control device 1.

In the fire alarm system S, the control device 1 automatically sets addresses to multiple terminals 2. If addresses have not been set to the multiple terminals 2, the control device 1 cannot specify a specific terminal 2 and transmit the address to be set. Therefore, the fire alarm system S is configured so that the terminal 2 most upstream among the multiple terminals 2 for which no address has been set is the first to receive the address transmitted by the control device 1.

The terminal 2 has a switching unit that switches the state of the internal communication path for transmitting data received from the upstream terminal 2 to the downstream terminal 2. A terminal 2 for which no address is set has an internal communication path in a limited connection state in which the address received from the control device 1 or the upstream terminal 2 is not transmitted to the downstream terminal 2. When a terminal 2 in a limited connection state receives an address transmitted by the control device 1, the switching unit switches the internal communication path to a non-restrictive connection state in which the address transmitted next by the control device 1 is transmitted to the downstream terminal 2.

By configuring the multiple terminals 2 in this manner, the terminal 2 on the most upstream side among the multiple terminals 2 for which no address has been set receives the address transmitted from the control device 1 and sets it as its own address. As a result, even in a state in which the addresses of the multiple terminals 2 have not been set, the control device 1 can automatically set addresses to the multiple terminals 2.
The configurations of the control device 1 and the terminal 2 will be described in detail below.

[Configuration of control device 1]
2 is a diagram showing the configuration of the control device 1. The control device 1 has a communication unit 11, a storage unit 12, and a control unit 13. The control unit 13 has an address generation unit 131, a data transmission unit 132, and a response reception unit 133.

The communication unit 11 has a communication interface for communicating with the terminal 2 via the communication line L. The communication unit 11 transmits an address setting command including the address generated by the address generation unit 131 to the terminal 2 via the communication line L. The communication unit 11 receives the address setting response transmitted by the terminal 2, and inputs the address setting response to the response receiving unit 133.

The communication unit 11 transmits a polling signal including the polling data input from the data transmission unit 132 to the terminal 2. The communication unit 11 receives a response signal including status data indicating the status detected by the terminal 2, which is transmitted by the terminal 2 in response to the polling signal. The communication unit 11 inputs the status data included in the response signal to the response reception unit 133.

The storage unit 12 has storage media such as a ROM (Read Only Memory), a RAM (Random Access Memory), and an SSD (Solid State Drive). The storage unit 12 stores programs executed by the control unit 13. The storage unit 12 also stores the addresses of terminals 2 whose addresses have been set, in association with status data received from the terminals 2. The storage unit 12 may store information about multiple terminals 2 (hereinafter referred to as terminal information) set by an administrator of the fire alarm system S, for example. The terminal information includes information unique to the terminal 2 that is different from the address of the terminal 2, such as the type or model name of the terminal 2.

The control unit 13 has, for example, a CPU (Central Processing Unit) and executes various processes. The control unit 13 executes the programs stored in the storage unit 12, thereby functioning as an address generation unit 131, a data transmission unit 132, a response reception unit 133, and a setting acceptance unit 134.

The address generation unit 131 generates a number of different addresses corresponding to a number of terminals 2. The address generation unit 131 inputs the generated addresses to the data transmission unit 132. The address generation unit 131 may generate a number of addresses that differ in value by a predetermined number (for example, 1), or may generate a number of addresses with random values. The address generation unit 131 may receive a setting for the number of terminals from the setting reception unit 134 described below, and generate the set number of addresses.

The address generation unit 131 generates an address that does not overlap with the address of a terminal 2 for which an address has already been set. For example, the address generation unit 131 reads the address of a terminal 2 for which an address has already been set from the storage unit 12, and generates an address different from the read address. By operating in this manner, the address generation unit 131 can prevent the address of a registered terminal 2 from overlapping with the address of the new terminal 2 even when a new terminal 2 is added after addresses have been set for multiple terminals 2.

The data transmission unit 132 transmits various types of data to the terminal 2 via the communication unit 11. The data transmission unit 132 transmits an address setting command including an address to a terminal 2 in which an address is not set, and transmits polling data to a terminal 2 in which an address is set.

When setting an address in the terminal 2, the data transmission unit 132 sequentially transmits the addresses to be set in each terminal 2 from among the multiple addresses generated by the address generation unit 131. As an example, the data transmission unit 132 generates an address setting command including one of the multiple addresses generated by the address generation unit 131, and transmits it to the terminal 2 via the communication unit 11. After transmitting one address, the data transmission unit 132 transmits another address in response to the response reception unit 133 receiving an address setting response from the terminal 2. In this case, the data transmission unit 132 sequentially transmits addresses until the response reception unit 133 no longer receives an address setting response from the terminal 2.

The data transmission unit 132 may be configured to resend the address setting command if the response receiving unit 133 does not receive a normal address setting response even after a predetermined time has elapsed after sending the address. By configuring the data transmission unit 132 in this way, the address setting operation can be completed normally even if the response from the terminal 2 is temporarily delayed for some reason, and the reliability of the system can be improved.

However, not only when addresses have been set for all terminals 2, but also when a terminal 2 is malfunctioning, a state occurs in which the response receiving unit 133 does not receive an address setting response. Thus, when transmitting an address setting response, a terminal 2 that has been set by the administrator of the fire alarm system S to be installed at the most downstream position may transmit information indicating that it is installed at the most downstream position to the control device 1. In this case, the control device 1 transmits addresses sequentially until it receives information indicating that it is installed at the most downstream position from the terminal 2. Furthermore, if the control device 1 does not receive an address setting response for a predetermined period of time or more despite not receiving information indicating that it is installed at the most downstream position, it may display that an error has occurred.

The data transmission unit 132 may sequentially transmit multiple addresses at a predetermined time interval without waiting for an address setting response. The predetermined time interval is, for example, a time equal to or longer than the maximum time required from when the data transmission unit 132 transmits an address until when the response reception unit 133 receives an address setting response. The data transmission unit 132 may sequentially transmit the number of addresses accepted by the setting acceptance unit 134 at a predetermined time interval.

After transmitting an address, the data transmitting unit 132 may transmit the next address after a time period that is longer than the time required for the switching unit to switch the communication path from the limited connection state to the non-limited connection state after the terminal 2 receives the address has elapsed. By configuring the data transmitting unit 132 in this manner, the data transmitting unit 132 can transmit the next address without waiting for the response receiving unit 133 to receive an address setting response, thereby shortening the lead time until the address setting is completed.

The response receiving unit 133 receives the address setting response sent from the terminal 2. The response receiving unit 133 notifies the data sending unit 132 that the address setting response has been received. The response receiving unit 133 stores in the storage unit 12 the address assigned to the terminal 2 that received the address setting response. If the received address setting response includes unique information of the terminal 2 that is different from the address, the response receiving unit 133 may associate the address with the unique information and store them in the storage unit 12.

The setting reception unit 134 accepts the setting of the number of terminals 2 for which addresses are to be set. The setting reception unit 134 notifies the address generation unit 131 of the set number. When the setting reception unit 134 accepts the number of terminals 2, the data transmission unit 132 sequentially transmits the number of addresses accepted by the setting reception unit 134. The setting reception unit 134 may accept input of the number of terminals 2 from an input unit (not shown), or may accept input of the number of terminals 2 from an operation terminal remotely connected via the communication unit 11.

[Configuration of Terminal 2]
3 is a diagram showing the configuration of the terminal 2. The terminal 2 has a communication unit 21, a switching unit 22, a storage unit 23, and a control unit 24. The control unit 24 has an address receiving unit 241 and a switching control unit 242.

The communication unit 21 has a communication interface for communicating with the control device 1 via the communication line L. The communication unit 21 receives an address setting command sent by the control device 1, and inputs the received address setting command to the address receiving unit 241. The communication unit 21 also transmits an address setting response input from the response unit 243 to the control device 1.

The switching unit 22 switches the connection state of the communication path L between a limited connection state and a non-limited connection state. Here, the limited connection state is a state in which a signal transmitted from the control device 1 is not transmitted to the downstream terminal 2, and power supplied from the control device 1 is transmitted to the downstream terminal 2. The non-limited connection state is a state in which both the signal transmitted from the control device 1 and power are transmitted to the downstream terminal 2. For example, in response to the address receiving unit 241 receiving an address, the switching unit 22 switches the state of the communication path L between the control device 1 and the downstream terminal 2 from a limited connection state to a non-limited connection state. The switching unit 22 switches the communication path, for example, in response to the level of a switching signal input from the switching control unit 242.

The storage unit 23 has storage media such as ROM and RAM. The storage unit 23 stores a program executed by the control unit 24. The storage unit 23 stores an address received by the address receiving unit 241. The storage unit 23 may also store unique information of the terminal 2.

The control unit 24 has, for example, a CPU. The control unit 24 functions as an address receiving unit 241 and a switching control unit 242 by executing a program stored in the storage unit 23.

The address receiving unit 241 receives an address setting command including an address transmitted from the control device 1. The address receiving unit 241 determines whether an address has been set by determining whether an address is stored in the memory unit 23. If an address is not stored in the memory unit 23, the address receiving unit 241 stores the address included in the received address setting command in the memory unit 23 as an address to be set in the terminal 2. Furthermore, if an address is stored in the memory unit 23, the address receiving unit 241 does not store the received address in the memory unit 23.

When the address receiving unit 241 stores the address in the memory unit 23, it generates an address setting response indicating that the address has been received and transmits it to the control device 1. After storing the address in the memory unit 23, the address receiving unit 241 may generate an address setting response in response to controlling the switching unit 22 to place the terminal 2 in a non-restrictive connection state, and transmit the address setting response to the control device 1 via the communication unit 21. The address receiving unit 241 may transmit an address setting response including unique information of the terminal 2. When the terminal 2 is installed at the most downstream position, the address receiving unit 241 may transmit an address setting response including information indicating that the terminal 2 is installed at the most downstream position.

The switching control unit 242 controls the switching unit 22 after the address receiving unit 241 receives the address. Specifically, the switching control unit 242 outputs a switching control signal to the switching unit 22 to switch the state of the terminal 2 between a limited connection state and a non-limited connection state.

[Circuit configuration overview]
Fig. 4 is a diagram showing an outline of the circuit configuration of the control device 1 and the terminal 2. In the control device 1 and the terminal 2 shown in Fig. 4, the same components as those in the control device 1 and the terminal 2 shown in Fig. 1 to Fig. 3 are given the same reference numerals, and the description thereof will be omitted. The terminal 2 further has a regulator 25. The regulator 25 generates a voltage for operating the memory unit 23 and the control unit 24 based on the power supplied from the control device 1 through the communication line L.

The switching unit 22 of the terminal 2 has a switching element 221, a switching element 222, a low-pass filter 223, a path 224, and a path 225. The low-pass filter 223 is provided on the path 224, and blocks signals including address setting commands and passes DC signals. In FIG. 4, the paths 224A and 225A of the terminal 2 constitute a first communication path, and the paths 224B and 225B of the terminal 2 constitute a second communication path. The first and second communication paths pass signals including address setting commands and do not pass DC signals in a limited connection state in which the path 224 is used, and pass signals including address setting commands and DC signals in a non-limited connection state in which the path 225 is used.

The switching element 221 switches whether the communication line L between the terminal 2 and the control device 1 or the upstream terminal 2 is connected to the path 224 or the path 225. The switching element 222 switches whether the communication line L between the terminal 2 and the downstream terminal 2 is connected to the path 224 or the path 225. The switching elements 221 and 222 are transistors or relays whose states are switched based on a switching control signal input from the control unit 24, for example.

In a limited connection state, the switching element 221A and the switching element 222A of the terminal 2A connect the control device 1 to the terminal 2B present downstream via the low-pass filter 223A provided on the path 224. When the terminal 2A is in a limited connection state, the address set in the terminal 2A is not transmitted to the terminal 2B via the first communication path, and the power supplied from the control device 1 is transmitted to the terminal 2B.

In a non-restrictive connection state, switching element 221A and switching element 222B of terminal 2A connect the control device 1 to terminal 2B, which is another downstream terminal 2, via path 225A, without going through low-pass filter 223A. The configuration and operation of terminal 2B are the same as those of terminal 2A, except that the device connected upstream is terminal 2A, not control device 1.

[Processing flow in the control device 1 and the terminal 2]
Fig. 5 is a sequence diagram showing the flow of processing in the fire alarm system S. Fig. 6 is a diagram showing the flow of signals in the fire alarm system S. Below, the flow of processing in which the control device 1 sets addresses to multiple terminals 2 will be described with reference to Figs. 5 and 6.

As shown in FIG. 6A, power (61) supplied from the control device 1 to the terminal 2A is supplied to the terminal 2B via the low-pass filter 223A. The regulators 25A and 25B apply a predetermined voltage to the control units 24A and 24B based on the power supplied from the control device 1. The control units 24A and 24B control the switching elements 221A and 222A and the switching elements 221B and 222B, respectively, to set the terminals 2A and 2B to a limited connection state (S0 in FIG. 5).

The control device 1 then generates addresses to be assigned to multiple terminals 2 (S1). Next, the control device 1 transmits an address setting command including the addresses to terminal 2A (S2). In the example shown in FIG. 5, the control device 1 transmits an address setting command (63) including the address "00" to terminal 2A. As shown in FIG. 6B, the address setting command (63) is input to the control unit 24A.

The address setting command (63) is also input to the switching unit 22A. High-frequency components including the address setting command (63) are blocked by the low-pass filter 223A and are not transmitted to the switching element 222A. As a result, the terminal 2B does not receive the address "00" set in the terminal 2A.

The control unit 24A, which has received the address setting command (63), determines whether the address is stored in the memory unit 23A. If the control unit 24A determines that the address is not stored in the memory unit 23A, it stores the address "00" included in the address setting command 63 in the memory unit 23A (S3).

When the control unit 24A stores the address "00" in the memory unit 23A, as shown in FIG. 6C, it inputs a switching control signal (64) to the switching unit 22A to switch the connection state of the switching unit 22A from a limited connection state to a non-limited connection state. The switching element 221A and the switching element 222A switch the connected path from path 224A to path 225A (S4). The control unit 24A transmits an address setting response (65) to the control device 1. Thereafter, the control unit 24A starts detecting the surrounding conditions using a sensor (not shown) (S5).

When the control device 1 receives the address setting response (65), it transmits the address of terminal 2B (S6). In the example shown in FIG. 5, it transmits an address setting command (66) including the address "01" to terminal 2B. As shown in FIG. 6D, the address setting command (66) is input to terminal 2A and terminal 2B.

The control unit 24A of the terminal 2A that receives the address setting command (66) determines whether the address is stored in the memory unit 23A. The control unit 24A determines that the address is stored in the memory unit 23A and discards the received address setting command (66).

The control unit 24B of the terminal 2B that receives the address setting command (66) determines whether the address is stored in the memory unit 23B. As shown in FIG. 6D, if the control unit 24B determines that the address is not stored in the memory unit 23B, it stores the address "01" included in the address setting command (66) in the memory unit 23B (S7).

The address setting command (66) is also input to the switching unit 22B. High-frequency components including the address setting command (66) are blocked by the low-pass filter 223B and are not transmitted to the switching element 222B. As a result, terminal 2 downstream of terminal 2B does not receive the address "01" set in terminal 2B.

When the control unit 24B stores the address "01" in the memory unit 23B, as shown in FIG. 6E, it inputs a switching control signal (67) to the switching unit 22B to switch the connection state of the switching unit 22B from a limited connection state to a non-limited connection state. The switching element 221B and the switching element 222B switch the connected path from path 224B to path 225B (S8). The control unit 24B transmits an address setting response (68) to the control device 1. Thereafter, the control unit 24B starts detecting the surrounding state using a sensor (not shown) (S9). Note that the terminal 2 may start detecting the state after receiving a signal indicating an instruction to start detection from the control device 1.

When the control device 1 receives the address setting response (68), it transmits the address of terminal 2 located downstream of terminal 2B (69), as shown in FIG. 6F. Thereafter, the control device 1 repeats the same process until the termination condition is met.

After setting the addresses, the control device 1 stores the addresses set in each terminal 2 in the storage unit 12. Furthermore, if the address setting is not completed normally, the control device 1 may notify the operator, via a display unit (not shown), that an abnormality has occurred in the address setting.

[Modification]
In the above description, an example has been given in which power is supplied from the control device 1 to the terminal 2 via the communication line L, but the terminal 2 may have a battery and not receive power from the control device 1. In this case, the low-pass filter 223 is not provided in the path 224 of the terminal 2, and in the limited connection state, the switching element 221 and the switching element 222 may be in a non-connected state.

[Effects of Fire Alarm System S]
As described above, in the fire alarm system S, multiple terminals 2 are cascade-connected, and the control device 1 sequentially transmits the addresses to be set to each terminal 2. Then, in the terminal 2, in response to the address reception unit 241 receiving the address, the state of the communication path between the control device 1 or the upstream terminal 2 and the terminal 2 is switched from a limited connection state to a non-limited connection state. By configuring the control device 1 and the terminal 2 in this manner, the control device 1 can automatically set different addresses to the multiple terminals 2 when no addresses are set to the multiple terminals 2. As a result, it is possible to suppress the occurrence of mistakes in setting addresses to the terminals 2 and to improve the work efficiency when installing a large number of terminals 2.

Although the present invention has been described above using embodiments, the technical scope of the present invention is not limited to the scope described in the above embodiments, and various modifications and changes are possible within the scope of the gist of the invention. For example, all or part of the device can be configured by distributing or integrating functionally or physically in any unit. In addition, new embodiments resulting from any combination of multiple embodiments are also included in the embodiments of the present invention. The effect of the new embodiment resulting from the combination also has the effect of the original embodiment.

Reference Signs List 1 Control device 2 Terminal 11 Communication unit 12 Storage unit 13 Control unit 21 Communication unit 22 Switching unit 221 Switching element 222 Switching element 223 Low-pass filter 224 Path 225 Path 23 Storage unit 24 Control unit 131 Address generating unit 132 Data transmitting unit 133 Response receiving unit 134 Setting receiving unit 241 Address receiving unit 242 Switching control unit 243 Response unit

Claims (7)

A fire alarm system comprising a first terminal and a second terminal connected in cascade and a control device connected to the first terminal,
The control device includes:
an address generator that generates a plurality of different addresses;
an address transmission unit that sequentially transmits, from among the plurality of addresses generated by the address generation unit, a first address that is set in the first terminal and a second address that is different from the first address and that is set in the second terminal;
having
The first terminal is
a first address receiving unit that receives the first address transmitted by the address transmitting unit;
a first address storage unit that stores the first address received by the first address receiving unit;
a first switching unit that switches a state of a first communication path between the control device and the second terminal from a limited connection state in which the second address is not transmitted to a non-limited connection state in which the second address is transmitted in response to the first address receiving unit receiving the first address,
a low-pass filter that blocks a signal including the second address and passes a DC signal;
the first communication path through which a signal including the second address and a DC signal pass;
the first switching unit having a switching element that connects the control device and the second terminal via the low-pass filter in the limited connection state and connects the control device and the second terminal via the first communication path in the non-limited connection state;
having
The second terminal is
a second address receiving unit that receives the second address transmitted by the address transmitting unit via the first communication path that the first switching unit has put into the non-restrictive connection state;
a second address storage unit that stores the second address received by the second address receiving unit;
a second switching unit that switches a state of a second communication path between the first terminal and another terminal downstream of the second terminal from the limited connection state in which the address is not transmitted to the other terminal to the non -restrictive connection state in which the address is transmitted to the other terminal in response to the second address being received by the second address receiving unit;
A fire alarm system having: The first switching unit switches the state of the first communication path from the limited connection state in which the second address is not transmitted to the second terminal via the first communication path and power supplied from the control device is transmitted to the second terminal to the non-limited connection state in which the second address and the power are transmitted to the second terminal.
The fire alarm system according to claim 1 . The first address receiving unit stores the first address received from the control device in the first address storage unit on condition that the address is not stored in the first address storage unit.
3. A fire alarm system according to claim 1 or 2 . When the first address is stored in the first address storage unit, the first address receiving unit transmits a response signal to the control device indicating that the first address has been received.
The fire alarm system according to claim 3 . the address transmission unit transmits the second address after a time longer than a time required from when the first terminal receives the first address until when the first switching unit switches the first communication path from the limited connection state to the non-restrictive connection state has elapsed after transmitting the first address;
A fire alarm system according to any one of claims 1 to 4 . The control device further includes a setting receiving unit that receives a setting of the number of terminals to which the addresses are to be set,
The address transmission unit sequentially transmits the addresses in the number accepted by the setting acceptance unit.
A fire alarm system according to any one of claims 1 to 5 . A terminal used in a fire alarm system in a cascade-connected state between an upstream terminal and a downstream terminal,
an address receiving unit that receives an address transmitted by a control device of the fire alarm system via the upstream terminal;
an address storage unit that stores the address received by the address receiving unit;
a switching unit that switches a communication path between the upstream terminal and the downstream terminal from a limited connection state in which the address is not transmitted to a non-limited connection state in which the address is transmitted in response to the address receiving unit receiving the address,
a low-pass filter that blocks signals including the address and passes DC signals;
the communication path through which a signal including the address and a DC signal pass;
a switching element that connects the upstream terminal and the downstream terminal via the low-pass filter in the limited connection state, and connects the upstream terminal and the downstream terminal via the communication path in the non-restrictive connection state;
The switching unit having
A terminal having the above configuration.

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