JP7568941B2 - IP address generation method and air conditioning system - Google Patents

Description

This disclosure relates to a method for generating IP addresses and an air conditioning system.

Conventionally, there is an air conditioning system that is composed of multiple indoor units and outdoor units and a centralized device that centrally controls the outdoor units and indoor units, and each device communicates via a communication line (for example, Patent Document 1). Each device in the air conditioning system communicates using a communication address that is set for each device.

JP 2008-157484 A

The complicated task of setting up communication addresses places a burden on installers and is prone to setting errors.

The purpose of this disclosure is to provide an IP address generation method that can optimally generate a communication address.

An IP address generation method according to one aspect of the present disclosure is a method for generating an IP address of an air-conditioning-related device in a communication network including an extension device, a centralized device, and air-conditioning-related devices communicatively connected via the extension device, the IP address including a higher-level address related to the communication network and a lower-level address related to the air-conditioning-related device, and the IP address is generated based on the higher-level address generated based on an identifier unique to the extension device and the lower-level address generated based on an identifier unique to the air-conditioning-related device.

According to the present disclosure, communication addresses can be generated efficiently.

In one aspect of the present disclosure, a method for generating an IP address converts the identifier of the extension device without processing it or based on a predetermined rule, and assigns it to a predetermined area to generate the upper address.

In this embodiment, a higher-level address that is a unique value within the communication network can be easily and appropriately generated based on an identifier specific to the extension device.

In the method for generating an IP address according to one aspect of the present disclosure, the communication network includes a first communication network for communication between the centralized device and the extension device or between the centralized device, the extension device, and the air conditioning-related device, and a second communication network for communication between the extension device and the air conditioning-related device, the extension device has a first communication interface for communication in the first communication network and a second communication interface for communication in the second communication network, and generates a first IP address in the first communication network using a first upper address generated based on the identifier of the first communication interface, and generates a second IP address in the second communication network using a second upper address generated based on the identifier of the second communication interface.

In this aspect, the extension device is equipped with a first communication interface and a second communication interface, and can function as a router that relays communication between the first communication network and the second communication network. Since the upper addresses in the first communication network and the second communication network are generated based on the identifiers of the communication interfaces corresponding to each communication network, the network configuration can be properly defined. Two IP addresses in the first communication network and the second communication network can be efficiently generated based on the different upper addresses and the identifiers unique to each air conditioning-related device.

The expansion unit functions as a router and transfers only those communications addressed to the centralized device among those received from air conditioning-related devices installed downstream of the expansion unit on the second communication network to the centralized device on the first communication network. Conventionally, when using an expansion unit, management by the centralized device is performed by setting the presence or absence of a filter for the operation code of a command, and the expansion unit transfers only the messages required for the centralized device. In order to switch between the presence or absence of a filter, a specified jumper setting is required for the expansion unit, which makes installation cumbersome. In this embodiment, such jumper setting can be eliminated.

In a method for generating an IP address according to one aspect of the present disclosure, the communication network includes a plurality of the extension units and a plurality of the air conditioning-related devices, and the upper addresses of the plurality of the air conditioning-related devices are generated based on any one of the identifiers in each extension unit.

In this embodiment, a higher-level address in the first communication network is generated based on the identifier of any one of the multiple extension devices in the communication network. Even if multiple extension devices are provided in the communication network, a single higher-level address that defines the first communication network can be preferably generated.

In the method for generating an IP address according to one aspect of the present disclosure, the IP address is an IPv6 address.

In this embodiment, sufficient data space is secured as an address area, making it possible to generate IP addresses based on the identifiers of two different devices.

In the IP address generation method according to one aspect of the present disclosure, the communication network uses an HD-PLC method via low-voltage electric wires.

In this embodiment, power and communication data can be transmitted effectively while simplifying the layout of the communication network.

An air conditioning system according to one aspect of the present disclosure includes an expansion unit, and a control unit that executes a process for generating IP addresses of air conditioning-related equipment in a communication network including a centralized device and air conditioning-related equipment communicatively connected via the expansion unit, the IP addresses including a higher-level address related to the communication network and a lower-level address related to the air conditioning-related equipment, and the control unit generates the IP addresses based on the higher-level address generated based on an identifier unique to the expansion unit and the lower-level address generated based on an identifier unique to the air conditioning-related equipment.

In this embodiment, the communication address can be generated efficiently.

1 is a schematic diagram of an air conditioning system according to an embodiment. 1 is a block diagram showing an example configuration of a centralized device, an outdoor unit, an indoor unit, and an expansion unit of an air conditioning system. FIG. 2 is an explanatory diagram illustrating a communication network configuration of the air conditioning system. FIG. 2 is a diagram for explaining a method for generating a link-local unicast address. FIG. 1 is a diagram for explaining a method for generating a unique local unicast address. FIG. 11 is a sequence diagram showing an example of a procedure for address generation executed by the air conditioning system. FIG. 11 is an explanatory diagram illustrating a communication network configuration of an air conditioning system according to a second embodiment. 13 is a flowchart showing an example of a candidate list generation process executed by the air conditioning system. 13 is a flowchart illustrating an example of an upstream network prefix generation processing procedure. 13 is a flowchart illustrating an example of a processing procedure executed by an air conditioning system according to a third embodiment.

First Embodiment
1 is a schematic diagram of an air conditioning system S according to an embodiment. The air conditioning system S is a system for controlling air conditioning in, for example, an office building, a commercial building, a public facility, etc. The air conditioning system S includes a centralized device 1 and a plurality of air conditioning-related devices 2. The centralized device 1 and each air conditioning-related device 2 are communicatively connected via a communication line 3 to form a communication network.

The centralized equipment 1 is a device that controls the operation of multiple air conditioning-related devices 2, and is, for example, a server computer, a personal computer, a quantum computer, etc. The centralized equipment 1 controls the operation of the air conditioning-related devices 2 to be controlled by sending control signals to the air conditioning-related devices 2 to be controlled. The air conditioning-related devices 2 are devices for performing air conditioning control, and may include, for example, an outdoor unit 21, an indoor unit 22, a ventilation device 23, and an expansion unit 24. Each of the centralized equipment 1, the outdoor unit 21, the indoor unit 22, the ventilation device 23, and the expansion unit 24 may be referred to as "equipment".

A plurality of outdoor units 21 are connected to the centralized device 1 via a communication line 3. The outdoor units 21 may be directly connected to the centralized device 1, or may be indirectly connected to the centralized device 1 via an expansion unit 24. The expansion unit 24 is a device (adapter) for expanding the number of devices connected to the centralized device 1. Usually, the maximum number of outdoor units that can be directly connected to the centralized device 1 is determined. By connecting the expansion unit 24 to the centralized device 1 and connecting a plurality of outdoor units 21 to the expansion unit 24, the total number of outdoor units 21 and indoor units 22 that constitute the air conditioning system S can be increased. The expansion unit 24 functions as a relay device for relaying communication from the centralized device 1 to the outdoor unit 21 or indoor unit 22 connected downstream of the expansion unit 24. Here, downstream means the opposite direction to the centralized device 1 as viewed from the air conditioning-related device 2 such as the expansion unit 24, and upstream means the direction of the centralized device 1 as viewed from the air conditioning-related device 2 such as the expansion unit 24. The direction only indicates the direction of communication, and does not necessarily have to be a hierarchical relationship on the network. For example, they may be connected in parallel to the same subnetwork, or they may be connected via air conditioning-related devices 2 on multiple parallel subnetworks.

One or more indoor units 22 are connected to each outdoor unit 21 via a communication line 3. One or more ventilators 23 may be connected to the outdoor unit 21 via the communication line 3. The outdoor units 21, indoor units 22, and ventilators 23 may be connected in a bus configuration via the communication line 3. The outdoor unit 21 controls its own operation based on a control signal received from the centralized equipment 1. In addition, when the outdoor unit 21 receives a control signal from the centralized equipment 1 addressed to the indoor unit 22 or ventilator 23 connected downstream of the outdoor unit 21, it transmits the control signal to the addressed indoor unit 22 or ventilator 23. The indoor unit 22 or ventilator 23 controls air conditioning based on the control signal received from the centralized equipment 1 via the outdoor unit 21 or directly.

One outdoor unit 21 and the indoor units 22 and ventilation devices 23 connected to the outdoor unit 21 constitute one refrigerant system. Refrigerant circulates between the devices belonging to the same refrigerant system. The indoor units 22 and ventilation devices 23 belonging to the same refrigerant system are each connected via a communication line 3, enabling mutual communication.

In the air conditioning system S, IP communication is performed in a communication network that includes each device, using a communication protocol such as Ethernet (registered trademark) or HD-PLC (High Definition Power Line Communication). In the following, an example is described in which communication between each device via the communication network is performed by HD-PLC, and a power line compatible with PLC communication, particularly a low-voltage power line, is used as the communication line 3.

In the communication network of the air conditioning system S, the range in which communication takes place between devices in the entire network including multiple refrigerant systems is referred to as the overall network, and the range in which communication takes place between air conditioning-related devices 2 within the refrigerant systems is referred to as the intra-system network. Furthermore, in the overall network, the range in which communication takes place upstream of the expansion unit 24 is referred to as the first network, and the range in which communication takes place downstream of the expansion unit 24 is referred to as the second network. Details of the network configuration in the air conditioning system S will be described later.

Figure 2 is a block diagram showing an example configuration of the centralized equipment 1, outdoor unit 21, indoor unit 22, and expansion unit 24 of the air conditioning system S.

The centralized device 1 includes a control unit 11, a memory unit 12, an input/output unit 13, a first communication unit 14, and a second communication unit 15.

The control unit 11 is an arithmetic processing device equipped with a CPU (Central Processing Unit), a GPU (Graphics Processing Unit), etc. The control unit 11 uses built-in memory such as a ROM (Read Only Memory) or a RAM (Random Access Memory), a clock, a counter, etc. to execute various programs stored in the ROM or storage unit, and control the operation of each of the above-mentioned hardware components.

The storage unit 12 includes a non-volatile storage device such as a hard disk, an EEPROM (Electrically Erasable Programmable ROM), or a flash memory. The storage unit 12 stores programs and data referenced by the control unit 11. The storage unit 12 may be composed of multiple storage devices, or may be an external storage device connected to the centralized device 1. Data stored in the storage unit 12 includes, for example, identification information of the device itself (described later), and IP addresses of the device itself and each device connected to the device for communication.

The program (program product) stored in the memory unit 12 may be provided by a non-transitory recording medium (not shown) on which the program is recorded in a readable manner. The recording medium is a portable memory such as a CD-ROM, a USB memory, or a Secure Digital (SD) card. The control unit 11 reads the desired computer program from the recording medium using a reading device (not shown) and stores the read computer program in the memory unit 12. Alternatively, the computer program may be provided by communication.

The input/output unit 13 includes an input/output device for connecting an external device to the device. The external device may include, for example, a display device and an input device (not shown).

The first communication unit 14 includes a communication module (e.g., a network interface card (NIC)) for performing processing related to communication by the first communication protocol. In this embodiment, the first communication protocol is Ethernet, and the first communication unit 14 includes an Ethernet communication module. The second communication unit 15 is connected to the first communication unit 14 via the communication line 3.

The second communication unit 15 includes a communication module (e.g., a NIC) for performing processing related to communication by the second communication protocol. In this embodiment, the second communication protocol is HD-PLC, and the second communication unit 15 includes an HD-PLC communication module. The second communication unit 15 may include a CPU, memory, etc. (not shown). The HD-PLC communication module is assigned a MAC address or a device number, which is device-specific identification information. Note that the second communication unit 15 is not limited to being connected via the first communication unit 14, and may be connected to the control unit 11 via an internal bus or the like. The second communication unit 15 may be disposed outside the centralized device 1, or may be disposed inside the casing that constitutes the centralized device 1.

The second communication unit 15 also functions to perform processing related to power supply. The second communication unit 15 is wired via a power cable (not shown), and supplies power supplied from an external device to a microcomputer including the control unit 11 as drive power.

The control unit 11 transmits and receives information and power to and from each device through the first communication unit 14 and the second communication unit 15. Specifically, the control unit 11 transmits communication data according to the Ethernet protocol to the external device using an IP address through the first communication unit 14. The first communication unit 14 transmits the received communication data to the second communication unit 15. The second communication unit 15 copies the received communication data to an HD-PLC memory (buffer) or the like, and transmits it to the external device according to the HD-PLC protocol. The external device that is the recipient of the communication data receives the received HD-PLC protocol communication data via Ethernet communication by reversing the procedure.

The outdoor unit 21 has the same hardware configuration as the centralized device 1, and includes a control unit 211, a memory unit 212, an input/output unit 213, a first communication unit 214, and a second communication unit 215. The memory unit 212 includes a non-volatile storage device such as a flash memory, and stores various programs and data referenced by the control unit 211. The data stored in the memory unit 212 includes, for example, the identification information of the unit itself, and the identification information or IP addresses of the unit itself and each device connected to the unit for communication. The outdoor unit 21 may also include various mechanisms for controlling air conditioning, such as a compressor, a fan, and a valve.

The program (program product) stored in the memory unit 212 may be provided by a non-transitory recording medium (not shown) on which the program is recorded in a readable manner. The control unit 211 reads the desired computer program from the recording medium using a reading device (not shown) and stores the read computer program in the memory unit 212. Alternatively, the computer program may be provided by communication.

The indoor unit 22 has the same hardware configuration as the centralized device 1, and includes a control unit 221, a memory unit 222, an input/output unit 223, a first communication unit 224, and a second communication unit 225. The memory unit 222 includes a non-volatile storage device and stores various programs and data referenced by the control unit 221. The programs stored in the memory unit 222 include a program 22P for causing the control unit 221 to execute processing related to the generation of an IP address. The data stored in the memory unit 222 includes, for example, the identification information of the unit itself, and the identification information or IP addresses of the unit itself and each device connected to the unit. The indoor unit 22 may also include various mechanisms for controlling air conditioning, such as sensors, fans, valves, and remote controls.

The program (program product) stored in the memory unit 222 may be provided by a non-transitory recording medium 22A on which the program is recorded in a readable manner. The control unit 221 reads the desired computer program from the recording medium 22A using a reading device (not shown), and stores the read computer program in the memory unit 222. Alternatively, the computer program may be provided by communication.

The expansion device 24 includes a control unit 241, a memory unit 242, an input/output unit 243, a first communication unit 244, and a second communication unit 245.

The memory unit 242 stores various programs and data. The programs stored in the memory unit 242 include program 24P for causing the control unit 241 to execute processing related to the generation of IP addresses. The data stored in the memory unit 242 includes, for example, identification information of the device itself, IP addresses and routing tables of the device itself and each device connected to the device for communication, and network prefixes used to generate IP addresses, which will be described later.

The program (program product) stored in the storage unit 242 may be provided by a non-transitory recording medium 24A on which the program is recorded in a readable manner. The control unit 241 reads the desired computer program from the recording medium 24A using a reading device (not shown), and stores the read computer program in the storage unit 242. Alternatively, the computer program may be provided by communication.

2, the expansion device 24 includes two first communication units 244 and two second communication units 245 connected to each of the first communication units 244. One of the second communication units 245 is communicatively connected to the second communication unit 15 of the centralized device 1, and the other second communication unit 245 is communicatively connected to the second communication unit 215 of the outdoor unit 21. The two second communication units 245 are connected via the first communication unit 244 and the control unit 241. The two second communication units 245 may be connected via an internal bus. The control unit 241 communicates with the centralized device 1 side in the first network through the one of the first communication units 244 and the second communication unit 245. The control unit 241 also communicates with the outdoor unit 21 side in the second network through the other of the first communication units 244 and the second communication unit 245. The other hardware configuration of the expansion device 24 is the same as that of the centralized device 1.

In FIG. 2, an example is shown in which the outdoor unit 21 and the centralized equipment 1 are connected via the expansion unit 24, but the outdoor unit 21 may be directly connected to the centralized equipment 1. Although not shown in FIG. 2, the ventilation device 23 may have the same hardware configuration as the indoor unit 22 and may include a control unit, a memory unit, an input/output unit, a first communication unit, a second communication unit, etc.

The communication method and address generation method in the air conditioning system S having the above hardware configuration will be described. In the following specific example, the air conditioning-related equipment 2 for which an IP address is to be generated is an indoor unit 22, and each control unit 221 of the indoor unit 22 functions as a generation unit that generates an IP address. An outdoor unit 21 and an indoor unit 22 (air conditioning-related equipment 2) are provided downstream of the centralized equipment 1, and an expansion unit 24 is provided between the centralized equipment 1 and the outdoor unit 21 as necessary.

Figure 3 is an explanatory diagram explaining the communication network configuration of the air conditioning system S. As described above, the communication network of the air conditioning system S includes an overall network and an intra-system network. Each device communicates in the overall network and the intra-system network using an IPv6 address generated for each device. Hereinafter, the IPv6 address is also simply referred to as the IP address.

The intra-system network is a communication network that allows communication between devices in the refrigerant system. In detail, the intra-system network allows communication between the outdoor unit 21 and each indoor unit 22 that belong to the same refrigerant system. The overall network is a communication network that allows communication between the devices included in the air conditioning system S across the entire communication network, i.e., the intra-system network.

In the air conditioning system S, as described above, an expansion unit 24 is provided between the centralized equipment 1 and the outdoor unit 21 as necessary. The expansion unit 24 is equipped with two HD-PLC communication modules, and divides the entire network into two segments, a first network on the upstream side and a second network on the downstream side. The first network performs communication between the centralized equipment 1, the outdoor unit 21, and the indoor unit 22, or between the centralized equipment 1, the expansion unit 24, the outdoor unit 21, and the indoor unit 22. The second network performs communication between the expansion unit 24 and air conditioning-related equipment such as the outdoor unit 21 or the indoor unit 22 provided downstream of the expansion unit 24. Each air conditioning-related equipment uses an intra-system network when communicating within the same segment, and uses the entire network when communicating across segments (expansion units 24).

When the expansion device 24 is used to expand the maximum number of devices that can be controlled by the centralized device 1, there is a risk that the network bandwidth will become insufficient due to the increase in the number of devices connected in the communication network. In the air conditioning system S, stable communication is achieved by dividing the communication network into segments using the expansion device 24 and relaying communication between different segments between HD-PLC communication modules.

As shown in FIG. 3, the outdoor unit 21 is connected to the centralized equipment 1 directly or via an expansion unit 24. The air conditioning-related equipment 2 generates different types of IP addresses depending on whether or not an expansion unit 24 is present in the communication system to which the equipment belongs. In FIG. 3, the upper side shows an example of a refrigerant system that does not include an expansion unit 24 upstream of the communication system, and the lower side shows an example of a refrigerant system that includes an expansion unit 24 upstream of the communication system.

As shown in the upper part of FIG. 3, if there is no expansion unit 24 between the centralized equipment 1 and the outdoor unit 21, each indoor unit 22a arranged downstream of the outdoor unit 21 generates a link local unicast address, which is a unique IP address within the communication network. As shown by the dashed lines in FIG. 3, the indoor unit 22a communicates in the intra-system network using the link local unicast address, and transmits and receives data between the outdoor unit 21 and other indoor units 22a in the refrigerant system. Also, as shown by the solid lines in FIG. 3, the indoor unit 22a communicates in the entire network using the same link local unicast address, and transmits and receives data between the centralized equipment 1 via the outdoor unit 21 or directly.

As shown in the lower part of FIG. 3, when an extension unit 24 is present between the centralized device 1 and the outdoor unit 21, each indoor unit 22b arranged downstream of the outdoor unit 21 generates a unique local unicast address in addition to the link local unicast address described above. The unique local unicast address is a unique IP address within the communication network and is an address different from the link local unicast address. As shown by the dashed line in FIG. 3, the indoor unit 22b communicates in the intra-system network using the link local unicast address as described above. Also, as shown by the solid line in FIG. 3, the indoor unit 22b communicates in the entire network using the unique local unicast address, and transmits and receives data to and from the centralized device 1 via the outdoor unit 21 and the extension unit 24.

As shown in the upper part of FIG. 3, when an extension unit 24 exists in the communication system to which the indoor unit 22a belongs, the indoor unit 22a may generate a unique local unicast address in addition to the link local unicast address described above. Even if there is no extension unit 24 between the outdoor unit 21 and the centralized equipment 1 of the refrigerant system to which the indoor unit 22a belongs, the indoor unit 22a can generate a unique local unicast address when an extension unit 24 exists upstream of another refrigerant system in the communication network to which the indoor unit 22a belongs. The indoor unit 22a communicates in the entire network using the unique local unicast address, and transmits and receives data between the outdoor unit 21 and the indoor unit 22b downstream of the extension unit 24 via the extension unit 24.

The link-local unicast address and the unique local unicast address are both IPv6 addresses. An IPv6 address has an address field with a bit length of 128 bits. An IPv6 address is composed of a 64-bit network prefix portion that defines a network, and a 64-bit interface identifier that defines a host. The network prefix portion corresponds to the upper address. The interface identifier corresponds to the lower address. The link-local unicast address and the unique local unicast address for the same indoor unit 22 share the same interface identifier, but the network prefix portion is different.

The network prefix in the unique local unicast address differs depending on the network segment to which the indoor unit 22 belongs. The indoor unit 22a communicates in the first network using a unique local unicast address that includes an upstream network prefix that corresponds to the first network (hereinafter also referred to as an upstream unique local unicast address). The indoor unit 22b communicates in the second network using a unique local unicast address that includes a downstream network prefix that corresponds to the second network (hereinafter also referred to as a downstream unique local unicast address).

Figure 4 is a diagram explaining how to generate a link-local unicast address, and Figure 5 is a diagram explaining how to generate a unique local unicast address. The method of generating an IP address will be explained in detail using Figures 4 and 5.

As shown in FIG. 4, the link-local unicast address is composed of a network prefix portion that includes a network prefix that is a predetermined value, and an interface identifier that is based on identification information unique to each indoor unit 22. The network prefix in the link-local unicast address can be a unique value such as "fe80::/64". The network prefix is not limited to a value that is common within the air conditioning system S, and other random values may be used. The network prefix is set, for example, at the time of product shipment or by the installer of the air conditioning system S, and is stored in the memory unit 222 of each indoor unit 22.

The interface identifier is generated using a MAC address, which is an identifier unique to the indoor unit 22. Specifically, the interface identifier is generated based on the MAC address of the HD-PLC communication module of the second communication unit 225 provided in the indoor unit 22. The indoor unit 22 reads out a 48-bit MAC address stored in advance. If the MAC address of the HD-PLC communication module set in advance is not 48 bits, the number of bits may be converted according to a predetermined rule. The interface identifier may be generated based on the machine number of the indoor unit 22, specifically the machine number of the HD-PLC communication module of the second communication unit 225 provided in the indoor unit 22. The machine number may be, for example, a manufacturing number or a serial number.

The indoor unit 22 converts the MAC address of the HD-PLC communication module according to a predetermined rule. The indoor unit 22 may convert the address using a function that takes the MAC address as an argument. The function for address conversion is a function that returns a unique value for the MAC address. As an example, the indoor unit 22 inverts (e.g., from 0 to 1) the bits of a predetermined bit string in the MAC address of the HD-PLC communication module. Although address conversion processing such as bit inversion is not essential, performing address conversion can suppress the occurrence of configuration problems due to duplication of the MAC addresses of the indoor unit 22 and the HD-PLC communication module. The indoor unit 22 may use the MAC address of the HD-PLC communication module as is without processing it.

The indoor unit 22 applies the bit-inverted MAC address as the MAC address for Ethernet communication of the indoor unit 22. In other words, the indoor unit 22 stores the bit-inverted MAC address as the MAC address corresponding to its own microcomputer. The indoor unit 22 uses the 48-bit MAC address to generate a 64-bit interface identifier. The method for generating the interface identifier from the MAC address may use the well-known EUI-64 method.

The interface identifier is not limited to being generated using the MAC address of the HD-PLC communication module in the indoor unit 22, but may be generated using the MAC address of the Ethernet communication module in the indoor unit 22.

The link-local unicast address is generated by assigning the resulting interface identifier to a specific lower region in the address space and the network prefix to a specific higher region.

Next, a method for generating a unique local unicast address will be described. As shown in FIG. 5, a unique local unicast address is composed of a network prefix portion that includes a different network prefix depending on the extension unit 24 that is communicatively connected to the indoor unit 22, and an interface identifier based on the MAC address of the indoor unit 22.

The method for generating an interface identifier for a unique local unicast address is the same as the method for generating an interface identifier for a link-local unicast address.

The network prefix in the unique local unicast address is generated using an identifier specific to the extension unit 24 that exists in the network to which the indoor unit 22 belongs. Specifically, it is generated using the MAC address of the microcomputer included in the extension unit 24. The MAC address of the microcomputer included in the extension unit 24 may be generated based on the MAC address of the HD-PLC communication module included in the extension unit 24 using the same method as described above. The network prefix may also be generated based on the model number of the HD-PLC communication module included in the extension unit 24.

As described above, the extension device 24 has two HD-PLC communication modules. One HD-PLC communication module functions as an upstream HD-PLC communication module that communicates in a first network. The other HD-PLC communication module functions as a downstream HD-PLC communication module that communicates in a second network. A unique MAC address is preset for each HD-PLC communication device. Two network prefixes are generated based on the MAC addresses of the upstream HD-PLC communication and downstream HD-PLC communication modules. The network prefixes may be generated, for example, by the extension device 24.

The upstream MAC address for the microcomputer in the extension unit 24 is generated by bit converting a specific bit string in the MAC address of the upstream HD-PLC communication module. The extension unit 24 may use the MAC address of the upstream HD-PLC communication module without processing it. An 8-bit identifier for identifying the upstream or downstream side is added to the beginning of the generated 48-bit upstream MAC address. The identifier includes, for example, "01" indicating the upstream side or "02" indicating the downstream side.

In addition, a predetermined 8-bit value is added to the beginning of the upstream MAC address that includes the identifier. The predetermined value may include, for example, information for specifying the range of the communication network that uses the generated IP address. In this embodiment, "FD" is added as the predetermined value. This generates a 64-bit upstream network prefix.

The upstream unique local unicast address of the indoor unit 22 is generated by assigning the obtained upstream network prefix to a specified upper region in the address domain and assigning the interface identifier to a specified lower region in the address domain.

In a similar manner, a downstream network prefix is generated based on the MAC address of the downstream HD-PLC communication device of the extension unit 24. The downstream network prefix is combined with the interface identifier to generate a downstream unique local unicast address of the indoor unit 22.

The extension unit 24 transmits the generated upstream network prefix to the indoor unit 22 (indoor unit 22a in the example shown in FIG. 3) belonging to the first network. The indoor unit 22 belonging to the first network generates an upstream unique local unicast address using the upstream network prefix received from the extension unit 24 and an interface identifier based on its own MAC address. The extension unit 24 also transmits the generated downstream network prefix to the indoor unit 22 (indoor unit 22b in the example shown in FIG. 3) belonging to the second network. The indoor unit 22 belonging to the second network generates a downstream unique local unicast address using the downstream network prefix received from the extension unit 24 and an interface identifier based on its own MAC address.

Figure 6 is a sequence diagram showing an example of the address generation processing procedure executed by the air conditioning system S. The following processing may be executed by the control unit 221 according to the program 22P stored in the memory unit 222 of the indoor unit 22 and by the control unit 241 according to the program 24P stored in the memory unit 242 of the expansion unit 24, or may be realized by dedicated hardware circuits (e.g., FPGA or ASIC) provided in each of the control unit 221 and the control unit 241, or may be realized by a combination thereof.

The control unit 221 of the indoor unit 22 generates a MAC address corresponding to its own microcomputer by converting the MAC address related to the HD-PLC communication device of the second communication unit 225 associated with its own microcomputer according to a predetermined rule (step S201). The control unit 221 generates an interface identifier (step S202). The control unit 221 may generate the interface identifier based on the obtained MAC address, for example, by a method according to the EUI-64 standard.

The control unit 221 generates a link-local unicast address by assigning a pre-stored predetermined value as a network prefix to the upper address field and an interface identifier to the lower address field (step S203). The control unit 221 may obtain the network prefix by receiving a network prefix transmitted from an external device such as the outdoor unit 21.

The control unit 241 of the extension device 24 generates an upstream MAC address and a downstream MAC address corresponding to its own microcomputer (step S101). Specifically, the control unit 241 generates the upstream MAC address and the downstream MAC address corresponding to its own microcomputer by converting the MAC addresses related to the HD-PLC communication devices of the second communication unit 245 on the upstream and downstream sides, which are associated with its own microcomputer, according to a predetermined rule.

The control unit 241 adds an extension bit according to a predetermined rule, and generates an upstream network prefix based on the upstream MAC address, and generates a downstream network prefix based on the downstream MAC address (step S102). The control unit 241 stores the generated upstream network prefix and downstream network prefix in the storage unit 242 (step S103).

Based on the information stored in the memory unit 242, the control unit 241 transmits the upstream network prefix or the downstream network prefix to the indoor unit 22 (step S104). In this case, the control unit 241 transmits the upstream network prefix to the indoor unit 22 on the upstream side (first network), and transmits the downstream network prefix to the indoor unit 22 on the downstream side (second network).

The control unit 241 may transmit a network prefix to all indoor units 22 belonging to the same network segment as the expansion unit 24 by RA (Router Advertisement). The control unit 241 may transmit an RA in response to an RS (Router Solicitation) transmitted from the indoor unit 22.

The control unit 221 of the indoor unit 22 receives either the upstream network prefix or the downstream network prefix (step S204). If the extension unit 24 does not exist in the communication system to which the indoor unit 22 belongs, the processes of steps S101 to S104 and step S204 may be omitted.

The control unit 221 determines whether or not an extension unit 24 is present in the communication system (step S205). If it is determined that an extension unit 24 is not present because a network prefix has not been received (step S205: NO), the control unit 221 proceeds to step S207. The control unit 221 may determine that an extension unit 24 is not present by receiving information indicating that an extension unit 24 is not present from the outdoor unit 21, etc.

When it is determined that an extension device 24 exists by receiving the network prefix (step S205: YES), the control unit 221 generates a unique local unicast address using the received network prefix (step S206). In detail, the control unit 221 generates an upstream unique local unicast address by assigning the received upstream network prefix to the upper address region and the interface identifier acquired in step S202 to the lower address region. Alternatively, the control unit 221 generates a downstream unique local unicast address by assigning the downstream network prefix to the upper address region and the interface identifier to the lower address region.

The control unit 221 stores each generated IP address in the storage unit 222 (step S207), and ends the series of processes. The control unit 221 may transmit the generated IP address to each device, such as the expansion unit 24, the outdoor unit 21, or the centralized device 1.

Then, the control unit 221 can perform communication in the entire network using the generated unique local unicast address, and can perform communication in the intra-system network using the link-local unicast address.

The subject of each of the above-mentioned processes is not limited. For example, part of the process executed by the expansion unit 24 may be executed by the indoor unit 22 or the outdoor unit 21, and part of the process executed by the indoor unit 22 may be executed by the expansion unit 24 or the outdoor unit 21. In the above, an example in which the expansion unit 24 executes the network prefix generation process has been described, but for example, the indoor unit 22 or the outdoor unit 21 may execute it. The indoor unit 22 or the outdoor unit 21 receives the upstream or downstream MAC address of the expansion unit 24 transmitted from the expansion unit 24. The indoor unit 22 or the outdoor unit 21 generates a network prefix based on the received upstream or downstream MAC address.

In the above, an example has been described in which the target for generating an IP address is the indoor unit 22, and the indoor unit 22 executes the IP address generation process. The air conditioning-related equipment 2 for which an IP address can be generated is not limited to the indoor unit 22, and may be any of the ventilation device 23, the outdoor unit 21, and the expansion unit 24.

The device for which the IP address is to be generated and the device that performs the IP address generation process may be independent. For example, the extension unit 24 may generate the IP address of the indoor unit 22. The extension unit 24 receives the MAC address or interface identifier of the indoor unit 22 transmitted from the indoor unit 22. The extension unit 24 generates an IP address of the indoor unit 22 based on the received MAC address or interface identifier and a network prefix according to the communication network to which the indoor unit 22 belongs. The extension unit 24 transmits the generated IP address to the indoor unit 22.

In the above process, communication between the expansion unit 24 and the indoor unit 22 may be performed via the outdoor unit 21.

Each time a new indoor unit 22 is added to the refrigerant system, the expansion unit 24 executes the process shown in FIG. 6 between the new indoor unit 22. The new indoor unit 22 generates an IP address based on a network prefix corresponding to the MAC address of the expansion unit 24 and its own MAC address. Indoor units 22 already installed in the refrigerant system can continue to be used without changing the set IP addresses, even when a new indoor unit 22 is added. Maintenance information stored in association with IP addresses can be continuously utilized, improving the maintainability of air conditioning-related equipment.

According to this embodiment, IP addresses are self-generated by the air conditioning-related devices that make up the communication network in the air conditioning system S, eliminating the need for manual address setting work and improving the efficiency of communication address setting work. Each air conditioning-related device can use the IP address to widely send and receive data with external devices in the communication network, allowing for more efficient communication than when communication is performed between specific devices using dedicated addresses that are only valid between specific devices.

Communication in the communication network is performed by the HD-PLC protocol using low-voltage power lines, which allows for efficient transmission of power and communication data while simplifying the layout of the communication network. By using IPv6 addresses as IP addresses, a sufficient data area is secured as an address area, making it possible to generate IP addresses based on the MAC addresses of two different devices.

By using the MAC address or model number of the communication device of each air conditioning-related device, which is set to a unique value within the communication network, it is possible to easily and properly generate identification information specific to the air conditioning-related device. Since an IP address is generated based on identification information that is unique data for the air conditioning-related device, it is possible to reliably associate the air conditioning-related device with an IP address. In addition, a different network prefix is added to the upper part of the IP address depending on whether or not an extension device is present in the communication system to which the air conditioning-related device belongs. The communication network configuration including the extension device can be properly reflected in the IP address of the air conditioning-related device.

Second Embodiment
In the second embodiment, a configuration in which a communication network includes a plurality of extension devices 24 will be described. The following mainly describes the differences from the first embodiment, and the same reference numerals will be used to designate the same components as in the first embodiment, and detailed descriptions thereof will be omitted.

Figure 7 is an explanatory diagram illustrating the communication network configuration of the air conditioning system S of the second embodiment. As shown in Figure 7, the communication network of the second embodiment includes multiple expansion units 24 provided downstream of the centralized equipment 1. In the following, an example will be described in which a first expansion unit 24a, a second expansion unit 24b, and a third expansion unit 24c are included. In the following description, when there is no need to distinguish between the first expansion unit 24a, the second expansion unit 24b, and the third expansion unit 24c, they will also be simply referred to as expansion units 24.

The outdoor unit 21a is connected downstream of the first expansion unit 24a, the outdoor unit 21b is connected downstream of the second expansion unit 24b, and the outdoor unit 21c is connected downstream of the third expansion unit 24c. The indoor unit 22 and the ventilation device 23 (not shown) are connected downstream of the outdoor unit 21a, the outdoor unit 21b, and the outdoor unit 21c, respectively.

The centralized device 1, the first extension device 24a, the second extension device 24b, and the third extension device 24c communicate in the first network of the overall network using upstream unique local unicast addresses. In addition, the extension device 24 and devices such as the outdoor unit 21 and the outdoor unit 21 that are provided downstream of the extension device 24 communicate in the second network of the overall network using downstream unique local unicast addresses.

As described above, the network prefix portion in the upstream unique local unicast address includes an upstream network prefix that defines the first network. The upstream network prefix is generated using the MAC address of the upstream HD-PLC communication module of the extension device 24. Here, if there are multiple extension devices 24 belonging to the first network, and each extension device 24 generates its own upstream network prefix, multiple upstream network prefixes will be set, and communication in the first network will not be performed properly.

In this embodiment, one of the multiple extension devices 24 belonging to the first network is selected, and the selected extension device 24 is set as the representative device. Using the MAC address of the set representative device, one upstream network prefix that defines the first network is generated, and the generated upstream network prefix is shared between each extension device 24.

The method for selecting the representative device is not limited, but for example, the representative device can be selected based on the magnitude relationship of the MAC address values of the upstream HD-PLC communication modules in each extension device 24. In this embodiment, the extension device 24 with the smallest MAC address value is set as the representative device. By determining the representative device based on the magnitude relationship of the MAC address values, the representative device can be easily and reliably identified. The representative device may be the extension device 24 with the largest MAC address value.

Each extension device 24 stores in advance in the memory unit 242 a candidate list of devices connected to the first network. As shown in FIG. 7, the candidate list is data in list format that associates the MAC addresses of the HD-PLC communication modules with device types for devices including at least all extension devices 24 connected to the first network. Device types include centralized equipment, extension devices, outdoor units, indoor units, ventilation devices, etc. The candidate list may store the MAC address or interface identifier of the Ethernet communication module instead of or in addition to the MAC address of the HD-PLC communication module.

Each extension device 24 identifies the smallest MAC address from among those whose device type is an extension device based on the candidate list. The extension device 24 having the identified MAC address becomes the representative device. In the example shown in FIG. 7, the MAC address values are smaller in the order of the first extension device 24a, the second extension device 24b, and the third extension device 24c, and the first extension device 24a becomes the representative device.

The first extension device 24a, which is the representative device, generates an upstream network prefix based on the MAC address of its own upstream HD-PLC communication module. The first extension device 24a transmits the generated upstream network prefix to the other second extension device 24b and third extension device 24c connected to the first network. The second extension device 24b and third extension device 24c receive the upstream network prefix from the first extension device 24a. As a result, the upstream network prefix is shared between the extension devices 24 connected to the first network.

Each extension unit 24 also generates a different downstream network prefix based on the MAC address of its own downstream HD-PLC communication module. For example, a downstream network prefix that defines a second network for communication between the first extension unit 24a and the outdoor unit 21a is generated based on the MAC address of the first extension unit 24a. The first extension unit 24a transmits the generated downstream network prefix to the downstream outdoor unit 21a and indoor unit 22. The outdoor unit 21a and the like use the acquired downstream network prefix to generate a downstream unique local unicast address. Similarly, the second extension unit 24b and the third extension unit 24c each generate a different downstream network prefix based on the MAC address of their own downstream HD-PLC communication module. The generated downstream network prefix is transmitted to downstream devices.

The extension device 24 associates the generated upstream network prefix and downstream network prefix with the MAC address or an interface identifier corresponding to the MAC address of the extension device itself or the outdoor unit 21 installed downstream of the extension device, and stores them together in the memory unit 242. The extension device 24 can generate an IP address for each device based on the information stored in the memory unit 242.

Figure 8 is a flowchart showing an example of a candidate list generation process performed by the air conditioning system S. The following process is executed by the control unit 241 of the first expansion unit 24a and the control unit 241 of the second expansion unit 24b, for example, after the first expansion unit 24a and the second expansion unit 24b are started.

The first extension device 24a acquires the MAC addresses and device types of the HD-PLC communication modules in devices including at least all other extension devices 24 connected to the first network (step S301). The first extension device 24a may acquire the MAC addresses and device types by, for example, receiving the MAC addresses and device types transmitted from each device.

The first extension device 24a generates a candidate list by aggregating the MAC addresses and device types of each device that has been acquired (step S302). The first extension device 24a stores the generated candidate list in the storage unit 242 (step S303).

The second extension device 24b sends a candidate list request to the first extension device 24a (step S304).

The first extender 24a receives the candidate list request (step S305). The first extender 24a transmits the generated candidate list to the second extender 24b (step S306). Note that the first extender 24a may transmit the candidate list to the second extender 24b at a predetermined timing without receiving the candidate list request.

The second extension device 24b receives the candidate list (step S307). The second extension device 24b stores the received candidate list in the memory unit 242 (step S308) and ends the process. The candidate list may be updated as needed in response to the addition of a device connected to the first network. Note that the processes from step S304 onward may be omitted.

Although an example has been described above in which the first extension device 24a generates a candidate list and transmits the candidate list to the second extension device 24b, the extension device 24 that generates the candidate list is not limited to the first extension device 24a. For example, an extension device 24 other than the first extension device 24a, a centralized device 1, or another air conditioning-related device 2 that is designated as the parent device of the first network may generate a candidate list and transmit it to another device connected to the first network.

The candidate list generation process may also be performed for each device. In this case, the processes in steps S301 to S303 described above are performed in each device, including at least all extension devices 24 connected to the first network. Each device acquires the MAC address and device type of the HD-PLC communication module, for example, by broadcasting, and generates an individual candidate list based on the acquired MAC address and device type.

Figure 9 is a flowchart showing an example of a process for generating an upstream network prefix. After obtaining a candidate list, the extender 24 connected to the first network executes the following process.

The control unit 241 of the extension device 24 determines whether the extension device 24 is a representative device (step S401). The extension device 24 refers to the candidate list, extracts all MAC addresses whose device type is an extension device, and identifies the MAC address with the smallest value from among the extracted MAC addresses. The extension device 24 determines whether the identified MAC address matches the MAC address of the extension device.

If the identified MAC address matches the MAC address of the device itself and the device is determined to be the representative device (step S401: YES), the control unit 241 generates an upstream network prefix (step S402). In detail, the control unit 241 generates an upstream network prefix based on the MAC address of the device's upstream HD-PLC communication module, using a procedure similar to that of the first embodiment.

The control unit 241 stores the generated upstream network prefix in the storage unit 242 (step S403). At that time, the control unit 241 associates the upstream network prefix with an interface identifier of the device itself or an outdoor unit 21 or the like that is provided downstream of the device, and stores both in the storage unit 242.

The control unit 241 transmits the upstream network prefix to the other extension devices 24 connected to the first network (step S404). The control unit 241 may transmit a signal indicating the upstream network prefix by RA to all devices including the other extension devices 24 connected to the first network. The control unit 241 may transmit the RA in response to the RS transmitted from the other extension devices 24.

After generating the network prefix, the control unit 241 repeatedly executes the process of step S404 at predetermined intervals. The control unit 241 continues transmitting the network prefix until communication with the first network is disconnected.

On the other hand, if the identified MAC address does not match the MAC address of the device itself and therefore the device itself is determined to be not the representative device (step S401: NO), the control unit 241 does not generate an upstream network prefix and waits until the upstream network prefix is sent from the representative device. In this case, the other extension device 24 performs the above-mentioned processing from step S402 to step S404, and generates a network prefix.

The control unit 241 receives the upstream network prefix by receiving the RA from the representative device (step S405). The control unit 241 stores the received upstream network prefix in the memory unit 242 (step S406). As in step S403, the control unit 241 associates the interface identifier and the like and stores them together in the memory unit 242. The control unit 241 ends the process.

According to this embodiment, a unique upstream network prefix that defines the first network can be easily and appropriately generated using the MAC address of a representative device that represents multiple extension devices 24 connected to the first network. The extension device 24 can appropriately relay communication between the first network and the second network by IP routing without performing complicated jumper settings, etc.

Third Embodiment
In the third embodiment, a configuration will be described in which an extension device 24 different from the representative device functions as the next representative device. The following mainly describes the differences from the first embodiment, and the same reference numerals will be used to designate the same components as the first embodiment, and detailed descriptions thereof will be omitted.

Even if the representative device in the air conditioning system S is disconnected from the communication network due to removal or failure of the representative device, the air conditioning system S continues to use the configured upstream network prefix without changing it.

For example, in the example shown in FIG. 7, if the first extension 24a with the smallest MAC address is removed from the air conditioning system S, the second extension 24b with the second smallest MAC address functions as the next representative device. The second extension 24b transmits an RA of the upstream network prefix instead of the first extension 24a. In this case, the second extension 24b continues to use the upstream network prefix generated using the MAC address of the first extension 24a without changing it.

Furthermore, if the second extension unit 24b is removed from the air conditioning system S, the third extension unit 24c, which has the third smallest MAC address, functions as the next representative device. Similarly, the third extension unit 24c uses the upstream network prefix generated using the MAC address of the first extension unit 24a without changing it.

In this way, the initially set upstream network prefix is used without change until all extension devices 24 that can be representative devices connected to the first network are disconnected.

Figure 10 is a flowchart showing an example of a processing procedure executed by the air conditioning system S of the third embodiment.

The control unit 241 of the extension device 24 determines whether the representative device has been disconnected (step S501). For example, if the control unit 241 receives the next RA within a predetermined time after receiving an RA from the representative device, it determines that the representative device has not been disconnected. If the control unit 241 does not receive the next RA for a predetermined time or more after receiving an RA from the representative device, it determines that the representative device has been disconnected.

If it is determined that the representative device has not been disconnected (step S501: NO), the control unit 241 ends the process. If it is determined that the representative device has been disconnected (step S501: YES), the control unit 241 refers to the candidate list and identifies the next representative device (step S502). The control unit 241 identifies the extension device 24 having the next smallest MAC address after the disconnected representative device as the next representative device.

The control unit 241 compares the MAC address of the identified next representative device with its own MAC address to determine whether the device itself is the next representative device (step S503). If it is determined that the device itself is not the next representative device (step S503: NO), the control unit 241 outputs a notification to the next representative device requesting output of a network prefix (step S504).

The control unit 241 determines whether or not a network prefix has been received from the next representative device (step S505). For example, if it is determined that a network prefix has not been output because an RA has not been received from the next representative device (step S505: YES), the control unit 241 returns the process to step S502 and further identifies the next representative device.

If it is determined that a network prefix has been output by receiving an RA from the next representative device (step S505: NO), the control unit 241 ends the process.

If it is determined that the device itself is the next representative device (step S503: YES), the control unit 241 reads out the upstream network prefix stored in the memory unit 242, and transmits the read upstream network prefix to other extension devices 24 connected to the first network by RA or the like (step S506). The control unit 241 ends the series of processes.

In the above process, when the control unit 241 receives a notification from another extension device 24 requesting output of a network prefix for the next representative device, the control unit 241 may perform the process of step S506 and transmit the upstream network prefix.

In the above-mentioned step S502, the control unit 241 may execute a process to check the communication status of the extension device 24 that can become the representative device. For example, the control unit 241 sends an echo request to the extension device 24 having the next smallest MAC address after the disconnected representative device, and determines whether or not there is an echo response. If the control unit 241 does not receive an echo response, it executes the same process on the extension device 24 having the next smallest MAC address. The control unit 241 may output the echo request a predetermined number of times in succession at a predetermined interval. This makes it possible to suitably identify the next representative device connected to the communication network. If the control unit 241 has identified itself as the next representative device, the above process is not necessary.

According to this embodiment, even if the equipment configuration in the communication network changes, another extension device 24 can function favorably as a representative device in place of the disconnected extension device 24, so there is no need to change the prefix due to the disconnection of the representative device. When a new prefix is generated in response to a change in the equipment configuration in the communication network, communication cannot be performed across the entire communication network until the new prefix is generated and transmitted to each air conditioning-related device. By using the prefix as is, it is possible to prevent such communication failures from occurring and favorably continue communication in air conditioning-related devices other than those downstream of the disconnected representative device.

In each of the above-described embodiments, the entity that performs the network prefix generation process is not limited to the expansion device 24, and may be executed by, for example, the centralized device 1 or an air-conditioning-related device 2 other than the expansion device 24.

The present invention is not limited to these examples, but is intended to include all modifications within the scope of the claims and their equivalent meanings. In addition, at least a portion of each of the above-described embodiments may be arbitrarily combined.
The sequences shown in the above-described embodiments are not limited, and the order of each process may be changed and multiple processes may be executed in parallel, so long as there is no contradiction. The subject of each process is not limited, and the process of each device may be executed by another device, so long as there is no contradiction.

The matters described in each embodiment can be combined with each other. In addition, the independent claims and dependent claims described in the claims can be combined with each other in any and all combinations regardless of the citation format. Furthermore, the claims use a format in which a claim cites two or more other claims (multi-claim format), but this is not limited to this. They may also be written in a format in which multiple claims cite at least one other claim (multi-multi-claim).

S Air conditioning system 1 Central equipment 21 (2) Outdoor unit (air conditioning related equipment)
22 (2) Indoor unit (air conditioning related equipment)
23 (2) Ventilation equipment (air conditioning related equipment)
24 (2) Expansion unit (air conditioning related equipment)
11, 211, 221, 241 Control unit 12, 212, 222, 242 Storage unit 13, 213, 223, 243 Input/output unit 14, 214, 224, 244 First communication unit 15, 215, 225, 245 Second communication unit 22P, 24P Program 22A, 24A Recording medium

Claims (7)

A method for generating IP addresses of air conditioning-related devices in a communication network including an extension device, a centralized device, and air conditioning-related devices communicatively connected via the extension device, the method comprising:
The IP address includes a higher-level address related to the communication network and a lower-level address related to the air conditioning-related device,
The extender generates the upper address based on an identifier unique to the extender;
The extension device transmits the generated upper address to the air conditioning-related device,
The air conditioning-related device generates the IP address based on the upper address generated based on an identifier unique to the expansion device transmitted from the expansion device , and the lower address generated based on an identifier unique to the air conditioning-related device. The IP address generating method according to claim 1 , wherein the extender generates the upper address by converting the identifier of the extender without processing it or based on a predetermined rule and adding it to a predetermined area. The communication network includes a first communication network for communication between the centralized device and the expansion device or between the centralized device, the expansion device, and the air conditioning-related device, and a second communication network for communication between the expansion device and the air conditioning-related device,
the extender includes a first communication interface for communicating in the first communication network and a second communication interface for communicating in the second communication network;
The air conditioning-related equipment includes:
generating a first IP address in the first communications network using a first higher-level address generated based on the identifier of the first communications interface; or
3. The IP address generating method according to claim 1, further comprising: generating a second IP address in the second communication network by using the second higher-level address generated based on the identifier of the second communication interface. The communication network includes a plurality of the expansion units and a plurality of the air conditioning-related devices,
The IP address generating method according to claim 1 , wherein the extension device generates the upper addresses of the plurality of air conditioning-related devices based on any one of the identifiers in each extension device. The method for generating an IP address according to claim 1 , wherein the IP address is an IPv6 address. 6. The method for generating an IP address according to claim 1, wherein the communication network is an HD-PLC system using low-voltage electric wires. The communication network includes an extension device, and a centralized device and an air conditioning-related device communicably connected via the extension device , the centralized device and the air conditioning-related device executing a process for generating an IP address of the air conditioning-related device,
The IP address includes a higher-level address related to the communication network and a lower-level address related to the air conditioning-related device,
The extender generates the upper address based on an identifier unique to the extender;
The extension device transmits the generated upper address to the air conditioning-related device,
The air conditioning-related device generates the IP address based on the upper address generated based on an identifier unique to the expansion device transmitted from the expansion device , and the lower address generated based on an identifier unique to the air conditioning-related device.

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