Relay device, air conditioning related system and communication method

Abstract

To provide a relay device for an air conditioning-related device, which is expectable of suppressing deterioration in communication quality, an air conditioning-related system, and a communication method.SOLUTION: In a communication method according to the form of the present embodiment, a plurality of air conditioning-related devices connected to transmission lines perform multi-hop communication via the transmission lines, and a relay device provided between at least two air conditioning-related devices relays communication by multi-hop. The air conditioning-related devices and the relay device may receive a signal transmitted by another device via the transmission lines, and if the received signal meets a predetermined condition, may transmit the signal to the transmission lines. The transmission lines may include at least three of a power source line, a shared line, and a signal line, and the air conditioning-related devices and the relay device may perform communication in conformity with a communications standard of electric power line communication via the signal line.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present disclosure relates to a communication method for air conditioning-related devices, an air conditioning-related system that employs this communication method, and a relay device used in this communication method. [Background technology]

[0002] In a large-scale air-conditioning-related system, for example, multiple indoor units are connected to one outdoor unit via a transmission line, and multiple outdoor units are further connected via a transmission line to construct a network for communication. By transmitting and receiving various information via the transmission lines between multiple air-conditioning-related devices such as the outdoor unit and the indoor units, centralized control or cooperative operation of the multiple air-conditioning-related devices is realized.

[0003] Patent Document 1 proposes an air conditioner system in which multiple air conditioning units are connected in a daisy chain using a switching hub built into the outdoor unit. In this system, a gateway connected to the switching hub separates data transmission between the centralized transmission line and the internal and external transmission lines. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2008-20092 A Summary of the Invention [Problem to be solved by the invention]

[0005] In large-scale air-conditioning systems, the distances between air-conditioning equipment are long, and there is a concern that signals will be attenuated in the transmission lines connecting the air-conditioning equipment, resulting in a decline in communication quality.

[0006] An object of the present disclosure is to provide a relay device for air conditioning-related devices, an air conditioning-related system, and a communication method that are expected to suppress deterioration of communication quality. [Means for solving the problem]

[0007] A relay device according to one embodiment is provided between a first air conditioning related device and a second air conditioning related device that perform multi-hop communication via a transmission line, and relays the communication through multi-hops.

[0008] The relay device in one embodiment includes a first connection terminal to which a transmission line connected to the first air conditioning-related device is connected, and a second connection terminal to which a transmission line connected to the second air conditioning-related device is connected, and the first connection terminal and the second connection terminal are electrically conductive.

[0009] The relay device according to one embodiment includes a connection terminal to which a transmission line connected to the first air conditioning related device and a transmission line connected to the second air conditioning related device are both connected.

[0010] The relay device according to one embodiment includes a power supply unit that supplies power to a communication unit that performs processing related to multi-hop communication, based on power supplied via the transmission line.

[0011] A relay device according to an embodiment includes a power supply unit that supplies power to a communication unit that performs processing related to multi-hop communication, based on power supplied from a power source external to the device via a power supply line.

[0012] The relay device of one embodiment includes a first communication unit that performs multi-hop communication via the transmission line, and a second communication unit that performs lower frequency communication from the first communication unit via the transmission line.

[0013] In the relay device according to one embodiment, the second communication unit performs communication for acquiring, from another device, identification information required for multi-hop communication by the first communication unit.

[0014] An air conditioning-related system in one embodiment includes a first air conditioning-related device and a second air conditioning-related device that perform multi-hop communication via a transmission line, and a relay device that is connected to the transmission line and is provided between the first air conditioning-related device and the second air conditioning-related device, and that relays the communication via multi-hop.

[0015] In one embodiment of a communication method, a first air conditioning related device and a second air conditioning related device connected to a transmission line perform multi-hop communication via the transmission line, and a relay device connected to the transmission line and provided between the first air conditioning related device and the second air conditioning related device relays the communication via multi-hop.

[0016] In one embodiment of a communication method, the first air conditioning-related device, the second air conditioning-related device, and the relay device receive a signal transmitted by another device via the transmission line, and if the received signal satisfies a predetermined condition, transmit the signal to the transmission line.

[0017] In one embodiment of the communication method, the transmission line includes at least two signal lines, and the first air conditioning related device, the second air conditioning related device, and the relay device communicate via the signal lines in accordance with a communication standard for power line communication.

[0018] In one embodiment of the communication method, the transmission line includes at least three lines: a power line, a shared line, and a signal line, and the first air conditioning-related device, the second air conditioning-related device, and the relay device communicate via the signal lines in accordance with a communication standard for power line communication.

[0019] In one embodiment of the communication method, the length of the transmission line connecting the first air conditioning-related device and the relay device, and the length of the transmission line connecting the second air conditioning-related device and the relay device are 350 meters or less.

[0020] In one embodiment of the communication method, the length of the transmission line connecting the first air conditioning-related device and the relay device, and the length of the transmission line connecting the second air conditioning-related device and the relay device are 200 meters or less.

[0021] According to one embodiment, it is expected that the deterioration of communication quality of air conditioning related devices can be suppressed. [Brief description of the drawings]

[0022] [Figure 1] 1 is a schematic diagram showing a configuration of an air conditioning-related system according to an embodiment of the present invention; [Diagram 2] 1 is a block diagram showing a configuration of an outdoor unit according to an embodiment of the present invention. [Diagram 3] FIG. 2 is a schematic diagram for explaining a multi-hop function. [Figure 4] FIG. 2 is a block diagram showing the configuration of an indoor unit according to the present embodiment. [Diagram 5] 2 is a block diagram showing a configuration of a centralized management device according to the present embodiment; FIG. [Figure 6] 2 is a block diagram showing a configuration of a relay device according to the present embodiment; FIG. [Figure 7] FIG. 2 is a schematic diagram for explaining a connection configuration of air conditioning related devices. [Figure 8] FIG. 11 is a schematic diagram for explaining an upper limit of a transmission distance. [Figure 9] FIG. 11 is a schematic diagram for explaining extension of a communication distance by a relay device. [Figure 10] FIG. 2 is a schematic diagram for explaining an example of an arrangement of relay devices; [Figure 11] FIG. 13 is a schematic diagram for explaining a connection configuration of air conditioning-related devices according to a modified example. [Figure 12] FIG. 13 is a block diagram showing another configuration of the relay device. [Figure 13] FIG. 11 is a schematic diagram for explaining an example of power supply to a relay device. [Figure 14] FIG. 13 is a schematic diagram for explaining another example of power supply to a relay device. [Figure 15] FIG. 13 is a block diagram showing another configuration of the relay device. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0023] Specific examples of the air conditioning-related system according to the present embodiment will be described below with reference to the drawings. Note that the present technology is not limited to these examples, but is defined by the claims, and is intended to include all modifications within the meaning and scope of the claims.

[0024] <System configuration> 1 is a schematic diagram showing the configuration of an air conditioning-related system according to this embodiment. The air conditioning-related system according to this embodiment is a system in which a plurality of air conditioning-related devices are connected via transmission lines (communication lines, communication cables) and communicate with each other via the transmission lines. The air conditioning-related devices may include, for example, a centralized management device 1, an outdoor unit 3, an indoor unit 5, and a relay device 7. However, the air conditioning-related devices are not limited to the above, and may include various devices related to air conditioning (air conditioning), such as a ventilation device, a remote control, a communication device, or a control device.

[0025] In the illustrated air conditioning-related system, one centralized control device 1 and multiple outdoor units 3 are connected via a transmission line. In the air conditioning-related system according to this embodiment, multiple air conditioning-related devices are connected in a daisy chain system. That is, a first outdoor unit 3 is connected to the centralized control device 1 via a first transmission line, a second outdoor unit 3 is connected to the first outdoor unit 3 via a second transmission line, and a third outdoor unit 3 is connected to the second outdoor unit 3 via a third transmission line. However, the multiple transmission lines connecting one centralized control device 1 and multiple outdoor units 3 are electrically conductive. For this reason, if there is no attenuation of signals on the transmission lines, for example, a signal transmitted by the centralized control device 1 can be received by all outdoor units 3 connected in the daisy chain system, and a signal transmitted by any outdoor unit 3 can be received by the centralized control device 1 and all other outdoor units 3.

[0026] Furthermore, in the illustrated air conditioning-related system, multiple indoor units 5 are connected in a daisy chain manner via transmission lines to each outdoor unit 3. That is, a first indoor unit 5 is connected to one outdoor unit 3 via a first transmission line, and a second indoor unit 5 is connected to the first indoor unit 5 via a second transmission line. The multiple transmission lines connecting the outdoor unit 3 and the multiple indoor units 5 are electrically connected, and a signal transmitted by any one of the devices can be received by all of the devices connected in the daisy chain manner.

[0027] Each outdoor unit 3 is connected to a transmission line for communicating with the centralized control device 1 and other outdoor units 3, and a transmission line for communicating with the indoor units 5. In this embodiment, these two transmission lines are electrically connected inside the outdoor units 3. Therefore, for example, the centralized control device 1 can communicate with the indoor units 5 via the outdoor units 3. Also, for example, the indoor unit 5 connected to the first outdoor unit 3 can communicate with the other indoor units 5 connected to the second outdoor unit 3 via the first outdoor unit 3 and the second outdoor unit 3. However, the transmission line for communicating with the centralized control device 1 and other outdoor units 3 and the transmission line for communicating with the indoor units 5 may be electrically disconnected inside the outdoor unit 3.

[0028] In the air-conditioning-related system according to the present embodiment, the multiple air-conditioning-related devices connected in a daisy chain system can include a relay device 7. The relay device 7 is provided between two air-conditioning-related devices that should be directly connected via a transmission line, for example, when the distance between the two air-conditioning-related devices is long and the length of the transmission line exceeds a predetermined length. In the illustrated example, two relay devices 7 are used in the air-conditioning-related system, and each relay device 7 is provided between two indoor units 5. That is, the relay device 7 is connected to the first indoor unit 5 via a first transmission line, and the second indoor unit 5 is connected to the relay device 7 via a second transmission line.

[0029] The relay device 7 may be provided anywhere in the air conditioning-related system. For example, the relay device 7 may be provided between the centralized control device 1 and the outdoor unit 3, or between two outdoor units 3, or between the outdoor unit 3 and the indoor unit 5. A plurality of relay devices 7 may be provided between two air conditioning-related devices.

[0030] <Device configuration> FIG. 2 is a block diagram showing the configuration of the outdoor unit 3 according to this embodiment. However, in this figure, functional units related to communication of the outdoor unit 3 are extracted and illustrated. The outdoor unit 3 according to this embodiment is configured with a control unit 31, a storage unit 32, a communication unit 33, and three connection terminals 34 to 36, etc. The control unit 31 is configured using an arithmetic processing device such as a CPU (Central Processing Unit) or an MPU (Micro-Processing Unit). The control unit 31 can perform various processes by reading and executing a program stored in the storage unit 32. In this embodiment, the control unit 31 performs various control processes such as control of the operation of each unit of the outdoor unit 3 and control of communication with the centralized management device 1, other outdoor units 3, indoor units 5, etc.

[0031] The storage unit 32 is configured using a non-volatile memory element such as a flash memory or an EEPROM (Electrically Erasable Programmable Read Only Memory), etc. The storage unit 32 stores various programs executed by the control unit 31 and various data necessary for the control processing of the control unit 31.

[0032] The communication unit 33 is configured using, for example, a transceiver IC (Integrated Circuit) or the like. The communication unit 33 communicates with the centralized control device 1, the other outdoor units 3, and the indoor units 5 via transmission lines connected to a plurality of connection terminals 34 to 36 provided in the outdoor unit 3. In this embodiment, the communication unit 33 modulates data to be transmitted and received using an OFDM (Orthogonal Frequency Division Multiplexing) method. As a result, the communication unit 33 performs multi-carrier transmission using a frequency band of, for example, 2 to 28 MHz. The communication unit 33 transmits data by outputting a signal obtained by modulating transmission data provided by the control unit 31 to the transmission line, and also obtains and demodulates the signal on the transmission line to obtain data and provides the data obtained as received data to the control unit 31.

[0033] Moreover, the communication unit 33 according to this embodiment has a multi-hop function. The multi-hop function is a function in which a device that receives a signal transmitted by another device via a transmission line outputs the received signal to the transmission line. FIG. 3 is a schematic diagram for explaining the multi-hop function, and is a graph with the horizontal axis representing the transmission distance and the vertical axis representing the signal strength. When the position of the transmitting communication device is set as the transmission distance 0, the strength of a signal transmitted from a certain communication device to the transmission line attenuates as the distance (transmission distance) that the signal travels on the transmission line increases. The device 1 that receives this signal can increase the signal strength of the signal by transmitting (hopping) the same signal as the received signal to the transmission line. The process of transmitting the received signal to the transmission line is performed in sequence by the devices 2, 3, ... connected to the transmission line, thereby extending the transmission distance of the signal.

[0034] The three connection terminals 34-36 are configured using electronic components such as connectors or sockets, and a transmission line for communication is detachably connected to them. In the outdoor unit 3 according to this embodiment, the three connection terminals 34-36 are electrically connected to each other via, for example, a wiring pattern on a circuit board, and are electrically connected to the communication unit 33. Therefore, a signal input from any of the connection terminals 34-36 is output from the other connection terminals 34-36 and input to the communication unit 33. Furthermore, a signal output from the communication unit 33 is output from the connection terminals 34-36. In this embodiment, the three connection terminals 34-36 are directly connected to each other via a wiring pattern or the like, but for example, a filter circuit or the like may be provided between the connection terminals 34-36. The number of connection terminals provided in the outdoor unit 3 may be two or less, or four or more.

[0035] FIG. 4 is a block diagram showing the configuration of the indoor unit 5 according to this embodiment. However, in this figure, functional units related to communication of the indoor unit 5 are extracted and illustrated. The indoor unit 5 according to this embodiment is configured with a control unit 51, a storage unit 52, a communication unit 53, and two connection terminals 54, 55, etc. The control unit 51 is configured using an arithmetic processing device such as a CPU or an MPU. In this embodiment, the control unit 51 performs various control processes such as control of the operation of each unit of the indoor unit 5, and control of communication with the centralized management device 1, the outdoor unit 3, and other indoor units 5, etc. The storage unit 52 is configured using a non-volatile memory element such as a flash memory or an EEPROM. The storage unit 52 stores various programs executed by the control unit 51 and various data required for the control process of the control unit 51.

[0036] The communication unit 53 is configured using, for example, a transceiver IC. The communication unit 53 has the same function as the communication unit 33 of the outdoor unit 3, and the same or similar IC as the IC used for the communication unit 33 of the outdoor unit 3 can be used. The communication unit 53 has a modulation function using the OFDM method and a multi-hop function, and communicates with the centralized control device 1, the outdoor unit 3, other indoor units 5, the relay device 7, etc. through a transmission line connected to the connection terminals 54, 55 of the indoor unit 5. The communication unit 53 transmits data by outputting a signal obtained by modulating transmission data provided by the control unit 51 to the transmission line, and provides the data obtained by acquiring and demodulating the signal on the transmission line to the control unit 51 as received data.

[0037] The two connection terminals 54, 55 are configured using electronic components such as connectors or sockets, and a transmission line for communication is detachably connected to the connection terminals 54, 55. The connection terminals 54, 55 are electrically conductive, for example, via a wiring pattern on a circuit board, and are electrically connected to the communication unit 53. The number of connection terminals included in the indoor unit 5 may be one, or three or more.

[0038] FIG. 5 is a block diagram showing the configuration of the centralized control device 1 according to this embodiment. The centralized control device 1 according to this embodiment is configured to include a control unit 11, a storage unit 12, a communication unit 13, a display unit 14, an operation unit 15, and a connection terminal 16. The control unit 11 is configured using an arithmetic processing device such as a CPU or an MPU. In this embodiment, the control unit 11 performs various control processes such as control of the operation of each unit of the centralized control device 1 and control of communication with the outdoor unit 3 and the indoor unit 5. The storage unit 12 is configured using a non-volatile memory element such as a flash memory or an EEPROM, or a magnetic storage device such as a hard disk. The storage unit 12 stores various programs executed by the control unit 11 and various data required for the control process of the control unit 11.

[0039] The communication unit 13 is configured using, for example, a transceiver IC. The communication unit 13 has the same functions as the communication unit 33 of the outdoor unit 3 and the communication unit 53 of the indoor unit 5, and the same or similar ICs as those used for the communication unit 33 of the outdoor unit 3 and the communication unit 53 of the indoor unit 5 can be used. The communication unit 13 has a modulation function using the OFDM method and a multi-hop function, and communicates with the outdoor unit 3, the indoor unit 5, the relay device 7, and the like through a transmission line connected to a connection terminal 16 provided in the centralized management device 1. The communication unit 13 transmits data by outputting a signal obtained by modulating transmission data provided by the control unit 11 to the transmission line, and also obtains and demodulates the signal on the transmission line to obtain data and provides the data obtained as received data to the control unit 11.

[0040] The display unit 14 is configured using a liquid crystal display or the like, and displays various images and characters, etc., according to the control of the control unit 11. The operation unit 15 accepts user operations and notifies the control unit 11 of the accepted operations. For example, the operation unit 15 accepts user operations using input devices such as mechanical buttons or a touch panel provided on the surface of the display unit 14. For example, the operation unit 15 may be input devices such as a mouse and a keyboard, and these input devices may be configured to be removable from the centralized management device 1. The connection terminal 16 is configured using electronic components such as a connector or a socket, and a transmission line for communication is detachably connected to the connection terminal 16. The connection terminal 16 is electrically connected to the communication unit 13, for example, via a wiring pattern on a circuit board. The centralized management device 1 may have two or more connection terminals.

[0041] FIG. 6 is a block diagram showing the configuration of the relay device 7 according to this embodiment. The relay device 7 according to this embodiment is configured to include a communication unit 71 and two connection terminals 72, 73, etc. The communication unit 71 is configured using, for example, a transceiver IC or the like. The communication unit 71 has the same functions as the communication unit 33 of the outdoor unit 3, the communication unit 53 of the indoor unit 5, and the communication unit 13 of the centralized control device 1, and the same or similar ICs may be used as the ICs used therein. The communication unit 71 has a modulation function using the OFDM method and a multi-hop function, and communicates with the centralized control device 1, the outdoor unit 3, the indoor unit 5, etc. through a transmission line connected to the connection terminals 72, 73 of the relay device 7. However, the communication unit 71 of the relay device 7 only needs to have at least a multi-hop function, and may not have a modulation function using the OFDM method.

[0042] The two connection terminals 72, 73 are configured using electronic components such as connectors or sockets, and a transmission line for communication is detachably connected to the connection terminals 72, 73. The connection terminals 72, 73 are electrically connected to each other via a wiring pattern on a circuit board, for example, and are electrically connected to the communication unit 71. The number of connection terminals included in the relay device 7 may be one or three or more.

[0043] <Communication method> In the air conditioning-related system according to this embodiment, a centralized control device 1, an outdoor unit 3, an indoor unit 5, a relay device 7, and other air conditioning-related devices are connected in a daisy chain manner via transmission lines, and perform multi-carrier communication using the OFDM modulation method. The transmission lines connecting the air conditioning-related devices are electrically connected, and a signal transmitted by one air conditioning-related device can be received by all the other air conditioning-related devices. Each air conditioning-related device has a multi-hop function that outputs the same signal as the signal it received to the transmission line, and increases the transmission distance of the signal by increasing the strength of the signal, which attenuates depending on the transmission distance from the transmission source.

[0044] The OFDM modulation and multi-hop function are used as a communication method, for example, HD-PLC (High Definition Power Line Communication). Therefore, the communication unit 13 of the centralized control device 1, the communication unit 33 of the outdoor unit 3, the communication unit 53 of the indoor unit 5, and the communication unit 71 of the relay device 7 can be configured using a transceiver IC that employs the HD-PLC communication method, for example. Note that while the HD-PLC communication method is for communication via power lines, in the air conditioning-related system according to this embodiment, each air conditioning-related device does not communicate via power lines, but rather communicates via a transmission line provided separately from the power lines.

[0045] FIG. 7 is a schematic diagram for explaining the connection configuration of air conditioning related devices. In this figure, the connection configuration is illustrated using an indoor unit 5 as an example of air conditioning related devices, but the same applies to the other centralized control device 1, outdoor unit 3, and relay device 7. In the air conditioning related system according to this embodiment, two air conditioning related devices are connected using a transmission line 90 that bundles three electric wires, a power line 91, a signal line 92, and a shared line 93. The power line 91 is an electric wire for supplying power from a power source to each air conditioning related device. The signal line 92 is an electric wire for transmitting a signal for communication between the air conditioning related devices. The shared line 93 is an electric wire for defining a reference potential.

[0046] A second air conditioning-related device is connected to a first air conditioning-related device via a first transmission line 90, a third air conditioning-related device is connected to the second air conditioning-related device via a second transmission line 90, a fourth air conditioning-related device is connected to the third air conditioning-related device via a third transmission line 90, and so on, in such a manner that a plurality of air conditioning-related devices are connected in a daisy chain manner. Each electric wire included in the plurality of transmission lines 90 connected to the air conditioning-related devices is electrically connected within the air conditioning-related device. That is, a power supply line 91 of the first transmission line 90 connected to the air conditioning-related device is electrically connected to a power supply line 91 of the second transmission line 90 within the air conditioning-related device. A signal line 92 of the first transmission line 90 connected to the air conditioning-related device is electrically connected to a signal line 92 of the second transmission line 90 within the air conditioning-related device. The shared line 93 of the first transmission line 90 connected to the air conditioning-related device is electrically connected to the shared line 93 of the second transmission line 90 within this air conditioning-related device.

[0047] In the air conditioning-related system according to this embodiment, each air conditioning-related device communicates via a signal line 92 of a transmission line 90. However, the air conditioning-related system may be configured to communicate via a power line 91 using power line communication, in which case the air conditioning-related devices may be connected via a transmission line that bundles together two electric wires, the power line 91 and the shared line 93. The transmission line 90 may also include three electric wires, the power line 91, the signal line 92, and the shared line 93, in addition to one or more other electric wires.

[0048] Moreover, in the air conditioning-related system according to this embodiment, each air conditioning-related device has a multi-hop function and performs a process of outputting the same signal as the received signal to the transmission line (hereinafter, this process is called hop). Note that it is not necessary for all air conditioning-related devices included in the air conditioning-related system to hop; for example, only air conditioning-related devices that receive signals with low strength may hop (however, all air conditioning-related devices may always hop). The following several methods can be adopted as a method for each air conditioning-related device to decide whether or not to hop.

[0049] (1) Designers, etc. are selected For example, whether or not to hop may be set in advance for each air-conditioning-related device included in the air-conditioning-related system. A designer or installer of the air-conditioning-related system sets whether or not to hop for each air-conditioning-related device, for example, depending on the length of the transmission line between the air-conditioning devices or the surrounding noise environment. Depending on this setting, each air-conditioning-related device determines whether or not to hop. When setting, the designer or installer can transmit and receive test signals in the air-conditioning-related system, measure the strength of the received signal in each air-conditioning-related device or the communication speed at which each air-conditioning-related device can communicate, and determine for each air-conditioning-related device whether or not to hop based on the measurement results.

[0050] (2) Air conditioning system is decided For example, each air conditioning-related device in an air conditioning-related system may cooperate to send and receive test signals at a predetermined timing (for example, when the system starts operating after installation, or periodically such as once a month), and each air conditioning-related device may measure the strength of the received signal or the communication speed at which communication is possible, and each air conditioning-related device may decide whether or not to hop based on the measurement results.

[0051] For example, in the HD-PLC communication method, each air conditioning-related device measures the communication speed (PHY Rate) at which it can communicate, and decides whether or not to hop based on whether or not this communication speed exceeds a threshold. Each air conditioning-related device decides not to hop if the communication speed exceeds the threshold, and decides to hop if the communication speed does not exceed the threshold.

[0052] (3) Air conditioning equipment is dynamically determined For example, each air-conditioning related device may measure the strength of a signal each time it receives the signal, and determine whether or not to hop based on whether or not the measured strength exceeds a threshold. Each air-conditioning related device may determine not to hop if the signal strength exceeds the threshold, and may determine to hop if the signal strength does not exceed the threshold. In this case, whether or not to hop may be determined each time a signal is received. In this case, each air-conditioning related device may measure, for example, RSSI (Received Signal Strength Indication) or CINR (Carrier to Interference and Noise Ratio) and compare it with the threshold. The threshold may be appropriately determined based on the configuration of the air-conditioning related system, etc.

[0053] The method for determining whether or not each air conditioning-related device will hop is not limited to the above three methods (1) to (3), and any other method may be used.

[0054] Furthermore, in the air conditioning-related system according to this embodiment, an upper limit is set for the transmission distance (i.e., the length of the transmission line) to prevent the signal strength from attenuating as the transmission distance from the signal source increases, making it impossible to maintain communication between the air conditioning-related devices. Fig. 8 is a schematic diagram for explaining the upper limit of the transmission distance, and shows a graph of the results of measuring the correspondence between the length of the transmission line (wiring length) and the communication speed (PHY Rate). In this graph, the horizontal axis is the wiring length [m] and the vertical axis is the PHY Rate [Mbps], with the thick solid line showing the measurement results when the air conditioning-related devices are not operating, and the thin solid line showing the measurement results when the air conditioning-related devices are operating.

[0055] First, a steady-state operation was performed in an air conditioning-related system connected to 200 air conditioning-related devices, and communication was performed between the air conditioning-related devices to measure the relationship between the communication speed (PHY Rate) and the presence or absence of communication abnormalities. In this measurement, communication was possible without abnormalities when a PHY Rate of 55 Mbps was ensured, but an abnormality occurred in which communication packets could not be received at a PHY Rate below that. For this reason, in the air conditioning-related system according to this embodiment, the lower limit of the PHY Rate in communication is set to 55 Mbps. In the graph shown in the figure, this lower limit of the PHY Rate is indicated by a horizontal dashed line.

[0056] Next, the communication speed (PHY Rate) that can be communicated when two air conditioning related devices are directly connected by a transmission line and communicated was measured by changing the length of the transmission line (wiring length). The measurement results are shown by the broken lines in the graph shown in the figure. When communication is performed without the air conditioning related devices operating, the measurement results show that the PHY Rate reaches the lower limit of 55 Mbps or more when the wiring length is 350 m or less (see the thick solid broken line). From these measurement results, the upper limit of the length of the transmission line in the air conditioning related system according to this embodiment is "350 m" in an environment with little influence of noise, for example.

[0057] When communication was performed while the air conditioning equipment was in air conditioning operation, the PHY Rate deteriorated, as shown by the measurement results in the thin solid broken line in the graph. This is thought to be due to the influence of self-noise from inverters or switching power supplies that are operated by the air conditioning equipment in air conditioning operation, and the deterioration amounted to about 40 Mbps. In reality, in addition to the self-noise of the air conditioning equipment, various influences such as crosstalk from other transmission lines, branch attenuation due to branching of the transmission line, load attenuation due to the input impedance of the air conditioning equipment, and characteristic changes due to deterioration of the transmission line may further deteriorate the PHY Rate.

[0058] Therefore, in the air conditioning-related system according to the present embodiment, the upper limit of the wiring length is set so that the safety factor S exceeds 2.25, based on the measurement results when communication is performed without operating the air conditioner, taking into consideration the deterioration of the PHY rate of about 40 Mbps due to self-noise and deterioration due to other factors. In the graph shown in the figure, the PHY rate is 125 Mbps when the wiring length is 200 m, and the safety factor S = 125 Mbps / 55 Mbps ≈ 2.27. Therefore, the length of the transmission line in the air conditioning-related system according to the present embodiment is set to the upper limit of "200 m". However, in a system that requires a higher safety factor S, the upper limit of the transmission line may be shorter, and in a system that allows a lower safety factor S, the upper limit of the transmission line may be longer than this.

[0059] In the air-conditioning-related system according to this embodiment, as described above, the length of the transmission line connecting the air-conditioning-related devices is limited to 200 m, but depending on the locations where the air-conditioning-related devices are installed, the distance between two air-conditioning-related devices may be greater than 200 m. In the air-conditioning-related system according to this embodiment, when a transmission line longer than the upper limit of 200 m is required, one or more relay devices 7 are provided between the two air-conditioning-related devices.

[0060] FIG. 9 is a schematic diagram for explaining the extension of the communication distance by the relay device 7. The upper part of FIG. 9 illustrates a case where two indoor units 5 are installed as air conditioning-related equipment at a distance of 300 m. In this case, if the two indoor units 5 are directly connected with one transmission line, the length of the transmission line exceeds the upper limit of 200 m. Therefore, by providing one relay device 7 between the two indoor units 5, connecting the first indoor unit 5 and the relay device 7 with a first transmission line, and connecting the relay device 7 with the second indoor unit 5 with a second transmission line, the length of each transmission line can be made 150 m.

[0061] In this example, 300 m is equally divided into two, and the length of the transmission line connecting the relay device 7 and each indoor unit 5 is 150 m, but it does not have to be equally divided into two, and it may be divided into, for example, 200 m and 100 m. As long as the length of one transmission line is 200 m or less, it may be divided in any way.

[0062] 9 shows a case where two indoor units 5 are installed 2000 m apart. In this case, nine relay devices 7 are installed every 200 m between three indoor units 5, which are connected in sequence with a 200 m transmission line and hopped at the relay devices 7, enabling communication between the two indoor units 5 separated by 2000 m.

[0063] In the illustrated example, nine relay devices 7 are provided between the two indoor units 5, but the present invention is not limited to this and ten or more relay devices 7 may be provided between the two indoor units 5. The upper limit on the number of relay devices 7 that can be provided between the two indoor units 5 may be determined according to, for example, the maximum number of hops in the communication method (standard).

[0064] <Summary> In the air conditioning-related system according to the present embodiment having the above configuration, a plurality of air conditioning-related devices, such as the centralized control device 1, outdoor unit 3, and indoor unit 5, connected to a transmission line, perform multi-hop communication via the transmission line. As a result, in the air conditioning-related system, the air conditioning-related devices can hop to increase the signal strength of a signal whose strength attenuates according to the transmission distance, which is expected to suppress deterioration in communication quality and to extend the transmission distance of signals related to communication.

[0065] Furthermore, in the air conditioning-related system according to this embodiment, relay device 7 provided between at least two air conditioning-related devices relays communication by multi-hop. As a result, in the air conditioning-related system, even if the distance between the air conditioning-related devices that need to communicate is long, the air conditioning-related devices can communicate by providing relay device 7 between them and relaying communication.

[0066] Furthermore, the air conditioning-related devices and relay device 7 of the air conditioning-related system according to this embodiment receive signals transmitted by other devices via a transmission line, and when the received signal satisfies a predetermined condition, such as the signal strength not exceeding a threshold, perform a hop (multi-hop) by transmitting the received signal to the transmission line. This makes it possible for the air conditioning-related system to increase the strength of signals whose strength has attenuated according to the transmission distance, which is expected to suppress deterioration of communication quality and to extend the transmission distance of signals related to communication.

[0067] In the air conditioning-related system according to this embodiment, the centralized control device 1, outdoor unit 3, indoor unit 5, relay device 7, and other devices are connected in a daisy chain manner, and it is desirable that the length of the transmission line connecting the two devices is 350 meters or less. As a result of measuring the correspondence between the wiring length and the communication speed (PHY Rate), in an environment with little influence of noise, etc., if the wiring length is 350 meters or less, communication can be performed at a PHY Rate of 55 Mbps.

[0068] In addition, in the air conditioning-related system according to this embodiment, it is desirable that the length of the transmission line connecting the two devices is 200 meters or less. By setting a stricter condition of 200 meters or less than the above-mentioned wiring length of 350 meters or less, it is expected that communication can be performed with a sufficient safety factor S secured in an environment affected by noise, etc.

[0069] <Repeater device placement> Fig. 10 is a schematic diagram for explaining an example of the arrangement of relay devices. In the configuration of the air-conditioning related system shown in Fig. 1 described above, two relay devices 7 are used, and each relay device 7 is provided between two indoor units 5. In contrast, in the configuration of the air-conditioning related system shown in Fig. 10, a relay device 7 is provided between the centralized management device 1 and the outdoor unit 3, and a relay device 7 is provided between the two outdoor units 3. In this way, the relay device 7 according to this embodiment can be connected to any position in the air-conditioning related system to relay communications.

[0070] Since the installation space for the outdoor unit 3 is limited, it is often installed, for example, on the roof of a building. In contrast, if the centralized control device 1 is installed in the basement or first floor of a building, the distance between the centralized control device 1 and the outdoor unit 3 becomes long, and there is a concern that the communication quality may deteriorate due to signal attenuation. Therefore, by connecting a relay device 7 between the centralized control device 1 and the outdoor unit 3, it is expected that the deterioration of the communication quality can be prevented.

[0071] Furthermore, for example, when multiple outdoor units 3 are installed in a property with a large floor area, the distance between the outdoor units 3 may become long depending on the air-conditioned area per outdoor unit 3 or the arrangement of the air-conditioned rooms, and there is concern that signal attenuation may cause a deterioration in communication quality. Therefore, by connecting a relay device 7 between two outdoor units 3, it is expected that the deterioration in communication quality can be prevented.

[0072] Furthermore, for example, in a multi-building property including multiple buildings such as an office building, a school, a hospital, a government office, or a commercial facility, when one centralized control device 1 controls the air conditioning of the multiple buildings, the distance between the outdoor units installed in each building becomes longer by the distance between the buildings, and there is a concern that communication quality may deteriorate due to signal attenuation. Therefore, by connecting a relay device 7 between two outdoor units 3 installed in different buildings, it is expected that the deterioration of communication quality can be prevented. In this case, it is also possible to install multiple relay devices 7 between the two outdoor units 3.

[0073] Also, although not shown in FIG. 10, for example, after the construction of an air conditioning-related system, it may be found that noise from other equipment intrudes into the communication lines, causing a decrease in communication performance or making communication impossible, and it may become necessary to review the wiring. Similarly, for example, when other equipment is added to a building equipped with an air conditioning-related system, this other equipment may become a noise source, making it necessary to review the wiring. In such a case, by placing a relay device 7 on the communication path where noise from other equipment intrudes, the relay device 7 can restore and retransmit the signal, and it is expected that the S / N ratio of other air conditioning-related equipment that receives this signal will be improved. As a result, it is expected that by placing the relay device 7, it will be possible to prevent a decrease in communication quality without having to carry out a major review of the wiring.

[0074] Also, for example, when the wiring length between air conditioning-related devices is long, the system may be configured such that packets sent via multi-hop must always pass through a specific device. In such a system configuration, if a specific device through which packets must pass breaks down, the packets will not be able to reach the devices that follow this specific device. Therefore, by installing relay device 7 near this specific device as a redundant design, when the specific device breaks down, relay device 7 can function as a relay point of multi-hop instead, and it is expected that communication in the air conditioning-related system will be maintained.

[0075] Also, for example, there are cases where it is necessary to cut off the power supply to some devices during maintenance, etc. Cutting off the power supply to some devices may result in the loss of devices that perform multi-hop on the communication path, which may disrupt communication between other devices whose power supply is not cut off. Therefore, by temporarily installing relay device 7 near the device whose power supply is to be cut off, the relay device 7 can take over multi-hop after the power supply is cut off, and it is expected that communication in the air conditioning-related system can be maintained.

[0076] <Modifications of connection configuration> Fig. 11 is a schematic diagram for explaining a connection configuration of air conditioning related devices according to a modified example. In the connection configuration of air conditioning related devices shown in Fig. 7 above, for example, two indoor units 5 are connected via a transmission line 90, and the transmission line 90 is a bundle of three lines, namely, a power line 91, a signal line 92, and a shared line 93. In contrast, in the connection configuration of air conditioning related devices according to a modified example shown in Fig. 11, for example, two indoor units 5 are connected via a transmission line 100, and the transmission line 100 according to the modified example is a bundle of two signal lines 101, 102.

[0077] In the case of the connection configuration of the air-conditioning related devices shown in Fig. 7, power is supplied to each indoor unit 5 via a power line 91. In the connection configuration of the air-conditioning related devices shown in Fig. 11, since the transmission line 100 does not include a power line (not shown), a power line that supplies power from, for example, a commercial power source to each indoor unit 5 is individually connected.

[0078] 11, it is possible to supply power via signal lines 101, 102 included in the transmission line 100, rather than supplying power to each indoor unit 5 individually. By supplying power via the signal lines 101, 102, it is not necessary to secure a power source for each indoor unit 5, and this is expected to improve the ease of use of the air conditioning-related system.

[0079] 11 includes two communication lines 101 and 102, which are non-polarized. Therefore, it is expected that wiring and connection work of the transmission line 100 can be easily performed when implementing an air conditioning-related system.

[0080] In this example, the connection configuration has been described using the indoor unit 5 as an example of the air conditioning-related device, but is not limited to this. For example, a connection configuration using a transmission line 100 including two signal lines 101, 102 may also be adopted for the connection configuration between the centralized control device 1 and the outdoor unit 3, the connection configuration between two outdoor units 3, the connection configuration between the outdoor unit 3 and the indoor unit 5, the connection configuration between the centralized control device 1 and the relay device 7, the connection configuration between the outdoor unit 3 and the relay device 7, the connection configuration between the indoor unit 5 and the relay device 7, and the connection configuration between two relay devices 7.

[0081] <Advantages of adopting HD-PLC for air conditioning related systems> By adopting the HD-PLC communication method in air conditioning-related systems, it is expected that, for example, communication bandwidth and communication speed will be improved. In a system with a slow communication speed, it is difficult to increase the amount of packet data sent between devices, and measures such as fixing the data allocation of packets and sending and receiving only necessary values ​​are necessary. By using high-speed communication with HD-PLC, it is possible to send and receive values ​​sent and received between devices by adding, for example, tag information that indicates the meaning or type information that indicates the type of value. This is expected to improve the flexibility of data sent by the sending device and make it easier for the receiving device to interpret the data, thereby improving the freedom of communication.

[0082] Because it is possible to increase the amount of data in packets sent and received between devices, it becomes possible to apply communication methods with large header sizes, such as IP (Internet Protocol) communication, to air conditioning-related systems. By applying a widely used communication method such as IP communication, it is expected that various communication assets can be reused. For example, it is expected that technologies that improve the reliability of communications, such as TCP (Transmission Control Protocol), or encryption technologies such as TLS (Transport Layer Security) or IPsec (Security Architecture for Internet Protocol), can be applied to air conditioning-related systems.

[0083] By increasing the communication speed, air conditioning-related systems can control, for example, by increasing the communication frequency according to the air conditioning situation, etc. For example, air conditioning-related systems can communicate frequently for defrost control, etc., and can obtain status information and issue operation instructions frequently, which is expected to realize more efficient operation, reduced power consumption, and shorter control completion times.

[0084] In addition, because the status of the equipment can be obtained frequently through communication, if an abnormality occurs in the air conditioning system, for example, a service technician can grasp the status of each device in detail and can grasp the status of multiple devices simultaneously, which is expected to enable quick problem resolution.

[0085] In addition, by adopting the HD-PLC communication method for air conditioning-related systems, the multi-hop function can be used to increase the wiring length and communication distance. As a result, even if a large number of outdoor units 3 and indoor units 5 are installed in a large building, there is no restriction on the total wiring length. Furthermore, by using the relay device 7, there is no restriction on the wiring length between the two devices.

[0086] In addition, because HD-PLC is a communication method that is not dependent on the type of wiring used for communication, it is expected that the air conditioning related system according to this embodiment can be implemented using the wiring of existing air conditioning related systems that use communication methods other than HD-PLC. It is also possible to use the wiring of various systems other than air conditioning related systems.

[0087] In addition, by adopting the HD-PLC communication method for air conditioning-related systems, it is expected that the number of devices that communicate will increase compared to existing air conditioning-related systems. For example, when installing an air conditioning-related system in a large-scale property, the centralized control device 1 needs to control many outdoor units 3 and indoor units 5, but it is expected that the multi-hop function will prevent a decrease in communication quality even if there are many devices connected to the communication line.

[0088] In addition, in air conditioning-related systems, for example, when performing refrigerant control or centralized control, intercommunication occurs between multiple devices, so a network structure is required that allows access to the necessary data from any device. The HD-PLC communication method can be linked with IP communication, and it is expected that the above network structure can be applied to air conditioning-related systems by using IP communication.

[0089] In addition, by adopting the HD-PLC communication method in air conditioning-related systems, it is expected that the resistance to communication anomalies will be improved. The HD-PLC communication method uses OFDM modulation, which performs multi-carrier communication over a wide frequency band. For this reason, even if noise of a certain frequency is mixed in, the air conditioning-related system is expected to maintain communication in other frequency bands. The outdoor unit 3 and indoor unit 5 included in the air conditioning-related system are equipped with mechanisms that can be noise sources, such as switching power supplies or inverters that drive compressors or fans, but it is expected that the effects of these noises will be reduced.

[0090] In addition, because the HD-PLC communication method uses the MHz band as the communication frequency, even if a short circuit occurs in the communication line, it is expected that communication will be maintained without being affected by the short circuit or by reducing the influence due to the impedance of the communication line. This means that it is expected that communication will be maintained even if a short circuit occurs due to a work error during the installation of an air conditioning system or a small animal chewing on the communication line.

[0091] <Connection terminal configuration> Fig. 12 is a block diagram showing another configuration of the relay device. In the configuration of the relay device 7 shown in Fig. 6 above, the relay device 7 has two connection terminals 72, 73, and two devices such as the indoor unit 5 are individually connected to the connection terminals 72, 72 of the relay device 7 via transmission lines. In contrast, the relay device 107 according to the modified example shown in Fig. 12 has one connection terminal 172. The two devices such as the indoor unit 5 are commonly connected to the single connection terminal 172 via a transmission line.

[0092] 7, the connection terminal 172 may be configured such that, for example, three metal terminals are exposed to the outside of the relay device 107. One end of the transmission line is connected to the indoor unit 5 or the like, and the other end is exposed so that the three internal wires are separated, and the three electric wires are fixed to the three metal terminals, respectively. The electric wires and the metal terminals may be fixed by a method such as screwing or soldering, but any method may be used.

[0093] In addition, when the transmission line connected to the connection terminal 172 includes two wires as shown in FIG. 11, the connection terminal 172 can be configured such that, for example, two metal terminals are exposed to the outside of the relay device 107.

[0094] In addition, in this example, two transmission lines are commonly connected to one connection terminal 172, but this is not limiting, and three or more transmission lines may be commonly connected to one connection terminal 172. In this example, the configuration of the connection terminal 172 for the relay device 107 has been described, but this is not limiting, and a similar configuration may be adopted for the connection terminals of the centralized control device 1, the outdoor unit 3, and the indoor unit 5.

[0095] <Power supply> Fig. 13 is a schematic diagram for explaining an example of power supply for a relay device 7. A transmission line 100 bundling two signal lines 101 and 102 is connected to the relay device 7 shown in Fig. 13. The relay device 7 includes a communication unit 71 and a power supply unit 81 connected to the signal lines 101 and 102 of the transmission line 100, respectively.

[0096] The power supply unit 81 obtains power provided from another device via the transmission line 100, converts the power into a DC voltage suitable for various electric circuits such as the communication unit 71 included in the relay device 7, and supplies the power. When the power provided via the transmission line 100 is AC, the power supply unit 81 may have a function of converting the AC power into DC power. The power supply unit 81 may be configured using a circuit such as a DC / DC converter or an AC / DC converter, or an IC, for example.

[0097] The communication unit 71 operates by receiving DC power supplied from the power supply unit 81. The communication unit 71 receives and transmits signals on the transmission line 100, i.e., performs multi-hop communication, thereby relaying communication between at least two devices connected via the transmission line 100. The communication unit 71 also includes a filter circuit that separates the power transmitted via the transmission line 100 from the communication signal.

[0098] Although not shown, when a transmission line 90 bundling three electric wires, a power line 91, a signal line 92, and a shared line 93, is used and power can be exchanged via the power line 91, the power supply unit 81 is connected to the power line 91 and the shared line 93, and the communication unit 71 is connected to the signal line 92 and the shared line 93. The power supply unit 81 obtains power provided via the power line 91 and supplies power to the communication unit 71 and the like.

[0099] Fig. 14 is a schematic diagram for explaining another example of power supply to the relay device 7. A transmission line 100 bundling two electric wires, a signal line 101 and a shared line 102, is connected to the relay device 7 shown in Fig. 14. Note that in this example, power is not supplied via the signal line 101. The relay device 7 includes a communication unit 71 connected to the signal line 101 and the shared line 102 of the transmission line 100, and a power supply unit 82 that obtains power from the outside and supplies it to the communication unit 71 etc.

[0100] The power supply unit 82 is connected to a power source 110 provided outside the relay device 7 via a power supply line such as a power cord. The power source 110 is, for example, a commercial AC power source, and the power supply unit 82 converts AC power from the power source 110 into DC power and supplies the converted DC power to the communication unit 71 and the like.

[0101] In this example, the configuration for power supply to the relay device 7 has been described, but the present invention is not limited to this, and a similar configuration may be adopted for power supply to the centralized control device 1, the outdoor unit 3, and the indoor unit 5.

[0102] <Combined use of low frequency communication> Fig. 15 is a block diagram showing another configuration of relay device 7. Relay device 7 shown in Fig. 15 includes a (first) communication unit 71 that performs communication by the HD-PLC communication method having an OFDM modulation function and a multi-hop function, and a second communication unit 74 that performs communication using a signal with a lower frequency than that of communication unit 71.

[0103] Both the communication unit 71 and the second communication unit 75 are connected to a signal line included in a transmission line connecting the relay device 7 to other devices such as the indoor unit 5. The communication unit 71 communicates with this signal line using a frequency band of, for example, 2 to 28 MHz. On the other hand, the second communication unit 74 communicates using a frequency band of, for example, less than 2 MHz. Note that the communication unit 71 and the second communication unit 74 may each include a filter circuit or the like for separating signals of the frequency band used for communication by the communication unit 71 and the second communication unit 74 from the signal line.

[0104] Although not shown in the figures, each device included in the air conditioning-related system, such as the centralized control device 1, the outdoor unit 3, and the indoor unit 5, also includes a second communication unit 74 that performs low-frequency communication. When performing high-frequency communication using the HD-PLC communication method, these multiple devices included in the air conditioning-related system share identification information, such as a network ID, to identify the network to which they belong. Each device uses the low-frequency communication of the second communication unit 74 when sending and receiving this identification information.

[0105] Any one of the devices included in the air conditioning-related system, for example the centralized control device 1, becomes the master of communication and generates identification information. A device, such as the outdoor unit 3, the indoor unit 5, or the relay device 7, newly connected to the communication network of the air conditioning-related system first performs low-frequency communication with the master centralized control device 1 via the second communication unit 74, acquires the identification information generated by the master via the low-frequency communication, and stores the acquired identification information in a storage unit or the like. The device that has acquired the identification information transmits data including the identification information in, for example, a header, via high-frequency communication using the HD-PLC communication method of the communication unit 71. The device that receives this data extracts the identification information included in the header of the data, and compares the extracted identification information with the identification information stored in itself, thereby determining whether the data can be transmitted or received on the network to which it belongs.

[0106] In high-frequency communication using the HD-PLC communication method, for example, when transmission lines of different networks run parallel or close to each other, crosstalk can cause signals to leak from one transmission line to the other, resulting in crosstalk. If such signal leakage occurs when transmitting and receiving identification information such as a network ID via high-frequency communication, and an air-conditioning-related system device obtains identification information that is different from the correct identification information, this device will not be able to communicate further, and the air-conditioning-related system communication network cannot be constructed correctly.

[0107] The communication by the second communication unit 74 is performed using a low-frequency signal, and there is a low possibility of signal leakage due to crosstalk. By transmitting and receiving the network identification information using low-frequency communication, it is expected that the identification information can be reliably transmitted and received to and from a device or the like newly added to the network.

[0108] Although the embodiments have been described above, it will be understood that various changes in form and details are possible without departing from the spirit and scope of the claims. [Explanation of symbols]

[0109] 1 Centralized management device 3 Outdoor unit 5 Indoor unit 7. Relay Equipment 11 Control section 12 Storage section 13. Communications Department 14 Display section 15 Control section 16 Connection terminal 31 Control Unit 32 Storage section 33 Communications Department 34~36 Connection terminals 51 Control section 52 Storage section 53 Communications Department 54,55 Connection terminal 71 Communications Department 72,73 Connection terminal 74 2nd Communications Department 81 Power supply section 90 Transmission Line 91 Power line 92 Signal Line 93 Shared line 100 Transmission Line 101 Signal line 102 Shared line 107 Relay Equipment 110 Power supply 172 Connection terminal

Claims

1. The relay unit is provided between a first air conditioning related device and a second air conditioning related device that perform multi-hop communication via a transmission line, and relays the communication by multi-hop. a connection terminal to which a transmission line connected to the first air conditioning-related device and a transmission line connected to the second air conditioning-related device are both connected; a first communication unit that performs multi-hop communication via the transmission line; a second communication unit that performs low-frequency communication from the first communication unit via the transmission line; Equipped with Relay equipment.

2. a power supply unit that supplies power to a communication unit that performs processing related to multi-hop communication based on the power supplied through the transmission line; The relay device according to claim 1 .

3. a power supply unit that supplies power to a communication unit that performs processing related to multi-hop communication based on power supplied from a power source external to the device via a power supply line; The relay device according to claim 1 .

4. the second communication unit performs communication for acquiring, from another device, identification information necessary for multi-hop communication by the first communication unit; The relay device according to claim 1 .

5. a first air conditioning related device and a second air conditioning related device that perform multi-hop communication via a transmission line; a relay device connected to the transmission line and provided between the first air conditioning related device and the second air conditioning related device, the relay device relaying the communication by multi-hop; Equipped with the relay device has a connection terminal to which a transmission line connected to the first air conditioning-related device and a transmission line connected to the second air conditioning-related device are both connected, The first air conditioning-related device, the second air conditioning-related device, and the relay device are a first communication unit that performs multi-hop communication via the transmission line; a second communication unit that performs low-frequency communication from the first communication unit via the transmission line; having Air conditioning related systems.

6. A first air conditioning related device and a second air conditioning related device connected to a transmission line perform multi-hop communication via the transmission line, a relay device connected to the transmission line and provided between the first air conditioning-related device and the second air conditioning-related device relays the communication by multi-hop; the relay device includes a connection terminal to which a transmission line connected to the first air conditioning-related device and a transmission line connected to the second air conditioning-related device are both connected, the first air conditioning-related device, the second air conditioning-related device, and the relay device perform a multi-hop first communication and a second communication having a lower frequency than the first communication via the transmission line; Communication methods.

7. The first air conditioning-related device, the second air conditioning-related device, and the relay device are receiving a signal transmitted by another device via the transmission line; transmitting a received signal to the transmission line if the received signal satisfies a predetermined condition; The communication method according to claim 6.

8. the transmission line includes at least two signal lines; The first air conditioning related device, the second air conditioning related device, and the relay device perform communication in accordance with a communication standard for power line communication via the signal line. The communication method according to claim 6.

9. The transmission lines include at least three lines: a power line, a shared line, and a signal line; The first air conditioning related device, the second air conditioning related device, and the relay device perform communication in accordance with a communication standard for power line communication via the signal line. The communication method according to claim 6.

10. The length of a transmission line connecting the first air conditioning-related device and the relay device, and the length of a transmission line connecting the second air conditioning-related device and the relay device are 350 meters or less. The communication method according to claim 6.

11. The length of a transmission line connecting the first air conditioning-related device and the relay device, and the length of a transmission line connecting the second air conditioning-related device and the relay device are 200 meters or less. The communication method according to claim 10.

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