Patent Description:
In the related art, there are known network systems for performing information transmission between devices, examples of which include, as described in PTL <NUM> (<CIT>), a network system for performing information transmission between a plurality of air-conditioning indoor units and a plurality of air-conditioning outdoor units. In such a network system, a plurality of devices such as a plurality of air-conditioning indoor units and a plurality of air-conditioning outdoor units are connected by physical lines, and information is transmitted via a communication signal carried over the physical lines.

In a network in which a plurality of devices are connected by a communication line, the plurality of devices may be divided into a plurality of layers, for example, a first layer and a second layer, with an intermediary device therebetween, the intermediary device being disposed in the middle of the network. In such a network, in some cases, it is desired to perform overall communication using a common line without distinguishing between devices belonging to the first layer and devices belonging to the second layer. In such a network, furthermore, in some cases, it is desired to perform communication among only devices belonging to the first layer using the line described above. In such a network, furthermore, in some cases, it is desired to perform communication among only devices belonging to the second layer using the line described above. <CIT> discloses a network bridge controller for connecting a wind turbine to a utility grid.

In such a network system, however, if the same communication line is used, a signal transmitted from a device belonging to the first layer may be received by a device belonging to the second layer, and communication desired to be performed among devices belonging to the first layer may not be successful. Likewise, if the same communication line is used, a signal transmitted from a device belonging to the second layer may be received by a device belonging to the first layer, and communication desired to be performed among devices belonging to the second layer may not be successful.

Accordingly, it is conceivable that the communication line is separated by an intermediary device and the intermediary device has a function of transferring a communication signal. If the intermediary device has a function of transferring a communication signal, however, in a case where it is desired to perform overall communication without distinguishing between devices belonging to the first layer and devices belonging to the second layer, a failure in the intermediary device may cause a failure in communication between devices belonging to different layers.

It is an object to improve the reliability of communication in a network in which a plurality of devices are classified into a plurality of layers, in a case where communication independent of the layers and communication within the layers are performed through physical lines.

In order to achieve the above objects and effects, the technical solution implemented by the present invention is defined in the independent claim <NUM>. Other features are defined in the dependent claims.

A network system according to a first aspect includes a first-layer device forming part of a first network part, a first line, a second-layer device forming part of a second network part connected to the first network part, a second line, and a first intermediary device. The first line is connected to the first-layer device. The second line is connected to the second-layer device. The first intermediary device includes a first filter always connected to the first line and the second line, and is configured to communicate with the first-layer device and the second-layer device. The first filter is installed so as not to attenuate a high-frequency first signal used for communication among the first-layer device, the first intermediary device, and the second-layer device and so as to attenuate a low-frequency second signal used for communication between the first intermediary device and the second-layer device, other than the first-layer device.

In the network system according to the first aspect, since the first line and the second line can always be connected by the first filter, even if a failure has occurred in the first intermediary device, a state can be maintained in which communication is possible between the first-layer device and the second-layer device. As a result, the network system can improve the reliability of communication.

A network system according to a second aspect is the system according to the first aspect, in which the second-layer device is a plurality of indoor units that air-condition an inside of a room.

In the network system according to the second aspect, even if a failure has occurred in the first intermediary device, a state can be maintained in which communication with the plurality of indoor units is possible, and it is possible to prevent a failure caused due to, for example, the plurality of indoor units being no longer controllable.

A network system according to a third aspect is the system according to the first aspect or the second aspect, further including a third-layer device forming part of a third network part connected to the first network part and the second network part, a third line, and a second intermediary device. The third line is connected to the third-layer device. The second intermediary device includes a second filter always connected to the second line and the third line, and is configured to communicate with the first intermediary device and the third-layer device. The second filter is installed so as not to attenuate the high-frequency first signal used for communication among the first-layer device, the first intermediary device, the second-layer device, the second intermediary device, and the third-layer device and so as to attenuate a low-frequency third signal used for communication between the second intermediary device and the third-layer device, other than the first-layer device, the first intermediary device, and the second-layer device.

In the network system according to the third aspect, since the second line and the third line can always be connected by the second filter, even if a failure has occurred in the second intermediary device, a state can be maintained in which communication is possible between the second-layer device and the third-layer device.

A network system according to a fourth aspect is the system according to the third aspect, in which the first-layer device is an outdoor unit or a centralized controller capable of controlling the second-layer device and the third-layer device.

In the network system according to the fourth aspect, even if a failure has occurred in the first intermediary device and/or the second intermediary device, a state can be maintained in which the outdoor unit or the centralized controller can communicate with the plurality of indoor units. In the network system according to the fourth aspect, it is possible to prevent a failure caused by, for example, the outdoor unit or the centralized controller being no longer able to control the plurality of indoor units.

A network system according to a fifth aspect is the system according to any one of the first to fourth aspects, in which the first intermediary device recognizes the second-layer device using the second signal. The first-layer device recognizes the second-layer device via communication with the first intermediary device.

In the network system according to the fifth aspect, the first-layer device can recognize the second-layer device connected to the first intermediary device by the second line through the first intermediary device. For example, even if another device is connected between the first-layer device and the first intermediary device, the first-layer device can recognize and manage the second-layer device in a way distinguishable from the other device.

A network system according to a first embodiment will be described with reference to an air conditioning system <NUM> illustrated in <FIG>. The air conditioning system <NUM> according to the first embodiment includes an outdoor unit <NUM>, one first indoor unit <NUM>, a first intermediary unit <NUM>, a plurality of second indoor units <NUM>, a first line <NUM>, and a second line <NUM>.

The outdoor unit <NUM> and the first indoor unit <NUM> are first-layer devices. The first line <NUM> is a physical wire. The first line <NUM> is connected to the outdoor unit <NUM> and the first indoor unit <NUM>. The plurality of second indoor units <NUM> are second-layer devices. The second line <NUM> is a physical wire. The second line <NUM> is connected to the plurality of second indoor units <NUM>. The first line <NUM> and the second line <NUM> may be each constituted by a plurality of wires extending in parallel.

The first intermediary unit <NUM> includes a first filter <NUM>. The first filter <NUM> is always connected to the first line <NUM> and the second line <NUM>. The first intermediary unit <NUM> is configured to be capable of communicating with the outdoor unit <NUM>, which is a first-layer device, via a second signal. The first intermediary unit <NUM> is a first intermediary device.

The first filter <NUM> does not attenuate a high-frequency first signal, which is used for communication among the outdoor unit <NUM>, the first indoor unit <NUM>, the first intermediary unit <NUM>, and the plurality of second indoor units <NUM>. The first filter <NUM> attenuates a low-frequency second signal, which is used for communication between the first intermediary unit <NUM> and the plurality of second indoor units <NUM>, other than the outdoor unit <NUM> and the first indoor unit <NUM>. In the present disclosure, high frequencies are defined to be frequencies higher than or equal to <NUM>, and low frequencies are defined to be frequencies lower than or equal to <NUM>. The low frequencies include <NUM> (direct current). The first filter <NUM> is installed so as not to attenuate a high-frequency first signal and so as to attenuate a low-frequency second signal, which indicates that, for example, the first filter <NUM> is installed so that the attenuation factor for the high-frequency first signal is smaller than the attenuation factor for the low-frequency second signal.

The first filter <NUM> is a device that passes high-frequency signals and blocks low-frequency signals. Examples of the filter that passively passes high-frequency signals and blocks low-frequency signals include a capacitor, and an attenuator that attenuates low-frequency signals. The filter used as the first filter <NUM> may be an active filter including an active element. For example, an inductive coupler that passes high-frequency signals and blocks direct-current signals can also be used as the filter <NUM>. There is a switching device that switches connection and disconnection between the first line <NUM> and the second line <NUM>. The switching device is a device that disconnects the first line <NUM> and the second line <NUM> from each other to carry a low-frequency signal over the first line <NUM> and the second line <NUM>. In the switching device, for example, a relay can be used to switch connection and disconnection between the first line <NUM> and the second line <NUM>.

<FIG> exemplarily illustrates a case where one first indoor unit <NUM> is used. However, the air conditioning system <NUM> may be configured to include a plurality of first indoor units <NUM>. Alternatively, the air conditioning system <NUM> may be configured not to include the first indoor unit <NUM>.

In the air conditioning system <NUM> according to the first embodiment, refrigerant circulates among the outdoor unit <NUM>, the first indoor unit <NUM>, the first intermediary unit <NUM>, and the plurality of second indoor units <NUM>. To circulate refrigerant, the air conditioning system <NUM> includes refrigerant pipes <NUM>, <NUM>, <NUM>, <NUM>, and <NUM>. The outdoor unit <NUM> and the first indoor unit <NUM> are connected by the refrigerant pipes <NUM> and <NUM>. The outdoor unit <NUM> and the first intermediary unit <NUM> are connected by the refrigerant pipes <NUM>, <NUM>, and <NUM>. The second indoor units <NUM> and the first intermediary unit <NUM> are connected by the refrigerant pipes <NUM> and <NUM>. In the air conditioning system <NUM>, a vapor compression refrigeration cycle is performed by the circulation of the refrigerant. In the air conditioning system <NUM>, the circulation of the refrigerant causes thermal energy transfer between the outdoor unit <NUM>, and the first indoor unit <NUM> and the plurality of second indoor units <NUM>.

While the internal configuration of the outdoor unit <NUM> is not illustrated, the outdoor unit <NUM> is configured to include, for example, a compressor, a four-way valve, a heat exchanger, an expansion valve, and a fan. The outdoor unit <NUM> is a device that performs heat exchange between outdoor air and the refrigerant. The outdoor unit <NUM> sucks gaseous refrigerant flowing through the refrigerant pipe <NUM> and supplies low-temperature liquid refrigerant flowing through the refrigerant pipe <NUM> and high-temperature gaseous refrigerant flowing through the refrigerant pipe <NUM>.

While the internal configuration of the first indoor unit <NUM> and the second indoor units <NUM> is not illustrated, each of the first indoor unit <NUM> and the second indoor units <NUM> includes, for example, a heat exchanger, an expansion valve, and a fan. The first indoor unit <NUM> and the second indoor units <NUM> are each a device that performs heat exchange between indoor air and the refrigerant. In each of the first indoor unit <NUM> and the second indoor units <NUM>, for example, the heat exchanger exchanges heat between the refrigerant and the indoor air, and the fan blows heat-exchanged air to the outside. The first indoor unit <NUM> and the second indoor units <NUM> perform cooling using low-temperature refrigerant or perform heating using high-temperature refrigerant.

The first intermediary unit <NUM> is a device that adjusts refrigerant to be caused to flow into the plurality of second indoor units <NUM> connected to the first intermediary unit <NUM>, such as switching the flow of the refrigerant to be caused to flow into the plurality of second indoor units <NUM>.

The outdoor unit <NUM> includes an outdoor controller <NUM>. The outdoor controller <NUM> includes a microcontroller unit (MCU) 55a, a transmitter 55b, and a transceiver 55c. The transmitter 55b and the transceiver 55c of the outdoor unit <NUM> are connected to the first line <NUM>.

The first indoor unit <NUM> includes an indoor controller <NUM>. The indoor controller <NUM> includes a microcontroller unit (MCU) 65a, a receiver 65b, and a transceiver 65c. The receiver 65b and the transceiver 65c of the first indoor unit <NUM> are connected to the first line <NUM>.

Each of the second indoor units <NUM> includes an indoor controller <NUM>. The indoor controller <NUM> includes a microcontroller unit (MCU) 65a, a receiver 65b, and a transceiver 65c. The receivers 65b and the transceivers 65c of the second indoor units <NUM> are connected to the second line <NUM>.

The first intermediary unit <NUM> includes an intermediary controller <NUM>. The intermediary controller <NUM> includes a microcontroller unit (MCU) 70a, a receiver 70b, a transceiver 70c, and a transmitter 70d. The receiver 70b and the transceiver 70c of the first intermediary unit <NUM> are connected to the first line <NUM>. The transmitter 70d of the first intermediary unit <NUM> is connected to the second line <NUM>.

The transceivers 55c, 65c, and 70c perform communication via high-frequency first signals. The transmitters 55b and 70d and the receivers 65b and 70b perform communication via low-frequency second signals.

An MCU includes, for example, a control arithmetic unit and a storage device (memory). The control arithmetic unit can be implemented using a processor such as a CPU or a GPU. The control arithmetic unit reads a program stored in the storage device and performs predetermined image processing and arithmetic processing in accordance with the program. Further, the control arithmetic unit can write an arithmetic result to the storage device or read information stored in the storage device in accordance with the program.

As described above, the air conditioning system <NUM> circulates refrigerant to perform air conditioning. Before performing the air conditioning operation, the air conditioning system <NUM> recognizes a communication target in accordance with the circulation of the refrigerant. The recognition of the communication target in accordance with the circulation of the refrigerant is system recognition. Communication of the air conditioning system <NUM> for performing system recognition will be described with reference to <FIG>.

First, to perform communication for system recognition, the power source for the air conditioning system <NUM> is turned on (step ST1). The outdoor controller <NUM>, the plurality of indoor controllers <NUM>, and the intermediary controller <NUM>, which are connected to the first line <NUM> and the second line <NUM>, establish a network (step ST2). For example, the outdoor controller <NUM> uses the transceiver 55c to transmit and receive communication signals to and from the transceivers 65c of the plurality of indoor controllers <NUM> and the transceiver 70c of the intermediary controller <NUM> to establish a network.

After the network is established, the outdoor unit <NUM>, the first indoor unit <NUM>, the plurality of second indoor units <NUM>, and the first intermediary unit <NUM> each acquire a communication address (step ST3). The MCU 55a of the outdoor controller <NUM>, the MCUs 65a of the plurality of indoor controllers <NUM>, and the MCU 70a of the intermediary controller <NUM> have a function of, for example, automatically acquiring a communication address. Using this function, the outdoor unit <NUM>, the first indoor unit <NUM>, the plurality of second indoor units <NUM>, and the first intermediary unit <NUM> can acquire communication addresses that do not overlap each other.

The outdoor unit <NUM> and the first intermediary unit <NUM> cooperate with each other via communication using the transceiver 55c and the transceiver 70c and select one recognition device on the network (step ST4). Here, for example, the outdoor unit <NUM> is selected. When the outdoor unit <NUM> is selected, the first intermediary unit <NUM> changes the role from a recognition device to a recognition-target device. Changing the role from a recognition device to a recognition-target device means entering a state in which the receiver 70b is ready to receive a second signal sent from the transmitter 55b of the outdoor unit <NUM>.

The selected recognition device uses the transmitter to transmit a second signal to devices in the layer to which the recognition device belongs for refrigerant system recognition (step ST5). For example, in a case where the outdoor unit <NUM> is selected, the outdoor unit <NUM> uses the transmitter 55b to transmit a second signal to the first line <NUM> for refrigerant system recognition. The second signal transmitted from the transmitter 55b is a low-frequency signal and is thus difficult to pass through the first filter <NUM>. In other words, the second signal is attenuated by the first filter <NUM> and thus is not received as a valid signal at the receivers 65b of the second indoor units <NUM>. In other words, furthermore, due to the attenuation effect of the first filter <NUM>, the second signal transmitted from the transmitter 55b of the outdoor controller <NUM> of the outdoor unit <NUM> is not receivable at the receivers 65b of the second indoor units <NUM>. The outdoor unit <NUM> transmits its communication address via a first signal by using the transceiver 55c simultaneously with the transmission of the second signal or before or after the transmission of the second signal. In this case, the outdoor unit <NUM> may be configured to send the communication address via a low-frequency signal having a frequency other than <NUM>.

The first indoor unit <NUM>, which has received the second signal at the receiver 65b and has received the communication address of the outdoor unit <NUM> at the transceiver 65c or the receiver 65b through the first line <NUM>, stores the received communication address in a memory of the MCU 63a. The first intermediary unit <NUM>, which has received the second signal at the receiver 70b and has received the communication address of the outdoor unit <NUM> at the transceiver 70c or the receiver 70b through the first line <NUM>, stores the received communication address in a memory of the MCU 70a.

A recognition-target device that has received the second signal and the communication address of the recognition device transmits its communication address to the communication address of the recognition device (step ST6). In a case where the outdoor unit <NUM> is selected, the first indoor unit <NUM> and the first intermediary unit <NUM> transmit their communication addresses to the communication address of the outdoor unit <NUM> through the first line <NUM> by using the transceiver 65c and the transceiver 70c.

The selected recognition device registers the sent communication address of the recognition-target device in the same system list in which indoor units in the same layer are registered (step ST7). In a case where the outdoor unit <NUM> is selected, the outdoor unit <NUM> sequentially adds the communication addresses of the first indoor unit <NUM> and the first intermediary unit <NUM>, which are sent to the communication address of the outdoor unit <NUM> through the first line <NUM>, to the same system list. The outdoor unit <NUM> holds the same system list, thereby recognizing that the outdoor unit <NUM> is a first-layer device belonging to the first layer.

The selected recognition device notifies, upon completion of the registration of all the recognition-target devices in the layer to which the recognition device belongs, the entire network that the system recognition for the layer to which the recognition device belongs is completed (step ST8). In a case where the outdoor unit <NUM> is selected, upon completion of the registration of the first indoor unit <NUM> in the first layer and the first intermediary unit <NUM>, the outdoor unit <NUM> notifies the entire network that the system recognition for the first layer is completed, through the first line <NUM> and the second line <NUM> by using the transceiver 55c.

It is determined whether there is a recognition device that has not completed system recognition (step ST9). In a case where the outdoor unit <NUM> is selected, even if the outdoor unit <NUM> has first completed the system recognition, the first intermediary unit <NUM> has not completed the system recognition for the second layer (Yes in step ST9). In such a case, the outdoor unit <NUM> and the first intermediary unit <NUM> cooperate with each other via communication using the transceiver 55c and the transceiver 70c and select the first intermediary unit <NUM> as a recognition device (step ST4).

If the first intermediary unit <NUM> is selected as a recognition device, the first intermediary unit <NUM> changes the role from a recognition-target device to a recognition device. The selected first intermediary unit <NUM> uses the transmitter 70d to transmit a second signal to devices in a layer lower than the layer of the first intermediary unit <NUM> through the second line <NUM> (step ST5). The second signal transmitted from the transmitter 55b is a low-frequency signal and is thus difficult to pass through the first filter <NUM>. In other words, due to the attenuation effect of the first filter <NUM>, the second signal transmitted from the transmitter 70d of the intermediary controller <NUM> of the first intermediary unit <NUM> is not receivable at the receiver 65b of the first indoor unit <NUM>. The first intermediary unit <NUM> uses the transceiver 70c to transmit its communication address via a first signal simultaneously with the transmission of the second signal or before or after the transmission of the second signal. In this case, the first intermediary unit <NUM> may be configured to send the communication address via a low-frequency signal having a frequency other than <NUM>. The plurality of second indoor units <NUM>, which have received the second signal at the receivers 65b and have received the communication address of the first intermediary unit <NUM> at the transceivers 65c or the receivers 65b through the second line <NUM>, store the received communication address in memories of the respective MCUs 63a.

The plurality of second indoor units <NUM>, which have received the second signal and the communication address of the first intermediary unit <NUM>, transmit their communication addresses to the communication address of the first intermediary unit <NUM> (step ST6). The first intermediary unit <NUM> registers the communication addresses of the plurality of second indoor units <NUM>, which are sent through the second line <NUM>, in the same system list in which second-layer devices in the second layer are registered (step ST7).

The first intermediary unit <NUM> notifies, upon completion of the registration of all of the second indoor units <NUM> in the second layer, the entire network that the system recognition for the second layer is completed (step ST8). The first intermediary unit <NUM> notifies the entire network that the system recognition for the second layer is completed through the first line <NUM> and the second line <NUM> by using the transceiver 70c. At this time, the first intermediary unit <NUM> transmits the communication addresses of the second indoor units <NUM> in the second layer to the MCU 55a of the outdoor controller <NUM> of the outdoor unit <NUM> through the first line <NUM> by using the transceiver 70c. The outdoor unit <NUM> registers the communication addresses of the plurality of second indoor units <NUM>, which are received from the first intermediary unit <NUM>, in the same system list as the communication addresses of the second-layer devices.

The determination of whether there is a recognition device that has not completed system recognition (step ST9) is performed after the outdoor unit <NUM> and the first intermediary unit <NUM> have completed the system recognition. Accordingly, since all of the recognition devices illustrated in <FIG>, namely, the outdoor unit <NUM> and the first intermediary unit <NUM>, have completed the system recognition (No in step ST9), the air conditioning system <NUM> terminates the communication for system recognition.

The foregoing description of an example of the communication for system recognition presents a case where a communication destination and/or a communication source is identified using communication addresses in communication performed by the transceivers 55c, 65c, and 70c using communication signals through the first line <NUM> and the second line <NUM>. However, the identification of a communication destination and/or a communication source is not limited to the identification using communication addresses. For example, the air conditioning system <NUM> may be configured to identify a communication destination and/or a communication source using unique IDs of the outdoor unit <NUM>, the first indoor unit <NUM>, the plurality of second indoor units <NUM>, and the first intermediary unit <NUM>.

When the system recognition is completed, the communication address of the first indoor unit <NUM> connected to the first line <NUM> is registered as a first-layer device, and the communication addresses of the second indoor units <NUM> are registered as second-layer devices, and the communication address of the first intermediary unit <NUM> is registered as a first intermediary device in the same system list in the MCU 55a of the outdoor unit <NUM>.

The outdoor unit <NUM> can use the same system list stored in the MCU 55a to identify the first indoor unit <NUM>, the plurality of second indoor units <NUM>, and the first intermediary unit <NUM> belonging to the same refrigerant system and control the vapor compression refrigeration cycle of the refrigerant system. In addition, the outdoor unit <NUM> can use the same system list to send instructions to the first indoor unit <NUM>, which is a first-layer device, the plurality of second indoor units <NUM>, which are second-layer devices, and the first intermediary unit <NUM>, which is a first intermediary device, in a distinguishable manner using communication signals through the first line <NUM> and the second line <NUM>.

For example, if the discharge temperature of the compressor of the outdoor unit <NUM> becomes abnormally high, the outdoor unit <NUM> can use the transceiver 55c to instruct the first indoor unit <NUM>, the plurality of second indoor units <NUM>, and the first intermediary unit <NUM>, which are registered in the same system list, to address the abnormal discharge temperature of the compressor using communication signals through the first line <NUM> and the second line <NUM>.

For example, the outdoor unit <NUM> can use the transceiver 55c to instruct only the first indoor unit <NUM>, which is a first-layer device registered in the same system list, to change the air conditioning capacity using a communication signal through the first line <NUM>. The outdoor unit <NUM> can further use the transceiver 55c to instruct the plurality of second indoor units <NUM>, which are second-layer devices, and the first intermediary unit <NUM>, which are registered in the same system list, to change the air conditioning capacity using communication signals through the first line <NUM> and the second line <NUM>.

The first embodiment described above presents a case where the outdoor unit <NUM> and the first indoor unit <NUM> are first-layer devices, the first intermediary unit <NUM> is a first intermediary device, and the plurality of second indoor units <NUM> are second-layer devices. However, a first-layer device, a second-layer device, and a first intermediary device are not limited to those in the first embodiment. For example, an air conditioning system <NUM> according to a second embodiment illustrated in <FIG> may be used.

The air conditioning system <NUM> according to the second embodiment includes a centralized controller <NUM>, an outdoor unit <NUM>, a plurality of outdoor units <NUM>, a plurality of third indoor units <NUM>, a first line <NUM>, and a second line <NUM>. In the air conditioning system <NUM> according to the second embodiment, the centralized controller <NUM> is a first-layer device, the outdoor unit <NUM> is a first intermediary device, and the plurality of outdoor units <NUM> are second-layer devices. The first line <NUM> and the second line <NUM> are physical wires. The first line <NUM> is connected to the centralized controller <NUM> and the outdoor unit <NUM>. The second line <NUM> is connected to the plurality of outdoor units <NUM> and the plurality of third indoor units <NUM>.

The outdoor unit <NUM> includes a first filter <NUM>. The first filter <NUM> is always connected to the first line <NUM> and the second line <NUM>. The outdoor unit <NUM> communicates with the centralized controller <NUM>, which is a first-layer device, and also communicates with the plurality of outdoor units <NUM> and the plurality of third indoor units <NUM>, which are second-layer devices. The relationship between a first signal and a second signal, which are used for communication in the air conditioning system <NUM>, and the relationship between these signals and the first filter <NUM> are similar to those in the first embodiment.

In the air conditioning system <NUM> according to the second embodiment, refrigerant circulates among the outdoor unit <NUM>, the plurality of outdoor units <NUM>, and the plurality of third indoor units <NUM>. In the air conditioning system <NUM>, a vapor compression refrigeration cycle is performed by such circulation of the refrigerant. In the air conditioning system <NUM>, the circulation of the refrigerant causes thermal energy transfer between the outdoor units <NUM> and <NUM> and the third indoor units <NUM>. Each of the third indoor units <NUM> includes a heat exchanger (not illustrated). In each of the third indoor units <NUM>, the heat exchanger exchanges heat between the refrigerant and indoor air to perform at least one of cooling, heating, and dehumidification of the indoor space.

The centralized controller <NUM> includes a microcontroller unit (MCU) 10a, a transmitter 10b, and a transceiver 10c. The transmitter 10b and the transceiver 10c of the centralized controller <NUM> are connected to the first line <NUM>.

The outdoor unit <NUM> includes an outdoor controller <NUM>. The outdoor controller <NUM> includes a microcontroller unit (MCU) 56a, a receiver 56b, a transceiver 56c, and a transmitter 56d. The receiver 56b and the transceiver 56c of the outdoor unit <NUM> are connected to the first line <NUM>. The transmitter 56d of the outdoor unit <NUM> is connected to the second line <NUM>.

Each of the outdoor units <NUM> includes an outdoor controller <NUM>. The outdoor controller <NUM> includes a microcontroller unit (MCU) 57a, a receiver 57b, and a transceiver 57c. The receivers 57b and the transceivers 57c of the outdoor units <NUM> are connected to the second line <NUM>.

Each of the third indoor units <NUM> includes an indoor controller <NUM>. The indoor controller <NUM> includes a microcontroller unit (MCU) 65a, a receiver 65b, and a transceiver 65c. The receivers 65b and the transceivers 65c of the third indoor units <NUM> are connected to the second line <NUM>.

The transceivers 10c, 56c, 57c, and 65c perform communication via high-frequency first signals. The transmitter 10b and the receiver 56b perform communication via low-frequency second signals, and the transmitter 56d and the receivers 57b and 65b perform communication via low-frequency second signals.

Communication for system recognition according to the second embodiment can be performed by an operation similar to the operation of communication for system recognition according to the first embodiment. In the air conditioning system <NUM> according to the second embodiment, the operation of the transmitter 55b and the transceiver 55c of the outdoor controller <NUM> according to the first embodiment is performed by the transmitter 10b and the transceiver 10c of the centralized controller <NUM> according to the second embodiment. The operation of the receiver 70b, the transceiver 70c, and the transmitter 70d of the intermediary controller <NUM> according to the first embodiment is performed by the receiver 56b, the transceiver 56c, and the transmitter 56d of the outdoor controller <NUM> according to the second embodiment. The operation of the receivers 65b and the transceivers 65c of the indoor controllers <NUM> of the second indoor units <NUM> according to the first embodiment is performed by the receivers 57b and the transceivers 57c of the outdoor controllers <NUM> and the receivers 65b and the transceivers 65c of the indoor controllers <NUM> according to the second embodiment. Also in the air conditioning system <NUM> according to the second embodiment, the communication for system recognition can be performed in accordance with the flowchart illustrated in <FIG>.

In the air conditioning system <NUM> according to the second embodiment, the centralized controller <NUM> is a recognition device, and the outdoor unit <NUM> is a device having two aspects, namely, a recognition device and a recognition-target device. In the second embodiment, the plurality of outdoor units <NUM> and the plurality of third indoor units <NUM> are recognition-target devices. In the second embodiment, the centralized controller <NUM> performs system recognition to recognize devices belonging to a refrigerant system <NUM>. Although there is no first-layer device to be registered in the same system list in the centralized controller <NUM>, the centralized controller <NUM> holds the same system list, thereby recognizing that the centralized controller <NUM> is a first-layer device belonging to the first layer. The centralized controller <NUM> may be configured to notify the outdoor units <NUM> and <NUM> of devices belonging to the refrigerant system <NUM> recognized by the centralized controller <NUM>.

The first embodiment and the second embodiment described above present a case where the air conditioning system <NUM> includes two layers including the first-layer device(s) and the second-layer devices. However, an air conditioning system according to the present disclosure may not necessarily include two layers, and may include three or more layers. In the third embodiment described above, as illustrated in <FIG>, a second intermediary unit <NUM>, which is a second intermediary device, and fourth indoor units <NUM>, which are third-layer devices, are installed in positions lower than the third indoor units <NUM>, which are second-layer devices according to the second embodiment.

An air conditioning system <NUM> according to the third embodiment is the same as the air conditioning system <NUM> according to the second embodiment in that the air conditioning system <NUM> according to the third embodiment includes the centralized controller <NUM> to the third indoor units <NUM>, namely, a first-layer device, a first intermediary device, and second-layer devices. In the air conditioning system <NUM> according to the third embodiment, the fourth indoor units <NUM>, which are third-layer devices, the second intermediary unit <NUM>, which is a second intermediary device, and a physical third line <NUM> are added to the air conditioning system <NUM> according to the second embodiment.

In the air conditioning system <NUM> according to the third embodiment, the third line <NUM> is connected to the plurality of fourth indoor units <NUM>.

The second intermediary unit <NUM> includes a second filter <NUM>. The second filter <NUM> is always connected to the second line <NUM> and the third line <NUM>. The second intermediary unit <NUM> communicates with the centralized controller <NUM>, which is a first-layer device, and also communicates with the outdoor unit <NUM>, which is a first intermediary device, and the plurality of outdoor units <NUM> and the plurality of third indoor units <NUM>, which are second-layer devices. The relationship between a first signal and a second signal, which are used for communication in the air conditioning system <NUM>, and the relationship between these signals and the second filter <NUM> are similar to the relationship between the first signal and the second signal according to the second embodiment and the relationship between these signals and the first filter <NUM>. The second filter <NUM> does not attenuate a high-frequency first signal, and attenuates a low-frequency second signal. The second filter <NUM> is installed so as not to attenuate a high-frequency first signal and so as to attenuate a low-frequency second signal, which indicates that, for example, the second filter <NUM> is installed so that the attenuation factor for the high-frequency first signal is smaller than the attenuation factor for the low-frequency second signal. The second intermediary unit <NUM> is configured to be capable of communicating with the first intermediary unit <NUM>, which is a first intermediary device, via a second signal.

Like the first filter <NUM>, the second filter <NUM> can include, for example, a capacitor, an attenuator that attenuates low-frequency signals, an active filter, and a switching device that disconnects the second line <NUM> and the third line <NUM> from each other to carry a low-frequency signal over the second line <NUM> and the third line <NUM>. The switching device can be implemented using, for example, a relay.

In the air conditioning system <NUM> according to the third embodiment, refrigerant circulates among the outdoor unit <NUM>, the plurality of outdoor units <NUM>, the plurality of third indoor units <NUM>, the second intermediary unit <NUM>, and the fourth indoor units <NUM>. In the air conditioning system <NUM>, a vapor compression refrigeration cycle is performed by such circulation of the refrigerant. In the air conditioning system <NUM>, the circulation of the refrigerant causes thermal energy transfer between the outdoor units <NUM> and <NUM>, the third indoor units <NUM>, the second intermediary unit, and the fourth indoor units <NUM>. The third indoor units <NUM> and the fourth indoor units <NUM> each includes a heat exchanger (not illustrated). In each of the third indoor units <NUM> and the fourth indoor units <NUM>, the heat exchanger exchanges heat between the refrigerant and indoor air to perform at least one of cooling, heating, and dehumidification of the indoor space.

The centralized controller <NUM>, the outdoor controller <NUM> of the outdoor unit <NUM>, the outdoor controllers <NUM> of the outdoor units <NUM>, and the indoor controllers <NUM> of the third indoor units <NUM> have been described in the second embodiment, and the description thereof is thus omitted here. Further, the intermediary controller <NUM> included in the second intermediary unit <NUM> has the same configuration as that of the intermediary controller <NUM> of the first intermediary unit <NUM>, and the description thereof is thus omitted here. The transceivers 10c, 56c, 57c, 65c, and 70c perform communication via high-frequency first signals. The transmitter 10b and the receiver 56b perform communication via low-frequency second signals, the transmitter 56d and the receivers 57b and 65b perform communication via low-frequency second signals, and the transmitter 70d and the receivers 65b perform communication via low-frequency second signals.

In communication for system recognition according to the third embodiment, the recognition of a first-layer device by the centralized controller <NUM> and the recognition of a second-layer device by the outdoor unit <NUM> can be performed in a way similar to that in the communication for system recognition according to the second embodiment described above. In the communication for system recognition according to the third embodiment, the recognition of a third-layer device by the second intermediary unit <NUM> can be performed by an operation similar to that in the recognition of a second-layer device by the first intermediary unit <NUM> according to the second embodiment.

In step ST9 in <FIG> for determining whether there is a recognition device that has not completed system recognition, it is assumed that the centralized controller <NUM> and the outdoor unit <NUM> have completed system recognition and the second intermediary unit <NUM> has not completed system recognition. In this case (Yes in step ST9), the centralized controller <NUM>, the outdoor unit <NUM>, and the second intermediary unit <NUM> cooperate with each other via communication using the transceivers 10c, 55c, and 70c and select the second intermediary unit <NUM> as a recognition device (step ST4).

When the second intermediary unit <NUM> is selected as a recognition device, the second intermediary unit <NUM> changes the role from a recognition-target device to a recognition device. The selected second intermediary unit <NUM> uses the transmitter 70d to transmit a second signal to devices in a layer lower than the layer of the second intermediary unit <NUM> through the third line <NUM> (step ST5). Due to the attenuation effect of the second filter <NUM>, the receivers 65b of the third indoor units <NUM> are not allowed to receive the second signal transmitted from the transmitter 70d of the intermediary controller <NUM> of the second intermediary unit <NUM>. The second intermediary unit <NUM> transmits its communication address via a first signal by using the transceiver 70c simultaneously with the transmission of the second signal or before or after the transmission of the second signal. In this case, the second intermediary unit <NUM> may be configured to send the communication address via a low-frequency signal having a frequency other than <NUM>. The plurality of fourth indoor units <NUM>, which have received the second signal at the receivers 65b through the third line <NUM> and have received the communication address of the second intermediary unit <NUM> at the transceivers 65c or the receivers 65b, store the received communication address in memories of the respective MCUs 63a.

The plurality of fourth indoor units <NUM>, which have received the second signal and the communication address of the second intermediary unit <NUM>, transmit their communication addresses to the communication address of the second intermediary unit <NUM> (step ST6). The second intermediary unit <NUM> registers the communication addresses of the plurality of fourth indoor units <NUM>, which are sent through the third line <NUM>, in the same system list in which second-layer devices in the second layer are registered (step ST7).

The second intermediary unit <NUM> notifies, upon completion of the registration of all of the fourth indoor units <NUM> in the second layer, the entire network that the system recognition for the second layer is completed (step ST8). The second intermediary unit <NUM> notifies the entire network that the system recognition for the second layer is completed through the first line <NUM>, the second line <NUM>, and the third line <NUM> by using the transceiver 70c. At this time, the second intermediary unit <NUM> transmits the communication addresses of the fourth indoor units <NUM> in the second layer to the MCU 56a of the outdoor controller <NUM> of the outdoor unit <NUM> through the second line <NUM> by using the transceiver 70c. The outdoor unit <NUM> registers the communication addresses of the plurality of fourth indoor units <NUM>, which are received from the second intermediary unit <NUM>, in the same system list as the communication addresses of third-layer devices. The MCU 56a of the outdoor controller <NUM> of the outdoor unit <NUM> transmits the communication addresses of the fourth indoor units <NUM> in the second layer to the MCU 10a of the centralized controller <NUM> through the first line <NUM> by using the transceiver 56c. The centralized controller <NUM> registers the communication addresses of the plurality of fourth indoor units <NUM>, which are received from the outdoor unit <NUM>, in the same system list as the communication addresses of third-layer devices.

In the air conditioning system <NUM> according to the third embodiment, the centralized controller <NUM> is a recognition device, and the outdoor unit <NUM> and the second intermediary unit <NUM> are devices having two aspects, namely, a recognition device and a recognition-target device. In the third embodiment, the plurality of outdoor units <NUM>, the plurality of third indoor units <NUM>, and the plurality of fourth indoor units <NUM> are recognition-target devices.

In the first embodiment, the second embodiment, and the third embodiment described above, the air conditioning system <NUM> has been described as a network system, by way of example. However, the network system is not limited to an air conditioning system. Examples of the network system to which the technology of the present disclosure is applicable include a hot-water supply system and a ventilation system.

In the first embodiment, the second embodiment, and the third embodiment described above, a case has been described in which a first intermediary device and second-layer devices are provided only in one row. Alternatively, a first intermediary device and second-layer devices can be configured to be provided in a plurality of rows in parallel. For example, as in an air conditioning system <NUM> illustrated in <FIG>, a first intermediary device and second-layer devices may be configured to be provided in a plurality of rows in parallel. In the air conditioning system <NUM> in <FIG>, two first intermediary units <NUM>, which are first intermediary devices, are connected to the first line <NUM>. Each of the first intermediary units <NUM> is connected to three second indoor units <NUM> by the second line <NUM>.

In the first embodiment, the second embodiment, and the third embodiment described above, a case has been described in which the first intermediary device is the first intermediary unit <NUM> or the outdoor unit <NUM>. However, the first intermediary device is not limited to such devices. For example, the first intermediary device may be implemented using a power supply unit that supplies a direct-current voltage or an alternating-current voltage to indoor units.

In the first embodiment, the second embodiment, and the third embodiment described above, a case has been described in which the first intermediary unit <NUM> and/or the outdoor units <NUM> and <NUM> include the transmitters 55b, 56d, and 70d that transmit low-frequency signals. However, in some cases, a device for performing recognition is not determined before the air conditioning system <NUM> is constructed. For example, as illustrated in <FIG>, after a plurality of outdoor units <NUM> are connected, an outdoor unit <NUM> on the side that performs recognition and an outdoor unit <NUM> on the side that is recognized may be determined. To address this case, each of the plurality of outdoor units <NUM> can be configured to include a low-frequency transceiver 56e, in place of a low-frequency transmitter, for system recognition (see <FIG>). In the air conditioning system <NUM>, an intermediary device, such as the first intermediary unit <NUM>, can also be configured to include a low-frequency transceiver for system recognition.

In the second embodiment and the third embodiment described above, a case has been described in which the centralized controller <NUM> includes the transmitter 10b that transmits a low-frequency signal. However, in some cases, a device for performing recognition is not determined before the air conditioning system <NUM> is constructed. For example, as illustrated in <FIG>, after a plurality of centralized controllers <NUM> are connected, a centralized controller <NUM> on the side that performs recognition and a centralized controller <NUM> on the side that is recognized may be determined. To address this case, each of the plurality of centralized controllers <NUM> can be configured to include a low-frequency transceiver 10e, in place of a low-frequency transmitter, for system recognition (see <FIG>).

In the third embodiment described above, a case has been described in which a second intermediary device and third-layer devices are provided only in one row. However, a second intermediary device and third-layer devices can be configured to be provided in a plurality of rows in parallel. For example, as in an air conditioning system <NUM> illustrated in <FIG>, a second intermediary device and third-layer devices may be configured to be provided in a plurality of rows in parallel. In the air conditioning system <NUM> in <FIG>, two second intermediary units <NUM>, which are second intermediary devices, are connected to the second line <NUM>. Each of the second intermediary units <NUM> is connected to two fourth indoor units <NUM> by the third line <NUM>.

In the third embodiment described above, a case has been described in which the second intermediary device is the second intermediary unit <NUM>. However, the second intermediary device is not limited to this. For example, the second intermediary device may be implemented using a power supply unit that supplies a direct-current voltage or an alternating-current voltage to indoor units.

(<NUM>-<NUM>)
In the air conditioning system <NUM>, the first line <NUM> and the second line <NUM> can always be connected by the first filter <NUM>. In the air conditioning system <NUM> according to the first embodiment or the modification illustrated in <FIG> or <FIG>, therefore, even if a failure has occurred in the first intermediary unit(s) <NUM>, which is a first intermediary device, a state can be maintained in which communication is possible between the outdoor unit <NUM>, which is a first-layer device, and the plurality of second indoor units <NUM>, which are second-layer devices. Further, in the air conditioning system <NUM> according to the second embodiment, the third embodiment, or the modification illustrated in <FIG>, <FIG>, or <FIG>, even if a failure has occurred in the outdoor unit <NUM>, which is a first intermediary device, a state can be maintained in which communication is possible between the centralized controller <NUM>, which is a first-layer device, and the plurality of outdoor units <NUM> and the plurality of third indoor units <NUM>, which are second-layer devices. Accordingly, the air conditioning system <NUM> can improve the reliability of communication.

(<NUM>-<NUM>)
In particular, in a case where second-layer devices are the plurality of second indoor units <NUM> or the plurality of third indoor units <NUM>, for example, even if a failure such as a breakdown occurs in the first intermediary unit <NUM> or the outdoor unit <NUM>, which is a first intermediary device, the outdoor unit <NUM> or the centralized controller <NUM> can maintain control. For example, the outdoor unit <NUM> or the centralized controller <NUM> can use a first signal to stop the operation of the plurality of second indoor units <NUM> or the plurality of third indoor units <NUM> through the first line <NUM> and the second line <NUM> or change the opening degrees of the expansion valves while operating the plurality of second indoor units <NUM> or the plurality of third indoor units <NUM>.

(<NUM>-<NUM>)
In the air conditioning system <NUM> according to the third embodiment described above or the modifications thereof, the second line <NUM> and the third line <NUM> are always connected by the second filter(s) <NUM>. In the air conditioning system <NUM> according to the third embodiment or the modification thereof illustrated in <FIG> or <FIG>, therefore, even if a failure has occurred in the second intermediary unit(s) <NUM>, which is a second intermediary device, a state can be maintained in which communication is possible between the centralized controller <NUM>, which is a first-layer device, and the outdoor unit <NUM> and the plurality of fourth indoor units <NUM>, which are second-layer devices. Accordingly, the air conditioning system <NUM> according to the third embodiment or the modification thereof can improve the reliability of communication.

(<NUM>-<NUM>)
In the air conditioning system <NUM>, in particular, in a case where a first-layer device is the outdoor unit <NUM> or the centralized controller <NUM>, even if a failure has occurred in the first intermediary unit <NUM> or the outdoor unit <NUM>, which is a first intermediary device and/or a second intermediary device, a state can be maintained in which the outdoor unit <NUM> or the centralized controller <NUM> can communicate with the first indoor unit <NUM>, the second indoor units <NUM>, the third indoor units <NUM>, and the fourth indoor units <NUM>. As a result, it is possible to prevent a failure caused by the outdoor unit <NUM> or the centralized controller <NUM> being no longer able to control the first indoor unit <NUM>, the second indoor units <NUM>, the third indoor units <NUM>, and the fourth indoor units <NUM>.

(<NUM>-<NUM>)
The outdoor unit <NUM> or the centralized controller <NUM>, which is a first-layer device, of the air conditioning system <NUM> can recognize the second indoor units <NUM> or the third indoor units <NUM>, which are second-layer devices, connected to the first intermediary unit <NUM> or the outdoor unit <NUM>, which is a first intermediary device, by the second line <NUM> by using the first intermediary unit <NUM> or the outdoor unit <NUM>. Therefore, for example, even if another device is connected between the outdoor unit <NUM> or the centralized controller <NUM> and the first intermediary unit <NUM> or the outdoor unit <NUM>, the outdoor unit <NUM> or the centralized controller <NUM> can recognize and manage the second indoor units <NUM> or the third indoor units <NUM> in a way distinguishable from the other device.

While embodiments of the present disclosure have been described, it will be understood that forms and details can be changed in various ways without departing from the scope of the present disclosure as recited in the claims.

Claim 1:
A network system (<NUM>) for a network in which a plurality of devices are classified into a plurality of layers, comprising:
a first-layer device (<NUM>, <NUM>, <NUM>);
a first line (<NUM>) connected to the first-layer device;
a second-layer device (<NUM>, <NUM>, <NUM>);
a second line (<NUM>) connected to the second-layer device; and
a first intermediary device (<NUM>, <NUM>) including a first filter (<NUM>) always connected to the first line and the second line, the first intermediary device being configured to communicate with the first-layer device and the second-layer device, characterized in that
the first filter is installed so as not to attenuate a high-frequency first signal used for communication among the first-layer device, the first intermediary device, and the second-layer device and so as to attenuate a low-frequency second signal used for communication between the first intermediary device and the second-layer device, other than the first-layer device.