Air Conditioning System

Abstract

This communication adapter (21) comprises a high-voltage communication unit (211) that performs high-voltage communication with an outdoor device (20), and a low-voltage communication unit (212) that performs low-voltage communication with a communication adapter (31). The low-voltage communication unit (212) transmits, via low-voltage communication, communication data received by the high-voltage communication unit (211) from the outdoor device (20) to the communication adapter (31). The high-voltage communication unit (211) transmits, via high-voltage communication, communication data received by the low-voltage communication unit (212) from the communication adapter (31) to the outdoor device (20).

Description

Communication adapter and air conditioning system

[0001] The present disclosure relates to a communication adapter and an air conditioning system.

[0002] In air conditioning systems installed in office buildings, stores, etc., a configuration in which the outdoor unit and the indoor unit are connected by a three-core cable including a power line, a signal line, and a common line is widely adopted (for example, Patent Document 1). In this configuration, a high voltage (for example, 200 VAC) is applied between the power line connected to an external power source and the common line, and power is supplied from the external power source to the indoor unit via the outdoor unit.

[0003] There are also known air conditioning systems that have separate external power supplies for the outdoor unit and the indoor unit. Even with such a configuration, a shared line is required for communication between the outdoor unit and the indoor unit, and a high voltage is applied to the shared line.

[0004] Patent No. 6239143

[0005] In North America and other markets, low-voltage (e.g., 24 VAC) wiring between air conditioners (outdoor and indoor units) is generally required. In order to use an air conditioning system with the above configuration in such countries, the installation costs would be high, and it is expected that local contractors will often refuse to install the system, which is one of the factors preventing sales expansion into this market.

[0006] For this reason, there is a demand for the proposal of a new technology that enables low-voltage wiring between air conditioners that are configured to communicate at high voltages.

[0007] The present disclosure has been made in consideration of the above-described circumstances, and aims to provide a communication adapter and an air conditioning system that enable low-voltage wiring between air conditioners configured to communicate at high voltage.

[0008] In order to achieve the above object, the communication adapter of the present disclosure comprises: a first communication unit that communicates with an air conditioner based on a first voltage; and a second communication unit that communicates with an apparatus other than the air conditioner based on a second voltage that is lower than the first voltage, wherein the second communication unit transmits communication data received from the air conditioner by the first communication unit to the apparatus based on the second voltage, and the first communication unit transmits communication data received from the apparatus by the second communication unit to the air conditioner based on the first voltage.

[0009] According to the present disclosure, it is possible to use low-voltage wiring between air conditioners configured to communicate at high voltage.

[0010] FIG. 1 is a diagram showing the overall configuration of an air conditioning system in embodiment 1. FIG. 2 is a block diagram showing the configuration of a control unit provided in an outdoor unit in embodiment 1. FIG. 3 is a circuit diagram showing the configuration of a high-voltage communication unit of an outdoor unit and a high-voltage communication unit of a communication adapter in embodiment 1. FIG. 4 is a diagram showing the overall configuration of an air conditioning system in embodiment 2. FIG. 5 is a diagram showing the overall configuration of an air conditioning system in embodiment 3. FIG. 6 is a timing chart showing the operation of each communication unit when communication data is transmitted from an outdoor unit to an indoor unit and when communication data is transmitted from an indoor unit to an outdoor unit in embodiment 3. FIG. 7 is a diagram showing the overall configuration of an air conditioning system in embodiment 4. FIG. 8 is a diagram showing the overall configuration of an air conditioning system in embodiment 5.

[0011] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the drawings.

[0012] (Embodiment 1) FIG. 1 is a diagram showing the overall configuration of an air conditioning system 1 according to Embodiment 1. The air conditioning system 1 is an example of an air conditioning system according to the present disclosure. The air conditioning system 1 is a system that provides air conditioning to a building, such as a building or a store, and includes an outdoor unit 2 and an indoor unit 3. Note that the air conditioning system 1 may also be configured to include multiple indoor units 3. In the air conditioning system 1, the outdoor unit 20 and the indoor unit 30 are connected via a refrigerant piping (not shown) for circulating the refrigerant. Furthermore, the communication adapter 21 of the outdoor unit 2 and the communication adapter 31 of the indoor unit 3 are connected to each other so as to be able to communicate with each other via a cable including two wires.

[0013] <Outdoor Unit 2> The outdoor unit 2 includes an outdoor unit 20 and a communication adapter 21. The communication adapter 21 is installed near the outdoor unit 20. Note that the communication adapter 21 may be installed inside the housing of the outdoor unit 20.

[0014] <<Outdoor Unit 20>> The outdoor unit 20 is an example of an air conditioner according to the present disclosure, and also an example of an outdoor unit according to the present disclosure. The outdoor unit 20 includes a power supply unit 200, a high-voltage communication unit 201, and a control unit 202. Although not shown, the outdoor unit 20 also includes mechanisms necessary for air conditioning, such as a compressor, an outdoor heat exchanger, an outdoor fan, and an expansion valve (hereinafter referred to as the "outdoor unit main unit").

[0015] The power supply unit 200 outputs power for driving the outdoor unit 20 based on power input from the external power supply 4. That is, the power supply unit 200 outputs the power required for the operation of the high-voltage communication unit 201, the control unit 202, and the outdoor unit main unit. The external power supply 4 is an AC power supply that supplies AC power, and is, for example, a commercial power supply that outputs a voltage of 200 V. Note that the external power supply 4 may also be, for example, a private power generator or a power supply based on renewable energy.

[0016] High-voltage communication unit 201, which will be described in detail later, is a communication circuit for communicating with other devices based on a first voltage (e.g., a voltage to ground of 200 V), and is configured to include electronic components such as transistors and photocouplers, and a communication driver integrated circuit (IC). Hereinafter, communication based on the first voltage will be referred to as high-voltage communication.

[0017] The control unit 202 performs overall control of the outdoor unit 20. As shown in Fig. 2, the control unit 202 includes a CPU (Central Processing Unit) 220, a ROM (Read-Only Memory) 221, a RAM (Random-Access Memory) 222, an I / O (Input / Output) interface 223, and an auxiliary storage device 224. The control unit 202 generates communication data (command data or notification data) for the indoor unit 30, performs processing based on the content of communication data received from the indoor unit 30, and controls the outdoor unit main unit. Command data refers to data that indicates instructions to other devices, and notification data refers to data to be notified to other devices (for example, response data to received command data).

[0018] <<Communication Adapter 21>> Returning to FIG. 1 , communication adapter 21 is an example of a communication adapter according to the present disclosure, and also an example of an outdoor unit adapter according to the present disclosure. Communication adapter 21 includes an insulated power supply unit 210, a high-voltage communication unit 211, a low-voltage communication unit 212, and a control unit 213. Insulated power supply unit 210 is an example of an insulated power supply unit according to the present disclosure. Insulated power supply unit 210 is a power supply circuit whose input and output are electrically insulated by reinforced insulation, and outputs power for driving communication adapter 21 based on power input from external power supply 4 via outdoor unit 20. That is, insulated power supply unit 210 outputs the power required for the operation of high-voltage communication unit 211, low-voltage communication unit 212, and control unit 213, respectively.

[0019] The high-voltage communication unit 211 is an example of a first communication unit according to the present disclosure. The high-voltage communication unit 211 is a communication circuit for high-voltage communication with other devices, and includes electronic components such as a transistor and a photocoupler, and a communication driver IC.

[0020] The low-voltage communication unit 212 is an example of a second communication unit according to the present disclosure. The low-voltage communication unit 212 is a communication circuit for communicating with other devices based on a second voltage (e.g., a voltage to ground of 5 V) that is lower than the first voltage, and is configured to include electronic components such as transistors and photocouplers, and a communication driver IC. Hereinafter, communication based on the second voltage will be referred to as low-voltage communication. Communication protocols for low-voltage communication include, for example, single-ended transmission such as RS-232C, differential transmission such as RS-485 or CAN (Controller Area Network), and Ethernet (registered trademark). In addition, the connection interface of the low-voltage communication unit 212 on the indoor unit 3 side is provided with reinforced insulation or double insulation from the external power supply 4.

[0021] The control unit 213 includes a CPU, a ROM, and a RAM, none of which are shown, and performs overall control of the communication adapter 21. The control unit 213 performs processing such as transmitting communication data received by the high-voltage communication unit 211 from the outdoor unit 20 to the indoor unit 3 via the low-voltage communication unit 212, and transmitting communication data received by the low-voltage communication unit 212 from the indoor unit 3 to the outdoor unit 20 via the high-voltage communication unit 211.

[0022] <Indoor unit 3> The indoor unit 3 includes an indoor unit 30 and a communication adapter 31. The communication adapter 31 is installed near the indoor unit 30. Note that the communication adapter 31 may be installed inside the housing of the indoor unit 30.

[0023] <<Indoor unit 30>> The indoor unit 30 is an example of an air conditioner according to the present disclosure, and also an example of an indoor unit according to the present disclosure. The indoor unit 30 includes a power supply unit 300, a high-voltage communication unit 301, and a control unit 302. Although not shown, the indoor unit 30 also includes mechanisms necessary for air conditioning, such as an indoor heat exchanger, a solenoid valve, and an indoor fan (hereinafter referred to as the "indoor unit main unit").

[0024] The power supply unit 300 outputs power for driving the indoor unit 30 based on power input from the external power supply 5. That is, the power supply unit 300 outputs the power required for the operation of the high-voltage communication unit 301, the control unit 302, and the indoor unit main unit. The external power supply 5 is, for example, a commercial power supply supplied by an electric power company. Note that the external power supply 5 may also be, for example, a private power generator or a power supply based on renewable energy.

[0025] The high-voltage communication unit 301, which will be described in detail later, is a communication circuit for high-voltage communication with other devices, and is configured to include electronic components such as transistors and photocouplers, as well as a communication driver IC. Similar to the control unit 202 of the outdoor unit 20 (see FIG. 2), the control unit 302 is equipped with a CPU, ROM, RAM, an I / O interface, and an auxiliary storage device, and performs overall control of the indoor unit 30. The control unit 302 generates communication data (command data or notification data) for the outdoor unit 20, performs processing based on the content of communication data received from the outdoor unit 20, controls the indoor unit main unit, etc.

[0026] <<Communication Adapter 31>> The communication adapter 31 is an example of a communication adapter according to the present disclosure, and also an example of an indoor unit adapter according to the present disclosure. The communication adapter 31 includes an insulated power supply unit 310, a high-voltage communication unit 311, a low-voltage communication unit 312, and a control unit 313. The insulated power supply unit 310 is an example of an insulated power supply unit according to the present disclosure. The insulated power supply unit 310 is a power supply circuit whose input and output are electrically insulated by reinforced insulation, and outputs power for driving the communication adapter 31 based on power input from the external power supply 5 via the indoor unit 30. In other words, the insulated power supply unit 310 supplies the high-voltage communication unit 311, the low-voltage communication unit 312, and the control unit 313 with the power required for their respective operations.

[0027] The high-voltage communication unit 311 is an example of a first communication unit according to the present disclosure, and is also an example of a third communication unit according to the present disclosure. The high-voltage communication unit 311, which will be described in detail later, is a communication circuit for high-voltage communication with other devices, and is configured to include electronic components such as transistors and photocouplers, and a communication driver IC.

[0028] The low-voltage communication unit 312 is an example of a second communication unit according to the present disclosure, and is also an example of a fourth communication unit according to the present disclosure. The low-voltage communication unit 312 is a communication circuit for low-voltage communication with other devices, and is configured to include electronic components such as transistors and photocouplers, and a communication driver IC. The connection interface of the low-voltage communication unit 312 on the outdoor unit 2 side is provided with reinforced insulation or double insulation from the external power supply 5.

[0029] The control unit 313 includes a CPU, a ROM, and a RAM, none of which are shown, and performs overall control of the communication adapter 31. The control unit 313 performs processing such as transmitting communication data received by the high-voltage communication unit 311 from the indoor unit 30 to the outdoor unit 2 via the low-voltage communication unit 312, and transmitting communication data received by the low-voltage communication unit 312 from the outdoor unit 2 to the indoor unit 30 via the high-voltage communication unit 311.

[0030] <High-Voltage Communication> High-voltage communication in this embodiment, i.e., high-voltage communication between the outdoor unit 20 and the communication adapter 21, and high-voltage communication between the indoor unit 30 and the communication adapter 31, will be described in detail below. Fig. 3 is a circuit diagram showing the configuration of the high-voltage communication section 201 of the outdoor unit 20 and the high-voltage communication section 211 of the communication adapter 21 in the outdoor unit 2. Note that in the indoor unit 3, the configuration of the high-voltage communication section 301 of the indoor unit 30 is similar to the configuration of the high-voltage communication section 211 shown in Fig. 3, and the configuration of the high-voltage communication section 311 of the communication adapter 31 is similar to the configuration of the high-voltage communication section 201 shown in Fig. 3.

[0031] 3 , the high-voltage communication unit 201 includes a DC power supply 400, a transmitting circuit 420, a receiving circuit 440, a communication driver IC 460, and a diode 470. The DC power supply 400 supplies a communication current used in serial communication. The DC power supply 400 converts AC power supplied from the external power supply 4 into DC power. The DC power supply 400 generates a communication voltage Vc (V) based on the potential of the common line 6. The DC power supply 400 is a half-wave rectifier circuit including a resistor 401, a diode 402, a constant voltage diode 403, and an electrolytic capacitor 404.

[0032] The resistor 401 is a resistor for generating a DC voltage. One end of the resistor 401 is connected to the external power supply 4 via the power line 7. The other end of the resistor 401 is connected to the anode of a diode 402. The diode 402 is a rectifying element that allows current to flow only in the direction from the anode to the cathode. The cathode of the diode 402 is connected to the cathode of a constant voltage diode 403, the positive terminal of an electrolytic capacitor 404, the emitter of a PNP (Positive Negative Positive) transistor 422 in the transmission circuit 420, one end of a resistor 423, and the collector of a phototransistor 432 in a photocoupler 430.

[0033] The constant voltage diode 403 is a diode in which almost no reverse current flows when the reverse voltage applied between the anode and cathode is less than the breakdown voltage, but when the reverse voltage exceeds the breakdown voltage, the reverse current suddenly begins to flow. The voltage across both ends of the constant voltage diode 403 (breakdown voltage) is assumed to be Vc (V). The anode of the constant voltage diode 403 is connected to the negative terminal of the electrolytic capacitor 404 and to the cathode of the diode 426 of the transmission circuit 420. The electrolytic capacitor 404 is a polarized capacitor that temporarily stores supplied energy.

[0034] The transmission circuit 420 is a circuit that transmits communication data by controlling the communication current that flows through the transmission path (i.e., high-voltage communication unit 201 → communication line 8 → high-voltage communication unit 211 → shared line 6 → high-voltage communication unit 201). Specifically, the transmission circuit 420 does not pass a communication current through the transmission path while the level of a PO (Parallel Output) terminal of the communication driver IC 460 is H level, and passes a communication current through the transmission path while the level of the PO terminal of the communication driver IC 460 is L level. Note that, for example, the H level is 5 V and the L level is 0 V. The transmission circuit 420 includes PNP transistors 421 and 422, resistors 423 to 425, a diode 426, a ground terminal 427, and a photocoupler 430.

[0035] The PNP transistor 421 is a switching element whose current path (the path between the emitter and collector) is provided on the transmission path. The PNP transistor 421 is controlled so as to be in the opposite conductive / non-conductive state to the phototransistor 432 of the photocoupler 430. The emitter of the PNP transistor 421 is connected to the base of the PNP transistor 422 and the other end of the resistor 423. The collector of the PNP transistor 421 is connected to one end of the resistor 444 in the receiving circuit 440 and to the anode of the light-emitting diode 451 of the photocoupler 450. The base of the PNP transistor 421 is connected to the collector of the PNP transistor 422, one end of the resistor 424, and the emitter of the phototransistor 432.

[0036] The PNP transistor 422, together with the resistor 423, limits the upper limit of the communication current flowing through the transmission path. The resistor 423 is a current-limiting resistor provided on the transmission path. When the communication current supplied from the DC power supply 400 causes the emitter-base voltage of the PNP transistor 422 (the voltage across the resistor 423) to exceed the saturation voltage (e.g., 0.6 V), the PNP transistor 422 turns ON. This causes current to flow through the resistor 424, making it difficult for current to flow through the current path of the PNP transistor 421. In other words, the upper limit of the communication current flowing through the communication line 8 connecting the high-voltage communication unit 201 of the outdoor unit 20 and the high-voltage communication unit 211 of the communication adapter 21 is limited by the resistance value of the resistor 423. In this way, the PNP transistor 422 and the resistor 423 serve to protect the circuit elements of the high-voltage communication unit 201 (e.g., the PNP transistor 421 and the photocoupler 450).

[0037] Resistor 424 is a base resistor that limits the base current that flows through PNP transistor 421. Resistor 424 also serves as a load resistor that limits the current that flows through phototransistor 432. Resistor 425 is a resistor that limits the current that flows through light-emitting diode 431 of photocoupler 430. One end of resistor 425 is connected to the anode of light-emitting diode 431, and the other end of resistor 425 is connected to the PO terminal of communication driver IC 460. Diode 426 is a rectifying element that allows current to flow only in the direction from the anode to the cathode. Ground terminal 427 is a terminal that is grounded and to which a ground potential is applied.

[0038] The photocoupler 430 is an element for electrically insulating two circuits from each other. The photocoupler 430 includes a light-emitting diode 431 and a phototransistor 432. When a primary current flows through the light-emitting diode 431, a secondary current flows through the current path of the phototransistor 432. Hereinafter, the current flowing through the light-emitting diode 431 will be referred to as the primary current, and the current flowing through the current path of the phototransistor 432 will be referred to as the secondary current, as appropriate. Furthermore, the voltage applied between the anode and cathode of the light-emitting diode 431 will be referred to as the primary voltage, and the voltage applied between the emitter and collector of the phototransistor 432 will be referred to as the secondary voltage.

[0039] When the voltage value of the primary side voltage becomes equal to or greater than a threshold, the light-emitting diode 431 flows a primary side current and emits light of an intensity corresponding to the current value of the primary side current. The cathode of the light-emitting diode 431 is connected to the ground terminal 427. The phototransistor 432 flows a secondary side current corresponding to the secondary side voltage and the intensity of the light emitted by the light-emitting diode 431 from the collector to the emitter.

[0040] The operation of the transmission circuit 420 will now be described. When the PO terminal of the communication driver IC 460 is at the H level, a current flows to the light-emitting diode 431 via the resistor 425. This causes the photocoupler 430 to turn on, and the current supplied from the DC power supply 400 flows to the shared line 6 via the phototransistor 432, the resistor 424, and the diode 426. Here, since the emitter-collector voltage when the phototransistor 432 is on does not exceed the emitter-base saturation voltage (e.g., about 0.6 V) of the PNP transistor 421, the PNP transistor 421 turns off, and no communication current flows through the transmission path.

[0041] On the other hand, when the PO terminal of the communication driver IC 460 is at the L level, no current flows through the light-emitting diode 431. As a result, the photocoupler 430 is turned OFF, and the base current of the PNP transistor 421 flows to the shared line 6 via the resistor 424 and the diode 426. This turns the PNP transistor 421 ON, and a communication current flows through the transmission path.

[0042] The receiving circuit 440 is a circuit that receives communication data by monitoring the communication current flowing through the transmission path. Specifically, the receiving circuit 440 sets a PI (Parallel Input) terminal of the communication driver IC 460 to an H level while a communication current is flowing through the transmission path, and sets the PI terminal of the communication driver IC 460 to an L level while no communication current is flowing through the transmission path. The receiving circuit 440 includes an NPN (Negative Positive Negative) transistor 441, resistors 442 to 444, a power supply terminal 445, ground terminals 446 to 447, and a photocoupler 450.

[0043] The NPN transistor 441 is provided to shorten the turn-off time of the photocoupler 450. The emitter of the NPN transistor 441 is connected to a ground terminal 446. The collector of the NPN transistor 441 is connected to one end of a resistor 442 and a PI terminal of the communication driver IC 460. The base of the NPN transistor 441 is connected to one end of a resistor 443 and a collector of a phototransistor 452 of the photocoupler 450. The resistor 442 is a resistor for pulling up the PI terminal of the communication driver IC 460 to an H level. The other end of the resistor 442 is connected to the other end of the resistor 443 and a power supply terminal 445.

[0044] The resistor 443 is a base resistor that limits the base current of the NPN transistor 441. The resistor 443 also serves as a load resistor that limits the current flowing through the phototransistor 452. The power supply terminal 445 is a terminal connected to the power supply unit 200. The potential of the power supply terminal 445 is at the H level (for example, 5 V). The ground terminals 446 and 447 are terminals that are grounded and to which a ground potential is applied. The ground terminals 446 and 447 can be considered to be connected to each other.

[0045] Resistor 444 is a threshold resistor for light-emitting diode 451. In other words, when the communication current is small and the voltage across resistor 444 is less than the forward voltage of light-emitting diode 451, the communication current flows entirely through resistor 444 and not through light-emitting diode 451. In contrast, when the communication current is large and the voltage across resistor 444 is equal to or greater than the forward voltage of light-emitting diode 451, the communication current also flows through light-emitting diode 451. The other end of resistor 444 is connected to the cathode of light-emitting diode 451 and the anode of diode 470.

[0046] The photocoupler 450 has basically the same configuration as the photocoupler 430. The photocoupler 450 includes a light-emitting diode 451 and a phototransistor 452. When a primary current flows through the light-emitting diode 451, a secondary current flows through the current path of the phototransistor 452.

[0047] The operation of the receiving circuit 440 will now be described. When a communication current flows through the transmission path, current flows through the light-emitting diode 451, turning the photocoupler 450 ON. As a result, current flows from the power supply terminal 445 to the ground terminal 447 via the resistor 443 and the phototransistor 452. As a result, the NPN transistor 441 is turned OFF, no current flows through the resistor 442, and the PI terminal of the communication driver IC 460 becomes H level.

[0048] On the other hand, if no communication current flows through the transmission path, no current flows through the light-emitting diode 451, and the photocoupler 450 is in the OFF state. As a result, no current flows through the phototransistor 452, and the NPN transistor 441 is in the ON state. As a result, current flows through the resistor 442, and the PI terminal of the communication driver IC 460 becomes the L level. Note that when the photocoupler 510 of the communication adapter 211 is in the ON state, a small communication current flows through the transmission path. However, if the communication current flowing through the transmission path is small, the voltage drop across the resistor 444 is small, and no current flows through the light-emitting diode 451. In other words, if the communication current is small, the photocoupler 450 is in the OFF state. Hereinafter, a case where the communication current is small will be treated the same as when no communication current is flowing.

[0049] The communication driver IC 460 controls the photocoupler 430 of the transmission circuit 420 to transmit communication data. The communication driver IC 460 also receives communication data based on the state of the photocoupler 450 of the reception circuit 440. The communication driver IC 460 includes a PO terminal that outputs a high-level or low-level voltage and a PI terminal that inputs a high-level or low-level voltage. The communication driver IC 460 switches the level of the voltage applied to the PO terminal between high and low levels depending on the communication data to be transmitted. The communication driver IC 460 also determines whether the voltage applied to the PI terminal is high or low. The communication driver IC 460 may include a digital input / output port.

[0050] Diode 470 is a rectifying element that allows current to flow only in the direction from the anode to the cathode. Diode 470 serves to block reverse current that may flow on the transmission path due to faulty wiring, etc. The cathode of diode 470 is connected to the anode of diode 541 of high-voltage communication unit 211.

[0051] <<High-Voltage Communication Unit 211>> The high-voltage communication unit 211 of the communication adapter 21 includes a transmission circuit 500, a reception circuit 520, a communication driver IC 540, a diode 541, and a constant-voltage diode 542. The transmission circuit 500 transmits communication data by controlling the communication current flowing through the transmission path. Specifically, the transmission circuit 500 does not pass a communication current through the transmission path while the level of the PO terminal of the communication driver IC 540 is H level, and passes a communication current through the transmission path while the level of the PO terminal of the communication driver IC 540 is L level. The transmission circuit 500 includes a PNP transistor 501, resistors 502 to 504, a ground terminal 505, and a photocoupler 510.

[0052] The PNP transistor 501 is a switching element whose current path is provided on the transmission path. The PNP transistor 501 is controlled to be in the opposite conductive / non-conductive state to the phototransistor 512 of the photocoupler 510. The emitter of the PNP transistor 501 is connected to the collector of the phototransistor 512 and the cathode of the diode 541. The collector of the PNP transistor 501 is connected to one end of the resistor 502. The base of the PNP transistor 501 is connected to one end of the resistor 503 and the emitter of the phototransistor 512.

[0053] Resistor 502 is a resistor that limits the communication current flowing through the transmission path. The other end of resistor 502 is connected to the anode of light-emitting diode 531 of photocoupler 530 in receiving circuit 520. Resistor 503 is a base resistor that limits the base current flowing through PNP transistor 501. Resistor 503 also serves as a load resistor that limits the current flowing through phototransistor 512. Here, the resistance value of resistor 503 is sufficiently larger than the resistance value of resistor 502. Therefore, the current value of the communication current flowing through resistor 503 when photocoupler 510 is in the ON state is sufficiently smaller than the current value of the communication current flowing through resistor 502 when photocoupler 510 is in the OFF state.

[0054] With this configuration, when the photocoupler 510 is turned on, the photocoupler 450 of the high-voltage communication unit 201 is turned off, and when the photocoupler 510 is turned off, the photocoupler 450 is turned on. The other end of the resistor 503 is connected to the cathode of the light-emitting diode 531 and the anode of the constant voltage diode 542.

[0055] The resistor 504 is a resistor that limits the current flowing through the light-emitting diode 511 of the photocoupler 510. In other words, the resistor 504 serves to protect the circuit elements (e.g., the PNP transistor 501 and the photocoupler 530) of the high-voltage communication unit 211. One end of the resistor 504 is connected to the anode of the light-emitting diode 511. The other end of the resistor 504 is connected to the PO terminal of the communication driver IC 540. The ground terminal 505 is a terminal that is grounded and to which a ground potential is applied. The ground terminal 505 is connected to the cathode of the light-emitting diode 511.

[0056] Photocoupler 510 basically has the same configuration as photocoupler 430 in transmission circuit 420 of high-voltage communication unit 201. Photocoupler 510 includes a light-emitting diode 511 and a phototransistor 512. When a primary current flows through light-emitting diode 511 of photocoupler 510, a secondary current flows through the current path of phototransistor 512.

[0057] The operation of the transmission circuit 500 will now be described. When the PO terminal of the communication driver IC 540 is at the H level, current flows to the light-emitting diode 511 via the resistor 504. This turns the photocoupler 510 ON, and the communication current supplied from the communication line 8 flows to the shared line 6 via the phototransistor 512 and the resistor 503. However, because the resistance value of the resistor 503 is high, only a small amount of communication current flows. Here, because the emitter-collector voltage when the phototransistor 512 is ON does not exceed the emitter-base saturation voltage (e.g., about 0.6 V) of the PNP transistor 501, the PNP transistor 501 is OFF, and almost no communication current flows through the transmission path.

[0058] On the other hand, when the PO terminal of the communication driver IC 540 is at the L level, no current flows through the light-emitting diode 511. As a result, the photocoupler 510 is turned OFF, and the base current of the PNP transistor 501 flows through the resistor 503 to the shared line 6. Therefore, the PNP transistor 501 is turned ON, and a communication current flows through the transmission path.

[0059] The receiving circuit 520 is a circuit that receives communication data by monitoring the communication current flowing through the transmission path. Specifically, the receiving circuit 520 sets the PI terminal of the communication driver IC 540 to the H level while the communication current is flowing through the transmission path, and sets the PI terminal of the communication driver IC 540 to the L level while the communication current is not flowing through the transmission path. The receiving circuit 520 includes an NPN transistor 521, resistors 522 and 523, a power supply terminal 524, ground terminals 525 and 526, and a photocoupler 530.

[0060] The NPN transistor 521 is provided to shorten the turn-off time of the photocoupler 530. The emitter of the NPN transistor 521 is connected to a ground terminal 525. The collector of the NPN transistor 521 is connected to one end of a resistor 522 and the PI terminal of the communication driver IC 540. The base of the NPN transistor 521 is connected to one end of a resistor 523 and the collector of a phototransistor 532 of the photocoupler 530. The resistor 522 is a resistor for pulling up the PI terminal of the communication driver IC 540 to an H level. The other end of the resistor 522 is connected to the other end of the resistor 523 and the power supply terminal 524.

[0061] The resistor 523 is a base resistor that limits the base current of the NPN transistor 521. The resistor 523 also serves as a load resistor that limits the current flowing through the phototransistor 532. The power supply terminal 524 is a terminal connected to the insulated power supply unit 210. The potential of the power supply terminal 524 is at the H level. The ground terminals 525 and 526 are terminals that are grounded and to which a ground potential is applied. The ground terminals 525 and 526 can be considered to be connected to each other.

[0062] Photocoupler 530 basically has the same configuration as photocoupler 450 in receiving circuit 440 of high-voltage communication unit 201. Photocoupler 530 includes a light-emitting diode 531 and a phototransistor 532. When a primary current flows through light-emitting diode 531 of photocoupler 530, a secondary current flows through the current path of phototransistor 532.

[0063] The operation of the receiving circuit 520 will now be described. When a communication current flows through the transmission path, current flows through the light-emitting diode 531, turning the photocoupler 530 ON. As a result, current flows from the power supply terminal 524 to the ground terminal 526 via the resistor 523 and the phototransistor 532. This turns the NPN transistor 521 OFF, no current flows through the resistor 522, and the PI terminal of the communication driver IC 540 goes high.

[0064] On the other hand, when no communication current flows through the transmission path, no current flows through the light-emitting diode 531, and the photocoupler 530 is turned off. As a result, no current flows through the phototransistor 532, and the NPN transistor 521 is turned on. As a result, current flows through the resistor 522, and the PI terminal of the communication driver IC 540 becomes low level.

[0065] The communication driver IC 540 controls the photocoupler 510 of the transmission circuit 500 to transmit communication data. The communication driver IC 540 also receives communication data based on the state of the photocoupler 530 of the reception circuit 520. The communication driver IC 540 includes a PO terminal that outputs a high-level or low-level voltage and a PI terminal that inputs a high-level or low-level voltage. The communication driver IC 540 switches the level of the voltage applied to the PO terminal between high and low levels depending on the data to be transmitted. The communication driver IC 540 also determines whether the voltage applied to the PI terminal is high or low. The communication driver IC 540 may include a digital input / output port.

[0066] The diode 541 is a rectifying element that allows current to flow only in the direction from the anode to the cathode. The diode 541 serves to block reverse current that may flow on the transmission path due to incorrect wiring or the like. The voltage regulator diode 542 is a diode that allows almost no reverse current to flow when the reverse voltage applied between the anode and cathode is less than the breakdown voltage, but allows the reverse current to flow suddenly when the reverse voltage exceeds the breakdown voltage. The voltage regulator diode 542 serves to protect the circuit elements of the high-voltage communication unit 211 (e.g., the PNP transistor 501, the photocoupler 510, and the photocoupler 530).

[0067] <Operation of Air Conditioning System 1> Next, the operation of the air conditioning system 1 relating to the transmission and reception of communication data will be described.

[0068] <<When transmitting communication data from the outdoor unit 20 to the indoor unit 30>> (1) The outdoor unit 20 of the outdoor unit 2 transmits communication data to the communication adapter 21 via high-voltage communication. The communication data includes information indicating the sender and destination. (2) The communication adapter 21 receives the communication data from the outdoor unit 20 via high-voltage communication. (3) The communication adapter 21 transmits the received communication data from the outdoor unit 20 to the communication adapter 31 of the indoor unit 3 via low-voltage communication.

[0069] (4) The communication adapter 31 of the indoor unit 3 receives communication data from the communication adapter 21 of the outdoor unit 2 via low-voltage communication. (5) The communication adapter 31 transmits the received communication data from the outdoor unit 2 to the indoor unit 30 via high-voltage communication. (6) The indoor unit 30 receives the communication data from the communication adapter 31 via high-voltage communication. (7) The indoor unit 30 analyzes the received communication data and executes processing based on the content of the communication data.

[0070] <<When transmitting communication data from the indoor unit 30 to the outdoor unit 20>> (1) The indoor unit 30 of the indoor unit 3 transmits communication data to the communication adapter 31 via high-voltage communication. The communication data includes information indicating the sender and destination. (2) The communication adapter 31 receives the communication data from the indoor unit 30 via high-voltage communication. (3) The communication adapter 31 transmits the received communication data from the indoor unit 30 to the communication adapter 21 of the outdoor unit 2 via low-voltage communication.

[0071] (4) The communication adapter 21 of the outdoor unit 2 receives communication data from the communication adapter 31 of the indoor unit 3 via low-voltage communication. (5) The communication adapter 21 transmits the received communication data from the indoor unit 3 to the outdoor unit 20 via high-voltage communication. (6) The outdoor unit 20 receives the communication data from the communication adapter 21 via high-voltage communication. (7) The outdoor unit 20 analyzes the received communication data and executes processing based on the content of the communication data.

[0072] As described above, the air conditioning system 1 in this embodiment is equipped with the communication adapter 21 that performs high-voltage communication with the outdoor unit 20 and low-voltage communication with devices other than the outdoor unit 20, and the communication adapter 31 that performs high-voltage communication with the indoor unit 30 and low-voltage communication with devices other than the indoor unit 30. Therefore, by connecting the outdoor unit 20 and the communication adapter 21 and the indoor unit 30 and the communication adapter 31 at the time of factory shipment, high-voltage wiring work on-site is not required. This is expected to expand sales channels to markets where low-voltage wiring between air conditioners is required.

[0073] Furthermore, in the communication adapter 21, the insulated power supply unit 210 receives power from the external power supply 4, but the input and output are electrically insulated by reinforced insulation, and the connection interface of the low-voltage communication unit 212 on the indoor unit 3 side is provided with reinforced insulation or double insulation from the external power supply 4. Similarly, in the communication adapter 31, the insulated power supply unit 310 receives power from the external power supply 5, but the input and output are electrically insulated by reinforced insulation, and the connection interface of the low-voltage communication unit 312 on the outdoor unit 2 side is provided with reinforced insulation or double insulation from the external power supply 5. This will further promote the expansion of sales channels into the above-mentioned markets.

[0074] Second Embodiment Next, a second embodiment of the present disclosure will be described. In the following description, components and the like common to the first embodiment will be denoted by the same reference numerals, and description thereof will be omitted.

[0075] 4 is a diagram showing the overall configuration of an air conditioning system 1A according to embodiment 2. The air conditioning system 1A is an example of an air conditioning system according to the present disclosure. The air conditioning system 1A is a system that provides air conditioning for a building such as a building or store, and includes an outdoor unit 2A and an indoor unit 3A. Note that the air conditioning system 1A may also be configured to include multiple indoor units 3A.

[0076] <Outdoor unit 2A> The outdoor unit 2A includes an outdoor unit 20A and a communication adapter 21A. The communication adapter 21A is installed near the outdoor unit 20A. Note that the communication adapter 21A may be configured to be installed inside the housing of the outdoor unit 20A.

[0077] <<Outdoor Unit 20A>> The outdoor unit 20A is an example of an air conditioner according to the present disclosure, and also an example of an outdoor unit according to the present disclosure. Like the outdoor unit 20 in embodiment 1, the outdoor unit 20A includes a power supply unit 200, a high-voltage communication unit 201, a control unit 202, and an outdoor unit main unit (not shown). The outdoor unit 20A differs from the outdoor unit 20 in that the outdoor unit 20A is configured so that power is supplied from the power supply unit 200 to an insulated power supply unit 210 of the communication adapter 21A, but in other respects the configurations of the two are the same.

[0078] <<Communication Adapter 21A>> The communication adapter 21A is an example of a communication adapter according to the present disclosure, and also an example of an outdoor unit adapter according to the present disclosure. Like the communication adapter 21 in embodiment 1, the communication adapter 21A includes an insulated power supply unit 210, a high-voltage communication unit 211, a low-voltage communication unit 212, and a control unit 213. The communication adapter 21A differs from the communication adapter 21 in that the communication adapter 21A is configured so that power is input to the insulated power supply unit 210 from the power supply unit 200 of the outdoor unit 20A rather than from the external power supply 4; in other respects, the configurations of the two are the same.

[0079] <Indoor unit 3A> The indoor unit 3A includes an indoor unit 30A and a communication adapter 31 A. The communication adapter 31A is installed near the indoor unit 30A. Note that the communication adapter 31A may be configured to be installed inside the housing of the indoor unit 30A.

[0080] <<Indoor unit 30A>> The indoor unit 30A is an example of an air conditioner according to the present disclosure, and also an example of an indoor unit according to the present disclosure. Similar to the indoor unit 30 in embodiment 1, the indoor unit 30A includes a power supply unit 300, a high-voltage communication unit 301, a control unit 302, and an indoor unit main unit (not shown). The indoor unit 30A differs from the indoor unit 30 in that the indoor unit 30A is configured so that power is supplied from the power supply unit 300 to an insulated power supply unit 310 of the communication adapter 31A, but in other respects the configurations of the two are the same.

[0081] <<Communication Adapter 31A>> The communication adapter 31A is an example of a communication adapter according to the present disclosure, and also an example of an indoor unit adapter according to the present disclosure. Like the communication adapter 31 in embodiment 1, the communication adapter 31A includes an insulated power supply unit 310, a high-voltage communication unit 311, a low-voltage communication unit 312, and a control unit 313. The communication adapter 31A differs from the communication adapter 31 in that the communication adapter 31A is configured so that power is input to the insulated power supply unit 310 from the power supply unit 300 of the indoor unit 30A rather than from the external power supply 5; in other respects, the configurations of the two adapters are the same.

[0082] As described above, the air conditioning system 1A in this embodiment is equipped with a communication adapter 21A that performs high-voltage communication with the outdoor unit 20A and low-voltage communication with devices other than the outdoor unit 20A, and a communication adapter 31A that performs high-voltage communication with the indoor unit 30A and low-voltage communication with devices other than the indoor unit 30A. Therefore, by connecting the outdoor unit 20A and the communication adapter 21A and the indoor unit 30A and the communication adapter 31A at the time of factory shipment, high-voltage wiring work on-site is not required. This is expected to expand sales channels to markets where low-voltage wiring between air conditioners is required.

[0083] Furthermore, in the communication adapter 21A, the insulated power supply unit 210 receives power from the power supply unit 200 of the outdoor unit 20, but the input and output are electrically insulated by reinforced insulation, and further, the connection interface of the low-voltage communication unit 212 on the indoor unit 3A side is provided with reinforced insulation or double insulation from the external power supply 4. Similarly, in the communication adapter 31A, the insulated power supply unit 310 receives power from the power supply unit 300 of the indoor unit 30A, but the input and output are electrically insulated by reinforced insulation, and further, the connection interface of the low-voltage communication unit 312 on the outdoor unit 2A side is provided with reinforced insulation or double insulation from the external power supply 5. This will further promote the expansion of sales channels into the above-mentioned markets.

[0084] Furthermore, since the voltage output from the power supply unit 200 of the outdoor unit 20A is lower than the voltage output from the external power supply 4, it is possible to reduce the size of the insulated power supply unit 210 in the communication adapter 21A. Similarly, since the voltage output from the power supply unit 300 of the indoor unit 30A is lower than the voltage output from the external power supply 5, it is possible to reduce the size of the insulated power supply unit 310 in the communication adapter 31A.

[0085] Third Embodiment Next, a third embodiment of the present disclosure will be described. In the following description, components and the like common to the first embodiment will be denoted by the same reference numerals, and description thereof will be omitted.

[0086] 5 is a diagram showing the overall configuration of an air conditioning system 1B according to embodiment 3. Air conditioning system 1B is an example of an air conditioning system according to the present disclosure. Air conditioning system 1B is a system that provides air conditioning for a building such as a building or store, and includes an outdoor unit 2B and an indoor unit 3B. Note that air conditioning system 1B may also be configured to include multiple indoor units 3B.

[0087] <Outdoor unit 2B> The outdoor unit 2B includes an outdoor unit 20 and a communication adapter 21B. The communication adapter 21B is installed near the outdoor unit 20. Note that the communication adapter 21B may be configured to be installed inside the housing of the outdoor unit 20.

[0088] <<Communication Adapter 21B>> Communication adapter 21B is an example of a communication adapter according to the present disclosure, and also an example of an outdoor unit adapter according to the present disclosure. Communication adapter 21B includes an insulated power supply unit 210, a high-voltage communication unit 211, and a low-voltage communication unit 212A. Low-voltage communication unit 212A is an example of a second communication unit according to the present disclosure. Similar to low-voltage communication unit 212 in the first embodiment, low-voltage communication unit 212A is a communication circuit for low-voltage communication with other devices, and is configured to include electronic components such as transistors and photocouplers, and a communication driver IC.

[0089] The low-voltage communication unit 212A communicates with other devices using a full-duplex communication method (for example, four-wire RS-485). The high-voltage communication unit 211 and the low-voltage communication unit 212A are cross-connected so that the transmission signal lines and reception signal lines are interchanged. As in the first embodiment, the connection interface of the low-voltage communication unit 212A on the indoor unit 3B side is provided with reinforced insulation or double insulation from the external power supply 4.

[0090] <Indoor unit 3B> The indoor unit 3B includes an indoor unit 30 and a communication adapter 31B. The communication adapter 31B is installed near the indoor unit 30. Note that the communication adapter 31B may be configured to be installed inside the housing of the indoor unit 30.

[0091] <<Communication Adapter 31B>> Communication adapter 31B is an example of a communication adapter according to the present disclosure, and also an example of an indoor unit adapter according to the present disclosure. Communication adapter 31B includes an insulated power supply unit 310, a high-voltage communication unit 311, and a low-voltage communication unit 312A. Low-voltage communication unit 312A is an example of a second communication unit according to the present disclosure, and also an example of a fourth communication unit according to the present disclosure. Similar to low-voltage communication unit 312 in the first embodiment, low-voltage communication unit 312A is a communication circuit for low-voltage communication with other devices, and includes electronic components such as transistors and photocouplers, and a communication driver IC.

[0092] The low-voltage communication unit 312A communicates with other devices using a full-duplex communication method (for example, four-wire RS-485). The high-voltage communication unit 311 and the low-voltage communication unit 312A are cross-connected so that the transmission signal lines and reception signal lines are interchanged. As in the first embodiment, the connection interface of the low-voltage communication unit 312A on the outdoor unit 2B side is provided with reinforced insulation or double insulation from the external power supply 5.

[0093] Fig. 6 is a timing chart showing the operation of each communication unit (high-voltage communication unit 201, high-voltage communication unit 211, low-voltage communication unit 212A, high-voltage communication unit 301, high-voltage communication unit 311, and low-voltage communication unit 312A) in air conditioning system 1B when communication data is transmitted between outdoor unit 20 and indoor unit 30, and when communication data is transmitted from indoor unit 30 to outdoor unit 20. In Fig. 6, when the high-voltage communication unit is ON, this indicates that the transmission path is in a conductive state, i.e., a state in which a communication current is flowing through the transmission path, and when the high-voltage communication unit is OFF, this indicates that the transmission path is in a non-conductive state, i.e., a state in which a communication current is not flowing through the transmission path.

[0094] As described above, the air conditioning system 1B in this embodiment is equipped with a communication adapter 21B that performs high-voltage communication with the outdoor unit 20 and low-voltage communication with devices other than the outdoor unit 20, and a communication adapter 31B that performs high-voltage communication with the indoor unit 30 and low-voltage communication with devices other than the indoor unit 30. Therefore, by connecting the outdoor unit 20 and the communication adapter 21B and the indoor unit 30 and the communication adapter 31B at the time of factory shipment, high-voltage wiring work on-site is not required. This is expected to expand sales channels to markets where low-voltage wiring between air conditioners is required.

[0095] In addition, in communication adapter 21B, power is input from external power supply 4 to insulated power supply unit 210, but the input and output are electrically insulated by reinforced insulation, and further, the connection interface of low-voltage communication unit 212A on the indoor unit 3B side is provided with reinforced insulation or double insulation from the external power supply 4. Similarly, in communication adapter 31B, power is input from external power supply 5 to insulated power supply unit 310, but the input and output are electrically insulated by reinforced insulation, and further, the connection interface of low-voltage communication unit 312A on the outdoor unit 2B side is provided with reinforced insulation or double insulation from the external power supply 5. This will further promote the expansion of sales channels into the above-mentioned markets.

[0096] Furthermore, in communication adapter 21B, low-voltage communication unit 212A communicates with other devices using full-duplex communication, and high-voltage communication unit 211 and low-voltage communication unit 212A are cross-connected so that the transmission signal line and the reception signal line alternate with each other. This eliminates the need for control unit 213 in embodiment 1 in communication adapter 21B, allowing for downsizing. Similarly, in communication adapter 31B, low-voltage communication unit 312A communicates with other devices using full-duplex communication, and high-voltage communication unit 311 and low-voltage communication unit 312A are cross-connected so that the transmission signal line and the reception signal line alternate with each other. This eliminates the need for control unit 313 in embodiment 1 in communication adapter 31B, allowing for downsizing.

[0097] Fourth Embodiment Next, a fourth embodiment of the present disclosure will be described. In the following description, components and the like common to the first embodiment will be denoted by the same reference numerals, and description thereof will be omitted.

[0098] 7 is a diagram showing the overall configuration of an air conditioning system 1C according to embodiment 4. Air conditioning system 1C is an example of an air conditioning system according to the present disclosure. Air conditioning system 1C is a system that provides air conditioning for a building such as a building or store, and includes an outdoor unit 2 and an indoor unit 30B. Note that air conditioning system 1C may also be configured to include multiple indoor units 30B.

[0099] The indoor unit 30B is an example of an indoor unit according to the present disclosure. The indoor unit 30B includes an insulated power supply unit 303, a low-voltage communication unit 304, a control unit 302, and an indoor unit main unit (not shown). The insulated power supply unit 303 is a power supply circuit whose input and output are electrically isolated by reinforced insulation, and outputs the power required for the operation of the low-voltage communication unit 304, the control unit 302, and the indoor unit main unit based on the power input from the external power supply 5.

[0100] The low-voltage communication unit 304 is a communication circuit for low-voltage communication with other devices, and is configured to include electronic components such as transistors and photocouplers, and a communication driver IC. Communication protocols for low-voltage communication include, for example, single-ended transmission such as RS232C, differential transmission such as RS-485 and CAN, and Ethernet (registered trademark). In addition, the connection interface of the low-voltage communication unit 304 on the outdoor unit 2 side is provided with reinforced insulation or double insulation from the external power supply 5.

[0101] As explained above, the air conditioning system 1C in this embodiment comprises the communication adapter 21 that performs high-voltage communication with the outdoor unit 20 and low-voltage communication with devices other than the outdoor unit 20, and the indoor unit 30B that performs low-voltage communication with other devices. Therefore, by connecting the outdoor unit 20 and the communication adapter 21 at the time of factory shipment, high-voltage wiring work on-site is not required. This is expected to expand sales channels to markets that require low-voltage wiring between air conditioners.

[0102] Furthermore, in the communication adapter 21, the insulated power supply unit 210 receives power from the external power supply 4, but the input and output are electrically insulated by reinforced insulation, and the connection interface of the low-voltage communication unit 212 on the indoor unit 30B side is provided with reinforced insulation or double insulation from the external power supply 4. Furthermore, in the indoor unit 30B, the insulated power supply unit 303 receives power from the external power supply 5, but the input and output are electrically insulated by reinforced insulation, and the connection interface of the low-voltage communication unit 304 on the outdoor unit 2 side is provided with reinforced insulation or double insulation from the external power supply 5. This will further promote the expansion of sales channels into the above-mentioned markets.

[0103] Fifth Embodiment Next, a fifth embodiment of the present disclosure will be described. In the following description, components and the like common to the first embodiment will be denoted by the same reference numerals, and description thereof will be omitted.

[0104] 8 is a diagram showing the overall configuration of an air conditioning system 1D according to embodiment 5. The air conditioning system 1D is an example of an air conditioning system according to the present disclosure. The air conditioning system 1D is a system that provides air conditioning for a building such as a building or a store, and includes an outdoor unit 20B and an indoor unit 3. Note that the air conditioning system 1D may be configured to include multiple indoor units 3.

[0105] The outdoor unit 20B includes an insulated power supply unit 203, a low-voltage communication unit 204, a control unit 202, and an outdoor unit main unit (not shown). The insulated power supply unit 203 is a power supply circuit whose input and output are electrically insulated by reinforced insulation, and based on power input from the external power supply 4, outputs the power required for the operation of the low-voltage communication unit 204, the control unit 202, and the outdoor unit main unit.

[0106] The low-voltage communication unit 204 is a communication circuit for low-voltage communication with other devices, and is configured to include electronic components such as transistors and photocouplers, and a communication driver IC. Communication protocols for low-voltage communication include, for example, single-ended transmission such as RS232C, differential transmission such as RS-485 and CAN, and Ethernet (registered trademark). In addition, the connection interface of the low-voltage communication unit 204 on the indoor unit 3 side is provided with reinforced insulation or double insulation from the external power supply 4.

[0107] As explained above, the air conditioning system 1D in this embodiment includes the outdoor unit 20B configured to perform low-voltage communication with other devices, and the communication adapter 31 that performs low-voltage communication with devices other than the indoor unit 30. Therefore, by connecting the indoor unit 30 and the communication adapter 31 at the time of factory shipment, high-voltage wiring work on-site is not required. This is expected to expand sales channels to markets that require low-voltage wiring between air conditioners.

[0108] Furthermore, in the communication adapter 31, the insulated power supply unit 310 receives power from the external power supply 5, but the input and output are electrically insulated by reinforced insulation, and the connection interface of the low-voltage communication unit 312 on the outdoor unit 20B side is provided with reinforced insulation or double insulation from the external power supply 5. Furthermore, in the outdoor unit 20B, the insulated power supply unit 203 receives power from the external power supply 4, but the input and output are electrically insulated by reinforced insulation, and the connection interface of the low-voltage communication unit 204 on the indoor unit 3 side is provided with reinforced insulation or double insulation from the external power supply 4. This will further promote the expansion of sales channels into the above-mentioned markets.

[0109] The present disclosure is not limited to the above-described embodiments, and various modifications are possible without departing from the spirit of the present disclosure. For example, the technical ideas of the above-described embodiments can be combined as appropriate.

[0110] The present disclosure allows various embodiments and modifications without departing from the broad spirit and scope. Furthermore, the above-described embodiments are intended to explain the present disclosure and do not limit the scope of the present disclosure. In other words, the scope of the present disclosure is defined by the claims, not the embodiments. Various modifications made within the scope of the claims and within the meaning of the disclosure equivalent thereto are considered to be within the scope of the present disclosure.

[0111] The present disclosure can be suitably employed in a system for air conditioning a building.

[0112] 1, 1A, 1B, 1C, 1D Air conditioning system, 2, 2A, 2B Outdoor unit, 3, 3A, 3B Indoor unit, 4, 5 External power supply, 6 Shared line, 7 Power supply line, 8 Communication line, 20, 20A, 20B Outdoor unit, 21, 21A, 21B, 31, 31A, 31B Communication adapter, 30, 30A, 30B Indoor unit, 200, 300 Power supply unit, 201, 211, 301, 311 High voltage communication unit, 202, 213, 302, 313 Control unit, 203, 210, 303, 310 Insulated power supply unit, 204, 212, 212A, 304, 312, 312A Low voltage communication unit, 220 CPU, 221 ROM, 222 RAM, 223 I / O interface, 224 Auxiliary storage device, 400 DC power supply, 401, 423, 424, 425, 442, 443, 444, 502, 503, 504, 522, 523 Resistor, 402, 426, 470, 541 Diode, 403, 542 Low voltage diode, 404 Electrolytic capacitor, 420, 500 Transmitting circuit, 421, 422, 501 PNP transistor, 427, 446, 447, 505, 525, 526 Ground terminal, 430, 450, 510, 530 Photocoupler, 431, 451, 511, 531 Light emitting diode, 432, 452, 512, 532 Phototransistor, 440, 520 Receiving circuit, 441, 521 NPN transistor, 445, 524 Power supply terminal, 460, 540 Communication driver IC

Claims

1. an outdoor unit that communicates based on a first voltage; an indoor unit that communicates based on the first voltage; An outdoor unit adapter; An indoor unit adapter; The outdoor unit adapter is A first communication unit that communicates with the outdoor unit based on the first voltage; a second communication unit that communicates with the indoor unit adapter based on a second voltage that is lower than the first voltage, the second communication unit transmits communication data received by the first communication unit from the outdoor unit to the indoor unit adapter based on the second voltage; the first communication unit transmits communication data received by the second communication unit from the indoor unit adapter to the outdoor unit based on the first voltage; the outdoor unit and the outdoor unit adapter are connected by a first communication line that causes a current supplied from a DC power supply included in the outdoor unit to flow to the outdoor unit adapter, and a first shared line that causes a current that has flowed through the first communication line to flow from the outdoor unit adapter to the outdoor unit, The first communication unit is a first transmission circuit including a first transmitting photocoupler whose conductive / non-conductive state is controlled in response to communication data to be transmitted to the outdoor unit, and which controls the conductive / non-conductive state of a first transmission path including the first communication line and the first shared line in response to the conductive / non-conductive state of the first transmitting photocoupler; a first receiving circuit that includes a first receiving photocoupler whose conductive / non-conductive state is controlled in response to a conductive / non-conductive state of the first transmission path, and receives communication data transmitted from the outdoor unit by detecting the conductive / non-conductive state of the first receiving photocoupler, The indoor unit adapter is A third communication unit that communicates with the indoor unit based on the first voltage; a fourth communication unit that communicates with the outdoor unit adapter based on the second voltage, the fourth communication unit transmits communication data received by the third communication unit from the indoor unit to the outdoor unit adapter based on the second voltage; The third communication unit transmits communication data received by the fourth communication unit from the outdoor unit adapter to the indoor unit based on the first voltage, The indoor unit and the indoor unit adapter are connected by a second communication line that passes a current supplied from a DC power supply provided in the indoor unit adapter to the indoor unit, and a second shared line that passes a current that has passed through the second communication line from the indoor unit to the indoor unit adapter, The third communication unit is a second transmission circuit including a second transmitting photocoupler whose conductive / non-conductive state is controlled in response to communication data to be transmitted to the indoor unit, and which controls the conductive / non-conductive state of a second transmission path including the second communication line and the second shared line in response to the conductive / non-conductive state of the second transmitting photocoupler; a second receiving photocoupler whose conductive / non-conductive state is controlled in response to the conductive / non-conductive state of the second transmission path, and a second receiving circuit that receives communication data transmitted from the indoor unit by detecting the conductive / non-conductive state of the second receiving photocoupler; Air conditioning system.

2. The outdoor unit adapter is a first insulated power supply unit whose input and output are electrically insulated and which outputs power for driving the outdoor unit adapter based on power input from a first external power supply; The indoor unit adapter is The indoor unit adaptor further includes a second insulated power supply unit whose input and output are electrically insulated and which outputs power for driving the indoor unit adaptor based on power input from a second external power supply. The air conditioning system of claim 1 .

3. A connection interface between the second communication unit and the indoor unit adapter is reinforced insulated or double insulated with respect to the first external power source, A connection interface between the fourth communication unit and the outdoor unit adapter is reinforced insulated or double insulated with respect to the second external power source.

3. The air conditioning system according to claim 2.

4. The communication between the second communication unit and the indoor unit adapter is performed in a full-duplex communication manner, A transmission signal line and a reception signal line are connected between the first communication unit and the second communication unit so as to be interchangeable with each other; communication between the fourth communication unit and the outdoor unit adapter is performed in a full-duplex communication system; A transmission signal line and a reception signal line are connected so as to be interchangeable between the third communication unit and the fourth communication unit. An air conditioning system according to any one of claims 1 to 3.

5. an outdoor unit that communicates based on a first voltage; an indoor unit that communicates based on a second voltage that is lower than the first voltage; A communication adapter, The communication adapter includes: A first communication unit that communicates with the outdoor unit based on the first voltage; a second communication unit that communicates with the indoor unit based on the second voltage, The second communication unit transmits communication data received by the first communication unit from the outdoor unit to the indoor unit based on the second voltage, The first communication unit transmits communication data received by the second communication unit from the indoor unit to the outdoor unit based on the first voltage, the outdoor unit and the communication adapter are connected by a communication line that passes a current supplied from a DC power supply provided in the outdoor unit to the communication adapter, and a shared line that passes the current that has passed through the communication line from the communication adapter to the outdoor unit; The first communication unit is a transmission circuit including a transmitting photocoupler whose conductive / non-conductive state is controlled in response to communication data to be transmitted to the outdoor unit, and which controls the conductive / non-conductive state of a transmission path including the communication line and the shared line in response to the conductive / non-conductive state of the transmitting photocoupler; a receiving photocoupler whose conductive / non-conductive state is controlled in response to the conductive / non-conductive state of the transmission path, and a receiving circuit that receives communication data transmitted from the outdoor unit by detecting the conductive / non-conductive state of the receiving photocoupler. Air conditioning system.

6. an indoor unit that communicates based on a first voltage; an outdoor unit that communicates based on a second voltage lower than the first voltage; A communication adapter, The communication adapter includes: A first communication unit that communicates with the indoor unit based on the first voltage; a second communication unit that communicates with the outdoor unit based on the second voltage, the second communication unit transmits communication data received by the first communication unit from the indoor unit to the outdoor unit based on the second voltage; The first communication unit transmits communication data received by the second communication unit from the outdoor unit to the indoor unit based on the first voltage, The indoor unit and the communication adapter are connected by a communication line that passes a current supplied from a DC power source provided in the communication adapter to the indoor unit, and a shared line that passes the current that has passed through the communication line from the indoor unit to the communication adapter, The first communication unit is a transmission circuit including a transmitting photocoupler whose conductive / non-conductive state is controlled according to communication data to be transmitted to the indoor unit, and which controls the conductive / non-conductive state of a transmission path including the communication line and the shared line according to the conductive / non-conductive state of the transmitting photocoupler; a receiving photocoupler whose conductive / non-conductive state is controlled in response to the conductive / non-conductive state of the transmission path, and a receiving circuit that receives communication data transmitted from the indoor unit by detecting the conductive / non-conductive state of the receiving photocoupler; Air conditioning system.