Air conditioning system

Abstract

A communication adaptor includes a high-voltage communicator that performs high-voltage communication with an outdoor device and a low-voltage communicator that performs low-voltage communication with a communication adaptor The low-voltage communicator transmits, to the communication adaptor by low-voltage communication, communication data received by the high-voltage communicator from the outdoor device The high-voltage communicator transmits, to the outdoor device by high-voltage communication, communication data received by the low-voltage communicator from the communication adaptor

Description

TECHNICAL FIELD

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

[0002] In air conditioning systems installed in an office building, a shop, or the like, a configuration is widely adopted in which an outdoor device and an indoor device are connected to each other with a three-core cable containing a power line, a signal line, and a common line (for example, Patent Literature 1). In this configuration, a high voltage (for example, 200 VAC) is applied between the power line and the common line that are connected to an external power supply, and power is supplied to the indoor device from the external power supply via the outdoor device.

[0003] Air conditioning systems are also known that include individual external power supplies corresponding to an outdoor device and an indoor device. In this configuration as well, communication between the outdoor device and the indoor device requires a common line, and a high voltage is applied to the common line.CITATION LISTPatent Literature

[0004] Patent Literature 1: Japanese Patent No. 6239143SUMMARY OF INVENTIONTechnical Problem

[0005] However, in markets such as North America, wiring between air conditioners (an outdoor device and an indoor device) is generally required to be low voltage (for example, 24 VAC). To use the air conditioning systems with the above configuration in such countries, there is a great possibility that installation costs will be high or that local contractors will refuse to perform installation work. This is one of factors preventing expansion of sales channels into these markets.

[0006] Thus, there are circumstances where proposals for a new technique that enables low-voltage wiring between air conditioners configured to communicate with each other with a high voltage are desired.

[0007] The present disclosure is made in view of the above circumstances, and an objective of the present disclosure is to provide a communication adaptor and an air conditioning system that enable low-voltage wiring between air conditioners configured to communicate with each other with a high voltage.Solution to Problem

[0008] In order to achieve the above objective, a communication adaptor according to the present disclosure includes;

[0009] a first communicator to communicate with an air conditioner based on a first voltage; and

[0010] a second communicator to communicate with a device different from the air conditioner based on a second voltage lower than the first voltage, wherein

[0011] the second communicator transmits, to the device, based on the second voltage, communication data received by the first communicator from the air conditioner, and

[0012] the first communicator transmits, to the air conditioner, based on the first voltage, communication data received by the second communicator from the device.Advantageous Effects of Invention

[0013] The present disclosure enables low-voltage wiring between air conditioners configured to communicate with each other with a high voltage.BRIEF DESCRIPTION OF DRAWINGS

[0014] FIG. 1 illustrates an overall configuration of an air conditioning system in Embodiment 1;

[0015] FIG. 2 is a block diagram illustrating a configuration of a controller included in an outdoor device in Embodiment 1;

[0016] FIG. 3 is a circuit diagram illustrating configurations of a high-voltage communicator and a communication adaptor of the outdoor device in Embodiment 1;

[0017] FIG. 4 illustrates an overall configuration of an air conditioning system in Embodiment 2;

[0018] FIG. 5 illustrates an overall configuration of an air conditioning system in Embodiment 3;

[0019] FIG. 6 is a timing chart illustrating operation of each of communicators at transmission of communication data from an outdoor device to an indoor device and at transmission of communication data from the indoor device to the outdoor device in Embodiment 3;

[0020] FIG. 7 illustrates an overall configuration of an air conditioning system in Embodiment 4; and

[0021] FIG. 8 illustrates an overall configuration of an air conditioning system in Embodiment 5.DESCRIPTION OF EMBODIMENTS

[0022] Embodiments of the present disclosure are described hereinafter in detail with reference to the drawings.Embodiment 1

[0023] FIG. 1 illustrates an overall configuration of an air conditioning system 1 in 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 performs air conditioning of, for example, a building such as an office building or a shop, and includes an outdoor unit 2 and an indoor unit 3. The air conditioning system 1 may include a plurality of indoor units 3. In the air conditioning system 1, an outdoor device 20 and an indoor device 30 are connected to each other via a non-illustrated refrigerant piping for circulation of refrigerant. A communication adaptor 21 of the outdoor unit 2 and a communication adaptor 31 of the indoor unit 3 are communicatively connected to each other with a cable containing two wires.Outdoor Unit 2

[0024] The outdoor unit 2 includes the outdoor device 20 and the communication adaptor 21. The communication adaptor 21 is disposed in the vicinity of the outdoor device 20. The communication adaptor 21 may be disposed in a housing of the outdoor device 20.Outdoor Device 20

[0025] The outdoor device 20 is an example of an air conditioner according to the present disclosure, and an example of an outdoor device according to the present disclosure. The outdoor device 20 includes a power supplier 200, a high-voltage communicator 201, and a controller 202. The outdoor device 20 also includes mechanisms required for air conditioning (hereinafter, referred to as the “outdoor device main unit”) such as a compressor, an outdoor heat exchanger, an outdoor fan, and an expansion valve, which are not illustrated in the drawings.

[0026] The power supplier 200 outputs power for driving the outdoor device 20 based on power input from an external power supply 4. That is, the power supplier 200 outputs, to each of the high-voltage communicator 201, the controller 202, and the outdoor device main unit, power required for operation thereof. The external power supply 4 is an alternating-current (AC) power supply that supplies AC power, and is a commercial power supply that outputs, for example, a voltage of 200 V. The extremal power supply 4 may be a power supply using, for example, a private power generator or a renewable energy.

[0027] Although details are described later, the high-voltage communicator 201 is a communication circuit for communication with another device based on a first voltage (for example, a ground voltage of 200 V), and includes electronic components, such as a transistor and a photocoupler, and a communication driver integrated circuit (IC). Hereinafter, communication based on the first voltage is referred to as the high-voltage communication.

[0028] The controller 202 performs overall control of the outdoor device 20. As illustrated in FIG. 2, the controller 202 includes a central processing unit (CPU) 220, a read-only memory (ROM) 221, a random-access memory (RAM) 222, an input / output (I / O) interface 223, and an auxiliary storage device 224. The controller 202 performs operation including generation of communication data (command data or notification data) for the indoor device 30, processing based on communication data received from the indoor device 30, and control of the outdoor device main unit. The command data is data indicating a command on another device, and the notification data is data to be notified to another device (for example, response data to command data received or the like).Communication Adaptor 21

[0029] Referring back to FIG. 1, the communication adaptor 21 is an example of a communication adaptor according to the present disclosure, and an example of an adaptor for the outdoor device according to the present disclosure. The communication adaptor 21 includes an insulating power supplier 210, a high-voltage communicator 211, a low-voltage communicator 212, and a controller 213. The insulating power supplier 210 is an example of an insulating power supplier according to the present disclosure. The insulating power supplier 210 is a power supply circuit in which input and output are electrically insulated from each other by reinforced insulation, and outputs power for driving the communication adaptor 21 based on power input from the external power supply 4 via the outdoor device 20. That is, the insulating power supplier 210 outputs, to each of the high-voltage communicator 211, the low-voltage communicator 212, and the controller 213, power required for operation thereof.

[0030] The high-voltage communicator 211 is an example of a first communicator according to the present disclosure. Although details are described later, the high-voltage communicator 211 is a communication circuit for high-voltage communication with another device, and includes electronic components, such as a transistor and a photocoupler, and a communication driver IC.

[0031] The low-voltage communicator 212 is an example of a second communicator according to the present disclosure. The low-voltage communicator 212 is a communication circuit for communication with another device based on a second voltage lower than the first voltage (for example, a ground voltage of 5V), and includes electronic components, such as a transistor and a photocoupler, and a communication driver IC. Hereinafter, communication based on the second voltage is referred to as the low-voltage communication. A communication protocol of the low-voltage communication is, for example, single-ended transmission such as RS232C, differential transmission such as RS-485 or a controller area network (CAN), Ethernet (registered trademark), or the like. A. connection interface on the indoor unit 3 side of the low-voltage communicator 212 has reinforced insulation or double insulation to the external power supply 4.

[0032] The controller 213 includes a CPU, a ROM, and a RAM, none of which are illustrated in the drawings, and performs overall control of the communication adaptor 21. The controller 213 performs processing including transmission, to the indoor unit 3 via the low-voltage communicator 212, of communication data received by the high-voltage communicator 211 from the outdoor device 20, and transmission, to the outdoor device 20 via the high-voltage communicator 211, of communication data received by the low-voltage communicator 212 from the indoor unit 3.Indoor Unit 3

[0033] The indoor unit 3 includes the indoor device 30 and the communication adaptor 31. The communication adaptor 31 is disposed in the vicinity of the indoor device 30. The communication adaptor 31 may be disposed in a housing of the indoor device 30.Indoor Device 30

[0034] The indoor device 30 is an example of the air conditioner according to the present disclosure, and an example of an indoor device according to the present disclosure. The indoor device 30 includes a power supplier 300, a high-voltage communicator 301, and a controller 302. The indoor device 30 also includes mechanisms required for air conditioning (hereinafter, referred to as the “indoor device main unit”) such as an indoor heat exchanger, an electromagnetic valve, and an indoor fan, which are not illustrated in the drawings.

[0035] The power supplier 300 outputs power for driving the indoor device 30 based on power input from an external power supply 5. That is, the power supplier 300 outputs, to each of the high-voltage communicator 301, the controller 302, and the indoor device main unit, power required for operation thereof. The external power supply 5 is, for example, a commercial power supply that is supplied from a power company. The external power supply 5 may be a power supply using, for example, a private power generator or a renewable energy.

[0036] Although details are described later, the high-voltage communicator 301 is a communication circuit for high-voltage communication with another device, and includes electronic components, such as a transistor and a photocoupler, and a communication driver IC. As with the controller 202 of the outdoor device 20 (refer to FIG. 2), the controller 302 includes a CPU, a ROM, a RAM, an I / O interface, and an auxiliary storage device, and performs overall control of the indoor device 30. The controller 302 performs operation including generation of communication data (command data or notification data) for the outdoor device 20, processing based on communication data received from the outdoor device 20, and control of the indoor device main unit.Communication Adaptor 31

[0037] The communication adaptor 31 is an example of the communication adaptor according to the present disclosure, and an example of an adaptor for the indoor device according to the present disclosure. The communication adaptor 31 includes an insulating power supplier 310, a high-voltage communicator 311, a low-voltage communicator 312, and a controller 313. The insulating power supplier 310 is an example of the insulating power supplier according to the present disclosure. The insulating power supplier 310 is a power supply circuit in which input and output are electrically insulated from each other by reinforced insulation, and outputs power for driving the communication adaptor 31 based on power input from the external power supply 5 via the indoor device 30. That is, the insulating power supplier 310 supplies, to each of the high-voltage communicator 311, the low-voltage communicator 312, and the controller 313, power required for operation thereof.

[0038] The high-voltage communicator 311 is an example of the first communicator according to the present disclosure, and an example of a third communicator according to the present disclosure. Although details are described later, the high-voltage communicator 311 is a communication circuit for high-voltage communication with another device, and includes electronic components, such as a transistor and a photocoupler, and a communication driver IC.

[0039] The low-voltage communicator 312 is an example of the second communicator according to the present disclosure, and an example of a fourth communicator according to the present disclosure. The low-voltage communicator 312 is a communication circuit for low-voltage communication with another device, and includes electronic components, such as a transistor and a photocoupler, and a communication driver IC. A connection interface on the outdoor unit 2 side of the low-voltage communicator 312 has reinforced insulation or double insulation to the external power supply 5.

[0040] The controller 313 includes a CPU, a ROM, and a RAM, none of which are illustrated in the drawings, and performs overall control of the communication adaptor 31. The controller 313 performs processing including transmission, to the outdoor unit 2 via the low-voltage communicator 312, of communication data that the high-voltage communicator 311 has received from the indoor device 30, and transmission, to the indoor device 30 via the high-voltage communicator 311, of communication data that the low-voltage communicator 312 has received from the outdoor unit 2.High-Voltage Communication

[0041] High-voltage communications in the present embodiment, that is, high-voltage communication between the outdoor device 20 and the communication adaptor 21 and high-voltage communication between the indoor device 30 and the communication adaptor 31 are described below in detail. FIG. 3 is a circuit diagram illustrating a configuration of the high-voltage communicator 201 of the outdoor device 20 in the outdoor unit 2 and a configuration of the high-voltage communicator 211 of the communication adaptor 21 in the outdoor unit 2. A configuration of the high-voltage communicator 301 of the indoor device 30 in the indoor unit 3 is the same as the configuration of the high-voltage communicator 211 illustrated in FIG. 3, and a configuration of the high-voltage communicator 311 of the communication adaptor 31 in the indoor unit 3 is the same as the configuration of the high-voltage communicator 201 illustrated in FIG. 3.High-Voltage Communicator 201

[0042] As illustrated in FIG. 3, the high-voltage communicator 201 includes a direct-current (DC) power supply 400, a transmission circuit 420, a reception circuit 440, a communication driver IC 460, and a diode 470. The DC power supply 400 is a DC power supply that supplies a communication current for use 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 of Vc (V) based on a potential of a common line 6. The DC power supply 400 is a half-wave rectification circuit that includes a resistor 401, a diode 402, a constant-voltage diode 403, and an electrolytic capacitor 404.

[0043] The resistor 401 is a resistor for generation of a DC voltage. A first end of the resistor 401 is connected to the external power supply 4 via a power line 7. A second end of the resistor 401 is connected to an anode of the diode 402. The diode 402 is a rectification element that feeds a current solely in a direction from the anode toward a cathode. The cathode of the diode 402 is connected to a cathode of the constant-voltage diode 403, a positive terminal of the electrolytic capacitor 404, and an emitter of a positive negative positive (PNP) transistor 422, a first end of a resistor 423, and a collector of a phototransistor 432 of a photocoupler 430 in the transmission circuit 420.

[0044] The constant-voltage diode 403 is a diode that allows little reverse current flow when a reverse voltage applied between an anode and the cathode is lower than a breakdown voltage, and allows a rapid reverse current flow when the reverse voltage is higher than or equal to the breakdown voltage. The voltage (breakdown voltage) of both ends of the constant-voltage diode 403 is assumed to be Vc (V). The anode of the constant-voltage diode 403 is connected to a negative terminal of the electrolytic capacitor 404 and a cathode of a diode 426 of the transmission circuit 420. The electrolytic capacitor 404 is a capacitor that temporarily stores an energy supplied and has a polarity.

[0045] The transmission circuit 420 is a circuit that transmits communication data by controlling a communication current flowing through a transmission path (that is, through the high-voltage communicator 201, a communication line 8, the high-voltage communicator 211, the common line 6, and the high-voltage communicator 201 in this order). Specifically, the transmission circuit 420 does not feed a communication current to the transmission path while the level of a parallel output (PO) terminal of the communication driver IC 460 is an H level, and feeds a communication current to the transmission path while the level of the PO terminal of the communication driver IC 460 is an L level. For example, the H level is 5V and the L level is OV. The transmission circuit 420 includes PNP transistors 421 and 422, resistors 423 to 425, the diode 426, a ground terminal 427, and the photocoupler 430.

[0046] The PNP transistor 421 is a switching element of which a current path (a path between an emitter and a collector) is disposed on the transmission path. The PNP transistor 421 is controlled to be in a conductive / non-conductive state opposite to that of the phototransistor 432 of the photocoupler 430. The emitter of the PNP transistor 421 is connected to a base of the PNP transistor 422 and a second end of the resistor 423. The collector of the PNP transistor 421 is connected to a first end of the resistor 444 and an anode of a light-emitting diode 451 of a photocoupler 450 in the reception circuit 440. A base of the PNP transistor 421 is connected to a collector of the PNP transistor 422, a first end of the resistor 424, and an emitter of the phototransistor 432.

[0047] The PNP transistor 422, together with the resistor 423, limits an upper limit of a communication current flowing through the transmission path. The resistor 423 is a current limitation resistor that is disposed on the transmission path. When the voltage between the emitter and the base of the PNP transistor 422 (the voltage of both ends of the resistor 423) exceeds a saturation voltage (for example, 0.6V) due to a communication current supplied from the DC power supply 400, the PNP transistor 422 is turned to an ON state. Then, a current flows through the resistor 424 and is less likely to flow through the current path of the PNP transistor 421. That is, the upper limit of a communication current flowing through the communication line 8 connecting the high-voltage communicator 201 of the outdoor device 20 and the high-voltage communicator 211 of the communication adaptor 21 is limited by a resistance value of the resistor 423. As described above, the PNP transistor 422 and the resistor 423 protect circuit elements (for example, the PNP transistor 421 and the photocoupler 450) of the high-voltage communicator 201.

[0048] The resistor 424 is a base resistor that limits a base current flowing through the PNP transistor 421. The resistor 424 is also a load resistor that limits a current flowing through the phototransistor 432. The resistor 425 is a resistor that limits a current flowing through the light-emitting diode 431 of the photocoupler 430. A first end of the resistor 425 is connected to an anode of the light-emitting diode 431, and a second end of the resistor 425 is connected to the PO terminal of the communication driver IC 460. The diode 426 is a rectification element that feeds a current solely in a direction from an anode toward the cathode. The ground terminal 427 is a terminal that is grounded, and a terminal to which a ground potential is applied

[0049] The photocoupler 430 is an element for mutual electrical insulation of two circuits. The photocoupler 430 includes the light-emitting diode 431 and the phototransistor 432. In the photocoupler 430, when a primary current flows through the light-emitting diode 431, a secondary current flows through a current path of the phototransistor 432. Hereafter, as appropriate, a current flowing through the light-emitting diode 431 is referred to as the primary current, and a current flowing through the current path of the phototransistor 432 is referred to as the secondary current. In addition, a voltage applied between the anode of the light-emitting diode 431 and a cathode of the light-emitting diode 431 is referred to as the primary voltage, and a voltage applied between the emitter and the collector of the phototransistor 432 is referred to as the secondary voltage.

[0050] When a voltage value of the primary voltage is greater than or equal to a threshold, the light-emitting diode 431 feeds the primary current and emits light having intensity corresponding to a current value of the primary current. The cathode of the light-emitting diode 431 is connected to the ground terminal 427. The phototransistor 432 feeds, from the collector toward the emitter, the secondary current corresponding to the secondary voltage and the intensity of the light emitted by the light-emitting diode 431.

[0051] Operation of the transmission circuit 420 is described below. When the PO terminal of the communication driver IC 460 is the H level, a current flows through the light-emitting diode 431 via the resistor 425. Thus, the photocoupler 430 is turned to the ON state, and a current supplied from the DC power supply 400 flows through the common line 6 via the phototransistor 432, the resistor 424, and the diode 426. The voltage between the emitter and the collector of the phototransistor 432 in the ON state does not exceed a saturation voltage between the emitter and the base of the PNP transistor 421 (for example, about 0.6V). Thus, the PNP transistor 421 is turned to an OFF state, and no communication current flows through the transmission path.

[0052] When the PO terminal of the communication driver IC 460 is the L level, no current flows through the light-emitting diode 431. Thus, the photocoupler 430 is turned to the OFF state, and the base current of the PNP transistor 421 flows through the common line 6 via the resistor 424 and the diode 426. As a result, the PNP transistor 421 is turned to the ON state, and a communication current flows through the transmission path.

[0053] The reception circuit 440 is a circuit that receives communication data by monitoring a communication current flowing through the transmission path. Specifically, the reception circuit 440 sets a parallel input (PI) terminal of the communication driver IC 460 to the H level while the communication current flows through the transmission path, and sets the PI terminal of the communication driver IC 460 to the L level while no communication current flows through the transmission path. The reception circuit 440 includes a negative positive negative (NPN) transistor 441, resistors 442 to 444, a power supply terminal 445, ground terminals 446 and 447, and the photocoupler 450.

[0054] The NPN transistor 441 is provided to reduce a turn-off time of the photocoupler 450. An emitter of the NPN transistor 441 is connected to the ground terminal 446. A collector of the NPN transistor 441 is connected to a first end of the resistor 442 and the PI terminal of the communication driver IC 460. A base of the NPN transistor 441 is connected to a first end of the resistor 443 and a collector of a phototransistor 452 of the photocoupler 450. The resistor 442 is a resistor for pull-up of the PI terminal of the communication driver IC 460 to the H level. A second end of the resistor 442 is connected to a second end of the resistor 443 and the power supply terminal 445.

[0055] The resistor 443 is a base resistor that limits a base current of the NPN transistor 441. The resistor 443 is also a load resistor that limits a current flowing through the phototransistor 452. The power supply terminal 445 is a terminal that is connected to the power supplier 200. The potential of the power supply terminal 445 is the H level (for example, 5V). The ground terminals 446 and 447 are terminals that are grounded, and terminals to which ground potentials are applied. The ground terminals 446 and 447 can be considered as being connected to each other.

[0056] The resistor 444 is a threshold resistor of the light-emitting diode 451. That is, when a communication current is minute and the voltage between both ends of the resistor 444 is lower than a forward voltage of the light-emitting diode 451, all of the communication current flows through the resistor 444 and none of the communication current flows through the light-emitting diode 451. In contrast, when a communication current is large and the voltage between both ends of the resistor 444 is higher than or equal to the forward voltage of the light-emitting diode 451, the communication current flows through the light-emitting diode 451 as well. A second end of the resistor 444 is connected to a cathode of the light-emitting diode 451 and an anode of the diode 470.

[0057] The photocoupler 450 basically has the same configuration as the photocoupler 430. The photocoupler 450 includes the light-emitting diode 451 and the phototransistor 452. In the photocoupler 450, when the primary current flows through the light-emitting diode 451, the secondary current flows through a current path of the phototransistor 452.

[0058] Operation of the reception circuit 440 is described below. When a communication current flows through the transmission path, a current flows through the light-emitting diode 451, and the photocoupler 450 is turned to the ON state. Thus, a current flows through the ground terminal 447 from the power supply terminal 445 via the resistor 443 and the phototransistor 452. As a result, the NPN transistor 441 is turned to the OFF state, no current flows through the resistor 442, and the PI terminal of the communication driver IC 460 is set to the H level.

[0059] When no communication current flows through the transmission path, no current flows through the light-emitting diode 451, and the photocoupler 450 is turned to the OFF state. Thus, no current flows through the phototransistor 452, and the NPN transistor 441 is turned to the ON state. As a result, a current flows through the resistor 442, and the PI terminal of the communication driver IC 460 is set to the L level. When a photocoupler 510 of the communication adaptor 211 is in the ON state, a minute communication current flows through the transmission path. However, when a communication current flowing through the transmission path is minute, a voltage drop in the resistor 444 is small and no current flows through the light-emitting diode 451. That is, when a communication current is minute, the photocoupler 450 is turned to the OFF state. Hereinafter, a case where a communication current is minute is considered to be the same as a case where no communication current flows.

[0060] The communication driver IC 460 controls the photocoupler 430 of the transmission circuit 420 to transmit communication data. The communication driver IC 460 receives communication data based on a status of the photocoupler 450 of the reception circuit 440. The communication driver IC 460 includes the PO terminal that outputs a voltage at the H level or the L level, and the PI terminal that inputs a voltage at the H level or the L level. The communication driver IC 460 switches a level of a voltage to be applied to the PO terminal between the H level and the L level in accordance with the communication data to be transmitted. The communication driver IC 460 determines which of the H level and the L level a voltage applied to the PI terminal is. The communication driver IC 460 may include a digital input / output port.

[0061] The diode 470 is a rectification element that feeds a current solely in a direction from the anode toward a cathode. The diode 470 blocks a reverse current that may flow through the transmission path due to wiring errors or the like. The cathode of the diode 470 is connected to an anode of a diode 541 of the high-voltage communicator 211High-Voltage Communicator 211

[0062] The high-voltage communicator 211 of the communication adaptor 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 is a circuit that transmits communication data by controlling a communication current flowing through the transmission path. Specifically, the transmission circuit 500 does not feed a communication current to the transmission path while the level of a PO terminal of the communication driver IC 540 is the H level, and feeds a communication current to the transmission path while the level of the PO terminal of the communication driver IC 540 is the L level. The transmission circuit 500 includes a PNP transistor 501, resistors 502 to 504, a ground terminal 505, and the photocoupler 510.

[0063] The PNP transistor 501 is a switching element of which a current path is disposed on the transmission path. The PNP transistor 501 is controlled to be in a conductive / non-conductive state opposite to that of a phototransistor 512 of the photocoupler 510. An emitter of the PNP transistor 501 is connected to a collector of the phototransistor 512 and a cathode of the diode 541. A collector of the PNP transistor 501 is connected to a first end of the resistor 502. A base of the PNP transistor 501 is connected to a first end of the resistor 503 and an emitter of the phototransistor 512.

[0064] The resistor 502 is a resistor that limits a communication current flowing through the transmission path. A second end of the resistor 502 is connected to an anode of a light-emitting diode 531 of a photocoupler 530 in the reception circuit 520. The resistor 503 is a base resistor that limits a base current flowing through the PNP transistor 501. The resistor 503 is also a load resistor that limits a current flowing through the phototransistor 512. The resistance value of the resistor 503 is sufficiently larger than the resistance value of the resistor 502. Thus, the current value of a communication current flowing via the resistor 503 when the photocoupler 510 is in the ON state is sufficiently smaller than the current value of a communication current flowing via the resistor 502 when the photocoupler 510 is in the OFF state.

[0065] In this configuration, the photocoupler 450 of the high-voltage communicator 201 is turned to the OFF state when the photocoupler 510 is turned to the ON state, and the photocoupler 450 is turned to the ON state when the photocoupler 510 is turned to the OFF state. A second end of the resistor 503 is connected to a cathode of the light-emitting diode 531 and an anode of the constant-voltage diode 542.

[0066] The resistor 504 is a resistor that limits a current flowing through the light-emitting diode 511 of the photocoupler 510. That is, the resistor 504 protects circuit elements (for example, the PNP transistor 501 and the photocoupler 530) of the high-voltage communicator 211. A first end of the resistor 504 is connected to an anode of the light-emitting diode 511. A second 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 a terminal to which a ground potential is applied. The ground terminal 505 is connected to a cathode of the light-emitting diode 511.

[0067] The photocoupler 510 basically has the same configuration as the photocoupler 430 in the transmission circuit 420 of the high-voltage communicator 201. The photocoupler 510 includes the light-emitting diode 511 and the phototransistor 512. In the photocoupler 510, when the primary current flows through the light-emitting diode 511, the secondary current flows through a current path of the phototransistor 512.

[0068] Operation of the transmission circuit 500 is described below. When the PO terminal of the communication driver IC 540 is the H level, a current flows through the light-emitting diode 511 via the resistor 504. Thus, the photocoupler 510 is turned to the ON state, and a communication current supplied from the communication line 8 flows through the common line 6 via the phototransistor 512 and the resistor 503. However, the resistance value of the resistor 503 is large and the communication current flowing therethrough is thus small. The voltage between the emitter and the collector of the phototransistor 512 in the ON state does not exceed a saturation voltage between the emitter and the base of the PNP transistor 501 (for example, about 0.6V). Thus, the PNP transistor 501 is turned to the OFF state, and little communication current flows through the transmission path.

[0069] When the PO terminal of the communication driver IC 540 is the L level, no current flows through the light-emitting diode 511. Thus, the photocoupler 510 is turned to the OFF state, and the base current of the PNP transistor 501 flows through the common line 6 via the resistor 503. This turns the PNP transistor 501 to the ON state, and causes a communication current to flow through the transmission path.

[0070] The reception circuit 520 is a circuit that receives communication data by monitoring a communication current flowing through the transmission path. Specifically, the reception circuit 520 sets a PI terminal of the communication driver IC 540 to the H level while a communication current flows through the transmission path, and sets the PI terminal of the communication driver IC 540 to the L level while no communication current flows through the transmission path. The reception circuit 520 includes a NPN transistor 521, resistors 522 and 523, a power supply terminal 524, ground terminals 525 and 526, and the photocoupler 530.

[0071] The NPN transistor 521 is provided to reduce a turn-off time of the photocoupler 530. An emitter of the NPN transistor 521 is connected to the ground terminal 525. A collector of the NPN transistor 521 is connected to a first end of the resistor 522 and the PI terminal of the communication driver IC 540. A base of the NPN transistor 521 is connected to a first end of the resistor 523 and a collector of a phototransistor 532 of the photocoupler 530. The resistor 522 is a resistor for pull-up of the PI terminal of the communication driver IC 540 to the H level. A second end of the resistor 522 is connected to a second end of the resistor 523 and the power supply terminal 524.

[0072] The resistor 523 is a base resistor that limits a base current of the NPN transistor 521. The resistor 523 is also a load resistor that limits a current flowing through the phototransistor 532. The power supply terminal 524 is a terminal that is connected to the insulating power supplier 210. The potential of the power supply terminal 524 is the H level. The ground terminals 525 and 526 are terminals that are grounded, and terminals to which ground potentials are applied. The ground terminals 525 and 526 can be considered as being connected to each other.

[0073] The photocoupler 530 basically has the same configuration as the photocoupler 450 in the reception circuit 440 of the high-voltage communicator 201. The photocoupler 530 includes the light-emitting diode 531 and the phototransistor 532. In the photocoupler 530, when the primary current flows through the light-emitting diode 531. the secondary current flows through a current path of the phototransistor 532.

[0074] Operation of the reception circuit 520 is described below. When a communication current flows through the transmission path, a current flows through the light-emitting diode 531, and the photocoupler 530 is turned to the ON state. Thus, a current flows through the ground terminal 526 from the power supply terminal 524 via the resistor 523 and the phototransistor 532. As a result, the NPN transistor 521 is turned to the OFF state, no current flows through the resistor 522, and the PI terminal of the communication driver IC 540 is set to the H level.

[0075] When no communication current flows through the transmission path, no current flows through the light-emitting diode 531, and the photocoupler 530 is turned to the OFF state. Thus, no current flows through the phototransistor 532, and the NPN transistor 521 is turned to the ON state. As a result, a current flows through the resistor 522, and the PI terminal of the communication driver IC 540 is set to the L level.

[0076] The communication driver IC 540 controls the photocoupler 510 of the transmission circuit 500 to transmit communication data. The communication driver IC 540 receives communication data based on a status of the photocoupler 530 of the reception circuit 520. The communication driver IC 540 includes the PO terminal that outputs a voltage at the H level or the L level, and the PI terminal that inputs a voltage at the H level or the L level. The communication driver IC 540 switches a level of a voltage to be applied to the PO terminal between the H level and the L level in accordance with data to be transmitted. The communication driver IC 540 determines which of the H level and the L level a voltage applied to the PI terminal is. The communication driver IC 540 may include a digital input / output port.

[0077] The diode 541 is a rectification element that feeds a current solely in a direction from the anode toward the cathode. The diode 541 blocks a reverse current that may flow through the transmission path due to wiring errors or the like. The constant-voltage diode 542 is a diode that allows little reverse current flow when a reverse voltage applied between the anode and a cathode is lower than a breakdown voltage, and allows a rapid reverse current flow when the reverse voltage is higher than or equal to the breakdown voltage. The constant-voltage diode 542 protects circuit elements (for example, the PNP transistor 501, the photocoupler 510, and the photocoupler 530) of the high-voltage communicator 211.Operation of Air Conditioning System 1

[0078] Next, operation relating to transmission and reception of communication data in the air conditioning system 1 is described.

[0079] Transmission of Communication Data from Outdoor Device 20 to Indoor Device 30

[0080] (1) The outdoor device 20 of the outdoor unit 2 transmits communication data to the communication adaptor 21 by high-voltage communication. The communication data contains information indicating a transmission source and a transmission destination.

[0081] (2) The communication adaptor 21 receives the communication data from the outdoor device 20 by high-voltage communication.

[0082] (3) The communication adaptor 21 transmits, to the communication adaptor 31 of the indoor unit 3 by low-voltage communication, the communication data received from the outdoor device 20.

[0083] (4) The communication adaptor 31 of the indoor unit 3 receives the communication data from the communication adaptor 21 of the outdoor unit 2 by low-voltage communication.

[0084] (5) The communication adaptor 31 transmits, to the indoor device 30 by high-voltage communication, the communication data received from the outdoor unit 2.

[0085] (6) The indoor device 30 receives the communication data from the communication adaptor 31 by high-voltage communication.

[0086] (7) The indoor device 30 analyzes the received communication data and executes processing based on this communication data.Transmission of Communication Data from Indoor Device 30 to Outdoor Device 20(1) The indoor device 30 of the indoor unit 3 transmits communication data to the communication adaptor 31 by high-voltage communication. The communication data contains information indicating a transmission source and a transmission destination.

[0088] (2) The communication adaptor 31 receives the communication data from the indoor device 30 by high-voltage communication.

[0089] (3) The communication adaptor 31 transmits, to the communication adaptor 21 of the outdoor unit 2 by low-voltage communication, the communication data received from the indoor device 30.

[0090] (4) The communication adaptor 21 of the outdoor unit 2 receives the communication data from the communication adaptor 31 of the indoor unit 3 by low-voltage communication.

[0091] (5) The communication adaptor 21 transmits, to the outdoor device 20 by high-voltage communication, the communication data received from the indoor unit 3.

[0092] (6) The outdoor device 20 receives the communication data from the communication adaptor 21 by high-voltage communication.

[0093] (7) The outdoor device 20 analyzes the received communication data and executes processing based on this communication data.

[0094] As described above, the air conditioning system 1 in the present embodiment includes the communication adaptor 21 that performs high-voltage communication with the outdoor device 20 and low-voltage communication with a device different from the outdoor device 20, and the communication adaptor 31 that performs high-voltage communication with the indoor device 30 and low-voltage communication with a device different from the indoor device 30. Thus, by connecting the outdoor device 20 and the communication adaptor 21 to each other and connecting the indoor device 30 and the communication adaptor 31 to each other at shipping from a factory, high-voltage wiring work on site is unnecessary. As a result, expansion of sales channels into markets that require low-voltage wiring between air conditioners can be expected.

[0095] In the communication adaptor 21, although power is input to the insulating power supplier 210 from the external power supply 4, input and output are electrically insulated from each other by reinforced insulation. Further, the connection interface on the indoor unit 3 side of the low-voltage communicator 212 has reinforced insulation or double insulation to the external power supply 4. Similarly, in the communication adaptor 31, although power is input to the insulating power supplier 310 from the external power supply 5, input and output are electrically insulated from each other by reinforced insulation. Further, the connection interface on the outdoor unit 2 side of the low-voltage communicator312 has reinforced insulation or double insulation to the external power supply 5. As a result, expansion of sales channels into the above markets is further promoted.Embodiment 2

[0096] Next, Embodiment 2 of the present disclosure is described. In the following description, components that are in common with Embodiment 1 are assigned the same reference signs, and description of these components is omitted.

[0097] FIG. 4 illustrates an overall configuration of an air conditioning system 1A in Embodiment 2. The air conditioning system 1A is an example of the air conditioning system according to the present disclosure. The air-conditioning system 1A is a system that performs air conditioning of, for example, a building such as an office building or a shop, and includes an outdoor unit 2A and an indoor unit 3A. The air conditioning system LA may include a plurality of indoor units 3A.Outdoor Unit 2A

[0098] The outdoor unit 2A includes an outdoor device 20A and a communication adaptor 21A. The communication adaptor 21A is disposed in the vicinity of the outdoor device 20A. The communication adaptor 21A may be disposed in a housing of the outdoor device 20A.Outdoor Device 20A

[0099] The outdoor device 20A is an example of the air conditioner according to the present disclosure, and an example of the outdoor device according to the present disclosure. As with the outdoor device 20 in Embodiment 1, the outdoor device 20A includes the power supplier 200, the high-voltage communicator 201, the controller 202, and the non-illustrated outdoor device main unit. The outdoor device 20A is different from the outdoor device 20 in that the outdoor device 20A is configured to supply power from the power supplier 200 to the insulating power supplier 210 of the communication adaptor 21A. In the other points, the configuration of the outdoor device 20A is the same as that of the outdoor device 20.Communication Adaptor 21A

[0100] The communication adaptor 21A is an example of the communication adaptor according to the present disclosure, and an example of the adaptor for the outdoor device according to the present disclosure. As with the communication adaptor 21 in Embodiment 1, the communication adaptor 21A includes the insulating power supplier 210, the high-voltage communicator 211, the low-voltage communicator 212, and the controller 213. The communication adaptor 21A is different from the communication adaptor 21 in that the communication adaptor 21A is configured to input power from the power supplier 200 of the outdoor device 20A, instead of the external power supply 4, to the insulating power supplier 210. In the other points, the configuration of the communication adaptor 21A is the same as that of the communication adaptor 21.Indoor Unit 3A

[0101] The indoor unit 3A includes an indoor device 30A and a communication adaptor 31A. The communication adaptor 31A is disposed in the vicinity of the indoor device 30A. The communication adaptor 31A may be disposed in a housing of the indoor device 30A.Indoor Device 30A

[0102] The indoor device 30A is an example of the air conditioner according to the present disclosure, and an example of the indoor device according to the present disclosure. As with the indoor device 30 in Embodiment 1, the indoor device 30A includes the power supplier 300, the high-voltage communicator 301, the controller 302, and the non-illustrated indoor device main unit. The indoor device 30A is different from the indoor device 30 in that the indoor device 30A is configured to supply power from the power supplier 300 to the insulating power supplier 310 of the communication adaptor 31A. In the other points, the configuration of the indoor device 30A is the same as that of the indoor device 30.Communication Adaptor 31A

[0103] The communication adaptor 31A is an example of the communication adaptor according to the present disclosure, and an example of the adaptor for the indoor device according to the present disclosure. As with the communication adaptor 31 in Embodiment 1, the communication adaptor 31A includes the insulating power supplier 310, the high-voltage communicator 311, the low-voltage communicator 312, and the controller 313. The communication adaptor 31A is different from the communication adaptor 31 in that the communication adaptor 31A is configured to input power from the power supplier 300 of the indoor device 30A, instead of the external power supply 5, to the insulating power supplier 310. In the other points, the configuration of the communication adaptor 31A is the same as that of the communication adaptor 31.

[0104] As described above, the air conditioning system 1A in the present embodiment includes the communication adaptor 21A that performs high-voltage communication with the outdoor device 20A and low-voltage communication with a device different from the outdoor device 20A, and the communication adaptor 31A that performs high-voltage communication with the indoor device 30A and low-voltage communication with a device different from the indoor device 30A. Thus, by connecting the outdoor device 20A and the communication adaptor 21A to each other and connecting the indoor device 30A and the communication adaptor 31A to each other at shipping from a factory, high-voltage wiring work on site is unnecessary. As a result, expansion of sales channels into markets that require low-voltage wiring between air conditioners can be expected.

[0105] In the communication adaptor 21A, although power is input to the insulating power supplier 210 from the power supply 200 of the outdoor device 20, input and output are electrically insulated from each other by reinforced insulation. Further, the connection interface on the indoor unit 3A side of the low-voltage communicator 212 has reinforced insulation or double insulation to the external power supply 4. Similarly, in the communication adaptor 31A, although power is input to the insulating power supplier 310 from the power supply 300 of the indoor device 30A, input and output are electrically insulated from each other by reinforced insulation. Further, the connection interface on the outdoor unit 2A side of the low-voltage communicator 312 has reinforced insulation or double insulation to the external power supply 5. As a result, expansion of sales channels into the above markets is further promoted.

[0106] The voltage output from the power supplier 200 of the outdoor device 20A is lower than the voltage output from the extemal power supply 4. This allows the insulating power supplier 210 to be smaller in the communication adaptor 21A. Similarly, the voltage output from the power supplier 300 of the indoor device 30A is lower than the voltage output from the extemal power supply 5. This allows the insulating power supplier 310 to be smaller in the communication adaptor 31A.Embodiment 3

[0107] Next, Embodiment 3 of the present disclosure is described. In the following description, components that are in common with Embodiment 1 are assigned the same reference signs, and description of these components is omitted.

[0108] FIG. 5 illustrates an overall configuration of an air conditioning system 1B in Embodiment 3. The air conditioning system 1B is an example of the air conditioning system according to the present disclosure. The air-conditioning system 1B is a system that performs air conditioning of, for example, a building such as an office building or a shop, and includes an outdoor unit 2B and an indoor unit 3B. The air conditioning system IB may include a plurality of indoor units 3B.Outdoor Unit 2B

[0109] The outdoor unit 2B includes the outdoor device 20 and a communication adaptor 21B. The communication adaptor 21B is disposed in the vicinity of the outdoor device 20. The communication adaptor 21B may be disposed in the housing of the outdoor device 20.Communication Adaptor 21B

[0110] The communication adaptor 21B is an example of the communication adaptor according to the present disclosure, and an example of the adaptor for the outdoor device according to the present disclosure. The communication adaptor 21B includes the insulating power supplier 210, the high-voltage communicator 211, and a low-voltage communicator 212A. The low-voltage communicator 212A is an example of the second communicator according to the present disclosure. As with the low-voltage communicator 212 in Embodiment 1, the low-voltage communicator 212A is a communication circuit for low-voltage communication with another device, and includes electronic components, such as a transistor and a photocoupler, and a communication driver IC.

[0111] The low-voltage communicator 212A communicates with another device by a full duplex communication (for example, four-wire RS-485). Between the high-voltage communicator 211 and the low-voltage communicator 212A, a transmission signal line and a reception signal line are cross-connected so as to be interchanged with each other. As with Embodiment 1, a connection interface on the indoor unit 3B side of the low-voltage communicator 212A has reinforced insulation or double insulation to the external power supply 4.Indoor Unit 3B

[0112] The indoor unit 3B includes the indoor device 30 and a communication adaptor 31B. The communication adaptor 31B is disposed in the vicinity of the indoor device 30. The communication adaptor 31B may be disposed in the housing of the indoor device 30.Communication Adaptor 31B

[0113] The communication adaptor 31B is an example of the communication adaptor according to the present disclosure, and an example of the adaptor for the indoor device according to the present disclosure. The communication adaptor 31B includes the insulating power supplier 310, the high-voltage communicator 311, and a low-voltage communicator 312A. The low-voltage communicator 312A is an example of the second communicator according to the present disclosure, and an example of the fourth communicator according to the present disclosure. As with the low-voltage communicator 312 in Embodiment 1, the low-voltage communicator 312A is a communication circuit for low-voltage communication with another device, and includes electronic components, such as a transistor and a photocoupler, and a communication driver IC.

[0114] The low-voltage communicator 312A communicates with another device by a full duplex communication (for example, four-wire RS-485). Between the high-voltage communicator 311 and the low-voltage communicator 312A, a transmission signal line and a reception signal line are cross-connected so as to be interchanged with each other. As with Embodiment 1, a connection interface on the outdoor unit 2B side of the low-voltage communicator 312A has reinforced insulation or double insulation to the external power supply 5.

[0115] FIG. 6 is a timing chart illustrating operation of each of the communicators (the high-voltage communicator 201, the high-voltage communicator 211, the low-voltage communicator 212A, the high-voltage communicator 301, the high-voltage communicator 311, and the low-voltage communicator 312A) at transmission of communication data from the outdoor device 20 to the indoor device 30 and at transmission of communication data from the indoor device 30 to the outdoor device 20 in the air conditioning system 1B. In FIG. 6, the ON state of a high-voltage communicator indicates a state in which the transmission path is conductive, that is, a state in which a communication current flows through the transmission path, and the OFF state of a high-voltage communicator indicates a state in which the transmission path is not conductive, that is, no communication current flows through the transmission path.

[0116] As described above, the air conditioning system 1B in the present embodiment includes the communication adaptor 21B that performs high-voltage communication with the outdoor device 20 and low-voltage communication with a device different from the outdoor device 20, and the communication adaptor 31B that performs high-voltage communication with the indoor device 30 and low-voltage communication with a device different from the indoor device 30. Thus, by connecting the outdoor device 20 and the communication adaptor 21B to each other and connecting the indoor device 30 and the communication adaptor 31B to each other at shipping from a factory, high-voltage wiring work on site is unnecessary, As a result, expansion of sales channels into markets that require low-voltage wiring between air conditioners can be expected.

[0117] In the communication adaptor 21B, although power is input to the insulating power supplier 210 from the external power supply 4, input and output are electrically insulated from each other by reinforced insulation. Further, the connection interface on the indoor unit 3B side of the low-voltage communicator 212A has reinforced insulation or double insulation to the external power supply 4. Similarly, in the communication adaptor 31B, although power is input to the insulating power supplier 310 from the external power supply 5, input and output are electrically insulated from each other by reinforced insulation. Further, the connection interface on the outdoor unit 2B side of the low-voltage communicator 312A has reinforced insulation or double insulation to the external power supply 5. As a result, expansion of sales channels into the above markets is further promoted.

[0118] In the communication adaptor 21B, the low-voltage communicator 212A communicates with another device by a full duplex communication, and between the high-voltage communicator 211 and the low-voltage communicator 212A, a transmission signal line and a reception signal line are cross-connected so as to be interchanged with each other. Thus, the communication adaptor 21B does not require the controller 213 in Embodiment 1, and can be thus smaller. Similarly, in the communication adaptor 31B, the low-voltage communicator 312A communicates with another device by a full duplex communication, and between the high-voltage communicator 311 and the low-voltage communicator 312A, a transmission signal line and a reception signal line are cross-connected so as to be interchanged with each other. Thus, the communication adaptor 31B does not require the controller 313 in Embodiment 1, and can be thus smaller,Embodiment 4

[0119] Next, Embodiment 4 of the present disclosure is described. In the following description, components that are in common with Embodiment 1 are assigned the same reference signs, and description of these components is omitted.

[0120] FIG. 7 illustrates an overall configuration of an air conditioning system 1C in Embodiment 4. The air conditioning system 1C is an example of the air conditioning system according to the present disclosure. The air-conditioning system 1C is a system that performs air conditioning of, for example, a building such as an office building or a shop, and includes the outdoor unit 2 and an indoor device 30B. The air conditioning system 1C may include a plurality of indoor devices 30B.

[0121] The indoor device 30B is an example of the indoor device according to the present disclosure. The indoor device 30B includes an insulating power supplier 303, a low-voltage communicator 304, the controller 302, and the non-illustrated indoor device main unit. The insulating power supplier 303 is a power supply circuit in which input and output are electrically insulated from each other by reinforced insulation, and outputs, to each of the low-voltage communicator 304, the controller 302, and the indoor device main unit, power required for operation thereof based on power input from the external power supply 5.

[0122] The low-voltage communicator 304 is a communication circuit for low-voltage communication with another device, and includes electronic components, such as a transistor and a photocoupler, and a communication driver IC. A communication protocol of the low-voltage communication is, for example, single-ended transmission such as RS232C, differential transmission such as RS-485 or a CAN, Ethernet (registered trademark), or the like. A connection interface on the outdoor unit 2 side of the low-voltage communicator 304 has reinforced insulation or double insulation to the external power supply 5.

[0123] As described above, the air conditioning system 1C in the present embodiment includes the communication adaptor 21 that performs high-voltage communication with the outdoor device 20 and low-voltage communication with a device different from the outdoor device 20, and the indoor device 30B configured to perform low-voltage communication with another device. Thus, by connecting the outdoor device 20 and the communication adaptor 21 to each other at shipping from a factory, high-voltage wiring work on site is unnecessary. As a result, expansion of sales channels into markets that require low-voltage wiring between air conditioners can be expected.

[0124] In the communication adaptor 21, although power is input to the insulating power supplier 210 from the external power supply 4, input and output are electrically insulated from each other by reinforced insulation. Further, the connection interface on an indoor device 30B side of the low-voltage communicator 212 has reinforced insulation or double insulation to the external power supply 4. In the indoor device 30B, although power is input to the insulating power supplier 303 from the external power supply 5, input and output are electrically insulated from each other by reinforced insulation. Further, the connection interface on the outdoor unit 2 side of the low-voltage communicator 304 has reinforced insulation or double insulation to the external power supply 5. As a result, expansion of sales channels into the above markets is further promoted.Embodiment 5

[0125] Next, Embodiment 5 of the present disclosure is described. In the following description, components that are in common with Embodiment 1 are assigned the same reference signs, and description of these components is omitted.

[0126] FIG. 8 illustrates an overall configuration of an air conditioning system 1D in Embodiment 5. The air conditioning system 1D is an example of the air conditioning system according to the present disclosure. The air-conditioning system 1D is a system that performs air conditioning of, for example, a building such as an office building or a shop, and includes an outdoor device 20B and the indoor unit 3. The air conditioning system 1D may include a plurality of indoor units 3.

[0127] The outdoor device 20B includes an insulating power supplier 203, a low-voltage communicator 204, the controller 202, and the non-illustrated outdoor device main unit. The insulating power supplier 203 is a power supply circuit in which input and output are electrically insulated from each other by reinforced insulation, and outputs, to each of the low-voltage communicator 204, the controller 202, and the outdoor device main unit, power required for operation thereof based on power input from the external power supply 4.

[0128] The low-voltage communicator 204 is a communication circuit for low-voltage communication with another device, and includes electronic components, such as a transistor and a photocoupler, and a communication driver IC. A communication protocol of the low-voltage communication is, for example, single-ended transmission such as RS232C, differential transmission such as RS-485 or a CAN, Ethemet (registered trademark), or the like. A connection interface on the indoor unit 3 side of the low-voltage communicator 204 has reinforced insulation or double insulation to the external power supply 4.

[0129] As described above, the air conditioning system 1D in the present embodiment includes the outdoor device 20B configured to perform low-voltage communication with another device, and the communication adaptor 31 that performs low-voltage communication with a device different from the indoor device 30. Thus, by connecting the indoor device 30 and the communication adaptor 31 to each other at shipping from a factory, high-voltage wiring work on site is unnecessary. As a result, expansion of sales channels into markets that require low-voltage wiring between air conditioners can be expected.

[0130] In the communication adaptor 31, although power is input to the insulating power supplier 310 from the external power supply 5, input and output are electrically insulated from each other by reinforced insulation. Further, the connection interface on the outdoor device 20B side of the low-voltage communicator 312 has reinforced insulation or double insulation to the external power supply 5. In the outdoor device 20B, although power is input to the insulating power supplier 203 from the external power supply 4, input and output are electrically insulated from each other by reinforced insulation. Further, the connection interface on the indoor unit 3 side of the low-voltage communicator 204 has reinforced insulation or double insulation to the extemal power supply 4. As a result, expansion of sales channels into the above markets is further promoted.

[0131] The present disclosure is not limited to the above embodiments, and various modifications are of course possible without departing from the gist of the present disclosure. For example, the technical ideas of the above embodiments may be combined as appropriate.

[0132] The foregoing describes some example embodiments for explanatory purposes. Although the foregoing discussion has presented specific embodiments, persons skilled in the art will recognize that changes may be made in form and detail without departing from the broader spirit and scope of the invention. Accordingly, the specification and drawings are to be regarded in an illustrative rather than a restrictive sense. This detailed description, therefore, is not to be taken in a limiting sense, and the scope of the invention is defined only by the included claims, along with the full range of equivalents to which such claims are entitled.INDUSTRIAL APPLICABILITY

[0133] The present disclosure can be suitably applied to a system for air conditioning of a building.REFERENCE SIGNS LIST1, 1A, 1B, IC, ID Air conditioning system

[0135] 2, 2A, 2B Outdoor unit

[0136] 3, 3A, 3B Indoor unit

[0137] 4, 5 External power supply

[0138] 6 Common line

[0139] 7 Power line

[0140] 8 Communication line

[0141] 20, A, 20B Outdoor device

[0142] 21, 21A, 21B, 31, 31A, 31B Communication adaptor

[0143] 30, 30A, 30B Indoor device

[0144] 200, 300 Power supplier

[0145] 201, 211, 301, 311 High-voltage communicator

[0146] 202, 213, 302, 313 Controller

[0147] 203, 210, 303, 310 Insulating power supplier

[0148] 204, 212, 212A, 304, 312, 312 Low-voltage communicator

[0149] 220 CPU

[0150] 221 ROM

[0151] 222 RAM

[0152] 223 I / O interface

[0153] 224 Auxiliary storage device

[0154] 400 DC power supply

[0155] 401, 423, 424, 425, 442, 443, 444, 502, 503, 504, 522, 523 Resistor

[0156] 402, 426, 470, 541 Diode

[0157] 403, 542 Constant-voltage diode

[0158] 404 Electrolytic capacitor

[0159] 420, 500 Transmission circuit

[0160] 421, 422, 501 PNP transistor

[0161] 427, 446, 447, 505, 525, 526 Ground terminal

[0162] 430, 450, 510, 530 Photocoupler

[0163] 431, 451, 511, 531 Light-emitting diode

[0164] 432, 452, 512, 532 Phototransistor

[0165] 440, 520 Reception circuit

[0166] 441, 521 NPN transistor

[0167] 445, 524 Power supply terminal

[0168] 460, 540 Communication driver IC

Claims

2. (canceled)3. (canceled)4. (canceled)5. An air conditioning system comprising:an outdoor device to perform communication based on a first voltage;an indoor device to perform communication based on the first voltage;an adaptor for the outdoor device; andan adaptor for the indoor device, wherein the adaptor for the outdoor device includesa first communicator to communicate with the outdoor device based on the first voltage, anda second communicator to communicate with the adaptor for the indoor device based on a second voltage lower than the first voltage,the second communicator transmits, to the adaptor for the indoor device, based on the second voltage, communication data received by the first communicator from the outdoor device,the first communicator transmits, to the outdoor device, based on the first voltage, communication data received by the second communicator from the adaptor for the indoor device,the outdoor device and the adaptor for the outdoor device are connected to each other with a first communication line and a first common line, the first communication line feeding, to the adaptor for the outdoor device, a current supplied from a direct-current power supply included in the outdoor device, the first common line feeding, from the adaptor for the outdoor device to the outdoor device, the current having flown through the first communication line.the first communicator includesa first transmission circuit including a first transmission photocoupler of which a conductive / non-conductive state is controlled in accordance with communication data to be transmitted to the outdoor device, the first transmission circuit being configured to control a conductive / non-conductive state of a first transmission path in accordance with the conductive / non-conductive state of the first transmission photocoupler, the first transmission path including the first communication line and the first common line, anda first reception circuit including a first reception photocoupler of which a conductive / non-conductive state is controlled in accordance with the conductive / non-conductive state of the first transmission path, the first reception circuit being configured to receive, by detecting the conductive / non-conductive state of the first reception photocoupler, communication data transmitted from the outdoor device,the adaptor for the indoor device includesa third communicator to communicate with the indoor device based on the first voltage, anda fourth communicator to communicate with the adaptor for the outdoor device based on the second voltage,the fourth communicator transmits, to the adaptor for the outdoor device, based on the second voltage, communication data received by the third communicator from the indoor device,the third communicator transmits, to the indoor device, based on the first voltage, communication data received by the fourth communicator from the adaptor for the outdoor device,the indoor device and the adaptor for the indoor device are connected to each other with a second communication line and a second common line, the second communication line feeding, to the indoor device, a current supplied from a direct-current power supply included in the adaptor for the indoor device, the second common line feeding, from the indoor device to the adaptor for the indoor device, the current having flown through the second communication line, andthe third communicator includesa second transmission circuit including a second transmission photocoupler of which a conductive / non-conductive state is controlled in accordance with communication data to be transmitted to the indoor device, the second transmission circuit being configured to control a conductive / non-conductive state of a second transmission path in accordance with the conductive / non-conductive state of the second transmission photocoupler, the second transmission path including the second communication line and the second common line, anda second reception circuit including a second reception photocoupler of which a conductive / non-conductive state is controlled in accordance with the conductive / non-conductive state of the second transmission path, the second reception circuit being configured to receive, by detecting the conductive / non-conductive state of the second reception photocoupler, communication data transmitted from the indoor device.

6. An air conditioning system comprising:an outdoor device to perform communication based on a first voltage;an indoor device to perform communication based on a second voltage lower than the first voltage; anda communication adaptor, whereinthe communication adaptor includesa first communicator to communicate with the outdoor device based on the first voltage, anda second communicator to communicate with the indoor device based on the second voltage,the second communicator transmits, to the indoor device, based on the second voltage, communication data received by the first communicator from the outdoor device, andthe first communicator transmits, to the outdoor device, based on the first voltage, communication data received by the second communicator from the indoor device,the outdoor device and the communication adaptor are connected to each other with a communication line and a common line, the communication line feeding, to the communication adaptor, a current supplied from a direct-current power supply included in the outdoor device, the common line feeding, from the communication adaptor to the outdoor device, the current having flown through the communication line, andthe first communicator includesa transmission circuit including a transmission photocoupler of which a conductive / non-conductive state is controlled in accordance with communication data to be transmitted to the outdoor device, the transmission circuit being configured to control a conductive / non-conductive state of a transmission path in accordance with the conductive / non-conductive state of the transmission photocoupler, the transmission path including the communication line and the common line, anda reception circuit including a reception photocoupler of which a conductive / non-conductive state is controlled in accordance with the conductive / non-conductive state of the transmission path, the reception circuit being configured to receive, by detecting the conductive / non-conductive state of the reception photocoupler, communication data transmitted from the outdoor device.

7. An air conditioning system comprising:an indoor device to perform communication based on a first voltage;an outdoor device to perform communication based on a second voltage lower than the first voltage; anda communication adaptor, whereinthe communication adaptor includesa first communicator to communicate with the indoor device based on the first voltage, anda second communicator to communicate with the outdoor device based on the second voltage,the second communicator transmits, to the outdoor device, based on the second voltage, communication data received by the first communicator from the indoor device,the first communicator transmits, to the indoor device, based on the first voltage, communication data received by the second communicator from the outdoor device,the indoor device and the communication adaptor are connected to each other with a communication line and a common line, the communication line feeding, to the indoor device, a current supplied from a direct-current power supply included in the communication adaptor, the common line feeding, from the indoor device to the communication adaptor, the current having flown through the communication line, andthe first communicator includesa transmission circuit including a transmission photocoupler of which a conductive / non-conductive state is controlled in accordance with communication data to be transmitted to the indoor device, the transmission circuit being configured to control a conductive / non-conductive state of a transmission path in accordance with the conductive / non-conductive state of the transmission photocoupler, the transmission path including the communication line and the common line, anda reception circuit including a reception photocoupler of which a conductive / non-conductive state is controlled in accordance with the conductive / non-conductive state of the transmission path, the reception circuit being configured to receive, by detecting the conductive / non-conductive state of the reception photocoupler, communication data transmitted from the indoor device.

8. The air conditioning system according to claim 5, whereinthe adaptor for the outdoor device further includes a first insulating power supplier in which input and output are electrically insulated from each other, the first insulating power supplier being configured to output power for driving the adaptor for the outdoor device based on power input from a first external power supply, andthe adaptor for the indoor device further includes a second insulating power supplier in which input and output are electrically insulated from each other, the second insulating power supplier being configured to output power for driving the adaptor for the indoor device based on power input from a second external power supply.

9. The air conditioning system according to claim 8, whereina connection interface with the adaptor for the indoor device in the second communicator has reinforced insulation or double insulation to the first external power supply, anda connection interface with the adaptor for the outdoor device in the fourth communicator has reinforced insulation or double insulation to the second external power supply.

10. The air conditioning system according to claim 5, whereinthe second communicator and the adaptor for the indoor device communicate with each other by a full duplex communication,between the first communicator and the second communicator, a transmission signal line and a reception signal line are connected to be interchanged with each other,the fourth communicator and the adaptor for the outdoor device communicate with each other by a full duplex communication, andbetween the third communicator and the fourth communicator, a transmission signal line and a reception signal line are connected to be interchanged with each other.

11. The air conditioning system according to claim 8, whereinthe second communicator and the adaptor for the indoor device communicate with each other by a full duplex communication,between the first communicator and the second communicator, a transmission signal line and a reception signal line are connected to be interchanged with each other,the fourth communicator and the adaptor for the outdoor device communicate with each other by a full duplex communication, andbetween the third communicator and the fourth communicator, a transmission signal line and a reception signal line are connected to be interchanged with each other.

12. The air conditioning system according to claim 9, whereinthe second communicator and the adaptor for the indoor device communicate with each other by a full duplex communication,between the first communicator and the second communicator, a transmission signal line and a reception signal line are connected to be interchanged with each other,the fourth communicator and the adaptor for the outdoor device communicate with each other by a full duplex communication, andbetween the third communicator and the fourth communicator, a transmission signal line and a reception signal line are connected to be interchanged with each other.

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