A multi-connected air conditioner communication system

Abstract

The utility model discloses a kind of multi-connected air conditioner communication systems, including the communication connection in Homebus bus on multiple indoor units and multiple outdoor units, any of outdoor unit and indoor unit is communication node, communication node includes: main control unit, it is used to control communication node;Communication chip, it is connected with main control unit, for receiving the communication signal from Homebus bus, and communication signal transmission sent by main control unit to Homebus bus;Anti-backflow circuit, it is connected between the signaling end of communication chip and Homebus bus, for when communication chip normal communication, the communication signal output by signaling end is transmitted to Homebus bus by anti-backflow circuit, and when communication chip power off, anti-backflow circuit disconnects the passage between Homebus bus and signaling end.The utility model can avoid the influence of power-off communication node to bus communication signal, ensure communication quality of communication system.

Description

Technical Field

[0001] This utility model relates to the field of air conditioning communication technology, and in particular to a multi-split air conditioning communication system. Background Technology

[0002] Multi-split air conditioning systems consist of an indoor unit system with multiple indoor units and an outdoor unit system with multiple outdoor units. Communication between the indoor and outdoor units typically uses the HomeBus (i.e., home bus system) communication protocol. Currently, most multi-split air conditioning systems use the Sanmei Electric MM1192 communication chip as the core, with various communication circuits, drive circuits, and protection circuits integrated in the periphery to form a HomeBus communication system.

[0003] Existing Homebus communication systems that rely on the MM1192 communication chip typically experience a situation where some communication nodes on the HomeBus are powered on while others are powered off. Since the powered-off communication nodes remain connected in parallel on the HomeBus, the powered-off communication nodes will pull down the bus communication signal during normal communication when the powered-on nodes are communicating. This results in a significant attenuation of the bus communication signal amplitude, severely affecting the communication quality and communication distance between normally powered-on communication nodes. Utility Model Content

[0004] In response to the problems mentioned in the background art, some embodiments of this application provide a multi-split air conditioning communication system. By setting an anti-backflow circuit between the communication chip transmitter end of the communication node and the HomeBus bus, the system prevents the bus communication signal from flowing back to the communication chip transmitter end, causing it to form a leakage circuit with the bus communication signal, thereby avoiding pulling down the bus communication signal and improving the communication quality of the entire communication system.

[0005] To achieve the above-mentioned objectives, the present invention employs the following technical solution: Some embodiments of this application relate to a multi-split air conditioning communication system, including multiple indoor units and multiple outdoor units communicatively connected to a Homebus bus, wherein any of the outdoor unit and indoor unit is a communication node, and the communication node includes: The master controller is used to control the communication nodes; A communication chip, which is communicatively connected to the main controller, is used to receive communication signals from the Homebus bus and transmit the communication signals sent by the main controller to the Homebus bus; An anti-backflow circuit is connected between the transmitting end of the communication chip and the Homebus bus. When the communication chip is communicating normally, the communication signal output by the transmitting end is transmitted to the Homebus bus through the anti-backflow circuit. When the communication chip is powered off, the anti-backflow circuit disconnects the path between the Homebus bus and the transmitting end.

[0006] The technical solutions involved in the above embodiments have the following advantages or beneficial effects: An anti-backflow circuit is installed between the transmitting end of the communication chip and the Homebus bus. The function of the anti-backflow circuit is to prevent the bus communication signal on the Homebus bus from flowing back to the transmitting end of the communication chip when the communication chip is powered off, so as not to affect the normal transmission of the transmitting end of the communication chip. Therefore, due to the existence of the anti-backflow circuit, when the communication chip is powered off, the bus communication signal cannot flow back to the transmitting end, so that the bus communication signal will not form a leakage current loop with the transmitting end, that is, the transmitting end will not pull down the bus communication signal level, ensuring that the communication performance of the entire communication system is not affected when some communication nodes on the Homebus are powered off.

[0007] In some embodiments of this application, the anti-backflow circuit is a switch control circuit, which is powered by the power supply of the communication chip; When the communication chip is powered off, the switch control circuit controls the disconnection of the connection between the transmitting end and the Homebus bus; When the communication chip is powered on, the switch control circuit controls the circuit connecting the transmitting end and the Homebus bus.

[0008] The technical solutions involved in the above embodiments have the following advantages or beneficial effects: The backflow prevention circuit uses a switch control circuit, which is powered by the communication chip's power supply. When the communication chip is powered off, its power supply does not output power, and the switch control circuit disconnects the loop between the transmitter and the Homebus bus. At this time, the bus communication signal will not flow back to the transmitter, and a leakage loop will not be formed between them, thus preventing the transmitter from pulling down the bus communication signal level and ensuring the quality of the bus communication signal.

[0009] In some embodiments of this application, the switch control circuit includes: The first relay has its coil powered by the power supply of the communication chip, and the normally open switch of the first relay is connected between the first differential bus of the Homebus bus and the second transmitting terminal of the communication chip. The second relay has its coil powered by the power supply of the communication chip, and the normally open switch of the second relay is connected between the second differential bus of the Homebus bus and the first transmitting terminal of the communication chip.

[0010] The technical solutions involved in the above embodiments have the following advantages or beneficial effects: The coils of the first relay and the second relay are both powered by the communication chip. When the communication chip is powered on normally, the coils of the first relay and the second relay are both powered on. The normally open switch of the first relay closes, connecting the path between the first differential bus and the second transmitting end. The normally open switch of the second relay closes, connecting the path between the second differential bus and the first transmitting end, thus realizing normal communication of the communication chip.

[0011] When the communication chip is powered off, the coils of both the first and second relays are de-energized. The normally open switch of the first relay opens, disconnecting the path between the first differential bus and the second transmitting end. The normally open switch of the second relay opens, disconnecting the path between the second differential bus and the first transmitting end. Therefore, the bus communication signal will not flow back to the transmitting end, and the transmitting end will not pull down the bus communication signal level, ensuring that the power-off communication node does not affect the communication of the remaining normal communication nodes on the Homebus bus.

[0012] In some embodiments of this application, the switch control circuit includes: The first optocoupler has its anode connected to the power supply of the communication chip, its cathode grounded, its collector connected to the second transmitting terminal of the communication chip, and its emitter connected to the first differential bus of the Homebus bus. The second optocoupler has its anode connected to the power supply of the communication chip, its cathode grounded, its collector connected to the first transmitting terminal of the communication chip, and its emitter connected to the second differential bus of the Homebus bus.

[0013] The technical solutions involved in the above embodiments have the following advantages or beneficial effects: Both the first and second optocouplers are powered by the communication chip's power supply. When the communication chip is powered on normally, both the first and second optocouplers are turned on. The first differential bus is connected to the second transmitting end through the first optocoupler, and the second differential bus is connected to the first transmitting end through the second optocoupler, thus realizing normal communication of the communication chip.

[0014] When the communication chip is powered off, both the first and second optocouplers are turned off. The path between the first differential bus and the second transmitter is disconnected due to the disconnection of the first optocoupler, and the path between the second differential bus and the first transmitter is disconnected due to the disconnection of the second optocoupler. Therefore, the bus communication signal will not flow back to the transmitter, and the transmitter will not pull down the bus communication signal level, ensuring that the power-off communication node does not affect the communication of the remaining normal communication nodes on the Homebus.

[0015] In some embodiments of this application, the backflow prevention circuit includes: The first diode has its anode connected to the second transmitting terminal of the communication chip and its cathode connected to the first differential bus of the Homebus bus. The second diode has its anode connected to the first transmitting terminal of the communication chip and its cathode connected to the second differential bus of the Homebus bus.

[0016] The technical solutions involved in the above embodiments have the following advantages or beneficial effects: Regardless of whether the communication chip is powered on or off, due to the single-phase conduction characteristic of the diode, the bus communication signal will not flow back to the transmitting end, and the transmitting end will not pull down the bus communication signal level, ensuring that the power-off communication node does not affect the communication of the remaining normal communication nodes on the Homebus bus.

[0017] In some embodiments of this application, the communication node further includes: The transmitting side AC coupling circuit is connected between the anti-backflow circuit and the Homebus bus, and is used to receive the communication signal output by the communication chip at the transmitting end and send it to the Homebus bus; The receiving-side AC coupling circuit is connected to the receiving end of the communication chip and is used to receive communication signals from the Homebus bus.

[0018] The technical solutions involved in the above embodiments have the following advantages or beneficial effects: To ensure reliable transmission and reception of the communication chip, an AC coupling circuit is set at the transmitting end of the communication chip and an AC coupling circuit is set at the receiving end.

[0019] In some embodiments of this application, the transmitting-side AC coupling circuit includes: A first capacitor is disposed between the backflow prevention circuit and the first differential bus of the Homebus bus; The second capacitor is disposed between the backflow prevention circuit and the first differential bus of the Homebus bus.

[0020] The technical solutions involved in the above embodiments have the following advantages or beneficial effects: Using a capacitor as the AC coupling circuit on the transmitting side can filter the communication signal output from the transmitting side, thereby improving the quality of the bus communication signal transmitted to the Homebus.

[0021] In some embodiments of this application, the receiving-side AC coupling circuit includes: The first RC circuit has one end connected to the first differential bus of the Homebus bus and the other end connected to the first transceiver terminal of the communication chip. The second RC circuit has one end connected to the second differential bus of the Homebus bus and the other end connected to the second transceiver terminal of the communication chip.

[0022] The technical solutions involved in the above embodiments have the following advantages or beneficial effects: Using an RC circuit as the AC coupling circuit on the receiving side can process the signals sent from the Homebus bus to the receiving end of the communication chip, thereby improving the quality of the communication signals transmitted to the communication chip.

[0023] In some embodiments of this application, the communication node further includes: A bus drive circuit is disposed between the transmitting end of the communication chip and the anti-backflow circuit.

[0024] The technical solutions involved in the above embodiments have the following advantages or beneficial effects: A bus drive circuit is used to drive the signal output by the amplification communication chip at the transmitting end. Attached Figure Description

[0025] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0026] Figure 1 A block diagram illustrating the principle of communication between multiple communication nodes in an existing multi-split air conditioning system; Figure 2 A block diagram illustrating the principle of communication between multiple communication nodes in the multi-split air conditioning communication system proposed in this application; Figure 3 A schematic diagram illustrating the communication principle between the indoor and outdoor units in the multi-split air conditioning communication system proposed in this application; Figure 4 This is a schematic diagram of the communication principle between a communication node of the multi-split air conditioning communication system proposed in this application and the Homebus bus. Figure 1; Figure 5 This is a schematic diagram of the communication principle between a communication node of the multi-split air conditioning communication system proposed in this application and the Homebus bus. Figure 2 ; Figure 6 This is a schematic diagram of the communication principle between a communication node of the multi-split air conditioning communication system proposed in this application and the Homebus bus. Figure 3 ; Figure 7 This is a circuit diagram showing the communication between a communication node of the multi-split air conditioning communication system proposed in this application and the Homebus bus. Figure 8 This is a schematic diagram of an embodiment of the anti-backflow circuit in the multi-split air conditioning communication system proposed in this application; Figure 9 This is a schematic diagram of another embodiment of the anti-backflow circuit in the multi-split air conditioning communication system proposed in this application; Figure 10 This is a schematic diagram of another embodiment of the anti-backflow circuit in the multi-split air conditioning communication system proposed in this application; Figure label: 100. Communication node; 110. Communication chip; 120. Anti-backflow circuit; 130. Receiver-side AC coupling circuit; 140. Transmitter-side AC coupling circuit; 150. Bus drive loop; 200 Indoor unit; 210 Indoor main controller; 220 Indoor communication chip; 230 Indoor backflow prevention circuit; 300 Outdoor unit; 310 Outdoor main controller; 320 Outdoor communication chip; 330 Outdoor backflow prevention circuit. Detailed Implementation

[0027] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0028] In the description of this application, it should be understood that the terms "center", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application.

[0029] The terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this application, unless otherwise stated, "a plurality of" means two or more.

[0030] In the description of this application, it should be noted that, unless otherwise expressly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection between two components. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.

[0031] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0032] The following disclosure provides many different embodiments or examples for implementing various structures of this invention. To simplify the disclosure, specific examples of components and arrangements are described below. These are merely examples and are not intended to limit the scope of the invention. Furthermore, reference numerals and / or letters may be repeated in different examples; such repetition is for simplification and clarity and does not in itself indicate a relationship between the various embodiments and / or arrangements discussed. In addition, examples of various specific processes and materials are provided in this invention, but those skilled in the art will recognize the application of other processes and / or the use of other materials.

[0033] Basic working principle of air conditioners Air conditioners execute a refrigeration cycle using a compressor, condenser, expansion valve, and evaporator. The refrigeration cycle involves a series of processes, including compression, condensation, expansion, and evaporation, to cool or heat an indoor space.

[0034] Low-temperature, low-pressure refrigerant enters the compressor, which compresses it into a high-temperature, high-pressure refrigerant gas and discharges the compressed refrigerant gas. The discharged refrigerant gas flows into the condenser. The condenser condenses the compressed refrigerant into a liquid phase, and the heat is released to the surrounding environment through the condensation process.

[0035] The expansion valve expands the high-temperature, high-pressure liquid refrigerant that condenses in the condenser into a low-pressure liquid refrigerant. The evaporator evaporates the expanded refrigerant in the expansion valve and returns the low-temperature, low-pressure refrigerant gas to the compressor. The evaporator achieves its cooling effect by utilizing the latent heat of refrigerant evaporation to exchange heat with the material being cooled. Throughout the cycle, the air conditioner regulates the temperature of the indoor space.

[0036] The outdoor unit of an air conditioner refers to the part of the refrigeration cycle that includes the compressor and the outdoor heat exchanger. The indoor unit of an air conditioner includes the indoor heat exchanger, and an expansion valve can be provided in either the indoor or outdoor unit.

[0037] The indoor and outdoor heat exchangers function as either condensers or evaporators. When the indoor heat exchanger is used as a condenser, the air conditioner functions as a heater in heating mode; when the indoor heat exchanger is used as an evaporator, the air conditioner functions as a cooler in cooling mode.

[0038] This application relates to a communication system for multi-split air conditioning systems. The basic working principle of a multi-split air conditioning system is described above in the section on the basic working principle of an air conditioner.

[0039] In some embodiments of this application, the multi-split air conditioning system includes multiple indoor units and multiple outdoor units that are sequentially connected to a Homebus communication bus. The indoor units and outdoor units communicate using differential signals on the Homebus bus.

[0040] Each of the indoor and outdoor units is a communication node, used to send and receive bus communication signals transmitted via the Homebus bus.

[0041] Both indoor and outdoor units can serve as transmitting communication nodes, and both can serve as receiving communication nodes that communicate with transmitting communication nodes. The terms "transmitting" and "receiving" are relative.

[0042] See Figure 1 It shows multiple communication chips connected to the Homebus bus. Each communication chip belongs to a communication node, which can be either an indoor unit or an outdoor unit.

[0043] The communication chip receives signals that have undergone Alternate Mark Inversion (AMI) (or simply AMI signals).

[0044] All communication chips have a Homebus interface for connecting to the Homebus bus.

[0045] The Homebus includes a first differential bus (BUS-A) and a second differential bus (BUS-B), on which the bus AMI signal is transmitted.

[0046] For ease of description, any communication node (an indoor unit or an outdoor unit) is denoted as communication node 100.

[0047] In some embodiments of this application, the communication chip 110 in the communication node 100 often uses the MM1192 chip (see...). Figure 7 The transmitting end (including the first transmitting end OUT(A) and the second transmitting end OUT(B)) is equipped with a Pbase resistor, and a parasitic PNP transistor is formed between the Pbase resistor and the Vcc of the communication chip 110.

[0048] When the communication chip 110 is powered normally, the base voltage of the parasitic PNP transistor is higher than that of the other two terminals, and there is no leakage circuit.

[0049] When the communication chip 110 is not powered (i.e., the voltage drops to 0), the base voltage of the parasitic PNP transistor is pulled low. At the same time, the transmitting end will also receive the bus communication signal on the Homebus. That is, a high level will be applied to the Pbase resistor, and the parasitic PNP transistor will conduct, forming a leakage circuit. This manifests as a lower impedance of the communication circuit. The leakage circuit will form a large voltage drop, causing the amplitude of the bus communication signal level to be pulled low, resulting in communication abnormalities.

[0050] Therefore, in some embodiments of this application, see Figure 2 An anti-backflow circuit is set at the transmitting end of the communication chip to prevent the bus communication signal from flowing back to the transmitting end of the communication chip when the communication chip is powered off. This avoids the formation of a leakage current loop with the transmitting end, which would lower the amplitude of the bus communication signal level. As a result, the communication quality of multiple normally operating communication nodes on the Homebus is not affected by the power outage of the communication nodes.

[0051] See Figure 2 Each communication chip has an anti-backflow circuit on its transmitting side to prevent a power outage of one communication chip from affecting the communication of other normally functioning communication nodes.

[0052] See Figure 3 The following explanation will be based on the example of indoor unit 200 as one communication node and outdoor unit 300 as another communication node 100.

[0053] In some embodiments of this application, in order to enable communication between communication nodes, the indoor unit 200 includes an indoor main controller 210, an indoor communication chip 220, and an indoor anti-backflow circuit 230; the outdoor unit 300 includes an outdoor main controller 310, an outdoor communication chip 320, and an outdoor anti-backflow circuit 330.

[0054] The indoor communication chip 220 and the outdoor communication chip 320 have the same structure, and the indoor anti-backflow circuit 230 and the outdoor anti-backflow circuit 330 are also the same.

[0055] When the indoor unit 200 is powered off while the outdoor unit 300 is operating normally, the bus communication signal on the Homebus will not flow back to the transmitting end of the indoor communication chip 220 due to the indoor-side anti-backflow circuit 230, thus preventing the bus communication signal from being pulled down and affecting the quality of the bus communication signal.

[0056] When the indoor unit 200 is working normally while the outdoor unit 300 is powered off, the bus communication signal on the Homebus will not flow back to the transmitting end of the outdoor communication chip 320 due to the outdoor side anti-backflow circuit 330, thus preventing the bus communication signal from being pulled down and affecting the quality of the bus communication signal.

[0057] See Figure 4 Let's take a communication node 100 as an example for explanation.

[0058] The communication node 100 includes a communication chip 110 and an anti-backflow circuit 120, which is disposed between the transmitting end of the communication chip 110 and the Homebus bus.

[0059] The backflow prevention circuit 120 here is the same as the indoor backflow prevention circuit 230 and the outdoor backflow prevention circuit 330 mentioned above. The difference in name and designation is only for ease of description.

[0060] In some embodiments of this application, in order to achieve normal communication between communication nodes 100, it is also necessary to set peripheral circuits for communication chip 110.

[0061] The peripheral circuit described above includes: a demodulation circuit (not shown), a modulation circuit (not shown), a signal coupling circuit, and a bus drive circuit 150.

[0062] In some embodiments of this application, the modulation circuit and demodulation circuit are the communication circuits between the main control chip (not shown) and the communication chip 110 in the communication node 100.

[0063] When receiving signals, the AMI signal from the Homebus is received by the communication chip 110. The signal output from its DataOut terminal is converted by the demodulation circuit and then received by the signal receiving terminal RXD of the main control chip.

[0064] During transmission, after processing by the main control chip, the signal output at the main control chip's signal transmission terminal TXD is sent to the modulation circuit. After being converted by the modulation circuit, the output signal is then input to the DataIn terminal of the communication chip 110.

[0065] In some embodiments of this application, the signal coupling circuit is used to send and receive communication commands for the communication chip 110.

[0066] See Figure 5 and Figure 6 The signal coupling circuit includes a receiving-side AC coupling circuit 130 and a transmitting-side AC coupling circuit 140.

[0067] The receiving-side AC coupling circuit 130 is used to receive communication signals sent from the transmitting end of the transmitting communication node 100 on the Homebus bus, and send them to the receiving end of the communication chip 110 of the receiving communication node 100.

[0068] The AC coupling circuit 130 on the receiving side is implemented by selecting appropriate resistors and capacitors to ensure that the signal received from the Homebus bus is filtered out from noise such as DC signals.

[0069] See Figure 7 The AC coupling circuit 130 on the receiving side of the communication node 100 is shown to use a resistor and a capacitor in series, or a resistor and a capacitor in parallel, etc.

[0070] A first resistor R10 and a first capacitor C9 are connected in series between the second receiving terminal IN (1) of the receiving terminal of the communication chip 110 in the first differential bus BUS-A and the communication node 100.

[0071] The AC coupling circuit 140 on the transmitting side is used to receive the communication signal output by the communication chip 110 of the transmitting communication node 100 at the transmitting end and send it to the Homebus bus.

[0072] The AC coupling circuit 140 on the transmitting side is implemented by selecting appropriate resistors and capacitors to ensure that the signal sent to the Homebus bus is filtered out of noise such as DC signals.

[0073] exist Figure 7 The diagram shows that the AC coupling circuit 140 on the transmitting side of the communication node 100 is implemented using capacitors connected in series (e.g., capacitors C6 and C7).

[0074] Due to the technical requirements of the MM1192 communication chip, see [link / reference]. Figures 5 to 7 A bus drive circuit 150 is also connected between BUS-A and BUS-B of the Homebus bus to drive the signal output by the amplification communication chip 110 at the transmitting end.

[0075] See Figure 7 The bus drive circuit 150 includes an NPN transistor Q6 connected to the output pins OUT(a) and OUT(A) of the MM1192 communication chip 110 and an NPN transistor Q7 connected to the output pins OUT(b) and OUT(B) of the MM1192 communication chip 110, which are used to drive the amplified output signal.

[0076] See Figures 5 to 7 The backflow prevention circuit 120 can be set at the front end of the bus drive circuit 150.

[0077] In some embodiments of this application, to achieve the purpose of preventing backflow of bus communication signals, see [link to relevant documentation]. Figures 8 to 10 Different implementations of the backflow prevention circuit 120 are given.

[0078] In some embodiments of this application, the backflow prevention circuit 120 can be a switch control circuit, which is connected between the transmitting end of the communication chip 110 and the Homebus bus, and is controlled by the power supply Vcc of the communication chip 110.

[0079] In some embodiments of this application, see Figure 8 The switch control circuit includes a first relay RY1 and a second relay RY2.

[0080] The coils of the first relay RY1 and the second relay RY2 are both powered by the power supply Vcc of the communication chip 110.

[0081] The normally open switch of the first relay RY1 is connected between the first differential bus BUS-A and the second transmitting terminal OUT(B) of the communication chip 110; the normally open switch of the first relay RY2 is connected between the second differential bus BUS-B and the first transmitting terminal OUT(A) of the communication chip 110.

[0082] See Figure 8 The normally open switch of the first relay RY1 is connected between the second transmitting terminal OUT(B) of the communication chip 110 and the end of the capacitor C6 that is not connected to the first differential bus BUS-A; the normally open switch of the second relay RY2 is connected between the first transmitting terminal OUT(A) of the communication chip 110 and the end of the capacitor C7 that is not connected to the second differential bus BUS-B.

[0083] When the communication chip 110 is working normally, Vcc is energized, and the coils of the first relay RY1 and the second relay RY2 are both energized. At this time, the normally open switches of the first relay RY1 and the second relay RY2 are both closed.

[0084] The normally open switch of the first relay RY1 connects the second transmitting terminal OUT(B) of the communication chip 110 and the first differential bus BUS-A. The normally open switch of the second relay RY2 connects the first transmitting terminal OUT(A) of the communication chip 110 and the second differential bus BUS-B. The communication chip 110 transmits normally.

[0085] When the communication chip 110 is de-energized, Vcc is de-energized, and the coils of the first relay RY1 and the second relay RY2 are both de-energized. At this time, the normally open switches of the first relay RY1 and the second relay RY2 are both open.

[0086] The normally open switch of the first relay RY1 and the normally open switch of the second relay RY2 disconnect the circuit between the transmitting end of the communication chip 110 and the Homebus bus. The bus communication signal on the Homebus bus cannot flow back to the transmitting end of the communication chip 110, and the transmitting end of the communication chip 110 cannot lower the amplitude of the bus communication signal. Thus, the quality of the bus communication signal is not affected. That is, the power failure of the communication node 100 does not affect the bus communication between other normal communication nodes 100.

[0087] In some embodiments of this application, see Figure 9 The switch control circuit includes a first optocoupler PC1 and a second optocoupler PC2.

[0088] Both the first optocoupler PC1 and the second optocoupler PC2 are powered by the power supply Vcc of the communication chip 110.

[0089] The anode of the first optocoupler PC1 is connected to the power supply Vcc, the cathode is grounded, the emitter is connected to the first differential bus BUS-A, and the collector is connected to the second transmitting terminal OUT(B); the anode of the second optocoupler PC2 is connected to the power supply Vcc, the cathode is grounded, the emitter is connected to the second differential bus BUS-B, and the collector is connected to the first transmitting terminal OUT(A).

[0090] See Figure 9 The emitter connection capacitor C6 of the first optocoupler PC1 is not connected to one end of the first differential bus BUS-A, and the emitter connection capacitor C7 of the second optocoupler PC2 is not connected to one end of the second differential bus BUS-B.

[0091] When the communication chip 110 is working normally, Vcc is powered, and both the first optocoupler PC1 and the second optocoupler PC2 are turned on. The first optocoupler PC1 connects the second transmitting terminal OUT(B) of the communication chip 110 and the first differential bus BUS-A, and the second optocoupler PC2 connects the first transmitting terminal OUT(A) of the communication chip 110 and the second differential bus BUS-B. The communication chip 110 transmits normally.

[0092] When the communication chip 110 is powered off, Vcc is de-energized, and both the first optocoupler PC1 and the second optocoupler PC2 are disconnected, thus breaking the loop between the transmitting end of the communication chip 110 and the Homebus bus. The bus communication signal on the Homebus bus cannot flow back to the transmitting end of the communication chip 110, and the transmitting end of the communication chip 110 cannot lower the amplitude of the bus communication signal. Thus, the quality of the bus communication signal is not affected. That is, the power outage of the communication node 100 does not affect the bus communication between other normal communication nodes 100.

[0093] In some embodiments of this application, see Figure 10 The anti-backflow circuit 120 also includes a first diode D1 and a second diode D2, which utilize the unidirectional conduction characteristic of diodes to prevent backflow of bus communication signals.

[0094] See Figure 10 The anode of the first diode D1 is connected to the second transmitting terminal OUT(B) of the communication chip 110 and the cathode is connected to the first differential bus BUS-A. The anode of the second diode D2 is connected to the first transmitting terminal OUT(A) of the communication chip 110 and the cathode is connected to the second differential bus BUS-B.

[0095] Due to the unidirectional conductivity of diodes, in this embodiment, regardless of whether the communication chip 110 is powered on or off, the bus communication signal on the Homebus cannot be backflowed to the transmitting end of the communication chip 110, thus achieving the purpose of not lowering the amplitude of the bus communication signal level when the power is off.

[0096] The multi-split air conditioning communication system involved in this application connects multiple communication nodes 100 on the Homebus bus. By setting an anti-backflow circuit 120 at the transmitting end of the communication chip 110 in each communication node 100, the backflow of the bus communication signal to the transmitting end of the communication chip 110 of the power-off communication node 100 is prevented, which would cause the amplitude of the bus communication signal to be pulled down. This ensures that the remaining normally operating communication nodes 100 on the Homebus bus are not affected by the power-off communication nodes 100, thus ensuring the normal communication of the normally operating communication nodes 100.

[0097] In the description of the above embodiments, specific features, structures, materials, or characteristics may be combined in any suitable manner in one or more embodiments or examples.

[0098] The above are merely specific embodiments of this utility model, but the protection scope of this utility model is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in this utility model should be included within the protection scope of this utility model. Therefore, the protection scope of this utility model should be determined by the scope of the claims.

Claims

1. A multi-split air conditioning communication system, characterized in that, This includes multiple indoor units and multiple outdoor units connected to the Homebus bus, where each outdoor unit and indoor unit is a communication node. The communication node includes: The master controller is used to control the communication nodes; A communication chip, which is communicatively connected to the main controller, is used to receive communication signals from the Homebus bus and transmit the communication signals sent by the main controller to the Homebus bus; An anti-backflow circuit is connected between the transmitting end of the communication chip and the Homebus bus. When the communication chip is communicating normally, the communication signal output by the transmitting end is transmitted to the Homebus bus through the anti-backflow circuit. When the communication chip is powered off, the anti-backflow circuit disconnects the path between the Homebus bus and the transmitting end.

2. The multi-split air conditioning communication system according to claim 1, characterized in that, The backflow prevention circuit is a switch control circuit, which is powered by the power supply of the communication chip. When the communication chip is powered off, the switch control circuit controls the disconnection of the path between the transmitting end and the Homebus bus; When the communication chip is powered on, the switch control circuit controls the connection between the transmitting end and the Homebus bus.

3. The multi-split air conditioning communication system according to claim 2, characterized in that, The switch control circuit includes: The first relay has its coil powered by the power supply of the communication chip, and the normally open switch of the first relay is connected between the first differential bus of the Homebus bus and the second transmitting terminal of the communication chip. The second relay has its coil powered by the power supply of the communication chip, and the normally open switch of the second relay is connected between the second differential bus of the Homebus bus and the first transmitting terminal of the communication chip.

4. The multi-split air conditioning communication system according to claim 2, characterized in that, The switch control circuit includes: The first optocoupler has its anode connected to the power supply of the communication chip, its cathode grounded, its collector connected to the second transmitting terminal of the communication chip, and its emitter connected to the first differential bus of the Homebus bus. The second optocoupler has its anode connected to the power supply of the communication chip, its cathode grounded, its collector connected to the first transmitting terminal of the communication chip, and its emitter connected to the second differential bus of the Homebus bus.

5. The multi-split air conditioning communication system according to claim 1, characterized in that, The backflow prevention circuit includes: The first diode has its anode connected to the second transmitting terminal of the communication chip and its cathode connected to the first differential bus of the Homebus bus. The second diode has its anode connected to the first transmitting terminal of the communication chip and its cathode connected to the second differential bus of the Homebus bus.

6. The multi-split air conditioning communication system according to claim 1, characterized in that, The communication node also includes: The transmitting side AC coupling circuit is connected between the anti-backflow circuit and the Homebus bus, and is used to receive the communication signal output by the communication chip at the transmitting end and send it to the Homebus bus; The receiving-side AC coupling circuit is connected to the receiving end of the communication chip and is used to receive communication signals from the Homebus bus.

7. The multi-split air conditioning communication system according to claim 6, characterized in that, The AC coupling circuit on the transmitting side includes: A first capacitor is disposed between the backflow prevention circuit and the first differential bus of the Homebus bus; The second capacitor is disposed between the backflow prevention circuit and the first differential bus of the Homebus bus.

8. The multi-split air conditioning communication system according to claim 6, characterized in that, The receiving-side AC coupling circuit includes: The first RC circuit has one end connected to the first differential bus of the Homebus bus and the other end connected to the first transceiver terminal of the communication chip. The second RC circuit has one end connected to the second differential bus of the Homebus bus and the other end connected to the second transceiver terminal of the communication chip.

9. The multi-split air conditioning communication system according to claim 1, characterized in that, The communication node also includes: A bus drive circuit is disposed between the transmitting end of the communication chip and the anti-backflow circuit.

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