CN107241252B - CAN communication polarity control circuit and system and multi-connected air conditioning system - Google Patents

CAN communication polarity control circuit and system and multi-connected air conditioning system Download PDF

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Publication number
CN107241252B
CN107241252B CN201710526063.4A CN201710526063A CN107241252B CN 107241252 B CN107241252 B CN 107241252B CN 201710526063 A CN201710526063 A CN 201710526063A CN 107241252 B CN107241252 B CN 107241252B
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Prior art keywords
transceiver
communication
level
polarity
signal
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CN107241252A (en
Inventor
苏玉海
李翠娟
刘志辉
玉维友
唐杰
刘桂鹏
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Gree Electric Appliances Inc of Zhuhai
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Gree Electric Appliances Inc of Zhuhai
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    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L12/00—Data switching networks
    • H04L12/28—Data switching networks characterised by path configuration, e.g. LAN [Local Area Networks] or WAN [Wide Area Networks]
    • H04L12/40—Bus networks
    • H04L12/40006—Architecture of a communication node
    • H04L12/40013—Details regarding a bus controller
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L12/00—Data switching networks
    • H04L12/28—Data switching networks characterised by path configuration, e.g. LAN [Local Area Networks] or WAN [Wide Area Networks]
    • H04L12/40—Bus networks
    • H04L12/40006—Architecture of a communication node
    • H04L12/40019—Details regarding a bus master
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L12/00—Data switching networks
    • H04L12/28—Data switching networks characterised by path configuration, e.g. LAN [Local Area Networks] or WAN [Wide Area Networks]
    • H04L12/40—Bus networks
    • H04L2012/40208—Bus networks characterized by the use of a particular bus standard
    • H04L2012/40215—Controller Area Network CAN
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L12/00—Data switching networks
    • H04L12/28—Data switching networks characterised by path configuration, e.g. LAN [Local Area Networks] or WAN [Wide Area Networks]
    • H04L12/40—Bus networks
    • H04L2012/4026—Bus for use in automation systems
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
    • Y02P90/00—Enabling technologies with a potential contribution to greenhouse gas [GHG] emissions mitigation
    • Y02P90/02—Total factory control, e.g. smart factories, flexible manufacturing systems [FMS] or integrated manufacturing systems [IMS]

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  • Engineering & Computer Science (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Signal Processing (AREA)
  • Selective Calling Equipment (AREA)

Abstract

The invention discloses a CAN communication polarity control circuit and system and a multi-connected air conditioning system. Wherein, this CAN communication polarity control circuit and system and ally oneself with air conditioning system includes: a chip selection signal receiving end for receiving a chip selection signal; the switch control tube is connected with the chip selection signal receiving end; and the CAN transceiver is connected with the switch control tube, connected with the CAN communication bus and used for matching with the polarity of the CAN communication bus according to the attribute of the chip selection signal. The invention solves the technical problem that the CAN communication system in the related technology is easy to have abnormal communication in order to realize consistent signal direction.

Description

CAN communication polarity control circuit and system and multi-connected air conditioning system
Technical Field
The invention relates to the field of circuits, in particular to a CAN communication polarity control circuit, a CAN communication polarity control system and a multi-connected air conditioning system.
Background
In a Controller Area Network (CAN) communication system, different components perform data interaction in a CAN communication manner, for example, a multi-connected air conditioning system, in the multi-connected air conditioning system, a multi-connected internal and external unit performs data interaction in the CAN communication manner, a physical layer signal of a communication mechanism is a differential signal, and a communication direction exists in two directions of CAN _ H, CAN _ L (hereinafter, the two directions are defined as the polarities of a CAN communication bus). In the whole communication network, the CAN communication of the multi-connected internal and external units CAN realize normal communication only by ensuring that the CAN _ H and CAN _ L signal directions are consistent. Can come the CAN _ H and the CAN _ L signal direction unanimity of controlling the multi-gang indoor unit through the mode of standard wiring in the factory, but CAN increase the unit cost like this, also CAN appear the problem that the wiring CAN not satisfy the actual length demand of engineering installation simultaneously, further lead to the engineering installation to refute at will and connect the communication line, the unusual problem of communication appears.
In order to solve the problem that communication abnormity is easy to occur in a CAN communication system in the related art in order to achieve consistency of signal directions, an effective solution is not provided at present.
Disclosure of Invention
The embodiment of the invention provides a CAN communication polarity control circuit, a system and a multi-connected air conditioning system, which at least solve the problem that in order to realize consistent signal direction, a CAN communication system in the related technology is easy to have abnormal communication.
According to an aspect of an embodiment of the present invention, there is provided a CAN communication polarity control circuit, including: a chip selection signal receiving end for receiving a chip selection signal; the switch control tube is connected with the chip selection signal receiving end; and the CAN transceiver is connected with the switch control tube, connected with the CAN communication bus and used for matching with the polarity of the CAN communication bus according to the attribute of the chip selection signal.
Further, the CAN transceiver is used for matching the polarity of the CAN communication bus according to the level of the chip selection signal.
Further, the switching control tube includes: a first switching control tube Q1; the second switch controls a tube Q2. The CAN transceiver includes: the first CAN transceiver U1 is connected with the first switch control tube Q1; and the second CAN transceiver U2 is connected with the second switch control tube Q2.
Further, the CAN communication polarity control circuit further includes: and the level inverter U4 is arranged between the first switch control tube Q1 and the second switch control tube Q2.
Further, the control terminal of the first switch control tube Q1 is connected to the chip select signal receiving terminal, and the first switch control tube Q1 is also connected to the power port of the first CAN transceiver U1. The control end of the second switch control tube Q2 is connected to the chip select signal receiving end, and the second switch control tube Q2 is further connected to the power port of the second CAN transceiver U2.
Further, the CAN communication bus comprises a first CAN signal line and a second CAN signal line. The first CAN signal interface CAN _ H of the first CAN transceiver U1 and the second CAN signal interface CAN _ L of the second CAN transceiver U2 are connected to the first CAN signal line. The second CAN signal interface CAN _ L of the first CAN transceiver U1 and the first CAN signal interface CAN _ H of the second CAN transceiver U2 are connected to the second CAN signal line.
Further, the level of the chip select signal is a first level or a second level, wherein when the level of the chip select signal is the first level, the first switch control tube Q1 is in a conducting state, the first CAN transceiver U1 is in a power-up state, and when the level of the chip select signal is the second level, the second switch control tube Q2 is in a conducting state, and the second CAN transceiver U2 is in a power-up state.
According to another aspect of the embodiments of the present invention, there is also provided a CAN communication system, including: a CAN communication bus; CAN communication polarity control circuit, wherein, CAN communication polarity control circuit includes: the chip selection signal receiving end is used for receiving a chip selection signal, wherein the level of the chip selection signal is a first level or a second level; the switch control tube is connected with the chip selection signal receiving end; and the CAN transceiver is connected with the switch control tube, connected with the CAN communication bus and used for matching the polarity of the CAN communication bus according to the level of the chip selection signal.
Further, the CAN communication bus includes: a first CAN signal line; a second CAN signal line. The switch control tube includes: a first switching control tube Q1; the second switch controls a tube Q2. The CAN transceiver includes: the first CAN transceiver U1 is connected with the first switch control tube Q1; and the second CAN transceiver U2 is connected with the second switch control tube Q2. The first CAN signal interface CAN _ H of the first CAN transceiver U1 and the second CAN signal interface CAN _ L of the second CAN transceiver U2 are connected to the first CAN signal line, and the second CAN signal interface CAN _ L of the first CAN transceiver U1 and the first CAN signal interface CAN _ H of the second CAN transceiver U2 are connected to the second CAN signal line.
Further, the CAN communication system further includes: and the microprocessor is connected with the CAN transceiver and used for outputting the chip selection signal to a chip selection signal receiving end.
According to another aspect of the embodiment of the invention, a multi-connected air conditioning system is further provided, and the multi-connected air conditioning system comprises any one of the CAN communication polarity control circuits provided by the invention.
In the embodiment of the invention, the CAN communication polarity control circuit and system and the multi-connected air-conditioning system which comprise the following structures are adopted: a chip selection signal receiving end for receiving a chip selection signal; the switch control tube is connected with the chip selection signal receiving end; and the CAN transceiver is connected with the switch control tube, is connected with the CAN communication bus and is used for matching the polarity of the CAN communication bus according to the attribute of the chip selection signal, so that the technical effect of automatic switching of the CAN communication polarity is realized, and the problem that the CAN communication system in the related technology is easy to have communication abnormity in order to realize consistent signal direction is solved.
Drawings
The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this application, illustrate embodiment(s) of the invention and together with the description serve to explain the invention and do not constitute a limitation of the invention. In the drawings:
fig. 1 is a flowchart of a CAN communication polarity control method according to a first embodiment of the present invention;
fig. 2 is a flowchart of a CAN communication polarity control method according to a second embodiment of the present invention;
fig. 3 is a flowchart of a CAN communication polarity control method according to a third embodiment of the present invention;
fig. 4 is a schematic view of a multi-connected air conditioning unit according to an embodiment of the present invention;
FIG. 5 is a schematic diagram of a CAN communication polarity control circuit according to an embodiment of the present invention;
fig. 6 is a schematic diagram of a CAN communication polarity control apparatus according to a first embodiment of the present invention;
fig. 7 is a schematic diagram of a CAN communication polarity control apparatus according to a second embodiment of the present invention; and
fig. 8 is a schematic diagram of a CAN communication polarity control apparatus according to a third embodiment of the present invention.
Detailed Description
In order to make those skilled in the art better understand the technical solutions of the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
It should be noted that the terms "first," "second," and the like in the description and claims of the present invention and in the drawings described above are used for distinguishing between similar elements and not necessarily for describing a particular sequential or chronological order. It is to be understood that the data so used is interchangeable under appropriate circumstances such that the embodiments of the invention described herein are capable of operation in sequences other than those illustrated or described herein. Furthermore, the terms "comprises," "comprising," and "having," and any variations thereof, are intended to cover a non-exclusive inclusion, such that a process, method, system, article, or apparatus that comprises a list of steps or elements is not necessarily limited to those steps or elements expressly listed, but may include other steps or elements not expressly listed or inherent to such process, method, article, or apparatus.
It should be noted that the steps shown in the flowchart of the figure may be executed in a computer system such as a set of computer executable instructions, and that while a logical order is shown in the flowchart, in some cases, the steps shown or described may be executed in an order different from that shown or described herein.
Fig. 1 is a flowchart of a CAN communication polarity control method according to a first embodiment of the present invention.
In this embodiment, the CAN communication polarity control method includes:
step S102, receiving a chip selection signal.
The chip select signal is a signal provided to the switch control transistor, so that the switch control transistor can perform corresponding switch control according to the signal, the chip select signal has different attributes, and the different attributes may carry different identification information, for example, when the chip select signal carries first information, the attribute of the chip select signal is a first attribute, and when the chip select signal carries second information, the attribute of the chip select signal is a second attribute. Alternatively, the chip select signal may be a signal having different levels, for example, the chip select signal may be high level or low level.
Step S104, acquiring the attribute of the chip selection signal.
The attribute of the chip select signal may be a first attribute or a second attribute, and the first attribute and the second attribute may be an attribute carrying a first identifier and an attribute carrying a second identifier, and may also refer to a high level and a low level, respectively.
And step S106, controlling the polarity of the CAN transceiver to be matched with the polarity of the CAN communication bus according to the attribute of the chip selection signal.
And when the first attribute and the second attribute are respectively a high level and a low level, executing corresponding control according to the levels.
Preferably, the acquiring the attributes of the chip select signal includes: the level of the chip select signal is obtained. Controlling the polarity matching of the CAN transceiver and the CAN communication bus according to the attribute of the chip selection signal comprises the following steps: and controlling the polarity of the CAN transceiver and the CAN communication bus to be matched according to the level of the chip selection signal.
Optionally, before controlling the CAN transceiver to match the polarity of the CAN communication bus according to the level of the chip select signal, the method further includes: it is detected whether network master control data is received. The polarity matching of the CAN transceiver and the CAN communication bus according to the level control of the chip selection signal comprises the following steps: if the network master control data is not received within the preset time, controlling the level of the chip selection signal to be reverse; and controlling the polarity matching of the CAN transceiver and the CAN communication bus according to the chip selection signal after the level inversion.
Fig. 2 is a flowchart of a CAN communication polarity control method according to a second embodiment of the present invention.
The method of this embodiment may include the steps of:
step S202, detecting whether network master control data is received.
The network master control data may be data sent by a network master controller, for example, data sent by an external unit in a multi-connected air conditioning unit.
In step S204, the level of the chip select signal is acquired.
The order of this step and step S202 may be arbitrary.
In step S206, if it is detected that the network master control data is not received within the preset time, the level of the control chip selection signal is reversed.
And step S208, controlling the polarity of the CAN transceiver to be matched with the polarity of the CAN communication bus according to the chip selection signal after the level inversion.
Optionally, the level of the chip select signal is a default level, and at the default level, the default CAN communication polarity of the network slave machine is matched with the default CAN communication polarity of the network master machine.
Optionally, after detecting whether the network master control data is received, the method further includes: judging whether the continuous time for which the network master control data are not received is less than the preset time or not; and if the continuous time for which the network master control data is not received is less than the preset time, keeping the level of the chip selection signal unchanged.
Further, after controlling the polarity of the CAN transceiver and the CAN communication bus to match according to the level of the chip select signal, the method further comprises: detecting whether the CAN communication has a fault; and if the CAN communication is detected to have a fault, continuously detecting whether network master control data are received.
Fig. 3 is a flowchart of a CAN communication polarity control method according to a third embodiment of the present invention.
As shown in fig. 3, as known from the working principle of the multi-connected air conditioning unit shown in fig. 4 and the CAN communication polarity switching circuit shown in fig. 5, the CAN communication polarity switching may be implemented by changing the CS level of the chip select signal, and as shown in the figure, the CAN communication non-polarity software control method may include: after the power-on initialization is completed, the CAN communication polarity of the network slave machine CAN be defaulted by setting the default CAN communication polarity, for example, setting the level of a chip selection signal CS, under the communication polarity, if the data of the network master control machine is received, the data is matched with the communication polarity of the network master control machine, the communication polarity switching action is not required to be executed, and the network is normally communicated; if the data of the network main control computer are not received, when the continuous time of the data which are not received is less than the communication polarity switching threshold value, the level of the chip selection signal CS is kept unchanged, otherwise, the level of the chip selection signal CS is controlled to be reversed, the communication polarity switching action is executed, then if the data of the network main control computer exist, the communication polarity matching with the network main control computer is determined, the communication polarity switching action is not executed any more, and if the data of the network main control computer do not exist, the process is repeated; after the polarity matching with the network master control communication is determined, if a network communication fault occurs, the judgment of the communication polarity switching action needs to be executed again.
The method of the embodiment of the invention CAN be a circuit with CAN communication polarity switching and a software control method, and the network slave machine CAN realize the automatic switching of the CAN communication polarity of the network slave machine, thereby achieving the aim of no polarity of CAN communication.
The embodiment of the invention provides a CAN communication polarity control circuit and system and a multi-connected air-conditioning system. The CAN communication polarity control circuit, the system and the multi-connected air conditioning system CAN be used for controlling the communication polarity in the CAN communication system.
In one embodiment of the invention, the CAN communication polarity control circuit, the CAN communication polarity control system and the multi-connected air conditioning system comprise a chip selection signal receiving end, a switch control tube and a CAN transceiver.
The chip select signal receiving end is configured to receive a chip select signal, where the chip select signal is a signal for providing to the switch control pipe, so that the switch control pipe may perform corresponding switch control according to the signal, where the chip select signal has different attributes, and the different attributes may carry different identification information, for example, when the chip select signal carries first information, the attribute of the chip select signal is a first attribute, and when the chip select signal carries second information, the attribute of the chip select signal is a second attribute. Alternatively, the chip select signal may be a signal having different levels, for example, the chip select signal may be high level or low level.
The switch control tube is connected with the chip selection signal receiving end. The CAN transceiver is connected with the switch control tube, connected with the CAN communication bus and used for being matched with the polarity of the CAN communication bus according to the attribute of the chip selection signal.
In this embodiment, the CAN communication polarity control circuit and system and the multi-connected air conditioning system including the following structures are adopted: a chip selection signal receiving end for receiving a chip selection signal; the switch control tube is connected with the chip selection signal receiving end; and the CAN transceiver is connected with the switch control tube, the CAN communication bus and the chip selection signal and is used for matching the polarity of the CAN communication bus according to the attribute of the chip selection signal, so that the technical effect of automatic switching of the CAN communication polarity is realized.
Alternatively, as described above, the chip select signal may be a signal having different levels, and thus the CAN transceiver is configured to match the polarity of the CAN communication bus according to the level of the chip select signal. In the following embodiments, the chip select signal is described by taking a high level and a low level as an example.
Optionally, the switch control tube comprises: a first switching control tube Q1 and a second switching control tube Q2. The CAN transceiver comprises a first CAN transceiver U1 and a second CAN transceiver U2, the first CAN transceiver U1 is connected with a first switch control tube Q1, and the second CAN transceiver U2 is connected with a second switch control tube Q2.
In an embodiment of the present invention, as shown in the figure, the CAN communication polarity control circuit may further include: and the level inverter U4 is arranged between the first switch control tube Q1 and the second switch control tube Q2.
Optionally, the control terminal of the first switch control tube Q1 is connected to the chip select signal receiving terminal, and the first switch control tube Q1 is further connected to the power port of the first CAN transceiver U1. The control end of the second switch control tube Q2 is connected to the chip select signal receiving end, and the second switch control tube Q2 is further connected to the power port of the second CAN transceiver U2.
Optionally, the CAN communication bus comprises a first CAN signal line and a second CAN signal line. The first CAN signal interface CAN _ H of the first CAN transceiver U1 and the second CAN signal interface CAN _ L of the second CAN transceiver U2 are connected to the first CAN signal line. The second CAN signal interface CAN _ L of the first CAN transceiver U1 and the first CAN signal interface CAN _ H of the second CAN transceiver U2 are connected to the second CAN signal line.
Optionally, the level of the chip select signal is a first level or a second level, wherein when the level of the chip select signal is the first level, the first switch control transistor Q1 is in a conducting state, the first CAN transceiver U1 is in a power-up state, and when the level of the chip select signal is the second level, the second switch control transistor Q2 is in a conducting state, and the second CAN transceiver U2 is in a power-up state.
The embodiment of the invention also provides a CAN communication system which CAN comprise any one of the CAN communication polarity control circuits provided by the embodiment of the invention.
A CAN communication system according to an embodiment of the present invention is described below, and the CAN communication system includes: a CAN communication bus; CAN communication polarity control circuit, wherein, CAN communication polarity control circuit includes: the chip selection signal receiving end is used for receiving a chip selection signal, wherein the level of the chip selection signal is a first level or a second level; the switch control tube is connected with the chip selection signal receiving end; and the CAN transceiver is connected with the switch control tube, connected with the CAN communication bus and used for matching the polarity of the CAN communication bus according to the level of the chip selection signal.
Optionally, the CAN communication bus comprises a first CAN signal line and a second CAN signal line. The switch control tube comprises a first switch control tube Q1 and a second switch control tube Q2. The CAN transceiver includes: the first CAN transceiver U1 is connected with the first switch control tube Q1; and the second CAN transceiver U2 is connected with the second switch control tube Q2. The first CAN signal interface CAN _ H of the first CAN transceiver U1 and the second CAN signal interface CAN _ L of the second CAN transceiver U2 are connected to the first CAN signal line, and the second CAN signal interface CAN _ L of the first CAN transceiver U1 and the first CAN signal interface CAN _ H of the second CAN transceiver U2 are connected to the second CAN signal line.
Optionally, the CAN communication system further comprises: and the microprocessor MCU is connected with the CAN transceiver and is used for outputting the chip selection signal to a chip selection signal receiving end.
According to another aspect of the embodiment of the invention, a multi-connected air conditioning system is further provided, and the multi-connected air conditioning system comprises any one of the CAN communication polarity control circuits provided by the invention. Fig. 4 is a schematic view of a multi-connected air conditioning unit according to an embodiment of the present invention, which illustrates a configuration diagram of a multi-connected air conditioning unit (i.e., a system) of the present invention.
According to another aspect of the embodiments of the present invention, a CAN communication polarity control device is further provided, where the CAN communication polarity control device may be configured to execute the CAN communication polarity control method provided in the embodiments of the present invention, and the CAN communication polarity control method in the embodiments of the present invention may also be executed by the CAN communication polarity control device. The CAN communication polarity control device comprises a receiving unit, an acquiring unit and a control unit.
A receiving unit for receiving a chip select signal; the acquisition unit is used for acquiring the attribute of the chip selection signal; and the control unit is used for controlling the polarity matching of the CAN transceiver and the CAN communication bus according to the attribute of the chip selection signal.
Furthermore, the acquisition unit is used for acquiring the level of the chip selection signal, and the control unit is used for controlling the polarity matching of the CAN transceiver and the CAN communication bus according to the level of the chip selection signal.
Optionally, the CAN communication polarity control apparatus further includes: and the first detection unit 40 is used for detecting whether network master control data is received or not before the polarity of the CAN transceiver and the CAN communication bus is controlled to be matched according to the level of the chip selection signal. The control unit includes: the first control module is used for controlling the level reversal of the control selection signal when detecting that the network master control data is not received within the preset time; and the second control module is used for controlling the polarity matching of the CAN transceiver and the CAN communication bus according to the chip selection signal after the level reversal. The situation for this embodiment is shown in fig. 7.
Optionally, the level of the chip select signal is a default level, and at the default level, the default CAN communication polarity of the network slave is matched with the default CAN communication polarity of the network host.
Optionally, the CAN communication polarity control apparatus further includes: and the judging unit is used for judging whether the continuous time for which the network main control data is not received is less than the preset time after detecting whether the network main control data is received. And the keeping unit is used for keeping the level of the chip selection signal unchanged when the continuous time for which the network master control data is not received is less than the preset time.
Optionally, the CAN communication polarity control apparatus further includes: the second detection unit 50 is used for detecting whether the CAN communication has a fault or not after controlling the CAN transceiver to be matched with the polarity of the CAN communication bus according to the level of the chip selection signal; the first detection unit 40 is further configured to continue to detect whether network master control data is received after the second detection unit 50 detects that the CAN communication has a fault. Fig. 8 illustrates the situation of the preferred embodiment.
According to another aspect of the embodiments of the present invention, a CAN communication system is further provided, where the CAN communication system includes a CAN communication bus and any one of the CAN communication polarity control devices provided by the present invention.
According to another aspect of the embodiment of the invention, a multi-connected air conditioning system is further provided, and the multi-connected air conditioning system comprises the CAN communication system provided by the embodiment of the invention.
As shown in fig. 4, a CAN communication network in the multi-connected air conditioning system is formed by connecting an outdoor unit and a plurality of indoor units through communication lines, wherein the outdoor unit serves as a network master controller in the communication network, the CAN communication polarity of the outdoor unit is fixed, the indoor units serve as network slaves in the communication network, and the CAN communication polarity of the indoor units needs to be switched to be consistent with the polarity of the network master controller, so that data interaction between the indoor units and the outdoor units in the entire communication network CAN be guaranteed.
Fig. 5 is a schematic diagram of a CAN communication polarity control circuit according to an embodiment of the present invention. The figure illustrates a preferred embodiment of a CAN communication polarity control circuit.
As shown in fig. 5, the CAN communication polarity switching circuit includes two CAN transceivers U1 and U2, two switch control tubes Q1 and Q2, a level inverter U4, and a CAN communication bus (2wire bus). The working principle of the communication polarity switching circuit is as follows: one path of the chip selection signal CS is connected to the control end of the switch control tube Q2 and is used for controlling whether the Vcc of the CAN transceiver U2 is electrified or not so as to control whether the U2 works normally, and the other path of the chip selection signal CS is connected to the level inverter U4 and is used for negating the level signal of the level inverter U4 and is connected to the control end of the switch control tube Q1 and is used for controlling whether the Vcc of the CAN transceiver U1 is electrified or not so as to control whether the U1 works normally; in the circuit, if one of the CAN communication buses (2wire bus) is a CAN _ H signal line above and one of the CAN _ L signal lines below, the transceiver U2 is correctly matched with the polarity of the communication bus, and if one of the CAN communication buses (2wire bus) is a CAN _ L signal line above and one of the CAN _ L signal lines below is a CAN _ L signal line below, the transceiver U1 is correctly matched with the polarity of the communication bus; when the chip selection signal CS is at a high level, the switch control tube Q2 is switched on, the Vcc of the transceiver U2 is electrified and starts to work normally, after passing through the inverter U4, the signal connected to the control end of the switch control tube Q1 is at a low level, the switch control tube Q1 is cut off, the Vcc of the transceiver U1 is not electrified and cannot work normally, and at the moment, the communication polarity switching circuit is the polarity matched with that of the transceiver U2; when the chip select signal CS is at a low level, the signal connected to the control terminal of the switch control transistor Q2 is at a low level, the switch control transistor Q2 is turned off, the Vcc of the transceiver U2 is not powered and cannot normally operate, after passing through the inverter U4, the signal connected to the control terminal of the switch control transistor Q1 is at a high level, the switch control transistor Q1 is turned on, the Vcc of the transceiver U1 is powered on and starts to normally operate, and at this time, the communication polarity switching circuit is in a polarity matched with that of the transceiver U1.
The above-mentioned serial numbers of the embodiments of the present invention are merely for description and do not represent the merits of the embodiments.
In the above embodiments of the present invention, the descriptions of the respective embodiments have respective emphasis, and for parts that are not described in detail in a certain embodiment, reference may be made to related descriptions of other embodiments.
In the embodiments provided in the present application, it should be understood that the disclosed technology can be implemented in other ways. The above-described embodiments of the apparatus are merely illustrative, and for example, the division of the units may be a logical division, and in actual implementation, there may be another division, for example, multiple units or components may be combined or integrated into another system, or some features may be omitted, or not executed. In addition, the shown or discussed mutual coupling or direct coupling or communication connection may be an indirect coupling or communication connection through some interfaces, units or modules, and may be in an electrical or other form.
The units described as separate parts may or may not be physically separate, and parts displayed as units may or may not be physical units, may be located in one place, or may be distributed on a plurality of units. Some or all of the units can be selected according to actual needs to achieve the purpose of the solution of the embodiment.
In addition, functional units in the embodiments of the present invention may be integrated into one processing unit, or each unit may exist alone physically, or two or more units are integrated into one unit. The integrated unit can be realized in a form of hardware, and can also be realized in a form of a software functional unit.
The integrated unit, if implemented in the form of a software functional unit and sold or used as a stand-alone product, may be stored in a computer readable storage medium. Based on such understanding, the technical solution of the present invention may be embodied in the form of a software product, which is stored in a storage medium and includes instructions for causing a computer device (which may be a personal computer, a server, or a network device) to execute all or part of the steps of the method according to the embodiments of the present invention. And the aforementioned storage medium includes: a U-disk, a Read-Only Memory (ROM), a Random Access Memory (RAM), a removable hard disk, a magnetic or optical disk, and other various media capable of storing program codes.
The foregoing is only a preferred embodiment of the present invention, and it should be noted that, for those skilled in the art, various modifications and decorations can be made without departing from the principle of the present invention, and these modifications and decorations should also be regarded as the protection scope of the present invention.

Claims (7)

1. A CAN communication polarity control circuit, comprising:
a chip selection signal receiving end for receiving a chip selection signal;
the switch control tube is connected with the chip selection signal receiving end; and
the CAN transceiver is connected with the switch control tube, connected with a CAN communication bus and used for matching the polarity of the CAN communication bus according to the attribute of the chip selection signal;
the CAN transceiver is used for matching the polarity of the CAN communication bus according to the level of the chip selection signal;
the switch control tube includes: a first switching control tube Q1; and a second switching control tube Q2, the CAN transceiver including: a first CAN transceiver U1 connected to the first switching control tube Q1; and a second CAN transceiver U2 connected to the second switching control tube Q2;
the CAN communication bus comprises a first CAN signal line and a second CAN signal line, a first CAN signal interface CAN _ H of the first CAN transceiver U1 and a second CAN signal interface CAN _ L of the second CAN transceiver U2 are connected to the first CAN signal line, and a second CAN signal interface CAN _ L of the first CAN transceiver U1 and a first CAN signal interface CAN _ H of the second CAN transceiver U2 are connected to the second CAN signal line.
2. The CAN communication polarity control circuit of claim 1, further comprising:
and a level inverter U4 disposed between the first switch control transistor Q1 and the second switch control transistor Q2.
3. The CAN communication polarity control circuit of claim 1,
the control end of the first switch control tube Q1 is connected to the chip select signal receiving end, the first switch control tube Q1 is also connected to the power port of the first CAN transceiver U1,
the control end of the second switch control tube Q2 is connected to the chip select signal receiving end, and the second switch control tube Q2 is further connected to the power port of the second CAN transceiver U2.
4. The CAN communication polarity control circuit of claim 1, wherein the level of the chip select signal is a first level or a second level, wherein when the level of the chip select signal is the first level, the first switch control transistor Q1 is in a conducting state, the first CAN transceiver U1 is in a powered-up state, and when the level of the chip select signal is the second level, the second switch control transistor Q2 is in a conducting state, and the second CAN transceiver U2 is in a powered-up state.
5. A CAN communication system, comprising:
a CAN communication bus; and
a CAN communication polarity control circuit,
wherein, CAN communication polarity control circuit includes:
the chip selection signal receiving end is used for receiving a chip selection signal, wherein the level of the chip selection signal is a first level or a second level;
the switch control tube is connected with the chip selection signal receiving end; and
the CAN transceiver is connected with the switch control tube, connected with a CAN communication bus and used for matching the polarity of the CAN communication bus according to the level of the chip selection signal;
the CAN communication bus comprises:
a first CAN signal line; and
a second CAN signal line is connected with the first CAN signal line,
the switch control tube includes:
a first switching control tube Q1; and
a second switching control tube Q2 is provided,
the CAN transceiver includes:
a first CAN transceiver U1 connected to the first switching control tube Q1; and
a second CAN transceiver U2 connected with the second switch control tube Q2,
wherein,
a first CAN signal interface CAN _ H of the first CAN transceiver U1 and a second CAN signal interface CAN _ L of the second CAN transceiver U2 are connected to the first CAN signal line,
a second CAN signal interface CAN _ L of the first CAN transceiver U1 and a first CAN signal interface CAN _ H of the second CAN transceiver U2 are connected to the second CAN signal line;
the level of the chip selection signal is a first level or a second level, wherein when the level of the chip selection signal is the first level, the first switch control tube Q1 is in a conducting state, the first CAN transceiver U1 is in a power-on state, and when the level of the chip selection signal is the second level, the second switch control tube Q2 is in a conducting state, and the second CAN transceiver U2 is in a power-on state.
6. The CAN communication system of claim 5, further comprising:
and the microprocessor is connected with the CAN transceiver and is used for outputting the chip selection signal to the chip selection signal receiving end.
7. A multi-connected air conditioning system characterized by comprising the CAN communication polarity control circuit of any one of claims 1 to 4.
CN201710526063.4A 2017-06-30 2017-06-30 CAN communication polarity control circuit and system and multi-connected air conditioning system Active CN107241252B (en)

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