Air conditioner and communication method thereof

Abstract

An air conditioner in which a Carrier Sensing Multiple Access/Collision Avoidance (CSMA/CA) algorithm is provided on a bidirectional RS-485 communication line, and a communication method thereof. The air conditioner includes an RS-485 communication module to transmit and receive data in an RS-485 communication mode, and a microcomputer to determine presence or absence of data on a communication line when data to be transmitted is generated, occupy the communication line if no data is present on the communication line, and then transmit the generated data to the communication line.

1 . An air conditioner in which data communication is performed between one or more outdoor units and a plurality of indoor units, the air conditioner comprising:
 an RS-485 communication module to transmit data in an RS-485 communication mode; and   a microcomputer to determine presence or absence of data on a communication line through an external interrupt terminal for a predetermined time when data to be transmitted is generated, and transmit the generated data to the communication line through the RS-485 communication module if no data is present on the communication line.   
     
     
         2 . The air conditioner according to  claim 1 , wherein the external interrupt terminal is connected to a reception terminal of the microcomputer to detect data on the communication line. 
     
     
         3 . The air conditioner according to  claim 1 , wherein the microcomputer occupies the communication line if no data is present on the communication line, and then transmits the generated data to the communication line. 
     
     
         4 . The air conditioner according to  claim 3 , wherein the microcomputer transmits occupancy data to the communication line to occupy the communication line. 
     
     
         5 . The air conditioner according to  claim 4 , wherein the occupancy data has high and low states alternating at random. 
     
     
         6 . The air conditioner according to  claim 4 , wherein the microcomputer transmits hold data to make a distinction between the occupancy data and the data to be transmitted. 
     
     
         7 . The air conditioner according to  claim 6 , wherein the hold data is transmitted to the communication line for a certain time under the condition of assuming a high state. 
     
     
         8 . The air conditioner according to  claim 1 , wherein the microcomputer transmits a transmission enable signal to the RS-485 communication module if no data is present on the communication line when the data to be transmitted is generated. 
     
     
         9 . A communication method of an air conditioner in which data communication is performed between one or more outdoor units and a plurality of indoor units, the method comprising:
 determining whether data is present on a communication line, if data to be transmitted is generated; and   transmitting the generated data to the communication line if it is determined that no data is present on the communication line.   
     
     
         10 . The communication method according to  claim 9 , wherein the transmitting comprises occupying the communication line if it is determined that no data is present on the communication line, and then transmitting the generated data to the communication line. 
     
     
         11 . The communication method according to  claim 10 , wherein the occupying comprises transmitting occupancy data to the communication line to occupy the communication line. 
     
     
         12 . The communication method according to  claim 11 , wherein the occupancy data has high and low states alternating at random. 
     
     
         13 . The communication method according to  claim 11 , wherein the transmitting further comprises transmitting hold data to make a distinction between the occupancy data and the data to be transmitted. 
     
     
         14 . The communication method according to  claim 13 , wherein the hold data is transmitted to the communication line for a certain time under the condition of assuming a high state. 
     
     
         15 . The communication method according to  claim 9 , wherein the determining comprises determining presence or absence of data on the communication line for a predetermined time if the data to be transmitted is generated. 
     
     
         16 . An air conditioner in which data communication is performed between one or more outdoor units and a plurality of indoor units, the air conditioner comprising:
 an RS-485 communication module to transmit data in an RS-485 communication mode; and   a microcomputer to determine presence or absence of data on a communication line when data to be transmitted is generated, and transmit the generated data to the communication line through the RS-485 communication module if no data is present on the communication line.   
     
     
         17 . The air conditioner according to  claim 16 , wherein the microcomputer determines presence or absence of data on the communication line through an external interrupt terminal, the external interrupt terminal being connected to a reception terminal of the microcomputer. 
     
     
         18 . The air conditioner according to  claim 17 , wherein the external interrupt terminal of the microcomputer detects a high or low variation of a signal, the microcomputer detecting data on the communication line by means of the high or low variation and not on a 1-byte basis.