U.S. patent application number 12/926106 was filed with the patent office on 2011-05-26 for air conditioner and communication method thereof.
This patent application is currently assigned to SAMSUNG ELECTRONICS CO., LTD.. Invention is credited to Su Ho Jo, Kwan Joo Myoung, O Do Ryu.
Application Number | 20110120694 12/926106 |
Document ID | / |
Family ID | 43608783 |
Filed Date | 2011-05-26 |
United States Patent
Application |
20110120694 |
Kind Code |
A1 |
Jo; Su Ho ; et al. |
May 26, 2011 |
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.
Inventors: |
Jo; Su Ho; (Seongnam-si,
KR) ; Myoung; Kwan Joo; (Suwon-si, KR) ; Ryu;
O Do; (Suwon-si, KR) |
Assignee: |
SAMSUNG ELECTRONICS CO.,
LTD.
Suwon-si
KR
|
Family ID: |
43608783 |
Appl. No.: |
12/926106 |
Filed: |
October 26, 2010 |
Current U.S.
Class: |
165/237 |
Current CPC
Class: |
F24F 11/56 20180101;
F24F 11/30 20180101; F24F 11/62 20180101; H04L 12/413 20130101 |
Class at
Publication: |
165/237 |
International
Class: |
F24F 11/00 20060101
F24F011/00 |
Foreign Application Data
Date |
Code |
Application Number |
Nov 24, 2009 |
KR |
10-2009-113911 |
Claims
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.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application claims the benefit of Korean Patent
Application No. 2009-0113911, filed on Nov. 24, 2009 in the Korean
Intellectual Property Office, the disclosure of which is
incorporated herein by reference.
BACKGROUND
[0002] 1. Field
[0003] Embodiments relate to an air conditioner in which data
communication is performed between one or more outdoor units and a
plurality of indoor units, and a communication method thereof.
[0004] 2. Description of the Related Art
[0005] An air conditioner is an apparatus that is used to cool or
heat a room. In the air conditioner, a refrigerant is circulated
between an indoor unit and an outdoor unit, and a cooling or
heating operation is performed based on characteristics that the
refrigerant absorbs ambient heat when evaporated and discharges the
heat when liquefied.
[0006] An air conditioner generally has one outdoor unit and one
indoor unit connected to the outdoor unit. However, recently, users
have increasingly demanded a multi-system air conditioner in which
a plurality of indoor units with various shapes and volumes are
connected to one or more outdoor units to perform a cooling or
heating operation in a place having a number of divided spaces,
such as a school or company.
[0007] In general, an RS-485 communication mode, which needs a
smaller number of lines than that in a bidirectional communication
mode and is appropriate for a multi-communication system, is widely
used between an outdoor unit and an indoor unit.
SUMMARY
[0008] Therefore, it is an aspect to provide 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.
[0009] Additional aspects will be set forth in part in the
description which follows and, in part, will be apparent from the
description, or may be learned by practice of the invention.
[0010] In accordance with one aspect, an air conditioner in which
data communication is performed between one or more outdoor units
and a plurality of indoor units includes 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.
[0011] The external interrupt terminal may be connected to a
reception terminal of the microcomputer to detect data on the
communication line.
[0012] The microcomputer may occupy the communication line if no
data is present on the communication line, and then transmit the
generated data to the communication line.
[0013] The microcomputer may transmit occupancy data to the
communication line to occupy the communication line.
[0014] The occupancy data may have high and low states alternating
at random.
[0015] The microcomputer may transmit hold data to make a
distinction between the occupancy data and the data to be
transmitted.
[0016] The hold data may be transmitted to the communication line
for a certain time under the condition of assuming a high
state.
[0017] The microcomputer may transmit 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.
[0018] In accordance with another aspect, 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 includes
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.
[0019] The transmitting may include 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.
[0020] The occupying may include transmitting occupancy data to the
communication line to occupy the communication line.
[0021] The occupancy data may have high and low states alternating
at random.
[0022] The transmitting may further include transmitting hold data
to make a distinction between the occupancy data and the data to be
transmitted.
[0023] The hold data may be transmitted to the communication line
for a certain time under the condition of assuming a high
state.
[0024] The determining may include determining presence or absence
of data on the communication line for a predetermined time if the
data to be transmitted is generated.
[0025] In accordance with another aspect, an air conditioner in
which data communication is performed between one or more outdoor
units and a plurality of indoor units includes 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.
[0026] The microcomputer may determine 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.
BRIEF DESCRIPTION OF THE DRAWINGS
[0027] These and/or other aspects will become apparent and more
readily appreciated from the following description of the
embodiments, taken in conjunction with the accompanying drawings of
which:
[0028] FIG. 1 is a schematic block diagram showing the overall
configuration of an air conditioner according to an embodiment;
[0029] FIG. 2 is a block diagram of a data communication unit of an
air conditioner according to an embodiment;
[0030] FIG. 3 is a timing diagram illustrating a Carrier Sensing
Multiple Access/Collision Avoidance (CSMA/CA) algorithm provided in
an air conditioner according to an embodiment;
[0031] FIG. 4A is a view illustrating data detection timing when a
communication line is monitored through a reception terminal of a
microcomputer according to an embodiment;
[0032] FIG. 4B is a timing diagram illustrating erroneous data
detection timing when a communication line is monitored through a
reception terminal of a microcomputer according to an
embodiment;
[0033] FIG. 5A is a view illustrating data detection timing when a
communication line is monitored through an external interrupt
terminal connected to a reception terminal of a microcomputer
according to an embodiment;
[0034] FIG. 5B is a timing diagram illustrating data detection
timing when a communication line is monitored through an interrupt
terminal of a microcomputer according to an embodiment;
[0035] FIGS. 6A to 6C are timing diagrams illustrating data
transmission of a microcomputer according to an embodiment;
[0036] FIG. 7 is a flow chart illustrating a method for
communication using a Carrier Sensing Multiple Access/Collision
Avoidance (CSMA/CA) algorithm when data is generated in an air
conditioner according to an embodiment; and
[0037] FIG. 8 is a flow chart illustrating data transmission of a
microcomputer according to an embodiment.
DETAILED DESCRIPTION
[0038] Reference will now be made in detail to the embodiments,
examples of which are illustrated in the accompanying drawings,
wherein like reference numerals refer to like elements
throughout.
[0039] FIG. 1 is a schematic block diagram showing the overall
configuration of an air conditioner according to an embodiment,
FIG. 2 is a block diagram of a data communication unit of an air
conditioner according to an embodiment, and FIG. 3 is a timing
diagram illustrating a Carrier Sensing Multiple Access/Collision
Avoidance (CSMA/CA) algorithm provided in an air conditioner
according to an embodiment.
[0040] As shown in FIG. 1, an air conditioner includes one or more
outdoor units 10, a plurality of indoor units 20, and a controller
30 to control the outdoor units 10 and indoor units 20. The
controller 30 functions to control the outdoor units 10 and indoor
units 20 connected thereto, so that a system manager may centrally
control the air conditioner by operating the controller 30.
[0041] As shown in FIG. 2, each outdoor unit 10, each indoor unit
20 and the controller 30 each include a microcomputer 12, 22 or 32
to control the entire operation of a corresponding one of each
outdoor unit 10, each indoor unit 20 and the controller 30, and an
RS-485 communication module 14, 24 or 34 to transmit and receive
data in an RS-485 communication mode.
[0042] The microcomputer 12, 22 or 32 controls transmission and
reception of RS-485 communication. For data transmission, the
microcomputer 12, 22 or 32 delivers a transmission enable signal
and transmission data to the RS-485 communication module 14, 24 or
34. For data reception, the microcomputer 12, 22 or 32 delivers a
reception enable signal to the RS-485 communication module 14, 24
or 34 and receives data transmitted from the RS-485 communication
module 14, 24 or 34. On the other hand, the RS-485 communication
mode, which is a communication protocol for a multi-point
communication line, is one of interface protocols for serial
transmission.
[0043] The microcomputer 12, 22 or 32 transmits and receives data
using a Carrier Sensing Multiple Access/Collision Avoidance
(CSMA/CA) algorithm provided to the RS-485 communication mode. The
CSMA/CA algorithm is a technology that, when data to be transmitted
is generated in a device, determines whether a network currently
connected to the device is in use (carrier sense), transmits a
collision avoidance signal for data transmission to each node if
the network is not in use, and transmits the data at a certain time
after transmitting the collision avoidance signal. For example, as
shown in FIG. 3, when data to be transmitted is generated in the
indoor unit 20 or outdoor unit 10, the microcomputer monitors a
communication line for a predetermined time t1 to determine whether
data transmission is being made on the communication line, and
transmits the data if it is determined that no data is present on
the communication line for the predetermined time t1.
[0044] Hereinafter, a detailed description will be given of the
operation of the air conditioner to, when data to be transmitted is
generated in the indoor unit 20, transmit the data using the
CSMA/CA algorithm. This description is similarly applied to the
outdoor unit 10 and the controller 30.
[0045] When data to be transmitted is generated, the microcomputer
22 monitors a communication line for a predetermined time. If it is
determined that no data is present on the communication line for
the predetermined time, the microcomputer 22 transmits occupancy
data. The occupancy data is data that is transmitted to occupy the
communication line, which has high and low states alternating at
random.
[0046] After transmitting the occupancy data for occupancy of the
communication line, the microcomputer 22 transmits hold data. The
hold data is data that is transmitted to the communication line to
make a distinction between the occupancy data and the data to be
actually transmitted. This hold data is transmitted to the
communication line for a certain time under the condition of
assuming a high state.
[0047] After transmitting the hold data, the microcomputer 22
transmits the data to be actually transmitted.
[0048] The RS-485 communication module 24 transmits and receives
data in the RS-485 communication mode. For data transmission, the
RS-485 communication module 24 enters a transmission enable state
in response to a transmission enable signal from the microcomputer
22 and outputs data received from the microcomputer 22 to the
communication line according to a sign. For data reception, the
RS-485 communication module 24 enters a reception enable state in
response to a reception enable signal from the microcomputer 22,
restores a signal inputted from the communication line to original
data and delivers the restored data to the microcomputer 22. On the
other hand, in an aspect of the present invention, the RS-485
communication module 24 may always be in the reception enable
state, so that it may receive data in real time.
[0049] FIG. 4A is a view illustrating data detection timing when a
communication line is monitored through a reception terminal Rx of
a microcomputer according to an embodiment, and FIG. 4B is a timing
diagram illustrating erroneous data detection timing when a
communication line is monitored through a reception terminal Rx of
a microcomputer according to an embodiment.
[0050] When data to be transmitted is generated, the microcomputer
22 monitors a communication line for a predetermined time. The
reception terminal Rx of the microcomputer 22 recognizes data on a
1-byte basis, as shown in FIG. 4A. For this reason, when detecting
data on the communication line, the microcomputer 22 cannot monitor
external data in units shorter than 1 byte. That is, because the
reception terminal Rx of the microcomputer 22 recognizes data on a
1-byte basis, the microcomputer 22, when detecting data on the
communication line through the reception terminal Rx, can recognize
the data on the communication line only in the case where all bits
of a packet (including a start bit S, a parity bit P and an end bit
E) for transmission of 1-byte data are transmitted. In this case, a
collision may occur because the microcomputer 22 cannot monitor
external data of a unit shorter than 1 byte.
[0051] As shown in FIG. 4B, when data of an indoor unit #1 to be
transmitted is generated, the indoor unit #1 monitors a
communication line for a predetermined time t1 to determine whether
data is present on the communication line, and transmits the data
thereof if it is determined that no data is present on the
communication line for the predetermined time t1. Notably, provided
that data of an indoor unit #2 is generated within a time shorter
than a 1-byte data transmission time after the data of the indoor
unit #1 is generated, the data of the indoor unit #1 and the data
of the indoor unit #2 will collide. In detail, if it is determined
that no data is present on the communication line for the
predetermined time t1 after the data of the indoor unit #1 to be
transmitted is generated, the indoor unit #1 transmits the data
thereof. The indoor unit #2 detects data on the communication line
for the predetermined time t1 after the data of the indoor unit #2
to be transmitted is generated. Because all bits of a packet
corresponding to 1 byte among the data transmitted from the indoor
unit #1 are not transmitted to the reception terminal Rx of the
microcomputer 22 of the indoor unit #2 at a data detection
completion time, the indoor unit #2 determines that no data is
present on the communication line, and transmits the data thereof.
As a result, the data transmitted from the indoor unit #1 and the
data transmitted from the indoor unit #2 collide on the
communication line.
[0052] On the other hand, in an aspect, the above-stated data
collision may be avoided by connecting an external interrupt
terminal ExT to the reception terminal Rx of the microcomputer 22,
the method of which will hereinafter be described in detail.
[0053] FIG. 5A is a view illustrating data detection timing when a
communication line is monitored through an external interrupt
terminal ExT connected to a reception terminal Rx of a
microcomputer according to an embodiment of the present invention,
and FIG. 5B is a timing diagram illustrating data detection timing
when a communication line is monitored through an interrupt
terminal ExT of a microcomputer according to an embodiment.
[0054] As shown in FIG. 5A, the external interrupt terminal ExT of
the microcomputer 22 can detect a high or low variation of a
signal. As a result, provided that the interrupt terminal ExT is
connected to the reception terminal Rx of the microcomputer 22, the
microcomputer 22 will be able to detect data on a communication
line by means of a high or low variation, not on a 1-byte
basis.
[0055] As shown in FIG. 5B, when data of an indoor unit #1 to be
transmitted is generated, the indoor unit #1 monitors a
communication line for a predetermined time t1 to determine whether
data is present on the communication line, and transmits the data
thereof if it is determined that no data is present on the
communication line for the predetermined time t1. Notably, even
though data of an indoor unit #2 to be transmitted is generated
within a time shorter than a 1-byte data transmission time after
the data of the indoor unit #1 to be transmitted is generated, the
data of the indoor unit #1 and the data of the indoor unit #2 can
be prevented from colliding, because the indoor unit #2 can detect
data on the communication line on a bit basis. In detail, if it is
determined that no data is present on the communication line for
the predetermined time t1 after the data of the indoor unit #1 to
be transmitted is generated, the indoor unit #1 transmits the data
thereof. The indoor unit #2 detects data on the communication line
for the predetermined time t1 after the data of the indoor unit #2
to be transmitted is generated and, before the data detection is
completed, detects the data transmitted from the indoor unit #1 to
the communication line. If data on the communication line is
detected, the indoor unit #2 does not transmit the data thereof
and, after the lapse of a predetermined time t2, again determines
whether data is present on the communication line. If no data is
detected for the predetermined time t1, the indoor unit #2
transmits the data thereof.
[0056] FIGS. 6A to 6C are timing diagrams illustrating data
transmission of a microcomputer according to an embodiment.
[0057] As shown in FIG. 6A, for data transmission, the
microcomputer 22 transmits a transmission enable signal (outputted
from a terminal TxE) to the RS-485 communication module 24. At the
time that the transmission enable signal is made active, the RS-485
communication module 24 switches to a transmission enable state
(after a time t3). On the other hand, provided that the
microcomputer 22 transmits data to the RS-485 communication module
24 through a transmission terminal Tx thereof before the RS-485
communication module 24 switches to the transmission enable state,
the data will be unable to be transmitted to a communication line.
For this reason, the microcomputer 22 has to transmit data after
the RS-485 communication module 24 switches to the transmission
enable state (after t3). However, the time t3 in which the RS-485
communication module 24 switches to the transmission enable state
is variable because it varies with the type or state of a device.
Also, provided that actual data is transmitted after the lapse of a
sufficient time in which the RS-485 communication module 24 can
switch to the transmission enable state, a communication line
non-occupancy period in which the communication line cannot be
occupied will become longer than the transmission enable state
switching time t3, resulting in a data collision. For example, if,
for the communication line non-occupancy period, a different indoor
unit generates data thereof, determines whether data is present on
the communication line, determines that no data is present on the
communication line and thus transmits the data thereof, a data
collision occurs.
[0058] To solve this, as shown in FIG. 6B, the microcomputer 22
outputs occupancy data within a shortest time after transmitting
the transmission enable signal. The occupancy data includes no
information, and is simply data that is transmitted to occupy the
communication line. The occupancy data has such a form that 0 and 1
(low and high states) alternate at random. By transmitting the
occupancy data in the above manner, the occupancy data is outputted
to the communication line immediately after the transmission enable
state switching time t3 elapses, so that the communication line can
be rapidly occupied.
[0059] As shown in FIG. 6C, the microcomputer 22 transmits hold
data after transmitting the occupancy data while the RS-485
communication module 24 switches to the transmission enable state.
The hold data is data that is transmitted to the communication line
to make a distinction between the occupancy data and the data to be
actually transmitted. This hold data is transmitted to the
communication line for a certain time under the condition of
assuming a high state.
[0060] FIG. 7 is a flow chart illustrating a method for
communication using a Carrier Sensing Multiple Access/Collision
Avoidance (CSMA/CA) algorithm when data is generated in an air
conditioner according to an embodiment.
[0061] As shown in FIG. 7, the microcomputer 22 determines whether
data thereof is generated (S10) and, if the data is generated,
detects data on a communication line (S20). Because the interrupt
terminal ExT is connected to the reception terminal Rx of the
microcomputer 22, the microcomputer 22 can detect data on the
communication line by means of high and low state variations of a
signal.
[0062] Upon determining that data is present on the communication
line, the microcomputer 22 does not transmit the data thereof and
waits for a predetermined time t2 (S30). When the predetermined
time t2 has elapsed, the microcomputer 22 again determines whether
data is present on the communication line (S20).
[0063] On the other hand, if it is determined that no data is
present on the communication line, the microcomputer 22 determines
whether a predetermined time t1 has elapsed (S40). In the case
where it is determined that the predetermined time t1 has not
elapsed, the microcomputer 22 continues to detect data on the
communication line (S20). That is, the microcomputer 22
continuously detects data on the communication line for the
predetermined time t1.
[0064] Then, if it is determined that no data is present on the
communication line for the predetermined time t1 after the data
generation, the microcomputer 22 transmits the data thereof
(S50).
[0065] FIG. 8 is a flow chart illustrating data transmission of a
microcomputer according to an embodiment.
[0066] As shown in FIG. 8, for data transmission, the microcomputer
22 transmits a transmission enable signal to the RS-485
communication module 24. After receiving the transmission enable
signal, the RS-485 communication module 24 switches to a
transmission enable state in which it can transmit data (S100).
[0067] Then, the microcomputer 22 transmits occupancy data to a
communication line within a shortest time after initiating the
transmission of the transmission enable signal to the RS-485
communication module 24 (S110). The occupancy data is data that is
transmitted to occupy the communication line immediately after the
RS-485 communication module 24 switches to the transmission enable
state.
[0068] Then, the microcomputer 22 transmits hold data after
transmitting the occupancy data (S120). The hold data is data that
is transmitted to the communication line to make a distinction
between the occupancy data and the data to be actually transmitted.
This hold data is transmitted to the communication line for a
certain time under the condition of assuming a high state.
[0069] Thereafter, the microcomputer 22 transmits the actual data
(S130).
[0070] As is apparent from the above description, according to an
embodiment, a CSMA/CA algorithm is provided to an RS-485
communication mode, so that information of respective devices of an
air conditioner may be efficiently shared.
[0071] Although a few embodiments have been shown and described, it
would be appreciated by those skilled in the art that changes may
be made in these embodiments without departing from the principles
and spirit of the invention, the scope of which is defined in the
claims and their equivalents.
* * * * *