Title of Invention
SLAVE SUITABLE FOR ENERGY MANAGEMENT SYSTEMS AND ENERGY
5 MANAGEMENT SYSTEM
Technical Field
[00011
The present invention relates to slaves suitable for energy management systems and
10 energy management systems, and particularly to a slave which is suitable for energy
management systems and functions to transmit meter-reading data containing an
amount of electric energy measured by an energy meter in a facility to an upper
device, and an energy management system.
15 Background Art
[00021
In the past, there has been proposed a remote measurement system configured such
that energy meters measure energy consumptions in facilities and a master (master
terminal) obtains measurement results as meter-reading data from slaves (slave
20 terminals) attached to the energy meters (see document 1 [JP 2011-250301 A]).
[00031
In the system disclosed in document 1, the master communicates with an upper
server (upper aggregation server) through a communication network. The upper
25 server may be operated by an electric power company. The master obtains the
meter-reading data of the individual energy meters from the slaves, aggregates to
form meter-reading information, and sends the meter-reading information to the
upper server. Thus, the system enables remote meter-reading.
30 [OOO~]
In the system disclosed in document 1, communication between the slave and an
upper device (e.g., the master and the upper server) is performed by power line
communication using distribution lines as communication paths. If the power line
- 1 -
communication is not available, wireless communication is used.
IE, [00051
Document 1 also discloses that, in a situation where nodes (slaves and upper devices)
5 are not arranged adjacent to each other, communication between the nodes is
established by way of additional devices relaying wireless communication. For
example, when maintenance terminals that are used for maintenance and inspection
and perform wireless communication with the slaves and the upper devices are used
as relay devices, communication paths between the slaves and the upper devices are
10 ensured.
[0006l
Recently, there has been proposed that the slave attached to the energy meter is
configured to communicate with the electric appliance used in the facility in addition
15 to the upper device. This configuration allows the electric appliance to visually
indicate the energy consumption of the facility by displaying the measurement result
of the energy meter, for example. Further, the configuration allows the electric power
company to control the electric appliance by signals for the purpose of suppressing the
peak of the energy demand (i.e., peak cut).
20
[00071
However, the slave has at least the function of communicating with the upper device
and the function of communicating with the maintenance terminal used for
maintenance and inspection, and hence to add the function of communicating with the
25 electric appliance in the facility to the slave, three or more communication interfaces
are necessary. This may cause increases in size and cost of the slave. Especially, such
increases in size and cost of the slave caused by addition of the function of
communicating with the electric appliance are not preferable for a user who does not
use the electric appliance capable of communicating with the slave.
30
Summary of Invention
[00081
In view of the above insufficiency, the present invention has aimed to propose a slave
for energy management systems and an energy management system which can allow
the slave to communicate with not only an upper device but also an electric appliance
e used in a facility and yet can reduce increases in size and cost of the slave as possible.
5 [00091
The slave suitable for energy management systems of the first aspect in accordance
with the present invention is a slave suitable for energy management systems for
collecting, from an energy meter for measuring an amount of electric energy supplied
from a power source to a predetermined place through a distribution line,
10 meter-reading data containing the amount of electric energy. The slave includes a
first interface unit, a second interface unit, a third interface unit, and a controller.
The first interface unit is configured to communicate with an upper device. The
second interface unit is configured to communicate with an electric appliance installed
in the predetermined place. The third interface unit is configured to communicate
15 with a communication terminal. The controller has: a function of obtaining the
meter-reading data from the energy meter; a function of controlling the first interface
unit to send the meter-reading data to the upper device; and a function of controlling
the third interface unit to send the meter-reading data to the communication terminal.
The second interface unit and the third interface unit each are configured to perform
20 wireless communication using an electric wave. The second interface unit and the
third interface unit are configured to use the same protocol.
100 101
According to the slave suitable for energy management systems of the second aspect
25 in accordance with the present invention, depending on the first aspect, the protocol
used by the second interface unit and the third interface unit is a protocol defining a
plurality of channels different from each other. The second interface unit and the
third interface unit are configured to perform wireless communication by use of
different communication channels. The different communication channels are selected
30 from the plurality of channels so that interference between an electric wave from the
second interface unit and an electric wave from the third interface unit does not occur.
According to the slave suitable for energy management systems of the third aspect in
accordance with the present invention, depending on the first or second aspect, the
@ first interface unit is connected to the upper device through the distribution line. The
first interface unit is configured to perform power line communication with the upper
5 device through the distribution line.
[00121
According to the slave suitable for energy management systems of the fourth aspect in
accordance with the present invention, depending on the third aspect, the energy
10 meter is connected to the power source through a transformer configured to adjust
electricity from the power source to electricity appropriate to the predetermined place.
The distribution line includes a first path between the power source and the
transformer, and a second path between the transformer and the energy meter. The
upper device is connected to the second path. The first interface unit is configured to
15 perform power line communication with the upper device through the second path.
[OO13 1
According to the slave suitable for energy management systems of the fifth aspect in
accordance with the present invention, depending on the first or second aspect, the
20 first interface unit is configured to perform wireless communication using an electric
wave with the upper device.
[00141
According to the slave suitable for energy management systems of the sixth aspect in
25 accordance with the present invention, depending on the fifth aspect, the first
interface unit and the second interface unit are configured to use the same protocol.
[00151
According to the slave suitable for energy management systems of the seventh aspect
30 in accordance with the present invention, depending on the fifth aspect, the first
interface unit and the second interface unit are configured to use different protocols.
According to the slave suitable for energy management systems of the eighth aspect in
accordance with the present invention, depending on any one of the first to seventh
@ aspects, the controller includes a channel selector; an interference evaluator; and a
change instructor. The channel selector is configured to select a communication
5 channel to be used for at least one of the wireless communication by the second
interface unit and the wireless communication by the third interface unit, from a
plurality of channels. The interference evaluator is configured to determine whether
interference of electric waves occurs in the communication channel. The change
instructor is configured to provide a change instruction to the channel selector when
10 the interference evaluator determines that the interference occurs. The channel
selector is configured to change the communication channel in response to reception of
the change instruction from the change instructor.
[oo 171
15 According to the slave suitable for energy management systems of the ninth aspect in
accordance with the present invention, depending on the eighth aspect, the controller
includes an identification information holding unit storing identification information
unique to the slave. The channel selector is configured to select from the plurality of
channels an initial channel as a candidate for the communication channel, depending
20 on the identification information stored in the identification information holding unit.
The channel selector is configured to, when receiving the change instruction from the
change instructor, select from the plurality of channels a channel different from the
initial channel, and set the selected channel as the communication channel. The
channel selector is configured to, when not receiving the change instruction from the
25 change instructor, set the initial channel as the communication channel.
100 181
According to the slave suitable for energy management systems of the tenth aspect in
accordance with the present invention, depending on the eighth or ninth aspect, the
30 interference evaluator is configured to determine whether the plurality of channels
includes at least one available channel that does not cause interference of electric
waves. The interference evaluator is configured to, when determining that the
plurality of channels includes the at least one available channel, provide available
channel information identifying the at least one available channel to the change
instructor. The change instructor is configured to select a designated available
eP channel to be set as the communication channel from the at least one available
channel identified by the available channel information, and provide the change
5 instruction indicating the designated available channel to the channel selector. The
channel selector is configured to, when receiving the change instruction from the
change instructor, set the designated available channel indicated by the change
instruction as the communication channel.
10 [00191
According to the slave suitable for energy management systems of the eleventh aspect
in accordance with the present invention, depending on any one of the eighth to tenth
aspects, the controller further includes a communication quality evaluator and a
power instructor. The communication quality evaluator is configured to evaluate a
15 communication quality of the communication channel selected by the channel selector.
The power instructor is configured to set an intensity of an electric wave allocated to
the communication channel to a lower limit of a range of intensities allowing the
communication quality evaluated by the communication quality evaluator to satisfy a
predetermined condition.
20
[00201
According to the slave suitable for energy management systems of the twelfth aspect
in accordance with the present invention, depending on any one of the eighth to
eleventh aspects, the communication channel is a channel to be used for the wireless
25 communication by the third interface unit. The channel selector is configured to select
a second communication channel to be used for the wireless communication by the
second interface unit from a plurality of channels. The third interface unit is
configured to determine whether use of the communication terminal is started. The
change instructor is configured to, when the third interface unit determines that use
30 of the communication terminal is started, provide to the channel selector the change
instruction that indicates, as the second communication channel, a channel that does
not cause interference with a channel used by the communication terminal. The
channel selector is configured to, when receiving the change instruction from the
change instructor, change the second communication channel to the channel indicated
by the change instructor.
5 According to the slave suitable for energy management systems of the thirteenth
aspect in accordance with the present invention, depending on any one of the eighth
to twelfth aspects, each of the plurality of channels is defined by a frequency, a time
slot, or a combination of a frequency and a time slot.
10 too221
According to the slave suitable for energy management systems of the fourteenth
aspect in accordance with the present invention, depending on the ninth aspect, the
identification information is given by the upper device to the slave.
15 [00231
According to the slave suitable for energy management systems of the fifteenth aspect
in accordance with the present invention, depending on any one of the first to
fourteenth aspects, the slave is attached to the energy meter.
20 lo0241
The energy management system of the sixteenth aspect in accordance with the
present invention includes a slave, an upper device, and a communication terminal.
The slave is configured to obtain, from an energy meter for measuring an amount of
electric energy supplied from a power source to a predetermined place through a
25 distribution line, meter-reading data containing the amount of electric energy. The
upper device is configured to obtain the meter-reading data from the slave. The
communication terminal is configured to obtain the meter-reading data from the slave.
The slave includes a first interface unit, a second interface unit, a third interface unit,
and a controller. The first interface unit is configured to communicate with the upper
30 device. The second interface unit is configured to communicate with an electric
appliance installed in the predetermined place. The third interface unit is configured
to communicate with the communication terminal. The controller has: a function of
obtaining the meter-reading data from the energy meter; a function of controlling the
first interface unit to send the meter-reading data to the upper device; and a function
of controlling the third interface unit to send the meter-reading data to the
G communication terminal. The second interface unit and the third interface unit each
are configured to perform wireless communication using an electric wave. The second
5 interface unit and the third interface unit are configured to use the same protocol.
[00251
According to the energy management system of the seventeenth aspect in accordance
with the present invention, depending on the sixteenth aspect, the upper device
10 includes a master connected to the distribution line and an upper server connected to
the master. The master has a function of obtaining the meter-reading data from the
slave, and a function of sending the meter-reading data obtained from the slave to the
upper server. The upper server is configured to store the meter-reading data received
from the master.
15
[0026l
According to the energy management system of the eighteenth aspect in accordance
with the present invention, depending on the sixteenth or seventeenth aspect, the
communication terminal has a function of communicating with the electric appliance.
20
Brief Description of the Drawings
[00271
FIG. 1 is a block diagram illustrating a configuration of an energy management
system in accordance with the first embodiment.
25 FIG. 2 is a system configuration diagram illustrating an operation of the energy
management system in accordance with the first embodiment.
FIG. 3 is a block diagram illustrating a slave used in the energy management system
in accordance with the first embodiment.
FIG. 4 is a schematic configuration diagram illustrating a usage example of the slave
30 in accordance with the first embodiment.
FIG. 5 is a diagram illustrating an example of a setting of initial channels relating to
an example shown in FIG. 4.
FIG. 6 is an explanatory diagram illustrating an operation in a channel setting
procedure in the slave in accordance with the first embodiment.
FIG. 7 is a diagram illustrating an example of a setting of channels relating to the
e example shown in FIG. 4.
FIG. 8 is a diagram illustrating an example of the setting of channels relating to the
5 example shown in FIG. 4.
FIG. 9 is a system configuration diagram illustrating an operation of the energy
management system of the second embodiment.
Description of Embodiments
10 [00281
(FIRST EMBODIMENT)
FIG. 1 shows the energy management system 10 of the present embodiment
configured to collect, from an energy meter 1 for measuring an amount of electric
energy supplied to a predetermined place (in the present embodiment, a facility 100)
15 from a power source (in the present embodiment, a commercial AC power source) 14
through a distribution line 5, meter-reading data containing the amount of electric
energy. Note that, the power source 14 is not limited to a commercial AC power source.
Further, the predetermined place is not limited to the facility 100.
20 [oo291
The energy management system 10 of the present embodiment includes a slave
(communication device) 2, an upper device 30, and a communication terminal
(maintenance terminal) 4.
25 [0030]
The slave 2 is configured to obtain the meter-reading data including the amount of
electric energy from the energy meter 1. For example, as shown in FIG. 3, the slave 2
includes a first interface unit 21, a second interface unit 22, a third interface unit 23,
a meter interface unit 24, and a controller 25.
30
[00311
The first interface unit 21 is used for communication with the upper device 30. In
other words, the first interface unit 21 is configured to communicate with the upper
device 30. For example, the first interface unit 21 is implemented by a combination of
hardware and software necessary to communicate with the upper device 30.
5 The second interface unit 22 is used for communication with an electric appliance 9
installed in the predetermined place (facility 100). In other words, the second
interface unit 22 is configured to communicate with the electric appliance 9. In the
present embodiment, the second interface unit 22 is configured to perform wireless
communication using electric waves with the communication terminal 4. For example,
10 the second interface unit 22 is implemented by a combination of hardware and
software necessary to communicate with the electric appliance 9.
100331
Note that, the electric appliance 9 is not necessarily fixed to the predetermined place.
15 The electric appliance 9 may be portable and be placed on the predetermined place. In
short, it is sufficient that the electric appliance 9 is available in the predetermined
place.
[00341
20 The third interface unit 23 is used for communication with the communication
terminal 4. In other words, the third interface unit 23 is configured to communicate
with the communication terminal 4. The third interface unit 23 is configured to
perform wireless communication using an electric wave with the communication
terminal 4. For example, the third interface unit 23 is implemented by a combination
25 of hardware and software necessary to communicate with the communication
terminal 4.
[00351
The meter interface unit 24 is used for communication with the energy meter 1. In
30 other words, the meter interface unit 24 is configured to communicate with the energy
meter 1. For example, the meter interface unit 24 is configured to perform near field
communication using infrared as transmission medium with the energy meter 1. For
example, the meter interface unit 24 is implemented by a combination of hardware
and software necessary to communicate with the energy meter 1.
The controller 25 has a function of obtaining the meter-reading data from the energy
5 meter 1. Especially, the controller 25 communicates with the energy meter 1 through
the meter interface unit 24 to obtain the meter-reading data from the energy meter 1.
Further, the controller 25 has a function of controlling the first interface unit 21 to
send the meter-reading data to the upper device 30, and a function of controlling the
third interface unit 23 to send the meter-reading data to the communication terminal
10 4.
Lo0371
The energy meter 1 is connected to the power source 14 through a transformer
(step-down transformer) 6 configured to adjust electricity from the power source14 to
15 electricity appropriate to the predetermined place (facility 100). The distribution line
5 includes a distribution line (first path) 501 between the power source 14 and the
transformer 6, and a distribution line (second path) 502 between the transformer 6
and the energy meter 1.
20 [00381
The upper device 30 is connected to the second path 502. The upper device 40 includes
a master 3 connected to the distribution line 5 (the second path 502) and an upper
server 8 connected to the master 3.
25 Coo391
The master 3 has a function of obtaining the meter-reading data from the slave 2, and
a function of sending the meter-reading data obtained from the slave 2 to the upper
server 8.
30 [00401
The upper server 8 is configured to store the meter-reading data received from the
master 3.
[00411
The communication terminal 4 has a function of obtaining the meter-reading data * from the slave 2, and a function of communicating with the electric appliance 9.
5 [00421
Hereinafter, the energy management system of the present embodiment is described
in more detail. As shown in FIG. 1, the energy management system 10 of the present
embodiment includes the slave 2 attached to the energy meter 1, the master 3
configured to obtain the meter-reading data of the energy meter 1 from the slave 2,
10 and the maintenance terminal 4 configured to obtain the meter-reading data from the
slave 2. Note that, the phrase "the slave 2 is attached to the energy meter 1" means
that the slave 2 and the energy meter 1 are installed as a single device. It is
preferable that the slave 2 and the energy meter 1 are accommodated in the same
casing, but the slave 2 and the energy meter 1 may be accommodated in different
15 casings.
[00431
In the following example, the facility 100 is one of dwelling units in a condominium.
However, the facility 100 is not limited to such a dwelling unit, but may be a
20 residence, an office, or a factory.
LO0441
The energy meter 1 is connected to the distribution line 5 for transmitting commercial
electricity from the electric power company (electric power supplier). The energy
25 meter 1 is to measure an amount of energy consumed in the facility 100. The energy
meter 1 constitutes a so-called smart meter together with the slave 2. The
meter-reading data are transmitted to the electric power companies through
communication between the master 3 and the slave 2 each connected to the
distribution line 5, and thus the remote meter-reading or the like may be achieved. In
30 this regard, the meter-reading data contains at least an amount of energy over a
predetermined period of time measured by the energy meter 1 (i.e., an amount of
energy consumed in the facility 100).
P642084
too451
The communication between the slave 2 and the master 3 is achieved by the power
e line communications (PLC) using the distribution line 5 as the transmission medium.
Hence, a first communication path 11 using the distribution line 5 (the second path
5 502) on the upstream side of the energy meter 1 as a transmission medium is formed
between the slave 2 and the master 3. The slave 2 performs the power line
communications with the master 3 through the first communication path 11, and
thereby sends the meter-reading data to the master 3. Further, the slave 2 has the
functions of communicating with the maintenance terminal 4 and the electric
10 appliance 9 used in the facility 100, in addition to the function of communicating with
the master 3, and this is described in detail below.
[00461
In this regard, the slave 2 includes the first interface unit 21 configured to
15 communicate with the master 3, the second interface unit 22 configured to
communicate with the electric appliance 9, and the third interface unit 23 configured
to communicate with the maintenance terminal 4.
I00471
20 The first interface unit 21 is configured to perform power line communication with the
master 3 through the first communication path 11 using the distribution line 5 on the
upstream side of the energy meter 1 as the transmission medium, as described above.
Further, the second interface unit 22 is configured to perform bidirectional wireless
communication with the electric appliance 9, that is one of electric appliances used in
25 the facility 100 and has a communication function, through the second communication
path using an electric wave as a transmission medium. The third interface unit 23 is
configured to perform bidirectional wireless communication with the maintenance
terminal 4 through the third communication path 13 using an electric wave as a
transmission medium.
3 0
[00481
Each of the first interface unit 21, the second interface unit 22, and the third interface
unit 23 sends and receives a packet including a header, a payload, and a trailer. The
header includes information for identifying channels individually set to the first
communication path 11, the second communication path 12, and the third
Q communication path 13. For example, the channels allocated to the individual
communication paths are frequencies for transmitting information. Time slots that
5 are time periods obtained by dividing a communication period are also used as
channels for communication. When different channels are allocated to the individual
communication paths, information is transmitted without causing interference of
different communication paths.
lo [00491
Further, the slave 2 includes the meter interface unit 24 for obtaining the
measurement result from the energy meter 1, and the controller 25 for controlling
each unit. In this regard, the controller 25 includes, as a main component, a device
such as a microcomputer including a processor operating in accordance with a
15 program, and implements various functions by executing predetermined programs.
The meter interface unit 24 is designed to be connected to an extension terminal (not
shown) of the energy meter 1 through wires, for example. Thus, the meter interface
unit 24 can send data to the energy meter 1 and receive data from the energy meter 1.
Note that, the meter interface unit 24 is not necessarily configured to be connected to
20 the energy meter 1 in a wired manner. The meter interface unit 24 may be configured
to perform wireless communication with the energy meter 1. Alternatively, the meter
interface unit 24 may be configured to read out the measurement result by image
processing on images of an indicator of the energy meter 1 taken by a camera (not
shown).
25
[00501
In summary, the slave 2 uses the meter interface unit 24 to obtain the measurement
result of the energy meter 1, and uses the first interface unit 21 to send the obtained
measurement result as the meter-reading data to the master 3 through the first
30 communication path 11. Further, the slave 2 uses the second interface unit 22 to send
data to or receive data from the electric appliance 9 through the second
communication path 12 if necessary. The slave 2 uses the third interface unit 23 to
send data to or receive data from the maintenance terminal 4 through the third
communication path 13 if necessary. Note that, the slave 2 may include a storage unit
(not shown) and be configured to temporarily store the meter-reading data obtained
e)
from the energy meter 1 in the storage unit.
5 100511
Commercial electricity is distributed from an electric power substation to the
step-down transformer 6 situated, for example, at a utility pole (not shown) near the
facility 100, and a voltage of the commercial electricity is decreased by the step-down
transformer 6 and then is supplied to the facility 100 through the distribution line 5.
10 Note that, the step-down transformer 6 may be situated beneath the surface of the
ground, or may be housed in a metal casing situated above the surface of the ground.
100521
The master 3 is situated in a vicinity (e.g., a utility pole) of the step-down transformer
15 6 for supplying the commercial electricity to the facility 100. The master 3 is
configured to transmit the meter-reading data to the upper server 8 owned by an
electric power company or a service provider of collecting amounts of energy, through
a dedicated line 7 using, for example, an optic fiber. In short, the master 3 obtains the
meter-reading data from at least one of the energy meters 1 of the facilities 100, and
20 transmits the obtained meter-reading data to the upper server 8 through the
dedicated line 7.
[00531
The master 3 includes a lower communication unit 31 configured to communicate with
25 the slave 2, and an upper communication unit 32 configured to communicate with the
upper server 8. The master 3 receives the meter-reading data through the lower
communication unit 31 and sends the meter-reading data to the upper server 8
through the upper communication unit 32. In this regard, the lower communication
unit 31 is connected to the distribution line 5 connected to a secondary side of the
30 step-down transformer 6. The lower communication unit 31 communicates with the
first interface unit 21 of the slave 2 through the first communication path 11 defined
by the distribution line 5. The upper communication unit 32 is connected to the
dedicated line 7. Note that, the master 3 may include a storage unit (not shown) and
P642084
be configured to temporarily store the meter-reading data obtained from the slave 2 in
the storage unit. In a case of a condominium inside which a plurality of step-down * transformers 6 are situated, the master 3 may be connected to the secondary sides of
the step-down transformers 6. In this case, for example, the master 3 is situated in an
5 electric room or a building manager room in a building.
[00541
The upper server 8 is a server computer configured to collect the meter-reading data
from the energy meters 1 of the plurality of facilities 100 in a management area. The
10 upper server 8 constitutes the upper device 30 together with the master 3 configured
to obtain the meter-reading data from at least one of the energy meters 1 of the
facilities 100. In short, the upper device (the master 3 and the upper server 8) 30
performs the power line communication with the first interface unit 21 of the slave 2
through the first communication path 11 defined by the distribution line 5 between
15 the upper device 30 and the slave 2, thereby obtaining the meter-reading data from
the slave 2.
100551
Note that, there may be a management server (not shown) interposed between the
20 master 3 and the upper server 8. The management server is installed in accordance
with a region. In this case, in each region, the management server collects the
meter-reading data from the master 3. The upper server 8 collects the meter-reading
data from the plurality of management servers. Consequently, it is possible to
efficiently collect the meter-reading data of the facilities 100 in the plurality of regions.
25 When the management server exists, the management server is also included in the
upper device 30.
[00561
The electric appliances used in the facility 100 include at least one electric appliance 9
30 having the function of communication with the slave 2. The second interface unit 22 of
the slave 2 performs wireless communication with the electric appliance 9 through the
second communication path 12. Such an electric appliance 9 can display the
measurement result of the energy meter 1 to visually indicate the energy consumption
in the facility 100, and can be controlled by signals from the electric power company to
suppress the peak of the energy demand (i.e., peak cut).
5 As shown in FIG. 1, examples of the electric appliance 9 include first appliances 91
and 92, and a second appliance 93. For example, the first appliances 91 and 92 each
may be configured to display the measurement result (the meter-reading data) of the
energy meter 1. The second appliance 93 may be a HEMS (Home Energy Management
System) device connected to various types of loads in the facility 100. Additionally, in
10 the instance shown in FIG. 1, the first appliance 92 communicates with the slave 2 by
way of a relay 94. Hence, a combination of the first appliance 92 and the relay 94
constitutes an electric appliance 9. Moreover, the second appliance 93 communicates
with the slave 2 by way of a measurement unit 95 situated in a distribution circuit
board 90, and therefore a combination of the second appliance 93 and the
15 measurement unit 95 constitutes an electric appliance 9. Note that, the measurement
unit 95 alone may be used as an electric appliance 9.
[00581
Each of these electric appliances 9 includes a wireless communication unit 901 for
20 implementing the function of communicating with the slave 2. The first appliance 91
uses its wireless communication unit 901 to perform direct wireless communication
with the second interface unit 22 of the slave 2. The first appliance 92 uses its
wireless communication unit 901 to perform wireless communication with the second
interface unit 22 of the slave 2 by way of the wireless communication unit 901 of the
25 relay 94. The measurement unit 95 uses its wireless communication unit 901 to
perform direct wireless communication with the second interface unit 22 of the slave 2,
and also uses its wireless communication unit 901 to perform wireless communication
with the wireless communication unit 901 of the second appliance 93.
30 [00591
Each of the first appliances 91 and 92 may have a function such as a function of
displaying information such as the meter-reading data received from the slave 2 on a
display (not shown) and a function of displaying such information on a housing
information board or a television set in the facility 100. The second appliance 93 has a
function of sending information such as power consumption information of loads to
Q the electric power company by way of the slave 2, and of controlling the loads, for
example. The measurement unit 95 has a function of measuring an amount of
5 consumed energy for each branch circuit. In response to reception of a signal for peak
cut from the slave 2, the measurement unit 95 sends, based on current amounts of
consumed energy of the individual branch circuits, a signal for controlling the loads,
to the second appliance 93. Consequently, the second appliance 93 can control the
loads based on the signal from the electric power company in order to suppress the
10 peak of energy demand (peak cut).
[0060]
Note that, each of the first appliances 91 and 92 may have a function of
communicating with the second appliance 93 to change various settings of the second
15 appliance 93. In this case, a content of control on a load by the second appliance 93
can be determined by use of the first appliances 91 and 92.
[00611
The maintenance terminal 4 is carried by a worker of an electric power company.
20 Generally, the maintenance terminal 4 is used for maintenance and inspection of the
energy meter 1 and the slave 2. Additionally, in the energy management system 10 of
the present embodiment, the maintenance terminal 4 is used in meter-reading
operation (so-called, on-site meter-reading) by a worker at a site (i.e., the facility 100).
For example, the worker carrying the maintenance terminal 4 operates the
25 maintenance terminal 4 to communicate with the slave 2 at the facility 100, and thus
allows the maintenance terminal 4 to read out the measurement result (the
meter-reading data) of the energy meter 1.
[0062l
30 The maintenance terminal 4 includes a wireless communication unit 41 configured to
communicate with the slave 2, a manual interface unit 42 configured to receive a
manual input from a person, a display unit 43 configured to display various types of
information, and a storage unit 44 configured to store information such as the read
out meter-reading data. Consequently, the maintenance terminal 4 performs direct
wireless communication with the third interface unit 23 of the slave 2 by use of the
@ wireless communication unit 41 in response to the manual input to the manual
interface unit 42. As a result, the maintenance terminal 4 can display the read-out
5 meter-reading data and the like on the display unit 43, and also store the read out
meter-reading data in the storage unit 44. Additionally, according to the maintenance
terminal 4, it is possible to perform maintenance, inspection, change of various
settings of the energy meter 1 and the slave 2, by use of the manual interface unit 42
and the display unit 43.
10
100631
Note that, the maintenance terminal 4 is used for the purpose of meter-reading,
maintenance, and inspection, by the worker of the electric power company at the site
(facility 100). Hence, the communication between the maintenance terminal 4 and the
15 slave 2 can be implemented by near field communication for a short distance of
several meters. Further, the maintenance terminal 4 identifies the slave 2 by use of
information (e.g., a meter number) preliminarily allocated to the energy meter 1 to
identify the energy meter 1. In a case where the maintenance terminal 4 tries to
communicate with the slave 2 of the desired facility 100, the maintenance terminal 4
20 does not accidentally communicate with the slave 2 of the adjacent facility 100, for
example.
100641
The border of the responsibility between the electric power company and residents of
25 the facility 100 is at the energy meter 1. Accordingly, the electric power company is
responsible for managing the master 3, the maintenance terminal 4, the dedicated
line 7, the upper server 8, the first communication path 11, and the third
communication path 13, and the residents of the facility 100 are responsible for
managing the electric appliance 9 and the second communication path 12. The first
30 communication path 11 is included in an information transmission route (so-called, an
A-route) between the energy meter 1 and the electrical power company. The second
communication path 12 is included in an information transmission route (so-called, a
B-route) enabling directly obtaining information from the energy meter 1.
[00651
ab In the slave 2 of the energy management system 10 of the present embodiment, the
second interface unit 22 configured to communicate with the electric appliance 9 and
5 the third interface unit 23 configured to communicate with the maintenance terminal
4 perform wireless communication by use of the same protocol. In other words, the
second interface unit 22 and the third interface unit 23 each are configured to perform
wireless communication using electric waves. The second interface unit 22 and the
third interface unit 23 are configured to use the same protocol.
10
[00661
The protocols for the second interface unit 22 and the third interface unit 23 are made
same so that the second interface unit 22 and the third interface unit 23 communicate
through the second communication path 12 and the third communication path 13
15 using electric waves respectively but use the same frequency band and the same
modulation scheme.
[00671
For example, the second interface unit 22 and the third interface unit 23 communicate
20 with the electric appliance 9 and the maintenance terminal 4 with the 920 MHz band
for specified low power radio stations, respectively. The second interface unit 22 and
the third interface unit 23 are used for communication in the near filed of the facility
100, and the transmission power of each of the second interface unit 22 and the third
interface unit 23 is set to 20 mW, for example.
2 5
[00681
When the protocols (e.g., the frequency bands and the modulation schemes) used in
the different communication paths are same and the same channel (e.g., a frequency
and a time slot) is used, interference between the different communication paths is
30 likely to occur.
[00691
In view of this, the second interface unit 22 and the third interface unit 23 use the
same protocol, but perform wireless communication by using different channels so
that the second communication path 12 and the third communication path 13 are
@ isolated from each other.
5 [00701
In summary, a protocol defining (having) a plurality of channels different from each
other is used in the second interface unit 22 and the third interface unit 23. The
second interface unit 22 and the third interface unit 23 are configured to perform
wireless communication by use of different communication channels. The different
10 communication channels are selected from the plurality of channels so that
interference between an electric wave from the second interface unit 22 and an
electric wave from the third interface unit 23 does not occur. Note that the phrase
"interference does not occur" is intended to be interpreted as that interference does
not occur in a strict sense, or that interference does not occur substantially.
15
[00711
It is sufficient that the second interface unit 22 and the third interface unit 23 are
configured to perform wireless communication through communication paths using
electric waves, by use of the same protocol. Hence, various types of protocols are
20 available in addition to the protocol using the 920 MHz band described above. For
example, a desired standard such as Wi-Fi (registered trademark), ZigBee (registered
trademark), and Bluetooth (registered trademark) is available for the second interface
unit 22 and the third interface unit 23.
25 Lo0721
As described above, in the slave 2 of the energy management system 10, the second
interface unit 22 and the third interface unit 23 use the same protocol, and thus the
second interface unit 22 and the third interface unit 23 can be constituted by a single
communication module 26.
30
LO0731
In summary, the second interface unit 22 and the third interface unit 23 are realized
by the single communication module 26. Thus, the slave 2 can communicate with the
electric appliance 9 and the maintenance terminal 4 by use of the single
communication module 26. Note that, whether the communication module 26
Q1 functions as the second interface unit 22 or the third interface unit 23 can be
determined by instructions to the communication module 26 from the controller 25,
5 for example.
[00741
The following explanation referring to FIG. 2 is made to an operation of the energy
management system 10 of the present embodiment configured as described above.
10
Lo0751
The slave 2 obtains the meter-reading data measured at regular intervals (e.g., every
1 minute, every 5 minutes, and every 10 minutes) from the energy meter 1 (see FIG.
I), and stores the obtained meter-reading data for a predetermined time period (e.g., a
15 whole day) in the storage unit (not shown).
[0076l
The master 3 can communicate with a plurality of slaves 2 connected to the first
communication path 11 defined by the distribution line 5. The master 3 communicates
20 with each slave 2 through the first communication path 11 and thus periodically
collects the meter-reading data from the plurality of slaves 2 (so-called, routine
meter-reading). For example, when the current time becomes a predetermined point
of time (e.g., midnight) of a day, the master 3 conducts power line communication
with the slave 2 to request the slave 2 to send the meter-reading data, and then
25 receives the meter-reading data from the slave 2 as a reply to such a request, and
stores the meter-reading data in the storage unit (not shown). When the master 3
obtains the meter-reading data from all the slaves 2 connected to the distribution line
5, the master 3 aggregates the obtained meter-reading data to form meter-reading
information, and sends the meter-reading information to the upper server 8 (see FIG.
30 1) through the dedicated line 7 (see FIG. 1).
[00771
The slave 2 also has a function of sending the stored meter-reading data to the
maintenance terminal 4 in response to a request from the maintenance terminal 4. In
other words, the maintenance terminal 4 conducts wireless communication with the
@ slave 2 through the third communication path 13 to request the slave 2 to send the
meter-reading data, and then obtains the meter-reading data by receiving the
5 meter-reading data from the slave 2 as a reply to such a request (on-site
meter-reading). In a case where the routine meter-reading by the master 3 is
incomplete, the worker can perform the on-site meter-reading by use of the
maintenance terminal 4, and therefore the missing meter-reading data can be
obtained.
10
[00781
The maintenance terminal 4 also has a function of communicating with the electric
appliance 9. That is, the maintenance terminal 4 communicates with the electric
appliance 9 through the third communication path 13, the slave 2, and the second
15 communication path 12. Accordingly, for example, the maintenance terminal 4 can
send instruction data such as changing settings for the electric appliance 9 to the
slave 2 through the third communication path 13, and instruct the slave 2 to transfer
the instruction data to the electric appliance 9 through the second communication
path 12. Further, the maintenance terminal 4 can receive reply data from the electric
20 appliance 9 through the slave 2.
[00791
Additionally, the slave 2 performs wireless communication with the electric appliance
9 through the second communication path 12 to send the measurement result of the
25 energy meter 1 to the electric appliance 9 so that the electric appliance 9 can display
an amount of energy used in facility 100, for example. Further, for the purpose of
suppressing the peak of energy demand (peak cut), the slave 2 sends a signal sent
from the electric power company via the master 3, to the electric appliance 9 through
the second communication path 12 so that the operation of the load can be controlled.
3 0
[oosol
The master 3 can collect information of the electric appliance 9 that is obtained by the
slave 2 from the electric appliance 9 through the second communication path 12, by
P642084
sending a request for the information of the electric appliance 9 in the facility 100 to
the slave 2 through the first communication path 11. Further, the maintenance * terminal 4 can send the meter-reading data obtained by the on-site meter-reading to
the slave 2 through the third communication path 13 and make the slave 2 transfer
5 this meter-reading data to the master 3 through the first communication path 11.
100811
Additionally, the maintenance terminal 4 may have a function of sending, to the slave
2, requests for changing communication settings (e.g., frequency bands, modulation
10 schemes, communication levels such as transmission power and receiving sensitivity)
used by the second interface unit 22 and the third interface unit 23. In this instance,
the worker can change the communication settings of the second interface unit 22 and
the third interface unit 23 depending on a condition of communication between the
slave 2 in the facility 100 and the electric appliance 9 and a condition of
15 communication between the slave 2 in the facility 100 and the maintenance terminal
4.
[00821
According to the configuration of the present embodiment described above, the slave 2
20 attached to the energy meter 1 can communicate with the electric appliance 9 used in
the facility 100 in addition to the master 3 and the maintenance terminal.
Consequently, the electric appliance 9 is allowed to visually indicate the energy
consumption of the facility 100 by displaying the measurement result of the energy
meter, for example. Further, the electric appliance 9 can be controlled according to
25 signals from the electric power company for the purpose of suppressing the peak of the
energy demand (i.e., peak cut).
[0083l
In the present embodiment, with regard to the slave 2, the second interface unit 22
30 and the third interface unit 23 uses the same protocol, and therefore the single
communication module 26 can function as both the second interface unit 22 and the
third interface unit 23. Hence, in contrast to a configuration in which the slave 2
includes three or more communication interfaces to have a function of communicating
with the electric appliance 9 in addition to functions of communicating with the
master 3 and the maintenance terminal 4, the slave 2 of the present embodiment can
c be downsized and be produced at a lowered cost. In other words, increases in size and
cost of the slave 2 of the energy management system 10 of the present embodiment is
5 avoided as possible, and nevertheless there is an advantage that the slave 2 can
communicate with the electric appliance 9 used in the facility 100 in addition to the
upper device (master 3) 30.
[00841
10 Further in the present embodiment, the power line communication is used for the
communication between the slave 2 and the master 3, and the wireless
communication is used for each of the communication between the slave 2 and the
maintenance terminal 4 and the communication between the slave 2 and the electric
appliance 9. Hence, traffic of the communication between the slave 2 and the master 3
15 can be isolated from traffic of the other communication. In short, this energy
management system 10 can prevent the communication between the slave 2 and the
master 3 from interfering with the communication between the slave 2 and the
maintenance terminal 4 or the communication between the slave 2 and the electric
appliance 9.
20
[0085]
Furthermore, the slave 2 is attached to the energy meter 1 and thus the energy
management system 10 as described above can be constructed by adding or replacing
the slave 2 without replacing the energy meter 1. In addition, a function added to the
25 energy meter 1 can be changed by replacing only the slave 2, and therefore there is an
advantage that the energy management system 10 has relatively high expandability.
[00861
Note that, in the following explanation for the present embodiment, the phrase
30 "interface unit" is expressed as "IIF" if necessary.
[00871
In the energy management system 10 described above, in order to allow the upper
device 30 to identify one or more slaves 2, it is necessary that identification
information is allocated to individual slaves 2. For example, such identification
information is selected from an address used by the slave 2 to communicate with the
upper device 30, a product number uniquely given to the slave 2, and a MAC address
5 given to the slave 2 with a communication function, for example. It is sufficient that
the identification information is uniquely allocated to the slave 2 managed by the
upper device 30. In summary, it is sufficient that the identification information is
unique with regard to the slaves 2 managed by the master 3. As shown in FIG. 3, the
controller 25 of the slave 2 includes an identification information holding unit 251 for
10 holding the identification information. In other words, the controller 25 includes the
identification information holding unit 251 storing the identification information
unique to the slave 2. For example, the controller 25 is configured to, when receiving
the identification information from the upper device 30, store the received
identification information in the identification information holding unit 251. Note
15 that, the meter I/F' 24 is not shown in FIG. 3.
[oossl
The following explanation is made to an example in which the master 3 issues an
address for communication allocated to the slave 2 managed by the master 3 and this
20 address is used as the identification information. Accordingly, the address used by the
slave 2 to communicate (communicate through the A-route) with the upper device 30
is issued by the master 3. In this example, the master 3 issues the address in response
to reception of an address request from the slave 2, and sends the issued address to
the slave 2 that has sent the address request. Additionally, the master 3 issues the
25 addresses for the slaves 2 in an order of reception of the address request. The address
is an integer indicative of a number of issuance.
[00891
FIG. 4 shows an example in which the slaves 2 are individually situated in dwelling
30 units (facilities 100) of a condominium, and numbers placed on right sides of the
slaves 2 represent the addresses issued by the master 3. Squares illustrated in FIG. 4
schematically represent the dwelling units, and labels "room --" represent dwelling
unit number. In this example, the single master 3 is installed in the condominium,
and collects the meter-reading data from the slaves 2 individually installed in the
dwelling units of the condominium.
5 As described above, the master 3 allocates the addresses to the slaves 2 in the order of
reception of the address requests. As illustrated in FIG. 4, there is no relation
between a physical location of the dwelling unit represented by the dwelling unit
number and the address of the slave 2. As described above, if no relation between the
address and the dwelling unit number is required, a procedure of allocating the
10 addresses to the slaves 2 is facilitated and thus it can be easy to install the system.
[00911
In this regard, a communication area of the slave 2 must be limited so that the slave 2
is allowed to communicate with the electric appliance 9 in the facility associated with
15 the slave 2 and is not allowed to communicate with the electric appliance 9 in a
neighboring facility. Further, an area in which the slave 2 and the maintenance
terminal 4 communicate with each other must be limited so that, in a period in which
the slave 2 communicates with the maintenance terminal 4, the maintenance
terminal 4 is not allowed to communicate with another slave 2. Well known
20 techniques of limiting communication areas may include a technique of selecting
channels used in communication areas, a technique of adjusting either the output
power (transmission power) at the transmission side or the reception sensitivity at the
reception side, and a technique of distributing encryption keys used in communication
areas.
2 5
[00921
The limitation of the communication area may be required for not only a case in which
the second I F 22 and the third I F 23 use electric waves as the transmission media
but also the power line communication using the distribution line 5 as the
30 transmission medium. In the following, the technique of selecting channels is
described, and after that the technique of adjusting either the output power or the
reception sensitivity is described.
[00931
The slave 2 selects channels used in the second I/F 22 and the third I/F 23 from a
Q
plurality of channels in a predetermined selectable range. Note that, normally, the
third I/F 23 is not used. In view of this, it is preferable that the third I/Fs 23 of all the
5 slaves 2 use the same channel and this channel be used by the second I/F 22 while the
third I/F 23 is not used.
[00941
The channel is defined by at least one of a frequency and a time slot. With regard to
10 the slave 2, channels to be used by the second I/F 22 and the third I/F 23 of the slave 2
are defined by parameters in the selectable range selected from various types of
frequencies, various types of time slots, or combinations of various types of
frequencies and various types of time slots. Note that, the channel may be defined by
a frequency, a time slot, or a combination of a frequency and a time slot.
15
[00951
In the slave 2, the controller 25 includes a channel selector 252 configured to select a
channel used by the slave 2 from the plurality of channels in the predetermined
selectable range.
2 0
[0096l
In summary, as shown in FIG. 3, the controller 25 of the slave 2 includes the channel
selector 252 configured to select a communication channel (first communication
channel) to be used for wireless communication (wireless communication by the third
25 interface unit 23) from the plurality of channels. Additionally, the channel selector
252 is configured to designate a communication channel (second communication
channel) to be used for the second wireless communication (wireless communication
by the second interface unit 22). In the present embodiment, the channel selector 252
selects the same channel, as the first communication channel and the second
30 communication channel.
[00971
It is sufficient that the channel selector 252 is configured to select, from the plurality
of channels, a communication channel to be used for at least one of the wireless
communication by the second interface unit 22 and the wireless communication by the
third interface unit 23.
5 [00981
Integers more than 0 associated with the parameters in the aforementioned selectable
range are used as the channels in the present embodiment. There is no intent to limit
the format for representing the channels. However, using integers allows easy
designation of the channels.
10
[00991
Before fixing the channel to be used, the slave 2 performs a prior process of
tentatively setting the channel, and performs a subsequent process of, after
evaluating interference in a case where the communication is performed by use of the
15 channel set in the prior process, changing the channel based on the evaluation result
if necessary. In summary, the slave 2 performs two processes including the prior
process and the subsequent process. In the prior process, the channel (hereinafter
referred to as "initial channel") is tentatively set, and in the subsequent process, the
initial channel is changed appropriately to avoid occurrence of interference.
2 0
[01001
As shown in FIG. 3, the slave 2 includes, in the controller 25, an interference
evaluator 253 configured to evaluate a degree of interference in a case where the
initial channel tentatively set is used, and a change instructor 254 configured to
25 instruct the channel selector 252 to change the channel when there is a possibility of
interference. In short, as shown in FIG. 3, the controller 25 of the slave 2 includes the
interference evaluator 253 and the change instructor 254.
[01011
30 The interference evaluator 253 is configured to determine whether interference of
electric waves occurs in the communication channel. For example, the interference
evaluator 253 calculates an evaluation value representing a degree of interference,
and evaluates the degree of interference through comparison of the evaluation value
with a prescribed threshold.
[0102l
For the evaluation value for evaluating the degree of interference, a received signal
5 strength indication (RSSI), the frequency, the time slot, or an appropriate
combination of these can be used, for example. When the received signal strength
indication is high, interference is likely to occur. Additionally, when a difference
between the frequencies is small or when the time slots are adjacent to each other,
interference also is likely to occur. Hence, by converting such information into
10 numerical values as the evaluation values, indications for evaluating the degree of
interference can be obtained. It is assumed that the evaluation value is determined so
as to be monotonically increased with a change in the degree of interference. In this
case, the interference evaluator 253 compares the evaluation value with the threshold.
When the evaluation value exceeds the threshold, the interference evaluator 253
15 determines that the degree of interference is high and there is need to change the
channel.
The change instructor 254 is configured to provide the change instruction to the
20 channel selector 252 when the interference evaluator 253 determines that the
interference occurs. For example, when the interference evaluator 253 determines
that the change of the channel is necessary (i.e., the evaluation value exceeds the
threshold), the change instructor 254 instructs the channel selector 252 to change the
selected channel. Additionally, the change instructor 254 is configured to not provide
25 the change instruction to the channel selector 252 when the interference evaluator
253 determines that the interference does not occur. For example, when the
evaluation value is less than the threshold in the interference evaluator 253, the
change instructor 254 uses the channel selected by the channel selector 252 for
communication.
30
[O 1041
The channel selector 252 is configured to change the communication channel in
response to reception of the change instruction from the change instructor 254.
[01051
In particular, the channel selector 252 is configured to select from the plurality of
channels the initial channel as a candidate for the communication channel, depending
5 on the identification information stored in the identification information holding unit
251. The channel selector 252 is configured to, when receiving the change instruction
from the change instructor 254, select from the plurality of channels a channel
different from the initial channel, and set the selected channel as the communication
channel. The channel selector 252 is configured to, when not receiving the change
10 instruction from the change instructor 254, set the initial channel as the
communication channel.
[O 1061
In the following, a concrete example of the operation of the slave 2 is described using
15 the case shown in FIG. 4. This example of the operation is only an example, and there
is no intent to limit the operation of the slave 2, and therefore the slave 2 may
perform other alternative operation.
[01071
20 The illustrated instance shows a condition in which the master 3 issues the
identification information for the slave 2 in response to the address request from the
slave 2. The slave 2 holds the identification information issued by the master 3 in the
identification information holding unit 251. In this operation example, the channel
selector 252 selects as the initial channel the channel corresponding to the least
25 significant digit of an integer of two digits held in the identification information
holding unit 251. In the illustrated instance, the identification information (address)
issued under management of the master 3 is of two digits such as "02", "54", ..., "15",
and "23". The master 3 issues the identification information so as not to be same as
the identification information that has already been issued, and therefore the same
30 identification information is not issued under the management area of the master 3.
[o 1081
The channel selector 252 of the slave 2 uses the channel corresponding to the least
significant digit of the identification information as the initial channel, and therefore
the channel corresponding to a number of one digit, that is, "0" to "9" is set to the
initial channel as shown in FIG. 5. In the case of the instance illustrated in FIG. 4,
the same initial channel "04" is given to the room 102 and the room 202 adjacent in
5 the vertical direction, and the same initial channel "05" is given to the room 203 and
the room 303 adjacent in the vertical direction.
[O 1091
Note that, the initial channel is selected by use of the least significant digit of the
10 identification information defined by an integer, but may be selected by use of another
rule. For example, the initial channel may be selected by use of a remainder of
division of the identification information defined by an integer by an appropriate
divider. When the initial channel is selected based on the least significant digit, the
number of selectable channels is 10. Whereas, when the initial channel is selected
15 based on the remainder, the number of selectable channels depends on the value of
the divider.
Lo1 101
As described, there is no relation between the position of the dwelling unit (facility
20 100) and the identification information of the slave 2. Therefore, when the channel is
selected based on the least significant digit of the identification information, the same
channel is set to the slaves 2 installed in the neighboring dwelling units in some cases.
Hence, there is a possibility that the same initial channel is set to the adjacent slaves
2. When the slaves 2 using the same initial channel are installed adjacent to each
25 other, interference is likely to occur in communication.
[Ollll
The slave 2 measures the received signal strength indications of all the channels in
the selectable range in order to detect the initial channel set to another slave 2
30 existing in an area in which the slave 2 can communicate. And, the slave 2 records as
"in-use channel" a channel corresponding to the received signal strength indication
greater than a prescribed threshold. The process of detecting the in-use channel is
performed by the interference evaluator 253. To detect the in-use channel, it is
necessary to measure the received signal strength indication for each channel. Hence,
the interference evaluator 253 sequentially in turn measures the received signal * strength indications of all the channels in the selectable range.
5 [01121
When the in-use channel is same as the channel to be used, interference is likely to
occur. Hence, the interference evaluator 253 of the slave 2 tries to detect another
slave 2 which uses a channel that is one of the detected in-use channels and is same
as the initial channel of the slave 2. In a process of measuring the received signal
10 strength indications of the individual channels, the slave 2 receives the identification
information as well as the channel of another slave 2. For example, the interference
evaluator 253 of the slave 2 receives packets outputted from the other slaves 2 to
evaluate the received signal strength indications, and extracts the identification
information of another slave 2 from the header of the received packet. Consequently,
15 the slave 2 obtains the identification information of another slave 2 that has the same
initial channel as the slave 2 and gives the received signal strength indication greater
than the threshold.
[01131
20 In the example described herein, the identification information of the slave 2 is an
integer. When the same initial channel is set to the two or more slaves 2, the
interference evaluator 253 selects one slave 2 that is allowed to use this initial
channel from the two or more slaves 2 based on whether the identification
information is greater. When two or more other slaves 2 have the same initial channel
25 and give the received signal strength indications greater than the threshold, the
interference evaluator 253 determines whether the identification information is
greater than the other identification information. When the identification information
of the slave 2 is the smallest of the pieces of the identification information of the other
slaves 2, the interference evaluator 253 of the slave 2 allows the slave 2 to continue to
30 use this initial channel as the communication channel. Further, the interference
evaluator 253 of the slave 2 requests the channel selector 252 to change the channel
by use of the change instructor 254 when the identification information of the slave 2
is not the smallest of the pieces of the identification information of the other slaves 2.
[01141
When the interference evaluator 253 intends to request the change instructor 254 to
change the channel, first the interference evaluator 253 tries to detect the channel
5 corresponding to the received signal strength indication equal to or less than the
threshold from the channels in the selectable range. When the received signal
strength indication of the channel is equal to or less than the threshold, it can be
considered that the channel is not used or interference is unlikely to occur even when
the channel is used. Hence, the detected channel is treated as "available channel".
10 When the available channel is detected, the interference evaluator 253 provides
information of the available channel to the change instructor 254. In summary, the
interference evaluator 253 is configured to determine whether the plurality of
channels includes at least one available channel that does not cause interference of
the electric waves. The interference evaluator 253 is configured to, when determining
15 that the plurality of channels includes the available channel, provide available
channel information identifying the at least one available channel to the change
instructor 254. Note that, in some cases, there is a plurality of available channels. In
such cases, the available channel information individually identifies the plurality of
available channels.
2 0
[01151
The change instructor 254 is configured to select a designated available channel to be
set as the communication channel from the at least one available channel identified
by the available channel information, and provide the change instruction indicating
25 the designated available channel to the channel selector 252. For example, the change
instructor 254 instructs the channel selector 252 to change the channel after a lapse
of a waiting time period determined based on the initial channel. The waiting time
period is determined so that the waiting time period is shorter as the number of the
initial channel is smaller (e.g., the waiting time period is given by multiplying a unit
30 time period by the number of the initial channel). When the waiting time period is
determined in such a manner, it is possible to avoid an undesired situation in which
the slaves 2 selecting the different initial channels select the same available channel.
[O 1161
The channel selector 252 is configured to, when receiving the change instruction from
the change instructor 254, set the designated available channel indicated by the
change instruction as the communication channel.
5
to1171
The aforementioned channel selection techniques are collectively illustrated in FIG. 6.
In preprocessing, the channel selector 252 of the slave 2 in question selects the initial
channel corresponding to the least significant digit of the identification information of
10 the slave 2 in question defined by an integer (S11). Thereafter, the interference
evaluator 253 of the slave 2 in question measures the received signal strength
indications of all the channels in the selectable range sequentially in turn (S12),
detects the channel whose received signal strength indication is greater than the
threshold, as the in-use channel, and records the detected channel (S13). Next, the
15 interference evaluator 253 of the slave 2 in question obtains, from the header of the
packet, the identification information of another slave 2 whose in-use channel is same
as the initial channel of the slave 2 in question (S14). When another slave 2 whose
in-use channel is same as the initial channel of the slave 2 in question is present and
interference is likely to be caused by the presence of this slave 2, whether the
20 identification information of this slave 2 is greater than the identification information
of the slave 2 in question is determined (S15).
lo1 181
When the identification information of the slave 2 is minimum (S15: Yes), use of the
25 initial channel is continued (S16). In contrast, when the identification information of
the slave 2 is not minimum (S15: No), the interference evaluator 253 evaluates the
received signal strength indications for all the channels to detect the available
channel (517). When the available channels are detected, after a lapse of the
predetermined waiting time period (S181, the change instructor 254 instructs the
30 channel selector 252 to select, as the channel to be used by the second I&' 22, the
available channel corresponding to the smallest one of the numbers of the detected
available channels (S19). Through the aforementioned manner, the channel to be used
by the second I&' 22 is selected by the channel selector 252, and consequently the
slave 2 starts to operate by use of the selected channel (S20).
@ [01191
Even when the same initial channel is set to two or more slaves 2, the fact that the
5 same initial channel is set cannot be detected, provided that the header of the packet
outputted from any of these slaves 2 cannot be received by another slave 2. When
physical distances between the slaves 2 are relatively long, or there may be partitions
between the slaves 2, the received signal strength indication may be so low that the
slaves 2 cannot recognize the header of the packet from the others. In this case, the
10 comparison of the identification information of the slave 2 is not performed even when
interference is likely to occur.
[01201
In other words, even when the same initial channel is set to two or more slaves 2,
15 provided that the slave 2 can communicate with the electric appliance 9 in the facility
associated with the slave 2 and the maintenance terminal 4 but cannot communicate
with the other slaves 2, the slave 2 can use the initial channel without change.
[01211
20 In view of this, the controller 25 of the slave 2 includes a communication quality
evaluator 255 configured to evaluate a communication quality through test
communication, and a power instructor 256 configured to adjust the output power of
the second I/F' 22 and the output power of the third I&' 23.
25 [01221
The communication quality evaluator 255 is configured to evaluate a communication
quality of the communication channel (first communication channel) selected by the
channel selector 252. For example, the communication quality evaluator 255 is
configured to conduct test communication by use of the communication channel (first
30 communication channel) selected by the channel selector 252 to evaluate the
communication quality (communication quality of the first communication channel) of
the communication path 13 between the slave 2 and the communication terminal 4.
[01231
The power instructor 256 is configured to set an intensity of an electric wave allocated
to the communication channel (first communication channel) to a lower limit of a
range of intensities allowing the communication quality evaluated by the
5 communication quality evaluator 255 to satisfy a predetermined condition. For
example, the power instructor 256 is configured to decrease the intensity of the
electric wave (electric wave according to the communication channel) outputted from
the third interface unit 23 within a range in which the communication quality
(communication quality of the communication path 13) evaluated by the
10 communication quality evaluator 255 fulfills the predetermined condition.
[01241
Additionally, the communication quality evaluator 255 is configured to evaluate a
communication quality of the communication channel (second communication
15 channel) selected by the channel selector 252. For example, the communication
quality evaluator 255 is configured to conduct test communication by use of the
communication channel (second communication channel) selected by the channel
selector 252 to evaluate the communication quality (communication quality of the
second communication channel) of the communication path 12 between the slave 2
20 and the electric appliance 9.
[01251
Also in this case, the power instructor 256 is configured to set an intensity of an
electric wave allocated to the second communication channel to a lower limit of a
25 range of intensities allowing the communication quality (communication quality of the
second communication channel) evaluated by the communication quality evaluator
255 to satisfy a predetermined condition. For example, the power instructor 256 is
configured to decrease the intensity of the electric wave (electric wave according to the
communication channel) outputted from the second interface unit 22 within a range in
30 which the communication quality (communication quality of the communication path
12) evaluated by the communication quality evaluator 255 fulfills the predetermined
condition.
[01261
After the slave 2 obtains the address for communication issued by the master 3 and
the initial channel is set, the slave 2 first performs test communication with the
electric appliance 9 in the facility managed by the slave 2 and test communication
5 with the maintenance terminal 4. Note that, in a process of setting the initial channel
to the slave 2, it is assumed that a person who installs the slave 2 carries the
maintenance terminal 4 and thus the maintenance terminal 4 is present in the
communication area of the slave 2.
10 [01271
The slave 2 conducting the test communication decreases the output power for
transmitting packets with time, and controls the communication quality evaluator
255 to obtain communication statistic information (communication quality) such as a
communication error rate and a retransmission rate with regard to at least one of the
15 second IF 22 and the third I F 23. Additionally, this slave 2 controls the power
instructor 256 to decrease the output power of at least one of the second I/F 22 and
the third I/F 23 down to an allowable lower limit of the range in which the
communication qualities with the electric appliance 9 and the maintenance terminal 4
are kept good.
2 0
[O 1281
As described above, the output power of the slave 2 is decreased down to the allowable
lower limit, and thus interference can be avoided even when the same initial channel
is set to a plurality of slaves 2. Moreover, the slave 2 decreases the output power down
25 to the allowable limit within the range in which the communication quality is kept
good, and therefore the communication quality with the electric appliance 9 in the
facility associated with the slave and the communication quality with the
maintenance terminal 4 can be maintained. As a result, a probability that the slave 2
changes the initial channel is reduced, although the number of selectable channels is
30 limited, the channels can be set so as to avoid interference even when the number of
slaves 2 is greater than the number of channels.
To enable communication between the slave 2 and the electric appliance 9 in the same
facility associated with the slave 2, association (channel setting) between the slave 2
and the electric appliance 9 is necessary. The electric appliance 9 includes two
operation modes of a registration mode in which the channel is set to associate the
5 electric appliance 9 with the slave 2, and a normal mode in which the electric
appliance 9 operates by use of the set channel. For example, in the registration mode,
the electric appliance 9 selects all the channels sequentially in turn until the electric
appliance 9 receives the packet sent periodically from the slave 2.
10 [01301
In one example, the packet sent from the slave 2 includes information for identifying
the energy meter 1 (e.g., a meter number), and a worker inputs the information for
identifying the energy meter 1 into the electric appliance 9. In this example, the
electric appliance 9 compares the information for identifying the energy meter 1 to
15 select the channel of the slave 2 of the facility in which the electric appliance 9 is
installed. Hence, the association between the slave 2 and the electric appliance 9 can
be completed successfully.
[01311
20 In the registration mode, the electric appliance 9 receives packets of all the channels,
and therefore the electric appliance 9 may receive the packet from the slave 2 in
another facility. However, use of the information for identifying the energy meter 1
can prevent association of the electric appliance 9 with the slave 2 in another facility.
When the selection of the channel ends, the electric appliance 9 starts the normal
25 mode and begins to communicate with the slave 2 by use of the selected channel.
[O 1321
In contrast, for example, the maintenance terminal 4 is used by the worker (meter
reader) of the electric power company who visits for meter-reading. In this time, the
30 maintenance terminal 4 communicates with the slave 2 to obtain the meter-reading
data including an integral value of energy, and the like. Therefore, the channel
setting between the slave 2 and the maintenance terminal 4 is necessary in addition
to the channel setting between the slave 2 and the electric appliance 9.
Lo1331
The channel used by the maintenance terminal 4 is fixed. Hence, if the slave 2 is
prohibited to use the channel allocated to the maintenance terminal 4, the selectable
5 range of channels for the slave 2 is narrowed. In view of an efficiency of use of the
channels, it is not preferable that the number of selectable channels be limited and
nevertheless one channel be exclusively allocated to the maintenance terminal 4 that
is not used frequently.
10 [01341
For this reason, the slave 2 of the present embodiment is configured to use the
channel allocated to the maintenance terminal 4 for communication between the
second I/F 22 and the electric appliance 9 in a time period in which the third I/F 23
does not communicate with the maintenance terminal 4. When acknowledging the
15 start of use of the maintenance terminal 4, the slave 2 that selects the channel to be
used by the maintenance terminal 4 allows the maintenance terminal 4 to use the
channel, selects another channel, and uses the selected channel.
[01351
20 The start of use of the maintenance terminal 4 can be acknowledged by receiving an
electric wave sent from the maintenance terminal 4 when the worker of the electric
power company starts to operate the maintenance terminal 4 in a vicinity of the slave
2. The maintenance terminal 4 is used in the vicinity of the slave 2, and thus the slave
2 can receive an electric wave having a relatively high electrical field intensity. Hence,
25 the slave 2 can acknowledge the start of use of the maintenance terminal 4 by
evaluating the electric field intensity of the electric wave received by the third I/F 23.
The maintenance terminal 4 may send a packet for an entry request to the slave 2 at
the start of use so that the slave 2 receives the address of the maintenance terminal 4
included in the header of this packet.
3 0
[O 1361
As for the slave 2 that selects the channel to be used by the maintenance terminal 4,
when the third I@' 23 acknowledges the start of use of the maintenance terminal 4,
the change instructor 254 instructs the channel selector 252 to select all the channels
sequentially in turn.
@
[01371
5 In the present embodiment, the third interface unit 23 is configured to determine
whether use of the communication terminal (maintenance terminal) 4 is started. The
change instructor 254 is configured to, when the third interface unit 23 determines
that use of the communication terminal 4 is started, provide the change instruction
that indicates, as the second communication channel, a channel that does not cause
10 interference with a channel used by the communication terminal 4. The channel
selector 252 is configured to, when receiving the change instruction from the change
instructor 254, change the second communication channel to the channel indicated by
the change instructor 254.
15 101381
Additionally, the interference evaluator 253 monitors the received signal strength
indications of the individual channels in a period in which the change instructor 254
selects the channels sequentially in turn. The slave 2 detects the channel giving the
received signal strength indication equal to or less than the threshold (reference
20 value) as the available channel, and assigns the available channel as the channel used
by the second I/F 22.
[O 1391
For example, it is assumed that the maintenance terminal 4 uses the channel "0". In
25 this example, as shown in FIG. 7, when the identification information of the slave 2 of
the room 201 is "lo", the least significant digit of this identification information is "0".
When the channel is selected in accordance with the aforementioned rule, the channel
used by the second I/F 22 of the slave 2 is also the channel designated by "0". As a
result, the slave 2 of the room 201 uses the channel same as the channel used by the
30 maintenance terminal 4, for communication with the electric appliance 9.
[O 1401
In the allocation instance shown in FIG. 4, the channel "1" is not used by any slave 2,
and it is assumed that the received signal strength indications of the channels used in
the rooms 103,203, and 303 at the slave 2 of the room 201 are too low to cause
@ interference. When the channels are allocated to the individual slaves 2 as shown in
FIG. 7, the available channels detected by the slave 2 of the room 201 are the four
5 channels "I", "6", "S", and "9".
[01411
When the third I/F 23 of the slave 2 of the room 201 acknowledges the start of use of
the maintenance terminal 4, the change instructor 254 of this slave 2 assigns a right
10 of using the channel " 0 currently assigned to the second I F 22 to the maintenance
terminal 4, and searches the available channels for the channel for communication
with the electric appliance 9.
[01421
15 The available channels of the slave 2 are the four channels "I", "6", "S", and "9". In the
case of using the rule that the channel with the smallest number of the numbers of
the available channels is selected, the slave 2 selects the channel "1" as the channel
(second communication channel) for communication with the electric appliance 9 as
shown in FIG. 8. The rule for the slave 2 to select the channel may be appropriately
20 determined, and for example the slave 2 can select another available channel.
LO1431
The slave 2 changes the channel for communication with the electric appliance 9, and
hence the slave 2 sends a preliminary notice to the electric appliance 9 before
25 changing the channel, to instruct the electric appliance 9 to also change the channel.
Note that, the association between the electric appliance 9 and the slave 2 is
necessary. For this reason, the information for identifying the energy meter 1 is
included in the packet sent from the slave 2 to the electric appliance 9 to give an
instruction of change of the channel, and thus the electric appliance 9 can confirm
30 that the slave 2 is a communication partner.
[O 1441
The slave 2 selects the pre-change channel as the channel to be used, after a lapse of a
prescribed time period from the end of communication with the maintenance terminal
4. Further, before selecting the pre-change channel, the slave 2 provides a preliminary
notice regarding the change of the channel to the electric appliance 9. As described
above, the slave 2 that normally uses the same channel as the maintenance terminal
5 4 changes temporarily the normally used channel to communicate with the
maintenance terminal 4. The process allows the slave 2 to normally use the channel
same as the channel used by the maintenance terminal 4, and thus the efficiency of
use of channels of the slave 2 can be improved.
10 [01451
Moreover, it is desirable that the slave 2 instruct the electric appliance 9 in the
facility associated with the slave 2 and the maintenance terminal 4 carried by the
person who installs the slave 2, to perform test communication similar to the test
communication performed by the slave 2. While the electric appliance 9 and the
15 maintenance terminal 4 perform the test communication, the communication quality
evaluator 255 of the slave 2 giving the instruction of the test communication monitors
the received signal strength indications relating to the electric appliance 9 and the
maintenance terminal 4, and obtains the communication qualities from the electric
appliance 9 and the maintenance terminal 4. For example, the communication quality
20 is communication statistic information such as a communication error rate and a
retransmission rate.
[O 1461
The communication quality evaluator 255 of the slave 2 makes evaluation by
25 comparing at least one of the received signal strength indication and the
communication quality with a threshold, and accordingly instructs the electric
appliance 9 and the maintenance terminal 4 to reduce the output power to the
allowable lower limit. In this manner, when the slave 2 sets the channel, the output
power (transmission power) of each of the electric appliance 9 and the maintenance
30 terminal 4 is reduced to an allowable lower limit. Therefore, the possibility that the
electric appliance 9 in one facility and the maintenance terminal 4 are associated with
the slave 2 of another facility is reduced. Consequently, it is possible to avoid
occurrence of interference of the electric appliance 9 of one facility and the
maintenance terminal 4 with the slave 2 of another facility.
e I01471
As described above, the slave 2 of the energy management system 10 of the present
5 embodiment is a slave of an energy management system, which is attached to the
energy meter 1 for measuring the energy consumed in the facility 100 and has a
function of transmitting to the upper device 30 the meter-reading data including an
amount of the energy measured by the energy meter 1. The slave 2 includes the first
interface unit 21, the second interface unit 22, and the third interface unit 23. The
10 first interface unit 21 is configured to communicate with the upper device 30 through
the first communication path 11. The second interface unit 22 is configured to perform
wireless communication with the electric appliance 9, which is one of electric
appliances used in the facility 100 and has the communication function, through the
second communication path 12 using the electric waves as the transmission medium.
15 The third interface unit 23 is configured to perform wireless communication with the
maintenance terminal 4 having at least a function of obtaining the meter-reading
data through the third communication path 13 using the electric wave as the
transmission medium. The second interface unit 22 and the third interface unit 23
perform wireless communication by use of the same protocol.
2 0
[O 1481
Further, in the slave 2 of the energy management system 10 of the present
embodiment, the first interface unit 21 is configured to perform the power line
communication with the upper device 30 through the first communication path 11
25 using the distribution line 5 on the upstream side of the energy meter 1 as the
transmission medium.
[O 1491
Further in the slave 2 of the energy management system 10 of the present
30 embodiment, the first communication path 11 is the distribution line (second path)
502 connected to the secondary side of the transformer 6 for sending commercial
power to the facility 100.
[O 1501
Moreover, with regard to the slave 2 of the energy management system 10 of the
@ present embodiment, the upper device 30 includes the upper server 8 and the master
3. The upper server 8 is a server computer configured to collect the meter-reading
5 data from the energy meters 1 of the plurality of facilities 100 in a management area.
The master 3 has the communication function with the upper server 8 and is
configured to send to the upper server 8 the meter-reading data obtained from at least
one of the energy meters 1 of the facilities 100.
10 [01511
Furthermore, with regard to the slave 2 of the energy management system 10 of the
present embodiment, the maintenance terminal 4 has the communication function
with the electric appliance 9.
15 lo1521
Additionally, the slave 2 of the energy management system 10 of the present
embodiment further includes the channel selector 252, the interference evaluator 253,
and the change instructor 254. The channel selector 252 is configured to select the
communication channels used by the second interface unit 22 and the third interface
20 unit 23 from channels in the predetermined selectable range. The interference
evaluator 253 is configured to evaluate the degree of interference through comparison
of the prescribed threshold with the evaluation value indicative of the degree of
interference in a case where the channel selected by the channel selector 252 is used.
The change instructor 254 is configured to instruct the channel selector 252 to change
25 the channel when the evaluation value is in a range, defined by the threshold, in
which the degree of interference is relatively high.
LO1531
Moreover, the slave 2 of the energy management system 10 of the present
30 embodiment further includes the identification information holding unit 251. The
identification information holding unit 251 is configured to hold the identification
information that is unique within the management area of the upper device 30. The
channel selector 252 is configured to specify the channel based on the identification
P642084
information held in the identification information holding unit 251 by use of the
predetermined rule, and select the specified channel as the initial channel. The
@ identification information holding unit 251 is configured to select the channel
different from the initial channel as the communication channel when receiving the
5 change instruction from the change instructor 254, and to select the channel same as
the initial channel as the communication channel when not receiving the change
instruction from the change instructor 254.
10 1541
10 Additionally, in the slave 2 of the energy management system 10 of the present
embodiment, the interference evaluator 253 has a function of detecting an available
channel which is less likely to cause interference from the channels in the selectable
range, and thereafter of providing the information of the detected available channel to
the change instructor 254. The change instructor 254 is configured to instruct the
15 channel selector 252 to change the current channel to one selected from the available
channels indicated by the information provided from the interference evaluator 253.
10 1551
Further, in the slave 2 of the energy management system 10 of the present
20 embodiment, the change instructor 254 is configured to instruct the channel selector
252 to change the channel used by the second interface unit 22 from the current
channel to an available channel that is less likely to cause interference when the third
interface unit 23 acknowledges the start of use of the maintenance terminal 4 in a
case where the channel used by the second interface unit 22 is same as the channel
25 used by the maintenance terminal 4.
101561
Moreover, the slave 2 of the energy management system 10 of the present
embodiment further includes the communication quality evaluator 255 and the power
30 instructor 256. The communication quality evaluator 255 is configured to perform test
communication by use of the channel selected by the channel selector 252 to evaluate
the communication quality between the slave 2 and the electric appliance 9 through
the communication path 12. The power instructor 256 is configured to decrease the
output power of the second interface unit 22 down to the allowable lower limit within
the range in which the communication quality is kept fine.
5 Furthermore, in the slave 2 of the energy management system 10 of the present
embodiment, the channel selector 252 may select a frequency used for communication.
Alternatively, the channel selector 252 may select a time slot used for communication.
Alternatively, the channel selector 252 may select a combination of a frequency and a
time slot used for communication.
10
[O 1581
Additionally, with regard to the slave 2 of the energy management system 10 of the
present embodiment, the identification information held in the identification
information holding unit 251 is given by the upper device 30.
15
[O 1591
In other words, the slave 2 of the energy management system 10 of the present
embodiment includes the following first to twelfth features. Note that, the second to
twelfth features are optional.
20
[0160]
In the first feature, the slave 2 is a slave suitable for energy management systems for
collecting, from the energy meter 1 for measuring an amount of electric energy
supplied from the power source (commercial AC power source) 14 to the
25 predetermined place (facility 100) through the distribution line 5, the meter-reading
data containing the amount of electric energy. The slave 2 includes the first interface
unit 21, the second interface unit 22, the third interface unit 23, and the controller 25.
The first interface unit 21 is configured to communicate with the upper device 30. The
second interface unit 22 is configured to communicate with the electric appliance 9
30 installed in the predetermined place (facility 100). The third interface unit 23 is
configured to communicate with the communication terminal 4. The controller 25 has:
the function of obtaining the meter-reading data from the energy meter 1; the
function of controlling the first interface unit 21 to send the meter-reading data to the
P642084
upper device 30; and the function of controlling the third interface unit 23 to send the
meter-reading data to the communication terminal 4. The second interface unit 22
@, and the third interface unit 23 each are configured to perform wireless communication
using an electric wave. The second interface unit 22 and the third interface unit 23
5 are configured to use the same protocol.
[01611
In the second feature based on the first feature, the protocol used by the second
interface unit 22 and the third interface unit 23 is a protocol defining a plurality of
10 channels different from each other. The second interface unit 22 and the third
interface unit 23 are configured to perform wireless communication by use of different
communication channels. The different communication channels are selected from the
plurality of channels so that interference between an electric wave from the second
interface unit 22 and an electric wave from the third interface unit 23 does not occur.
15
[O 1621
In the third feature based on the first or second feature, the first interface unit 21 is
connected to the upper device 30 through the distribution line 5. The first interface
unit 21 is configured to perform power line communication with the upper device 30
20 through the distribution line 5.
[01631
In the fourth feature based on the third feature, the energy meter 1 is connected to
the power source 14 through the transformer (step-down transformer) 6 configured to
25 adjust electricity from the power source 14 to electricity appropriate to the
predetermined place. The distribution line 5 includes the first path 501 between the
power source 14 and the transformer 6, and the second path 502 between the
transformer 6 and the energy meter 1. The upper device 30 is connected to the second
path 502. The first interface unit 21 is configured to perform the power line
30 communication with the upper device 30 through the second path 502.
[01641
In the fifth feature based on any one of the first to fourth features, the controller 25
includes the channel selector 252, the interference evaluator 253, and the change
instructor 254. The channel selector 252 is configured to select a communication
@
channel to be used for at least one of the wireless communication by the second
interface unit 22 and the wireless communication by the third interface unit 23, from
5 a plurality of channels. The interference evaluator 253 is configured to determine
whether interference of electric waves occurs in the communication channel. The
change instructor 254 is configured to provide the change instruction to the channel
selector 252 when the interference evaluator 253 determines that the interference
occurs. The channel selector 252 is configured to change the communication channel
10 in response to reception of the change instruction from the change instructor 254.
[01651
In the sixth feature based on the fifth feature, the controller 25 includes the
identification information holding unit 251 storing the identification information
15 unique to the slave 2. The channel selector 252 is configured to select from the
plurality of channels the initial channel as the candidate for the communication
channel, depending on the identification information stored in the identification
information holding unit 251. The channel selector 252 is configured to, when
receiving the change instruction from the change instructor 254, select from the
20 plurality of channels a channel different from the initial channel, and set the selected
channel as the communication channel. The channel selector 252 is configured to,
when not receiving the change instruction from the change instructor 254, set the
initial channel as the communication channel.
25 [0166]
In the seventh feature based on the fifth or sixth feature, the interference evaluator
253 is configured to determine whether the plurality of channels includes at least one
available channel that does not cause interference of the electric waves. The
interference evaluator 253 is configured to, when determining that the plurality of
30 channels includes the at least one available channel, provide available channel
information identifying the at least one available channel to the change instructor 254.
The change instructor 254 is configured to select a designated available channel to be
set as the communication channel from the at least one available channel identified
by the available channel information, and provide the change instruction indicating
the designated available channel to the channel selector 252. The channel selector 252
@ is configured to, when receiving the change instruction from the change instructor 254,
set the designated available channel indicated by the change instruction as the
5 communication channel.
[01671
In the eighth feature based on any one of the fifth to seventh features, the controller
25 further includes the communication quality evaluator 255 and the power instructor
10 256. The communication quality evaluator 255 is configured to evaluate a
communication quality of the communication channel selected by the channel selector
252. The power instructor 256 is configured to set the intensity of the electric wave
allocated to the communication channel to the lower limit of the range of intensities
allowing the communication quality evaluated by the communication quality
15 evaluator 255 to satisfy the predetermined condition.
[01681
In the ninth feature based on any one of the fifth to eighth features, the
communication channel is a channel to be used for the wireless-communication by the
20 third interface unit 23. The channel selector 252 is configured to designate the second
communication channel to be used for the second wireless communication. The third
interface unit 23 is configured to determine whether use of the communication
terminal 4 is started. The change instructor 254 is configured to, when the third
interface unit 23 determines that use of the communication terminal 4 is started,
25 provide, to the channel selector 252, the change instruction that indicates, as the
second communication channel, a channel that does not cause interference with a
channel used by the communication terminal 4. The channel selector 252 is configured
to, when receiving the change instruction from the change instructor 254, change the
second communication channel to the channel indicated by the change instructor 254.
30
[01691
In the tenth feature based on any one of the fifth to ninth features, each of the
plurality of channels is defined by a frequency, a time slot, or a combination of a
frequency and a time slot.
@ [01701
In the eleventh feature based on the sixth feature, the identification information is
5 given by the upper device 30 to the slave 2.
[01711
In the twelfth feature based on any one of the first to eleventh features, the slave 2 is
attached to the energy meter 1.
10
[O 1721
According to the slave 2 of the energy management system 10 of the present
embodiment as described above, the second interface unit 22 and the third interface
unit 23 use the same protocol. Therefore, there is an advantageous effect that i t is
15 possible to allow the slave 2 to communicate with not only the upper device 30 but
also the electric appliance 9 used in the facility 100 and yet to reduce increases in
scale and cost of the slave 2 as possible.
LO1731
20 Further, the energy management system 10 of the present embodiment includes the
master 3, the slave 2, and the maintenance terminal 4. The master 3 has the function
of communicating with the upper server 8 configured to collect the meter-reading data
including the amount of energy consumed in the facility 100 measured by the energy
meter 1 from the energy meters 1 of the plurality of facilities 100 in the management
25 area, and of transmitting the meter-reading data obtained from the energy meter 1 of
the at least one facility 100 to the upper server 8. The slave 2 is attached to the
energy meter 1, and has the function of transmitting the meter-reading data to the
master 3. The maintenance terminal 4 has at least the function of obtaining the
meter-reading data from the slave 2. The slave 2 includes the first interface unit 21,
30 the second interface unit 22, and the third interface unit 23. The first interface unit
21 is configured to communicate with the master 3 through the first communication
path 11. The second interface unit 22 is configured to perform wireless communication
with the electric appliance 9, which is one of electric appliances used in the facility
100 and has the communication function, through the second communication path 12
using the electric waves as the transmission medium. The third interface unit 23 is
@ configured to perform wireless communication with the maintenance terminal 4
having at least the function of obtaining the meter-reading data through the third
5 communication path 13 using the electric wave as the transmission medium. The
second interface unit 22 and the third interface unit 23 perform wireless
communication by use of the same protocol.
[01741
10 In other words, the energy management system 10 of the present embodiment
includes the following thirteenth to fifteenth features. Note that, the fourteenth and
fifteenth features are optional.
[O 1751
15 In the thirteenth feature, the energy management system 10 includes the slave 2, the
upper device 30, and the communication terminal 4. The slave 2 is configured to
obtain, from the energy meter 1 for measuring the amount of electric energy supplied
from the power source 14 to the predetermined place through the distribution line 5,
the meter-reading data containing the amount of electric energy. The upper device 30
20 is configured to obtain the meter-reading data from the slave 2. The communication
terminal 4 is configured to obtain the meter-reading data from the slave 2. The slave 2
includes the first interface unit 21, the second interface unit 22, the third interface
unit 23, and the controller 25. The first interface unit 21 is configured to communicate
with the upper device 30. The second interface unit 22 is configured to communicate
25 with the electric appliance 9 installed in the predetermined place (facility 100). The
third interface unit 23 is configured to communicate with the communication terminal
4. The controller 25 has: the function of obtaining the meter-reading data from the
energy meter 1; the function of controlling the first interface unit 21 to send the
meter-reading data to the upper device 30; and the function of controlling the third
30 interface unit 23 to send the meter-reading data to the communication terminal 4.
The second interface unit 22 and the third interface unit 23 each are configured to
perform wireless communication using an electric wave. The second interface unit 22
and the third interface unit 23 are configured to use the same protocol.
to1761
@
In the fourteenth feature based on the thirteenth feature, the upper device 30
includes the master 3 connected to the distribution line 5 and the upper server 8
5 connected to the master 3. The master 3 has the function of obtaining the
meter-reading data from the slave 2, and the function of sending the meter-reading
data obtained from the slave 2 to the upper server 8. The upper server 8 is configured
to store the meter-reading data received from the master 3.
10 Lo1771
In the fifteenth feature based on the thirteenth or fourteenth feature, the
communication terminal 4 has the function of communicating with the electric
appliance 9.
15 C01781
According to the energy management system 10 of the present embodiment as
described above, the second interface unit 22 and the third interface unit 23 use the
same protocol. Therefore, there is an advantageous effect that i t is possible to allow
the slave 2 to communicate with not only the upper device 30 but also the electric
20 appliance 9 used in the facility 100 and yet to reduce increases in size and cost of the
slave 2 as possible.
[O 1791
(SECOND EMBODIMENT)
25 The energy management system 10 of the present embodiment is different from the
energy management system 10 of the first embodiment in that the first interface unit
21 of the slave 2 is configured to communicate with the master 3 in a wireless
communication manner through the first communication path 11 using the electric
wave as the transmission medium. Hereinafter, the same components as those of the
30 first embodiment are designated by the same reference signs and explanations thereof
are deemed unnecessary.
P642084
In brief, in the present embodiment, the first interface unit 21, the second interface
unit 22, and the third interface unit 23 each are configured to perform wireless
I) communication using an electric wave. Therefore, in the present embodiment, as
shown in FIG. 9, the communication between the slave 2 and the master 3, the
5 communication between the slave 2 and the maintenance terminal 4, and the
communication between the slave 2 and the electric appliance 9 are wireless
communication, and hence the slave 2 does not need to be connected to the
distribution line 5.
lo [oi8il
For example, the communication between the first interface unit 21 and the master 3
may be implemented by use of Wi-Fi (registered trademark), a PHs (Personal
Handyphone System) line, or the like.
15 [01821
According to the energy management system 10 of the present embodiment as
described above, the worker does not need to connect the slave 2 to the distribution
line 5 in a process of attaching the slave 2 to the energy meter 1. Consequently, there
is an advantage that the action of installing the slave 2 can be facilitated.
20
[O 1831
Additionally, the first interface unit 21 may be configured to perform wireless
communication by use of the same protocol as the second interface unit 22. In other
words, in the slave 2, the first interface unit 21 and the second interface unit 22 may
25 be configured to use the same protocol.
[01841
According to this configuration, the first interface unit 21, the second interface unit 22,
and the third interface unit 23 of the slave 2 can be implemented by a single
30 communication module, and thus the slave 2 can be downsized and be manufactured
at a lowered cost.
Alternatively, the first interface unit 21 may be configured to perform wireless
communication by use of a difference protocol from the second interface unit 22. In
@, other words, the first interface unit 21 and the second interface unit 22 may be
configured to use different protocols to perform wireless communication so that the
5 first communication path 11 and the second communication path 12 form independent
communication paths. For example, the protocol is a wireless communication scheme,
and defines rules such as frequencies, modulation schemes, time slots, transmission
power of electric waves, receiving sensitivity for electric waves, and alignment of
antennas.
10
[o 1861
In this configuration, the communication path independent from the communication
paths for the communication between the slave 2 and the electric appliance 9 and the
communication between the slave 2 and the maintenance terminal 4 can be used for
15 the communication between the slave 2 and the master 3. Accordingly, this energy
management system 10 can avoid interference between the communication between
the slave 2 and the master 3 and the communication between the slave 2 and the
maintenance terminal 4 or the communication between the slave 2 and the electric
appliance 9.
20
[01871
In the slave 2 of the energy management system 10 of the present embodiment
described above, the first interface unit 21 is configured to communicate with the
upper device 30 in a wireless communication manner through the first communication
25 path 11 using the electric wave as the transmission medium.
[Ol88l
In other words, the slave 2 of the present embodiment includes the following sixteenth
feature in addition to the above first feature. In the sixteenth feature, the first
30 interface unit 21 is configured to perform wireless communication using an electric
wave with the upper device 30.
Additionally, in the slave 2 of the energy management system 10 of the present
embodiment, the first interface unit 21 and the second interface unit 22 are
@ configured to perform wireless communication by use of the same protocol.
5 [01901
In other words, the slave 2 of the present embodiment may include the following
seventeenth feature in addition to the sixteenth feature. In the seventeenth feature,
the first interface unit 21 and the second interface unit 22 are configured to use the
same protocol.
10
[01911
Alternatively, in the slave 2 of the energy management system 10 of the present
embodiment, the first interface unit 21 and the second interface unit 22 may be
configured to use different protocols to perform wireless communication so that the
15 first communication path 11 and the second communication path 12 form independent
communication paths.
[01921
In other words, the slave 2 of the present embodiment may include the following
20 eighteenth feature instead of the seventeenth feature. In the eighteenth feature, the
first interface unit 21 and the second interface unit 22 are configured to use different
protocols.
[01931
25 Note that, the slave 2 of the present embodiment may include at least one of the above
second, fifth to twelfth features, if necessary.
[O 1941
Additionally, the slave 2 of the present embodiment may include at least one of the
30 following nineteenth to twenty-third features, if necessary.
[O 1951
In the nineteenth feature based on any one of the sixteenth to eighteenth features, the
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controller 25 includes the channel selector 252, the interference evaluator 253, and
the change instructor 254. The channel selector 252 is configured to select a
communication channel (third communication channel) to be used for the wireless
communication by the first interface unit 21, from a plurality of channels. The
5 interference evaluator 253 is configured to determine whether interference of electric
waves occurs in the communication channel (third communication channel). The
change instructor 254 is configured to provide the change instruction to the channel
selector 252 when the interference evaluator 253 determines that the interference
occurs. The channel selector 252 is configured to change the communication channel
10 (third communication channel) in response to reception of the change instruction from
the change instructor 254.
[0196l
In the twelfth feature based on the nineteenth feature, the controller 25 includes the
15 identification information holding unit 251 storing the identification information
unique to the slave 2. The channel selector 252 is configured to select from the
plurality of channels the initial channel as the candidate for the communication
channel (third communication channel), depending on the identification information
stored in the identification information holding unit 251. The channel selector 252 is
20 configured to, when receiving the change instruction from the change instructor 254,
select from the plurality of channels a channel different from the initial channel, and
set the selected channel as the communication channel (third communication channel).
The channel selector 252 is configured to, when not receiving the change instruction
from the change instructor 254, set the initial channel as the communication channel
25 (third communication channel).
[01971
In the twenty-first feature based on the twenty-second or twenty-third feature, the
interference evaluator 253 is configured to determine whether the plurality of
30 channels includes at least one available channel that does not cause interference of
the electric waves. The interference evaluator 253 is configured to, when determining
that the plurality of channels includes the available channel, provide available
channel information identifying the at least one available channel to the change
instructor 254. The change instructor 254 is configured to select a designated
available channel to be set as the communication channel from the at least one
@ available channel identified by the available channel information, and provide the
change instruction indicating the designated available channel to the channel selector
5 252. The channel selector 252 is configured to, when receiving the change instruction
from the change instructor 254, set the designated available channel indicated by the
change instruction as the communication channel (third communication channel).
[0198]
10 In the twenty-second feature based on any one of the nineteenth to twenty-first
features, the controller 25 further includes the communication quality evaluator 255
and the power instructor 256. The communication quality evaluator 255 is configured
to evaluate a communication quality of the communication channel (third
communication channel) selected by the channel selector 252. The power instructor
15 256 is configured to set the intensity of the electric wave allocated to the
communication channel (third communication channel) to the lower limit of the range
of intensities allowing the communication quality evaluated by the communication
quality evaluator 255 to satisfy the predetermined condition.
In the twenty-third feature based on any one of the nineteenth to twenty-second
features, the third interface unit 23 is configured to determine whether use of the
communication terminal 4 is started. The change instructor 254 is configured to,
when the third interface unit 23 determines that use of the communication terminal 4
25 is started, provide, to the channel selector 252, the change instruction that indicates,
as the third communication channel, a channel that does not cause interference with a
channel used by the communication terminal 4. The channel selector 252 is configured
to, when receiving the change instruction from the change instructor 254, change the
third communication channel to the channel indicated by the change instructor 254.
3 0
[02001
The other configurations and functions are same as those of the first embodiment.

CLAIMS
@ 1. A slave suitable for energy management systems for collecting, from an energy
meter for measuring an amount of electric energy supplied from a power source to a
5 predetermined place through a distribution line, meter-reading data containing the
amount of electric energy,
the slave comprising:
a first interface unit configured to communicate with an upper device;
a second interface unit configured to communicate with an electric appliance
10 installed in the predetermined place;
a third interface unit configured to communicate with a communication
terminal; and
a controller having: a function of obtaining the meter-reading data from the
energy meter; a function of controlling the first interface unit to send the
15 meter-reading data to the upper device; and a function of controlling the third
interface unit to send the meter-reading data to the communication terminal,
the second interface unit and the third interface unit each being configured to
perform wireless communication using an electric wave, and
the second interface unit and the third interface unit being configured to use
20 the same protocol.
2. The slave suitable for energy management systems, according to claim 1, wherein:
the protocol used by the second interface unit and the third interface unit is a
protocol defining a plurality of channels different from each other;
2 5 the second interface unit and the third interface unit are configured to perform
wireless communication by use of different communication channels;
the different communication channels are selected from the plurality of
channels so that interference between an electric wave from the second interface unit
and an electric wave from the third interface unit does not occur.
3 0
3. The slave suitable for energy management systems, according to claim 1, wherein:
the first interface unit is connected to the upper device through the
distribution line; and
- 59 -
the first interface unit is configured to perform power line communication with
the upper device through the distribution line.
@
4. The slave suitable for energy management systems, according to claim 3, wherein:
5 the energy-meter is connected to the powe-source through a transformer
configured to adjust electricity from the power-source to electricity appropriate to the
predetermined-place;
the distribution line includes a first-path between the power-source and the
transformer, and a second-path between the transformer and the energy-meter;
10 the upper device is connected to the second-path; and
the first interface unit is configured to perform power line communication with
the upper device through the second-path.
5. The slave suitable for energy management systems, according to claim 1, wherein
15 the first interface unit is configured to perform wireless communication using
an electric wave with the upper device.
6. The slave suitable for energy management systems, according to claim 5, wherein
the first interface unit and the second interface unit are configured to use the
20 same protocol.
7. The slave suitable for energy management systems, according to claim 5, wherein
the first interface unit and the second interface unit are configured to use
different protocols.
2 5
8. The slave suitable for energy management systems, according to claim 1, wherein:
the controller includes
a channel selector configured to select a communication channel to be
used for at least one of the wireless communication by the second interface unit and
30 the wireless communication by the third interface unit, from a plurality of channels,
an interference evaluator configured to determine whether interference
of electric waves occurs in the communication channel, and
a change instructor configured to provide a change instruction to the
channel selector when the interference evaluator determines that the interference
occurs; and
115 the channel selector is configured to change the communication channel in
response to reception of the change instruction from the change instructor.
5
9. The slave suitable for energy management systems, according to claim 8, wherein:
the controller includes an identification information holding unit storing
identification information unique to the slave;
the channel selector is configured to select from the plurality of channels an
10 initial channel as a candidate for the communication channel, depending on the
identification information stored in the identification information holding unit;
the channel selector is configured to, when receiving the change instruction
from the change instructor, select from the plurality of channels a channel different
from the initial channel, and set the selected channel as the communication channel;
15 and
the channel selector is configured to, when not receiving the change
instruction from the change instructor, set the initial channel as the communication
channel.
20 10. The slave suitable for energy management systems, according to claim 8, wherein:
the interference evaluator is configured to determine whether the plurality of
channels includes at least one available channel that does not cause interference of
electric waves;
the interference evaluator is configured to, when determining that the
25 plurality of channels includes the at least one available channel, provide available
channel information identifying the at least one available channel to the change
instructor;
the change instructor is configured to select a designated available channel to
be set as the communication channel from the at least one available channel
30 identified by the available channel information, and provide the change instruction
indicating the designated available channel to the channel selector; and
the channel selector is configured to, when receiving the change instruction
from the change instructor, set the designated available channel indicated by the
change instruction as the communication channel.
11. The slave suitable for energy management systems, according to claim 8, wherein
the controller further includes
5 a communication quality evaluator configured to evaluate a
communication quality of the communication channel selected by the channel selector,
and
a power instructor configured to set an intensity of an electric wave
allocated to the communication channel to a lower limit of a range of intensities
10 allowing the communication quality evaluated by the communication quality
evaluator to satisfy a predetermined condition.
12. The slave suitable for energy management systems, according to claim 8, wherein:
the communication-channel is a channel to be used for the
15 wireless-communication by the third interface unit;
the channel selector is configured to select a second communication channel to
be used for the wireless communication by the second interface unit from a plurality
of channels;
the third interface unit is configured to determine whether use of the
20 communication terminal is started;
the change instructor is configured to, when the third interface unit
determines that use of the communication terminal is started, provide to the channel
selector the change instruction that indicates, as the second communication channel,
a channel that does not cause interference with a channel used by the communication
25 terminal; and
the channel selector is configured to, when receiving the change instruction
from the change instructor, change the second communication channel to the channel
indicated by the change instructor.
30 13. The slave suitable for energy management systems according to claim 8, wherein
each of the plurality of channels is defined by a frequency, a time slot, or a
combination of a frequency and a time slot.
14. The slave suitable for energy management systems according to claim 9, wherein
the identification information is given by the upper device to the slave.
0
15. The slave suitable for energy management systems according to claim 1, wherein
5 the slave is attached to the energy meter.
16. An energy management system comprising:
a slave configured to obtain, from an energy meter for measuring an amount of
electric energy supplied from a power source to a predetermined place through a
10 distribution line, meter-reading data containing the amount of electric energy;
an upper device configured to obtain the meter-reading data from the slave;
and
a communication terminal configured to obtain the meter-reading data from
the slave,
15 the slave including:
a first interface unit configured to communicate with the upper device;
a second interface unit configured to communicate with an electric appliance
installed in the predetermined place;
a third interface unit configured to communicate with the communication
20 terminal; and
a controller having: a function of obtaining the meter-reading data from the
energy meter; a function of controlling the first interface unit to send the
meter-reading data to the upper device; and a function of controlling the third
interface unit to send the meter-reading data to the communication terminal,
2 5 the second interface unit and the third interface unit each being configured to
perform wireless communication using an electric wave, and
the second interface unit and the third interface unit being configured to use
the same protocol.
30 17. The energy management system according to claim 16, wherein:
the upper device includes a master connected to the distribution line and an
upper server connected to the master;
the master has a function of obtaining the meter-reading data from the slave,
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and a function of sending the meter-reading data obtained from the slave to the upper
server; and * the upper server is configured to store the meter-reading data received from
the master.
5
18. The energy management system according to claim 16, wherein
the communication terminal has a function of communicating with the electric
appliance.