DESCRIPTION
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
energy management systems.
Background Art
[00021
In the past, there has been proposed an energy management system. In this energy
management system, a slave for communication is attached to an energy meter
installed in a facility, and the slave obtains meter-reading data from the energy meter
and transmits the obtained meter-reading data to an upper device. Thus, the upper
device collects the meter-reading data of the facility.
[00031
For example, according to a configuration disclosed in document 1 (JP 2011-250301 A),
an upper device (master terminal) and a slave (slave terminal) perform power line
communication with each other by use of a distribution line as a communication path,
and thus the upper device obtains meter-reading data from the slave. Further,
document 1 discloses another configuration in which the slave and a maintenance
b
terminal perform wireless communication with each other and thus the maintenance
terminal performs inspection, setting change, and the like of the slave (see
paragraphs [00211 and [00221, and FIG. 1).
[00041
Document 1 discloses a technique of performing the inspection and the setting change
of the slave by use of the maintenance terminal, and further discloses using the
maintenance terminal in order to relay wireless communication. Note that, the
- 1 -
technique disclosed in document 1 is for remote meter-reading, and accordingly the
slave communicates with only the energy meter and the maintenance terminal.
[00051
5 In the past, in consideration of an increase in demand for energy saving and shortage
of power supply, there have been demanded a function of monitoring power
consumption in electric appliances used in facilities to prompt residents to save on
electricity, and a function of controlling electric appliances to reduce power
consumption. However, according to the technique disclosed in document 1, the
10 slave and the maintenance are only used to allow the upper device to use the
meter-reading data of the energy meter, and there is no idea that the slave and the
maintenance terminal are used for energy management of the facility.
[00061
15 To enable communication between the slave and the electric appliance, it is necessary
to form a communication path between the slave and the electric appliance. When
the communication path is formed in a wired manner, additional installation of the
communication path is necessary. When the communication path is formed in a
wireless manner, interference between communication between the slave and the
20 maintenance terminal and communication between the slave and the electric
appliance is likely to occur.
Summary of Invention
[00071
25 In view of the above insufficiency, the present invention has aimed to propose a slave
suitable for energy management systems that allows energy management in addition
to meter-reading by employing a function of communicating with an electric appliance
used in a facility in addition to a function of communicating with an upper device and
a maintenance terminal, and allows facilitation of installation of the slave by
30 employing a configuration of performing wireless communication with the
maintenance terminal and the electric appliance, and can prevent interference
between communication with the maintenance terminal and communication with the
electric appliance, and further propose an energy management system including the
slave.
[0008l
The slave suitable for energy management systems of the first aspect in accordance
5 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,
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.
10 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
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
15 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 are configured to perform
wireless communication using electric waves in wireless communication schemes
different from each other.
[00091
According to the slave suitable for energy management systems of the second aspect
in accordance with the present invention, depending on the first aspect, the wireless
communication schemes are protocols.
[oolol
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, and
30 is configured to perform power line communication with the upper device through the
distribution line.
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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
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.
5 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
perform power line communication with the upper device through the second path.
10 [00121
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
first interface unit is configured to perform wireless communication using an electric
wave with the upper device.
15
[OO1 31
According to the slave suitable for energy management systems of the sixth aspect in
accordance with the present invention, depending on the fifth aspect, the first
interface unit and the third interface unit are configured to perform wireless
20 communication in the same wireless communication scheme.
[00141
According to the slave suitable for energy management systems of the seventh aspect
in accordance with the present invention, depending on the fifth aspect, the first
25 interface unit and the second interface unit are configured to perform wireless
communication in the same wireless communication scheme.
[00151
According to the slave suitable for energy management systems of the eighth aspect in
30 accordance with the present invention, depending on any one of the first to seventh
aspects, the controller further includes a channel selector, an interference evaluator,
and a change instructor. The channel selector is configured to select a
communication channel to be used for the wireless communication of at least one of
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the second interface unit and the third interface unit, from a plurality of channels.
The interference evaluator is configured to judge 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 the interference evaluator
5 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.
[00161
10 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
15 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 fiom 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
20 change instructor, set the initial channel as the communication channel.
[OO 171
According to the slave suitable for energy management systems of the tenth aspect in
accordance with the present invention, according to the eighth or ninth aspect, the
25 interference evaluator is configured to judge whether the plurality of channels
includes at least one available channel that does not cause interference of the electric
wave. The interference evaluator 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.
30 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 identified by
the available channel information, and provide the change instruction indicating the
designated available channel to the channel selector. The channel selector is
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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.
5 [00181
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
10 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.
15
[00191
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 in the wireless
20 communication of the third interface unit. The channel selector is configured to
select a second communication channel to be used in the wireless communication of
the second interface unit, from a plurality of channels. The third interface unit is
configured to judge whether use of the communication terminal is started. The
change instructor is configured to, when the third interface unit determines that use
25 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
30 by the change instructor.
[00201
According to the slave suitable for energy management systems of the thirteenth
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aspect in accordance with the present invention, depending on any one of the eighth
to twelfth aspects, each of the plurality of channel is defined by a frequency, a time
slot, or a combination of a frequency and a time slot.
5 [00211
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.
10 [00221
According to the slave suitable for energy management systems of the fifteenth aspect
in accordance with the present invention, depending on the first to fourteenth aspects,
the slave is attached to the energy meter.
15 Lo0231
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
20 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
25 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 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;
30 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
are configured to perform wireless communication using electric waves in wireless
communication schemes different from each other.
[00241
According to the energy management system of the seventeenth aspect in accordance
with the present invention, depending on the sixteenth aspect, the upper device
5 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.
10
[00251
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.
15
Brief Description of the Drawings
[0026]
FIG. 1 is a configuration diagram illustrating an energy management system of one
embodiment in accordance with the present invention.
20 FIG. 2 is a schematic configuration diagram illustrating a primary part of the above
system.
FIG. 3 is a schematic configuration diagram illustrating a primary part of the above
system.
FIG. 4 is a block diagram illustrating a slave of the above energy management
25 system.
FIG. 5 is a schematic configuration diagram illustrating a usage example of the above
energy management system.
FIG. 6 is a diagram illustrating an example of a setting of initial channels relating to
an example shown in FIG. 5.
30 FIG. 7 is an explanatory diagram illustrating an operation in a channel setting
procedure in the above energy management system.
FIG. 8 is a diagram illustrating an example of a setting of channels relating to the
example shown in FIG. 5.
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FIG. 9 is a diagram illustrating an example of the setting of channels relating to the
example shown in FIG. 5.
Description of Embodiments
5 [00271
FIG. 1 shows the energy management system of the present embodiment configured
to collect, from an energy meter 20 for measuring an amount of electric energy
supplied to a predetermined place (in the present embodiment, a facility 1) from a
power source (in the present embodiment, a commercial AC power source) 70 through
10 a distribution line 60, meter-reading data containing the amount of electric energy.
Note that, the power source 70 is not limited to a commercial AC power source.
Further, the predetermined place is not limited to the facility 1.
lo0281
15 The energy management system of the present embodiment includes a slave
(communication device) 10, an upper device 40, and a communication terminal
(maintenance terminal) 50.
[00291
20 The slave 10 is configured to obtain the meter-reading data including the amount of
electric energy from the energy meter 20. For example, as shown in FIG. 4, the slave
10 includes a first interface unit 11, a second interface unit 12, a third interface unit
13, a meter interface unit (not shown), and a controller 100.
25 [00301
The first interface unit 11 is used for communication with the upper device 40. In
other words, the first interface unit 11 is configured to communicate with the upper
device 40. For example, the first interface unit 11 is implemented by a combination
of hardware and software necessary to communicate with the upper device 40.
3 0
[00311
The second interface unit 12 is used for communication with an electric appliance 31
installed in the predetermined place (facility 1). In other words, the second interface
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unit 12 is configured to communicate with the electric appliance 31. The second
interface unit 12 is configured to perform wireless communication using an electric
wave with the communication terminal 50. For example, the second interface unit
12 is implemented by a combination of hardware and software necessary to
5 communicate with the electric appliance 31.
Lo0321
Note that, the electric appliance 31 is not necessarily fixed to the predetermined place.
The electric appliance 31 may be portable and be placed on the predetermined place.
10 In short, it is sufficient that the electric appliance 31 is available in the
predetermined place.
Lo0331
The third interface unit 13 is used for communication with the communication
15 terminal 50. In other words, the third interface unit 13 is configured to communicate
with the communication terminal 50. The third interface unit 13 is configured to
perform wireless communication using an electric wave with the communication
terminal 50. For example, the third interface unit 13 is implemented by a
combination of hardware and software necessary to communicate with the
20 communication terminal 50.
[00341
The meter interface unit is used for communication with the energy meter 20. In
other words, the meter interface unit is configured to communicate with the energy
25 meter 20. For example, the meter interface unit is configured to perform near field
communication using infrared as transmission medium with the energy meter 20.
For example, the meter interface unit is implemented by a combination of hardware
and software necessary to communicate with the energy meter 20.
30 [0035]
The controller 100 has a function of obtaining the meter-reading data from the energy
meter 20. Especially, the controller 100 communicates with the energy meter 20
through the meter interface unit to obtain the meter-reading data from the energy
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meter 20. Further, the controller 100 has a function of controlling the first interface
unit 11 to send the meter-reading data to the upper device 40, and a function of
controlling the third interface unit 13 to send the meter-reading data to the
communication terminal 50.
5
[0036]
The energy meter 20 is connected to the power source 14 through a transformer
(step-down transformer) 6 configured to adjust electricity from the power source 14 to
electricity appropriate to the predetermined place (facility 1). The distribution line
10 60 includes a distribution line (first path) 61 between the power source 14 and the
transformer TI, and a distribution line (second path) 62 between the transformer T1
and the energy meter 20.
Lo0371
15 The upper device 40 is connected to the second path 62. The upper device 40
includes a master 41 connected to the distribution line 60 (the second path 62) and an
upper server 42 connected to the master 41.
[00381
20 The master 41 has a function of obtaining the meter-reading data from the slave 10,
and a function of sending the meter-reading data obtained from the slave 10 to the
upper server 42.
too391
25 The upper server 42 is configured to store the meter-reading data received from the
master 41.
[00401
The communication terminal 50 has a function of obtaining the meter-reading data
30 from the slave 10, and a function of communicating with the electric appliance 31.
[00411
Hereinafter, the energy management system of the present embodiment is described
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in more detail. As shown in FIG. 1, the energy management system described below
includes the energy meter 20 configured to measure an amount of energy consumed in
the facility 1 and the slave 10 attached to the energy meter 20. Note that, the phrase
"the slave 10 is attached to the energy meter 20" means that the slave 10 and the
5 energy meter 20 are installed as a single device. It is preferable that the slave 10
and the energy meter 20 are accommodated in the same casing, but the slave 10 and
the energy meter 20 may be accommodated in different casings.
Lo0421
10 In the following example, the facility 1 is one of dwelling units in a condominium.
However, the facility 1 is not limited to such a dwelling unit, but may be a residence,
an office, or a factory.
Lo0431
15 The energy meter 20 includes an upstream side connected to the distribution line (the
first path 61 and the second path 62) on a secondary side of the transformer TI, and a
downstream side connected to a distribution line (not shown) to a distribution circuit
board 30 installed in the facility.
20 [00441
The location of the transformer T1 depends on a scale of premises receiving
commercial electricity. As for a detached house, the transformer T1 may be situated
on a pole, on the ground, or in the ground, for example. As for a condominium, the
transformer T1 is situated inside an electrical room. Electric appliances used in the
25 facility 1 are connected to distribution lines on a downstream side of the distribution
circuit board 30.
[00451
The slave 10 is placed close to the energy meter 20. For example, the slave 10
30 performs near field communication using infrared as a transmission medium to obtain
the meter-reading data including the amount of energy measured by the energy meter
20. The slave 10 has: a function of transmitting the meter-reading data obtained
from the energy meter 20 to the upper device 40; a function of communicating with
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the electric appliance 31 that is one of electric appliances used in the facility 1 and
has a communication function; and a function of communicating with the
maintenance terminal (communication terminal) 50 described in detail below.
5 Lo0461
In other words, the slave 10 communicates with a desired device through a
corresponding one of three types of communication paths including a first
communication path L1 to the upper device 40, a second communication path L2 to
the electric appliance 31, and a third communication path L3 to the maintenance
10 terminal 50. The detailed configuration of the slave 10 and the communication paths
L1, L2, and L3 are described below. Communication between the slave 10 and the
upper device 40 through the first communication path L1 is referred to as "A-route
communication", and communication between the slave 10 and the electric appliance
31 through the second communication path L2 is referred to as "B-route
15 communication".
Lo0471
The upper device 40 includes the master 41 and the upper server 42. The master 41
is placed adjacent to the transformer T1 and communicates with the slave 10 through
20 the first communication path L1. The upper server 42 communicates with the
master 41 through a transmission path L4 formed between the upper server 42 and
the master 41.
Lo0481
25 The upper server 42 is a server computer configured to collect the meter-reading data
from the facilities 1 in a management area. The upper server 42 may be operated by
an electric power company and a service agent company that performs collection of
the electric bill and aggregation of the amount of energy of the facility 1 on behalf of
the electric power company.
3 0
Lo0491
The master 41 collects the meter-reading data of each facility 1 from the slave 10
provided to at least one facility 1 through the first communication path L1.
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Additionally, the master 41 transmits the meter-reading data collected from the at
least one slave 10 to the upper server 42 at one time. In short, the master 41
communicates the slave 10 managed by the master 41 through the first
communication path L1 and aggregates the meter-reading data of the at least one
5 facility 1. The master 41 sends the aggregated meter-reading data to the upper
server 42 at one time or divides the aggregated meter-reading data into parts and
transmits the parts sequentially. The slave 10 directly communicates with the
master 41 or communicates with the master 41 by use of multihop communication.
10 [00501
The electric appliance 31 communicating with the slave 10 includes at least one of a
first appliance 311 including a display and a second appliance 312 having a function
of receiving a change request of operation or settings through communication with
another device. There may be a third appliance 313 interposed between the slave 10
15 and any of the first appliance 311 and the second appliance 312. The third appliance
313 is configured to relay communication. In short, the electric appliance 31 may be
any one of the first appliance 311, the second appliance 312, a combination of the first
appliance 311 and the third appliance 313, a combination of the second appliance 312
and the third appliance 313 and a combination of the first appliance 311, the second
20 appliance 312, and the third appliance 313.
[00511
The third appliances 313 may include a relay 32 and a power measurement unit 33.
The relay 32 merely relays communication between the first appliance 311 or the
25 second appliance 312 and the slave 10. The power measurement unit 33 is attached
to the distribution circuit board 30, and has a relaying function in addition to a
function of measurement of power consumptions at a main circuit and a branch
circuit.
30 [00521
The first appliance 311 includes a display 3111 configured to display various types of
information, and a wireless interface unit 3112 configured to perform bidirectional
wireless communication using an electric wave as a transmission medium with other
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devices. For example, the display 3111 displays an amount of energy obtained from
the power measurement unit 33 attached to the distribution circuit board 30 or an
operation condition or setting information of the second appliance 312.
5 Lo0531
Note that, it is preferable that the first appliance 311 include an operation unit for
selecting information displayed by the display 3111 and providing instructions to
other devices. The first appliance 311 may be a dedicated device, a set of an
appropriate interface device and a television receiver, or a mobile device such as a
10 tablet and a smartphone.
[00541
The second appliance 312 includes a functional unit 3121 configured to provide a
function for a desired device, and a wireless interface unit 3122 configured to perform
15 bidirectional wireless communication using an electric wave as a transmission
medium with other devices. The second appliance 312 has a function of notifying
other devices of an operation condition of the second appliance 312 through the
wireless interface unit 3122 in addition to a function of receiving a request of change
of an operation or settings from another device through the wireless interface unit
20 3122.
[00551
The relay 32 includes a wireless interface unit (hereinafter, "interface unit" is
abbreviated as "IIF" if needed) 321 configured to perform bidirectional wireless
25 communication using an electric wave as a transmission medium with the slave 10
and the first appliance 311. In other words, the relay 32 forms a communication
path L21, that is the second communication path L2, between the relay 32 and the
slave 10, and forms a communication path L22 between the relay 32 and the first
appliance 311.
30
Lo0561
The power measurement unit 33 can measure the power consumptions at the main
circuit and the branch circuit, and allow the first appliance 311 to display
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measurement results, and allow the second appliance 312 to operate based on the
measurement results. The power measurement unit 33 may have a function of
transmitting the measurement results to the upper device 40 or the communication
terminal 50 through the slave 10.
5
Lo0571
The relay 32 performs bidirectional communication with the first appliance 311
through the communication path L22 in which a transmission medium is electric
waves. Further, the power measurement unit 33 performs bidirectional wireless
10 communication with at least one of the first appliance 311 and the second appliance
322 through the communication path L22 in which a transmission medium is electric
waves.
Lo0581
15 As described above, each of the relay 32 and the power measurement unit 33 has a
function of communicating with the slave 10. Bidirectional wireless communication
using the communication path L21 in which the transmission medium is electric
waves is used for communication between the slave 10 and the relay 32 as well as the
power measurement unit 33. The relay 32 and the power measurement unit 33
20 include the wireless I/F 321 and a wireless I/F 331 to perform wireless communication
with the slave 10, respectively.
[00591
The first appliance 311 may be configured to communicate with the second appliance
25 312, however such a configuration is not illustrated in FIG. 1. In this configuration,
the first appliance 311 communicates with the slave 10 and the second appliance 312,
and thus functions as a so-called HEMS (Home Energy Management System)
controller.
30 [00601
The slave 10 includes the first I/F 11 for communicating with the upper device 40
through the first communication path L1 and the second I/F 12 for communicating
with the electric appliance 31 through the second communication path L2.
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Additionally, the slave 10 includes the third IIF 13 for communicating with the
maintenance terminal 50 through the third communication path L3, and the
controller 100 configured to overall control the first IIF 11, the second I F 12, and the
third I F 13.
5
[006 11
Each of the first I F 11, the second IIF 12, and the third I F 13 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 L1, the
10 second communication path L2, and the third communication path L3.
[00621
The slave 10 includes as hardware components a device such as a microcomputer
including a processor designed to operate in accordance with programmes and a
15 device functioning as an interface. The programmes define operations of the
microcomputer to implement functions described below.
[00631
As illustrated in FIG. 2 and FIG. 3, in the present embodiment, electric waves are
20 used as the transmission media of the second communication path L2 and the third
communication path L3 for wireless communication.
The first communication path L1 is selected from the communication path L11 (see
25 FIG. 2) in which the transmission medium is the distribution line (second path 62) on
the secondary side of the transformer T1 and the communication path L12 (see FIG.
3) in which the transmission path is electric waves.
Lo0651
30 The first I F 11 is configured in accordance with at least one of a specification suitable
for the communication path L11 for the power line communication and a specification
suitable for the communication path L12 for the wireless communication. In the
present embodiment, the first interface unit 11 has the function of performing the
power line communication with the upper device 40 through the distribution line
(second path) 62 and the function of performing the wireless communication using
electric waves with the upper device 40.
5 [00661
The maintenance terminal 50 is basically used for obtaining the meter-reading data
through the slave 10. However, the maintenance terminal 50 has a function of
communicating with appliances used in the facility 1. For example, the maintenance
terminal 50 may change the settings of the electric appliance 31 or control the
10 operation of the electric appliance 31 through the slave 10, by sending instructions for
the electric appliance 31 to the slave 10.
[00671
Additionally, parameters set to the slave 10 may be changed by use of the
15 maintenance terminal 50, and instructions for termination of power supply to homes
can be given by use of the maintenance terminal 50. The parameters of the slave 10
may include a time interval of obtaining the meter-reading data, transmission power
and receiving sensitivity for wireless communication, a modulation scheme, and a
frequency, for example.
20
[OO~BI
For example, wireless communication can be performed according to a specification of
specified low power radio stations with 920 MHz band and transmission power equal
to or less than 20 mW, but other schemes such as Wi-Fi (registered trademark),
25 ZigBee (registered trademark), and Bluetooth (registered trademark) can be used.
[0069]
The present embodiment is characterized in that wireless communication schemes
(e.g., frequencies, modulation schemes, and time slots) used for the second
30 communication path L2 and the third communication path L3 are different from each
other. A channel allocated to the communication path is defined by a frequency for
transmitting information. A time slot is a time period obtained by dividing a
communication period, and such a time slot also can be used as the channel for
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communication. In summary, the channel may be defined by a frequency, a time slot,
or a combination of a frequency and a time slot.
[00701
5 When different channels are allocated to individual communication paths,
information can be transmitted without causing interference between the different
communication paths.
Lo07 11
10 Although the transmission media of the second communication path L2 and the third
communication path L3 are electric waves, different schemes (wireless communication
schemes) are used for the second communication path L2 and the third
communication path L3 to form communication paths independent from each other.
The phrase "communication paths independent from each other" means
15 communication paths in which interference between electric waves of the second
interface unit 12 and the third interface unit 13 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.
20 [130721
Consequently, information transmitted through the second communication path L2
does not interfere with information transmitted through the third communication
path L3. In other words, the communication between the slave 10 and the
maintenance terminal 50 does not interfere with the communication between the
25 slave 10 and the electric appliance 31.
[I30731
Further the communication through the second communication path L2 and the
communication through the third communication path L3 do not interfere, and
30 therefore it is easy to keep desired communication speeds. Note that, in a case where
different modulation schemes are used for the different communication paths,
interference may occur when the same channel is used for the communication paths.
However, when the modulation schemes are different, there may be differences
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between transmission speeds and communication qualities, and thus a possibility of
avoiding interference is high.
[00741
5 Note that, when the transmission medium of the first communication path L1 is
electric waves, in some cases the first communication path L1 is allowed to share the
same path with the second communication path L2 or the third communication path
L3. In other words, the first interface unit 11 may be configured to perform wireless
communication in a scheme same as the scheme of the second interface unit 12, or
10 may be configured to perform wireless communication in a scheme same as the
scheme of the third interface unit 13.
[00751
In the former case, the first interface unit 11 and the second interface unit 12 perform
15 the wireless communication in the same scheme. In other words, the first
communication path L1 and the second communication path L2 share the same
communication path, and therefore the first I/F 11 and the second I/F 12 can be
implemented by the same unit. In the latter case, the first interface unit 11 and the
third interface unit 13 perform the wireless communication in the same scheme. The
20 third communication path L3 and the second communication path L2 are independent
communication paths, but the third communication path L3 and the first
communication path L1 share the same communication path. Hence the third I/F 13
and the first I/F 11 can be implemented by the same unit. Consequently, in any case,
the structure of the slave 10 can be simplified.
2 5
[0076l
Note that, when a plurality of communication paths for wireless communication are
made independent from each other, it is preferable that to improve independence of
the communication paths a type, a direction, polarization of an antenna can be
30 changed in addition to frequencies, modulation schemes, time slots, transmission
power, and receiving sensitivity, for each communication path. In short, the wireless
communication scheme is a protocol defining rules such as frequencies, modulation
schemes, time slots, transmission power of electric waves, receiving sensitivity for
electric waves, and alignment of antennas.
[00771
In other words, the second interface unit 12 is configured to perform the wireless
5 communication in a protocol different from a protocol used by the third interface unit
13. For example, the protocol of the second interface unit 12 is determined to define
channels that do not cause interference between electric waves of the second interface
unit 12 and the third interface unit 13 for any channel defined by the protocol of the
third interface unit 13.
10
[00781
In the aforementioned configuration, the maintenance terminal 50 is added, and thus
use of the maintenance terminal 50 allows collection of the meter-reading data of each
facility 1 even when the communication between the slave 10 and the upper device 40
15 fails.
[00791
In a case where the distribution line on the secondary side of the transformer T1 and
on the upstream side of the energy meter 20 is used as the first communication path
20 L1 and the power line communication is performed between the slave 10 and the
master 41, there is no need to form an additional communication path, and thus
installation of the slave 10 is facilitated. In contrast, in a case where electric wave
are used as the transmission medium defining the first communication path L1, the
communication between the slave 10 and the master 41 is enabled irrespective of the
25 distribution line.
[0080l
As illustrated in FIG. 2 and FIG. 3, the transmission media of the communication
between the slave 10 and the electric appliance 31 as well as the maintenance
30 terminal 50 are electric waves, and therefore particular work is unnecessary for
installing the slave 10 in the facility. By simply attaching the slave 10 to the energy
meter 20, it is possible to construct a so-called smart meter including a
communication function with the upper device 40 and a further communication
P642086
function with the electric appliance 31. Work of installing the slave 10 is easy, and
hence it is easy to construct the smart meter. In short, the smart meter is
constituted by the energy meter 20 and the slave (communication device) 10.
5 [00811
As described above, the smart meter can be constructed by attaching the slave 10, and
it is easy to change the specification of the slave 10. Thus, it is possible to ensure
extendability of functions. For example, a function for acting as a component of an
energy management system can be added to the slave 10 in addition to the function of
10 obtaining the meter-reading data, if necessary. In this case, the slave 10 can be used
for suppressing the power consumption of the electric appliance 31 used in the facility
1.
[00821
15 The slave 10 can communicate with the maintenance terminal 50, and the
maintenance terminal 50 can not only obtain the meter-reading data but also change
the parameters of the slave 10 and give instructions to the electric appliance 31.
The parameters of the slave 10 can be changed by use of the maintenance terminal 50,
and hence it is possible to adjust the parameters so that the communication is
20 optimized in accordance with environments of a site where the slave 10 is installed.
Moreover, the communication terminal 50 can provide instructions to the electric
appliance 31 used in the facility 1, and therefore it is possible to make adjustment for
enabling appropriate communication according to the site.
25 [00831
In order to allow the upper device 40 to identify one or more slaves 10, it is necessary
that identification information is allocated to individual slaves 10. For example,
such identification information is selected from an address used by the slave 10 to
communicate with the upper device 40, a product number uniquely given to the slave
30 10, and a MAC address given to the slave 10 with a communication function, for
example. It is sufficient that the identification information is uniquely allocated to
the slave 10 managed by the upper device 40. In summary, it is sufficient that the
identification information is unique with regard to the slaves 10 managed by the
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master 41. As shown in FIG. 4, the controller 100 of the slave 10 includes an
identification information holding unit 101 for holding the identification information.
In other words, the controller 100 includes the identification information holding unit
101 storing the identification information unique to the slave 10. For example, the
5 controller 100 is configured to, when receiving the identification information from the
upper device 40, store the received identification information in the identification
information holding unit 10 1.
[00841
10 The following explanation is made to an example in which the master 41 issues an
address for communication allocated to the slave 10 managed by the master 41 and
this address is used as the identification information.
[0085l
15 Accordingly, the address used by the slave 10 in the A-route communication is issued
by the master 41. In this example, the master 41 issues the address in response to
reception of an address request from the slave 10, and sends the issued address to the
slave 10 that has sent the address request. Additionally, the master 41 issues the
addresses for the slaves 10 in an order of reception of the address request. The
20 address is an integer indicative of a number of issuance.
[oossl
FIG. 5 shows an example in which the slaves 10 are individually situated in dwelling
units of a condominium, and numbers placed on right sides of the slaves 10 represent
25 the addresses issued by the master 41. Squares illustrated in FIG. 5 schematically
represent the dwelling units, and labels "room --" represent dwelling unit number.
In this example, the single master 41 is installed in the condominium, and collects the
meter-reading data from the slaves 10 individually installed in the dwelling units of
the condominium.
30
[00871
As described above, the master 41 allocates the addresses to the slaves 10 in the order
of reception of the address requests. As illustrated in FIG. 5, there is no relation
P642086
between a physical location of the dwelling unit represented by the dwelling unit
number and the address of the slave 10. As described above, if no relation between
the address and the dwelling unit number is required, a procedure of allocating the
addresses to the slaves 10 is facilitated and thus it can be easy to install the system.
5
[0088l
In this regard, a communication area of the slave 10 must be limited so that the slave
10 is allowed to communicate with the electric appliance 31 in the facility associated
with the slave 10 and is not allowed to communicate with the electric appliance 31 in
10 a neighboring facility. Further, an area in which the slave 10 and the maintenance
terminal 50 communicate with each other must be limited so that, in a period in
which the slave 10 communicates with the maintenance terminal 50, the maintenance
terminal 50 is not allowed to communicate with another slave 10. Well known
techniques of limiting communication areas may include a technique of selecting
15 channels used in communication areas, a technique of adjusting either the output
power at the transmission side or the reception sensitivity at the reception side, and a
technique of distributing encryption keys used in communication areas.
[00891
20 The limitation of the communication area may be required for not only a case in which
the second I@ 12 and the third I/F 13 use electric waves as the transmission media
but also the power line communication using the distribution line as the 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
25 described.
[00901
The slave 10 selects channels used in the second I@ 12 and the third I/F 13 from a
plurality of channels in a predetermined selectable range. Note that, normally, the
30 third I/F 13 is not used. In view of this, it is preferable that the third I/Fs 13 of all
the slaves 10 use the same channel and this channel be used by the second I/F 12
while the third I@ 13 is not used.
P642086
[009 11
The channel is defined by at least one of a frequency and a time slot. With regard to
the slave 10, channels to be used by the second IIF 12 and the third I/F 13 of the slave
10 are defined by parameters in the selectable range selected from various types of
5 frequencies, various types of time slots, or combinations of various types of
frequencies and various types of time slots. The slave 10 includes a channel selector
102 configured to select a channel used by the slave 10 from the plurality of channels
in the predetermined selectable range.
10 [00921
In summary, as shown in FIG. 4, the controller 100 of the slave 10 includes the
channel selector 102 configured to select a communication channel (first
communication channel) to be used for wireless communication by the third interface
unit 13 from the plurality of channels. Additionally, the channel selector 102 is
15 configured to designate a communication channel (second communication channel) to
be used for the wireless communication by the second interface unit 12. In the
present embodiment, the channel selector 102 selects the same channel, as the first
communication channel and the second communication channel.
20 [00931
It is sufficient that the channel selector 102 is configured to select from a plurality of
channels a communication channel used in the wireless communication of at least one
of the second interface unit 12 and the third interface unit 13.
25 [00941
Note that, the channel selector 102 may be configured to select communication
channel (third communication channel) used in the wireless communication of the
first interface unit 11 from a plurality of channels.
30 [00951
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.
[0096l
Before fixing the channel to be used, the slave 10 performs a prior process of
5 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
channel set in the prior process, changing the channel based on the evaluation result
if necessary. In summary, the slave 10 performs two processes including the prior
process and the subsequent process. In the prior process, the channel (hereinafter
10 referred to as "initial channel") is tentatively set, and in the subsequent process, the
initial channel is changed appropriately to avoid occurrence of interference.
[00971
The slave 10 includes an interference evaluator 103 configured to evaluate a degree of
15 interference in a case where the initial channel tentatively set is used, and a change
instructor 104 configured to instruct the channel selector 102 to change the channel
when there is a possibility of interference. In short, as shown in FIG. 4, the
controller 100 of the slave 10 includes the interference evaluator 103 and the change
instructor 104.
20
[00981
The interference evaluator 103 is configured to judge whether interference of electric
waves occurs in the communication channel (e.g., the first communication channel,
the second communication channel, and the third communication channel). For
25 example, the interference evaluator 103 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.
[00991
30 For the evaluation value for evaluating the degree of interference, a received signal
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
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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
numerical values as the evaluation values, indications for evaluating the degree of
interference can be obtained.
5
[o 1001
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 103 compares the evaluation value with the threshold. When the
10 evaluation value exceeds the threshold, the interference evaluator 103 determines
that the degree of interference is high and there is need to change the channel.
[o 10 11
The change instructor 104 is configured to provide the change instruction to the
15 channel selector 102 when the interference evaluator 103 determines that the
interference occurs. For example, when the interference evaluator 103 determines
that the change of the channel is necessary (i.e., the evaluation value exceeds the
threshold), the change instructor 104 instructs the channel selector 102 to change the
selected channel. Additionally, the change instructor 104 is configured to not provide
20 the change instruction to the channel selector 102 when the interference evaluator
103 determines that the interference does not occur. For example, when the
evaluation value is less than the threshold in the interference evaluator 103, the
change instructor 104 uses the channel selected by the channel selector 102 for
communication.
25
[o 1021
The channel selector 102 is configured to change the communication channel in
response to reception of the change instruction from the change instructor 104.
30 [01031
In particular, the channel selector 102 is configured to select from the plurality of
channels the initial channel as a candidate for the communication channel, depending
on the identification information stored in the identification information holding unit
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101. The channel selector 102 is configured to, when receiving the change
instruction from the change instructor 104, 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 102 is configured to, when not
5 receiving the change instruction from the change instructor 104, set the initial
channel as the communication channel.
[O 1041
In the following, a concrete example of the operation of the slave 10 is described using
10 the case shown in FIG. 5. This example of the operation is only an example, and
there is no intent to limit the operation of the slave 10, and therefore the slave 10 may
perform other alternative operation.
[01051
15 The illustrated instance shows a condition in which the master 41 issues the
identification information for the slave 10 in response to the address request from the
slave 10. The slave 10 holds the identification information issued by the master 41
in the identification information holding unit 101. In this operation example, the
channel selector 102 selects as the initial channel the channel corresponding to the
20 least significant digit of an integer of two digits held in the identification information
holding unit 101. In the illustrated instance, the identification information issued
under management of the master 41 is of two digits such as "02", "54", ..., "15", and
"23". The master 41 issues the identification information so as not to be same as the
identification information that has already been issued, and therefore the same
25 identification information is not issued under the management area of the master 41.
[O 1061
The channel selector 102 of the slave 10 uses the channel corresponding to the least
significant digit of the identification information as the initial channel, and therefore
30 the channel corresponding to a number of one digit, that is, "0" to "9" is set to the
initial channel as shown in FIG. 6. In the case of the instance illustrated in FIG. 5,
the same initial channel "04" is given to the room 102 and the room 202 adjacent in
the vertical direction, and the same initial channel "05" is given to the room 203 and
the room 303 adjacent in the vertical direction.
101071
Note that, the initial channel is selected by use of the least significant digit of the
5 identification information defined by an integer, buy 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
10 based on the remainder, the number of selectable channels depends on the value of
the divider.
[O 1081
As described, there is no relation between the position of the dwelling unit and the
15 identification information of the slave 10. Therefore, when the channel is selected
based on the least significant digit of the identification information, the same channel
is set to the slaves 10 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
10. When the slaves 10 using the same initial channel are installed adjacent to each
20 other, interference is likely to occur in communication.
10 1091
The slave 10 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 10
25 existing in an area in which the slave 10 can communicate. And, the slave 10 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 103. To detect the in-use channel, it is
necessary to measure the received signal strength indication for each channel.
30 Hence, the interference evaluator 103 sequentially in turn measures the received
signal strength indications of all the channels in the selectable range.
P642086
When the in-use channel is same as the channel to be used, interference is likely to
occur. Hence, the interference evaluator 103 of the slave 10 tries to detect another
slave 10 which uses a channel that is one of the detected in-use channels and is same
as the initial channel of the slave 10. In a process of measuring the received signal
5 strength indications of the individual channels, the slave 10 receives the identification
information as well as the channel of another slave 10. For example, the interference
evaluator 103 of the slave 10 receives packets outputted from the other slaves 10 to
evaluate the received signal strength indications, and extracts the identification
information of another slave 10 from the header of the received packet.
10 Consequently, the slave 10 obtains the identification information of another slave 10
that has the same initial channel as the slave 10 and gives the received signal
strength indication greater than the threshold.
[01111
15 In the example described herein, the identification information of the slave 10 is an
integer. When the same initial channel is set to the two or more slaves 10, the
interference evaluator 103 selects one slave 10 that is allowed to use this initial
channel from the two or more slaves 10 based on whether the identification
information is greater. When two or more other slaves 10 have the same initial
20 channel and give the received signal strength indications greater than the threshold,
the interference evaluator 103 determines whether the identification information is
greater than the other identification information. When the identification
information of the slave 10 is the smallest of the pieces of the identification
information of the other slaves 10, the interference evaluator 103 of the slave 10
25 allows the slave 10 to continue to use this initial channel as the communication
channel. Further, the interference evaluator 103 of the slave 10 requests the
channel selector 102 to change the channel by use of the change instructor 104 when
the identification information of the slave 10 is not the smallest of the pieces of the
identification information of the other slaves 10.
3 0
[01121
When the interference evaluator 103 intends to request the change instructor 104 to
change the channel, first the interference evaluator 103 tries to detect the channel
P642086
corresponding to the received signal strength indication equal to or less than the
judgment threshold from the channels in the selectable range. When the received
signal strength indication of the channel is equal to or less than the judgment
threshold, it can be considered that the channel is not used or interference is unlikely
5 to occur even when the channel is used. Hence, the detected channel is treated as
"available channel". When the available channel is detected, the interference
evaluator 103 provides information of the available channel to the change instructor
104. In summary, the interference evaluator 103 is configured to judge whether the
plurality of channels includes at least one available channel that does not cause
10 interference of the electric wave. The interference evaluator 103 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 104. Note that, in some cases, there is a plurality of available
channels. In such cases, the available channel information individually identifies the
15 plurality of available channels.
Lo1131
The change instructor 104 is configured to select a designated available channel to be
set as the communication channel (e.g., the first communication channel, the second
20 communication channel, and the third 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
102. For example, the change instructor 104 instructs the channel selector 102 to
change the channel after a lapse of a waiting time period determined based on the
25 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 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 10 selecting the different initial channels
30 select the same available channel.
10 1141
The channel selector 102 is configured to, when receiving the change instruction from
P642086
the change instructor 104, set the designated available channel indicated by the
change instruction as the communication channel.
[oi 151
5 The aforementioned channel selection techniques are collectively illustrated in FIG. 7.
In preprocessing, the channel selector 102 of the slave 10 in question selects the
initial channel corresponding to the least significant digit of the identification
information of the slave 10 in question defined by an integer (S 11). Thereafter, the
interference evaluator 103 of the slave 10 in question measures the received signal
10 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 interference evaluator 103 of the slave 10 in question obtains, from the header of
the packet, the identification information of another slave 10 whose in-use channel is
15 same as the initial channel of the slave 10 in question (S14). When another slave 10
whose in-use channel is same as the initial channel of the slave 10 in question is
present and interference is likely to be caused by the presence of this slave 10,
whether the identification information of this slave 10 is greater than the
identification information of the slave 10 in question is determined (S15).
20
[O 1161
When the identification information of the slave 10 is minimum (S15: Yes), use of the
initial channel is continued (S16). In contrast, when the identification information of
the slave 10 is not minimum (S15: No), the interference evaluator 103 evaluates the
25 received signal strength indications for all the channels to detect the available
channel (S17). When the available channels are detected, after a lapse of the
predetermined waiting time period (S181, the change instructor 104 instructs the
channel selector 102 to select, as the channel to be used by the second I/F 12, the
available channel corresponding to the smallest one of the numbers of the detected
30 available channels (S19). Through the aforementioned manner, the channel to be
used by the second I/F 12 is selected by the channel selector 102, and consequently the
slave 10 starts to operate by use of the selected channel (S20).
P642086
[01171
Even when the same initial channel is set to two or more slaves 10, the fact that the
same initial channel is set cannot be detected, provided that the header of the packet
outputted from any of these slaves 10 cannot be received by another slave 10. When
physical distances between the slaves 10 are relatively long, or there may be
partitions between the slaves 10, the received signal strength indication may be so
low that the slaves 10 cannot recognize the header of the packet from the others. In
this case, the comparison of the identification information of the slave 10 is not
performed even when interference is likely to occur.
[0118]
In other words, even when the same initial channel is set to two or more slaves 10,
provided that the slave 10 can communicate with the electric appliance 31 in the
facility associated with the slave 10 and the maintenance terminal 50 but cannot
15 communicate with the other slaves 10, the slave 10 can use the initial channel
without change.
[O 1 191
In view of this, the controller 100 of the slave 10 includes a communication quality
20 evaluator 105 configured to evaluate a communication quality through test
communication, and a power instructor 106 configured to adjust the output power of
the second I@ 12 and the output power of the third I/F 13.
10 1201
25 The communication quality evaluator 105 is configured to evaluate a communication
quality of the communication channel (first communication channel) selected by the
channel selector 102. For example, the communication quality evaluator 105 is
configured to conduct test communication by use of the communication channel (first
communication channel) selected by the channel selector 102 to evaluate the
30 communication quality (communication quality of the first communication channel) of
the communication path L3 between the slave 10 and the communication terminal 50.
P642086
The power instructor 106 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
communication quality evaluator 105 to satisfy a predetermined condition. For
5 example, the power instructor 106 is configured to decrease the intensity of the
electric wave (electric wave according to the communication channel) outputted from
the third interface unit 13 within a range in which the communication quality
(communication quality of the communication path L3) evaluated by the
communication quality evaluator 105 fulfills the predetermined condition.
10
101221
Further, the communication quality evaluator 105 is configured to evaluate a
communication quality of the communication channel (second communication
channel) selected by the channel selector 102. For example, the communication
15 quality evaluator 105 is configured to conduct test communication by use of the
communication channel (second communication channel) selected by the channel
selector 102 to evaluate the communication quality (communication quality of the
second communication channel) of the communication path L2 between the slave 10
and the electric appliance 31.
20
10 1231
In this case, the power instructor 106 is configured to set an intensity of an electric
wave allocated to the second communication channel to a lower limit of a range of
intensities allowing the communication quality (communication quality of the second
25 communication channel) evaluated by the communication quality evaluator 105 to
satisfy a predetermined condition. For example, the power instructor 106 is
configured to decrease the intensity of the electric wave (electric wave according to the
second communication channel) outputted from the second interface unit 12 within a
range in which the communication quality (communication quality of the
30 communication path L2) evaluated by the communication quality evaluator 105
fulfills the predetermined condition.
P642086
Additionally, the communication quality evaluator 105 is configured to evaluate a
communication quality of the communication channel (third communication channel)
selected by the channel selector 102. For example, the communication quality
evaluator 105 is configured to conduct test communication by use of the
5 communication channel (third communication channel) selected by the channel
selector 102 to evaluate the communication quality (communication quality of the
third communication channel) of the communication path L1 (L12) between the slave
10 and the upper device 40.
10 [01251
In this case, the power instructor 106 is configured to set an intensity of an electric
wave allocated to the third communication channel to a lower limit of a range of
intensities allowing the communication quality (communication quality of the third
communication channel) evaluated by the communication quality evaluator 105 to
15 satisfy a predetermined condition. For example, the power instructor 106 is
configured to decrease the intensity of the electric wave (electric wave according to the
third communication channel) outputted from the first interface unit 11 within a
range in which the communication quality (communication quality of the
communication path L12) evaluated by the communication quality evaluator 105
20 fulfills the predetermined condition.
Lo1261
After the slave 10 obtains the address for communication issued by the master 41 and
the initial channel is set, the slave 10 first performs test communication with the
25 electric appliance 31 in the facility managed by the slave 10 and test communication
with the maintenance terminal 50. Note that, in a process of setting the initial
channel to the slave 10, it is assumed that a person who installs the slave 10 carries
the maintenance terminal 50 and thus the maintenance terminal 50 is present in the
communication area of the slave 10.
3 0
[01271
The slave 10 conducting the test communication decreases the output power for
transmitting packets with time, and obtains communication statistic information
(communication quality) such as a communication error rate and a retransmission
rate. Additionally, this slave 10 decreases the output power down to an allowable
lower limit of the range in which the communication qualities with the electric
appliance 31 and the maintenance terminal 50 are kept good. As described above,
5 the output power of the slave 10 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 10. Moreover, the slave 10 decreases the output power down to
the allowable limit within the range in which the communication quality is kept good,
and therefore the communication quality with the electric appliance 31 in the facility
10 associated with the slave and the communication quality with the maintenance
terminal 50 can be maintained. As a result, a probability that the slave 10 changes
the initial channel is reduced, although the number of selectable channels is limited,
the channels can be set so as to avoid interference even when the number of slaves 10
is greater than the number of channels.
15
[01281
To enable communication between the slave 10 and the electric appliance 31 in the
facility associated with the slave 10, association (channel setting) between the slave
10 and the electric appliance 31 is necessary. The electric appliance 31 includes two
20 operation modes of a registration mode in which the channel is set to associate the
electric appliance 31 with the slave 10, and a normal mode in which the electric
appliance 31 operates by use of the set channel. For example, in the registration
mode, the electric appliance 31 selects all the channels sequentially in turn until the
electric appliance 31 receives the packet sent periodically from the slave 10.
25
[01291
In one example, the packet sent from the slave 10 includes information for identifying
the energy meter 20, and a worker inputs the information for identifying the
distribution circuit board 30 into the electric appliance 31. In this example, the
30 electric appliance 31 compares the information for identifying the energy meter 20 to
select the channel of the slave 10 of the facility in which the electric appliance 31 is
installed. Hence, the association between the slave 10 and the electric appliance 31
can be completed successfully. In the registration mode, the electric appliance 31
P642086
receives packets of all the channels, and therefore the electric appliance 31 may
receive the packet from the slave 10 in another facility. However, use of the
information for identifying the energy meter 20 can prevent association of the electric
appliance 31 with the slave 10 in another facility. When the selection of the channel
5 ends, the electric appliance 31 starts the normal mode and begins to communicate
with the slave 10 by use of the selected channel.
[O 1301
In contrast, for example, the maintenance terminal 50 is used by a meter reader who
10 visits for meter-reading. In this time, the maintenance terminal 50 communicates
with the slave 10 to obtain the meter-reading data including an integral value of
energy, and the like. Therefore, the channel setting between the slave 10 and the
maintenance terminal 50 is necessary in addition to the channel setting between the
slave 10 and the electric appliance 31.
15
[01311
The channel used by the maintenance terminal 50 is fixed. Hence, if the slave 10 is
prohibited to use the channel allocated to the maintenance terminal 50, the selectable
range of channels for the slave 10 is narrowed. In view of an efficiency of use of the
20 channels, it is not preferable that the number of selectable channels be limited and
nevertheless one channel be exclusively allocated to the maintenance terminal 50 that
is not used frequently.
[C) 1321
25 For this reason, the slave 10 of the present embodiment is configured to use the
channel allocated to the maintenance terminal 50 for communication with the electric
appliance 31 in a time period in which the third I/F 13 does not communicate with the
maintenance terminal 50. When acknowledging the start of use of the maintenance
terminal 50, the slave 10 that selects the channel to be used by the maintenance
30 terminal 50 allows the maintenance terminal 50 to use the channel, selects another
channel, and uses the selected channel.
P642086
The start of use of the maintenance terminal 50 can be acknowledged by receiving an
electric wave sent from the maintenance terminal 50 when the meter reader starts to
operate the maintenance terminal 50 in a vicinity of the slave 10. The maintenance
terminal 50 is used in the vicinity of the slave 10, and thus the slave 10 can receive an
5 electric wave having a relatively high electrical field intensity. Hence, the slave 10
can acknowledge the start of use of the maintenance terminal 50 by evaluating the
electric field intensity of the electric wave received by the third I&' 13. The
maintenance terminal 50 may send a packet for an entry request to the slave 10 at
the start of use so that the slave 10 receives the address of the maintenance terminal
10 50 included in the header of this packet.
101341
As for the slave 10 that selects the channel to be used by the maintenance terminal 50,
when the third In 13 acknowledges the start of use of the maintenance terminal 50,
15 the change instructor 104 instructs the channel selector 102 to select all the channels
sequentially in turn.
to1351
In the present embodiment, the third interface unit 13 is configured to judge whether
20 use of the communication terminal (maintenance terminal) 50 is started. The change
instructor 104 is configured to, when the third interface unit 13 determines that use
of the communication terminal 50 is started, provide 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 50. The channel
25 selector 102 is configured to, when receiving the change instruction from the change
instructor 104, change the second communication channel to the channel indicated by
the change instructor 104.
[0136]
30 Note that, the change instructor 104 may be configured to, when the third interface
unit 13 determines that use of the communication terminal 50 is started, provide 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 50.
The channel selector 102 is configured to, when receiving the change instruction from
the change instructor 104, change the third communication channel to the channel
indicated by the change instructor 104.
5 [01371
Additionally, the interference evaluator 103 monitors the received signal strength
indications of the individual channels in a period in which the change instructor 104
selects the channels sequentially in turn. The slave 10 detects the channel giving
the received signal strength indication equal to or less than the threshold (reference
10 value) as the available channel, and assigns the available channel as the channel used
by the second I/F 12.
[0 1 381
For example, it is assumed that the maintenance terminal 50 uses the channel "0".
15 In this example, as shown in FIG. 8, when the identification information of the slave
10 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 12 of the slave 10 is also the channel designated by "0".
As a result, the slave 10 of the room 201 uses the channel same as the channel used
20 by the maintenance terminal 50, for communication with the electric appliance 31.
[O 1391
In the allocation instance shown in FIG. 5, the channel "1" is not used by any slave 10,
and it is assumed that the received signal strength indications of the channels used in
25 the rooms 103, 203, and 303 at the slave 10 of the room 201 are too low to cause
interference. When the channels are allocated to the individual slaves 10 as shown
in FIG. 8, the available channels detected by the slave 10 of the room 201 are the four
channels "l"",6 ", "B", and "9".
30 [(31401
When the third I F 13 of the slave 10 of the room 201 acknowledges the start of use of
the maintenance terminal 50, the change instructor 104 of this slave 10 assigns a
right of using the channel "0" currently assigned to the second I/F 12 to the
P642086
maintenance terminal 50, and searches the available channels for the channel for
communication with the electric appliance 31.
[01411
5 The available channels of the slave 10 are the four channels "I", "6", "8",a nd "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 10 selects the channel "1" as the
channel (second communication channel) for communication with the electric
appliance 31 as shown in FIG. 9. The rule for the slave 10 to select the channel may
10 be appropriately determined, and for example the slave 10 can select another
available channel.
[o 1421
The slave 10 changes the channel for communication with the electric appliance 31,
and hence the slave 10 sends a preliminary notice to the electric appliance 31 before
changing the channel, to instruct the electric appliance 31 to also change the channel.
Note that, the association between the electric appliance 31 and the slave 10 is
necessary. For this reason, the information for identifying the energy meter 20 is
included in the packet sent from the slave 10 to the electric appliance 31 to give an
instruction of change of the channel, and thus the electric appliance 31 can confirm
that the slave 10 is a communication partner.
Lo1431
The slave 10 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 50. Further, before selecting the pre-change channel, the slave 10 provides
a preliminary notice regarding the change of the channel to the electric appliance 31.
As described above, the slave 10 that normally uses the same channel as the
maintenance terminal 50 changes temporarily the normally used channel to
communicate with the maintenance terminal 50. The process allows the slave 10 to
normally use the channel same as the channel used by the maintenance terminal 50,
and thus the efficiency of use of channels of the slave 10 can be improved.
[O 1441
Moreover, it is desirable that the slave 10 instruct the electric appliance 31 in the
facility associated with the slave 10 and the maintenance terminal 50 carried by the
person who installs the slave 10, to perform test communication similar to the test
communication performed by the slave 10. While the electric appliance 31 and the
maintenance terminal 50 perform the test communication, the communication quality
evaluator 105 of the slave 10 giving the instruction of the test communication
monitors the received signal strength indications relating to the electric appliance 31
and the maintenance terminal 50, and obtains the communication qualities from the
electric appliance 31 and the maintenance terminal 50. For example, the
communication quality is communication statistic information such as a
communication error rate and a retransmission rate.
Lo1451
The communication quality evaluator 105 of the slave 10 makes evaluation by
comparing at least one of the received signal strength indication and the
communication quality with a threshold, and accordingly instructs the electric
appliance 31 and the maintenance terminal 50 to reduce the output power to the
allowable lower limit. In this manner, when the slave 10 sets the channel, the
transmission power of each of the electric appliance 31 and the maintenance terminal
50 is reduced to an allowable lower limit. Therefore, the possibility that the electric
appliance 31 in one facility and the maintenance terminal 50 are associated with the
slave 10 of another facility is reduced. Consequently, it is possible to avoid
occurrence of interference of the electric appliance 31 of one facility and the
maintenance terminal 50 with the slave 10 of another facility.
[01461
As described above, the slave 10 of the energy management system of the present
embodiment is a slave of an energy management system, which is attached to the
energy meter 20 for measuring the energy consumed in the facility 1 and has a
function of transmitting to the upper device 40 the meter-reading data including an
amount of the energy measured by the energy meter 20. The slave 10 includes the
first interface unit 11, the second interface unit 12, and the third interface unit 13.
P642086
The first interface unit 11 is configured to communicate with the master 41 through
the first communication path L1. The second interface unit 12 is configured to
perform wireless communication with the electric appliance 31, that is one of electric
appliances used in the facility 1 and has the communication function, through the
5 second communication path L2 in which electric waves are used as the transmission
medium. The third interface unit 13 is configured to perform wireless
communication with the maintenance terminal 50 having at least a function of
obtaining the meter-reading data through the third communication path L3 in which
electric waves are used as the transmission medium. The second interface unit 12
10 and the third interface unit 13 are configured to perform communication in different
schemes (wireless communication schemes) so that the second communication path L2
and the third communication path L3 are communication paths independent from
each other.
15 Lo1471
Further, in the slave 10 of the energy management system of the present embodiment,
the first interface unit 11 uses, as the transmission medium of the first
communication path L1, the distribution line 60 on the upstream side of the energy
meter 20, to perform the power line communication with the upper device 40. In this
20 case, in the slave 10 of the energy management system of the present embodiment,
the first communication path L1 is defined by the distribution line 60 (second path 62)
that is on the secondary side of the transformer T1 for transmitting commercial power
to the facility 1 and is on the upstream side of the energy meter 20.
25 [01481
Moreover, in the slave 10 of the energy management system of the present
embodiment, the first interface unit 11 uses electric waves as the transmission
medium of the first communication path L1 to perform wireless communication with
the upper device 40. In this case, the first interface unit 11 and the third interface
30 unit 13 may perform communication in the same scheme so that the first
communication path L1 and the third communication path L3 are the same
communication path. Alternatively, the first interface unit 11 and the second
interface unit 12 may perform communication in the same scheme so that the first
communication path L1 and the second communication path L2 are the same
communication path.
[O 1491
5 Furthermore, with regard to the slave 10 of the energy management system of the
present embodiment, the upper device 40 includes the upper server 42 and the master
41. The upper server 42 is a server computer configured to collect the meter-reading
data from the energy meters 20 of the plurality of facilities 1 in a management area.
The master 41 has the communication function with the upper server 42 and is
10 configured to send to the upper server 42 the meter-reading data obtained from at
least one of the facilities 1.
[O 1501
Additionally, the slave 10 of the energy management system of the present
15 embodiment further includes the channel selector 102, the interference evaluator 103,
and the change instructor 104. The channel selector 102 is configured to select the
communication channels used by the second interface unit 12 and the third interface
unit 13 from channels in the predetermined selectable range. The interference
evaluator 103 is configured to evaluate the degree of interference through comparison
20 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 102 is used.
The change instructor 104 is configured to instruct the channel selector 102 to change
the channel when the evaluation value is in a range, defined by the threshold, in
which the degree of interference is relatively high.
25
[01511
Moreover, the slave 10 of the energy management system of the present embodiment
further includes the identification information holding unit 101 configured to hold the
identification information that is unique within the management area of the upper
30 device 40. The channel selector 102 is configured to specify the channel based on the
identification information held in the identification information holding unit 101 by
use of the predetermined rule, and select the specified channel as the initial channel.
The identification information holding unit 101 is configured to select the channel
P642086
different from the initial channel as the communication channel when receiving the
change instruction from the change instructor 104, and to select the channel same as
the initial channel as the communication channel when not receiving the change
instruction from the change instructor 104.
5
[01521
Further, in the slave 10 of the energy management system of the present embodiment,
the change instructor 104 is configured to instruct the channel selector 102 to change
the channel used by the second interface unit 12 from the current channel to an
10 available channel that is less likely to cause interference when the third interface unit
13 acknowledges the start of use of the maintenance terminal 50 in a case where the
channel used by the second interface unit 12 is same as the channel used by the
maintenance terminal 50.
15 [01531
Moreover, the slave 10 of the energy management system of the present embodiment
further includes the communication quality evaluator 105 and the power instructor
106. The communication quality evaluator 105 is configured to perform test
communication by use of the channel selected by the channel selector 102 to evaluate
20 the communication quality between the slave 10 and the electric appliance 31 through
the communication path (second communication path L2). The power instructor 106
is configured to decrease the output power of the second interface unit 12 down to the
allowable lower limit within the range in which the communication quality is kept
fine.
2 5
[O 1541
Additionally, in the slave 10 of the energy management system of the present
embodiment, the interference evaluator 103 has a function of detecting an available
channel which is less likely to cause interference from the channels in the selectable
30 range, and thereafter of providing the information of the detected available channel to
the change instructor 104. The change instructor 104 is configured to instruct the
channel selector 102 to change the current channel to one selected from the available
channels indicated by the information provided from the interference evaluator 103.
[01551
Furthermore, in the slave 10 of the energy management system of the present
embodiment, the channel selector 102 may select a frequency used for communication.
5 Alternatively, the channel selector 102 may select a time slot used for communication.
Alternatively, the channel selector 102 may select a combination of a frequency and a
time slot used for communication.
[O 1561
10 Additionally, with regard to the slave 10 of the energy management system of the
present embodiment, the identification information held in the identification
information holding unit 101 is given by the upper device 40.
[01571
15 In other words, the slave 10 of the energy management system of the present
embodiment includes the following first to fifteenth features. Note that, the second
to fifteenth features are optional.
[O 1581
20 In the first feature, the slave 10 is a slave suitable for energy management systems
for collecting, from the energy meter 20 for measuring an amount of electric energy
supplied from the power source 70 to the predetermined place (facility 1) through the
distribution line 60, the meter-reading data containing the amount of electric energy.
The slave 10 includes the first interface unit 11, the second interface unit 12, the
25 third interface unit 13, and the controller 100. The first interface unit 11 is
configured to communicate with the upper device 40. The second interface unit 12 is
configured to communicate with the electric appliance 31 installed in the
predetermined place (facility 1). The third interface unit 13 is configured to
communicate with the communication terminal 50. The controller 100 has: the
30 function of obtaining the meter-reading data from the energy meter 20; the function of
controlling the first interface unit 11 to send the meter-reading data to the upper
device 40; and the function of controlling the third interface unit 13 to send the
meter-reading data to the communication terminal 50. The second interface unit 12
P642086
and the third interface unit 13 are configured to perform wireless communication
using electric waves in wireless communication schemes different from each other.
10 1591
5 In the second feature based on the first feature, the wireless communication schemes
are protocols.
[OI~OI
In the third feature based on the first or second feature, the first interface unit 11 is
10 connected to the upper device 40 through the distribution line 60, and is configured to
perform power line communication with the upper device 40 through the distribution
line 60.
[01611
15 In the fourth feature based on the third feature, the energy meter 20 is connected to
the power source 70 through the transformer T1 configured to adjust electricity from
the power source 70 to electricity appropriate to the predetermined place. The
distribution line 60 includes the first path 61 between the power source 70 and the
transformer TI, and the second path 62 between the transformer T1 and the energy
20 meter 20. The upper device 40 is connected to the second path 62. The first
interface unit 11 is configured to perform power line communication with the upper
device 40 through the second path 62.
10 1621
25 In the fifth feature based on any one of the first to fourth features, the first interface
unit 11 is configured to perform wireless communication using an electric wave with
the upper device 40.
101631
30 In the sixth feature based on the fifth feature, the first interface unit 11 and the third
interface unit 13 are configured to perform wireless communication in the same
wireless communication scheme.
[O 1641
In the seventh feature based on the fifth feature, the first interface unit 11 and the
second interface unit 12 are configured to perform wireless communication in the
same wireless communication scheme.
[01651
In the eighth feature based on any one of the first to seventh features, the controller
100 includes the channel selector 102, the interference evaluator 103, and the change
instructor 104. The channel selector 102 is configured to select a communication
10 channel to be used for the wireless communication of at least one of the second
interface unit 12 and the third interface unit 13, from a plurality of channels. The
interference evaluator 103 is configured to judge whether interference of electric
waves occurs in the communication channel. The change instructor 104 is configured
to provide a change instruction to the channel selector 102 when the interference
15 evaluator 103 determines that the interference occurs. The channel selector 102 is
configured to change the communication channel in response to reception of the
change instruction from the change instructor 104.
[01661
20 In the ninth feature based on the eighth feature, the controller 100 includes the
identification information holding unit 101 storing identification information unique
to the slave 10. The channel selector 102 is configured to select from the plurality of
channels an initial channel as a candidate for the communication channel, depending
on the identification information stored in the identification information holding unit
25 101. The channel selector 102 is configured to, when receiving the change
instruction from the change instructor 104, 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 102 is configured to, when not
receiving the change instruction from the change instructor 104, set the initial
30 channel as the communication channel.
[O 1671
In the tenth feature based on the eighth or ninth feature, the interference evaluator
103 is configured to judge whether the plurality of channels includes at least one
available channel that does not cause interference of the electric wave. The
interference evaluator 103 is configured to, when determining that the plurality of
channels includes the available channel, provide available channel information
5 identifying the at least one available channel to the change instructor 104. The
change instructor 104 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 102. The channel selector 102 is
10 configured to, when receiving the change instruction from the change instructor 104,
set the designated available channel indicated by the change instruction as the
communication channel.
[O 1681
15 In the eleventh feature based on any one of the eighth to tenth features, the controller
100 further includes the communication quality evaluator 105 and the power
instructor 106. The communication quality evaluator 105 is configured to evaluate
the communication quality of the communication channel selected by the channel
selector 102. The power instructor 106 is configured to set the intensity of the
20 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 evaluator 105 to satisfy a predetermined condition.
[01691
25 In the twelfth feature based on any one of the eighth to eleventh features, the
communication channel is a channel to be used in the wireless communication of the
third interface unit 13. The channel selector 102 is configured to select the second
communication channel to be used in the wireless communication of the second
interface unit 12, from a plurality of channels. The third interface unit 13 is
30 configured to judge whether use of the communication terminal 50 is started. The
change instructor 104 is configured to, when the third interface unit 13 determines
that use of the communication terminal 50 is started, provide to the channel selector
102 the change instruction that indicates, as the second communication channel, a
P642086
channel that does not cause interference with a channel used by the communication
terminal 50. The channel selector 102 is configured to, when receiving the change
instruction from the change instructor 104, change the second communication channel
to the channel indicated by the change instructor 104.
[O 1701
In the thirteenth feature based on any one of the eighth to twelfth features, each of
the plurality of channel is defined by a frequency, a time slot, or a combination of a
frequency and a time slot.
10
[01711
In the fourteenth feature based on the ninth feature, the identification information is
given by the upper device 40 to the slave 10.
15 [01721
In the fifteenth feature based on any one of the first to fourteenth features, the slave
10 is attached to the energy meter 20.
lo1731
20 According to the slave 10 of the energy management system of the present
embodiment described above, the slave 10 attached to the energy meter 20 has the
function of communicating with the electric appliance 31 used in the facility 1 in
addition to the function of communicating with the upper device 40 and the
communication terminal 50, and hence it is possible to enable the energy
25 management in addition to the meter-reading. Additionally, the slave 10 is
configured to perform wireless communication with the communication terminal 50
and the electric appliance 31 and therefore installation of the slave 10 can be
facilitated, and furthermore the slave 10 is configured to perform such wireless
communication with the communication terminal 50 and the electric appliance 31 in
30 different schemes and thus interference of communication can be prevented.
[O 1741
Further, the energy management system of the present embodiment includes the
P642086
master 41, the slave 10, and the communication terminal 50. The master 41 has the
function of communicating with the upper server 42 for obtaining the meter-reading
data including the amount of energy measured by the energy meter 20 from the
facility 1 in the management area, and has the function of transmitting the
5 meter-reading data collected Gom at least one facility 1 to the upper server 42. The
slave 10 is attached to the energy meter 20 and has the function of transmitting the
meter-reading data to the master 41. The maintenance terminal 50 has the function
of communicating with the slave 10 to obtain the meter-reading data. The slave 10
includes the first interface unit 11, the second interface unit 12, and the third
10 interface unit 13. The first interface unit 11 is configured to communicate with the
master 41 through the first communication path L1. The second interface unit 12 is
configured to perform wireless communication with the electric appliance 31, that is
one of electric appliances used in the facility 1 and has the communication function,
through the second communication path L2 in which electric waves are used as the
15 transmission medium. The third interface unit 13 is configured to perform wireless
communication with the maintenance terminal 50 having at least a function of
obtaining the meter-reading data through the third communication path L3 in which
electric waves are used as the transmission medium. The second interface unit 12
and the third interface unit 13 are configured to perform communication in different
20 schemes so that the second communication path L2 and the third communication path
L3 are communication paths independent from each other.
[01751
In other words, the energy management system of the present embodiment includes
25 the following sixteenth to eighteenth features. Note that, the seventeenth and
eighteenth features are optional.
[01761
In the sixteenth feature, the energy management system includes the slave 10, the
30 upper device 40, and the communication terminal 50. The slave 10 is configured to
obtain, from the energy meter 20 for measuring an amount of electric energy supplied
from the power source 70 to the predetermined place through the distribution line 60,
the meter-reading data containing the amount of electric energy. The upper device
40 is configured to obtain the meter-reading data from the slave 10. The
communication terminal 50 is configured to obtain the meter-reading data from the
slave 10. The slave 10 includes the first interface unit 11, the second interface unit
12, the third interface unit 13, and the controller 100. The first interface unit 11 is
5 configured to communicate with the upper device 40. The second interface unit 12 is
configured to communicate with the electric appliance 31 installed in the
predetermined place (facility 1). The third interface unit 13 is configured to
communicate with the communication terminal 50. The controller 100 has: the
function of obtaining the meter-reading data from the energy meter 20; the function of
10 controlling the first interface unit 11 to send the meter-reading data to the upper
device 40; and the function of controlling the third interface unit 13 to send the
meter-reading data to the communication terminal 50. The second interface unit 12
and the third interface unit 13 are configured to perform wireless communication
using electric waves in wireless communication schemes different from each other.
15
101771
In the seventeenth feature based on the sixteenth feature, the upper device 40
includes the master 41 connected to the distribution line 60 and the upper server 42
connected to the master 41. The master 41 has the function of obtaining the
20 meter-reading data from the slave 10, and the function of sending the meter-reading
data obtained from the slave 10 to the upper server 42. The upper server 42 is
configured to store the meter-reading data received from the master 41.
[O 1781
25 In the eighteenth feature based on the sixteenth or seventeenth feature, the
communication terminal 50 has the function of communicating with the electric
appliance 3 1.
[01791
30 According to the energy management system of the present embodiment described
above, the slave 10 attached to the energy meter 20 has the function of
communicating with the electric appliance 31 used in the facility 1 in addition to the
function of communicating with the upper device 40 and the communication terminal
P642086
50, and hence it is possible to enable the energy management in addition to the
meter-reading. Additionally, the slave 10 is configured to perform wireless
communication with the communication terminal 50 and the electric appliance 31 and
therefore installation of the slave 10 can be facilitated, and furthermore the slave 10
5 is configured to perform such wireless communication with the communication
terminal 50 and the electric appliance 31 in different schemes and thus interference of
communication can be prevented.
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, and
the second interface unit and the third interface unit being configured to
perform wireless communication using electric waves in wireless communication
schemes different from each other.
20
2. The slave suitable for energy management systems according to claim 1, wherein
the wireless communication schemes are protocols.
3. The slave suitable for energy management systems according to claim 1, wherein
2 5 the first interface unit is connected to the upper device through the
distribution line, and 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:
30 the energy 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
- 53 -
P642086
transformer, and a second path between the transformer and the energy meter;
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
the first interface unit is configured to perform wireless communication using
an electric wave with the upper device.
10 6. The slave suitable for energy management systems, according to claim 5, wherein
the first interface unit and the third interface unit are configured to perform
wireless communication in the same wireless communication scheme.
7. The slave suitable for energy management systems, according to claim 5, wherein
15 the first interface unit and the second interface unit are configured to perform
wireless communication in the same wireless communication scheme.
8. The slave suitable for energy management systems, according to claim 1, wherein:
the controller includes
2 0 a channel selector configured to select a communication channel to be
used for the wireless communication of at least one of the second interface unit and
the third interface unit, from a plurality of channels,
an interference evaluator configured to judge whether interference of
electric waves occurs in the communication channel, and
2 5 a change instructor configured to provide a change instruction to the
channel selector when the interference evaluator determines that the interference
occurs; and
the channel selector is configured to change the communication channel in
response to reception of the change instruction from the change instructor.
3 0
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
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
5 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;
and
the channel selector is configured to, when not receiving the change
instruction from the change instructor, set the initial channel as the communication
10 channel.
10. The slave suitable for energy management systems, according to claim 8, wherein:
the interference evaluator is configured to judge whether the plurality of
channels includes at least one available channel that does not cause interference of
15 the electric wave;
the interference evaluator 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;
the change instructor is configured to select a designated available channel to
20 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; and
the channel selector is configured to, when receiving the change instruction
from the change instructor, set the designated available channel indicated by the
25 change instruction as the communication channel.
11. The slave suitable for energy management systems, according to claim 8, wherein
the controller further includes
a communication quality evaluator configured to evaluate a
30 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
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 in the wireless
communication of the third interface unit;
the channel selector is configured to select a second communication channel to
be used in the wireless communication of the second interface unit, from a plurality of
channels;
10 the third interface unit is configured to judge whether use of the
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,
15 a channel that does not cause interference with a channel used by the communication
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.
2 0
13. The slave suitable for energy management systems according to claim 8, wherein
each of the plurality of channel is defined by a frequency, a time slot, or a
combination of a frequency and a time slot.
25 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.
15. The slave suitable for energy management systems according to claim 1, wherein
the slave is attached to the energy meter.
30
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
distribution line, meter-reading data containing the amount of electric energy!
an upper device configured to obtain the meter-reading data from the slave;
a communication terminal configured to obtain the meter-reading data from
the slave,
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 terminal; and
a controller having: a function of obtaining the meterreadingdata 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, and
the second interface unit and the third interface unit being configured to
perform wireless communication using electric waves in wireless communication
schemes different from each other.
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,
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.
18. The energy management system according to claim 16, wherein
the communication terminal has a function of communicating with the electric
appliance.