JPWO2014156156A1 - Energy meter, energy metering system - Google Patents

Abstract

The watt-hour meter 10 measures the amount of power used by the customer 1, communicates with the parent device 20 through the first communication network NT1, and communicates with the device 30 provided in the customer 1 through the second communication network NT2. Configured to do. The watt-hour meter 10 includes a communication interface unit 11 and a control unit 12. The communication interface unit 11 transmits / receives a radio signal, and a channel determined by the frequency of the radio signal can be selected from a plurality of types. Shared. The control unit 12 controls the communication interface unit 11 so as to provide a period for performing communication in the first communication network NT1 and a period for performing communication in the second communication network NT2.

Description

  The present invention relates to a watt hour meter installed in a consumer and having a function of measuring the amount of power used and a communication function, and a power metering system including the watt hour meter.

  Conventionally, a watt-hour meter having a function of measuring the amount of power used by a consumer and a communication function has been proposed (for example, Japanese Patent Application Publication No. 2011-103726 (hereinafter referred to as Document 1)). The watt-hour meter described in Literature 1 includes a wide-area communication unit for connecting to a wide-area network and a short-range communication unit for performing communication between a load device and a sensor device installed in a house.

  As for the watt-hour meter having a communication function, a configuration that enables connection to two types of communication networks is known as in the technique described in Document 1. However, in order to connect to two types of communication networks, two communication interface units having different specifications are required, resulting in an increase in cost.

  It is an object of the present invention to provide a watt-hour meter that enables communication with two types of communication networks without using two communication interface units, resulting in cost reduction. An object of the present invention is to provide a power metering system including a power meter.

  The watt-hour meter according to the present invention is provided for each consumer, and is provided in the consumer with a function of measuring the amount of power used by the consumer, a function of communicating with a parent device through a first communication network, and the consumer. A watt-hour meter having a function of communicating with a connected device through a second communication network, wherein a radio signal using radio waves as a transmission medium is transmitted and received, and a channel defined by the frequency of the radio signal can be selected from a plurality of types. And a communication interface unit shared in communication in the first communication network and communication in the second communication network, a communication period in the first communication network, and a communication period in the second communication network. And a control unit that controls the communication interface unit.

  In this watt-hour meter, the control unit is configured such that the first channel used in the reception waiting period in the first communication network is the same as the second channel used in the reception waiting period in the second communication network. It is preferable to control the communication interface unit so as to share the same.

  In this watt-hour meter, the control unit is configured to notify the first communication network of information related to the first channel used during a reception waiting period in the first communication network. Is preferably controlled.

  In this watt-hour meter, when the control unit receives information on the second channel determined by the base unit through the communication interface unit, the control unit sets the first channel to the same channel as the second channel. In addition, it is preferable to control the communication interface unit.

  In this watt-hour meter, the control unit uses different channels for the first channel used in the reception waiting period in the first communication network and the second channel used in the reception waiting period in the second communication network. And the communication interface unit is controlled to include a period during which the first channel is selected and a period during which the second channel is selected every predetermined time shorter than a communication frame. preferable.

  In this watt-hour meter, when it is determined that the control unit has received a predetermined signal indicating start of reception during the reception waiting period, the control unit has received the predetermined signal out of the first channel and the second channel. It is preferable to continue communication using the channel.

  In this watt-hour meter, it is preferable that the control unit determines that the predetermined signal has been received when the received signal level is equal to or higher than a prescribed threshold value.

  In the watt-hour meter, it is preferable that the control unit determines that the predetermined signal has been received when bit synchronization is established in a part of the preamble included in the frame.

  In the watt-hour meter, it is preferable that the control unit determines that the predetermined signal has been received when frame synchronization is established by detecting a unique word included in the frame.

  The electric energy metering system according to the present invention includes any one of the watt-hour meters described above, a master unit that communicates with the watt-hour meter through the first communication network, and the second communication network provided in the consumer. And a device that communicates with the watt-hour meter.

  According to the configuration of the present invention, one communication interface unit is shared by the first communication network and the second communication network. Therefore, two types of communication networks can be communicated without using two communication interface units. There is an advantage that the cost can be reduced as a result.

1 is a block diagram illustrating a first embodiment. FIG. 6 is an operation explanatory diagram using a time chart for the first embodiment. FIG. 6 is an operation explanatory diagram using a sequence diagram for the first embodiment. FIG. 9 is an operation explanatory diagram using a time chart for another example of the operation of the first embodiment. FIG. 10 is an operation explanatory diagram using a time chart for the second embodiment. FIG. 10 is an operation explanatory diagram using a time chart for another operation example of the second embodiment.

(Embodiment 1)
As shown in FIG. 1, the watt-hour meter system described in the following embodiment includes a watt-hour meter 10 installed for each power consumer 1, a parent device 20 that communicates with the watt-hour meter 10, and a consumer. 1 and a device 30 that communicates with the watt-hour meter 10. The electricity meter 10 has a function of measuring the amount of power used by the customer 1.

  The master unit 20 acquires the amount of power used by the watt-hour meter 10 and notifies the host device 40 operated by an electric power company or the like of the remote meter reading function, the power saving request (demand response) from the host device 40 A function of notifying the electricity meter 10 of such information.

  The base unit 20 can manage a plurality of watt-hour meters 10. For example, in the case of an apartment house or a tenant building, the watt-hour meter 10 installed in each dwelling unit or each tenant is managed by one or several master units 20. In the case of a detached house, the power meter 10 installed in each of the plurality of houses is managed by the master unit 20. That is, the base unit 20 can collectively manage a plurality of watt-hour meters 10 and functions as a concentrator for the watt-hour meters 10.

  The watt-hour meter 10 constructs a multi-hop wireless network using radio waves as a transmission medium with the parent device 20. That is, the watt-hour meter 10 and the parent device 20 construct an ad hoc network in which another watt-hour meter 10 can be used for relaying during communication and the communication path is changed according to the communication environment. Below, the communication network constructed | assembled with the main | base station 20 and the watt-hour meter 10 is made into 1st communication network NT1.

  The device 30 is a device having a communication function among various devices installed in the customer 1, and in particular, a HEMS (Home Energy Management System) that manages the operation state of other devices installed in the customer 1. ) Desirably a controller. Other equipment means lighting equipment, air conditioning equipment, audiovisual equipment, kitchen equipment, and the like. Note that the watt-hour meter 10 may be configured to directly communicate with a device having another communication function without using the HEMS controller. The watt-hour meter 10 performs wireless communication using radio waves as a transmission medium when communicating with the device 30.

  Hereinafter, a communication network constructed by the watt-hour meter 10 and the device 30 is referred to as a second communication network NT2. It is assumed that the watt-hour meter 10 communicates only with the HEMS controller. Therefore, in the following, the device 30 means a HEMS controller.

  As described above, since the watt-hour meter 10 performs wireless communication with the device 30, when the watt-hour meter 10 of the neighboring consumer 1 uses the same channel in the second communication network NT2, There is a possibility that radio signal leakage or interference occurs between different consumers 1. Channels are divided by frequency. Therefore, it is desirable to use a different frequency for each consumer 1 in the nearby consumer 1 where radio signal interference may occur. However, the same frequency may be used even if there is no interference in the nearby consumer 1.

  As described above, the watt-hour meter 10 can communicate through both the first communication network NT1 and the second communication network NT2, and functions to communicate with the parent device 20 through the first communication network NT1. And a function of communicating with the device 30 through the second communication network NT2. Further, the watt-hour meter 10 also has a function of transferring information between the first communication network NT1 and the second communication network NT2. Therefore, the watt-hour meter 10 can notify the device 30 of information from the host device 40 transmitted from the parent device 20 through the first communication network NT1, and from the device 30 to the second communication network. Information transmitted through NT2 can be notified to the host device 40.

  Next, the configuration of the watt-hour meter 10 will be described. The watt-hour meter 10 includes a communication interface unit 11 that is shared by communication in the first communication network NT1 (so-called A route communication) and communication in the second communication network NT2 (so-called B route communication). Hereinafter, the communication interface unit is abbreviated as “communication I / F unit”. The communication I / F unit 11 includes a channel selection unit 111 so that a desired channel can be selected from a plurality of (for example, about 5 to 10) channels. The channel selection unit 111 is controlled by the control unit 12, and the control unit 12 selects a channel.

  The communication I / F unit 11 is normally in a waiting state for reception, and transitions to a reception state when a signal is received, and transitions to a transmission state when performing a response to reception of a signal or a reply to a request notified by the signal. . Further, the communication I / F unit 11 returns to the reception waiting state when the reception state or the transmission state ends. In the embodiment described below, the communication I / F unit 11 is shared for reception waiting in the first communication network NT1 and reception waiting in the second communication network NT2.

  In the present embodiment, the watt-hour meter 10 uses a channel (first channel) used for a reception waiting period in the first communication network NT1 and a channel (second channel) used for reception waiting in the second communication network NT2. ) And the same frequency channel are used. That is, the control unit 12 controls the channel selection unit 111 so that the same frequency is selected without distinguishing between the first communication network NT1 and the second communication network NT2 during the reception waiting period. The frequency selected outside the reception waiting period in the communication in the first communication network NT1 will be described later.

  Channels used for reception waiting in the first communication network NT1 and the second communication network NT2 are monitored by the watt-hour meters 10 for interference from the other watt-hour meters 10, so that each watt-hour meter 10 Determine autonomously. In addition, you may employ | adopt the structure which the main | base station 20 determines the channel which the watt-hour meter 10 uses for reception waiting in 2nd communication network NT2. That is, the control unit 12 receives information on the channel notified from the parent device 20 to each watt hour meter 10 through the communication I / F unit 11, and uses this channel for reception waiting in the second communication network NT2. Used as In the present embodiment, the first communication network NT1 and the second communication network NT2 use the same channel for reception waiting.

  By the way, as described above, if the nearby consumer 1 uses the same frequency for communication between the watt hour meter 10 and the device 30, there is a possibility that radio signal leakage or interference may occur. Needs to know the frequency used by the nearby consumer 1. Therefore, the control part 12 has a function which notifies the watt-hour meter 10 of the other consumer 1 of the frequency used for reception waiting in the 1st communication network NT1. That is, the control unit 12 controls the communication I / F unit 11 so as to notify the first communication network NT1 of information regarding the first channel.

  When the watt-hour meter 10 notifies the information about the first channel, another watt-hour meter 10 belonging to the first communication network NT1 is selected by the watt-hour meter 10 to wait for reception in the first communication network NT1. Recognize the frequency being used. As described above, the controller 12 recognizes the frequency used by the other watt-hour meters 10 to wait for reception in the first communication network NT1, so that the control unit 12 and the wireless signal used by the other customer 1 The frequency can be determined so as to avoid the interference.

  Note that the first communication network NT1 constructs a multi-hop wireless network, so packets such as keep alive and route search are exchanged regularly or irregularly between the watt-hour meters 10. Therefore, when determining the frequency to be used for the first communication network NT1, the control unit 12 uses these packets to notify the determined frequency to the other watt-hour meters 10 and the master unit 20. Also good.

  Hereinafter, an operation example of the above-described configuration will be shown. The watt-hour meter 10 communicates with other watt-hour meters 10 except when communicating with the parent device 20 in one hop. Here, assuming that the watt-hour meter 10 communicates in the first communication network NT1, the case where the watt-hour meter 10 of interest communicates with another watt-hour meter 10 on the upper side (base unit 20 side) is assumed. explain. However, even if the watt-hour meter 10 is the watt-hour meter 10 that communicates with the parent device 20 in one hop, the basic operation is the same as when communicating with the higher-level watt-hour meter 10.

  Here, it is assumed that the channel used for waiting for reception in the first communication network NT1 and the second communication network NT2 by the focused watt-hour meter 10 is the frequency F1. Further, it is assumed that the channel used by the upper power meter 10 to wait for reception in the first communication network NT1 and the second communication network NT2 is the frequency F2. In FIG. 2, the frequencies F1 and F2 at which the respective watt-hour meters 10 are waiting for reception are indicated by thick solid lines. In addition, when waiting for reception in the first communication network NT1 and the second communication network NT2, the terminal that has received the information always operates so as to return a response (reception response) to the transmission source terminal. Therefore, transmission of information is performed by pairing transmission and response.

  First, an operation when a request for the watt hour meter 10 is transmitted from the master unit 20 as in the case of remote meter reading or a power saving request will be described. In this case, the watt-hour meter 10 of interest receives a request on the channel having the frequency F1. When the watt hour meter 10 waits for reception and receives information including a request from the parent device 20, the watt hour meter 10 responds to the parent device 20.

  Here, the focused watt-hour meter 10 uses the frequency F1 for waiting for reception in the first communication network NT1, and the higher-order watt-hour meter 10 uses the frequency F2 for waiting for reception in the first communication network NT1. Therefore, the watt-hour meter 10 of interest can use the frequency F2 for the response. However, when this operation is performed, both watt-hour meters 10 need to switch the frequency used by the communication I / F unit 11 between a request time and a response time. For this reason, the frequency used for transmission and reception must be stabilized in a short time, and a high-performance communication I / F unit 11 is required, which may increase the cost of the watt-hour meter 10.

  Therefore, in this embodiment, the cost increase of the watt-hour meter 10 is suppressed by not changing the frequency used by both watt-hour meters 10 at the time of request and at the time of response. In other words, the watt-hour meter 10 that has received the request from the upper-side watt-hour meter 10 uses the same frequency as the period of waiting for reception as the response frequency. In addition, the upper watt-hour meter 10 that has transmitted a request to the watt-hour meter 10 of interest also waits for reception at the frequency at which the request is transmitted until a response is obtained.

  By the way, when the request | requirement from the main | base station 20 is a message | telegram request | requirement which transmits the usage-amount of electric power, the watt-hour meter 10 directs the message | telegram notification which uses the measured electric power usage to the main | base station 20 as a message. Send. When the request from the parent device 20 is to notify the device 30 like a demand response, the watt-hour meter 10 temporarily stores the request in the buffer, and then performs the second communication toward the device 30. Information is notified through the network NT2.

  As shown in FIG. 2, the response D12 to the message request D11 received from the upper power meter 10 is transmitted using the channel of the frequency F1 that has received the message request D11. On the other hand, the message notification D13 transmitted to the parent device 20 in response to the message request D11 is used by the upper power meter 10 to wait for reception in the first communication network NT1 after receiving the message request D11. It is transmitted using the channel of the frequency F2. The response D14 from the upper power meter 10 is returned using the channel of the frequency F2.

  In FIG. 2, the symbol (Rx) means that the target watt-hour meter 10 receives information, and the symbol (Tx) means that information is sent out from the watt-hour meter 10. These symbols are also used in the drawings described below. Information included in the message request and message notification is collectively referred to as message information.

  The transmission procedure among the watt-hour meter 10 of interest, the upper-side watt-hour meter 10 and the device 30 is as shown in FIG. In FIG. 3, the frequency selected for use in the transmission of information by the control unit 12 of the watt-hour meter 10 is shown in parentheses.

  The watt-hour meter 10 always waits for reception on the channel of the frequency F1 without distinguishing between the first communication network NT1 and the second communication network NT2. When the watt-hour meter 10 receives a telegram request from the parent device 20 via the higher-level watt-hour meter 10 in the reception waiting state (P1), the watt-hour meter 10 returns a response to the higher-level watt-hour meter 10 that is the transmission source. (P2). The upper watt-hour meter 10 has a limited time to wait for reception of a response, and when a response cannot be obtained within the limited time from the transmission of a request, it determines that a timeout has occurred and sets the frequency to be used. Revert.

  When the message request from the master device 20 is a message request that requires a message notification to be returned to the energy meter 10, such as a meter reading request for returning the energy amount from the energy meter 10, the control unit 12 A channel that can be received by the upper power meter 10 that is the transmission source of the request is selected (P3). Here, the channel that can be received by the transmission source is the channel of frequency F2. Therefore, the control unit 12 of the watt-hour meter 10 of interest notifies the transmission source of the message request of the content corresponding to the message request using the channel of the selected frequency F2 (P4). At this time, the response from the transmission source is returned using the channel of frequency F2 (P5). With such a series of operations, the watt-hour meter 10 can return a telegram notification having the content obtained by the telegram request to the master device 20 in response to the telegram request received from the master device 20.

  On the other hand, when the message request (P6) from the parent device 20 includes a request for the device 30 as a demand response, the watt-hour meter 10 sends a response from the parent device 20 to the device 30 after the response (P7). A telegram request is transmitted (P8). When receiving the message request from the watt hour meter 10, the device 30 returns a response to the watt hour meter 10 (P9).

  The communication between the watt hour meter 10 and the device 30 is not performed only when the watt hour meter 10 receives a request from the parent device 20, but between the watt hour meter 10 and the device 30. It is done regularly or irregularly. For example, when the power amount measured by the watt hour meter 10 is used in the device 30, the watt hour meter 10 periodically communicates with the device 30, or the watt hour meter 10 Delivery may be required. Such communication between the watt-hour meter 10 and the device 30 is performed during a period in which the watt-hour meter 10 is not performing communication on the first communication network NT1.

  In the configuration example described above, there is one type of channel used for communication in the first communication network NT1, but a control channel for transmitting control information and a telegram for transmitting telegram information such as power consumption are used. There may be two types of channels. The control information is used, for example, to notify a telegram channel. When two types of channels are used, the control unit 12 uses the communication I / F unit so that the frequency for waiting for reception in the control channel is the same as the frequency used for waiting for reception in the second communication network NT2. 11 is controlled.

  An operation example in the case of using a control channel and a telegram channel will be described below. In this operation example, the frequency F3 is used for the telegram channel.

  As shown in FIG. 4, the watt-hour meter 10 uses the channel of the frequency F1 for waiting for reception of the control channel in the first communication network NT1 and for waiting for reception in the second communication network NT2. The control information does not include a request from the parent device 20 and is used to notify the watt-hour meter 10 of information related to a telegram channel for transmitting telegram information and transmission start of telegram information. Therefore, the control information packet has a shorter bit length than the message information packet.

  The frequency used for the telegram channel in the first communication network NT1 is notified to the watt-hour meter 10 using the control information in the first communication network NT1. When the watt-hour meter 10 of interest receives the control information D15 while waiting for reception of the control channel, the watt-hour meter 10 returns a response D16 to the upper watt-hour meter 10. Further, the control unit 12 of the focused watt-hour meter 10 controls the communication I / F unit 11 to use the channel specified by the control information as a channel for receiving the telegram information from the first communication network NT1.

  Therefore, the watt-hour meter 10 of interest can receive the telegram request D17 transmitted using the channel specified by the higher-level watt-hour meter 10. In other words, the control information functions as a trigger for opening a telegram channel. In the example shown in FIG. 4, the frequency F3 is selected as the telegram channel. A response D18 to this request is returned on the channel of frequency F3.

  Here, when the message request D17 from the parent device 20 requests to transmit the message notification D21 to the higher-level watt-hour meter 10, the higher-level watt-hour meter 10 uses it as a control channel. The control information D19 is transmitted at the frequency F2. This control information D19 is used for notifying the higher-level watt-hour meter 10 of the frequency of the telegram channel and notifying the start of telegram transmission. When the focused watt-hour meter 10 transmits the control information D19 to the higher-order watt-hour meter 10, it receives a response D20 from the higher-order watt-hour meter 10.

  After the control information transmitted from the focused watt-hour meter 10 to the upper-side watt-hour meter 10 is transmitted, the focused watt-hour meter 10 transmits the frequency (here, the frequency F4) notified using the control information D19. ) Is used to transmit a telegram notification D21 to the upper watt-hour meter 10. Further, a response D22 is received from the watt-hour meter 10 on the upper side.

  In the configuration of the present embodiment, it is possible to realize reception waiting from two types of communication networks, the first communication network NT1 and the second communication network NT2, with one communication I / F unit 11. Note that whether the received signal is received from the first communication network NT1 or the second communication network NT2 is identified by the content of the frame.

(Embodiment 2)
In the first embodiment, the watt-hour meter 10 waits for reception of the first communication network NT1 and the second communication network NT2 through the same channel. On the other hand, in the present embodiment, different channels are used for reception waiting of the first communication network NT1 and the second communication network NT2. Furthermore, as shown in FIG. 5, in the present embodiment, the control unit 12 includes a period T21 during which a channel waiting for reception (first channel) of the first communication network NT1 is selected every predetermined time, The communication I / F unit 11 is controlled so as to include a period T22 during which a channel (second channel) waiting for reception of the second communication network NT2 is selected. In the illustrated example, the period T21 and the period T22 are alternately provided, and the period in which both the periods T21 and T22 are selected once is sufficiently shorter than the communication frame (for example, 1 millisecond or less). Degree).

  In the example shown in FIG. 5, the watt-hour meter 10 selects the channel of the frequency F1 during the reception waiting period T21 in the first communication network NT1, and the frequency during the reception waiting period T22 in the second communication network NT2. The F2 channel is selected. When the watt-hour meter 10 of interest receives a telegram request from the host-side watt-hour meter 10 or the parent device 20 through the channel of the frequency F1 during the period T21, the watt-hour meter 10 responds using the same frequency F1 as in the first embodiment. Do.

  In order to enable the above-mentioned operation, it is necessary to continue communication with a fixed frequency for the reception waiting period until the response is returned after receiving information during the reception waiting period. is there. This operation is unnecessary in the configuration of the first embodiment in which channels having the same frequency are used in the reception waiting period in the first communication network NT1 and the second communication network NT2.

  In order to enable the above-described operation, the control unit 12 waits for reception until it returns a response when it determines that it has received a predetermined signal for detecting the start of information reception during the reception wait period. The communication I / F unit 11 is controlled so as to maintain the frequency. Here, in order to determine the start of information reception, the control unit 12 determines that a predetermined signal has been received when any of the following conditions is satisfied.

  That is, the condition for determining that the predetermined signal has been received is, for example, when the received signal level is equal to or higher than a prescribed threshold, or when bit synchronization with the preamble included in the communication frame is established, the unique word included in the frame This is a case where frame synchronization is established by detection of.

  When the control unit 12 keeps communication at a frequency that is waiting for reception when the reception signal level becomes equal to or higher than the threshold, the frequency is maintained immediately after the frame is started. Even when they are alternately selected, the probability that a frame can be received increases. In addition, when establishing bit synchronization in the preamble or frame synchronization with a unique word, the control unit 12 receives a frame with a relatively high probability because a determination is made at the first part of the frame. Is possible.

  When a condition selected from these conditions is satisfied, the control unit 12 instructs the communication I / F unit 11 to maintain the same frequency until a response to the received information is returned.

  Note that when the reception signal level becomes equal to or greater than the threshold during the reception waiting period, the control unit 12 fixes the channel until the preamble, and when the bit synchronization can be achieved with the preamble, the time until the unique word A fixing operation may be performed. In this case, the control unit 12 uses three types of conditions one after another, and when frame synchronization is finally achieved, the channel is fixed until a response is returned, so that noise resistance is improved.

  In the following, it is assumed that two or more hops are required for communication with the parent device 20 and the focused watt-hour meter 10 communicates with the upper-side watt-hour meter 10. However, when the focused watt-hour meter 10 communicates with the parent device 20 in one hop, the operation is almost the same except that the parent device 20 does not communicate with the device 30.

  Here, the watt-hour meter 10 of interest uses the channel of the frequency F1 to wait for reception of the first communication network NT1, and the upper-side watt-hour meter 10 sets the channel of frequency F3 to wait for reception of the first communication network NT1. Assume that you are using it. The frequency F2 is used for waiting for reception of the second communication network NT2.

  When the watt-hour meter 10 of interest receives a telegram request from the higher-level watt-hour meter 10 in the channel of the frequency F1 in the period T21, the watt-hour meter 10 returns a response to the higher-level watt-hour meter 10 in the channel of the frequency F1.

  On the other hand, when a telegram notification is transmitted to the upper watt-hour meter 10 in response to the telegram request received by the focused watt-hour meter 10, the upper-side watt-hour meter 10 waits for reception on the first communication network NT1. The channel of the frequency F3 used in the above is selected.

  Referring to FIG. 5, the watt-hour meter 10 selects the frequency F1 for the reception waiting period T21 in the first communication network NT1, and in the reception waiting period T22 for the second communication network NT2. The frequency F2 is selected. Here, when the watt-hour meter 10 of interest receives the message request D31 from the first communication network NT1 in the period T21, the watt-hour meter 10 fixes the frequency and returns a response D32 to the higher-level watt-hour meter 10.

  Next, the watt-hour meter 10 of interest uses the frequency F3 waiting for reception of the message notification D33 to be returned to the message request D31 in the first communication network NT1 in the watt-hour meter 10 on the upper side. To the watt-hour meter 10 on the side. In addition, the watt-hour meter 10 of interest receives the response D34 from the higher-level watt-hour meter 10 using the channel of the same frequency F3.

  By the way, as in the first embodiment, two types of channels, a control channel and a telegram channel, may be used for the first communication network NT1. Hereinafter, in the watt-hour meter 10 of interest, the control channel reception waiting in the first communication network NT1 is the frequency F1, the message reception wait in the first communication network NT1 is the frequency F3, Assume that the reception waiting in the second communication network NT2 is the frequency F2. Further, it is assumed that in the watt-hour meter 10 on the upper side, the reception waiting for the control channel in the first communication network NT1 is the frequency F4 and the reception waiting for the telegram channel is the frequency F5.

  An example of operation under these conditions is shown in FIG. In the normal operation, the watt-hour meter 10 of interest switches between a period T21 for waiting for reception on the control channel of the frequency F1 and a period T22 for communicating with the device 30 on the channel of the frequency F2. The control unit 12 controls the communication I / F unit 11 so that the period T21 and the period T22 are included every predetermined time. In the illustrated example, the control unit 12 switches the frequency F1 and the frequency F2 alternately with a period (for example, about 1 millisecond or less) that is sufficiently shorter than the communication frame.

  As in the first embodiment, the control channel does not include the message request from the parent device 20, and transmits the control information D35 that notifies the wattmeter 10 of the information related to the message channel and the transmission start of the message request. Used for. A response D36 to the control information is returned using the same channel (frequency F1). When the communication I / F unit 11 receives the control information D35 in the reception waiting period T21 in the control channel of the frequency F1 used in the first communication network NT1, the control unit 12 of the watt-hour meter 10 of interest After returning the response D36, reception of the message request D37 from the upper watt-hour meter 10 is performed on the channel of the frequency F3 designated by the control information D35.

  Here, the watt-hour meter 10 of interest receives the telegram request D37 on the telegram channel (frequency F3), and returns a response D38 to the telegram request D37. Furthermore, the focused watt-hour meter 10 transmits the control information D39 to the higher-order watt-hour meter 10 at the frequency F4 used by the higher-order watt-hour meter 10 for the control channel. This control information D39 notifies that the watt-hour meter 10 of interest uses the frequency F5 for the telegram channel for transmitting the telegram notification D41, and indicates the start of transmission of telegram information. After this control information D39 is transmitted, the watt-hour meter 10 of interest transmits a telegram notification D41 corresponding to the telegram request D37 to the upper watt-hour meter 10. Responses D40 and D42 to control information D39 and message notification D41 are performed at frequencies F4 and F5, respectively. Other configurations and operations are the same as those of the first embodiment.

Claims (10)

Installed for each consumer, the function of measuring the amount of power used by the consumer, the function of communicating with the parent device through the first communication network, the equipment provided in the consumer and the second communication network A watt-hour meter with a function to communicate,
A radio signal using a radio wave as a transmission medium is transmitted and received, and a channel defined by the frequency of the radio signal can be selected from a plurality of types, and is shared in communication in the first communication network and communication in the second communication network A communication interface unit;
A watt hour meter comprising: a control unit that controls the communication interface unit so as to provide a communication period in the first communication network and a communication period in the second communication network. The control unit is configured to use the same channel for a first channel used for a reception waiting period in the first communication network and a second channel used for a reception waiting period in the second communication network. The watt-hour meter of Claim 1 which controls an interface part. The control unit controls the communication interface unit to notify the first communication network of information related to the first channel used during a reception waiting period in the first communication network. The watt hour meter described. The controller is
The communication interface unit is controlled so that the first channel is set to the same channel as the second channel when information on the second channel determined by the master is received through the communication interface unit. 2. The electricity meter according to 2. The controller is
The first channel used for the reception waiting period in the first communication network is different from the second channel used for the reception waiting period in the second communication network, and has a predetermined time shorter than the communication frame. The watt-hour meter according to claim 1, wherein the communication interface unit is controlled to include a period during which the first channel is selected and a period during which the second channel is selected. The controller is
6. When it is determined that a predetermined signal indicating the start of reception has been received during the reception waiting period, communication is continued using a channel that has received the predetermined signal among the first channel and the second channel. The watt hour meter described. The watt-hour meter according to claim 6, wherein the control unit determines that the predetermined signal is received when a received signal level is equal to or higher than a prescribed threshold value. The watt-hour meter according to claim 6, wherein the control unit determines that the predetermined signal is received when bit synchronization is established in a part of a preamble included in the frame. The watt-hour meter according to claim 6, wherein the control unit determines that the predetermined signal has been received when frame synchronization is established by detecting a unique word included in the frame. The watt-hour meter according to any one of claims 1 to 9,
A master unit communicating with the watt hour meter through the first communication network;
A power metering system comprising: a device provided in the consumer and communicating with the power meter through the second communication network.

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