Communication unit, time recovery method, and program

Abstract

To provide a communication unit that contributes to making it possible to restore a time of a clock function even when a long-time power failure occurs, without requiring a power source for backing up the clock function at power failure.SOLUTION: A communication unit is connected to a first power supply system and a network, and includes a control part and a time management part. The control part sets the order of priority of other communication units connected to a power supply system different from the first power supply system that are connected via the network after the first power supply system has been restored from a power failure. The control part receives current time information from the other communication units via the network according to the order of priority after the first power supply system has been restored from a power failure. The time management part recovers a time for clocking according to the current time information.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a communication unit, a time recovery method, and a program.

Background Art

[0002] Regarding a wireless communication system that performs wireless connection based on the priority of connection, the following documents can be cited.

[0003] Patent Document 1 relates to a wireless communication system in which, when a relay station receives a connection request from a wireless terminal, it determines the parent station candidate with the highest connection priority as the optimal parent station and performs a wireless connection to the optimal parent station.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] The following analysis is provided by the inventor of the present invention.

[0006] In a communication unit for an ad hoc network (for example, a smart meter for electricity and gas metering), it is equipped with a circuit for RTC (Real Time Clock) as a clock function. In order to continue the timekeeping by the clock function when the power supply that supplies power to such a communication unit fails, the power supply of the RTC circuit is backed up by an electric double layer capacitor so that, after the power failure is restored, the RTC circuit can continuously measure the current time.

[0007] In the backup of the power supply of the RTC circuit by the electric double layer capacitor, the backup time is limited by the capacitance of the electric double layer capacitor. When a long-term power outage occurs, the clock function cannot be maintained. As a result, after recovering from a long-term power outage, the time is initialized and the time cannot be restored.

[0008] In addition, by providing an electric double layer capacitor for backup, the cost of the communication unit increases, and the component mounting area on the printed circuit board in the communication unit increases. Therefore, there is a need for a time recovery method when the power outage is restored without using an electric double layer capacitor for backup of the power supply of the RTC circuit.

[0009] An object of the present invention is to provide a communication unit, a time recovery method, and a program that contribute to enabling the recovery of the time of the clock function even during a long-term power outage without the need for a power supply for backing up the clock function during a power outage.

Means for Solving the Problems

[0010] According to a first aspect of the present invention, it is connected to a first power supply system and a network, and includes a control unit and a time management unit. The control unit After the first power supply system recovers from a power outage, it sets the priority of other communication units connected to a power supply system different from the first power supply system and connected via the network. After the first power supply system recovers from a power outage, it receives current time information from the other communication units via the network according to the priority. The time management unit Performs recovery of the time for timing according to the current time information. A communication unit can be provided.

[0011] According to a second aspect of the present invention, a communication unit connected to a first power supply system and a network is After the first power supply system recovers from a power outage, set the priorities of other communication units that are connected to a power supply system different from the first power supply system and are connected via the network. After the first power supply system recovers from a power outage, receive time information from the other communication units via the network according to the priorities. Perform recovery of the time for timing according to the time information. A time recovery method can be provided. This method is associated with a specific machine, namely a computer that executes the above method.

[0012] According to a third aspect of the present invention, a program can be provided that causes a computer to execute a time recovery method.

[0013] These programs can be recorded on a computer-readable storage medium. The storage medium can be non-transitory such as a semiconductor memory, a hard disk, a magnetic recording medium, an optical recording medium, etc. The present invention can also be embodied as a computer program product.

Advantages of the Invention

[0014] According to the present invention, it is possible to provide a communication unit, a time recovery method, and a program that contribute to enabling recovery of the time of the clock function even after a long power outage without the need for a power supply to back up the clock function during a power outage.

Brief Description of the Drawings

[0015]

Figure 1

Figure 2

Figure 3

Figure 4

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Figure 8

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Figure 10

Mode for Carrying Out the Invention

[0016] In the present disclosure, the drawings may be associated with one or more embodiments. Also, each of the embodiments described below can be combined with other embodiments as appropriate, and the present invention is not limited by each embodiment.

[0017] First, an overview of one embodiment will be described with reference to the drawings. Note that the reference numerals in the drawings appended to this overview are for convenience of each element as an example to assist understanding, and are not intended to limit the present invention to the illustrated aspects. Also, the connection lines between blocks in the drawings and the like referred to in the following description include both bidirectional and unidirectional ones. The one-way arrow schematically shows the flow of the main signal (data) and does not exclude bidirectionality.

[0018] FIG. 1 is a block diagram showing an example of the configuration of a communication unit according to the present disclosure. Referring to FIG. 1, a communication unit 350 according to the present disclosure connected to a network 400 is shown. Other communication units 210 and 220 are also connected to the network 400. The communication unit 350 is connected to a first power supply system 390 and the network 400, and includes a control unit 11 and a time management unit 13. The control unit 11 sets the priorities of other communication units 210 and 220 that are connected to a power supply system 290 different from the first power supply system 390 and that are connected via the network 400 after the first power supply system 390 recovers from a power outage. Note that the first power supply system 390 and the power supply system 290 different from the first power supply system 390 may be AC power supplies. Also, each communication unit may be a smart meter for electricity and gas metering.

[0019] After the first power supply system 390 recovers from a power outage, the communication unit 350 receives time information from another communication unit 210 or 220 via the network 400 according to the priority. For example, when a higher priority is assigned to another communication unit 210 among other communication units 210 and 220 connected to the power supply system 290 different from the first power supply system 390, the current time information is received from the other communication unit 210 according to the priority.

[0020] Next, the communication unit 350 causes the time management unit 13 to recover the time at which the timekeeping is performed according to the current time information.

[0021] As described above, according to one embodiment, a communication unit, a time recovery method, and a program are provided that contribute to enabling the recovery of the time of the clock function even in the case of a long power outage without requiring a power supply for backing up the clock function during a power outage. Note that according to one embodiment, since a power supply for backing up the clock function during a power outage, for example, an electric double layer capacitor, is not required, the component mounting area of the communication unit can be reduced, and the communication unit can be miniaturized.

[0022] [First Embodiment] Next, the first embodiment will be described in detail with reference to the drawings. FIG. 2 is a block diagram showing an example of the configuration of a communication system according to the present disclosure. Referring to FIG. 2, the communication system 1000 includes a network 400, a concentrator 100 connected to the network 400, communication units 210, 220, 330, 340, 350, a collection server 600, and a second network 500 to which the concentrator 100 and the collection server 600 are connected. Each communication unit may be a smart meter for electricity and gas metering. The network 400 may be, for example, an ad hoc network. Hereinafter, it is also referred to as the ad hoc network 400.

[0023] Under each of the communication units 210, 220, 330, 340, 350, data collection devices 215, 225, 335, 345, 355 are respectively connected. Each of the communication units 210, 220, 330, 340, 350 converts the data from the data collection devices 215, 225, 335, 345, 355 into a wireless signal and transmits it to the concentrator 100 via the ad hoc network 400. The concentrator 100 sends the data to the collection server 600 via the second network 500, and the data is managed by the collection server 600.

[0024] Also, the communication units 210, 220 with the same power supply system are grouped into a group A200, and the communication units 330, 340, 350 with the same power supply system are grouped into a group B300. The power supply system of the group A200 is a different power supply system from that of the group B300. As an example, the power supply system of the group B300 may be the first power supply system 390 described with reference to FIG. 1, and the power supply system of the group A200 may be a different power supply system 290 from the first power supply system 390 described with reference to FIG. 1. Different power supply systems are assigned different power supply system IDs. The same power supply system ID-A is assigned to the communication units 210, 220 in the group A, and the same power supply system ID-B is assigned to the communication units 330, 340, 350 in the group B. It is assumed that it is possible to identify that the communication unit is connected to a different power supply system from the power supply system ID assigned to the communication unit.

[0025] FIG. 3 is a block diagram showing an example of the configuration of a conventional communication unit. The conventional communication unit 350C includes, as an example, four blocks: a control block 10C, a power supply block 20, a power failure detection block 30, and a wireless block 40.

[0026] The control block 10C includes a control unit 11C that controls the communication unit 350C, terminates external data 111 from a data collection device, and converts it into wireless data 113, a time management unit (hereinafter also referred to as RTC) 13 that controls the clock function, and an electric double layer capacitor 14 for backing up the RTC 13 during a power failure. The control unit 11C enables time management of the communication unit 350C based on the time data 112 from the RTC 13.

[0027] The wireless block 40 includes a wireless circuit 12 that converts the wireless data 113 from the control unit 11C into a wireless signal 700 and converts the wireless signal 700 into the wireless data 113.

[0028] The power supply block 20 includes an AC / DC conversion circuit 21 that converts an alternating current (AC) power supply, which may be a first power supply system 390 (hereinafter referred to as the AC power supply 390), into an internal power supply 212, and a power supply circuit 22 that converts the internal power supply 212 into a second internal power supply 221 for the RTC 13.

[0029] The power failure detection block 30 includes a power failure detection circuit 23 that detects that the AC power supply 390 has failed, and a capacitor 24 for backup during a power failure for backing up the power supply circuit 22 that generates the second internal power supply 221 in order to store the power failure time during a power failure.

[0030] Next, an example of the configuration of the communication unit according to the present disclosure will be described with reference to the drawings. FIG. 4 is a block diagram showing an example of the configuration of the communication unit according to the present disclosure. In the block diagram showing an example of the configuration of the communication system 1000 including the communication unit according to the present disclosure shown in FIG. 2, for example, the communication unit 350 is shown as an example. Other communication units 210, 220, 330, 340 may also have the same configuration as the communication unit 350 shown in FIG. 4. In FIG. 4, components with the same reference numerals as those in FIG. 3 indicate the same components. Hereinafter, the description will focus on the differences between the conventional communication unit 350C shown in FIG. 3 and the communication unit 350 according to the present disclosure shown in FIG. 4.

[0031] The control block 10 of the communication unit 350 according to the present disclosure shown in FIG. 4 includes a control unit 11 and a time management unit (RTC) 13, and does not include the backup electric double layer capacitor 14 for the RTC 13 included in the control block 10C of the conventional communication unit 350C shown in FIG. 3. Further, FIG. 5 is a block diagram showing an example of the configuration of the control unit 11 of the communication unit according to the present disclosure. Referring to FIG. 5, the control unit 11 of the control block 10 of the communication unit 350 according to the present disclosure includes an electric field strength and power supply system ID recording and updating unit 1101, a connection destination determination unit 1102, a power outage information reception and storage unit 1103, a power outage information and current time information transmission unit 1104, and a time correction unit 1105.

[0032] The electric field strength and power supply system ID recording and updating unit 1101 has a function of recording and updating the electric field strength and power supply system ID in a non-volatile memory (not shown). The connection destination determination unit 1102 has a function of determining the connection destination after power restoration from the electric field strength and power supply system ID recorded in the non-volatile memory. The power outage information reception and storage unit 1103 has a function of receiving and storing power outage information. The power outage information and current time information transmission unit 1104 has a function of transmitting power outage information and current time information to other communication units. Further, the time correction unit 1105 has a function of comparing the information before and after the power outage and correcting the time.

[0033] Next, the operation of the first embodiment will be described in detail with reference to the drawings. FIG. 6 is a sequence diagram showing an example of the operation of the communication unit according to the present disclosure. Referring to FIG. 6, a communication unit 350 belonging to group B300 to which a power supply system ID-B is assigned selects, confirms, stores, and then describes the operation until normal operation is performed on a communication unit 210 belonging to a different group A to which a different power supply system ID-A is assigned as the highest-priority communication destination after a power outage is restored.

[0034] In step S601, since the communication unit 350 is in an initialized state at the time of initial installation and operation, an installer registers the power supply system ID-B of group B, which groups communication units of the same power supply system, with respect to the communication unit 350. At the same time as registering the power supply system ID, the current time of the communication unit 350 is set, and then connection and communication are performed with other communication units 210 in step S602.

[0035] In step S602, in order to perform communication in the ad hoc network 400, the communication unit 350 connects and communicates with a plurality of other communication units 210 and 220, and extracts the power supply system ID-A of the other communication unit 210 from the wireless data 113 obtained from the received wireless signal 700. In addition, the field strength of the wireless signal 700 is measured and transmitted to the control unit 11 as data of the wireless data 113. Here, it is assumed that the field strength of the communication unit 210 is the strongest among the communication units of group A.

[0036] Next, in step S603, the field strength and power supply system ID recording update unit 1101 in the control unit 11 confirms and records the field strength and power supply system ID-A of the other communication units 210 and 220 thus obtained.

[0037] Also, in step S603, the connection destination determination unit 1102 of the control unit 11 assumes that the power supply system of the power supply system ID-B of group B has a power outage, selects the communication unit 210 having a different power supply system ID-A and the strongest field strength as the highest-priority communication destination after the power outage is restored.

[0038] Also, considering that the highest-priority communication destination cannot be connected and communicated with after recovery from a power outage, a different power system ID-A is used, and the electric field strength of, for example, communication unit 220, which is the second or lower in electric field strength, and the power system ID-A are also recorded, and are stored in a non-volatile memory (not shown) in control unit 11 so as not to be erased during and after a power outage. As an example, a table of communication units of communication destinations may be created and recorded in the table. Since the power system ID and the electric field strength may change, other communication units 210 and 220 of the communication destination are periodically connected and communicated with, and the table of the power system ID and the electric field strength is updated, thereby updating and recording the communication unit of the communication destination with the highest priority.

[0039] Also, in step S604, for other communication unit 210 as well, the electric field strength and power system ID recording update unit 1101 in the control unit 11 of other communication unit 210 records the electric field strength and power system ID-B of communication unit 350, and the connection destination determination unit 1102 of the control unit 11 of other communication unit 210 selects and records communication unit 350 as the communication unit with the highest priority after power outage recovery based on the electric field strength and power system ID-B of communication unit 350.

[0040] Next, in step S605, connection and communication are performed by ad hoc network 400. Through the communication in step S605, in steps S606 and S607, when the power outage is recovered, the communication destination with the highest priority, and in this case, communication unit 350 and communication unit 210, and communication unit 210 and communication unit 350, that is, communication unit 350 and communication unit 210 synchronize their times.

[0041] After that, in step S608, communication unit 350 transmits the data from data collection device 355 to collection server 600 via concentrator 100 and second network 500, and enters the normal operation state.

[0042] Note that the route in the ad-hoc network 400 through which the communication unit 350 transmits the data received from the data collection device 355 to the concentrator 100 and then to the collection server 600 via the second network 500 does not need to pass through the communication unit 210 with the highest priority after power restoration, i.e., the top-ranked destination. Also, for example, the data from the data collection device 215 is transmitted to the concentrator 100 via the communication unit 220 on the shortest route from the communication unit 210 to the concentrator 100, but it is the communication unit 350 that synchronizes the time.

[0043] FIG. 7 is a sequence diagram showing an example of the operation of the communication unit according to the present disclosure. FIG. 7 shows the operation of the communication unit 350 from the occurrence of a power outage when it is operating normally. The operation of the communication unit shown in FIG. 7 is assumed to show the operations of the communication unit 210 and the communication unit 350 described in FIG. 2, similar to those described in FIG. 6.

[0044] When a power outage occurs in the power supply system of group B300 to which the communication unit 350 belongs (step S701), in step S702, the communication unit 350 receives the power outage detection signal 231 from the power outage detection circuit 23. Using the power outage detection signal 231 as a trigger, based on the time data 112 from the RTC 13, the power outage information reception / storage unit 1103 in the control unit 11 confirms and stores the power outage time. Regarding the generation of the power outage detection signal 231 and the confirmation and storage of the power outage time from the occurrence of the power outage in step S701 to step S702, this will be described later with reference to FIG. 9.

[0045] Next, in step S703, the control unit 11 uses the power outage information and the current time information transmission unit 1104 in the control unit 11 to send a power outage notification including the power outage information and the time data 112 from the RTC 13 as the power outage time to the communication unit 210 of the communication destination with the highest priority after the power outage is restored. The communication unit 210 receives the power outage notification transmitted in step S704 in step S705. At this time, the communication unit 210 determines that the connection / communication from the communication unit 350 was disconnected due to a power outage in step S706, and stores the power outage notification including the power outage information and the power outage time transmitted from the communication unit 350 in step S707.

[0046] FIG. 8 is a sequence diagram showing an example of the operation of the communication unit according to the present disclosure. With reference to FIG. 8, the operation of the communication unit 350 from when it recovers from a power outage until it recovers the time and performs normal operation will be described. The operation of the communication unit shown in FIG. 8 is assumed to show the operations of the communication unit 210 and the communication unit 350 described in FIG. 2, similar to those described in FIG. 6.

[0047] After recovering from the power outage in step S801, the communication unit 350 connects and communicates with the communication unit 210 of the communication destination with the highest priority after the power outage based on the field strength / power supply system ID-A stored in step S802, and sends a power outage recovery notification to the communication unit 210 in step S803.

[0048] When the communication unit 210 receives the power outage recovery notification transmitted in step S804, the communication unit 210 that has received the power outage recovery notification sends the current time to the communication unit 350 that has recovered from the power outage in step S805.

[0049] The communication unit 350 that has recovered from the power outage and received the current time transmitted from the communication unit 210 in step S806 adjusts and restores the time from the received current time in step S807.

[0050] After that, the communication unit 350 enters the normal operation state in step S811.

[0051] Next, regarding the generation of the power failure detection signal 231 and the confirmation and storage of the power failure time from the occurrence of the power failure in step S701 of FIG. 7, it will be described with reference to FIG. 9. FIG. 9 is a timing diagram showing an example of the operation of the communication unit according to the present disclosure. FIG. 9 shows (a) the voltage value of the AC power supply 390 supplied to the communication unit 350 according to the present disclosure shown in FIG. 4, (b) the voltage value of the internal power supply 212, (c) the voltage value of the second internal power supply 221, and (d) the power failure detection signal 231 output by the power failure detection circuit 23. T1, T2, and T3 indicate each time point, T indicates the backup time, and Vth is the power failure detection threshold voltage.

[0052] When the AC power supply 390 fails at time point T1, the voltage value of the (b) internal power supply 212 converted by the AC / DC conversion circuit 21 is backed up by the capacitor 24 for backup during power failure, but gradually decreases. The voltage value of the (b) internal power supply 212 reaches the power failure detection threshold voltage Vth at time point T2 and then becomes zero.

[0053] At the same time, the power supply circuit 22 is also backed up, and the voltage value of the (c) second internal power supply 221 can be maintained until time point T3. After that, the voltage value of the (c) second internal power supply 221 becomes zero.

[0054] On the other hand, when the (b) internal power supply 212 reaches the set power failure detection threshold voltage Vth at time point T2, the power failure detection circuit 23 activates the power failure detection signal 231 for the control unit 11. In the present disclosure, as an example, the (d) power failure detection signal 231 is active at the Low level.

[0055] When the control unit 11 detects that the power failure detection signal 231 has become active, it determines that a power failure has occurred. During the backup time T (from time point T2 to time point T3) during which the control unit 11 can operate by the (c) second internal power supply 221 output by the power supply circuit 22, which is backed up by the capacitor 24 for backup during power failure and maintained until time point T3, the control unit 11 transmits a power failure notice including the power failure information and the time data 112 from the RTC 13 as the power failure time to the communication unit 210 of the communication destination with the highest priority after the power failure is restored, and records the time data 112 from the RTC 13 as the power failure time. Further, the time data is stored in a non-volatile memory, for example, in the control unit 11 so as not to be erased even during and after a power failure.

[0056] At the timing as described above, when a power failure occurs in step S701 of FIG. 7, the generation of the power failure detection signal 231 in step S702 and the power failure time can be confirmed and stored.

[0057] As described above, according to the first embodiment, it is possible to provide a communication unit, a time recovery method, and a program that contribute to enabling the recovery of the time of the clock function even in the case of a long-term power failure without requiring a power source for backing up the clock function during a power failure.

[0058] [Second Embodiment] Next, the second embodiment will be described in detail. In the first embodiment, the power supply system is identified using the power supply system ID, but the power supply system ID may be changed to area information created from a map where the communication unit held by the operator is installed. Further, the communication unit of the communication destination with the highest priority after a power failure may be selected as the communication unit with different area information having the strongest electric field intensity. For example, the area information may be divided into n squares on the map and one of them may be used to indicate it.

[0059] As described above, according to the second embodiment, similar to the first embodiment, it is possible to provide a communication unit, a time recovery method, and a program that contribute to enabling the recovery of the time of the clock function even in the event of a long-term power outage without the need for a power source to back up the clock function during a power outage.

[0060] As described above, each embodiment of the present invention has been described. However, the present invention is not limited to the above-described embodiments, and further modifications, substitutions, and adjustments can be made without departing from the basic technical idea of the present invention. For example, the network configuration shown in each drawing, the configuration of each element, and the expression form of the message are examples for assisting the understanding of the present invention, and are not limited to the configurations shown in these drawings. Also, "A and / or B" is used to mean at least either A or B.

[0061] Also, the procedures shown in the first to second embodiments described above can be realized by a program that causes a computer (9000 in FIG. 10) that functions as a communication unit or a control unit of the communication unit according to the present invention to realize the functions of the communication unit or the control unit of the communication unit. Such a computer is exemplified by a configuration including a CPU (Central Processing Unit) 9010, a communication interface 9020, a memory 9030, and an auxiliary storage device 9040 in FIG. 10. That is, the CPU 9010 in FIG. 10 may execute the control program of the communication unit or the control unit of the communication unit and perform the update process of each calculation parameter held in the auxiliary storage device 9040 or the like.

[0062] The memory 9030 is a RAM (Random Access Memory), a ROM (Read Only Memory), or the like.

[0063] That is, each part (processing means, function) of the communication unit or the control unit of the communication unit shown in the first to second embodiments described above can be realized by a computer program that causes the processor of the above computer to execute the above-described respective processes using its hardware.

[0064] Finally, the preferred embodiments of the present invention will be summarized. [First Embodiment] The communication unit is connected to the first power supply system and the network, and may include a control unit and a time management unit. After the first power supply system recovers from a power outage, the control unit of the communication unit may set the priority of another communication unit that is connected to a power supply system different from the first power supply system and is connected via the network. After the first power supply system recovers from a power outage, the control unit of the communication unit may receive current time information from the other communication unit via the network according to the priority. The time management unit of the communication unit may restore the time for timing according to the current time information. [Second Embodiment] For the communication unit according to the first embodiment, the control unit After the start of the power outage of the first power supply system, it is preferable to send a power outage notice to the other communication unit, and after the first power supply system recovers from the power outage, to receive the current time information from the other communication unit that sent the power outage notice. [Third Embodiment] For the communication unit according to the first or second embodiment, it is preferable that the priority is set according to the strength of the electric field intensity of the other communication unit. [Fourth Embodiment] For the communication unit according to the third embodiment, it is preferable that the network is an ad hoc network. [Fifth Embodiment] For the communication unit according to the fourth embodiment, it is preferable that the communication unit and the other communication unit are smart meters. [Sixth Embodiment] In the time recovery method, a communication unit connected to the first power supply system and the network may set the priority of another communication unit that is connected to a power supply system different from the first power supply system and is connected via the network after the first power supply system recovers from a power outage. The time recovery method may be such that after the first power supply system recovers from a power outage, the communication unit receives current time information from the other communication units via the network according to the priority. The time recovery method may be such that the communication unit recovers the time for timing according to the current time information. [Seventh Embodiment] In the time recovery method according to the sixth embodiment, after the start of the power outage of the first power supply system, a power outage notification is sent to the other communication units, and after the first power supply system recovers from the power outage, it is preferable to receive the current time information from the other communication unit that sent the power outage notification. [Eighth Embodiment] In the time recovery method according to the sixth or seventh embodiment, it is preferable that the priority is set according to the strength of the electric field intensity of the other communication units. [Ninth Embodiment] A program for causing a computer to execute the time recovery method according to the sixth or seventh embodiment. [Tenth Embodiment] A program for causing a computer to execute the time recovery method according to the eighth embodiment. Note that, similar to the first embodiment, the sixth and ninth embodiments can be expanded to the fourth to fifth embodiments.

[0065] Note that the disclosure of Patent Document 1 is incorporated herein by reference. Within the scope of the entire disclosure of the present invention (including the claims), modifications and adjustments of the embodiments or examples can be made based on the basic technical idea. Also, within the scope of the disclosure of the present invention, various combinations or selections of various disclosure elements (including each element of each claim, each element of each embodiment or example, each element of each drawing, etc.) are possible. That is, the present invention naturally includes all the disclosures including the claims, and various deformations and corrections that a person skilled in the art could make according to the technical idea. In particular, regarding the numerical ranges described in this document, any numerical value or small range included within the range should be construed as specifically described even without separate description. Furthermore, each disclosure item of the above-cited document is, if necessary, construed as being included in the disclosure of the present application as part of the disclosure of the present invention, and can be used in combination with the description items of this document, in part or in whole, in accordance with the gist of the present invention.

Explanation of Reference Signs

[0066] 10, 10C Control Block 11, 11C Control Unit 12 Wireless Circuit 13 Time Management Unit (RTC) 14 Backup Electric Double-Layer Capacitor 20 Power Block 21 AC / DC Conversion Circuit 22 Power Supply Circuit 23 Power Failure Detection Circuit 24 Power Failure Backup Capacitor 30 Power Failure Detection Block 40 Wireless Block 100 Concentrator 111 External Data 112 Time Data 113 Wireless Data 200 Group A 210, 220, 330, 340, 350, 350C Communication Unit 212 Internal Power Supply 221 Second Internal Power Supply 231 Power failure detection signal 215, 225, 335, 345, 355 Data collection devices 290 Power supply system different from the first power supply system 390 First power supply system 300 Group B 400 Ad hoc network 500 Second network 600 Collection server 700 Wireless signal 1000 Communication system 1101 Recording and updating unit for electric field strength and power supply system ID 1102 Connection destination determination unit 1103 Power failure information reception and storage unit 1104 Power failure information and current time information transmission unit 1105 Time correction unit 9000 Computer 9010 CPU 9020 Communication interface 9030 Memory 9040 Auxiliary storage device

Claims

1. A communication unit connected to a first power supply system and a network, including a control unit and a time management unit, wherein the control unit sets the priority of other communication units connected to a power supply system different from the first power supply system, which is connected via the network, after the first power supply system recovers from a power outage; receives current time information from the other communication units via the network according to the priority after the first power supply system recovers from a power outage; wherein the time management unit performs recovery of the time for timing according to the current time information; communication unit.

2. The control unit sends a power outage notice to the other communication units after the start of the power outage of the first power supply system; receives the current time information from the other communication units that sent the power outage notice after the first power supply system recovers from the power outage; The communication unit according to claim 1.

3. The communication unit according to claim 1 or 2, wherein the priority is set according to the strength of the electric field intensity of the other communication units.

4. The communication unit according to claim 3, wherein the network is an ad hoc network.

5. The communication unit according to claim 4, wherein the communication unit and the other communication units are smart meters.

6. A communication unit connected to a first power supply system and a network wherein, after the first power supply system recovers from a power outage, it sets the priority of other communication units connected to a power supply system different from the first power supply system, which is connected via the network; after the first power supply system recovers from a power outage, it receives current time information from the other communication units via the network according to the priority; performs recovery of the time for timing according to the current time information; time recovery method.

7. After the start of the power outage of the first power supply system, it sends a power outage notice to the other communication units; after the first power supply system recovers from the power outage, it receives the current time information from the other communication units that sent the power outage notice; The time recovery method according to claim 6.

8. The time recovery method according to claim 6 or 7, wherein the priority is set according to the strength of the electric field intensity of the other communication units.

9. A program for causing a computer to execute the time recovery method according to claim 6 or 7.

10. ​ A program for causing a computer to execute the time restoration method according to claim 8.

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