WO2014013667A1

WO2014013667A1 - Meter reading device

Info

Publication number: WO2014013667A1
Application number: PCT/JP2013/003575
Authority: WO
Inventors: 崇士渡邊; 山本　雅弘
Original assignee: パナソニック株式会社
Priority date: 2012-07-19
Filing date: 2013-06-06
Publication date: 2014-01-23
Also published as: JPWO2014013667A1; CN104396274A; CN104396274B; JP6161006B2

Abstract

A synchronous communication system including server devices, at least one relay device, and a plurality of client devices respectively associated with any of a plurality of meters and respectively subordinate to any of the server devices and relay devices is utilized. Each of the plurality of client devices has: a beacon reception unit (23) for receiving a beacon signal periodically transmitted by a device to which the client device is subordinate, from among the server devices and relay devices; and a call wait control unit (25) for calculating a wait time of a duration from the time at which a meter reading event occurs until a meter reading value notification is made, doing so according to the beacon signal interval, and the number of stages of relay devices between the device itself and the client device, and for controlling the timing of calls according to the calculated wait time.

Description

Meter reading device

The present invention relates to a meter-reading device that collects meter-reading value information from a plurality of meters that measure usage amounts of electricity, gas, water, and the like.

According to the technique of Patent Document 1, when a communication collision occurs when a plurality of meters with communication functions connected on the same communication line make a call at the same time, the re-call timings of the meters are shifted from each other. The centralized meter-reading apparatus sets a re-calling time for each meter, thereby preventing communication collision in re-calling.

The technology of Patent Document 2 efficiently collects meter reading value information without causing congestion on the telephone line due to simultaneous calls from a plurality of meter reading terminal devices even when wireless calling is performed simultaneously from the meter reading central device. The purpose is to do. Therefore, the value of the transmission time interval and the range of the user ID of the meter reading terminal device to be called are included in the message at the time of simultaneous calling from the meter reading central device, and each meter reading terminal device has a plurality of called meter reading terminals. The terminal device recognizes from the user ID of its own device the number of times the own device should start transmission, calculates the wait time from the simultaneous call time based on the value of the transmission time interval, and this wait time Start sending when it has passed. Thereby, in response to the simultaneous call from the meter-reading central device, the plurality of called meter-reading terminal devices sequentially transmit the meter-reading value information at different times.

On the other hand, there is known a synchronous wireless communication system in which a parent device periodically transmits a beacon signal and a child device periodically receives the beacon signal. Since the slave unit sets its own clock to the master unit clock and waits for reception of polling data from the master unit at a predetermined timing, it is particularly effective for power saving in a battery-powered slave unit. In such a synchronous radio communication system, when direct communication is not possible between a master unit and a slave unit, a relay unit that relays and transmits a radio signal is used.

JP 2008-258715 A JP 2001-86574 A

The technique of Patent Document 1 described above is to prevent a collision in re-calling, and cannot prevent the collision at the first transmission. In addition, since the centralized meter-reading device needs to set a recall time for each meter, it is difficult to flexibly respond to changes in the network configuration.

Moreover, since the technique of the said patent document 2 set the transmission time interval to each meter-reading terminal device by the meter-reading central device, the burden of the meter-reading central device was large. Further, the technique is not suitable for a meter reading device using a synchronous communication system including a repeater.

An object of the present invention is to provide a meter reading device that efficiently and automatically collects meter reading value information from a plurality of meters using a synchronous communication system including a repeater.

In order to achieve the above object, the present invention relates to a meter-reading device that collects meter-reading value information from a plurality of meters, each of which is associated with a master unit, at least one relay device, and each of the plurality of meters. In a synchronous communication system including a plurality of slave units subordinate to either the master unit or the relay unit, the master unit sequentially receives notification of meter reading value information from each of the plurality of slave units. As described above, in consideration of the relay delay between the plurality of slave units and the master unit, each of the plurality of slave units is periodically started from a subordinate destination of the slave unit among the master unit and the relay unit. A beacon receiving unit that receives a beacon signal that is transmitted automatically, a wait time from when a meter-reading event occurs to when a meter-reading value is notified, the interval between the beacon signals, and between the own device and the parent device Depending on the number of stages of the repeater Out, and in which it was decided to have a call wait control unit for controlling the timing of the call according to the wait time the calculated.

It is preferable that the information indicating the number of stages of the repeater is included in the beacon signal received by the slave unit.

Further, it is preferable that each of the plurality of slave units further calculates the wait time using its own identification number.

According to the present invention, it is possible to efficiently and automatically process calls such as periodic meter reading.

It is a hierarchical structure figure of the radio | wireless communications system utilized with the meter-reading apparatus of the gas meter which concerns on embodiment of this invention. It is a figure which shows the slot positional relationship between the apparatuses in the radio | wireless communications system of FIG. (A) is a figure which shows the structure of a basic slot, (b) is a figure which shows the structure of the link connection slot in a basic slot, respectively. (A) is a figure which shows the structure of a link connection signal, (b) is a figure which respectively shows the structure of the repetition frame in a link connection signal, or the frame structure of a beacon signal. It is a figure which shows the internal structure of each apparatus in the radio | wireless communications system of FIG. 1, Comprising: (a) is a main | base station, (b) is a relay machine, (c) is a block diagram which respectively shows a subunit | mobile_unit. It is a flowchart which shows the initial setting operation | movement of the subunit | mobile_unit shown by FIG.5 (c). It is a flowchart which shows the meter-reading operation | movement of the subunit | mobile_unit shown by FIG.5 (c). It is a figure which shows the order of the meter-reading value notification operation | movement of each subunit | mobile_unit in the radio | wireless communications system of FIG. FIG. 2 is a timing diagram in the case of 1-channel transmission in the wireless communication system of FIG. 1. FIG. 2 is a timing diagram in the case of 2-channel transmission in the wireless communication system of FIG. 1.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. In addition, this invention is not limited by this embodiment.

FIG. 1 is a hierarchical structure diagram of a wireless communication system used in a meter reading device of a gas meter according to an embodiment of the present invention. In the wireless communication system of FIG. 1, one master unit, ten relay units, and 330 slave units constitute a tree-shaped network. Each of the slave units is attached to or built in the gas meter. That is, the wireless communication system of FIG. 1 constitutes a meter-reading device that collects meter-reading value information from, for example, a slave unit of a gas meter arranged in each of 330 units in one apartment house. The master unit transmits the collected meter reading value information to a data center (not shown) via a telephone line or the like.

1 will be described in more detail. First, 30 slave units having identification numbers 000 to 029 are arranged so as to be subordinate to the master unit. These child devices having identification numbers 000 to 029 communicate directly with the parent device without using a relay device. Thirty slave units having identification numbers 100 to 129 are arranged so as to be subordinate to the relay unit having identification number 10. The slave units having the identification numbers 100 to 129 communicate with the master unit via one relay unit having the identification number 10. Thirty slave units having identification numbers 200 to 229 are arranged so as to be subordinate to the relay unit having identification number 20. The slave units having the identification numbers 200 to 229 communicate with the master unit via two relay units having the identification numbers 20 and 10, respectively. Thirty slave units having identification numbers 300 to 329 are arranged so as to be subordinate to the relay unit having identification number 30. The slave units having the identification numbers 300 to 329 communicate with the master unit via three relay units having the identification numbers 30, 20, and 10, respectively. Although description in the middle is omitted, 30 slave units having identification numbers A00 to A29 are arranged to be subordinate to the relay unit having the identification number A0. The slave units having the identification numbers A00 to A29 communicate with the master unit via 10 relay units having the identification numbers A0, 90, 80, 70, 60, 50, 40, 30, 20, and 10, respectively.

In the following description, when m = 0, 1, 2, 3,..., 10, when the slave unit is connected to the master unit via m relay units, it is expressed that the number of relay stages is m. . Also, the identification number of the relay device may be referred to as a relay device ID, and the identification number of the slave device may be referred to as a slave device ID.

A clock signal called a beacon signal is periodically transmitted from the master unit. The slave units ID000 to 029 and the relay unit ID10 directly connected to the master unit periodically capture the beacon signal from the master unit and synchronize with the clock of the master unit. Here, the parent device is defined as the upper device, and the child devices with ID000 to 029 and the relay device with ID10 directly connected to the parent device that is the upper device are defined as the lower devices.

Similarly, for the slave units with IDs 100 to 129, the relay unit with ID 10 works as the master unit. That is, the ID10 repeater periodically transmits a beacon signal for clock adjustment. The ID100 to 129 slave units and ID20 relay units directly connected to the ID10 relay unit periodically capture the beacon signal from the ID10 relay unit and synchronize with the clock of the ID10 relay unit. The upper device is an ID10 relay device, and the lower device is an ID100 to 129 slave device and an ID20 relay device directly connected to the ID10 relay device.

FIG. 2 is a diagram showing a slot position relationship between devices in the wireless communication system of FIG. FIG. 3A shows the configuration of the basic slot, and FIG. 3B shows the configuration of the link connection slot in the basic slot. Before describing FIG. 2 in detail, the configuration of the slots managed by each device will be described with reference to FIGS. 3 (a) and 3 (b).

As shown in FIG. 3A, the basic slot is composed of T1 [seconds], and this basic slot is repeated on the time axis. The basic slot is further composed of a lower slot and an upper slot. The lower slot length and the upper slot length are each half the time of T1. The lower slot is a slot for communicating with the lower apparatus, and the upper slot is a slot for communicating with the upper apparatus. The lower slot is divided into a beacon transmission slot (BT) 31, a link connection slot (L) 32, and a data communication slot (D) 33. The upper slot is divided into a beacon receiving slot (BR) 34, a link connecting slot (L) 35, and a data communication slot (D) 36. The host device periodically transmits a beacon signal using a beacon transmission slot (BT) 31. The lower device periodically receives a beacon signal from the upper device in a beacon receiving slot (BR) 34. The link connection slots (L) 32 and 35 are slots for communication between the upper device and the lower device for link connection. The data communication slots (D) 33 and 36 are slots for performing communication for exchanging data after the link connection between the upper device and the lower device.

As shown in FIG. 3B, the link connection slots (L) 32 and 35 are composed of a lower call slot 37 and an upper response / upper call slot 38. The lower call slot 37 is a slot for the lower device to transmit a link connection request signal when it is desired to establish a link connection from the lower device. The upper response / upper call slot 38 is a slot for the upper device to return a response to the link connection request signal from the lower device, or when the upper device wishes to perform link connection from the upper device, the upper device transmits the link connection request signal. Is a slot for transmitting. T2 is the slot length of the lower call slot 37, and T3 is the slot length of the higher response / upper call slot 38.

Next, FIG. 2 will be described. FIG. 2 shows the slot position relationship among the parent device, the relay devices with IDs 10, 20, and 30 and the child devices with IDs 200, 201, and 300. In the slot configuration of FIG. 2, the notation “lower” represents the lower slot of FIG. Similarly, the notation “upper” represents the upper slot in FIG. Then, slot numbers 1 to 256 are assigned to the basic slots in order, and the slot number 256 is followed by the slot number 1. The upper part of the slot configuration shown in FIG. 2 is the slot number. In FIG. 2, signals indicated by arrows such as B1 to B4 indicate beacon signals, and signals indicated by arrows C1 to C6 indicate signals for entry.

In the example of FIG. 2, the beacon signal is transmitted from the beacon transmission slot 31 in the lower slot of every other basic slot. The beacon signal transmitted from the parent device is periodically received by the relay device with ID10. The repeater with ID10 is configured to receive the beacon signal B1 transmitted from the slot number 1 of the master unit. The beacon signal B1 transmitted from the slot number 1 includes information on the beacon number 1. When the beacon signal B1 with the beacon number 1 is received by the repeater ID10, the start position of the lower slot of the basic slot number 1 of the master unit becomes the start position of the upper slot of the basic slot number 255 of the repeater ID10. Reconfigure the slots. And the repeater of ID10 transmits a beacon signal at the odd-numbered basic slot number, like the master unit. Thereafter, the lower device receives the beacon signal transmitted from the basic slot number 1 of the upper device by the same operation, and reconfigures its own slot in synchronization with the timing of the upper device.

Next, the operation when the ID200 slave enters the wireless communication system will be described. The slave unit with ID 200 performs a beacon signal reception operation in a continuous reception state for a period longer than the beacon transmission interval T5. This operation is called a search mode as shown in FIG. During the search mode period, the master unit and the repeaters with IDs 10, 20, and 30 always transmit a beacon signal at least once. For example, when the slave unit of ID200 recognizes that the beacon signal B3 from the relay unit of ID20 is equal to or higher than a predetermined level, the slave unit of ID20 subordinates to the relay unit of ID20, and therefore enters the entry request signal C1 in the upper slot of slot number 253. It transmits to the relay machine of ID20. Upon receiving the entry request signal C1, the ID20 relay device transmits a signal C2 that relays the entry request signal from the ID200 slave device to the ID10 relay device. Further, the repeater with ID10 transmits a signal C3 for relaying the entry request signal to the parent device. When receiving the signal C3, the parent device transmits an entry permission signal to the ID 200 child device via the relay signals C4, C5, and C6. Through the operation described above, the slave unit with ID 200 is subordinated under the relay unit with ID 20.

C1 to C6 representing the entry request signal, the entry permission signal, and the relay signal use the

data communication slots

33 and 36 after performing link connection using the

link connection slots

32 and 35 shown in FIG. Sent and received.

FIG. 4A shows the signal format of the link connection signal transmitted / received in the

link connection slots

32 and 35. The link connection signal is composed of n (n is an integer) repetitive frames 51 to 56 and a main body frame 57. FIG. 4B shows the structure of the repeated frame. The repetitive frame includes a bit synchronization signal 58 for determining a bit sampling position, a frame synchronization signal 59 for detecting the head of data included in the frame, a control signal 60 carrying various control information, It consists of a simple ID 61 in which the ID for identification is shortened. The ID is, for example, 64 bits, and the simple ID is 16 bits obtained by dividing the ID into four. The information indicating which 16 bits of the ID divided into four are used as the simple ID 61 is in the control signal 60. The repetitive frame length is T6. Therefore, n repetitive frame lengths T7 satisfy T7 = n × T6. Repetitive frames 51 to 56 are given repetitive frame numbers 1 to n, and the repetitive frame number is added to the control signal 60. The repeat frame is transmitted from a repeat frame having a large repeat number as shown in FIG. 4A, and the repeat frame number is decremented one by one, and the repeat frame number immediately before the main body frame 57 is 1.

The signal format of the beacon signal is the same as the repetitive frame configuration shown in FIG. 4B, and the relay stage number information is on the control signal 60. The simple ID 61 is replaced with a beacon ID in the case of a beacon signal. The repeater and the master that are transmitting the beacon signal can be identified by the beacon ID, and at the same time, the number of relay stages can be easily recognized by the slave. More specifically, the base unit has information indicating that the number of relay stages is 0, the ID 10 relay apparatus has information indicating that the number of relay stages is 1, and the ID 20 relay apparatus has 2 relay stages. Is put on the beacon signal transmitted by each.

FIG. 5 (a) to FIG. 5 (c) show the internal configuration of each layer of the wireless communication apparatus in the wireless communication system of FIG. FIG. 5 (a) is a block diagram showing a master unit, FIG. 5 (b) is a relay unit, and FIG. 5 (c) is a block diagram showing a slave unit.

First, an outline of the configuration of the parent device will be described with reference to FIG. 1 is an antenna, 2 is a transmission / reception unit, 3 is a beacon transmission unit, 4 is a link connection unit, and 5 is a control unit. The control unit 5 performs time management of the entire wireless communication device and control of each unit. The transmission / reception unit 2 includes a wireless transmission / reception circuit for performing wireless communication via the antenna 1.

Next, an outline of the configuration of the repeater will be described with reference to FIG. 11 is an antenna, 12 is a transmission / reception unit, 13 is a beacon transmission unit, 14 is a beacon reception unit, 15 is a link connection unit, and 16 is a control unit. The control unit 16 performs time management of the entire wireless communication device and control of each unit. The transmission / reception unit 12 includes a wireless transmission / reception circuit for performing wireless communication via the antenna 11.

Next, an outline of the configuration of the slave unit will be described with reference to FIG. Reference numeral 21 denotes an antenna, 22 denotes a transmission / reception unit, 23 denotes a beacon reception unit, 24 denotes a link connection unit, 25 denotes a call weight control unit, 26 denotes a control unit, and 27 denotes a storage unit. The control unit 26 performs time management of the entire wireless communication device and control of each unit. The transmission / reception unit 22 includes a wireless transmission / reception circuit for performing wireless communication via the antenna 21.

The beacon transmission in the beacon transmission slot 31 in FIG. 3 (a) is performed using the

beacon transmission units

3 and 13 in FIG. 5 (a) and FIG. 5 (b). Beacon reception in the beacon reception slot 34 in FIG. 3A is performed using the

beacon receiving units

14 and 23 in FIGS. 5B and 5C. Further, the link connection communication in the

link connection slots

32 and 35 in FIG. 3A is performed using the

link connection portions

4, 15 and 24 in FIGS. 5A to 5C.

The call waiting control unit 25 of the slave unit in FIG. 5 (c) determines the wait time from when the meter reading event occurs until the meter reading value is notified, between the interval between the beacon signals and the own unit and the master unit. Calculation is made according to the number of repeater stages and the ID of the own machine, and the call timing is controlled according to the calculated wait time. Since the slaves collide when calling out the meter reading value notification all at once, a call waiting time is added to delay the notification timing. The storage unit 27 stores the wait time calculated by the call waiting control unit 25.

FIG. 6 is a flowchart showing the initial setting operation of the slave shown in FIG. In step S01, the network is entered using the procedure described with reference to FIG. In step S02, a periodic meter reading setting is received from the master unit. For example, the meter reading time can be set as what hour and minute every day of the month. Daily, weekly, or monthly time settings are also possible. In step S03, the relay stage number information is acquired from the beacon signal. In step S04, the wait time of the own device is calculated and stored. When the beacon signal interval is BI [seconds], the wait time [seconds] is
Wait time = BI x (number of relay stages x 30 + lower 2 digits of slave unit ID)
Is calculated by The beacon interval BI is 12.8 seconds, for example.

FIG. 7 is a flowchart showing the meter reading operation of the slave shown in FIG. 5 (c). In step S11, it is checked whether a meter reading event has occurred, that is, whether the set meter reading time has come. If the meter reading time has not yet arrived, it waits until that time. When the meter reading time comes, the process proceeds to step S12. In step S12, a call waiting state is entered according to the calculated wait time. When the wait time has elapsed, the process proceeds to step S13. In step S13, after the initial transmission of the meter reading value notification is executed, the process proceeds to step S14. In step S14, the presence or absence of an acknowledge (ACK) signal from the parent device is checked. If the ACK signal is received, it is determined that the meter reading value notification has been received by the master unit, and the process returns to step S11. If the ACK signal is not received, it is determined that the meter reading value notification has not been received by the master unit, and the process proceeds to step S15. In step S15, a call waiting state before the first retransmission is entered. When the predetermined wait time has elapsed, the process proceeds to step S16. In step S16, after executing the first retransmission of the meter reading value notification, the process proceeds to step S17. In step S17, the presence / absence of an ACK signal from the parent device is checked. If the ACK signal is received, it is determined that the meter reading value notification has been received by the master unit, and the process returns to step S11. If the ACK signal is not received, it is determined that the meter reading value notification has not been received by the master unit, and the process proceeds to the next step. Then, after executing the 20th retransmission of the meter reading notification in step S18, the process proceeds to step S19. In step S19, the presence or absence of an ACK signal from the parent device is checked. If the ACK signal is received, it is determined that the meter reading value notification has been received by the master unit, and the process returns to step S11. If the ACK signal is not received, it is determined that the meter reading value notification has not been received by the master unit, and the process proceeds to step S20. In step S20, a retransmission error is stored.

FIG. 8 shows the order of the meter reading value notification operation of each slave unit in the wireless communication system of FIG. In this example, it is assumed that the meter reading time 0:00 (0: 0) is set from the master unit. When the time reaches 0:00, the 330 slave units simultaneously determine the meter reading value information. However, the call waiting time differs for each slave unit.

Since the slave unit of ID000, which is directly subordinate to the master unit, determines that the wait time of its own unit is 0 seconds from the number of relay stages = 0 and the lower two digits of ID = 0, it immediately issues a meter reading value notification to the master unit. Call. Similarly, the slave unit of ID001 directly subordinate to the master unit has the number of relay stages = 0, but since the wait time of the own unit is determined to be 1 × BI from the lower two digits of ID = 1, the time is 0: 00 + 1 X Wait until it becomes BI, and issue a meter reading notification to the master unit. Although explanation in the middle is omitted, since the slave unit of ID029 that is directly subordinate to the master unit has its own wait time determined to be 29 × BI from the relay stage number = 0 and the ID lower two digits = 29, Waits until 0: 00 + 29 × BI, and calls for reading of the meter reading value to the master unit.

Since the slave unit of ID100 subordinate to the relay unit of ID10 determines that its own wait time is 30 × BI from the number of relay stages = 1 and the lower two digits of ID = 00, the time is set to 0: 00 + 30 × BI. Wait until it becomes, and call the meter reading value notification to the main unit. Since the slave unit with ID 200 subordinate to the relay unit with ID 20 has its own wait time of 60 × BI determined from the number of relay stages = 2 and the lower 2 digits of ID = 00, the time is 0: 00 + 60 × BI. Wait until it becomes, and call the meter reading value notification to the main unit. Thereafter, the calling is sequentially executed, and the slave having the ID of A29 subordinate to the relay having the ID of A0 is the slave that finally issues the meter reading value notification. Since this slave unit has been determined that the wait time of its own unit is 329 × BI from the relay stage number = 10 and the lower 2 digits of ID = 29, it waits until the time becomes 0: 00 + 329 × BI and returns to the master unit. Call the meter reading notification.

Thus, all 330 slave units have finished making calls, but if BI = 12.8 seconds, the time required for this is 330 × BI = 4224 seconds = 1 hour 10 minutes 24 seconds. However, in the example of FIG. 8, it is assumed that the slave device with ID 100 and the slave device with ID 200 fail to notify the meter reading value due to some communication failure. These two slave units execute the first retransmission after a predetermined call waiting time.

The slave unit of ID100 whose wait time at the time of initial transmission is 30 × BI sets a value obtained by adding 330 × BI to the wait time at the time of initial transmission as the first wait time for retransmission. That is, the wait time of the own device is determined as (330 + 30) × BI, and waits until the time becomes 0: 00+ (330 + 30) × BI, and the meter reading value notification to the parent device is called. The slave device with ID 200 whose initial transmission wait time is 60 × BI sets a value obtained by adding 330 × BI to the initial transmission wait time as the first retransmission wait time. That is, the wait time of the own device is determined to be (330 + 60) × BI, and waits until the time becomes 0: 00+ (330 + 60) × BI, and the meter reading value notification to the parent device is issued.

In the example of FIG. 8, it is assumed that, at the first retransmission, the ID100 handset succeeds in the meter reading notification, but the ID200 handset fails in the meter reading notification. The latter executes a second retransmission after a predetermined call waiting time.

The slave device with ID 200 whose first retransmission wait time is (330 + 60) × BI sets a value obtained by adding 330 × BI to the first retransmission wait time as the second retransmission wait time. That is, the wait time of the own device is determined to be (330 × 2 + 60) × BI, and waits until the time becomes 0: 00+ (330 × 2 + 60) × BI, and the meter reading value notification to the parent device is issued. In the example of FIG. 8, it is assumed that the slave unit with ID 200 succeeds in the meter reading value notification in the second retransmission.

As is clear from the above description, no communication collision occurs even if the master unit and the ten relay units in FIG. 1 do not control the meter reading value notification timing of the slave unit. There is no difference in this point in any of the states before and after the entry of the ID200 slave unit among the 330 slave units in FIG. In other words, it can be seen that this embodiment can flexibly cope with changes in the network configuration.

The wait time calculation formula can be changed according to the network configuration. For example, as shown in FIG. 1, even if the maximum number of slave units under each relay device is actually 30, allow a little margin and use the binary notation of the slave unit ID,
Wait time = BI x (number of relay stages x 32 + lower 5 bits of slave unit ID)
It is good.

Generally speaking, when M is the number of slave units that can be connected to each relay unit, and N = 0, 1, 2,..., M−1,
Wait time = BI x (number of relay stages x M + N)
It is. The value of N may be generated by a random function.

In addition, if the value of N coincides by chance in a plurality of slave units subordinate to the same repeater, a communication collision occurs in the meter reading value notification. However, even in such a case, it is possible to lead to successful communication with a high probability by the retransmission sequence described in FIG.

FIG. 9 is a timing chart in the case of 1-channel transmission in the wireless communication system of FIG. However, the relay device interposed between the parent device and the child device is not shown.

According to FIG. 9, the slave unit that has failed in the initial transmission retransmits the meter reading value at the timing of the first received beacon signal after the call waiting for a predetermined time. However, retransmission may fail for the same reason as the first transmission.

FIG. 10 is a timing chart in the case of 2-channel transmission in the wireless communication system of FIG. The base unit transmits a beacon signal by alternately using the A channel and the B channel. In the example of FIG. 10, it is assumed that a communication failure has occurred when the handset first transmits a meter reading value using the A channel. The slave unit that has failed in the initial transmission retransmits the meter reading value at the timing of the beacon signal first received on the B channel different from the A channel used for the initial transmission after the call waiting for a predetermined time. By the retransmission operation using a plurality of channels, the possibility of retransmission failure is reduced. Of course, it is possible to use more than two channels.

Note that it is convenient for the master unit that the time stamp included in the meter reading value information is not the transmission time from the slave unit but the meter reading time of the slave unit.

As described above, the meter-reading device according to the present invention has an effect of being able to efficiently and automatically process calls such as periodic meter-reading, and measures a plurality of usage amounts of electricity, gas, water, etc. This is useful as a technique for collecting meter reading value information from these meters.

DESCRIPTION OF SYMBOLS 1 Antenna 2 Transmission / reception part 3 Beacon transmission part 4 Link connection part 5 Control part 11 Antenna 12 Transmission / reception part 13 Beacon transmission part 14 Beacon reception part 15 Link connection part 16 Control part 21 Antenna 22 Transmission / reception part 23 Beacon reception part 24 Link connection part 25 Calling wait control unit 26 Control unit 27 Storage unit

Claims

A meter reading device that collects meter reading value information from a plurality of meters,
A synchronous system including a master unit, at least one repeater, and a plurality of slave units respectively associated with any of the plurality of meters and subordinate to any of the master unit and the repeater In the communication system, the master unit sequentially receives notification of meter reading value information from each of the plurality of slave units,
Each of the plurality of slave units is
A beacon receiving unit for receiving a beacon signal periodically transmitted from a subordinate of the slave unit among the master unit and the relay unit;
The wait time from when the meter reading event occurs until the meter reading value is notified is calculated according to the interval of the beacon signal and the number of stages of the relay device between the own device and the parent device, and the calculation And a call waiting control unit for controlling a call timing according to the wait time.
In the meter-reading apparatus of Claim 1,
Information indicating the number of stages of the relay device is included in the beacon signal received by the slave device.
In the meter-reading apparatus of Claim 1,
Each of the plurality of slave units further calculates the wait time using an identification number of the own unit.
In the meter-reading apparatus of Claim 1,
The meter reading device according to claim 1, wherein the meter reading event is an event based on a periodic meter reading setting received by the slave unit from the master unit.
In the meter-reading apparatus of Claim 1,
The time stamp included in the meter reading value information represents a meter reading time of the slave unit.
In the meter-reading apparatus of Claim 1,
Each of the plurality of slave units performs a retransmission operation up to a predetermined number of times after a further wait time when the meter reading value notification is not received by the master unit.
In the meter-reading apparatus of Claim 6,
The re-transmission operation is performed using a plurality of channels.
The meter-reading apparatus according to claim 7,
Each of the plurality of slave units retransmits the meter reading value information using a channel different from the channel used for initial transmission.
By operating as a slave unit subordinate to either the master unit or the relay unit in a synchronous communication system including the master unit and at least one relay unit, meter reading value information is sent to the master unit. A gas meter with a notification function,
A beacon receiving unit for receiving a beacon signal periodically transmitted from a subordinate of the slave unit among the master unit and the relay unit;
The wait time from when the meter reading event occurs until the meter reading value is notified depends on the interval of the beacon signal, the number of stages of the repeater between the own device and the parent device, and the identification number of the own device And a call weight control unit that controls the timing of the call according to the calculated wait time,
Information indicating the number of stages of the relay device is included in the beacon signal received by the slave device.