JP2001128256A - Automatic metering system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an automatic metering system that can reduce a communication cost while miniaturizing a master station and reducing the cost. SOLUTION: The automatic metering system S1 is provided with a master station 4 that can make communications with a home office station 1 at a 1st communication rate via a public phone network 2, slave stations 5 that can make synchronous communications with the master station 4 at a speed faster than the 1st communication rate via a wireless channel, and a meter device 7 that can communicate with the slave station 5 via a wired channel 6. When the home office station 1 transmits request data Dr to the meter device 7 via the master station 4 and the slave station 5, the meter device 7 can communicate reply data Da of the meter device 7 via the slave station 5 and the master station 4. The master station 4 inserts a synchronous code for synchronization communicates to request data Dra and transmits the resulting data to the slave station 5 while receiving the request data Dr from the home office station 1.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an automatic meter reading system for automatically measuring the usage of gas, water, electricity, and the like. The present invention relates to an automatic meter reading system capable of communicating communication data such as response data such as data and meter reading value data by wireless communication.

[0002]

2. Description of the Related Art In recent years, as a system for automatically reading meter reading values of gas meters and the like installed in general homes, etc.,
Automatic meter reading systems using wireless communication have been developed. The conventional automatic meter reading system generally includes a head office that controls various controls, a master station connected to the head office via a telephone line, and a plurality of master stations connected to the master station via a wireless line. It is composed of a slave station and a plurality of meter devices connected to each slave station via a wired line.

In this conventional automatic meter reading system, at the time of automatic meter reading, the head office communicates meter reading request data to a master station via a telephone line. In this case, the communication speed on the telephone line is 300 bps in order to maintain high communication quality.
(Bit per second). Next, the master station communicates the meter reading request data to the slave station via a wireless line. In this case, the wireless communication line is generally constructed by a specific low-power radio, and the communication speed of the specific low-power radio is 1200, which is higher than the communication speed of the telephone line.
bps and communication is performed by synchronous communication. For this reason, the master station communicates the meter reading request data to the slave station in accordance with the so-called accumulation relay method due to the difference between the two communication speeds. Specifically, the master station temporarily stores the meter reading request data transmitted from the headquarters station in the memory, and then transmits the meter reading request data stored in the memory to the slave station by synchronous communication via a wireless line. Send. Next, the slave station
The received meter reading request data is transmitted to the meter device via a wired line. Thereafter, the meter device transmits the meter reading value data to the slave station, and the slave station sends the meter reading value data to the master station.

On the other hand, the telephone line between the master station and the head office is kept connected, and the master station communicates the meter reading data transmitted from the slave station to the head office via the connected telephone line. I do. The head office absorbs meter reading data from all meter devices by performing these processes for each slave station.

[0005]

However, the conventional automatic meter reading system has the following problems. That is, in the conventional automatic meter reading system, the master station temporarily stores all the meter reading request data transmitted from the head office in the memory. For this reason, when the control unit of the master station is constituted by a one-chip microcomputer with a built-in memory, if the data capacity of the meter reading request data is large, the built-in memory cannot store the meter reading request data. For this reason, an external memory must be connected to the one-chip microcomputer, which causes a problem that the size of the master station is increased and the cost is increased. Also, until the head office absorbs the meter reading data from all the meter devices, the telephone line between the head office and the master station is continuously maintained in a connected state, which causes a rise in communication costs. There is also a problem.

The present invention has been made in view of the above problems, and has as its main object to provide an automatic meter reading system capable of reducing communication costs while reducing the size and cost of a master station. I do.

[0007]

In order to achieve the above object, an automatic meter reading system according to claim 1 comprises a master station capable of communicating with a head office via a public telephone network at a first communication speed; A slave station for performing synchronous communication with the master station at a speed higher than the first communication speed via a wireless line, and a meter device capable of communicating with the slave station via a wired line; Automatic meter reading system configured to be able to communicate the response data of the meter device to the head office via the slave station and the master station when request data is transmitted from the head office to the meter device via the station and the slave station. Wherein the master station inserts a synchronization code for synchronous communication into the request data and transmits the request data to the slave station while receiving the request data from the head office. in this case,
The `` slave station '' includes a slave station having both a function as a terminal device for transmitting response data of the meter device and a function as a relay device, and only a function as a terminal device without having a function as a relay device. Includes slave stations that have In addition, a slave station having a relay function is provided between the master station and the slave station, and the slave station with respect to the slave station as a terminal device,
The request data in which the synchronization code is inserted can also be transmitted.

The automatic meter reading system according to a second aspect is characterized in that, in the automatic meter reading system according to the first aspect, the master station performs error correction coding processing on the received request data and transmits the data to the slave station.

The automatic meter reading system according to a third aspect is characterized in that in the automatic meter reading system according to the second aspect, the error correction encoding process is performed by a Hagerberger code.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of an automatic meter reading system according to the present invention will be described below with reference to the accompanying drawings.

An automatic meter reading system S1 shown in FIG. 1 is a system for automatically reading, for example, gas usage and the like, and is conceptually a head office having a central collection device 1a composed of a host computer and the like. 1, a master station 4 provided in the apartment house 3 and connected to the head office 1 via a public line network 2 such as a telephone line, and a parent station provided in the apartment house 3 via a wireless line. A plurality of slave stations 5 connected to the station 4,
It comprises a meter device 7 connected to each slave station 5 via a wired line 6.

In this case, the master station 4 is the first station in the present invention.
The meter reading request data Dr corresponding to the request data in the present invention and the meter reading value data D corresponding to the response data in the present invention at a communication speed of 300 bps corresponding to the communication speed of the present invention.
a communication data Dc including the communication data Dc including the communication data Dc between the transmission device 4a and the transmission device 4a via the two-wire type wired line 4c.
The wireless master station 4b communicates at a communication speed of 00 bps and synchronously communicates communication data Dc with the slave station 5 at a communication speed of 1200 bps. Further, as shown in FIG. 2, the wireless master station 4b includes, for example, an antenna 11 for transmitting and receiving a radio wave in a 400 MHz band, an antenna switch 12, a meter reading request data Dra output from a control unit 15 described later, and the like. A transmission unit 13 that modulates and transmits a carrier wave with communication data Dc that includes communication data Dc and communication data Dc that receives wireless signals and includes response data such as meter reading value data Da and the like.
And a control unit 1 that controls the operations of the transmission unit 13 and the reception unit 14 and creates the communication data Dc.
5 is provided.

In this case, the control unit 15 is composed of, for example, a one-chip microcomputer, and conceptually, a C that communicates the communication data Dc with the transmission device 4a.
A PU 15a and an RO for storing an operation program of the CPU 15a and various data for creating communication data Dc.
M15b and a built-in RAM 15c for temporarily storing communication data Dc during communication.

In the master station 4, when the communication data Dc is output from the central collection device 1a via the transmission device 4a, the control unit 15 creates new communication data Dc for the slave station 5. Specifically, for example, when the meter reading request data Dr is output from the central collection device 1a, the control unit 15
As shown in FIG. 4, meter reading request data Dra destined for the slave station 5 composed of a bit synchronization code section, a frame synchronization code section, a header section, an information section, and a termination code section is created. In this case, the bit synchronization code section is “0”, “1” for synchronizing bits in communication with the CPU 16a (see FIG. 3) functioning as a modem of the slave station 5.
For example, four bytes of a 1-bit bit synchronization code PADL composed of repetition of data are inserted and formed. The frame synchronization code section includes a frame synchronization signal SY for data synchronization.
For example, N (16H) is formed by inserting 2 bytes. The header section includes a 1-byte text information TEXT (1) into which an STX code indicating the beginning of the text information and the own station number of the slave station 5 as a destination are inserted.
, TEXT (2). Further, the information section includes one-byte text information TEXT (3) to TEXT (N) into which various information including meter reading request data and the like are inserted.
And 1 byte ET meaning the end of the text information part
It is composed of an X code and a one-byte BCC code for error test. The termination code part is formed of a one-byte termination code PADT indicating the end of communication data.

The control unit 15 also stores the meter reading request data Dr.
a, the header information and the text information transmitted from the central collection device 1a via the transmission device 4a are error-correction-encoded by the Hagerberger code for error correction, and then the encoded header information and text are encoded. The information is inserted into the header section and the information section, respectively, to create the meter reading request data Dra. Thereby, the reliability of data communication between the wireless master station 4b and the slave station 5 via the wireless line can be improved. In addition, the Hagerberger code has an advantage that error correction coding can be performed for each byte. Therefore, each time 1-byte text information is output from the transmission device 4a, the text information is sequentially coded to thereby be described later. In addition, the immediacy of communication is realized. Note that a BCH code may be used instead of the Hagerberger code.

On the other hand, in the automatic meter reading system S1, the communication between the wireless master station 4b and the slave station 5 via the wireless line is changed to the communication between the central collection device 1a and the transmission device 4a via the public line network 2. The communication speed is higher than the communication speed. For this reason, the wireless master station 4b performs the reception processing of the meter reading request data Dr output from the transmission device 4a, the processing of creating the meter reading request data Dra, and the processing of transmitting the meter reading request data Dra to the slave station 5 in parallel. In this case, in order to perform synchronous communication, it is necessary to continuously transmit the meter reading request data Dra, but a situation occurs in which a part of the meter reading request data Dra is not transmitted from the transmission device 4a. In such a case, since the meter reading request data Dra cannot be transmitted continuously, the synchronization between them is lost. For this reason, the CPU 15a transmits, for example, a 2-byte synchronization code SYN during a gap period in which data to be transmitted is not received.
(16H) is inserted. Thus, the slave station 5 can stably maintain communication synchronization, and can restore the original meter reading request data Dra by deleting the synchronization code SYN.

As shown in FIG. 3, the slave station 5
b, the antenna 11, the antenna switch 12, the transmission unit 13, and the reception unit 14, each having the same configuration as the components of the wireless master station 4 b, and a control unit 16. In this case, the control unit 16 is formed of, for example, a one-chip microcomputer, and communicates with the meter device 7 with the meter reading request data Dra and the meter reading value data Da.
RO that stores the operation program of 16a, own station number, etc.
M16b and a built-in RAM 16c for temporarily storing both data Dra and Da during communication.
On the other hand, as shown in FIG. 1, the meter device 7 is disposed, for example, between the gas pipe 8 and a gas appliance (not shown) to generate and store the meter reading value data Da corresponding to the gas usage. ,
When the meter reading request data Dra transmitted from the slave station 5 is received, the meter reading value data Da stored in the internal memory is transmitted to the slave station 5.

Next, the overall operation of the automatic meter reading system S1 will be described focusing on the master station communication processing by the wireless master station 4b and the slave station communication processing by the slave station 5.

First, in the master station communication process, the CPU 15a of the wireless master station 4b determines whether or not the meter reading request data Dr has been received from the transmission device 4a as shown in FIG. 5 (step 21). In this case, when the meter reading request data Dr is transmitted from the central collection device 1a of the head office 1 to the parent station 4 via the public line network 2, the transmission device 4a receives the meter reading request data Dr while receiving the meter reading request data Dr. The data Dr is sequentially output to the wireless master station 4b. At this time, the CPU 15a
When the STX code shown in FIG.
It is determined that r has been received. After that, the public network 2 between the central collection device 1a and the transmission device 4a transmits the meter reading value data D from all the meter devices 7 to the central collection device 1a.
The connection state is maintained until a is collected.

Next, the CPU 15a determines, based on the received carrier level signal SC output from the receiving section 14, whether or not the same frequency as the transmission frequency of its own station is being used (step 22). When it is determined that the communication is in use, the reception carrier level signal SC is monitored until the communication is completed. On the other hand, when it is determined that it is not used, C
As shown in FIG. 7, the PU 15a first transmits the bit synchronization code PADL, the synchronization SYN (1) code as the frame synchronization signal, and the synchronization SYN (2) code while creating the meter reading request data Dra, as shown in FIG. 13 and sequentially transmitted via the antenna 11 (step 2).
3). Next, the CPU 15a performs error correction coding on the STX code using the Hagerberger code (step 2).
4) Transmit the encoded STX code (step 2)
5).

Subsequently, the CPU 15a determines whether or not text information to be transmitted to the slave station 5 has been received (step 26). When it is determined that the text information to be transmitted has not been received, the CPU 15a
YN is inserted into the meter reading request data Dra and transmitted (step 27). Conversely, when it is determined that the
U15a determines whether the data to be transmitted has been completed (step 28). In this case, the CPU 15a
When the reception of the TX code is recognized, it is determined that the text information to be transmitted has ended. Next, the CPU 15a repeats the above step 24 until the input of the ETX code is recognized.
28 are repeated. As a result, the master station 4 transmits the text information TEX sequentially transmitted from the transmission device 4a.
Each time one byte of T (1),..., TEXT (M),..., TEXT (N) is received, the one-byte text information is error-corrected by the Hagerberger code (step 2).
4), as shown in FIG. 7, the encoded text information TE
XT (1) to TEXT (N) are sequentially transmitted (step 2).
5) along with the text information TEXT (1)-TEXT
A synchronization code SYN is appropriately inserted between (N) and transmitted (step 27). Next, when the ETX code is received, the CPU 15a recognizes the end of the text information (Step 28), and transmits the ETX code after error-correcting the ETX code (Step 24) (Step 25). Further, the CPU 15a transmits the BCC code transmitted thereafter after error correction coding (step 24) and (step 25).

On the other hand, the slave station 5 executes the slave station communication processing shown in FIG. 6 in parallel with the master station communication processing by the master station 4. In this process, the CPU 16a of the slave station 5 determines whether a carrier having the same frequency as the reception frequency is being transmitted based on the reception carrier level signal SC output from the reception unit 14 (step 31). In this case, the CPU 16
a is the bit synchronization code PADL and the frame synchronization signals SYN (1), SY
It is determined whether or not N (2) exists (step 32). When it is determined that N (2) exists, synchronous communication is started, and when it is determined that N (2) does not exist, this processing is terminated. Next, each time the STX code and the text information TEXT (1), TEXT (2) as the header part are sequentially received, the CPU 16a performs error correction decoding (step 33), and converts the text information TEXT (1), TEXT (2). It is determined whether or not the data is the meter reading request data Dra addressed to the own station (step 3).
4). When it is determined that the address is not addressed to the own station, the CPU 16
a ends this processing.

When it is determined that the address is addressed to the own station, the CPU 16
a skips the error correction decoding process (step 35) and sets the synchronization code S in the error correction decoded text information.
It is determined whether or not YN exists (step 36). When it is determined that YN exists, the synchronization code SYN is discarded (step 37). Next, the CPU 16a proceeds to FIG.
As shown in (5), the STX code and the text information TEXT (1) and TEXT (2) as the meter reading request data Dr are sequentially transmitted to the meter device 7 (step 38). Then C
The PU 16a determines whether or not the data to be output has been completed (Step 39). In this case, the CPU 16a
Until the reception of the ETX code is recognized, the above steps 35 to
Step 39 is repeatedly executed. Thereby, the text information TEXT (3) to be transmitted thereafter, TEXT
(M)... Each time one byte of TEXT (N) is received, the text information is error-correction decoded (step 35), and the synchronization code SYN inserted between the text information is discarded (step 37). , Text information TEXT (3)
···, TEXT (M) ···, TEXT (N)
(Step 38). On the other hand, when the input of the ETX code is recognized, it is determined that the data to be transmitted has been completed (step 39), and this processing ends.

When detecting the input of the meter reading request data Dr, the meter device 7 reads the meter reading value data Da stored in the built-in memory via the wired line 6 into the CPU 16 of the slave station 5.
output to a. At this time, the CPU 16a performs the same process as the error correction encoding process on the meter reading request data Dr and the insertion process of the synchronization code SYN on the meter reading request data Dr by the CPU 15a of the wireless master station 4b on the meter reading value data Da. Output to the unit 13. As a result, the transmission unit 13 transmits the wireless signal modulated with the meter reading value data Da to the master station 4.
On the other hand, in the master station 4, the receiving unit 14 receives the radio signal and demodulates the radio signal into the meter reading value data Da.
Is output to the CPU 15a. At this time, the CPU 15a
Transmits the meter reading value data Da to the transmission device 4a via the wired line 4c while performing error correction decoding on the meter reading value data Da and discarding the synchronization code SYN. In this case, the communication between the slave station 5 and the wireless master station 4b via the wireless line is performed at a communication speed (300 bps) higher than the communication speed between the meter device 7 and the CPU 16a of the slave station 5 (300 bps). In addition, the error correction decoding process and the discarding process of the synchronization code SYN and the transmission process of the meter reading value data Da to the transmission device 4a can be easily performed in parallel. Next, the transmission device 4a transmits the meter reading value data Da to the central collection device 1a via the public line network 2.

As a result, the central collection device 1a collects the meter reading value data Da from the meter device 7 connected to the slave station 5 while maintaining the line connection with the transmission device 4a. By performing the above processing for all the slave stations 5, the central collection device 1 a collects the meter reading value data Da stored in all the meter devices 7.

As described above, according to the automatic meter reading system S1, the central collection device 1a collects the meter reading value data Da from all the meter devices 7 while maintaining the line connection with the transmission device 4a. can do. In the automatic meter reading system S1, the master station 4 is connected to the central collection device 1
While receiving the meter reading request data Dr transmitted from a, the meter reading request data Dra is sequentially transmitted to the slave station 5. For this reason, the communication time from the start of transmission of the meter reading request data Dr by the head office 1 to the reception of all the meter reading request data Dr by the meter device 7 is as shown in FIG.
As shown in the figure, the head office 1 sends the meter reading request data D to the master station 4.
This time is slightly longer than the communication time required to transmit r. Therefore, compared to the conventional storage relay method, the communication time can be sufficiently reduced,
The connection fee to the public line network 2 can be reduced, whereby the running cost in the automatic meter reading system S1 can be sufficiently reduced.

The central collection device 1a and the transmission device 4
a is performed at a communication speed lower than the communication speed between the wireless master station 4b and the slave station 5, the synchronization code SYN is set to the communication data D such as the meter reading request data Dra.
By inserting it in c, communication synchronization between the master station 4 and the slave station 5 can be stably maintained. Further, the wireless master station 4b communicates with the communication data Dc such as the meter reading request data Dra.
Are sequentially transmitted to the RAM 15 in the control unit 15.
Since there is no need to store such a large amount of data in c, the control unit 15 can be configured with a general-purpose one-chip microcomputer having a small-capacity RAM. As a result, the size and cost of the master station 4 can be reduced. Similarly, since the slave station 5 successively transmits the communication data Dc such as the meter reading request data Dr to the meter device 7, it is not necessary to store the data having such a large capacity in the RAM 16c in the control unit 16. The control unit 16 can be configured by a general-purpose one-chip microcomputer having a built-in capacity RAM. As a result, the size and cost of the slave station 5 can be reduced.

The present invention is not limited to the configuration shown in the embodiment of the present invention. For example, communication data Dc communicated in the automatic meter reading system according to the present invention.
Is not limited to the types and data structures shown in the embodiment of the present invention, and it is needless to say that it can be changed and added as appropriate. Further, the configurations of the transmission unit 13 and the reception unit 14 in the wireless master station 4b and the slave station 5 are not limited, and any known circuit can be adopted. Further, the central collection device 1a
In addition, the communication speed between the transmission device 4a and the communication speed between the master station 4 and the slave station 5 is not limited to the speed described in the embodiment of the present invention, and can be appropriately changed. Can also be defined at any frequency. Further, not only a wireless line using a single frequency but also a wireless line using a multi-channel access method can be constructed.

[0029]

As described above, according to the automatic meter reading system of the first aspect, the master station inserts the synchronization code for synchronous communication into the request data while receiving the request data from the head office. By transmitting to the station, communication synchronization between the master station and the slave station can be stably maintained, and there is no need to store data of such a large capacity in the master station. As a result, it is possible to reduce the size of the master station and reduce the cost.

According to the automatic meter reading system according to the second aspect, the master station performs error correction coding processing of the requested data and transmits the data to the slave station, so that the master station and the slave station can communicate with each other via a wireless line. Can improve the reliability of data communication.

Further, according to the automatic meter reading system according to the third aspect, the error correction encoding process is performed by the Hagerberger code, so that each time 1-byte text information is output from the head office, the text information is sequentially encoded. Therefore, immediacy of communication can be realized.

[Brief description of the drawings]

FIG. 1 is an automatic meter reading system S according to an embodiment of the present invention.
1 is a block diagram showing a configuration of FIG.

FIG. 2 is an automatic meter reading system S according to an embodiment of the present invention.
1 is a block diagram illustrating a configuration of a wireless master station 4b in FIG.

FIG. 3 is an automatic meter reading system S according to an embodiment of the present invention.
1 is a block diagram showing a configuration of a slave station 5 in FIG.

FIG. 4 is a data structure diagram of meter reading request data Dra created by a wireless master station 4b.

FIG. 5 is a flowchart of a master station communication process by the master station 4.

FIG. 6 is a flowchart of a slave station communication process by the slave station 5.

FIG. 7: headquarters station 1, master station 4, slave station 5, and meter device 7
It is an explanatory view showing a communication procedure between them.

[Explanation of symbols]

 Reference Signs List 1 head office 2 public line network 4 master station 4a transmission device 4b wireless master station 5 slave station 6 wired line 7 meter device Da meter reading value data Dr meter reading request data Dra meter reading request data S1 automatic meter reading system SYN synchronization code SYN

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Akira Koizumi 3967-1010 Wada, Matsumoto-shi, Nagano Toyo Keiki Co., Ltd. (72) Inventor Tsutomu Yagami 3967-1010, Wada, Matsumoto-shi, Nagano Toyo Keiki Co., Ltd. 72) Inventor Hideki Motoyama 1163, Shimo-Himei, Inari-cho, Nagano City, Nagano Prefecture Inside Nagano Japan Radio Co., Ltd. DD02 DE13 GG01 GG06 GG07 GG08 5K048 AA03 BA36 DA02 DB01 DC01 DC07 EA14 EB04 EB10 HA01 HA02 5K067 AA41 AA42 BB27 DD25 EE02 EE10 HH05 HH21 HH22 HH26 5K101 KK12 LL01

Claims (3)

[Claims] 1. A first communication with a headquarters office via a public telephone network.
A slave station capable of performing communication at a communication speed higher than the first communication speed between the master station and the master station via a wireless line, and the slave station via a wired line. And a meter device capable of communicating with the master station and the slave station, when request data is transmitted from the headquarters station to the meter device via the slave station, the request data is transmitted through the slave station and the master station. In the automatic meter reading system configured to be able to communicate the response data of the meter device to the headquarters station, the master station receives the request data from the headquarters station, and includes a synchronous communication An automatic meter reading system, wherein a synchronization code is inserted and transmitted to the slave station. 2. The automatic meter reading system according to claim 1, wherein the master station performs error correction coding processing on the received request data and transmits the request data to the slave station. 3. The automatic meter reading system according to claim 2, wherein the error correction coding processing is performed by a Hagerberger code.