JPS62205500A - Electronic type automatic telemetering system - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention is a system for automatically reading electronic meters such as electronic water meters installed in remote areas from a center via a bidirectional CATVlt line. Related to electronic meter automatic meter reading system.

(Prior Art) Conventionally, this type of electronic meter automatic meter reading system uses an RF terminal transmitter that modulates and demodulates an RF band doubled signal for each electronic meter 40 located at a remote location, as shown in FIG. 4, for example. One terminal configuration is used in which a transmitter 41 is provided, and each RFF terminal transmitter 4
1 is multi-connected to the bidirectional CATV main line 42 and connected to the center 43 via the center polling control section 44. Then, in the remote automatic meter reading, one RFF terminal transmitter 41 is selected by a downstream meter reading activation signal including the RFF terminal transmitter address from the center 43, and this selected RFF terminal transmitter activates DC activation to the electronic meter. The system uses a sequential polling method in which each RFF end transmitter sequentially performs the following operations: modulating the meter reading obtained from the electronic meter into the upstream RF band and sending a reply to the center 43 via the bidirectional CATV main line 42. There is.

[Problem that the invention seeks to solve]

However, the conventional automatic meter reading method described above requires the same number of RFF terminal transmitters 41 as the number of electronic meters 40, and the RFF demodulation section in each RFF terminal transmitter 41 is connected to a tap-off terminal of the CATV main line 42, etc. Since multiple connections are made to the RFF end transmitters 41, concentrated sink noise such as carrier leakage via the CATVI # line to the center 43 increases due to the large number of RFF end transmitters 41, and this puts a burden on the RFF end transmitters 41 due to their characteristics. As a result, the noise distribution for line tolerance becomes stricter, and as a result,
There is a drawback that the number of RFF end transmitters 41, that is, the number of electronic meters 40 connected is limited.

Furthermore, since the RF#i end transmitter 41 is added to each electronic meter, there is also the disadvantage that the RFF demodulation section is duplicated, which is economically wasteful.

Furthermore, the electronic meter output is NR for electronic water meters.
It is a Z baseband signal (DC NRZ pulse signal), and the receiving impedance is 50Ω.
Therefore, the distance of the meter cable 45 connecting the RFF end transmitter 41 and the electronic meter 40 cannot be increased, and there is also the disadvantage that it is difficult to arrange the electronic meter 40 or the RFF end transmitter 41.

The present invention has solved these conventional drawbacks, and its purpose is to provide an automatic system that is economical in structure, can connect many electronic meters, and is easy to place electronic meters. The purpose is to provide a meter reading system.

[Means for solving problems]

In order to achieve the above object, the electronic meter automatic meter reading system of the present invention connects an electronic meter that is installed in a remote location and outputs a meter reading value of an NRZ baseband signal in response to DC activation No. 13 to a two-way CATV. In the electronic meter automatic meter reading system, which performs remote automatic meter reading from the center via #m, multiple common RFF changers are connected to the bidirectional CA'r V main line connected to the center, and each common RFF
Multiple electronic meters are connected to each switching device via communication cables, relay boxes, and meter cables, and a downlink electronic meter reading activation modulation signal in the RF band containing the common RFF switching device address and electronic meter address is sent from the center. Once sent, the common RFF changer having the common RFF changer address selectively receives the meter reading activation modulation signal, and the common RFF changer that has selectively received the signal sends a connection response to the center and reads the electronic meter. An AC start signal is sent to the communication cable corresponding to the electronic meter address included in the start modulation signal, and the relay box that receives the AC start signal transmits DC current to the electronic meter connected to its own relay box via the meter cable. When the start signal is sent and the meter reading value of the NRZ baseband signal is sent from the electronic meter, it is converted into an alternating current signal and sent to the common RFF changer via the communication cable, and the meter reading of the alternating current signal is performed. The common RFF changer that receives the value is configured to modulate the meter reading value into the RF band using the data code as it is and send an upstream reply to the center.

[Effect]

Since multiple electronic meters are connected to one common RFF changer, the common RFF
The number of FF changers is smaller than the number of conventional RFF terminal transmitters, which reduces concentrated sink noise such as carrier leakage via the CATV main line to the center, and as a result, the number of electronic meters connected is reduced. can be increased, and also
Since a common RF switch is shared by multiple electronic meters, the configuration is economical. Furthermore, a relay box is installed between the common 111i RF switch and the electronic meter, and this converts the DC meter reading signal from the electronic meter into an AC signal, so the distance between the common RF switch and the electronic meter can be reduced. It can be made longer, making it easier to place electronic meters, etc.

〔Example〕

Next, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a block diagram of an embodiment of the present invention, in which the present invention is applied to automatic meter reading of an electronic water meter.

As shown in FIG. 1, this embodiment includes a center 11, a center polling control unit 10 connected to the center 11, a bidirectional CATV main line 9 connected to this, and this CAT
A plurality of common RF switching devices 8 multi-connected to the V main line 9
-1 to t3-m. Common RF switch 8-1~B
-11 is composed of an RF modem 7, a processing section 6, and a meter side interface 5, and the RF modem 7 is connected to the CA
It is connected to the TV main line 9, and the meter side interface 5 is connected to the communication cables 4a to 4n. This meter side interface 5 performs an operation of connecting one of the plurality of communication cables 43 to 4n to the processing section 6 in response to an instruction from the processing section 6. Note that as the communication cables 4a to 4n, it is also possible to use an interposed pair of CATV coaxial cables or a cable equivalent to a separate mesosenser.

Each of the above connection cables 4a to 4n has a relay box 3.
a to 3n are connected, and electronic water meters 1a to 1n are connected to each relay box via meter cables 2a to 2n.

FIG. 2 is a basic meter reading sequence operation chart in the system of FIG. 1, and the same reference numerals as in FIG. 1 indicate the same parts. The operation of this embodiment will be described below with reference to FIGS. 1 and 2.

When the center activation 12 is performed from the center 11 in FIG. 1, a meter reading activation modulation signal that is modulated in the downward direction by the RF band center frequency conversion process 13 is sent from the center polling control unit 10 to the CATV main line 9 in FIG. Ru. This meter reading activation modulation signal includes a meter address for specifying the electronic water meter to be read and the address of the common RF switch connected to the electronic water meter. reaches all the common RF switchers 8-1 to 8-ffl multi-connected to the CATV trunk 1i19, but only one whose address matches the common RF switcher address included in the meter reading activation modulation signal. Common R
It is selectively received by the F switch. FIG. 2 shows a case where the meter reading start modulation signal is received by the common RF switch 8-1. When the common RF switch 8-1 receives the meter reading start modulation signal, it first connects the RF modem 7 and the processing unit 6. and R in Figure 2.
Inverse conversion processing 14 of F-band terminal frequency is performed, and common 111
The RF switch connection VE response 15 is sent to the center 11 via the CATV main line 9 and the RF band center frequency inverse conversion process 16 of the center polling control unit 10, and the center 11 performs a center common RF switch connection determination 17.

On the other hand, in the common RF switch 8-1, the meter-side interface 5 selects and translates the communication cable 4a that matches the specified meter address according to the instruction from the processing unit 6, and transmits the data shown in FIG. 2 via the selected communication cable 4a. AC activation signal 18 is sent to relay box 3a. When the relay box 3a determines in the AC start signal reception determination process 19 that the AC start signal 18 has been received, it performs the DC start process 20 shown in FIG. 2 on the electronic water meter a via the meter cable 2a, and starts the DC start signal. Send a signal.

When electronic water meter a receives the DC activation signal,
The electronic meter reception process 21 causes the electronic meter to switch to a transmission operation, and the electronic meter reading data transmission process 22 transmits the meter reading as an NRZ baseband signal to the relay box 3a via the meter cable 2a.

When the relay box 3a receives the meter reading NRZ baseband signal from the electronic water meter a, it converts the NRZ signal into an alternating current signal through an alternating current signal sending process 23, and sends the converted alternating current signal to the common RF switch 8-1.

The common RF switch 8-1 receives the NR signal converted into the AC signal.
When the Z signal is received, the RF band conversion process 24 leaves the meter reading data code unchanged and converts it to f? It is modulated on the upstream side of the F band and sent to the CATV main line 9.

CATV trunk! The RF modulated signal sent to wI9 is demodulated by RF band inversion processing 25 of center polling control section 10, and center 11 performs electronic meter reading value judgment 26 of electronic water meter 1a based on this demodulated signal.

Next, if the center 11 needs to read another electronic water meter, it repeats the same operation as described above.

FIG. 3 shows an electrical meter reading timing chart when the meter reading sequence shown in FIG. 2 is carried out. After the common RF switch 8-1 receives the downlink common RF switch response 27 message, the uplink common RF switch connection response 28 is sent to the center 11, and then the relay box input AC signal which is the output of the relay box 3a Electronic meter DC start 3 by 29
0 is applied to the electronic water meter 1a, and an upstream electronic meter reading value output signal 31 is sent from the electronic water meter la.
-1°CATlf line 9. The data is received by the center 11 via the center polling control unit 10.

[Effects of the Invention] As explained above, the present invention has a configuration in which a conventional RF terminal transmitter is separated into a common RF switch and a relay box, and a plurality of electronic meters are connected to one common RF switch. Therefore, the common R connected to the bidirectional CATV trunk line
The number of F switchers is smaller than the number of conventional RF terminal transmitters, which can reduce concentrated sink noise such as carrier leakage via the CATV main line to the center, and as a result, the number of electronic meters connected can be reduced. It has the effect of increasing the In addition, since the common RF91 switch is shared by multiple electronic meters, the configuration is economical.Furthermore, a relay box is installed between the common RF switch and the electronic meter, and the electronic meter is connected to the common RF91 switch. Since the DC meter reading signal is converted into an AC signal, the distance between the common RF switch and the electronic meter can be increased, and the electronic meter can be easily arranged.

[Brief explanation of drawings]

FIG. 1 is a block diagram of one embodiment of the present invention, and FIG. 2 is a block diagram of an embodiment of the present invention.
Basic meter reading sequence operation chart 1 in the system shown in the figure, Figure 3 is an electrical meter reading timing chart when the meter reading sequence in Figure 2 is carried out, and Figure 4 is an explanatory diagram of the conventional system. be. In the figure, 1a to 1n...electronic water meter, 2a
~2n...Meter cable, 3a~3n...Relay box, 4a~4n...Connection cable, 5...Meter side interface, 6...Processing unit, 7...I'2
F modem, 8-1 to 8-m ・= common RF switch, 9-
CA TV main line, 10...center polling control unit, 11...center.

Claims (1)

[Scope of Claims] An electronic meter that is installed in a remote location and outputs a reading value of an NRZ baseband signal in response to a DC start signal, and that automatically reads the meter remotely from a center via a bidirectional CATV main line. In the automatic meter reading system, multiple common routes are connected to the bidirectional CATV main line connected to the center.
In addition to connecting multiple F switching devices, multiple electronic meters are connected to each common RF switching device via communication cables, relay boxes, and meter cables, and the common RF switching device address and electronic meter address are sent from the center. When a downlink electronic meter reading activation modulation signal in the RF band is sent, the common RF switch with the common RF switching device address selectively receives the meter reading activation modulation signal, and the common RF switching device that selectively received the meter reading activation modulation signal transmits the meter reading activation modulation signal to the center. At the same time, an AC start signal is sent to the communication cable corresponding to the electronic meter address included in the electronic meter reading start modulation signal. A DC activation signal is sent to an electronic meter connected via a cable, and when a meter reading value of an NRZ baseband signal is sent from the electronic meter, it is converted into an AC signal and communicated to the common RF switch. The common RF switching device that receives the meter reading value of the AC signal transmitted through the cable is configured to modulate the meter reading value into the RF band with the data code as it is and send an upstream reply to the center. Electronic meter automatic meter reading method.