JPH0325067B2 - - Google Patents

Description

[Detailed Description of the Invention] [Technical Field of the Invention] The present invention relates to a data collection system that collects measurement data such as water level, electricity, water supply, etc. measured at a plurality of measurement terminals using a communication line, and in particular, This invention relates to a data collection system with improved means.

[Technical Background of the Invention] Conventionally, there is a data collection system that collects measured quantities measured at a plurality of measurement terminals using a communication line, such as a telephone line. For example, if you want to centrally monitor water levels, flow rates, or water quality measurements at multiple points on a river, you can install terminal devices that store the measured amounts as measurement data at each point in the river, and then A central device (center device) that is stored in memory and collects measurement data is provided, and the center device calls each terminal device via a communication circuit to collect the measurement data of each point in the center device. In addition, such a data collection system with multiple measuring points can be used in many ways, such as calculating the amount of electricity, water, gas, etc. used by each household in an apartment complex, or measuring the temperature at each fixed measurement point of mechanical equipment. It has been applied over the years.

FIG. 4 is a configuration diagram of a conventional data collection system. This data collection system uses telephone lines, and a center processing device 100 is connected to an exchange 102 in a telephone exchange network via a network control device 101 of a telephone communication network.
from the terminal side exchange 10 via the telephone line 103.
4 are connected. And this exchange 104
A plurality of network control devices 105 (only one network control device is shown in FIG. 4) are connected to the network control device 105, and one terminal device 106 is connected to this network control device 105.
Note that the network control devices 101 and 105 are connected to the center processing device 100, the terminal device 106 side, and the telephone 10 side.
7 and 108. Therefore, when collecting measurement data, the center processing device 100 sends a signal indicating the dial of the network control device 105 connected to the terminal device 106 to which data should be collected to each network control device 105, and upon receiving this signal, Network control device 105 now able to communicate
Measurement data is transmitted from the terminal device 106 through the terminal device 106.

[Problems with the Background Art] As described above, since only one terminal device 106 is connected to the network control device 105, when the number of measurement terminals, that is, terminal devices 106 increases, a plurality of network control devices 105 are connected to the exchange 104. There is a problem in that it requires connection, which increases the equipment cost.
Therefore, in order to solve this problem, it is conceivable to commonly connect a plurality of terminal devices 106 to the network control device 105. However, if a plurality of terminal devices 106 are commonly connected, the center processing device 1
Since the calling signal etc. from 00 is applied to all terminal devices 106 in parallel, one terminal device 1
There is a drawback that the level of the signal input to 06 is lowered. In particular, when the distance between the network control device 105 and the terminal device 106 is long, the level drop becomes large.

[Object of the invention] The present invention has been made based on the above circumstances, and
The purpose is to provide an economical data collection system that allows long-distance transmission even when a plurality of terminal devices are connected.

[Summary of the Invention] The present invention provides a center device, a network control device that receives a dial signal sent from the center device and sends out a paging signal, and a relay device connected to the network control device via a communication circuit. It is equipped with an amplifier device and a plurality of terminal devices that are connected to this relay amplifier device by a multi-drop method and each stores measurement data. The relay amplifier has a function to collect measurement data sent from A paging detection circuit connected to the line connection switch and set to a relatively high amplification degree according to the number of terminal devices connected and the distance to the terminal devices, and amplifying the data request signal transmitted through the communication line. 1st
an amplifier, a second amplifier connected in parallel to the first amplifier and set to a relatively low amplification degree to amplify the measurement data from each terminal device, and each of the first and second amplifiers. Each switch commonly connected to the input/output terminal receives a detection signal from the call detection circuit, switches each switch to the first amplifier side, and then detects the level of the data request signal and the measured data to output each switch. This data collection system has a control unit that controls switching of a changeover switch, and each terminal device has a function of receiving a data request signal and transmitting measurement data to achieve the above object.

[Embodiment of the Invention] Hereinafter, an embodiment of the data collection system according to the present invention will be described with reference to FIGS. 1 to 3. FIG. 1 is a configuration diagram of the data collection system. This data collection system uses a telephone line as a communication line, similar to the system shown in FIG. In FIG. 1, reference numeral 1 denotes a center device, which uses polling to collect measured data stored in terminal devices _2-1 to 2 _-o (described later) (e.g., river water level, water volume, electricity, water supply, etc. in each household, etc.). It has the function of collecting data (gas consumption) and processing this measurement data into a state that is easy to manage. An exchange 4 in a telephone exchange network is connected to the input/output end of the center device 1 via a network control device 3 of the telephone communication network, and this exchange 4 is connected to an exchange 6 on the terminal side via a telephone line 5. has been done. The network control device 3 has the function of connecting to the terminal devices 2 _-1 to 2 _-o designated by the center device 1 via the exchanges 4 and 6, and also controlling switching between the center device 1 side and the telephone 7. It has

Now, a plurality of relay amplification network control devices 10 are connected to the exchange 6. Note that, due to the simplicity of the drawing, only one relay network control device 10 is shown in FIG. 1. Then, the relay network control device 10
A plurality of the terminal devices _2-1 to 2- _o are connected to each other by a multi-drop method. By the way, this relay network control device 10 has the function of controlling each terminal device 2 _-1 sent from the center device 1 in addition to the normal network control function.
~2 _-o Amplify the data request signal and send it to each terminal device 2 _-1 ~ _{2 -o} , and amplify the measurement data signal sent from the terminal device 2 _-1 ~ 2 _-o and send it to the center device 1 It has a function to send to. Specifically, the configuration is as shown in FIG. That is,
The call detection circuit 11 detects a call signal (a signal for ringing a bell in a telephone, 16 Hz) to call the relay amplification network control device 10, and switches the line connection switch 12.
This is to put the in the closed state. Amplifiers 13 and 14 are connected in parallel to this line connection switch 12 via a changeover switch S1, and a changeover switch S2 is connected to the other side of these amplifiers 13 and 14. Note that the amplifier 13 is connected to the terminal device 2 _-1
The amplifier 14 is connected in the direction to amplify the measurement data signal from ~2 _-o (upstream signal), and the amplifier 14 is connected in the direction to amplify the data request signal from the center device 1 (downstream signal). The amplification degrees of these amplifiers 13 and 14 are set as follows. In other words, transmission from the center device 1 to each terminal device 2 _-1 to 2 _-o is a 1-to-n communication, and conversely, transmission from each terminal device 2 _-1 to 2 _-o to the center device 1 is 1-to-n communication. 1 communication. Therefore, the amplification degree of the amplifier 13 is set to be relatively small, and the amplification degree of the amplifier 14 is set to be relatively large. Note that the amplification degree of the amplifier 14 is set depending on the number and distance of each terminal device 2 _-1 to 2 _-o . Further, the changeover switches S1 and S2 are normally connected to the amplifier 14 side. Control unit 15
receives the detection signal from the call detection circuit 11,
Each switch S1, S2 is switched to the amplifier 14 side, and the end of transmission of the data request signal and measurement data signal is detected, and each switch S1, S2 is switched to the amplifier 14 side.
It has a function to switch and control 2.

Each terminal device 2 _-1 to 2 _-o stores the measured amount at the measurement end as measurement data, and the amplification degree of these terminal devices 2 _-1 to _{2 -o} when transmitting data is different from each terminal device 2 _-1 to 2 It is set according to the distance from _-o to the relay amplification network control device 10.

Next, the operation of the system configured as described above will be explained. Each of the terminal devices 2 _-1 to 2 _-o stores measured quantities such as water level and electricity at each measuring end as measurement data. Therefore, when collecting these measurement data, the center device 1
A dial signal is sent from the relay amplification control device 10 to which the terminal devices 2 _-1 to _{2 -o} to which data should be collected are connected. The network control device 3 receives this dial signal and transmits the relay amplification network control device 1 via the exchanges 4 and 6.
0, a calling signal P as shown in FIG. 3 is sent out. Upon receiving this paging signal P, the relay amplification network control device 10 operates its paging detection circuit 11 to close the line connection switch 12 and sends a detection signal to the control section 15. Upon receiving the detection signal, the control section 15 checks whether each of the changeover switches S1 and S2 is connected to the amplifier 14 side. As a result, the center device 1 and each of the terminal devices 2 _-1 to _{2 -o} become communicable, and the relay amplification network control device 10 transmits a signal indicating that communication is possible to the center device 1.

Then, the center device 1 transmits a data request signal S including an address indicating the terminal devices 2 _-1 to _{2 -o} , for example 2 _-1 , from which data should be collected and a data request.
This signal S is sent to the relay amplification network control device 10 through the exchanges 4 and 6, amplified by the amplifier 14 of the relay amplification network control device 10, and sent to each terminal device 2 _-1 to _{2 -o.} . Each of the terminal devices 2 _-1 to 2 _-o that receives this signal S determines whether the addresses match, and only the matched terminal device 2 _-1 transmits the measurement data signal D.

By the way, when transmitting and receiving these signals S and D, the changeover switches S1 and S2 of the relay amplification network control device 10
is controlled as follows. That is, the control section 15 detects the data request signal S, and switches the changeover switches S1 and S2 to the amplifier 13 side if the level of the signal S does not fluctuate for a predetermined time _t1 or more. Then, the measurement data signal D of the terminal device _2-1 transmitted in response to this switching is transmitted to the amplifier 13.
The signal is amplified and sent to the exchange 6. As a result, the measurement data signal D is sent to the center device 1. At this time, the control unit 15 controls the measurement data signal D
, and if the level does not fluctuate for a predetermined time t ₂ or more, the changeover switches S1 and S2 are switched to the amplifier 14 side again. In this way, data collection for terminal device 2 _-1 is completed. Then,
When collecting data for another terminal device 2 _-2 to 2 _-o connected to the relay amplification network control device 10, after data collection for the terminal device 2 _-1 is completed, data is collected for the other terminal device 2 _-2 to 2 -o. 2 Data request signal S to _-o
What is necessary is to send it from the center device 1. Note that the control unit 15 monitors the signal S from the center device 1 for a predetermined time T after the transmission of the measurement data signal D is completed,
If the signal S is not detected, the line connection switch 12
A signal is sent to the call detection circuit 11 to open the circuit.

In this way, in the system of the present invention, the relay amplification network control device 10 having the amplifiers 13 and 14 is provided between the center device 1 and each terminal device 2 _-1 to 2 _-o , and data from the center device 1 is Since the request signal S is amplified and sent to each terminal device 2 _-1 to _{2 -o} , and the measurement data signal D from each terminal device 2 _-1 to 2 _-o is amplified and sent to the center device 1, Each terminal device 2
_-1 to 2 _- Even if the distance between -o and the relay amplification network control device 10 becomes long, data collection is possible. Also,
The number of terminal devices 2 _-1 to 2 _-o increases, and the level of the data request signal S sent from the relay amplification network control device 10 to each terminal device 2 _-1 to 2 _-o does not decrease. Furthermore, since the amplifiers 13 and 14 are provided for two systems, one for upstream signals and one for downstream signals, their amplification levels can be set separately depending on the installation status of the system, especially the installation status of terminal devices 2 _-1 to 2 _-o . can. Therefore, even if a large number of terminal devices 2 _-1 to 2 _-o are scattered over a long distance, data can be collected for these terminal devices 2 _-1 to _{2 -o} .

In addition, there is no need to connect a relay network control device to which one terminal device is connected to a plurality of exchanges 6 as in the conventional case, and the equipment cost corresponding to this can be reduced, making it economical.

Also, unlike the case where the relay network control device is connected to multiple exchanges 6, data collection for the terminal devices _2-1 to 2 _-o can be done by just one dialing to the relay amplification network control device 10. It's over. Therefore, data collection time is reduced.

Note that the terminal devices 2 _-1 to _{2 -o} are a mixture of those installed at long distances and those installed at short distances, and the amplification degree of 14 is higher than that for the long distance ones. Even if a relatively high level signal is input to a terminal device in a short distance after setting, the terminal device 2 _-1 to 2
The input tolerance for _-o is generally wide, so
The input signal is never clipped.

As a result of the above, measurement data can be collected at measurement terminals scattered over a wide area.

[Effects of the Invention] According to the present invention, economical data collection is possible in which long-distance transmission is possible without a drop in signal level even when a plurality of terminal devices are connected and the transmission distance becomes long, and data collection time can be shortened. system can be provided.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing an embodiment of a data collection system according to the present invention, FIG. 2 is a specific block diagram of a relay amplification network control device in the system shown in FIG. 1, and FIG. FIG. 4 is a diagram showing the operation timing of the relay amplification network control device shown in the figure, and is a configuration diagram of a conventional data collection system. 1... Center device, 2 _-1 to 2 _-o ... Terminal device, 4,
6... Switchboard, 5... Telephone line, 10... Relay amplification network control device, 11... Call detection circuit, 12... Line connection switch, 13, 14... Amplifier, 15... Control unit,
S1, S2...changeover switch.

Claims (1)

[Scope of Claims] 1. A center device, a network control device that receives a dial signal sent from the center device and sends out a paging signal, and a relay amplifier connected to the network control device via a communication line. and a plurality of terminal devices connected to the relay amplifier device by a multi-drop method and each storing measurement data, the sensor device transmits a data request signal to each of the terminal devices, and the sensor device transmits a data request signal to each of the terminal devices. The relay amplifier device has a function of collecting the measurement data sent from the communication line, and the relay amplifier device connects the line connection switch connected to the communication line and the communication line in response to the call signal transmitted through the communication line. a paging detection circuit that closes a connection switch; and a call detection circuit that is connected to the line connection switch and is set to a relatively high amplification degree according to the number of connected terminal devices and the distance from the terminal device, and the communication line is connected to the communication line. a first amplifier that amplifies the transmitted data request signal; and a second amplifier that is connected in parallel to the first amplifier and set to a relatively low amplification degree to amplify the measurement data from each terminal device. amplifier, each changeover switch commonly connected to each input/output terminal of these first and second amplifiers, and receiving a detection signal from said call detection circuit, said each changeover switch to said first amplifier side. and a control unit that detects the level of the data request signal and the measured data and controls switching of each of the changeover switches, and each of the terminal devices transmits the measured data upon receiving the data request signal. A data collection system characterized by having a function to.