JPS6149864B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a terminal device calling method for collecting data from a plurality of terminal devices.

When attempting to centrally monitor water levels, flow rates, or water quality at multiple points on a river, calls are made to terminal devices installed in advance at each point on the river, and each point is sent to a central device that centrally manages data. data will be collected.

Such data collection and management from multiple locations is performed in a variety of 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 measuring point of mechanical equipment. It is being said.

There are various methods for collecting data. The most fundamental system is one in which each terminal device and the central device are connected by separate lines, and the central device calls each terminal device as necessary to send data. However, according to this method, as the number of terminal devices increases, the number of lines increases proportionally, and large-scale cable installation may be required. Furthermore, on the side of the central device that collects data, the number of terminals connected to each terminal device increases, making the device larger, and the selection circuit for selecting a specific terminal becomes more complex.

For this reason, a system has been adopted in which a common line is used to connect the central device and each terminal device. In this method, a plurality of terminal devices are connected to a common line, so it is necessary to sequentially transmit data from these terminal devices to avoid duplication. Therefore, in the past, a method has been used in which each terminal device is provided with a different address, and the central device sequentially polls the address of each terminal device to sequentially transmit data.

However, according to such a paging system, it is necessary to sequentially send a paging signal including an address from the central device, which has the disadvantage that the central device becomes complicated in this respect. In addition, since the address is different for each terminal device, it is necessary to set a different address for each terminal device, and there is also the disadvantage that the workability becomes poor especially when setting the address on site.

The present invention has been made in view of the above-mentioned circumstances, and it is an object of the present invention to provide a terminal device paging method that can sequentially send data from one line to a central device without setting an address for each terminal. purpose.

In the present invention, a plurality of terminal devices having the same configuration are connected in series via a switch circuit within each device, and the first terminal device is connected to the central device. In the initial state, the switch circuit electrically disconnects the terminal device connected to the next stage from the central device, and connects its own terminal device from the previous terminal device (the central device in the case of the first stage terminal device). When the call signal is transmitted, the data is transmitted to the central unit through the transmission path. When the data transmission is completed, a switch is switched to electrically connect the next terminal device and the central device, and the data from each terminal device is sequentially sent to the central device, thereby achieving the above-mentioned purpose.

The present invention will be explained in detail with reference to Examples below.

FIG. 1 shows a data collection system according to an embodiment of the present invention, in which a central device 1 is provided, for example, in an instrument central control room of an apartment complex (not shown), and each terminal device 2A, 2B, . . . Similarly, each home in the apartment complex (not shown) has one installed. The terminal devices 2A, 2B, . . . all have the same configuration, and include a switch circuit 4 for switching the line 3,
A detection circuit 5 detects a call signal transmitted from the central device 1 via the switch circuit 4, and an encoder that is activated by the detection operation of the detection circuit 5 and encodes and sends data indicated by a data source 6 such as a gas meter. 7. The switch control circuit 8 detects the end of data transmission from the encoder 7 and switches the connection of the switch circuit 4.

The central device 1 that collects data and displays it is
It is connected by a line 3 to an input terminal 4A of a switch circuit 4 in the first terminal device 2A. The first output terminal 4B in the switch circuit 4, which is cut off from the input terminal 4A in the initial state, is connected by the line 3 to the input terminal 4A of the switch circuit 4 in the second terminal device 2B. The same applies to the other subsequent terminal devices 2C, 2D, . . . .

In each terminal device, the second output terminal 4C in the switch circuit 4 is connected to the detection circuit 5. This output terminal 4C is the input terminal 4A in the initial state.
is electrically connected. Therefore, as shown in FIG. 2a, when a calling signal consisting of a DC voltage is applied from the central device 1 to the line 3 at time _t0 , the detection circuit 5 in the first terminal device 2A receives this calling signal. Detect. As a result, the detection circuit 5 issues an activation signal as shown in FIG. _2b1 , and activates the encoder 7. Then, the data content indicated by the data source 6A connected to the first terminal device 2A is binarized by the encoder 7 and sent to the line 3 via the switch circuit 4.

The data sent from this first terminal device 2A is shown as "data 1" in FIG. 2 _C1 .
Therefore, as shown in Figure a, the signal appearing on the line 3 connected to the central device is a continuously applied DC voltage signal from time t ₀ until "data 1" is sent. While "data 1" is being sent, the data signal is in a binary state.
The central device 1 recognizes such a binary signal appearing on the line 3 as data of the first terminal device, decodes the data using a decoder (not shown), and displays or records the data.

When the data transmission from the encoder 7 of the first terminal device 2A is completed, this encoder 7 transmits the data to the second terminal device 2A.
Outputs a pulse-shaped data end signal as shown in Figure _d1 . The data end signal is input to the switch control circuit 8, and based on this, the switch control circuit 8
A switch circuit drive signal as shown in FIG. 2 _e1 is output to the switch circuit 4.

The switch circuit 4 in the first terminal device 2A electrically connects the input terminal 4A and the first output terminal 4B while this switch circuit drive signal is being input. That is, the calling signal sent from the central device 1 is transmitted to the input terminal 4A of the switch circuit 4 in the second terminal device 2B via the switch circuit 4 in the first terminal device 2A.

In this state, the switch circuit 4 in the second terminal device 2B, which has the same configuration as the first terminal device 2A, maintains its initial state.

Therefore, the detection circuit 5 in the second terminal device 2B detects the calling signal and outputs an activation signal as shown in FIG. _2b2 , just as in the case of the first terminal device 2A. As a result, the data content of the data source 6B directly connected to the second terminal device 2B is changed to C ₂ in FIG.
The signal is output to the line 3 by the encoder 7 as shown in FIG. Upon completion of data transmission, the encoder 7 outputs a data end signal shown in _d2 of the figure, and the switch control circuit 8 outputs a switch circuit drive signal as shown in _e2 of the figure. As a result of kneading, the switch circuit 4 of the second terminal device 2B is also switched, and the calling signal is transmitted to the third terminal device.

In this way, the calling signal is sequentially transmitted to each terminal device, and data is sequentially output to the line 3 in response. In this way, the central device 1 sequentially connects the line 3
Recognize, display, or record the data that appears on the screen.

When all n terminal devices have finished outputting data, the central device recognizes this and outputs a return signal to the line 3. This return signal is a signal in which no DC voltage is applied, as shown after time _t1 in FIG. 2a. A signal 9 for inputting this return signal to the switch control circuit 8 is connected to the input terminal 4A of each terminal device. Therefore, when a return signal is output from the central device 1 to the line 3, the return signal is input to the switch control circuit 8 in each terminal device, thereby restoring each switch circuit 4 to its initial state. That is, when a call signal is output from the central device from now on, preparations are made for data to be sequentially output from the first terminal device 2A again.

As described above, according to the present invention, the calling signal used to call each terminal device may be a simple signal such as a DC voltage applied for a predetermined period of time, and moreover, it is possible to use a common calling signal for each terminal device. This eliminates the need to make adjustments for each terminal device on site.
Excellent workability. Furthermore, since a large number of terminal devices can be installed simply by connecting them in series, the terminal devices are highly expandable.

Note that the central device of the present invention is not limited to collecting and displaying data as shown in the embodiments, but can also be provided with a function of connecting to a telephone line and transmitting data to a central information management center. In other words, for example, a central device installed in each housing complex, factory, or individual residence sends water meter data, etc., to a central information management center, which centrally manages this data, and allows water conduction to be carried out individually. The present invention can also be used as part of a system for charging fees and the like. In such a case, according to the present invention, when a data call is made from the central information management center to each central device through the subscriber telephone line, the central device can quickly access the data without specifying an address for each terminal device. A call can be made and the data immediately sent to a central information management center. That is, the present invention has important significance in such an automatic meter reading system as well in terms of reducing telephone charges and the like.

[Brief explanation of the drawing]

The drawings are for explaining one embodiment of the present invention. Fig. 1 is a block diagram of a system for collecting data, and Fig. 2 is a signal diagram for explaining the operation of each part shown in Fig. 1. FIG. 1...Central device, 2...Terminal device, 3...Line, 4...
Switch circuit, 5... Detection circuit, 6... Data source, 7
...encoder.

Claims (1)

[Claims] 1. The central device sends a calling signal to the track, collects a predetermined amount of data from a plurality of terminal devices sequentially connected to the track, and then sends a return signal to the track, and each of the terminal devices A detection circuit that detects a calling signal, an encoder that is activated by the detection operation of the detection circuit and sends the data content indicated by the data source to the line, and a terminal that disconnects the line from its own detection circuit when the encoder completes data sending. It is equipped with a switch circuit that connects to the device and that returns with a return signal from the central device and connects the line to its own detection circuit, so that each terminal device is sequentially called by a common calling signal sent from the central device. A terminal device paging method characterized by: