JPH06164590A - Multiplex communication system - Google Patents

Abstract

PURPOSE:To easily cope with the increase or the decrease of the number or the change of the kind of terminals. CONSTITUTION:Transmission line extending means 11a, 11b write a pertinent inputted transmission data in the data tables of RAMs 15a, 15b corresponding to a correspondent address number AN respectively at a prescribed time interval concerning the input terminals 3, 4 (7, 8) from among plural terminals under their own management. On the other hand, concerning the output terminals 5, 6 (9, 10), they transmit the contents of the data tables of the RAMs 15a, 15b corresponding to the address number AN of the pertinent terminals. Besides, the transmission line extending means 11a, 11b transmit the contents of the above-mentioned data tables to the outside through MODEMs 14a, 14b at the prescribed time interval, and on the other hand, when they receive the transmit data from the other side through the MODEMs 14a, 14b, they write the pertinent transmission data in the data tables corresponding to the correspondent address number AN, and update the contents of the data tables.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a multiplex transmission system for fetching information on a production line and transmitting it to another terminal or host computer at a remote place.

[0002]

2. Description of the Related Art Conventionally, in factory automation and the like, a LAN (Local Area Network) has been used as a network for fetching data on a production line and transmitting it to other terminals or a host computer via a transmission line. . Various multiplex transmission systems composed of a plurality of terminals (input devices, output devices) are connected to the transmission lines constituting the LAN via a predetermined interface. Each terminal captures information (input device) such as on / off of a switch on the production line, or controls (turns on / off) a lamp (light output) according to the above information.
Further, since the input device and the output device are arranged in a wide range, in order to facilitate the routing of the connection cord,
They are connected by a transmission line such as two twisted pair cables (twisted pair cables) or a coaxial cable, and various data are transmitted through the transmission line by a method such as time division.

[0003]

By the way, in the above-mentioned multiplex transmission system, there is a case where data is transmitted / received to / from a terminal at a remote place, which is impossible by connection through a transmission line. In this case, in the conventional multiplex transmission system, the data of the input terminal among the terminals connected to one of the transmission lines is taken into the computer and sent to the public telephone line through the modem connected to the computer, while the other is sent. The computer on the side of the transmission path receives the transmitted data via the modem and supplies it to the output terminal among the terminals under its own control. Similarly, the data of the input terminal on the other transmission line side is also supplied by the computer to the output terminal on the one transmission line side via the public line. However, in the above-mentioned transfer process, since the computer and each terminal under its control directly exchange data, depending on the number and type (input device, output device) of terminals connected to the transmission path. Communication software needs to be created individually. Therefore, the conventional multiplex transmission system has a problem that it takes a lot of time to develop and create software.

The present invention has been made in view of the above-mentioned circumstances, and an object thereof is to provide a multiplex transmission system which can easily cope with an increase or decrease in the number of terminals and a change in type.

[0005]

In order to solve the above-mentioned problems, the present invention assigns individual addresses,
A plurality of terminals connected to at least two different multiple transmission paths, a data table corresponding to the address assigned to each of the plurality of terminals, and communication for exchanging transmission data with the outside according to a predetermined communication protocol Means for providing input data to an input terminal among the plurality of terminals under its own control at predetermined time intervals provided in each of the different multiplex transmission lines,
Write to the data table corresponding to the corresponding address, while sending the contents of the data table corresponding to the address of the terminal to the output terminal,
While transmitting the contents of the data table to the outside via the communication unit at the predetermined time interval, when the transmission data is received from the outside via the communication unit, the transmission data corresponds to the corresponding address. Transmission line extension means for writing to the data table and updating the contents is provided.

[0006]

The transmission line extension means is connected to each of different multiplex transmission lines, and the input transmission data is transmitted to the input terminal among the plurality of terminals under its control at predetermined time intervals. , Write to the data table corresponding to the corresponding address, while sending the contents of the data table corresponding to the address of the terminal to the output terminal. Further, the contents of the data table are transmitted to the outside via the communication means at a predetermined time interval. On the other hand, when transmission data is received from the outside via the communication means, the transmission data is written in the data table corresponding to the corresponding address, and the contents of the data table are updated.

[0007]

Embodiments of the present invention will now be described with reference to the drawings. FIG. 1 is a block diagram showing the configuration of an embodiment of the present invention. In the figure, 1 and 2 are transmission lines,
It consists of one twisted pair cable (twisted pair cable), coaxial cable, etc., and each has a length of 4 km. Input devices 3, 4 and output devices 5, 6 are connected to the transmission line 1, and input devices 7, 8 and output devices 9, 10 are connected to the transmission line 2. These input devices 3,
4, 7, 8 and the output devices 5, 6, 9, 10 are individually assigned with “# 1” to “# 6” as address numbers AN, and are automatically distinguished. Further, an attribute indicating whether the terminal corresponding to each address number AN is an input device or an output device is also set.

Further, 11a and 11b are transmission line extension devices, which are MPUs (microprocessor units) 12a and 12b, transmission / reception circuits 13a and 13b, modems 14a and 14b, and RAM (random access.
The memory) 15a, 15b. The transmission line extension devices 11a and 11b have the same configuration,
Also, since they have the same function, only one transmission line extension device 11a will be described. The transmission line extension device 1
In 1a, the MPU 12a controls the operation of the device. In particular, the MPU 12a controls the transmission / reception of a transmission signal between the input devices 3 and 4 and the output devices 5 and 6 via the transmission / reception circuit 13a, and the modem 14a Control data exchange. The transmission line 1 is connected to the transmission / reception circuit 13a, which transmits and receives transmission signals to and from the input devices 3 and 4 and the output devices 5 and 6, and also performs data conversion between the transmission signals and the MPU 12a.

A public line 20 is connected to the modem 14a, and a RAM 15 to be described later is used during transmission.
The contents of a are converted into voice signals and transmitted to the public line 20, while at the time of reception, the transmission signal from the other transmission line extension device 11b transmitted via the public line is received and converted into digital data. After conversion, it is supplied to the MPU 12a. Next, the RAM 15a is provided with individual data tables corresponding to the address numbers AN of the input devices 3 and 4 and the output devices 5 and 6, and once the input devices 3 and 4 are accessed via the data tables. Data is transmitted and received to and from the output devices 5 and 6.

Next, the operation of the multiplex transmission system having the above configuration will be described with reference to FIGS.
FIG. 2 is a flowchart showing a processing procedure of a main routine of the transmission line extension devices 11a and 11b. Further, FIG. 3 is a flow chart showing the details of the processing of FIG. 2, and FIG. 4 is a flow chart showing the receiving processing by the received data via the modem. In addition, both transmission line extension devices 1
In 1a and 11b, the same processing shown in FIGS. 2 to 4 is performed.

Normally, the transmission line extension devices 11a and 11b are
Each of the modems 14a and 14b is set to the automatic incoming state, and when the modem receives the transmission signal from the outside and outputs the carrier, the MPUs 12a and 12b are interrupted. On the other hand, when the carrier is not output and the interrupt is not generated, the main routine shown in FIG. 2 is repeatedly executed.

First, the operation of the transmission line extension device 11a will be described. The transmission line extension device 11a uses the step SA1.
In step 3, the data transfer process shown in FIG. 3 is performed. First, FIG.
In step SB1, the variable i representing the address number AN is set to "1". Next, in step SB2,
It is determined whether or not the terminal having the address number AN (# 1) corresponding to the variable i is the input terminal. In this example, since the terminal having the address number AN of "#i" (that is, the terminal of "# 1") is the input device 3, the determination result of the above step SB2 is "YES", and the process proceeds to step SB3. Then, in step SB3, the input device 3 whose address number AN is "# 1" is polled, the response data is received, and "#" of the RAM 15a is received by the response data.
The contents of the data table corresponding to "1" are updated.

Next, in step SB4, the variable i is incremented by "1". And step SB
Going to step 5, it is determined whether the variable i is larger than "6". In this case, since the variable i is “2”, step S
The determination result in B5 is “NO”, and step SB
Return to 2. Since the terminal having the address number AN of "#i" (that is, the terminal of "# 2") is the output device 5, the determination result of the above step SB2 is "NO", and the step S
Go to B6. In step SB6, it is determined whether or not the terminal having the address number AN (# 1) corresponding to the variable i is the output terminal. In this example, the address number AN is "#
The terminal of “i” (that is, the terminal of “# 2”) is the output device 5
Therefore, the determination result of step SB6 is “YE
S ”, and the process proceeds to step SB7. Then, in step SB7, the contents of the data table corresponding to "# 2" of the RAM 15a are sent to the input device 5 whose address number AN is "# 2". Hereinafter, steps SB4 and S
The process proceeds to B5, the variable i is incremented, and steps SB2 to SB7 are repeatedly executed again.

On the other hand, when the result of the judgment in step SB6 is "NO", the variable i is updated without operating the data table of the RAM 15a, and the input terminal or output terminal corresponding to the next address number AN. Is processed. When the variable i becomes larger than “6” in step SB4 described above, the determination result of step SB5 becomes “YES”, the data transfer process ends, and the process returns to the main routine shown in FIG.

In the main routine shown in FIG. 2, the process proceeds to step SA2, and the contents of the data table in the RAM 15a updated in step SA1 (corresponding to the input devices 3 and 4) are transferred to the other transmission line via the modem 14a. It transmits to the extension device 11b.

In the transmission line extension device 11b, the modem 14b receives the transmission signal and outputs the carrier by the transmission processing in step SA2 of the transmission line extension device 11a, so that the MPU 12b is interrupted. MP
The U 12b suspends the process (for example, the data transfer process) that has been executed until immediately before the interrupt is taken, and executes the reception process shown in FIG. That is, in step SC1, the transmission data is received via the modem 14b, and in step SC3, the address number AN of the transmission data is received.
The contents of the data table corresponding to are updated by the transmission data. In this example, the address number AN is "#
The contents of the data table corresponding to "1" and "# 3" are updated. When the reception process is completed, the process temporarily returns to the suspended process.

As described above, the flowcharts shown in FIGS. 2 to 4 are also executed in the transmission line extension device 11b. Therefore, in the transmission line extension device 11b,
Normally, the flowcharts shown in FIGS. 2 and 3 are executed. That is, in step SB3 of FIG. 3, the data table in the RAM 15b is updated by the response data of the input terminals 7 and 8 having the address numbers AN of "# 4" and "# 5", and the address number AN in the RAM 15b is updated.
The contents of the data tables of "# 3" and "# 6" are sent to the output terminals 9 and 10. Then, when the processing shown in FIG. 3 is completed, in step SA2, the above step S
Updated in A1 (corresponding to the input device 7, 8),
The contents of the data table in the RAM 15b are stored in the modem 14b.
Is transmitted to the transmission line extension device 11a via.

In the transmission path extension device 11a, the modem 14a receives the transmission signal and outputs the carrier by the transmission processing in step SA2 of the transmission path extension device 11b, so that the MPU 12a is interrupted. MP
The U 12a temporarily suspends the process that was being executed immediately before the interrupt was taken, and executes the receiving process shown in FIG. 4 as described above. As a result, the address numbers AN are "# 4" and "# 5".
The contents of the data table corresponding to are updated.

Since the above processing is performed at a predetermined time interval, the RAM 15 of each transmission line extension device 11a, 11b.
The contents of the data tables in a and 15b are updated at the above predetermined time intervals. In addition, each transmission line extension device 11a, 1
1b updates the data table each time the other party transmits data, so the data is always new.
Further, even if the number of input devices or output devices is increased or decreased, it is only necessary to increase or decrease the data table, so that the configuration can be easily changed. In addition, even if the type of terminal is changed, it can be handled simply by changing the input / output attributes.

In the above-described embodiment, the data is transmitted and received via the public line, but the present invention is not limited to this, and wireless communication, optical communication or the like may be used depending on the installation conditions of the multiplex transmission system. . In this case, the modems 14a, 14
b is provided with a means corresponding to the communication method.

[0021]

As described above, according to the present invention, the plurality of terminals under the control of themselves by the transmission line extending means connected to the different multiple transmission lines at predetermined time intervals. For the input terminal, the input transmission data is written in the data table corresponding to the corresponding address, while for the output terminal, the content of the data table corresponding to the address of the terminal. And transmitting the contents of the data table to the outside via the communication means at a predetermined time interval, while receiving the transmission data from the outside via the communication means, the transmission data Since the data table corresponding to the address to be written is written and the contents of the data table are updated, it is possible to easily cope with an increase or decrease in the number of terminals and a change in type. It is obtained.

[Brief description of drawings]

FIG. 1 is a block diagram showing the configuration of an embodiment of the present invention.

FIG. 2 is a flowchart showing a processing procedure of the transmission line extension device of the embodiment.

3 is a flowchart showing a detailed processing procedure of the data transfer processing of FIG.

FIG. 4 is a flowchart showing a reception processing procedure of the transmission path extension apparatus of the embodiment.

[Explanation of symbols]

 1, 2 Transmission line (multiplex transmission line) 3, 4, 7, 8 Input device (terminal) 5, 6, 9, 10 Output device (terminal) 11a, 11b Transmission line extension device (transmission line extension means) 14a, 14b Modem (communication means) 15a, 15b RAM (data table) AN address number (address)

Claims (1)

[Claims] 1. A plurality of terminals to which individual addresses are attached and which are connected to any one of at least two different multiplex transmission lines, a data table corresponding to the addresses attached to each of the plurality of terminals, and a predetermined number. Of the plurality of terminals under the control of itself, which are provided in each of the different multiplex transmission paths and which have communication means for exchanging transmission data with the outside according to the communication protocol of For the input transmission data is written in the data table corresponding to the corresponding address, while, to the output terminal, while transmitting the contents of the data table corresponding to the address of the terminal, At the predetermined time interval, the contents of the data table are transmitted to the outside via the communication means, while the transmission data is transmitted from the outside via the communication means. Upon receiving the transmission data, the transmission data is written in the data table corresponding to the corresponding address and the contents are updated, and a transmission line extension means is provided.