JPS63292742A - Line switching system for loop type data transmission line - Google Patents

Abstract

PURPOSE:To obtain a high reliability loop data transmission line by dividing an operating system transmission line into a main and a sub lines so as to constitute a triple loop transmission line including a loopback system transmission line. CONSTITUTION:The titled system is provided with input data fault discrimination circuits 9, 10, 11 connected respectively to the transmission lines of the main operating system (a), the sub operating system (b), and the loopback system (c), circuits 12, 13, 15 using a system having a normal input data in either the main operating system or the sub operating system as the input transmission line and outputting the same data to both the main and sub operating system at the output side, and a circuit 16 using the loopback system when the main and sub operating systems discriminate the input data as an error to stop the output of the loopback system. Moreover, a circuit 14 branching either the main or the sub operating system whose input data is discriminated for the normality by the loopback system at the discrimination of an input data error as the input transmission line, is provided. Thus, even if an error of two or more operating lines takes place, either of the main and sub systems can be operated.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a loop data transmission system, and more particularly to a line switching system for a data transmission path in the event of a failure.

(Prior art) Conventionally, this type of line switching system has duplicated loop-shaped transmission lines, one of which is used as an active system and the other as a loopback system, which are connected in opposite directions.During normal times, data is transmitted using the active system. When an error is detected in the input data of the active system, the output of the loopback system is stopped using the loopback system as the input transmission path, and when an error is detected in the input data of the loopback system, the output is branched using the active system as the input transmission path. was.

FIG. 4 is a system configuration diagram of a conventional loop data transmission line. Each of the data transmission devices 5 to 8 connects an active transmission line and a loopback transmission line C in opposite directions to form a loop data transmission line. As shown in FIG. 5, when a transmission line failure occurs on the active transmission line, the data transmission device 7 determines that the input data to the active transmission line is abnormal and changes the input data to the loopback transmission line C. ′
At the same time as switching the line to the transmission line, output to the loopback system transmission line C is stopped. The data transmission device 6 determines an abnormality in the input data of the loopback system transmission path C by stopping the output of the data transmission device 7 to the loopback system transmission path C, and transmits the output data to the active system transmission path. C
The line will be switched so that the output will also be branched to. In this way, the loop data transmission line is maintained normally through the above-mentioned and cover operations.

- (Problems to be solved by the invention) The conventional line switching method described above is a loopback method in which when a failure occurs in the active transmission line, the loopback transmission line is immediately used to bypass the failure. Since loopback operation is performed between the front and rear data transmission devices, if a failure occurs in two or more locations on the active transmission path, the data transmission device between the failure locations will be disconnected from the transmission path. The drawback was that line outages due to failures increased, and in the worst case, all lines were stopped.

To explain a specific example with reference to FIG. 6, there are two transmission line breaks in the active transmission line: 1. If j occurs, the data transmission device 7 stops outputting data to the loopback system transmission path C due to the transmission path disconnection i, and the data transmission device 5 stops outputting data to the loopback system transmission path C due to the transmission path disconnection i. Stop output. Therefore, data transmission is impossible at two locations, one between the data transmission devices 6.7 and the other between the data transmission devices 5.8, and when the data transmission device 5 is a system mask of this loop data transmission path, the data transmission device 7 8 is isolated from the loop data transmission path and cannot communicate. In other words, the loop data transmission path is operated in a reduced form with two stations of data transmission equipment 5 and 6, and it is impossible to maintain a complete system with four stations of data transmission equipment 5 to 8. There is.

(Means for Solving the Problems) In the loop data transmission line switching system of the present invention, a plurality of data transmission devices are connected by a triplex loop-shaped transmission line of a primary operation system, a sub-operation system, and a loopback system. In a loop-type data transmission path where the primary and secondary systems are connected in the same direction and the loopback system is connected in the opposite direction, input data that is connected to the primary, secondary, and loopback transmission paths, respectively. An abnormality judgment circuit, a circuit that uses either the main operating system or the sub-operating system with normal human input data as the human-powered transmission path, and a circuit that outputs the same data to both the main operating system and the sub-operating system on the output side. A circuit that uses the loopback system as an input transmission path and stops the output of the loopback system when the active system and the sub-active system determine that the input data is abnormal, and a circuit that determines whether the loopback system is the main operating system or the sub-active system when the input data is determined to be abnormal. The input data is determined to be normal, and the selected one is used as the input transmission path and branched.

(Example) Next, the present invention will be described with reference to the drawings.

FIG. 1 is a system configuration diagram showing one embodiment of the present invention. In FIG. 1, four data transmission devices 1 to 4 are connected by a primary transmission line a, a secondary transmission line, and a loopback transmission line C to form a loop data transmission line. Data transmission devices 1 to 4 are normally operating transmission lines a
is used as the input transmission line, and the same data is sent to the primary operation transmission line a and the sub-operation transmission line A. In addition, the data transmission device 1
4 performs relay transmission on the loopback system transmission line C.

FIG. 2 is a block diagram showing the internal configuration of data transmission devices 1 to 4 shown in FIG. 1. The line switching circuit 12 switches the input transmission line from the main transmission line a to the sub-operation transmission line in response to an alarm signal indicating input data abnormality from the input data abnormality determination circuit 9 of the main transmission line a. In addition, the line switching circuit 13 includes a manual data abnormality determination circuit 9 for the primary operation transmission line a and an input data abnormality determination circuit 1 for the sub-operation transmission line a.
The input transmission line is switched from the output data of the line switching circuit 12 to the loopback system transmission line C in response to two alarm signals indicating an abnormality in the input data from the data branching/insertion circuit 1.
5. Manually input the data. Output data 15' of the data drop/add circuit 15 is sent to the primary active transmission line a and the secondary active transmission line a.

The line switching circuit 14 switches the line from the loopback transmission line C to the output data of the data drop/add circuit 15 in response to an alarm signal indicating input data abnormality from the input data abnormality determination circuit 11 of the loopback transmission line C. The output data 14° of the line switching circuit 14 passes through the output stop circuit 16, and when there are two alarm signals indicating input data abnormality from the input data abnormality judgment circuit 9 and the input data abnormality judgment circuit IO, the output data loops. Sending to the back system transmission line C is stopped.

FIG. 3 is a diagram showing an example of the operation of the line switching system of the loop data transmission line shown in FIG. 1. When the transmission line d of the main operation system transmission line a is disconnected, the data transmission device 3 determines that the manual data from the main operation system transmission line a is abnormal, sets the sub-operation system transmission line A as the manual transmission line, and the output side becomes the main operation system transmission line. The same data is sent to the transmission path a and the sub-active system transmission path. In addition, when the transmission line e of the sub-operating system transmission line A is disconnected, the data transmission device 4 maintains the primary operating system transmission line a as the input transmission line without switching the line. Furthermore, if the transmission line disconnection f2g of the primary operating system transmission line a and the secondary operating system transmission line 2 occurs simultaneously, the data transmission device 1 determines that the input data from the primary operating system transmission line a and the secondary operating system transmission line 2 is abnormal. Then, the loopback system transmission line C is set as the input transmission line, and data transmission through the loopback system transmission line C is stopped. At this time, the data transmission device 4 determines that the input data of the loopback transmission line C is abnormal, and also transfers the data output to the primary operation transmission line a and the sub-operation transmission line C to the loopback transmission line C. Branch and send. That is, this system has one or two standby transmission lines.

(Effects of the Invention) As explained above, the present invention has two primary and secondary transmission lines.
By configuring a triplexed loop transmission line including a loopback transmission line, one line is always on standby even when the line is operating in recovery mode due to loopback, and two or more This has the effect of providing a high-reliability loop-type data transmission line in which even if a failure occurs in the operating line, either the primary or secondary line remains operational and the operating status of the line is maintained.

[Brief explanation of the drawing]

FIG. 1 is a system configuration diagram of a loop data transmission line according to an embodiment of the present invention, FIG. 2 is a block diagram showing the internal configuration of a data transmission device according to the present invention, and FIG. 3 is a loop diagram according to an embodiment of the present invention. Figure 4 is a system configuration diagram of a conventional loop data transmission line, and Figure 5 is a diagram showing an example of loopback operation of a conventional loop data transmission line. , FIG. 6 is a diagram showing an example of a loopback operation when a double failure occurs in a conventional loop data transmission line. 1-8...Data transmission device, 9-11...Input data abnormality determination circuit, 12-14.
... Line switching circuit, 15... Data branch/insertion circuit, 16... Output stop circuit, a... Main operation system transmission line, b... Sub-operation system transmission line, C... Loopback system Transmission line, dj...Transmission line disconnected, k...Operational transmission line. Agent Patent Attorney Toshikichi Somekawa Figure 1 U, Q
. Figure 3 Figure 4 Figure 5

Claims (1)

[Claims] A loop in which multiple data transmission devices are connected by a triplexed loop-shaped transmission path of the primary operating system, secondary operating system, and loopback system, with the primary operating system and secondary operating system connected in the same direction, and the loopback system connected in the opposite direction. In the data transmission path, an input data abnormality judgment circuit is connected to each of the transmission paths of the primary operation system, the secondary operation system, and the loopback system, and the input data is determined to be normal in either the primary operation system or the secondary operation system. There is a circuit on the output side that serves as an input transmission path and outputs the same data to both the primary and secondary systems, and a loopback system that uses the loopback system as an input transmission path when the primary and secondary systems determine whether there is an error in the input data. and a circuit that, when the loopback system determines that the input data is abnormal, determines that the input data is normal in either the main operation system or the sub-operation system, and branches to the selected one as the input transmission path. A line switching method for a loop data transmission path characterized by: