JPS5950633A - Loop type data highway system by optical communication - Google Patents

Abstract

PURPOSE:To improve the noise resistance and to release the limit of the number of relay devices and transmission distance, by constituting a transmission line with an optical fiber cable and a data station with an optical transmitter/ receiver. CONSTITUTION:Data on transmission lines L'1 and L'2 is photoelectrically converted by an optical receiver (a), and the data and a clock are produced by regenerative relay devices c, d. The regenerated data is transmitted on the transmission line via an optical transmitter (b) and to a disconnection detection and data clock switching circuit (e) together with the clock. The disconnection detection and data clock switching circuit (e) monitors the transmission lines L'1, L'2 and transmits/receives the data and clock between a serial/parallel converting circuit (f) and the regenerative relay devices (c), (d).

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a data highway system using optical communication.

FIG. 1 (4) shows a schematic configuration of the loop data highway system. In the figure, MS is a master station, R81, R82, . . . , R8N are remote stations, L1 is a 1-system transmission line, and L2 is a 2-system transmission line. Traditionally, in modern loop data highway systems, electric wires have been used as transmission paths. however,
When using the electric wire #J, there was a limit to the noise resistance. In addition, in a loop data highway system that uses optical communications, an optical switch is installed at each station to shut off the power.

Backup was performed in case of a situation equivalent to a disconnection due to a transmitter/receiver failure, that is, a station down. However, when an optical switch is used to back up a station down, there are the following problems. For example, if data station DSi-+-+ goes down in FIG.
What is the transmission distance between /? 1+i2, which limits the transmission distance of the entire system and limits the number of relays (number of stations).

The present invention has been elaborated in view of the above points and improves noise resistance! A loop-type data highway system using optical communication that does not limit the number of repeaters or transmission distance. Our purpose and purpose is to provide.

In order to achieve this purpose in the present invention, each transmission path? It is characterized in that it is constructed from an optical fiber cable, and the transmitter/receiver of each data station is constructed from an optical transmitter/receiver.

An embodiment of the present invention will be described below with reference to the attached drawings.

FIG. 2 is a block diagram of an embodiment of a loop type data highway system using optical communication according to the present invention. M.S.
'Master station R3I', R82'...
R13N' is a remote station, and the transceiver built into this station is constituted by an optical transceiver, as will be described later. Also, L' + 1 L'
Reference numeral 2 denotes a system transmission line and a system transmission line 2, respectively, which are constructed of optical fiber cables. The details of each data station will be explained with reference to FIG. In the figure, a is an optical receiver, h is an optical transmitter, and c&'! , 1-system regenerative repeater ij%, d is a 2-system regenerative repeater, e is a disconnection detection and data clock switching circuit, f is a serial-to-parallel converter circuit 1g is a transmitting/receiving buffer and a transmission control unit that performs M:N data conversion by loop transmission. The implementation protocol and error control are being carried out. h is CP
This is an interface for connecting to U bus j. 1 series,
The data from the transmission line Ll' + L2' of the 2nd system is optical-to-electrically converted by the optical receiver a.The data and clock are generated by the regenerative repeater cod of the 1st and 2nd systems. The generated data is sent to the transmission line via the optical transmitter b7, and is also sent together with a clock to the disconnection detection and data clock switching circuit e.In the disconnection detection and data clock switching circuit θ, the 1st system, 2-system transmission line L1'.

monitoring of L, /, and serial/parallel conversion circuit f and regenerative repeater c,
Data and clocks are exchanged between d and d.

One embodiment of the present invention is constructed as described above, and the kettle station during normal operation is connected to the transmission line of system 1, '?', as shown in FIG. The master station MS is used to send and receive data, and only the data from the master station MS is flowing through the transmission path L2/ of the second system.

Next, a backup method for station down will be explained with reference to FIGS. 3 and 5. For example, if remote station R82' goes down, remote stations R8I' and R
At step 83', disconnection of the abnormal transmission line is detected, and a loopback configuration is taken as already proposed by the present applicant in Japanese Patent Application No. 56-92485. That is, remote station RB
1', disconnection detection and data/clock switching circuit e
The disconnection of the abnormal transmission line is detected based on the transmission and reception data from the regenerative repeaters c and d.
A loopback configuration is established by switching the connection to the 2nd system transmission line L2/. Similarly, at the remote station R83', the disconnection detection and data/clock switching circuit e detects the disconnection of the abnormal transmission line, and, for example, connects the 2nd system transmission line L27 to the 1st system transmission line L1/ to configure a loopback. Ketoru. At this time, Master Station MS'&'! After confirming that the 1st system disconnection information from each remote station R81' and RBg' and the 2nd system reception of the own station are OK, the 2nd system reception is bypassed to the 2nd system transmission, and one closed loop is established for the entire system. Make sure it's configured.

In this way, the transmission function of the entire system can be continued.

Next, disconnection in the transmission line will be explained with reference to FIG. For example, remote stations R8I' and R8
2', the stations R8I' and R82' on both sides of the disconnection will each have a loopback configuration 'IX', similar to the case of station down in Figure 5. r, master station M8'
However, it is possible to continue the transmission function by bypassing the 2nd system reception to the 2nd system transmission and constructing one closed loop for the entire system.

One embodiment of the present invention is as described above and has the following effects.

(1) Since an optical fiber cable is used for the transmission line, noise resistance performance is improved.

(Backup for 21 stations going down is achieved by configuring a loopback at the stations on both sides of the station that went down, instead of using an optical switch as in the conventional loop data highway system using optical communication.) There is no extension of transmission distance due to station bypass when using a switch, and the number of relays (
(number of stations) and transmission distance.

(3) Is there backup in case of a break in the optical fiber cable that makes up the transmission line by looping back at stations on both sides of the break? This can be done by configuring.

(4) From the above, loop type data p using optical communication
Improving reliability when implementing highway systems! It can be measured.

As described above, the present invention realizes a loop-type data highway system using optical communication that has high noise resistance and does not affect the number of repeaters or transmission distance.

[Brief explanation of drawings]

Figure 1 is a block diagram showing the schematic configuration of a conventional loop-type data highway system;
2 is a block diagram illustrating a backup method for station down using an optical switch, FIG. 2 is a block diagram showing a schematic configuration of a loop data highway system using optical communication according to the present invention, and FIG. 3 is shown in @2. FIG. 4 is a block diagram showing the internal configuration of the station in which data is stored normally. FIG.
The block diagram to explain the flow of data when the station is down in Figure 6 is the flow of data when the transmission line is disconnected. FIG. 2 is a block diagram for explanation. ME! '...Master station, R8I',
R32'...R8N'...Remote station,
L12...1 system FI transmission line, L2/...2 system transmission line. 512LI 52 DSi DSi++ DSi
+2178-

Claims (1)

[Claims] 11) In a loop-type data highway system in which a plurality of data stations are connected to each other by dual transmission paths having different transmission directions. Each transmission line is configured with an optical fiber cable, and the transmitter/receiver of each data station is configured with an optical transmitter/receiver. The built-in disconnection detection function automatically detects disconnections and creates a loopback configuration depending on the disconnection situation. A loop-type data highway system using optical communications that enables continuity of transmission functions by