JP2003087280A - Ring type optical communication system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a ring type optical communication system which keeps data transmission even when an abnormality occurs in one of optical transmission lines forming a network. SOLUTION: One of nodes 2a-2d is adopted as a master station and the others are slave stations. When the abnormality occurs in one of the optical transmission lines 3a-3d connecting the nodes 2a-2d, bi-directional data transmission is performed between the master station and the slave stations through the use of a route at the opposite side of the optical transmission line with the abnormality, which connects the nodes being the both ends of the optical transmission line with the abnormality. Thus, correspondence is conducted with respect to a case when the abnormality occurs in the optical transmission line without using a restoration communication line.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a ring type optical communication system for connecting a plurality of nodes (communication stations) in a ring shape using an optical transmission line to perform data communication between the nodes, and more particularly, The present invention relates to a technique for ensuring communication between nodes even when an abnormality occurs in an optical transmission line.

[0002]

2. Description of the Related Art In recent years, vehicles such as passenger cars and one-box cars are equipped with audio equipment, navigation systems, etc.
A wide variety of devices are often installed. For example, as audio equipment, a CD player, M
A D player, a DVD player, etc. may be mounted, and a plurality of amplifiers, speakers, monitors, etc. may be mounted.

As described above, when a large number of devices are mounted in a vehicle, it is necessary to electrically connect the devices to each other, and such electrical connection becomes extremely complicated. (1), a network system is constructed in a vehicle and various devices are connected to the network system to simplify the connection of various devices.

By using the network system, for example, the navigation image data obtained by the navigation system can be transmitted to the monitor via the signal transmission path and displayed on the screen of the monitor.

FIG. 8 is an explanatory diagram showing a configuration of a conventional example of a ring type optical communication system used in a network system. As shown in FIG. 8, the ring type optical communication system 101 includes a plurality of nodes ( Each node 102 is connected in a ring shape via an optical transmission path 103 formed of an optical fiber. And
Data is transmitted between the nodes 102 by optical signals.

Here, in the optical transmission line 103 connecting the nodes 102, an abnormality such as breakage may occur and the optical signal may be interrupted. In this case, the optical communication between the nodes 102 is performed. Will not be possible. In order to solve such a problem, in the conventional ring-type optical communication system 101, each node 1
In order to secure the data transmission between the two, the recovery communication line L connecting the node serving as the master station and the node serving as the slave station is arranged as shown in FIG. When an abnormality occurs in 103, the communication line L for restoration is used to maintain the communication between the master station and the slave station.

[0007]

However, in the conventional ring type optical communication system 101, since the recovery communication line L is provided, an extra cable is required, the number of cables is increased, and the cost is increased. There was a problem.

The present invention has been made in order to solve such a conventional problem, and an object thereof is to provide an optical transmission line when an abnormality occurs without providing a restoration communication line. An object is to provide a ring type optical communication system capable of maintaining communication.

[0009]

In order to achieve the above object, the invention according to claim 1 of the present application has a plurality of communication stations, and the communication stations are connected in a ring shape using an optical transmission line. In a ring type optical communication system for performing data transmission between communication stations, one communication station among the communication stations is a master station and the other communication station is a slave station, and the communication stations are connected to each other. When an abnormality occurs in any one of the optical transmission lines among the optical transmission lines that A feature is that bidirectional data transmission between the master station and the slave station is performed using a path on the side opposite to the transmission path.

The invention according to a second aspect is a ring type optical apparatus having a plurality of communication stations, and connecting the communication stations in a ring shape by using an optical transmission line to perform data transmission between the communication stations. In the communication system, one of the communication stations is a master station, and the other communication station is a slave station. Among the optical transmission lines connecting the communication stations, optical transmission between slave stations. When an abnormality occurs in the path, the slave stations arranged on both sides of the optical transmission path in which the abnormality has occurred are on the opposite side of the optical transmission path in which the abnormality has occurred, and When bi-directional data transmission is performed with the master station and an abnormality occurs in the optical transmission line between the master station and the slave station among the optical transmission lines connecting the communication stations, , A slave station arranged on one end side of the optical transmission line where the abnormality has occurred, and the other end And a master station which is arranged, said abnormal optical transmission line has occurred in the path on the opposite side, and performs bidirectional data transmission between each slave station and the master station.

According to a third aspect of the present invention, there is provided a ring type optical fiber having a plurality of communication stations, and connecting the communication stations in a ring shape using an optical transmission line to perform data transmission between the communication stations. In the communication system, one of the communication stations is a master station and the other communication station is a slave station, and each communication station is formed in a ring shape with control means for controlling the communication station. A communication IC for controlling transmission / reception of an optical signal using the optical transmission line, first photoelectric conversion means for converting an electric signal to be transmitted into an optical signal, and converting a received optical signal into an electric signal, and a second Photoelectric conversion means, the first photoelectric conversion means, the second photoelectric conversion means, and switching means for switching the connection with the communication IC or the control means, the control means of each communication station When there is no abnormality in the optical transmission line, Wherein the signal IC first photoelectric conversion means,
And the switching means is controlled so as to be connected to the optical transmission path via the second photoelectric conversion means, and any one of the optical transmission paths arranged between the communication stations is abnormal. When the error occurs, the switching means is controlled so that the control means of the slave station and the control means of the master station are connected using an optical transmission line other than the optical transmission line in which the abnormality has occurred. It is characterized by doing.

According to a fourth aspect of the present invention, each of the first photoelectric conversion means and the second photoelectric conversion means includes a reception photoelectric conversion element and a transmission photoelectric conversion element, and the optical transmission line is provided. When an abnormality occurs in the, the mode for transmitting data from the master station to the slave station by switching the connection with the control means to either the reception photoelectric conversion element or the transmission photoelectric conversion element. And a mode for transmitting data from the slave station to the master station is switched.

According to a fifth aspect of the present invention, the master station is changed to a temporary slave station when an abnormality occurs in any one of the optical transmission paths among the communication stations. Then
And each slave station is changed to a temporary master station, each temporary master station, while sending an optical signal to the optical transmission path,
The provisional master station determines whether or not an optical signal is received from the provisional master station on the upstream side of the optical transmission path,
It is characterized in that the upstream optical transmission line of the temporary master station, which is determined not to receive the optical signal, is determined to be the optical transmission line in which the abnormality has occurred.

The invention according to a sixth aspect is characterized in that the ring type optical communication system is mounted in a vehicle.

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is an explanatory diagram showing a configuration of a ring type optical communication system according to an embodiment of the present invention. As shown in the figure, the ring type optical communication system 1 includes a plurality of (4 in the figure) Nodes 2a to 2d, each node 2
Rings a to 2d are connected by an optical transmission line 3 (3a to 3d). The ring type optical communication system 1 is used as a network system mounted in a vehicle such as a passenger car or a one-box car. As the nodes 2a to 2d, for example, a navigation system, a DVD player, or a monitor device is used. Can be mentioned.

The node 2a shown in FIG. 1 is a master station which controls the entire system as a whole, and the other nodes 2a.
b, 2c and 2d are slave stations that operate under the control of the master station.

FIG. 2 shows a detailed configuration of the node 2a serving as a master station and the node 2b serving as a slave station (here, the configuration of the node 2b is shown, but 2c and 2d have the same configuration). It is a block diagram. As shown in the figure,
The node 2a serving as a master station and the node 2b serving as a slave station include a communication IC 4 that performs data transmission between the respective nodes 2a to 2d, and a CPU (control means) 5 that controls data transmission by the communication IC 4. It has.

Further, two reception FOTs (reception photoelectric conversion elements) 7a and 7b, two transmission FOTs (transmission photoelectric conversion elements) 8a and 8b, each reception FOT 7a and 7b, transmission FOTs 8a and 8b, and the communication IC 4 , And changeover switches (switching means) 6a and 6b for switching connection with the CPU 5. The reception FOT 7a and the transmission FOT 8a constitute a first photoelectric conversion means, and the reception FOT 7b and the transmission FOT 8b constitute a second photoelectric conversion means.

Further, prisms 9a and 9b for introducing the optical signals input to the nodes 2a to 2d into the receiving FOTs 7a and 7b and distributing the optical signals transmitted from the node 2 to the optical transmission lines 3a to 3d are provided. is doing. Then, when an abnormality occurs in any of the optical transmission lines 3a to 3d forming the ring type network, the changeover switch 6
By appropriately switching a and 6b, each node 2a-
The data communication between the CPUs 5 of the 2d is maintained.

Next, the optical transmission lines 3a to 3 of the ring type optical communication system 1 according to this embodiment configured as described above.
The operation when an abnormality occurs in d will be described. Figure 3
4 is a flowchart showing the operation of the nodes 2a to 2d when an abnormality occurs in the optical transmission lines 3a to 3d.

During normal operation (when no abnormality has occurred in the optical transmission lines 3a to 3d), the changeover switch 6a is switched so that the communication IC 4 and the reception FOT 7a are connected, as shown in FIG. And the changeover switch 6b is
The communication IC 4 and the transmission FOT 8b are switched so as to be connected.

Therefore, the transmission data output from the communication IC 4 can be distributed to the optical transmission lines 3a to 3d as optical signals, and the optical signals distributed via the optical transmission lines 3a to 3d can be converted to electrical signals. Can be received. That is, one-way optical communication is performed between the nodes 2a to 2d.

Then, in any of the optical transmission lines 3a to 3d (in this example, the optical transmission line 3c shown in FIG. 1) is used.
When an abnormality such as breakage or disconnection occurs and optical communication cannot be performed on the optical transmission line 3c (step ST in FIG. 3).
1) In each of the nodes 2a to 2d, the CPU 5 of each node detects that an abnormality has occurred in the optical transmission line (step ST2). In addition, among the optical transmission lines 3a to 3d,
A method of identifying the optical transmission line in which the abnormality has occurred will be described later.

When an abnormality occurs in the optical transmission line 3c, each of the nodes 2b to 2d serving as slave stations receives the signal output from the node 2a serving as the master station (transmits data from the master station to the slave stations). Mode changeover switch 6a, 6b is switched (step S
T3).

Further, the node 2a serving as the master station switches the changeover switches 6a and 6b so that the node 2a becomes a mode for transmitting a signal to each of the slave stations 2b to 2d.

That is, as shown in FIG. 4, in the node 2a which is the master station, the changeover switch 6a is controlled so that the CPU 5 and the transmission FOT 8a are connected, and the CPU 5
And switch FOT 8b are connected so that switch 6
Control b.

On the other hand, the node 2b (2
c, 2d), the changeover switch 6a is controlled so that the CPU 5 and the reception FOT 7a are connected, and the CPU 5
And switch FOT 8b are connected so that switch 6
Control b.

Then, the CP of the node 2a serving as the master station
U5 sends a command to confirm whether the data transmission to the nodes 2b to 2d of each slave station is secured (step ST4). The transmitted command is distributed to the optical transmission line 3d via the transmission FOT 8a of the node 2a and the prism 9a shown in FIG. 4, and is transmitted to the CPU 5 of the node 2d. Similarly, the transmission F of the node 2a
It is distributed to the optical transmission line 3a via the OT 8b and the prism 9b, and is transmitted to the CPU 5 of the node 2b. Further, the CP of the node 2c is transmitted via the node 2b and the optical transmission line 3b.
It is transmitted to U5 (step ST5).

After that, each node 2b to be a slave station
2d switches the changeover switches 6a and 6b so that the mode is a mode in which an optical signal is transmitted to the node 2a serving as the master station (a mode in which data is transmitted from the slave station to the master station) (step ST6). Further, the node 2a, which is the master station, is placed in the changeover switches 6a, 6 so that the node 2a becomes a mode for receiving the optical signals transmitted from the slave stations 2b to 2d.
Switch b.

That is, as shown in FIG. 5, in the node 2a, the changeover switch 6a is controlled so that the CPU 5 and the reception FOT 7a are connected, and the CPU 5 and the reception FOT 7a are connected.
The changeover switch 6b is controlled so as to be connected to 8b. Further, in the node 2b (2c, 2d), the changeover switch 6 is arranged so that the CPU 5 and the transmission FOT 8a are connected.
A is controlled, and the changeover switch 6b is controlled so that the CPU 5 and the FOT 7b are connected.

Each node 2b to be a slave station
2d is a node 2 which becomes a master station in a predetermined order.
The command is sent to the CPU 5 of a (step ST
7). For example, the command output from the CPU 5 of the node 2d is transmitted to the node 2a via the optical transmission line 3d, and in the node 2a, the prism 9a and the reception FOT 7 are transmitted.
It is input to the CPU 5 via a and the changeover switch 6a.

The command output from the CPU 5 of the node 2c is transmitted to the node 2a via the optical transmission line 3b, the node 2b, and the optical transmission line 3a. At the node 2a, the prism 9b, the reception FOT 7b, and It is input to the CPU 5 via the changeover switch 6b.

When the commands output from the nodes 2b to 2d of all the slave stations are input to the CPU 5 of the node 2a, it is confirmed that the communication between the node 2a and the nodes 2b to 2d has been established. , Then each node 2
By switching the changeover switches 6a and 6b of a to 2d, bidirectional data transmission between the master station and the slave station becomes possible.

Thus, even if an abnormality occurs in any one of the ring-shaped optical transmission lines 3a to 3d, the other normal optical transmission lines are used, whereby the master station It is possible to maintain the minimum data transmission between the CPU 5 of the node 2a that becomes the node and the CPU 5 of the nodes 2b to 2d that become the slave stations.

Next, the procedure for identifying the optical transmission line in which the abnormality has occurred, that is, the procedure for identifying in which of the optical transmission lines 3a to 3d the abnormality has occurred will be described. FIG. 6 is a flowchart showing the processing procedure.

First, when an abnormality occurs in any of the optical transmission lines 3a to 3d (step ST11), each node 2
A lock error is detected by the communication ICs 4a to 2d (step ST12).

Then, the CPU 5 of each of the nodes 2a to 2d
When the occurrence of the lock error is detected, the processing for changing the master station and the slave station is performed (step ST1).
3). That is, the node 2a, which is the master station, is set as a temporary slave station, and the nodes 2b to 4
2d is set as a temporary master station. This is shown in FIG.
It shows in (b).

A new master station (temporary master station)
Each of the nodes 2b to 2d thus determined sends out an optical signal for confirming the abnormality of the optical transmission lines 3a to 3d (step ST
14). At this time, as shown in FIG. 7B, the node 2a
From the node 2b to the node 2b to the node 2c, optical signals are sent in a fixed direction.

After that, each node 2 which is a temporary master station
In b to 2d, it is detected whether or not an optical signal is received (step ST15). As a result, when the reception of the optical signal is confirmed, it is determined that the optical transmission line on the upstream side of this node is normal, and the node is returned to the slave station (step ST16).

In the case of FIG. 7B, the optical signal transmitted from the node 2d is transmitted to the node 2b (temporary master station) via the optical transmission line 3d, the node 2a, and the optical transmission line 3a. In this case, since the optical signal is received by the node 2b, the node 2b is returned to the slave station. Similarly,
The optical signal transmitted from the node 2b is transmitted to the node 2c via the optical transmission line 2b, and the optical signal is received by the node 2c. Therefore, the node 2c is returned to the slave station.

On the other hand, since the optical signal transmitted from the node 2c has an abnormality in the optical transmission line 3c, the node 2
It is not transmitted to the node 2d, and the node 2d cannot receive the optical signal. In this case, the node 2d does not return to the slave station. That is, only the node 2d is a master station, and the other nodes 2a to 2c are all slave stations. After that, it is determined that an abnormality has occurred in the optical transmission path 3c on the upstream side of the node (node 2d in this case) that is finally set as the master station (step ST17).

Next, the node position address is transmitted from the node 2d, which is the master station, to the nodes 2a to 2c, which are the slave stations, and the nodes 2a to 2d have their own positions (from the optical transmission line where the abnormality has occurred). It is possible to recognize the information on what position it is located (step ST1).
9) As a result, the original master station (2a) can recognize at which position in the network the abnormality has occurred.

After that, the temporary master station and the temporary slave station are set to the original state (node 2a is the master station, node 2b ...
2d is returned to the slave station, and bidirectional data transmission between the master station and the slave station is performed by the method described above.

As described above, in the ring type optical communication system 1 according to the present embodiment, it is possible to detect an abnormality in any one of the optical transmission lines 3a to 3d forming the ring type network. Also, by using an optical transmission line other than the optical transmission line in which the abnormality has occurred, data transmission can be performed between the master station and the slave station. As a result, it is possible to deal with the abnormality of the optical transmission line without disposing a separate communication line for restoration, so that it is possible to achieve cost reduction and space saving of the device.

Further, in the ring type optical communication system 1 according to this embodiment, the entire apparatus can be downsized,
It is extremely useful when used as a network system for vehicles whose installation space is restricted.

In the above embodiment, the optical communication system having the four nodes 2a to 2d has been described as an example, but the present invention is not limited to this, and other number of nodes can be used. .

Further, in the above-described embodiment, an example of using it in a network system mounted on a vehicle has been described, but the present invention is not limited to this, and can be applied to a building or plant management system or the like. it can.

[0048]

As described above, in the ring type optical communication system according to the present invention, when an abnormality occurs in any one of the optical transmission lines forming the network, the abnormality occurs. Since it is possible to perform data transmission between the respective nodes by using another optical transmission path in which no data transmission occurs, the data transmission can be maintained. Further, unlike the conventional case, it is not necessary to provide a communication line for restoration, so that the configuration can be simplified, and the size and cost can be reduced.

[Brief description of drawings]

FIG. 1 is a configuration diagram showing a ring type optical communication system according to an embodiment of the present invention.

FIG. 2 is a block diagram showing a detailed configuration of a node serving as a master station and a node serving as a slave station.

FIG. 3 is a flowchart showing a processing procedure when an abnormality occurs in an optical transmission line.

FIG. 4 is an explanatory diagram showing a state when a signal is transmitted from a master station to each slave station when an abnormality occurs in an optical transmission line.

FIG. 5 is an explanatory diagram showing a state when a master station receives a signal transmitted from each slave station when an abnormality occurs in an optical transmission line.

FIG. 6 is a flowchart showing a procedure for identifying an optical transmission line in which an abnormality has occurred.

FIG. 7 is an explanatory diagram showing a state of switching each node to a master station or a slave station when specifying an optical transmission line in which an abnormality has occurred.

FIG. 8 is a configuration diagram of a conventional ring type optical communication system.

FIG. 9 is a configuration diagram when a recovery communication line is provided in a conventional ring type optical communication system.

[Explanation of symbols]

1 Ring type optical communication system 2a-2d nodes 3a-3d optical transmission line 4 Communication IC 5 CPU (control means) 6a, 6b Changeover switch (changeover means) 7a, 7b Reception FOT (photoelectric conversion element for reception) 8a, 8b Transmission FOT (transmission photoelectric conversion element) 9a, 9b prism

Continued front page    F term (reference) 5K002 AA01 AA03 DA04 DA11 EA06                       FA01 GA03                 5K021 AA08 BB01 CC13 DD02 FF04                       FF11                 5K031 AA08 CB11 DA02 DA15 DA19                       DB12 DB14 EA01 EB02 EC02

Claims (6)

[Claims] 1. A ring type optical communication system having a plurality of communication stations, wherein the communication stations are connected in a ring shape by using an optical transmission line to perform data transmission between the communication stations, One of the stations is a master station and the other is a slave station, and an error occurs in any one of the optical transmission lines connecting the communication stations. In, the connection between the respective communication stations at both ends of the optical transmission line in which the abnormality has occurred, using the path on the opposite side of the optical transmission line in which the abnormality has occurred,
A ring type optical communication system, wherein bidirectional data transmission is performed between the master station and the slave station. 2. A ring type optical communication system, comprising a plurality of communication stations, wherein the communication stations are connected in a ring shape by using an optical transmission line to perform data transmission between the communication stations, Among the stations, one communication station is the master station and the other communication station is the slave station, and an abnormality has occurred in the optical transmission line between the slave stations among the optical transmission lines connecting the communication stations. In this case, the path from each slave station located on both sides of the optical transmission line in which the abnormality has occurred is opposite to the optical transmission line in which the abnormality has occurred, In the case of an optical transmission line between the master station and the slave station, out of the optical transmission lines that connect the communication stations, if an error occurs in the optical transmission line Slave station located at one end of the transmission line and master station located at the other end And bidirectional data transmission between each slave station and the master station on a path opposite to the optical transmission path where the abnormality has occurred. 3. A ring type optical communication system comprising a plurality of communication stations, wherein the communication stations are connected in a ring shape using an optical transmission line to perform data transmission between the communication stations, Among the stations, one communication station is a master station and the other communication station is a slave station, and each communication station uses a control means for controlling the communication station and an optical transmission line formed in a ring shape. A communication IC for controlling transmission / reception of an optical signal, a first photoelectric conversion unit for converting an electric signal to be transmitted into an optical signal and a received optical signal into an electric signal, and a second photoelectric conversion unit, A first photoelectric conversion unit, a second photoelectric conversion unit, and a switching unit that switches connection between the communication IC or the control unit are provided, and the control unit of each communication station has an abnormality in the optical transmission line. Is not occurring, the communication IC is set to the first The switching means is controlled so as to be connected to the optical transmission path via the photoelectric conversion means and the second photoelectric conversion means, and any one of the optical transmission paths arranged between the communication stations is transmitted. If something goes wrong on the road,
A ring characterized by controlling the switching means so that the control means of the slave station and the control means of the master station are connected using an optical transmission path other than the optical transmission path in which the abnormality has occurred. Optical communication system. 4. The first photoelectric conversion means and the second photoelectric conversion means each include a reception photoelectric conversion element and a transmission photoelectric conversion element, and when an abnormality occurs in the optical transmission line. Is a mode in which data is transmitted from the master station to the slave station by switching the connection with the control means to either the reception photoelectric conversion element or the transmission photoelectric conversion element, and the slave station to the master station. 4. The ring type optical communication system according to claim 3, wherein a mode for transmitting data to the optical fiber is switched. 5. When an abnormality occurs in any one of the optical transmission lines between the communication stations, the master station is changed to a temporary slave station, and each slave station is changed to a temporary slave station. Change to a temporary master station, each temporary master station, while sending an optical signal to the optical transmission line, the temporary master station, the optical signal from the temporary master station upstream of the optical transmission path Is received, and the upstream optical transmission line of the temporary master station determined not to receive an optical signal is determined to be an abnormal optical transmission line. The ring type optical communication system according to any one of claims 1 to 4. 6. The ring type optical communication system according to claim 1, wherein the ring type optical communication system is mounted in a vehicle.