JP3082425B2 - Transmission line control method for data communication system - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a data communication system in which one master station and a plurality of remote stations are connected by a duplex loop transmission line, and more particularly to a transmission line control method when a failure occurs in a data transmission system.

[0002]

2. Description of the Related Art FIG. 2 shows an example of a data communication system of a duplex loop transmission line system. One master station 1 and three remote stations 2 ₁ to 2 ₃ is coupled by 2 system loop transmission line 3 ₂ comprising the loop transmission line 3 ₁ and a thereto opposite transmission direction of a system.

[0003] Master station 1 and remote station 2₁~ 2_ThreeBreaking inside
The line indicates the data transmission / reception path in the normal state, and the master station 1
In the normal mode, the transmission path of the 1 system and 2 system₁,
3_TwoData transmission to both of the₁Data from
Receive. Remote station 2₁~ 2 _ThreeIs in bypass mode
1 and 2 transmission line 3₁, 3_TwoReceive data from both
The same transmission path 3₁, 3_TwoTo bypass transmission.

In the above system configuration, when a failure occurs in the data transmission system such as a power-down of one of the remote stations or a disconnection of the transmission line between the stations, the transmission system is reconstructed by the loopback processing or the bypass processing performed by the failure detection station. Data transmission can be continued.

[0005] Figure 3 shows a transmission system configuration in the case of the transmission path disconnection between the remote station 2 ₁ and 2 _2. Remote station 2 ₂ switches the disconnection of one system into loopback mode upon detecting impossible the data received, transmits a zero signal to the 2 system. Similarly,
Remote station 2 ₁ is switched to the loopback mode upon detection of the disconnection of the 2 systems. The master station 1 does not detect a disconnection in both the system 1 and the system 2, and enters a bypass mode in which the system 2 reception data is used as the system 2 transmission data when any of the remote stations has a failure.

The master station constantly collects fault information of each remote station by cyclic communication, and sets a bypass mode such that the master station is set to a bypass mode when fault information is collected by loopback processing from the remote station. I do.

[0007]

In the conventional transmission path control method, the transmission system can be secured for a single failure, but there is a problem in recovery from a double failure.

[0008] Figure 4 is disconnected transmission path of the remote station 2 ₂ and 2 _3, yet showing a transmission system configuration of the double failure mode occurs remote station 2 ₃ has power down. In this configuration, master station 1 is 1
Becomes the normal mode because it detects a system disconnection (No 1 system receiving), the remote station 2 ₂ loopback mode, 2 ₁
Bypass mode, 2 ₃ becomes motionless at power-down.

[0009] When the remote station 2 ₃ has power restored double fault conditions described above, the remote station 2 ₃ transmits a signal 1 based to the master station 1 in loopback mode. The master station 1 receiving this signal receives data for both the first and second systems,
Also comprised from the remote station 2 _1, 2 ₂ to the normal mode for not notified a system disconnection. This state is the configuration shown in FIG. 5, the remote station 2 _1, 2 ₂ can receive data from the master station 1. However, the remote station 2 _1, 2 ₂ master station 1 for the master station 1 to receive data of 1 system while transmitting at 2 system data can not receive data from the remote station 2 _1, 2 _2.

[0010] After this, the master station 1 goes into bypass mode by receiving a system disconnection information from the remote station 2 ₃ becomes a transmission system configuration shown in FIG. 6, the transmission state of all stations. In other words, during the transition to 6 from 5 will be information of the remote station 2 _1, 2 ₂ are not transmitted to the master station 1. The transition period, generally takes several seconds to become the rise time of the software by the power restoration of the remote station 2 _3, there is a fault recovery is delayed problem.

It is an object of the present invention to provide a transmission line control method for quickly reconstructing a transmission system upon recovery from a double failure.

[0012]

According to the present invention, in order to solve the above-mentioned problems, one master station and a plurality of remote stations are connected by a redundant loop transmission line of a first system and a second system, and the master and each remote station are connected. Exchanges information by cyclic transmission, and the master station transmits data to the transmission lines of systems 1 and 2 and receives data from the transmission line of system 1 in the normal mode, and receives the failure information from the remote station and transmits the data in system 2. The remote station has a bypass mode in which the reception of the path is transmitted to the second system.
Bypass mode for transmitting and receiving each system and 1 when a failure occurs
In a data communication system having a loop-back mode to return the data to and from the system transmission path and 2-system transmission line, said Ma
The master station exchanges information with each other through information exchange through cyclic transmission.
Collect the disconnection information of the mote station and collect the disconnection information.
If there is a system 1 or system 2 disconnection in the
Information is exchanged by the system, and by collecting the disconnection information,
And 2 have received the information without disconnection, and
When there is no information reception from the remote station within a certain time,
Information is exchanged in the bypass mode, and the disconnection information is collected.
In the collection, both systems 1 and 2 have received information without disconnection,
And information is received from each remote station within a certain time.
And disconnection of system 1 is detected at any of the remote stations.
Information exchange by the bypass mode when
And, no disconnection 1 system and 2 based both in the collection of the disconnection information
At a certain time from each remote station
Information is received within the interval, and any of the above remote stations
Normal mode when no system 1 disconnection is detected
It is characterized by exchanging information .

[0013]

The master station confirms the remote stations existing in the transmission system by exchanging information by cyclic transmission.
When there is reception from the transmission lines of the system 2 and the system 2, the bypass mode is set. In this way, the normal mode is set when a double failure occurs, the bypass mode is entered immediately upon reception from the transmission line of system 1 due to power recovery, and the other remote station does not need to wait for the software of the remote station to be powered down. Enables reception from stations.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a transmission system control flowchart of a master station showing one embodiment of the present invention.

[0015] The master station 1, has been the exchange of information with each remote station 2 _{1-2 3} cyclically, each remote station 2 ₁
Existence confirmation and disconnection information to 2 ₃ is also collected (S1).
Then, when there is a 1-system disconnection or a 2-system disconnection of the master station (S2), the normal mode is set (S3).

[0016] 1 system in step S2, when receiving information without disconnection 2 based interpolymer, the bypass mode when there is no information received within a predetermined time from the remote station 2 ₁ to 2 ₃ (S4) (S5). Further, when there is reception within a certain time from each remote station, but any one of the remote stations detects disconnection of the system 1 (S6), the bypass mode is set (S5). When the disconnection of the first system is not detected, the normal mode is set (S3).

Under the above-described transmission system control, in the normal state of the system shown in FIG. 2, the master station performs steps S1 → S2 →
The normal mode is in the path of S4 → S6 → S3. Further, the 1-system disconnection information received from the remote station 2 ₂ The transmission line during disconnection shown in FIG. 3, step S1 → S2 → S4 →
The bypass mode is set in the path from S6 to S5.

Next, in the case of the double failure shown in FIG. 4, the normal mode is set in the route of steps S1, S2 and S3 due to the disconnection of the system of the master station itself. Then, the power supply return of the remote station 2 ₃ shown in FIG. 5, the master station 1 is immediately made to the bypass mode in the path of step S1 → S2 → S4 → S4 → S5 by disconnection return 1 system.

[0019] Thus, without the time of power restoration of the remote station 2 ₃ waits for information of 1 system disconnection due rise of software of the remote station 2 _3, immediately shifts to the state of FIG. 6 from the state shown in FIG. 4, rapid recovery become.

[0020]

As described above, according to the present invention, as a condition for shifting to the bypass mode of the master station, there is no data reception from the remote station within a predetermined time, or notification of the disconnection of the system 1 from any of the remote stations. If there is, and 1 system and 2
Since it is determined that there is a reception from the transmission line of the system, there is an effect of promptly restoring the double failure. Note that the transition to the bypass mode requires only addition of software, and does not complicate the master station.

[Brief description of the drawings]

FIG. 1 is a flowchart of a master station showing one embodiment of the present invention.

FIG. 2 is a configuration diagram of a data communication system.

FIG. 3 is a configuration diagram of a transmission system at the time of disconnection.

FIG. 4 is a configuration diagram of a transmission system at the time of a double failure.

FIG. 5 is a configuration diagram of a transmission system when power is restored.

FIG. 6 is a configuration diagram of a transmission system after receiving disconnection information.

[Explanation of symbols]

1 ... master station 2 _{1, 2} 2, 2 ₃ ... remote stations

Claims (1)

(57) [Claims] 1. One master station and a plurality of remote stations are connected to one
The master and each remote station exchange information by cyclic transmission, and the master station transmits data to the transmission lines of the first and second systems and transmits data from the first transmission line. And a bypass mode in which the reception of the failure information from the remote station transmits the reception of the secondary transmission line to the secondary system. Each of the remote stations transmits and receives the primary and secondary systems, respectively. And a data communication system having a loop-back mode for returning data between the system 1 transmission line and the system 2 transmission line when a failure occurs, wherein the master station exchanges information by cyclic transmission.
The disconnection information of each remote station is collected, and when the disconnection information is collected, if there is a 1-system disconnection or a 2-system disconnection
In the normal mode, information is exchanged, and information on disconnection of both systems 1 and 2 is obtained by collecting the disconnection information.
Information has been received and within a certain period of time
When there is no information reception in the
Exchange information and collect information on the disconnection information so that information on disconnection of both
Information has been received and within a certain period of time
Has information received at any of the remote stations.
When the 1-system disconnection is detected, the
Exchange information on the disconnection information and collect information on disconnection of both systems 1 and 2 without disconnection.
Information has been received and within a certain period of time
Receiving information, and any of the remote stations
The normal mode is used when the system disconnection is not detected.
Transmission line control method for a data communication system, characterized by exchanging information with each other.