JPH0710068B2 - Transmission control device - Google Patents

Description

TECHNICAL FIELD The present invention relates to a transmission control device, for example, a transmission control device of a loop communication system having a countermeasure against a failure.

2. Description of the Related Art In the conventional loop type communication system, the transmission device failure countermeasure is to duplicate the transmission, and when a failure occurs in the operation loop used for normal data transmission and the transmission path or interface section of the operation loop. It has a standby loop that is used as an alternative, and has an alternate bus function that automatically switches from the active loop to the standby loop when a failure occurs. Further, in the case of a transmission line disconnection accident or a failure in a transmission device in which the bypass function does not work, there is a loop back function in which the transmission line is folded back before the failure point.

However, in order to deal with these troubles, the transmission device always requires two sets of interfaces, an interface for controlling the active system and an interface for controlling the standby system. Therefore, the conventional transmission device has a complicated structure and is very expensive.

The present invention is intended to eliminate the above-mentioned drawbacks, and various countermeasures against obstacles are realized with a simple configuration by an input switching switch and an output switching switch and a bypass switching switch provided for an operation system loop. The present invention is to propose a transmission control device that does.

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

FIG. 1 is a diagram showing a state in which no failure has occurred, that is, a steady state. 1,2,3 are transmission devices, and 4,5,6 are operational transmission lines, which transmit information in the direction of the arrow. . 7, 8 and 9 are standby transmission lines, which do not form a loop in the steady state. 10,1
1 and 12 are interface parts of each transmission device,
Performs E / O conversion and modulation / demodulation. 13,14,15 control the information in the logic part. In addition, a switch control unit to be described later is instructed to switch. Reference numerals 16, 17 and 18 denote switch control units, which control each switching switch under the control of the logic unit (13, 14, 15) to select the switch. SW1, SW4, SW7 are switches for input signal switching, and are switches for selecting an input signal effective transmission path to be input to the transmission device (1, 2, 3). SW
2, SW5 and SW8 are switches for switching output signals, and are switches for selecting which transmission path the output information from the transmission device (1, 2, 3) is output to. SW3, SW6, and SW9 are bypass switches, and are switches that separate the transmission device (1, 2, 3) from the transmission path and select whether or not to bypass the transmission path.

Similar designations will be made from FIG. 2 to FIG. 4 below.

As shown in FIG. 1, in the steady state, SW1 to SW9 are set by the switch control units (16, 17, 18) as shown by arrows.
The standby loops 7, 8 and 9 are not connected to other loops or interface units in the transmission device in any of the switching switches, and are disconnected. On the other hand, in the operation loop, the output from the interface unit 10 of the transmission device 1 is connected to the transmission line 4 via the output signal switching switch SW2, and the output of the interface unit 11 of the transmission device 2 via the input signal switching switch SW4. It is connected to the input side, the output of the interface unit 11 is connected to the transmission line 5 via the output signal switching switch SW5, and similarly in the transmission device 3,
It is input to the interface unit 12 via SW7, the output of the interface unit 12 is connected to the transmission line 6 via SW8, and the transmission line 6 is input to the interface unit 10 via SW1 of the transmission line device 1 to form a loop. are doing.

FIG. 2 is a diagram showing a switch control state of the switch control units 16, 17, 18 when the transmission lines 4, 5 and 6 of the operation system loop cause a failure such as disconnection. SW
1 to SW9 are selected at the arrow positions.

The active transmission lines 4,5,6 are separated from the interface units 10,11,12 of each transmission device 1,2,3 and other transmission lines, and the standby transmission lines 7,8,9 are the interfaces of the transmission device 1. SW2 from Part 10
Is connected to the transmission line 9 via the transmission line 9 of the transmission device 3.
It is input to the interface unit 12 via SW7, the output of the interface unit 12 is connected to the transmission line 8 via SW8, the transmission line 8 is connected to the interface unit 11 via SW4 of the transmission device 2, and the interface unit 11 Output is SW
The transmission line 7 is connected to the transmission line 7 via the transmission line 1.
Is input to the interface unit 10 via SW1. In this way, when a failure occurs in the active loop, the transmission device can transmit information by the same control procedure regardless of whether it is the active system or the standby system simply by switching to the standby loop (alternative function).

FIG. 3 shows a countermeasure against a failure when the logic unit 13 or the interface unit 10 of the transmission apparatus 1 fails. By shorting the bypass switch SW3 and setting the output signal switching switch SW2 as a standby system, the transmission apparatus 1 is FIG. 6 is a diagram showing an example of bypassing from a loop (bypass function), which is a switch control unit when the power of the transmission device 1 is cut off, when the transmission line is not used, and the like.
When 17 is not driven, the switch is in the bypass function state.

FIG. 4 is a diagram showing a failure countermeasure implementation state applied when the active transmission path and the standby transmission path are disconnected, or when there is a failure of the transmission device in which the bypass function described above does not work,
In this example, the case where the active and standby transmission paths are disconnected at the X position is shown, and the transmission path is folded back at the transmission device in front of the failure point, and both the active and standby loops are switched. By setting the switch in the direction of the arrow in the figure, it is possible to realize exactly the same function as in the case where the loop is formed without any obstacle in the control of the transmission devices 1, 2, and 3.

In this embodiment, three transmission devices have been described, but the number of transmission devices is not limited to three, and it is needless to say that the same effect can be obtained with three or more transmission devices.

As described above, by using the transmission device according to the present embodiment in the loop communication system, the interface units are separately provided for the operation loop and the standby loop as countermeasures against a failure, but both interface units are provided. Since it can be shared only by providing a switching switch, the configuration and cost can be significantly reduced.

Further, it is possible to realize a loop-type communication system that can bypass the transmission device without adversely affecting other transmission devices connected to the loop even when the transmission device is not operating or has a failure.

Further, in a part of the loop system, even when two loops of the active system and the standby system are disconnected at the same time, only the switching of the switch does not affect the control procedure of each transmission device and the loop and the data transmission efficiency. A loop communication system capable of driving the system is realized.

As described above, according to the present embodiment, the input changeover switches SW1, 4, 7 and the output changeover switch are used when the transmission device fails or when the active transmission line and the standby transmission line are disconnected. The following functions can be realized with a simple configuration by the SW2, 5, 8 and the bypass changeover switches SW3, 6, 9 provided for the operation loop.

(B) If the transmission device fails, or if the power to the transmission device is cut off,
By bypassing the signal input from the working loop and outputting it to the working loop by the bypass changeover switch that bypasses the interface section when it is not driven (bypass function), the other transmission devices are kept in a steady state. In a similar manner, a signal from the operation loop is input to the interface section via the input changeover switch, and a signal from the interface section is output to the operation side loop via the output changeover switch. Can be maintained.

(B) If both the active and standby transmission lines are disconnected and the operation loop and the standby loop are not adjacent to the disconnection point, the signal from the active loop is bypassed and output to the active loop. At the same time, the signal from the standby loop is input to the interface section, the signal from the interface section is output to the standby loop, and if it is adjacent to the disconnection point, the signal from the operating loop or the standby loop is interfaced. By inputting the signal to the control unit and setting it to output the signal from the interface unit to a loop different from the loop to which the signal is input, by transmitting the signal in the opposite direction to the operation loop and the standby loop (loop Back function), the transmission loop can be maintained.

As described above, according to the present invention, the loopback function is realized by using the input changeover switch, the output changeover switch for the alternative bus function, and the bypass changeover switch for the bypass function. You can

[Brief description of drawings]

FIG. 1 is a block diagram of a loop communication system in a steady state, FIG. 2 is a block diagram of a loop communication system showing an alternative function when a loop transmission line is replaced, and FIG. 3 is a loop showing a bypass function when bypassing a transmission device. FIG. 4 is a block diagram of a loop communication system when a part of the loop transmission line is disconnected or when a countermeasure is taken when a bypass function fails. In the figure, 1,2,3 ... transmission device, 4,5,6 ... operating loop transmission line, 7,8,9 ... standby loop transmission line, 10,11,12 ... interface section, 13,14,15 ... Logic section, 16,17,18 ... Switch control section, SW1, SW4, SW7 ... Input signal switching switch, SW2, S
W5, SW8 ... Output signal switching switches, SW3, SW6, SW9 ... Bypass switches.

Claims (1)

[Claims] 1. An input changeover switch for inputting a signal from an active loop in a steady state and a signal from a standby loop to an interface section at the time of an alternative bus function, and the signal from the interface section in a steady state to the active system. Output switch to output to the standby loop when the alternate bus function is provided to the loop, and a signal provided from the active loop for bypass function that is provided for the active loop and bypasses the interface unit. Output switch to the operating loop, and setting means for setting the input switching switch, the output switching switch and the bypass switching switch respectively, the setting means, the setting means, the operating loop and the standby When disconnecting the system loop, the operating system loop and the standby system loop are When not adjacent to the disconnection point of the active loop, the bypass switch is set to a state in which the signal input from the active loop is bypassed and output to the active loop, and the signal from the standby loop is transferred to the interface. Setting the input changeover switch and the output changeover switch in a state in which a signal from the interface section is output to the standby loop, and when it is adjacent to the disconnection point, the operation loop or the standby loop A signal from a system loop is input to the interface unit, and the input changeover switch and the output changeover switch are set in a state in which the signal from the interface unit is output to a loop different from the loop into which the signal is input. By transmitting signals in the opposite direction to the loop and the standby loop Transmission control apparatus characterized by realizing a loopback function.