JPH08320844A - Sequential propagation type transmission system - Google Patents

Abstract

PURPOSE: To specify a fault place and facilitate maintenance operation by comparing sent data with returned data and informing a main transmission control part of fault occurrence when the comparison result indicates a discrepancy. CONSTITUTION: The main transmission control part 4 instructs the execution of fault detection processing with a maintenance operation instruction signal and a fault place demarcating circuit 8 once receiving data from one device connected adjacently by a transmission line sends the data back to the device as it is. Further, the fault place demarcating circuit 8 sends data that a route switching circuit 7 currently holds to the other device which is connected adjacently by a transmission line and compares data sent back by the device with the sent data. Thus, the sent data are compared with the sent-back data to decide that a fault occurs on the transmission line to the latter device unless both the data match each other.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sequential propagation type transmission system in which data is sequentially transmitted between a plurality of devices connected by a transmission line.

[0002]

2. Description of the Related Art In a sequential propagation type transmission system for sequentially transmitting data between a plurality of devices having arbitrary functions, each device is continuously connected by a bidirectional transmission path capable of bidirectional data transmission. There is. Each device is equipped with a route switching circuit that switches the transmission / reception of data connected to the bidirectional transmission line and the transmission direction, and data transmission with other devices is possible via the route switching circuit. It has become.

In the conventional sequential propagation type transmission system, each device only switches transmission / reception to / from the bidirectional transmission line by the route switching circuit.

[0004]

However, in the conventional sequential propagation type transmission system as described above, when a plurality of devices are continuously connected, a failure occurs in any of the bidirectional transmission paths. However, it was difficult to identify where the failure occurred.

The present invention has been made in order to solve the problems of the above-mentioned conventional techniques, and it is an object of the present invention to provide a sequential propagation type transmission system which identifies a faulty part and facilitates maintenance work. To aim.

[0006]

In order to achieve the above object, a sequential propagation type transmission system of the present invention comprises a plurality of devices connected by a transmission path capable of bidirectionally transmitting data, and the plurality of devices are respectively connected to the above-mentioned devices. In a sequential-propagation type transmission system including a route switching circuit for switching transmission / reception of data to / from a transmission line and switching a transmission direction, a control line for transmitting a control signal for detecting a failure occurrence, and the control line Connected to the multiple devices by
A main transmission control unit that periodically outputs a maintenance operation instruction signal for instructing each of the plurality of devices to execute a failure detection process, and instructing the plurality of devices to execute a failure detection process by the maintenance operation instruction signal. Then, when data is received from one of the devices connected next to each other by the transmission path, the data is returned to the one device as it is, and the data currently possessed by the route switching circuit is transferred to the transmission device. When the data is sent back to the other device connected next to it by a route and the data is sent back from the other device, the sent data is compared with the returned data, and when the comparison result does not match, the main data is sent. It is characterized in that each of the transmission control units is provided with a failure point isolation circuit for notifying the occurrence of a failure.

At this time, the fault location isolating circuit holds the data currently possessed by the route switching circuit.
Data tank circuit, a second data tank circuit that holds data from one device that is adjacently connected by a transmission line, and a third data tank circuit that holds data from the other device that is adjacently connected by a transmission line Data tank circuit, a comparison circuit for comparing the data held in the first data tank circuit and the third data tank circuit, the first data tank circuit, the second data tank circuit, the A control means for controlling the operation of the third data tank circuit and the comparison circuit and transmitting the comparison result of the comparison circuit to the main transmission control unit may be provided.

[0008]

In the sequential propagation type transmission system of the present invention configured as described above, the main transmission control unit gives an instruction to execute the fault detection processing by the maintenance operation instruction signal, and the fault location isolating circuit is arranged next to the transmission line. When the data from one of the connected devices is received, the data is returned to the one device as it is.

Further, the fault location isolating circuit transmits the data currently possessed by the route switching circuit to the other device connected next to it by the transmission line, and when the data is returned from the other device, it transmits. Compare the data with the returned data.

At this time, since the fault location isolation circuit provided in each device performs the same operation, the previously transmitted data is directly returned from the other device. Therefore, by comparing the transmitted data and the returned data, it is possible to determine that a failure has occurred between the transmission paths with the other device when the two data do not match.

[0011]

Next, an embodiment of the present invention will be described with reference to the drawings.

FIG. 1 is a diagram showing the configuration of a sequential propagation type transmission system of the present invention. FIG. 1A is a block diagram of the entire system, and FIG. 1B is a block diagram of a fault location isolation circuit. Further, FIG. 2 is a timing chart showing an operation state of the fault location isolation circuit shown in FIG.

As shown in FIG. 1A, in this embodiment, a first device 1, a second device 2, and a third device 3 having arbitrary functions as devices constituting a sequential propagation type transmission system. Is illustrated. Each device is connected by a bidirectional transmission path 5 capable of bidirectional data transmission, and a control line 6 for transmitting a control signal for collectively managing the data transmission state is connected thereto.

Further, in each device, a route switching circuit 7 for switching transmission / reception of data to the bidirectional transmission line 5 and switching of the transmission direction, and a fault location separating circuit 8 for identifying a fault location. Are provided, and the main transmission control unit 4 that outputs a control signal for controlling each fault location isolation circuit 8 is connected to the control line 6.

In FIG. 1B, each fault location isolating circuit 8 is adjacent to a first data tank circuit 11 which holds the data currently possessed by the route switching circuit 7 and a bidirectional transmission line 5. A second data tank circuit 12 for holding data from one device connected to the third data tank circuit 13 and a third data tank circuit 13 for storing data from the other device connected next to the two-way transmission line 5 A first data tank circuit 11, a second data tank circuit 12, a comparison circuit 15 for comparing the data held in the first data tank circuit 11 and the third data tank circuit 13,
It comprises a third data tank circuit 13 and a control means 14 for controlling the operation of the comparison circuit 15.

In such a structure, next, as shown in FIG.
As shown in FIG. 2, the operation of the fault location isolation processing of the sequential propagation type transmission system will be described with reference to FIG. 2 by taking as an example the case where a fault occurs between the second device 3 and the third device 3. . In the following description, the operation of the fault location isolation circuit 8 of the second device 2 is described as an example, but each device performs the same operation as that of the second device 2 with respect to both adjacent devices.
Further, the maintenance operation for specifying the failure point is executed by the failure point isolation circuit 8 of each device in accordance with the instruction of the maintenance operation instruction signal S which is periodically sent from the main transmission control unit 4 to each device via the control line 6. It

As shown in FIG. 2, when the main transmission control unit 4 sets the maintenance operation instruction signal S to the active state of "1" and transmits it to each device, the fault location isolation circuit 8 is not shown via the control line 6. Each time the system clock CLK transmitted from the clock generating means of (1) rises, the fault location is isolated in the following procedure.

First, at the first rise of the system clock CLK (a in FIG. 2), the control means 14 of the fault location isolating circuit 8 transfers the data currently possessed by the route switching circuit 7 to the first data tank circuit 11 Accumulate in.

Next, at the second rising edge of the system clock CLK (b in FIG. 2), the data held in the first data tank circuit 11 is transmitted to the third device 3, and at the same time, the first device. The data sent from No. 1 is stored in the second data tank circuit 12.

Next, at the third rise of the system clock CLK (c in FIG. 2), the data held in the second data tank circuit 12 is returned to the first device 1 as it is,
At the same time, the data sent from the third device 3 is stored in the third data tank circuit 13. At this time, the third device 3
The data sent from is the data that was previously sent to the third device 3 and returned as is.

Finally, at the fourth rising edge of the system clock CLK (d in FIG. 2), the first data tank circuit 11
And the data held in the third data tank circuit 13 are transferred to the comparison circuit 15, and the comparison circuit 15 compares the two data and returns the comparison result to the control means 14.

Here, when a failure occurs between the second device 3 and the third device 3 as shown in FIG.
The comparison circuit 15 of the second device 2 detects a mismatch between the two data as a comparison result. At this time, the control means 14 of the second device 2 determines that a failure has occurred between the second device 2 and the third device 3, and the result is determined as the control line 6
To the main transmission control unit 4 via.

The main transmission control unit 4, which has received the fault notification from the second device 2, notifies the system control unit (not shown) of the fault and the location of the fault, and the system control unit gives an instruction (not shown). The occurrence of a failure and the location of the failure are displayed on a display device or the like.

On the other hand, when the main transmission controller 4 sets the maintenance operation instruction signal S to the non-active state of "0", each device uses the first data tank circuit 11 to transmit and receive normal data. To do.

Therefore, it becomes possible to specify the failure point of the sequential transmission type transmission system with a simple circuit configuration.
Maintenance work becomes easy. Further, since the faulty part can be identified with a few clocks, the processing can be completed in a short time.

In this embodiment, three devices are explained as an example of the sequential propagation type transmission system, but the number of devices is not limited to three, and four or more devices are connected. However, this embodiment can be applied.

Further, in the example in which the occurrence of a failure is detected by comparing the data transmitted from the second device 2 to the third device 3 with the data returned from the third device 3 to the second device 2. As described above, the data transmission direction is from the second device 2 to the third device.
The data transmitted from the second device 2 to the first device 1 and the data returned from the first device 1 to the second device 2 are compared with each other to detect the failure. Occurrence may be detected. In this case, the second device 3 and the third device 3
The failure that occurs during the period will be detected by the third device 3.

[0028]

Since the present invention is constructed as described above, it has the following effects.

A main transmission control unit for periodically outputting a maintenance operation instruction signal for instructing the execution of the failure detection processing to each device is provided. When receiving data from one of the connected devices, the data is sent back to the other device as it is, and the data currently possessed by the route switching circuit is transferred to the other device connected next to it by the transmission path. When data is sent and data is returned from the other device, the transmitted data is compared with the data returned from the other device, and if the comparison results do not match, the main transmission control unit is notified of the failure occurrence. By providing each device with a separation circuit, it becomes possible to identify a failure point in the sequential propagation type transmission system with a simple circuit configuration, and maintenance work becomes easy.

[Brief description of drawings]

FIG. 1 is a diagram showing a configuration of a sequential propagation type transmission system of the present invention, FIG. 1A is a block diagram of the entire system, and FIG. 1B is a block diagram of a fault location isolation circuit.

FIG. 2 is a timing chart showing an operation state of the fault location isolation circuit shown in FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 1st apparatus 2 2nd apparatus 3 3rd apparatus 4 Main transmission control part 5 Bidirectional transmission path 6 Control line 7 Direction switching circuit 8 Fault location isolation circuit 11 1st data tank circuit 12 2nd data Tank circuit 13 Third data tank circuit 14 Control means 15 Comparison circuit CLK System clock S Maintenance operation instruction signal

Claims (2)

[Claims] 1. A route switching circuit in which a plurality of devices are connected by a transmission path capable of bidirectionally transmitting data, and the plurality of devices respectively perform switching of transmission / reception of data to / from the transmission line and switching of a transmission direction. In a sequential propagation transmission system equipped with, a control line for transmitting a control signal for detecting the occurrence of a fault, and the control line is connected to the plurality of devices, and a fault detection process is executed for each of the plurality of devices. Has a main transmission control unit that periodically outputs a maintenance operation instruction signal, and the plurality of devices are connected next to each other by the transmission path by a failure detection processing execution instruction by the maintenance operation instruction signal. When the data from one device is received, the data is returned to the one device as it is, and the data currently possessed by the route switching circuit is sent. Data to the other device connected next to it by the transmission path, and when data is returned from the other device, the transmitted data is compared with the returned data, and the comparison result is inconsistent. A sequential propagation type transmission system, characterized in that each of the sequential transmission type transmission circuits is provided with a fault location isolating circuit for notifying the main transmission control unit of a fault occurrence. 2. The sequential propagation type transmission system according to claim 1, wherein the fault location isolating circuit is adjacent to the first data tank circuit for retaining the data currently possessed by the route switching circuit, and the transmission line. A second data tank circuit for holding data from one device connected to the second data tank circuit; a third data tank circuit for holding data from the other device connected next to the other device by a transmission path; A comparison circuit for comparing the data held in the data tank circuit and the third data tank circuit, the first data tank circuit, the second data tank circuit, the third data tank circuit, and the comparison circuit And a control means for transmitting the comparison result of the comparison circuit to the main transmission control section.