JPS58170247A - Automatic loop back control system - Google Patents

Abstract

PURPOSE:To detect automatically a failed part of a transmission line, by performing loop back automatically in interlocking with a node device. CONSTITUTION:A monitor function 11 in an automatic loop back controlling section 10 detects the disappearance of token, and when a reproduction request function 12 detects the time-over from the function 11, the reproduction of the token is tried, a reproducing discriminating function 13 and a failure notice notice function 14 regard it as disabled communication when the trial of the token reproduction is failed for the number of specified times, and transmit a failure notice frame FI to all other node devices. When the FI from the other device is detected after the transmission of the FI, the function 15 stops the transmission of the FI and the received FI is transferred to the next node device. When a switching indication function 16 and a loop back state holding section 17 stop the transmission of the FI from itself when the FI from the other device is not received within a specified time and transmit the switching indication frame to the transmission line at the waiting side to all other node devices.

Description

[Detailed description of the invention] 4. Technical analysis of the invention The present invention relates to an automatic loopback control scheme, and in particular to an automatic loopback control scheme.

In a token-based loop network system that performs mutual communication between multiple devices connected to a loop-configured transmission path, it is not possible to have the monitoring device also have a failure countermeasure function, but to ensure that all devices have equal functions. Automatic loop check control method (BL) that automatically checks loops for transmission path failures after checking A token method is known as one of the methods.

I token I means the transmission right to temporarily use the transmission path, and only one cough token is allowed to exist in a network system, and it is circulated among devices in the system in order. ), when the device that issued the transmission request receives the token.

The token is captured, and when the data transmission is completed, the token is returned to the first transmission line.

As mentioned above, in the token method, 1 in a half network
All devices in the system capture and use the token.

The ability to monopolize a transmission path for transmission (possible, but the maximum amount of time a device can capture a token is limited, and at least all devices can capture a token within a certain amount of time) It is designed to give you the opportunity to capture and use.

In the system described above, it is conceivable that a token may be lost due to some kind of failure. The disappearance of a token is detected by staying at the device 3 in a state of waiting for a token and monitoring whether or not tokens come around at the above-mentioned regular intervals. When the loss of a token is detected, an attempt is made to regenerate the token. There may be a unique method for regenerating the token, but in the case of a system that does not have a specific monitoring device, it is difficult to determine which device will regenerate the token among the multiple devices that detected the token's disappearance. In the case of a temporary failure, all you have to do is decide what to do.

It may be possible to successfully regenerate the token and return to normal operation, but in the case of a permanent failure such as a disconnection of the transmission line, token regeneration will fail even after a specified number of attempts.

In such cases, traditional systems with monitoring devices
The monitoring device finds the fault location and automatically removes the ivy in a system with a loop configuration.

Alternatively, it was performed manually by an operator.

However, the conventional system that uses a monitoring device has the disadvantage that if the monitoring device fails, it cannot be recovered from the failure (and the entire system goes down).For this reason, high reliability is required. The systems used here take measures such as duplicating monitoring equipment, making them expensive systems.

(C) Object and structure of the invention One object of the present invention is to provide
It is an object of the present invention to provide a method that can automatically find faults in transmission lines.

Another object of the present invention is to avoid problems found even without a monitoring device.

An object of the present invention is to provide a method that can automatically perform loopback. Therefore, in the automatic loopback control system of the present invention, w number of devices are connected to the transmission path of the loop configuration. In a network system configured with a duplex loop using the token method, the time monitoring function detects the disappearance of a token, and in response to the disappearance of the token, it starts broadcasting a failure notification to all other devices. Function to do.

A time monitoring function that monitors whether a failure notification issued from another device is received within a specified time after starting the failure notification, and if a failure notification is received from another device within the specified time, A function that stops sending failure notifications and forwards the received failure notifications as they are to the next device.If a failure notification is not received from another device within the above specified time, the function stops sending failure notifications and receives the failure notifications from the own device. A function that loops back on the side and sends a switching instruction to all other devices to switch to the transmission line on the standby side.If the switching instruction is received and the switch is not in the loopback state, The father switching path function, the function to start broadcasting failure notifications again after switching to the standby side transmission path, and the ability to receive the next failure notification within a specified time after receiving a failure notification from another device. The node device has the following functions: a time monitoring function that monitors the token every time, and a function that returns to the time monitoring state that assumes that a loopback path has been established and detects token loss again if a failure notification is not received within the specified time. It is characterized in that the node devices cooperate to automatically perform loopback. This will be explained below with reference to the drawings.

+D) Embodiments of the Invention In Figures 1 to 5, M and M' are transmission lines having a loop configuration, and A, B, C, and D are transmission lines.

A node device that shares the transmission path M as a communication medium is shown. Now, if device A wants to send data to device C,
Device A circulates on transmission path M and collects 116 token frames. After that, device A transmits a data frame for destination C. When the data frame reaches device C, device Device C recognizes that the data frame is addressed to it and receives it. When device A runs out of data to send, it returns the token 7-ray jA to transmission path M. In this way, it sends The device you want to
By capturing a frame, it can be transmitted. In the case of the token method, it operates as described above, but the following 1
The Rubno method of the present invention will be explained below.

Now, as shown in FIG. 2, consider a case where point f of the transmission path between device A and device A is disconnected. In this case, the token frame disappears at one point in time, and no further device can transmit it. In order to detect such disappearance of the token, each device retains the token (X 0 o'clock).

Time is considered, and if a token does not arrive within a specified time, it is considered to be lost. When the loss of a token is detected, an attempt is made to regenerate the token as described above. When the transmission line is disconnected.

Even after regenerating the token the specified number of times, it fails.

In this way, all devices A, B, C, and D detect the communication failure, and each device receives a failure notification frame FI.
(At, F IfBl, F I(C1, F IfD
) starts sending. The failure notification frame is a broadcast communication frame that is addressed to all devices. The device detected the failure.

Until a failure notification frame is received from another device.

Continue to send failure notification frames from the own device.

When receiving a failure notification frame from another device, it stops its own transmission, and thereafter forwards the failure notification frame from the other device to the next device as is. As a result, devices B, C, and D receive fault notification frames F I +BL F I tcl, FlIDl from their own devices, as shown in the ``) v3 diagram.
transmission is stopped, and the fault notification frame from device A (
5) will be transferred. This allows all devices to know that the transmission path is disconnected on the receiving side of device A. After the failure notification frame starts to be transmitted, it is monitored whether the failure notification frame is received from another device within a specified time. Device A is.

A timeout occurs and the device recognizes that it is one of the devices closest to the cutting point f. Device A stops transmitting the failure notification frame, loops back on its own receiving side as shown in Figure 4B, and switches all devices to the standby side loop configuration transmission path M'. The device that receives the switching instruction frame transmits the switching instruction frame, and after transmitting it to the next device, transfers it to the standby side transmission path M.
' and perform two steps. Devices B, C, and D, which have switched to the transmission path M' on the standby side, start transmitting failure notification frames F IIBI and F I (C1, F I (D)) again. As a result, this time, As shown in Figure 4, the failure notification frame FI (9) from the device remains until the end and is notified to all devices, and the receiving side of the device knows that the transmission path is disconnected. be able to.

As a result of monitoring for one hour, the equipment learns that it is one of the equipment closest to the cutting point f.

As device A did, it loops back the received image of its own device as shown in LB in Figure 5, and also switches all devices to transmission line M on standby N (previously active side). Send an instruction frame. Device B receives the switching instruction frame.

C switches the loop again, but since device A is in a loopback state, the switching instruction is ignored.

In the manner described above, a loopback path is established as shown in FIG. If the failure notification frame is sent again from all the devices in this state, all the devices will receive the failure notification frame from the other devices.

All devices stop sending failure notification frames from their own devices. If the 0th order failure notification frame is not received within a specified time after receiving the failure notification frame, a loopback path will be established. As a result, all devices go into a time monitoring state to detect the disappearance of the token again. Later,
An attempt is made to regenerate the token as described above, resulting in a one-shield action.

FIG. 6 shows each node device A shown in FIGS. 1 to 5,
The reference numeral 1O in the figure 0, which shows the configuration of an embodiment corresponding to B, C, and D, is an automatic loop back control unit which will be detailed in the OFF figure, 20 is a loop control unit, and 21 is received data. An analysis circuit, 22 a transmission data generation circuit, 23 a selection circuit, 24 a delay circuit, 25 a selection circuit, and 26 a reception buffer.

27 is a transmission buffer, 28 is a working transmitter/receiver, 29 is a standby transmitter/receiver, 30 is a node controller, 40 is a transmitter/receiver unit, 50 is a connection device, 231 and 232 are respective switching instructions, and M and M' are true. "; Represents a transmission path corresponding to the Iv1 diagram, etc.

The basic operation of the node device can be considered as follows. That is, when the active transmitter/receiver 28 receives a frame, the received data analysis circuit 21 analyzes the contents of the frame. The frame is then sent to the delay circuit 24. If the frame is unrelated to the own device, the frame is determined by the selection circuit 25 from the delay circuit 24, and is sent out from the working transmitting/receiving section 28 onto the working transmission line M. Frames addressed to the own device are taken into the reception buffer 26 and notified to the connected device 50. Transmission data from the connection device 50 is set in the transmission buffer 27. Correspondingly, the transmission data generation circuit 22 places the transmission data in a predetermined format on the frame and the 0 selection circuit 23
From there, the signal passes through the selection circuit 25 and is sent onto the transmission line M by the active transmitter/receiver 28 .

The off diagram is the automatic loop back control section lO shown in FIG.
Reference numeral 1 in FIG. 1 shows a token monitoring function, 12 a token regeneration/replacement instruction function, and 17 a loop back status display unit.

Reference numeral 18 represents an AND circuit, and reference numeral 19 represents an FFI viewing function for fault notification intervals.

The automatic loop variation control section lO shown in the off-figure is.

This is aPk newly added in the present invention.

It detects the occurrence of the conditions described with reference to FIGS. 1-5 and issues instructions to perform the necessary actions. The outline is as follows. That is, (1) the token monitoring function 11 performs time monitoring to detect the disappearance of a token.

(2) When the token regeneration request function 12 detects a time over (lost token) from the token monitoring function 11, it attempts to regenerate the token.

(3-tone regeneration judgment function 13 and fault notification device 1@14
That is, when attempts to regenerate the token fail a specified number of times, it is assumed that 0 communication is impossible, and a -failure notification frame F I (*) is sent to all other node devices.

(4) The failure notification monitoring function 15 monitors whether or not a failure notification frame issued from another device is received within a specified time after sending out the failure notification frame. Then, when one fault notification from another device is detected, the fault notification frame FI from the fault notification device 1@14 described above is sent.
The transmission of (*) is stopped, and thereafter the received failure notification frame (from another device) is transferred to the next node device.

(5) The switching instruction function 16 and the loop-back state floor holding unit 17 transmit a failure notification frame from itself when it does not receive a failure notification frame from another device within the specified time in the above process (4). , and switches to the standby transmission path M' for all other node devices, and sends out a switching instruction frame.

(6) When the AND circuit 18 receives the switching instruction frame, if it is not in the loop back state, it causes the transmission line M to switch. and,
At this time, the above-mentioned failure notification function 14 is activated, and the failure notification frame is again sent out to all node devices.

(7) The fault notification interval isoso monitoring function 19 performs the above processing (
From the state in which a failure notification frame is detected from another device in step 4), the device monitors whether the next failure notification frame is received within a specified time.

If a failure notification frame is not received within a specified time, it is assumed that a loop back path has been established, and the token monitor 1111 is activated.

FIG. 8 shows the connection state li- in the selection circuit 25 at the time of switching to the active side, that is, at the normal time.

FIG. 9 shows the connection states of the selection circuits 25 for the devices B, C, and D shown in FIG. 4 at the time of switching to the standby side. Figure 0 represents the connection state of the selection circuit 25 for the device A shown in Figure 5 at the time of loop back switching. FIG. 211 shows the connection state 1 of the selection circuit 25 for the device shown in FIG. 5 at the time of loop back switching.

tlli,) As described in detail, according to the present invention, even if no special monitoring equipment is installed, the disconnection point of the transmission path can be detected by cooperation of all the node devices in the loop network system. It is possible to automatically detect, notify all node devices, and automatically perform a loop back to return to normal operation.

[Brief explanation of the drawing]

1 to 5 are explanatory diagrams illustrating aspects of processing according to the present invention, and FIG. 6 is an exemplary configuration corresponding to each node device A, B, C, and D shown in FIGS. 1 to 5. , the OFF diagram shows the configuration of an embodiment of the automatic loop-back control section shown in FIG. 6, and FIGS. 8 to 11 are explanations explaining connection states by selection circuits corresponding to various connection states according to the present invention, respectively. Show the diagram. In the figure, 1M is a loop configuration transmission line on the active side, 1M' is a standby loop configuration transmission line, A, B, C, and D are node devices, respectively, and 10 is an automatic loop back control unit. 20 represents a loop control section, 30 a node control section, and 40 a transmitter/receiver unit.

Claims (1)

[Claims] A plurality of devices are connected on a transmission line in a loop configuration,
In a network system configured with a duplex loop using the token method, there is a time monitoring function that detects all token disappearances, a function that starts broadcasting failure notifications to all other devices in response to the token disappearance, and A time monitoring function that monitors whether a failure notification issued from another device is received within a specified time after starting a cough notification, and if a failure notification is received from aIIt within the specified time above, A function that prevents the sending of failure notifications and forwards the received failure notifications as is to the next device. If a fault notification is not received from another device within the above specified time, the fault notification is stopped and looped back on the receiving side of the own device, and the transmission line on the standby side is sent to other i&Qin devices. A function to broadcast the instruction to switch to w/J9, an alternate path function to switch to the standby transmission line if the loop batter state is not reached when the instruction to switch to the current switch is received,
A function to start broadcasting fault notifications again after switching to the standby transmission path, and a time to monitor whether the next fault notification is received within a specified time after receiving a fault notification from device a. The node device is configured to have each function of a monitoring function, and a function of returning to a time monitoring state of detecting disappearance of the token again by assuming that a loopback path has been established if a failure notification is not received within the specified time, An automatic loopback control method characterized in that node devices cooperate to automatically perform loopback.