JPH04321342A - Fault detection method by token access method - Google Patents

Abstract

PURPOSE:To discriminate a fault in a short time for collection of count only without decreasing the scale of plural equipments and to simplify anti facilitate the discrimination method by discriminating it as a fault when a succeeding equipment has a count less by one based on the count of token counter of each equipment collected thereby. CONSTITUTION:Plural equipments 20.30 connecting to active and standby buses (transmission media) 11.12 have respectively token counters 21.31 to form a network and when a token frame is circulated through the active bus 11 by the token access method after the equipments are simultaneously initialized, each of the equipments 20.21 receives and sends a token and advances its own token counter 21 (31) sequentially for the count and when a fault takes place, the count of the token counters 21.31 for the busy active bus 11 is collected and a location having a count difference is discriminated to be a fault location.

Description

[Detailed description of the invention]

0001

[Industrial Application Field] The present invention relates to a token access method (Electronic Information and Communication Handbook, edited by the Institute of Electronics, Information and Communication Engineers, Ohm Inc., P2660).

0002

[Prior Art] Conventionally, a fault detection method using this type of token access method connects the transmission medium doubly for uplink and downlink, and performs connection processing to sequentially remove devices addressed to one device, while maintaining normal operation. The device was determined to be faulty when it changed from abnormal to normal.

FIG. 4A is a connection diagram showing an example of a loopback type duplex transmission medium in the token ring format.

As shown, a transmission medium 90 is connected to a device 91.
~94 was connected, and due to a failure, between devices 91 and 92,
When the active and standby rings are cut and directly connected on the device 91 side, a loop state is formed in which the paths to the devices 91, 94, 93, and 92 are connected to the paths of the devices 92, 93, 94, and 91.

In other words, this is a detection method called the loopback method, in which the fault location can be identified by cutting off the active and standby rings and sequentially changing the directly connected locations from device 91 to device 92, etc., and inspecting them.

On the other hand, FIG. 4(B) is a connection diagram showing an example of failure detection using a bypass.

As shown, a transmission medium 90, forming a duplicated token ring, skew-connects devices 91-94. In device 91, one token ring does not go into device 91, forming a bypass to connect information directly to the following device 92.

Therefore, when there is a failure in the device 91, the token ring function operates normally due to this bypass, but when there is a failure in another device, the failure state continues. In this bypass, each device is tested in turn.

[0009] In either method, each device is sequentially looped back or bypassed and, for example, the token frame transmission processing operation is investigated, thereby reducing the range of suspected failures.

0010

[Problems to be Solved by the Invention] The fault detection method using the conventional token access method described above sequentially checks the normal range for each device, and detects the fault location while reducing the range of suspected faults. Therefore, as the number of devices connected to the transmission medium increases, the time until detection increases.

[0011] Furthermore, since detection processing is performed after a fault has occurred, if the fault is an intermittent fault, the time required to detect it will further increase, making it extremely difficult to detect the location of the fault. There was a problem.

An object of the present invention is to solve the above problem by equipping each device with a token counter to count the number of cycles of tokens, and determining from the value of the token counter where the tokens do not continue to cycle due to a failure. The purpose of this invention is to provide a fault detection method using the token access method that solves the above problems.

[0013]

[Means for Solving the Problems] The basic structure of the failure detection method using the token access method according to the present invention is to connect a plurality of devices, circulate token frames, and exchange tokens for giving and receiving the right to use a transmission medium. In the fault detection method according to the access method, each device is equipped with a token counter that measures the number of times a token passes, the token counter is initialized when starting normal operation, and when the occurrence of a fault is known, the token counter is set. While disconnecting from the drive circuit, the count value of this token counter is collected from each device, and the fault location is determined from this count value.

[0014] Also, one of the devices described in the above basic configuration becomes the master device, and after initializing the token counters of each device connected via the transmission medium and issuing tokens, when it learns that a failure has occurred, it The configuration may be such that the media used and the token counter are switched to spares and disconnected, and the count values of the disconnected token counters are collected to determine the location of the failure.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, the present invention will be explained with reference to the drawings. FIG. 1 is a network diagram showing an embodiment of the token access method of the present invention.

As shown, the working bus 11 and the spare bus 12 form two rings, each connecting one master device 20 and a plurality of general devices 30.

Each device 20 is connected to the ring-shaped active bus 11.
There is a token 13 that cycles through 30 in a predetermined order. The token has the addresses of the preceding and succeeding devices for its own device.

Each device 20, 30 has a token counter 21, 31, respectively, and when it obtains the right to use the working bus 11 by means of a circulating token, the token counter 21, 3
Advance the count value of 1 by one step.

When the current bus 11 is in trouble and tokens do not flow, the current bus 11 and token counters 21 and 31
A spare bus 12 and a spare counter are connected to each device 20 and 30.

FIG. 2 is a flowchart showing an example of the operating procedure of the master device 20 of FIG.

First, when starting the operation of the system, the master device 20 connects one ring to be used to the working bus 1.
1, if there is a running token frame, it is erased (101). Next, the master device 20 instructs all the general devices 30 to initialize the token counters 31 (102), and the master device 20 sets the count value of its own token counter 21 to zero (103), and transfers the token frame to the subsequent general devices 30. (104).

[0022] This token frame returns in one cycle, so upon receiving the token frame, the master device 20 transmits the outgoing data to the working bus 11, and upon completion of the transmission, re-transmits the token frame to the subsequent general device 30. At the same time as the transmission (105), the token counter 21 of the own device 20 is incremented by one step (106).

[0023] When I learned of the occurrence of a failure (107),
The master device 20 disconnects the working bus 11 and the working token counter 21 from operation, operates the spare bus 12, and operates the spare token counter 31.
(108), and the process continues to initial setting step 101.

Following step 108, the master device 20 requests each device 30 to transmit information on the separated token counter 31, collects the information (109), and determines the location of the failure (
110) Do.

For example, when there is a failure between the master device 20 and the subsequent general device 30 or in one of the subsequent general devices 30, if the token counter 21 is counting the number N, then the subsequent general device 30 The token counter 31 of has a numerical value (N-1).

In this manner, the master device can detect a failure based on the point of change in the value of each token counter.

FIG. 3 is a flowchart showing an example of the operation procedure of the general device 30 of FIG.

When the general device 30 receives an initial setting instruction from the master device 20, it sets the token counter 31 to zero (201). Next, the general device 30 is connected to the working bus 1.
Since the token frame is received from the preceding device via 1, after transmitting the outgoing data, the token frame is transmitted to the succeeding device (202), and the value of the own token counter 31 is incremented by one step (203).

When the occurrence of a failure is notified (204), the general device 30 disconnects the working bus 11 and the working token counter 31 from operation, and switches the spare bus 12 and the spare token counter 31 (205). Connect and drive.

Next, the general device 30 becomes the master device 20
Since a request for information on the token counter 21 is received from , numerical information is returned (206) and the procedure ends.

In this embodiment, the master device instructs the initial settings and collects the count value of the token counter to determine the location of the failure. Alternatively, other control devices, adjustment devices, monitoring devices, management devices, etc. may be connected to the bus and operated.

In this embodiment, the transmission medium is shown in the form of a ring, but the above drawings and explanations are not intended to limit the present invention, since a logical ring can also be formed in a bus-type network.

[0033]

[Effects of the Invention] As explained above, the present invention updates the value of the token counter that each device has, which is the number of times the token has passed, at the time of initial setting of a network in which a plurality of devices connect to one transmission medium. By setting it to zero and determining the location of the fault based on the value of the token counter at the time the fault occurred, loop settings and bypass settings for detecting the fault location can be set for each device on the faulty network. There is no need for operations and procedures to be sequentially executed and tested, and the time required from the occurrence of a fault to the detection of a fault location can be dramatically shortened compared to the conventional method.

Furthermore, even in the case of intermittent failures, as described above, the failure location is determined based on the information at the time the failure occurred, so there is an effect that the failure location can be easily detected.

[Brief explanation of drawings]

FIG. 1 is a network diagram showing an embodiment of a fault detection method using a token access method according to the present invention.

FIG. 2 is a flowchart showing an example of the main operation procedure of the master device in FIG. 1;

FIG. 3 is a flowchart showing an example of the main operation procedure of the general device in FIG. 1;

FIG. 4 is a connection diagram showing an example of a conventional loopback method (A) and a conventional bypass method (B).

[Explanation of symbols]

11, 12 bus 20 Master device 21, 31 Token counter 30 General equipment

Claims (2)

[Claims] Claim 1: In a failure detection method using a token access method, in which a plurality of devices are connected and a token frame is circulated to give and receive the right to use a transmission medium, a token is provided to each device to measure the number of times the token passes. The token counter is equipped with a counter, and when starting normal operation, the token counter is initialized, and when the occurrence of a failure is known, this token counter is disconnected from the drive circuit, and the counted value of this token counter is collected from each device, and the counted value is A failure detection method using a token access method characterized by determining a failure location from. [Claim 2] One of the devices becomes a master device, initializes the token counter of each device connected via a transmission medium and issues a token, and then, when it becomes aware of the occurrence of a failure, the device in use and the token 2. The method for detecting failure in a token access method according to claim 1, further comprising switching the counter to a standby and disconnecting it, and collecting counts of the disconnected token counter to determine the location of the failure.