JPH02205136A - Pseudo fault generating system - Google Patents

Abstract

PURPOSE:To realize a pseudo fault only by operating communication equipment being positioned at a nearest part geographically by setting the same address of the communication equipment at an upstream position by one than its own communication equipment on a transmission line as that of its own communication equipment. CONSTITUTION:The pseudo fault can be generated on a system by setting the same address as that of the communication equipment 1 on the communication equipment N being positioned at the upstream by one. At this time, when a transmission frame addressed to either another communication equipment is sent from the communication equipment 1, the communication equipment N deletes the frame without performing re-transmission judging it as a transmission frame transmitted from the transmission origin address of the transmission frame by its own even when the communication equipment whose address is designated receives the frames and performs the re-transmission to the transmission line after attaching reception confirming information, therefore, the communication equipment 1 judges that no transmission frame is returned due to the fault on the transmission line, and outputs the information of the fault to a processor 21.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a pseudo-failure generation method, particularly in a communication system that performs communication using a loop-shaped transmission path, in which a transmission frame transmitted from one communication device on the transmission path is used. The present invention relates to a pseudo-failure generating method for testing whether or not a communication device normally performs processing when a communication device goes around the communication system and is not correctly received by the communication device.

[Conventional technology]

Conventionally, this type of pseudo-failure generation method turns off the power of all communication devices on the transmission path other than the communication device under test, and connects these communication devices with a bypass circuit that is automatically closed when the power is turned off. By disconnecting the communication system from the communication system, a loop-shaped transmission path is created in an unestablished state, and a transmission frame without reception confirmation information is received.

[Problem to be solved by the invention]

The pseudo failure generation method described above turns off the power to all but one communication device on the transmission path, so it is suitable for large-scale communication systems where multiple communication devices are often installed in remote locations. However, this method has the disadvantage that it takes a lot of effort and time to generate a pseudo failure.

[Means to solve the problem]

The pseudo failure generation method of the present invention is applied to a one-way loop type communication system in which when a transmitted frame is correctly received, reception confirmation information is added to the transmitted frame and returned to the own communication device. It is constructed by setting the address of the communication device one upstream to the same as the address of its own communication device, and transmitting a normal transmission frame to obtain a pseudo failure state of the communication system.

〔Example〕

Next, the present invention will be explained with reference to the drawings.

FIG. 1 is a block diagram of a system to which an embodiment of the present invention is applied. In FIG. A loop-shaped communication network for performing transmission is formed, and processing units 21, 22-2N, such as communication terminals and computers, are connected to each of the communication devices 1, 2-N. Further, each of the communication devices 1.2 to 1.N is given an address for identifying a communication node, and each communication device has its own address holding circuit constituted by a switch or the like.

In normal communication, when a communication device that has obtained transmission rights using a token method or the like sends a transmission frame that includes the addresses of its own and the other communication device, the communication device to which the address was specified receives the contents of this frame and , adds reception confirmation information to this frame and sends it out to the transmission path again. Based on the reception confirmation information added to the returned transmission frame, the transmitting communication device discards the frame, assuming that the reception was successful.

Next, to explain the occurrence of a pseudo fault according to the present invention in the above-mentioned system, for example, in order for the communication device 1 to generate a pseudo fault on the system, the communication device N one upstream from the communication device 1 must be Set the same address as 1. This address setting is generally performed by manually operating the self-address holding circuit in the Tsushin fN. Therefore, when communication device 1 sends a transmission frame addressed to any other communication device, the communication device with the specified address receives this frame, adds reception confirmation information, and resends it to the transmission path. , communication device N discards the transmission frame from the source address of the transmission frame without retransmitting it as the transmission frame itself transmitted.
assumes that the transmitted frame is not returned due to a system failure, and outputs a failure notification to the processing device 21.

〔Effect of the invention〕

As explained above, in a communication system configured with a loop-shaped transmission path, the present invention enables the address of a communication node of a communication device to cause a pseudo-failure in which a loop is not established to be generated.
By setting this also in a communication device one upstream of the communication device, a pseudo failure can be generated, so that there is an effect that can be achieved only by operating the geographically closest communication device.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of a system to which an embodiment of the present invention is applied. 1.2-N...communication device, 21.22-2N...processing device.

Claims (1)

[Claims] In a one-way loop type communication system in which when a transmitted frame is correctly received, reception confirmation information is added to the transmitted frame and the frame is returned to the own communication device, the address of the communication device one upstream from the own communication device on the transmission path. A pseudo-failure generation method characterized in that a pseudo-failure state of a communication system is obtained by setting the address to be the same as the address of its own communication device and transmitting a normal transmission frame.