JPS59172839A - System for detecting bus failure position in bus network - Google Patents

Abstract

PURPOSE:To restore quickly a failure by obtaining the delay time of a reflected wave from a bus failed position to a transmitted wave to detect a bus failed position. CONSTITUTION:In starting communication from a terminal 5 to a terminal 11, the terminal 5 transmits a pulse for detecting bus failure to a cable 1 to check the state of the bus cable 1 and the pulse is received by a pulse failure position detector 4. If no failure exists in the cable 1, no reflected wave is generated and the detector 4 receives the transmitted wave only and does not receive the reflected wave. On the other hand, if a failure exists on the cable 1, the transmitted pulse is reflected at the failed position and detected by the detector, allowing the detector to calculate the distance from the terminal 5 to the bus failed position based on the time from the receiving of the transmitted pulse to the receiving of the reflected pulse. Thus, the bus failed position is detected to prevent malfunction and the failure is restored quickly by offering the failure position information.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for detecting the location of a bus fault in a bus network composed of flat cables, bare cables, or coaxial cables.

Conventionally, in this type of bus failure detection method, the terminal that is about to start up sends a timing signal to the terminal that is being activated to check whether it is possible to start up, and the There was a method for detecting failures in response signals, busses, and terminals.

However, this method has the drawback that although it can detect that there is a fault in the bus or terminal, it cannot detect the location of the fault, so it takes time to search for the fault.

SUMMARY OF THE INVENTION An object of the present invention is to provide a bus failure location detection system that can detect the location of a bus failure in order to be able to deal with it within a short time.

In order to achieve the above object, the bus fault location detection method according to the present invention detects the bus fault location for each terminal connected to the bus network in a fault detection method for a bus network composed of flat cables, bare cables, or coaxial cables. a device is provided, and when the corresponding terminal receives a pulse sent to the bus network for bus fault detection and further receives a reflected wave of the pulse, the device detects the reflected wave from the received pulse. The configuration is such that the position where the reflection occurs is calculated from the time until the pulse is received.

According to the configuration, the distance from the corresponding terminal to the fault location on the bus network can be detected, and the object of the present invention can be completely achieved.

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

FIG. 1 is a block diagram showing one embodiment of the present invention.

A common bus cable 1 composed of a flat cable, a pair cable, or a coaxial cable, a terminating resistor 2.3 that terminates this bus cable, a terminal 5.7.9.11 connected to the common bus cable, and this The bus failure location detection device 4.6.8.10 is added to each terminal.

Now, assuming that the terminal 5 tries to start up the terminal 11, the terminal 5 first sends a bus 1 damage detection pulse to the common bus cable 1 in order to check the status of the bus cable.

The emitted pulses are received by the bus fault location detection device 4. If there is no fault in the common bus cable 1, reflected waves will not be generated anywhere on the common bus cable, and the bus fault position detection device 4 will receive only the transmitted waves and will not receive reflected waves. In this case, common bus cable 1
This means that there are no obstacles above.

Next, if there is a fault on the common bus cable 1, there is an impedance mismatch at the fault location, so 14
The transmitted pulse is reflected at one point, and the reflected wave returns through the common bus cable and is detected by the bus fault location detection device 4.

In this case, the bus failure location detection device 4 calculates the distance from the terminal 5 to the bus failure location based on the time from reception of the transmitted pulse to reception of the reflected pulse, and then uses the timing chart shown in FIG. The operation shown in FIG. 1 will be explained.

When the terminal 5 sends out the pulse A, the pulse A is simultaneously received by the bus fault location detection device 4 as a silpal 7C.

If there is a fault on the common bus, reflection occurs at the location of the fault and a signal B occurs after 1/2 time. The reflected pulse B is detected by the bus fault position detection device 4 after 1/2 time.
, and is detected as pulse D.

Based on the delay time from pulse C to pulse D, the bus fault location detection device 4 determines the distance from the delay time to the fault location.

Due to the operation of such a bus fault location detecting device, a corresponding terminal can know the location of a bus fault, and malfunctions can be prevented.

As explained in detail above, the present invention is achieved by determining the delay time of the reflected wave from the bus failure location with respect to the transmitted wave.
By being able to detect the location of a bus fault, preventing malfunctions, and providing information on the location of the fault to maintenance personnel, it is possible to quickly recover from the fault.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an embodiment of the bus fault location detection method using the present 8AK, and FIG. 2 is a timing diagram for explaining the operation of FIG. 1. 1... Common bus cable 2.3... Common bus terminating resistor 4.6.8.10... Bus fault location detection device 5.7.
9.11...Terminal patent applicant NEC Corporation

Claims (1)

[Claims] In a fault detection method for a bus network composed of flat cables, bare cables, or coaxial cables, a bus fault location detection device is provided for each terminal connected to the bus network, and the bus fault location detection device detects when a corresponding terminal detects a bus fault. When receiving a pulse transmitted to a bus network for detection and further receiving a reflected wave of the pulse, the position where the reflection occurs is calculated from the time from receiving the transmitted pulse to receiving the reflected wave pulse. 1. A method for detecting a location of a bus fault in a bus network, characterized in that the distance from the corresponding terminal to the location of the fault on the bus network is detected by configuring the method.