JPS61267428A - Information communication system - Google Patents

Abstract

PURPOSE:To improve remarkably the reliability of the titled system by providing hardware detecting a fault of a transmission line to disconnect once the fault from the line, applying self-diagnosis of output error and continuing the disconnected state when the output is in error in each transmission and reception station. CONSTITUTION:Supposing that a fault an output signal 101 of a transmission and reception circuit 4 is always at '0' takes place, then a relay 15 is operated at normal operation and since a contact 16 is closed, the level of a transmission signal 100 goes to 0. In this case, a reception signal 102 of the circuit 4 and a carrier sense signal 103 go to 0 and the relay 15 is released through a relay driver 14. When the relay 15 is released, the contact 16 is opened to disconnect the transmission line 1. In a node where a fault that the output signal 101 of the circuit 4 is always '0' takes place, since the output signal 101 remains 0, the disconnecting state of the transmission line 1 continues.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to an information communication system, and particularly to a contention-based packet communication system in which transmission path resources are shared among a plurality of information processing devices.

[Background of the invention]

In a conventional contention-based packet communication system, it is generally known in Japanese Patent Application Laid-Open No. 77258/1983 that the negative effects on the transmission path can be eliminated when power is turned on, shut off, or reset at each transmitter/receiver station arbitrarily. However, there is no mention of system failures due to failures such as short circuits at the transmitter/receiver station.

[Purpose of the invention]

An object of the present invention is to provide a contention type information communication system in which transmission path resources are shared between a plurality of transmitting and receiving stations.
An object of the present invention is to provide a highly reliable information communication system that secures the health of the system by detecting an abnormality in the output of a transmitting/receiving station and disconnecting the transmitting/receiving station from the transmission path.

[Summary of the invention]

The present invention detects an abnormality in a transmission path in each transmitting/receiving station (hereinafter referred to as a node) of a contention type information communication system, disconnects the transmission path from the transmission path, and performs a self-diagnosis for an output abnormality. It is characterized by maintaining the integrity of the transmission path by providing hardware that maintains the disconnected state.

[Embodiments of the invention]

Embodiments of the present invention will be described below with reference to FIGS. 1 to 4.

FIG. 4 shows a contention type information communication system to which the present invention is applied. Reference numeral 1 indicates a common transmission path, and reference numeral 2 indicates a node which is a transmitting/receiving station. FIG. 1 shows a block diagram of a node 2 which is an embodiment of the present invention.

The node 2 includes a control circuit 3 that controls communication, a transmitter/receiver circuit 4 that performs transmission and reception with respect to the common transmission line 1, a line disconnection circuit 5 that disconnects the common transmission line 1 from the transmitter/receiver circuit 4, and a power supply that monitors the power supply voltage. In response to signals from the voltage monitoring circuit 6, the power supply voltage monitoring circuit 6, and the reset switch 8, the control circuit 3
, a transmitting/receiving circuit 4 , a line disconnection circuit 5 , a reset circuit 7 that outputs a reset signal, and an output abnormality detection circuit 9 that detects an output abnormality of the node 2 and outputs a disconnection signal 104 to the line disconnection circuit 5 . 0 The features of this embodiment are as follows.
By adding an output abnormality detection circuit 9 to the next node, if the common transmission line 1 becomes abnormal, a function is added to self-diagnose the output of node 2 and disconnect the line by itself in the event of an output abnormality. be.

Next, the operation of this embodiment will be explained.

FIG. 2 shows detailed circuits of the transmitting/receiving circuit 4, a part of the line disconnection circuit 5, and the output abnormality detection circuit 9 of this embodiment. FIG. 3 shows an operation time chart of the first embodiment.

At time T1, the output signal 101 of the transmitter/receiver circuit 4 is always "O".
”, the relay 15 is operating during normal operation and the well point 16 is on, so the transmission line signal 100 also becomes “0”. At this time, the transmission line signal 100 becomes “0”. The received signal 102° and the carrier sense signal 103 of the control circuit 3 which detects the pulse signal of the transmission line 1 are also r.
Becomes O.J. As a result, the output signal 1 of the OR gate 12
04 becomes "0", and the output signal 106 of the AND gate 13 also becomes rOJ, turning off the relay 15 via the relay driver 14. When relay 15 turns off,
Contact 16 is opened and transmission line 1 is disconnected.

At the same time, the contact 17 is turned on and the transmitting/receiving circuit 4 is connected to the resistor 1.
8, a power supply P5 is connected. At this time, in a node where a failure occurs in which the output signal 101 of the transmitter/receiver circuit 4 is always "0", the output signal 101 remains rOJ, so the transmission line 1 continues to be disconnected.

On the other hand, in a node where the transmitting/receiving circuit 4 is normal, the output signal 101 of the transmitting/receiving circuit 4 becomes "1", and the transmitting/receiving circuit 4. The relay 15 operates via the OR gate 12, the AND gate 13, and the relay driver 14, turning on the contact 16, and the transmission line 1 is connected again.

With this operation, only the node where the output signal 101 of the transmitter/receiver circuit 4 becomes abnormal can be disconnected from the transmission line 1, and the health of the transmission line can be ensured. Furthermore, this embodiment can be realized with simple hardware.

There is almost no cost increase and high reliability can be obtained.

〔Effect of the invention〕

According to the present invention, it is possible to completely eliminate a system down due to a failure of one node in the system, and the reliability of the system can be greatly improved.

[Brief explanation of the drawing]

FIG. 1 is a block diagram inside a node of one embodiment of the present invention, FIG. 2 is a partially detailed circuit diagram of one embodiment, FIG. 3 is an operation time chart of the present invention, and FIG. 4 is a diagram of the present invention. 1 is a diagram illustrating the configuration of a system to which the invention is applied; FIG. DESCRIPTION OF SYMBOLS 1... Transmission line, 3... Control circuit, 4... Transmission/reception circuit, 5... Line disconnection circuit, 9... Output abnormality detection circuit, 100... Transmission line signal, 102...・Received signal, 1
03...Kia Figure 1 I Figure Z

Claims (1)

[Claims] 1. In a contention type information communication system in which a transmission path is shared between a plurality of transmitting/receiving stations, an output abnormality that causes a system down of the information communication system is detected in the transmitting/receiving station, and the transmitting/receiving system is detected as an output abnormality. An information communication system characterized in that only a station is completely separated from the transmission path.