JPH0319450A - Multi-point communication system - Google Patents

Abstract

PURPOSE:To attain communication with other normal slave station even when any slave station is faulty by providing a communication selecting means on a master station so as to select a communication opposite slave station for the communication. CONSTITUTION:The master station 1a uses a communication bus selecting circuit 4 to select a communication bus 5 connected to the slave station 2 and starts the communication. When the master station 1 communicates with one slave station 2, since the communication bus 5 of other slave station 2 is disconnected by the communication bus selecting circuit 4, the communication is not disturbed by the other slave station 2. Thus, even when any slave station 2 is faulty, the master station communicates normally with other normal slave stations and can recognize which slave station is faulty.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention is used in a multipoint communication system for communicating between one master station and a plurality of slave stations, and is particularly applicable to Also, a normal slave station relates to a multipoint communication method within a device that needs to communicate.

〔overview〕

The present invention provides a multi-point communication method for communicating between one master station and a plurality of slave stations connected to the master station via communication lines, in which the master station is provided with communication selection means, and communication By selecting a partner slave station for communication, even if one of the slave stations fails, it is possible to communicate with other normal slave stations.

[Conventional technology]

Conventionally, in a multi-point communication system in this type of device, as shown in FIG. 2, communication buses 5 from a plurality of slave stations 2 were connected to a single line at a master station l.

[Problem that the invention seeks to solve]

In the conventional multipoint communication method described above, when all the slave stations 2 are operating normally, only the slave station 2 with which the master station 1 wants to communicate returns a response. normal communication can be carried out. However, if one of the slave stations 2 fails and data is output to the communication bus 5 regardless of communication with the master station 1, there is a drawback that communication with other normal slave stations 2 becomes impossible.

An object of the present invention is to provide a multipoint communication system that eliminates the above drawbacks and allows normal communication with other normal slave stations even if one of the slave stations fails.

[Means for solving problems]

The present invention provides a multipoint communication system including one master station and a plurality of slave stations connected to the master station via communication lines, in which the master station selects the communication line of the slave stations with which to communicate. The present invention is characterized by comprising a communication line selection means for performing the following.

[Effect]

The master station selects a slave station to communicate with using the communication line selection means and performs communication.

Therefore, even if one of the slave stations fails, it is possible to communicate normally with other normal slave stations.

〔Example〕

Embodiments of the present invention will be described below with reference to the drawings.

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

This embodiment is a multi-point communication system that includes one main station 1a having a communication control device 3 and a plurality of slave stations 2 each having a communication control device 3a connected via a communication bus 5. 1a is equipped with a communication bus selection circuit 4 as a communication line selection means for selecting a communication bus 5 of a slave station with which to communicate, which is a feature of the present invention.

Next, the operation of this embodiment will be explained.

The master station 1a first selects the communication bus 5 connected to the slave station 2 with which it wants to communicate using the communication bus selection circuit 4, and starts communication. When the master station 1 is communicating with one slave station 2, the communication bus 5 of the other slave stations 2 is separated by the communication bus selection circuit 4, so that the communication is not interfered with by the other slave stations 2.

Therefore, even if one of the slave stations 2 fails, it is possible to communicate normally with other normal slave stations, and it is possible to know which slave station has failed.

〔Effect of the invention〕

As explained above, the present invention has the effect of preventing normal communication with the slave station from becoming impossible due to a failure of the slave station by providing means for selecting the communication line of the slave station on the master station side. Furthermore, it is possible to obtain the effect that the master station can determine which slave station has failed.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing an embodiment of the present invention. FIG. 2 is a block diagram showing a conventional example. DESCRIPTION OF SYMBOLS 1, 1a... Master station, 2... Slave station, 3, 3a... Communication control device, 4... Communication bus selection circuit, 5... Communication bus.

Claims (1)

[Claims] 1. In a multipoint communication system including one master station and a plurality of slave stations connected to the master station via communication lines, the master station is configured to communicate with the slave stations to which they are to communicate. A multipoint communication system characterized by comprising communication line selection means for selecting a communication line.