JPS63193631A - Communication system - Google Patents

Abstract

PURPOSE:To make it possible to send a telegram from a communication equipment with a lower priority level when a communication equipment with a higher priority level continuously outputs telegrams by dividing the priority level into two levels to constitute a communication system. CONSTITUTION:The communication equipment 2 (terminal 3) has the highest 1st priority level and continuously sends telegrams from the terminal 3 to a communication line 1. Although the communication equipment 4 (terminal 5) is lower in a 1st priority level as compared to the terminal 3, the terminal 5 is allowed to send a telegram to the communication line 1 almost once in N2 times by using a 2nd priority level every number N2 of interval times. A terminal 8 is lower in the first priority level as compared to the terminal 5, the terminal 8 is allowed to send a telegram to the line 1 almost once in N3 times by using the 2nd priority level every number N3 of interval times. The terminal 3 can be allowed to send a telegram to the communication line 1 once at least in N1 times.

Description

Detailed Description of the Invention 2 C.-7 Field of Industrial Application The present invention relates to a communication system in which a plurality of communication devices communicate with each other over a communication path to which the communication devices are connected.

BACKGROUND ART Conventionally, when a plurality of communication devices are connected on a communication path and the devices have priorities, a single priority level or a single priority level depending on the type of message on the communication path has been used. This is a priority added to the first priority level.

Problem to be Solved by the Invention However, in a communication system that has the priority order as described above, if a communication device with a higher priority level continues to send a large amount of messages to the communication channel for some reason, the communication device with a lower priority level There was a problem in that the communication device could no longer send messages to the communication channel.

The present invention has been developed in view of the above problems, and even if a communication device with a higher priority level continues to send messages to the communication path, a communication device with a lower priority level continues to send messages.

The purpose is to provide a communication method that allows communication.

Means for Solving the Problems In order to achieve the above object, the present invention divides the priority levels into two hierarchies, with the first priority level being the priority level of each communication device connected to the communication path, and the second priority level being the priority level of each communication device connected to the communication channel. Each communication device is arranged in the order of the first priority level, divided into groups, and prioritized in that order, and when the frequency of use of the communication channel becomes extremely high, the number of times is set for each second priority level. Set the second priority level to the first priority level at intervals equal to that number of times.
shall be used in addition to the priority level of

Effects of the present invention By configuring a communication system having two priority levels as described above, even if a communication device with a higher priority level continues to send messages to a communication channel, communication with a lower priority level is transmitted. The device will be able to send messages.

The embodiment diagram is a block diagram showing a communication system in an embodiment of the present invention. In the figure, 1 is a communication path to which a terminal (embedded type) 8 and a terminal 35 are connected via communication devices 2 and 4, and the terminal 8 is composed of a communication function 6 and a terminal function 7.

The communication system of this embodiment configured as above will be explained with reference to the drawings. The communication device 2 (that is, the terminal 3) has the highest first priority level and continues to send the message received from the terminal 3 to the communication channel. Communication device 4 (
In other words, terminal 6) has a first priority level lower than terminal 3, and similarly tries to send the message received from terminal 5 to the communication channel, but since terminal 3 has a higher priority level, the message is initially sent. cannot be sent. However, by using the second priority level for each interval value (N2), the terminal 6 can send a message to the communication channel approximately once every N2 times.

Terminal 8 has a first priority level lower than terminal 5 and attempts to send a message to the communication channel, but terminal 3. The message cannot be sent because the priority level of terminal 6 is higher. however,
Terminal 8 also uses the second priority level for each interval value (N3).

By doing this, it is possible to send a message to the communication channel approximately once every N3 times. Since these two terminals use the second priority level, terminal 3 cannot continue to send messages, but since the interval number is N1, at worst it will send a message to the communication channel once every N1 times. can.

A specific example of the above message sending situation is shown in the table. In this table, A
Although terminals from to P are assumed, only terminals A, F, and I actually attempt to send messages. These terminals are beginning to send messages at the same time. The sequence numbers of each message start from 1. On time axes 8 and 9, competition occurs at the second priority level. According to this table, communication device A has an interval value of 2.
At worst, Gai sends out a telegram once every two times. Communication device F has an interval value of 4 and sends a message once every four times. The communication device ■ has an interval value of 8, and the communication device
Sending a return message.

(＞゛人对ii、white) Go to 7 - Effects of the Invention As mentioned above, even if a communication device with a higher priority level continues to send messages to the communication path, it will still be transmitted to a communication device with a lower priority level. A level communication device can realize a communication system that can send messages over a communication path.

[Brief explanation of the drawing]

The figure is a block diagram showing a communication method in an embodiment of the present invention. 1... Communication channel, 2, 4... Communication device,
3,6゜8...Terminal, 6...Communication function, 7...Terminal function. Name of agent: Patent attorney Toshio Nakao and one other person Bt
s end (built-in type)

Claims (1)

[Claims] In a communication path where multiple devices with communication functions are connected, if these devices have priorities regarding message transmission, the priorities are divided into two levels, and in normal communication, the first level (single or (composed of multiple blocks), and if communication is not possible due to inferior priority, the first method is created by arranging the devices in order of the first priority level and dividing them into multiple blocks. Communication is performed using a second priority level that is higher than the priority level, and after that, the second priority level is not used until communication is performed a predetermined number of times for each second priority level, and communication is performed using the first priority level.
A communication method that allows devices with a low first priority level to communicate even when a communication path is frequently used by communicating only with a first priority level.