JPS6281843A - Data transmission system - Google Patents

Abstract

PURPOSE:To prevent the message stagnation by placing a transmission right to a terminal device when number of times of token reception reaches the number of times set in response to the transmission frequency of plural data terminal devices connected to a bus. CONSTITUTION:Each reception section 12 of plural data terminal devices DT (only one is shown in figure) connected to a data bus 100 via an isolation coupler 11 supervises the bus 100. When the transfer destination of a reception signal is addressed to the own terminal device, a message is sent to a peripheral device P. Then a token signal is outputted to a token adjusting circuit 14 and when the number of arrivals reaches a preset number of times N in a priority counter 15, a message is extracted from the peripheral device P and sent to the bus 100 via a transmission section 19 and the isolation coupler 11 together with a token 17. When the message to be sent does not exist and the number of received token is N or below, only the token 17 is sent to the bus 100. Thus, the number of times N is set depending on the degree of transmission frequency to improve the utilizing efficiency of the bus.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a data transmission system, and more particularly to a data transmission system that introduces priority to each data terminal of Buskozo's token passing system used in a local area network. .

(Conventional technology) In the conventional token passing data transmission method,
Tokens are moved according to the token order of each data terminal, which is obtained in advance when each data terminal is started (e.g., according to the order in which the power is turned on for each data terminal, etc.), so the transmission right also goes around V&/I accordingly. . This means that each data terminal has an equal opportunity to be able to transmit data.

Therefore, if there is a data terminal with a low transmission frequency and a data terminal with a low transmission frequency, the transmission right will be passed to these two terminals in the same way, so the terminal with transmission congestion and the transmission rA
This creates a constraint that a large number of terminals receive the same number of transmission rights.

(Problems to be Solved by the Invention) The problems in the conventional technology that the present invention attempts to solve are as described above. (2) are given equally, resulting in data terminals congested with message transmission and data JZ terminals being idle, resulting in poor mobility as a data transmission system.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a data transmission system that solves the above-mentioned drawbacks.

(Determined Means to Solve All Problems) The data transmission system of the first invention of the present invention is a data transmission system based on token passing, in which a message is sent every time the number of tokens received from the transmission medium reaches a predetermined number of times. If there is a message to be transmitted from the data terminal when all of the tokens are received and the number of receptions at that time is a predetermined number of times among a plurality of data j1 terminals that are capable of transmitting the data, the message and the token are and when there is no message to be transmitted, only the token is transmitted to the transmission medium, and when all the tokens are received and the number of receptions is less than a predetermined number of times, only the token is transmitted to the transmission medium. Prepared and configured.

The data transmission device of the second uninvented invention is a data transmission device using token passing, in which all tokens are received from a transmission medium, and when the number of receptions at that time is a predetermined number of times, the message to be transmitted is sent. If there is no message to send, then only the token, if the token is received and the number of receptions is less than a predetermined number of times, only the token, Among the data terminals comprising all the token control means for transmitting to the transmission medium, at least one data terminal having a different predetermined number of times is provided.

A data terminal according to a third uninvented invention is a data terminal used in conjunction with a transmission medium of a data transmission device using token passing, which receives a token from the transmission medium and the number of receptions at that time is determined in advance. When the number of times the message is sent is the same as the token, when there is no message to be sent, only the token is sent, and when the token is received, the number of receptions is a predetermined number of times. If the number is less than 1, the token control means is configured to transmit only the token to the transmission medium.

(Example) Next, the present invention will be described in detail with reference to a practical example. Figure 1 is a block diagram showing an overview of the present invention. Figure 2 is a block diagram showing the structure of an embodiment of the present invention.
The figure shows an example of the data flow on the token bus. Each token has the right to send a message.Every two tokens has the right to send a message.Work Talk 73
FIG. 3 is a configuration diagram showing what is authorized to send a message for each session.

An outline of an embodiment of the present invention will be explained.

Referring to FIG. 1, an overview of an embodiment including the present invention includes a data bus 100 and a data terminal D connected to the data bus 100.
Tl-D'I', and peripheral devices connected through these that operate interfaces)', -1'Il.

Each data terminal has a predetermined order N(
It has a structure that allows you to send 1g messages only when you receive a token (hereinafter referred to as N) and when you are a friend, and when N = 1, you can send a token for every token received, and when N = 2, you can send a token twice. When each reception is set to = 3, the right to send a message is given to the data terminal each time a token is received three times.

The data terminal is configured in such a way that the smaller the effort 9N, the easier it is to send the message, i.e. the higher the priority. Therefore, by setting Ni smaller for data terminals that send messages frequently, and increasing N for data terminals that send messages less frequently,
To provide an entire data transmission system capable of preventing congestion in data transmission and completely preventing inefficiency in data transmission such as no message being sent even if all TE transmission rights are granted.

Signals or data on the data bus 100 generally consist of messages and tokens representing data terminals, and are constantly monitored by a bus monitoring section inside each data terminal. The data terminal receives the data as the transfer destination, and in case of emergency, transmits the message to the peripheral device. On the other hand, when the next token is received 1g after the previous data transmission, when a transmission message is received from a peripheral device, the transmission message and token are sent to the data bus 100 as all data (g L
When there is no message sent from the peripheral device, only the token is sent to the data bus 100 as one-word money transfer data.

In this case, a priority counter that calculates the number N of tokens received is placed in the data terminal, and the counter is reset every time N tokens are received. The device is ready to send messages.

Next, please refer to Fig. 3, Fig. 4 (a), (b) and (C) for the flow of token Meyu Kanekura data on the data bus (data flow on the token bus) in the embodiment of the present invention. I will explain.

Figure 3 shows the flow structure on the token bus.
Generally, one piece of data is discarded from the message M and the token T, which include the forwarding destination of the message at the beginning. Each piece of data is received by the data terminal to which the message is transferred, and if that data terminal has the right to send the message and the message to send, the message and token are sent onto the bus, giving the data terminal the right to send the message. Even if there is no message transmission right, if there is no message to send, only a token is sent on the bus, which is obtained in advance at the time of starting each data terminal (for example, when each data terminal is powered on, the Ilt'i According to the token order of each data terminal (e.g.), the corresponding data terminal receives the token. Even if only all tokens are received, the same operation as in the case of receiving the above message and token is performed.

Focusing on each data terminal, the entire transmission/reception situation of each data terminal when N=1 to 3 will be explained with reference to FIGS. 4(a) to 4(C). FIG. 4(a) shows a case where N=1, transmission and reception data 201 to 204 are not transmission and reception data, respectively, and transmission and reception data 201 to 203 are both transmission and reception data of the data terminal concerned, and the transmission and reception data 201 to 203 are message superiors. Transmission and reception of the data terminal (i-data 204 indicates the case where the transmission data does not include a message for which the transmission fee is to be paid).

FIG. 4(b) shows the case where h = 2, and the transmitted and received data is 30.
The transmitted and received data 301 and 303μ indicate the case where both the transmitted and received data of the data terminal include a message, and the transmitted and received data 305 indicates that even if the data terminal has the right to transmit messages, neither of the transmitted and received data includes a message. Indicates that there is no transmitted/received data 302.
304 indicates a case where the data terminal does not have the right to send a message.

FIG. 4(C) shows the case where N=3, and the transmitted/received data is 40.
1 to 405, and sent/received data 401 and 404 indicate if the data terminal in question does not have the right to send a message.

As mentioned above, as M on the token bus increases, the transmission opportunities decrease and the priority decreases, and as N decreases, the priority increases. By doing so, it is possible to average out the degree of traffic congestion and slowness of messages transmitted by each data terminal.

Next, a non-inventive embodiment will be explained focusing on its configuration and operation.

Referring to FIG. 2, the present example includes a data bus 100, data terminals L)T, and peripheral equipment P. Further, the data terminal L)T includes an insulated Kagura 11, a receiving section 12,
Bus monitoring section 13, talk/adjustment circuit 14, priority counter 15, token generation section 17, and transmission selection section 18
and a transmitting section 19.

The data signal of the data bus 100 is constantly supplied to the receiving section 12 through the insulating coupler 11, and the bus monitoring section 13 determines whether the received terminal is the message transfer destination.
The message received from the receiving unit 12 is output to the peripheral device P based on the result.

At the same time, the token adjustment circuit 14 outputs the signal g of the token, converts it into a pulse, and inputs it to the priority counter 15 which outputs one pulse in response to N pulses. 15 to N pulses or N
One full pulse is output for each token and inputted to the transmission selection section 18, where the message obtained from the peripheral device P is sent to the transmission section. Here, each time one pulse is sent to the token generation section 17 for each token received from the token adjustment circuit 14, the token is sent through the transmission selection section 18 to the transmission section 19, and the message and token are integrated. The signal is transmitted from the transmitter 19 to the data bus 100 through the entire insulating coupler 11 .

Further, when there is no message to be transmitted or when only the pulse corresponding to the token is applied to the token generating section, only the token is transmitted from the transmission selecting section 18 to the data bus 100 through the transmitting section 19 and the insulating cable Ilk.

In this way, it becomes possible to transmit and receive data as shown in the flow of data on the nine token buses described in the explanation of FIGS. 4(a) to 4(c).

(Effects of the Invention) As explained in detail above, the uninvented data transmission method has a structure in which each data terminal receives a predetermined number of tokens and can send only 9 messages to a friend. Since message transmission rights can be given to data terminals that send messages frequently and to data terminals that send messages infrequently according to their respective sending frequencies, data terminals that are busy sending messages and data terminals that are idle can no longer coexist, and the data bus can be It has the effect of being used effectively.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing an overview of the invention, FIG. 2 is a block diagram showing the configuration of an embodiment of the invention, FIG. 3 is a block diagram showing an example of the flow of data on the token bus, and FIG. figure(
a), (b) and (C) are one side tone of the data flow on the token bus of the present invention, where each token has the right to send a message, and the right to send a message once every two tokens. Ro11...Insulating coupler, 12
...Receiving section, 13...Bus monitoring section, 1
4... Token adjustment circuit, 15... Priority counter, 17... Token generator, 18
...Transmission selection section, 19...Transmission 1g section. DT in the 1st, Tateki 100: Te'°-Tabus Fig. 2

Claims (1)

[Claims] 1. In a data transmission system using token passing, the token is selected from among a plurality of data terminals that are capable of transmitting a message every time a predetermined number of tokens are received from the transmission medium. and when the number of receptions at that time is a predetermined number of times, if there is a message to be transmitted from the data terminal, this and the token, and if there is no message to be transmitted, only the token, A data transmission method comprising: transmitting only the token to the transmission medium when the number of receptions of the token is less than a predetermined number of times when the token is received. 2. In a data transmission device using token passing, when a token is received from a transmission medium and the number of receptions at that time is a predetermined number of times, the message to be transmitted, if any, and the token are transmitted. If there is no message, just the token,
A data terminal comprising token control means for transmitting only the token to the transmission medium when the number of receptions of the token is less than a predetermined number of times. A data transmission device comprising at least one different data terminal. 3. In a data terminal used in connection with a transmission medium of a data transmission device using token passing, when a token is received from the transmission medium and the number of receptions at that time is a predetermined number of times, the message is transmitted. When there is, this and the token, when there is no message to be sent, only the token, when the token is received, if the number of receptions is less than a predetermined number of times, only the token, A data terminal comprising means for controlling a token transmitted to a transmission medium.