JPH03254249A - Multiplex transmission system - Google Patents

Abstract

PURPOSE:To reduce the transmission time from a transmission request to a return of a prescribed data and to attain efficient transmission by sending a data in response to a transmission request from a storage means to a multiplex node of a transmission request sender. CONSTITUTION:A transmission control means 30 stores a data inputted via a signal transmission line in advance to a storage means 30d and when a transmission request comes, a relevant data is read from a storage means 30d to apply data conversion and the result is sent to multiplex nodes 11-15, 21-25 having a transmission request. Thus, the multiplex nodes 11-15, 21-25 have only to send a transmission request to the transmission control means 30 to obtain a required data similarly in the case of the communication with the multiplex nodes 11-15, 21-25 of multiplex communication networks 10, 20. Thus, the transmission time from a transmission request to a return of a prescribed data is reduced and the data transmission is implemented efficiently.

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention relates to a multiplex transmission method (prior art) for transmitting data between multiple nodes connected to a plurality of networks. Conventionally, this type of multiplex transmission The system includes a microprocessor (CPU) that performs electronic processing control, a multiplex transmission control IC1 that performs transmission control of a multiplex communication network, a communication control circuit consisting of a transmitting/receiving buffer and an interface, etc., to create a multiple node. A plurality of the above-mentioned multiplex nodes are interconnected with a common signal transmission path (data bus) consisting of twisted pair electric wires, etc. to configure a loop-type multiplex communication network, and the above configuration has various responsiveness (for example, transmission speed CP
There is one that performs multiplex transmission by connecting with a transmission control unit having a gateway function using U.

In the above system, when a transmission request is made from a multiplex node connected to one multiplex communication network (receiving multiplex node) to a multiplex node connected to the other multiplex communication network (sending multiplex node), the The transmission control unit transmits the transmission request to the corresponding transmission multiplex node. When the return data corresponding to the transmission request is sent from the sending multiplex node, the return data is taken in and written into a buffer, and when the writing is completed, the return data is sent to the receiving multiplex node.

(Problem to be Solved by the Invention) However, in the above transmission system, when a multiplex node of one multiplex communication network obtains predetermined data from a multiplex node of the other multiplex communication network, it is always transmitted via the above transmission control unit. It is necessary to send a transmission request to the multiplex node of the other multiplex communication network via the transmission controller, and then receive predetermined data from the other multiplex communication network via the transmission control unit. There is a problem in that the dedicated time for the communication network becomes long, causing delays in other data transmissions.

The present invention has been made in view of the above problems, and it is an object of the present invention to provide a multiplex transmission method that can efficiently transmit data by shortening the transmission time from a transmission request to returning predetermined data. Objective (Means for Solving the Problem) In order to achieve the above objective, the present invention provides at least two multiplexed nodes connected to each other via a common signal transmission path, and a system in which each of the multiplexed nodes is connected. and transmission control means connected to the signal transmission paths and transmitting signals between the respective signal transmission paths, and each of the multiplex nodes In a multiplex transmission system in which predetermined transmission data is transmitted in response to a transmission request, the transmission control means includes a storage means for storing data manually input via the signal transmission path, and the data corresponding to the transmission request is stored in the storage means. A multiplex transmission method is provided in which data is transmitted from the transmission request source to the multiple nodes requesting the transmission.

(Function) The transmission control means stores data to be input via the signal transmission path in the storage means in advance, and when a transmission request is made, reads the corresponding data from the storage means, performs data conversion, and then sends the transmission request. Send to multiple nodes where there was. Therefore, each multiplex node can obtain the data it needs by simply sending a transmission request to the transmission control means in the same way as when communicating with multiplex nodes of other multiplex communication networks.

(Example) Hereinafter, an example of the present invention will be described in detail based on the drawings of FIGS. 1 to 3.

FIG. 1 is a block diagram showing the configuration of a multiplex transmission system according to the present invention. In the figure, each multiplex node 11-1
5.21 to 25 are the same configuration block, although they have different responsiveness (for example, transmission speed), so for convenience of explanation, the configuration of the multiplex node 11 will be described here as a representative.

In the multi-node 11, a CPU 1la performs electronic processing control.
In addition, a communication control circuit 11b consisting of a multiplex transmission control IC 1, a transmitting/receiving buffer, an interface, etc., which controls transmission of a multiplex communication network, is added.

The CPUs of each of the multiplex nodes 11-15 have the same responsiveness (for example, responsiveness with a high data transmission rate), and are connected to each other by a common multiplex transmission path (data bus) 10a via each communication control circuit. The network IO is configured, and each communication control circuit writes data from the CPU into the buffer at the time of transmission, and when the writing is completed, sends the buffer data to the data bus 10a via the interface. During reception, data input from the data bus 10a via the interface is written into the buffer, and when the writing is completed, the data in the buffer is sent to the CPU.

The CPUs of each of the multiplex nodes 21 to 25 have the same responsiveness (for example, a response that is slower than the data transmission speed of the CPUs of multiplexed nodes 11 to 15), and are connected to a common data bus 20a via each communication control circuit. are connected to form a network 20, and each communication control circuit sends and receives data signals to and from the CPU and data bus 20a, similar to the communication control circuits of the multiplex nodes 11 to 15.

Data buses 10a and 20a are each 100Kbps
As described above, multiple nodes 11-15.21-
25 transmits signals such as data frames and ACK signals via the data buses lOa and 20a.

The transmission control unit 30 has a CPU 30a for multiplex transmission control,
Communication control circuits 30b and 30c, an internal memory 30d, etc. are added. The communication control circuits 30b and 30c are
Each consists of a control IC, a buffer for each network that sends and receives data signals to and from the network, and an interface.
Writes data from a, and when writing is completed, sends the data in the buffer to network 10120 via the interface, and when receiving, writes data input from network 10.20 via the interface to the buffer. When the writing is completed, the data in the buffer is sent to the CPU 30a, and data signals are transmitted and received with the network 10.20.

The CPU 30a is connected to the network 10.20 via the communication control circuits 30b and 30c, and transfers the data fetched from the data buses lOa and 20a to each multiple node and stored in the network buffer into the internal memory 30d. The corresponding data is read from the internal memory 30d in response to a writing request and a transmission request from a multiple node connected to the other data bus, and is converted into a data signal corresponding to the responsiveness of the other network. It realizes a gateway function that returns data to multiple nodes. Therefore, signals can be transmitted between the buses of networks 10 and 20.

FIG. 2 is a schematic diagram showing an embodiment of the format structure of a data frame used in the multiplex transmission system of the present invention.

This data frame F has a data structure including a start bit, ID data, data, and ACK signal area.

The start bit is a specific bit indicating the start of frame F. Further, the ID data is composed of an address indicating the destination, an address indicating the own station, information indicating the data length of the data, and the like.

The ACK signal area consists of a plurality of bit areas, and a bit area corresponding to the address of the multiplex node is allocated to each multiplex node, and a bit area corresponding to the address of the multiplex node is allocated between each bit area. An ACK signal is arranged to be sent back when a frame is received, and the sending multiplex node uses the returned ACK signal to confirm normal reception.

Next, the reception processing operation of the transmission control unit in data transmission between each network will be explained. In this embodiment, a case will be described in which predetermined data is transmitted from the multiplex node 11 to the multiplex node 21.

When a data signal is received, the CPU 30a determines whether the data signal is received from the network IO based on the ID data of the data signal, etc. (step 101).
).

If the data signal is not received from the network 10, then it is determined whether the data signal is received from the network 20 (step 102). Furthermore, if the data is received from the network IO, it is determined whether the data signal is a signal from the multiplexed notebook 11 based on the ID data of the signal, etc. (step 103).
As a result, if the signal is not from the multiplex node 11, the reception processing operation is ended. Furthermore, if the data signal is a signal from the multiplex node II, the communication control circuit 30
The above received data is fetched from the network buffer of PCB and written to the internal memory 30d (Step 10).
4). Furthermore, the above received data is written to the network transmission buffer of the communication control circuit 30c (step 1).
08), the reception processing operation ends.

Further, in determining the data signal based on the ID data etc. in step 102, if the received data signal is not received from the network 20, the above-mentioned reception processing operation is ended, and the above-mentioned data signal is not received from the network 20.
0, the data signal is sent to multiple nodes 11
It is determined whether the request indicates a transmission request for (step 105).

Here, if the data signal does not indicate a transmission request to the multiplex node 11, the reception processing operation is terminated, and if the data signal is a transmission request to the multiplex node 11, it is stored in the internal memory 30d. The data corresponding to the multiplex node 11 is taken in from among the data being sent, and converted into a return data signal corresponding to the responsiveness of the network 20 (step 106), and the above return data signal is written to the network buffer of the communication control circuit 30c. (Step 107), the above reception processing operation is ended.

As a result, when the data writing to the network buffer is completed, the communication control circuit 30c transfers the data signal consisting of a frame structure such as ID data and a plurality of data in the network buffer to the multiplexer of the network 20 that has received a transmission request. It can be sent to node 11.

Therefore, in this embodiment, the data of the multiplex node 11 is constantly stored in the internal memory 30d of the transmission control unit 30 in accordance with changes in the data, regardless of transmission requests from the multiplex nodes 21 of other networks. When there is a transmission request from the multiplex node 21, the data corresponding to the transmission request can be read from the internal memory 30d and sent back to the multiplex node 21 that is the source of the transmission request without inquiring the multiplex node 11. In this case, it is no longer necessary for the transmission control unit to send a transmission request to a corresponding multiplex node and receive data from the corresponding multiplex node, and the return time for the transmission request can be shortened. The exclusive time for multiplexed communication networks can be shortened, and multiplexed nodes can obtain the data they need just by sending a transmission request to the transmission control unit, just as they communicate with multiplexed nodes in other multiplexed communication networks. .

In this embodiment, the internal memory is configured to store data from one multiple node, but the present invention is not limited to this. For example, the internal memory may have a storage area corresponding to each multiple node. It is also possible to store data from each multiple node, thereby allowing any multiple node in any network to efficiently receive data from other multiple nodes.

(Effects of the Invention) As explained above, the present invention provides signal transmission of at least two multiplexed nodes mutually connected via a common signal transmission path and at least two systems to which each of the multiplexed nodes is connected. and transmission control means connected to the signal transmission paths and transmitting signals between the respective signal transmission paths, and each of the multiple nodes transmits predetermined transmission data in response to a transmission request from any of the multiple nodes. In the multiplex transmission system for transmitting a signal, the transmission control means includes a storage means for storing data input through the signal transmission path, and transmits data corresponding to the transmission request from the storage means to the multiplex node that is the source of the transmission request. Since the data is transmitted, the transmission time from the transmission request to the return of the predetermined data can be shortened, and the data can be transmitted efficiently.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing the configuration of a multiplex transmission system according to the present invention, FIG. 2 is a schematic diagram showing an example of the format structure of a data frame used in the multiplex transmission system of the present invention, and FIG. 2 is a flowchart for explaining the reception processing operation of the transmission control section shown in FIG. 1. FIG. 10.20-...Network, 10a, 20a-...
Multiplex transmission line (data bus), 11~15.21~25・
...Multiple node, 30...Transmission control unit, lla. 30a-CPU, 30b, 30cm communication control circuit, 30
d...Internal memory.

Claims (1)

[Claims] at least two multiplex nodes connected to each other via a common signal transmission path; at least two systems of signal transmission paths to which each of the multiplex nodes is connected; and each signal transmission path connected to the signal transmission path. In a multiplex transmission method, the transmission control means transmits a signal between paths, and each of the multiplex nodes transmits predetermined transmission data in response to a transmission request from any of the multiplex nodes. A multiplex transmission system comprising: a storage means for storing data input through a transmission path; and data corresponding to a transmission request is transmitted from the storage means to a multiplex node that is the source of the transmission request.