JPH03184443A - Data contention control system - Google Patents

Abstract

PURPOSE:To eliminate the need for RS control for the contention control of data in a multi-drop line by sending data (1) to a slave station having no answer right, and taking the AND of data received at each node and data sent out from the slave station to be housed. CONSTITUTION:The slave station 29 sends out communication data corresponding to the attachment of the answer right by polling from a master station, and sends out the data (1) when no answer right is attached. A time slot counter 27 duplicates the received data from the time slot address of a communication frame on a multiplexing part 26, and inserts a result, in which the AND of the data and the data sent out from a line set part 24 is taken, to an original time slot address. Thereby, received data can be inserted to the time slot address as it is when no answer right is attached on the slave station 29. In a network, the communication data sent out from the slave station 29 having the answer right is transmitted to the master station.

Description

[Detailed Description of the Invention] [Summary] Regarding a data contention control method for controlling contention of data sent from multiple slave stations on a multi-drop line of a loop network system, R5 control is not required and R3 control is used to control data contention. With the aim of reducing the transmission delay time that occurs and simplifying system design, we have developed a multi-drop line for a loop network system that includes multiple slave stations and multiple nodes that accommodate the slave stations. In the data conflict control method, in which a master station controls a conflict in data transmitted from a station by giving a response right to one of the slave stations, each slave station transmits communication data in accordance with the granting of the reply right. The node is configured to send "1" data when it does not have the right to answer, and each node is provided with data sending means for sending the result of the AND of the received data and the data sent from the slave station it accommodates. configured.

[Industrial application field]

The present invention relates to a data contention control method for controlling data contention transmitted from a plurality of slave stations on a multi-drop line of a loop network system.

[Prior Art] FIG. 4 is a diagram illustrating a loop type network system.

In the figure, each node 42° to 42□ connected in a loop via a transmission line 41 includes a master station 43 and a slave station 44.
．． ．． 44□ are respectively accommodated, forming a multi-drop line of a loop type network.

In such a multidrop line, each slave station 44+, 4
The contention of data sent by 4z is controlled by R3 control. In other words, the selection of slave stations for multidrop lines is
In response to polling from the master station 43, a slave station that has data to send sets the R3 (transmission request) bit, and only the data sent by the slave station that has set the RS bit is placed in the communication frame.

[Problem to be solved by the invention]

FIG. 5 is a block diagram showing the configuration of a loop type network system in which communication devices are connected in multiple stages through links.

In the figure, each node 52° to 523 connected in a loop via a transmission line 51 includes a master station 53 and a slave station 54.
．． ~543 are accommodated, respectively.

However, node 52. ．． Each slave station 54 accommodated in 52□
．． ．． 54□ are multiplexers 56+, 5 facing from the multiplexer 551, 55□ via a digital multiplex line.
6z is connected, and modems 57, . 57□ is connected to the opposing modem 581 and 58□ via an analog line. Also, node 52. A slave station 54. is connected to the modem 5 via the local area network 59 and further from the modem 573 via the analog line.
83.

In such a system, the R3 control required for data contention control of each slave station must be designed in consideration of the increased transmission delay time due to multi-stage link connections.

That is, in a multi-drop line, it is necessary to set a transmission data waiting time according to each transmission delay time, which complicates the system design.

SUMMARY OF THE INVENTION An object of the present invention is to provide a data contention control method that eliminates the need for R5vI control of multidrop lines, reduces transmission delay time caused by R3 control, and simplifies system design.

[Means to solve the problem]

FIG. 1 is a block diagram of the principle of the present invention.

In the figure, the data contention control method prevents contention of data sent from the slave stations 11 on a multi-drop line of a loop network system comprising a plurality of slave stations 11 and a plurality of nodes 13 accommodating the slave stations 11. From master station to slave station 11
-9 is given the right to answer and controlled.

In the present invention, each slave station 11 is configured to transmit communication data in response to being granted the right to reply, and to transmit "l" data when it does not have the right to reply.

Each node 13 receives received data and accommodates the slave station 1.
The data transmitting means 15 is provided for transmitting the result of logical product of the data transmitted from 1.

[For production]

In the present invention, the slave station 11 that does not have the right to reply to the master station is
1'' data, and each node 13 sends out the result of the AND of the received data and the data sent from the slave station If it accommodates. As a result, the communication data sent from the slave station 11 in response to the granting of the reply right is transmitted to the master station via each node 13.

〔Example〕

Hereinafter, embodiments of the present invention will be described in detail based on the drawings.

FIG. 2 is a block diagram showing the configuration of the embodiment.

In the figure, a node 20 accommodating a slave station 29 includes a relay section 22 that interfaces with a transmission line 21, and a relay section 22 that interfaces with a transmission path 21.
a common unit 23 that performs multiplex control to insert data sent from the slave station 29 into communication frames sent and received with the transmission line 21 via the transmission line 21; It includes a line set section 24 that interfaces with data to be sent out.

The common section 23 includes a multiplexing section 2 that demultiplexes communication frames.
6, and a time slot counter 27 that inserts data sent from the line set section 24 into a communication frame received by the multiplex section 26.

Furthermore, the slave station 29 is configured to transmit communication data in response to the granting of the right to reply by polling from the master station, and to transmit rl and data when it does not have the right to reply. Furthermore, the node accommodating the master station (not shown) is connected to the slave station 2 in the communication frame.
The time slot for communication data from 9 to the master station is set to ``1''.
” data. That is, the configuration is such that when there is no slave station 29 that has the right to reply, data "1" is transmitted.

Although a pair of nodes 20 and a slave station 29 are shown in the figure, it is assumed that the network includes a plurality of similarly configured nodes 20, and each node 20 accommodates a plurality of slave stations 29. Further, data transmission is performed on a multi-frame line, and time slots for data from the master station to the slave station 29 and data from the slave station 29 to the master station are allocated separately. Furthermore, the time slot in which data from the slave station 29 to the master station is carried is shared by all slave stations 29 in order to efficiently utilize the area within the network.

Here, the correspondence between FIG. 1 and FIG. 2 will be shown.

The slave station 11 corresponds to the slave station 29.

Node 13 corresponds to node 20.

The data sending means 15 corresponds to a relay section 22, a common section 23, a multiplex section 26, and a time slot counter 27.

The line set section 24 is a standard component of the node 20.

The operation of the node 20 will be described below with reference to FIG. Note that the time slot position in a communication frame into which communication data to the master station is inserted is called a time slot address.

The communication frame is received by the multiplexing section 26 of the common section 23 from the transmission path 21 via the relay section 22 .

The time slot counter 27 copies data from the time slot address of the communication frame received by the multiplexing section 26, performs a logical product of this and the data sent out from the line set section 24, and uses the result as the original time slot address. Insert into.

In other words, even if communication data is suddenly sent from the housed slave station 29, this communication data can be inserted into the time slot address, and when the slave station 29 does not have the right to reply, the received data This configuration allows the time slot address to be directly inserted into the time slot address.

The communication frame from the multiplexer 26 is sent to the transmission line 21 via the relay unit 22 after data is inserted into the time slot address.

Within the network, the above-described operations are performed in each node 20, and communication data sent from the slave station 29 having the right to reply is transmitted to the master station.

〔Effect of the invention〕

As described above, according to the present invention, all that is required is to cause a slave station that does not have the right to reply to send rl and data, and to logically AND the data received at each node and the data transmitted from the slave station it accommodates. communication data can be sent to the transmission path.

Therefore, R3 control for controlling data contention in a multidrop line is not required, and it is possible to reduce transmission delay time caused by R3 control and to simplify system design.

[Brief explanation of drawings]

Fig. 1 is a block diagram of the principle of the present invention, Fig. 2 is a block diagram showing the configuration of an embodiment, Fig. 3 is a diagram explaining the operation of a time slot counter, and Fig. 4 is a block diagram showing the configuration of a loop type network. , FIG. 5 is a block diagram showing the configuration of a loop type network system in which communication devices are connected in multistage links. In the figure, 11 is a slave station, 13 is a node, 15 is a data sending means, 20.42.52 is a node, 2141.51 is a transmission line, 22 is a relay section, 23 is a common section, 24 is a line set section, 26 27 is a time slot counter, 29.44.54 is a slave station, 3.53 is a master station, 5.56 is a multiplexer, 7.58 is a modem, and 9 is a local area network. 1 Principle block diagram of the present invention Figure 1 Block diagram showing the configuration of an embodiment Figure 1 Diagram explaining the operation of the communication frame time slot counter

Claims (1)

[Claims] (1) A multi-drop line of a loop network system including a plurality of slave stations (11) and a plurality of nodes (13) accommodating the slave stations (11).
) from the master station to the slave station (1
1) In the data contention control method in which one of the slave stations (11) is controlled by giving the right to reply, each slave station (11) transmits communication data in response to the granting of the right to reply, and when it does not have the right to reply, it transmits communication data. 1'' data, and each node (13) has a data sending means (15) for sending the result of the AND of the received data and the data sent from the accommodated slave station (11). A data contention control method characterized by: