JPH0247945A - Network control system - Google Patents

Abstract

PURPOSE:To realize two kinds of network control systems such as the contention system and the polling system and to obtain a network with a high transmission efficiency by providing two transmission lines, using the one for data communication including the control in the contention system and using the other for transmitting and receiving a polling/selecting signal. CONSTITUTION:In the network system, the 1st transmission line 1 is used usually, the communication is applied by the contention system and when the transmission request in a master station 3 is increased, the master station 3 sends an own station node address + dummy data to the 2nd transmission line 2 and the system of the master station 3 is changed from the contention system into the polling system. Thus, a slave station uses a carrier detection section 13 to detect a data flow in the transmission line 2 to stop the function of a selection section 13. The detection section 13 is switched from this point of time into a polling/selecting signal transmission reception circuit section 14 and the master station 3 starts the transmission request and the inquiry of the reception enable to the circuit section 14 of a transmission station and applies the communication in the polling system.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a network control system, and particularly to a network control system for a specific transmission line commonly used between a master station and a plurality of slave stations.

[Conventional technology]

Conventionally, the contention method and poll link/selecting method have been widely used as this type of network control method. The contention method is a method in which a transmitting station that has a transmission request detects an empty transmission path, issues a transmission request, and starts transmitting data from the moment it receives a receivable signal from the receiving station. When a transmission request is issued from a station, priority usage rights are given according to predetermined rules, and the above rules are created so that each transmitting/receiving station is equally given the right to use the transmission path. On the other hand, in the polling/selecting method, the control station normally sends transmission requests to each station in turn and determines whether or not the data can be received.If there is a transmission request, permission is given to the transmission, and if the data can be received, the data is transmitted. The right to use the transmission path is managed by the control station.

[Problem to be solved by the invention]

In network control using the conventional contention method described above, the master station and slave stations have equal rights to use the transmission path, so when the master station's line usage rate is high, it takes longer for the master station to acquire the right to use the line. The drawback is that it takes a long time, prevents efficient network operation, and reduces transmission efficiency. In addition, in network control using the conventional polling/serenoting method described above, the time to acquire the right to use the line during communication is determined by the time it takes for the main station or control station to come to poll. When there are many requests, the waiting time increases even if the load on the communication line is low, and the line utilization rate decreases, resulting in poor transmission efficiency.

[Means to solve the problem]

The network control method of the present invention connects each station with two common transmission paths in a communication network system consisting of one master station and a plurality of slave stations, and one transmission path is used for contention control and data communication. By using the other transmission line as a transmission line for controlling the polling/selenoting method and as a transmission line for selecting between the polling/selenoting method and the contention method, It is configured by having two network control methods, a contention method and a contention method.

〔Example〕

Next, the present invention will be explained with reference to the drawings.

FIG. 1 is a relay system diagram of an embodiment of the present invention, in which there are two independent transmission lines, namely, a first transmission line 1 which handles data communication transmission.
and a second transmission line 2 which is in charge of transmitting and receiving polling/serenoting signals, and is composed of a master station 3 and slave stations 4 to N, each of which has a communication control device. are doing.

FIG. 2 is a block diagram of the communication control devices for the master station and slave station in FIG. 1. In FIG. Transmission/reception control section 12. Carrier detection unit 13. It is composed of a polling/selecting signal transmitting/receiving circuit section 14.

In the network system shown in Figure 1, communication is normally performed using the contention method using the first transmission path 1, but when the number of transmission requests at the main station 3 increases and the waiting time increases, contention The process of shifting from system control to polling system control will be explained. When main station 3 shifts from contention method to polling method control, main station 3
transmits own node address dummy data to the second transmission line 2. The slave station learns from the carrier detection unit 13 that data has flowed to the second transmission path 2, and detects the carrier detection unit 1.
Stop function 3. From this point on, the carrier detection section 13 switches to the polling/selecting signal transmission/reception circuit section 14 to issue transmission permission. At the same time, the main station 3 transmits the polling/selecting signal transmitting/receiving circuit section 14 of the transmitting station.
Starts making inquiries regarding ``request to send'' and ``receipt availability.''

When the main station 3 returns from the polling method to the contention method, it sends a polling/serenoting method stop signal to all slave stations in broadcast format over the second transmission line 2, and each slave station transmits the polling/selecting signal. The transmitting/receiving circuit section 14 is disconnected and the carrier detecting section 13 is activated.

〔Effect of the invention〕

As explained above, the present invention provides two transmission lines,
By using one side for data communication including contention mode control and the other for polling/selecting signal transmission/reception, two types of network control methods can be realized: contention mode and polling mode. This has the effect of achieving high transmission efficiency in the network even when the load is low and communications are concentrated between specific stations.

[Brief explanation of the drawing]

FIG. 1 is a diagram of a relay system according to an embodiment of the present invention, and FIG. 2 is a block diagram of a communication control device in a master station and a slave station. DESCRIPTION OF SYMBOLS 1...First transmission path, 2...Second transmission path, 3...Main station, 4-N...Slave station, 10...Communication control device, 11
. . . Transmission/reception circuit unit for data communication, 12 . . . Transmission/reception control unit, 13 .

Claims (1)

[Claims] In a communication network system consisting of one master station and a plurality of slave stations, each station is connected by two common transmission paths, and one transmission path is used as a transmission path for control and data communication in contention, By using the other transmission path as a transmission path for controlling the polling/selecting method and as a transmission path for selecting between the polling/selecting method and the contention method, it is possible to control the polling/selecting method and the contention method. A network control method characterized by having a network control method of a method.