JPH05153115A - Communication network - Google Patents

Abstract

PURPOSE:To perform a communication between a normal slave station present on lower-order than a faulty station and a master station by specifying the faulty station in a high-order station just higher than the faulty station at the time of the occurrence of the fault in an arbitrary slave station. CONSTITUTION:When a slave station E is in fault and the transmission request for transmission to the high-order line of a slave station F is fixed to be 'present', a slave station C being just higher-order than the faulty station excludes transmission information received from the low-order line from the object of selection of the transmission information to be transmitted to the high-order line and simultaneously transmits an NM signal 101 indicating that a connection with the master station can not be connected to the slave station E. On the other hand, the slave station H immediately transmits an MS signal 301 to the old high-order line, then decides the slave station F to be a new high-order station according to the priority and executes the processing of transmitting a SM signal 302 to the new high-order line. Also, the slave station F transmits the reception data of the high-order line as transmission data to the slave station H and then adds the reception data from the slave station H to the object of the selection of the transmission data to the high-order line.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is used for communication control between a master station and each slave station in a hierarchical communication network composed of one master station and a plurality of slave stations. The present invention is
The present invention relates to a communication network that enables communication between a master station and a normal slave station that is subordinate to a failed station.

[0002]

2. Description of the Related Art One type of communication network, for example, FIG.
As shown in FIG. 1, there is known a configuration including one master station, a plurality of slave stations, and a plurality of lines connecting the master station and the plurality of slave stations to each other. A is a master station provided with a supervisory control device, 201 is a direct connection line between a master station and a slave station, B,
C, D, E, F, G, H, I, J are slave stations, 202 is an inter-slave line, and master station A is a slave station B, C, D, E, F, G via lines 201, 202. , H, I, J.

FIG. 4 is a diagram for explaining the configuration between adjacent slave stations. 301 is an MS signal, 302 is an SM signal,
, Indicates the priority. Upper station is lower station MS
The lower station sends the SM signal 302 to the upper station.

Each station recognizes the type of route by a combination of a transmission signal and a reception signal in a line connected to itself. [Table 1] shows the type of each route.

Each slave station first transmits the received data of the upper line as it is as the transmitted data of the lower line, and then,
Among the received data of each lower-order line, the received data whose transmission request indicates "Yes" is sent as the upper-line send data, and then the independent line does not send or receive the data except the SM signal and the MS signal. To process.

The priority of each slave station represents the order of selecting a new upper line when the upper line is disconnected or when an SM signal is received from the upper line. At this time, each slave station first immediately sends an MS
A signal is sent, then a new upper line is determined according to the priority, and then processing is executed to send an SM signal to the new upper line.

With such processing, the communication paths for communication between the master station and the slave stations in the network shown in FIG. 3 are connected as shown in FIG.

Next, in the unlikely event that one of the slave stations, for example, the slave station E shown in FIG. 1 fails, and the transmission request to be transmitted to the upper line of the slave station E is fixed to "present", the slave station immediately above the failed station is fixed. C excludes the transmission information received from this lower line from the selection target of the transmission information to be transmitted to the upper line, and the slave station E
Since the transmission request of is fixed to “Yes”, the failure that all slave stations cannot send the transmission information to the master station is avoided.

[0009]

[Table 1]

[0010]

In the above-mentioned conventional communication control system, when a failure occurs, the transmission information of the normal slave station H in addition to the malfunctioning slave station E is excluded from the selection target. There is a problem that communication with the main station becomes impossible.

The present invention solves such a problem, and an object of the present invention is to provide a network capable of communicating between a master station and a normal slave station subordinate to a faulty station.

[0012]

According to the present invention, in a communication network in which one master station and a plurality of slave stations are connected by a line, and the master station is the highest hierarchy, in each of the slave stations, First transmitting / receiving means for generating and transmitting / receiving route establishment information for determining the relationship between adjacent slave stations, and second for transmitting / receiving a transmission request indicating presence / absence of transmission information from the slave station to the master station Transmission / reception means, selection means for selecting the transmission information of the slave station whose transmission request indicates "present" as information to be transmitted to a higher level, and "absence" while the transmission request of any slave station is fixed to "present" When a failure occurs, the higher station immediately above the failure station identifies the failure station, ignores the transmission request of the failure station, and all the slave stations cannot communicate with the master station due to the failure. Obstacle avoidance to avoid things Characterized by comprising a stage.

It is preferable that each of the slave stations is provided with third transmitting / receiving means for generating and transmitting / receiving second route establishment information for notifying the slave stations excluded from the selection that the slave stations cannot be connected to the master station. ..

[0014]

When a failure occurs in which the transmission request of any slave station is fixed to "Yes" and does not return to "No", the failure station is specified in the upper station immediately above the failure station and the transmission request of the failure station is made. To avoid that all slave stations cannot communicate with the master station due to a failure. Further, when the transmission information of the slave station whose transmission request indicates “present” is selected as the information to be transmitted to the upper layer, the slave station excluded from the selection target is notified that the slave station cannot be connected.

As a result, the communication between the master station and the normal slave station below the faulty station can be restored.

[0016]

Embodiments of the present invention will now be described with reference to the drawings. FIG. 1 is a diagram showing network configurations of an embodiment of the present invention and a conventional example.

In the embodiment of the present invention, one master station A and a plurality of slave stations B, C, D, E, F, G, H, I and J are connected by a line, with the master station A as the highest level. The first hierarchical layer is used to generate and transmit route establishment information to each of the slave stations B, C, D, E, F, G, H, I, and J to determine the relationship between adjacent slave stations. Transmission / reception means and slave station B,
The second transmission / reception means that generates and transmits / receives a transmission request indicating the presence / absence of the transmission information from each of C, D, E, F, G, H, I, and J to the main station A, and the transmission request is “present”. The selection means for selecting the transmission information of the slave station indicating "as the information to be transmitted to the upper layer" and the failure when the transmission request of any slave station is fixed to "present" and not returned to "no" occurs. The upper station immediately above the station specifies the faulty station, ignores the transmission request of the faulty station, and causes all the slave stations B due to the fault,
C, D, E, F, G, H, I, and J are provided with failure avoidance means for avoiding the inability to communicate with the master station A, and the slave stations B, C, D, E, F, G, and H, I, and J
For each of the slave stations excluded from the selection target, master station A
And third transmission / reception means for generating and transmitting / receiving second route establishment information for notifying that the connection cannot be established.

Next, the operation of the embodiment of the present invention thus constructed will be described.

When the slave station E breaks down and the transmission request to be transmitted to the upper line of the slave station F is fixed to "Yes", the slave station C immediately above the failed station receives the transmission from this lower line. The information is excluded from the selection target of the transmission information to be transmitted to the upper line, and at the same time, the slave station E is transmitted with the NM signal 101 indicating that the master station cannot be connected. At this time, the slave station E first sends the NM signal 101 to the old upper line immediately, then determines the slave station H as the new upper station according to the priority, and then executes the process of sending the SM signal 302 to the new upper line. To do.

On the other hand, the slave H firstly immediately sends the MS signal 301 to the old upper line, then determines the slave F as the new upper line according to the priority, and then sends the SM signal 302 to the new upper line. To execute.

Further, the slave station F first recognizes the slave station H as a lower station according to [Table 2], then transmits the received data of the upper line as it is as the transmission data to the slave station H, and then the received data from the slave station H. Add to the selection of data to be sent to the upper line. This situation is shown in FIG.

Here, even if the transmission request of the slave station E remains "present", the slave station H is excluded from the selection target of the transmission information to the upper line by performing the same operation as the slave station C. ..

[0023]

[Table 2]

[0024]

As described above, according to the present invention, the route establishment information indicating whether the slave station can connect to the master station is generated and transmitted / received, and the slave station excluded from the selection targets is connected to the master station. By notifying that the failure is not possible, there is an effect that the communication between the master station and the normal slave station under the faulty station can be restored.

[Brief description of drawings]

FIG. 1 is a diagram showing network configurations of an embodiment of the present invention and a conventional example.

FIG. 2 is a diagram illustrating a situation of avoiding a failure in the embodiment of the present invention.

FIG. 3 is a block diagram showing a configuration of a conventional example.

FIG. 4 is a diagram showing a configuration between adjacent slave stations in a conventional example.

[Explanation of symbols]

 101 NM signal 201 Master-slave direct connection line 202 Slave-station line 301 MS signal 302 SM signal A Master station B, C, D, E, F, G, H, I, J Slave station

Claims (2)

[Claims] 1. In a communication network in which one master station and a plurality of slave stations are connected by a line, and the master station is the highest level in a hierarchical communication network, each slave station determines the relationship between adjacent slave stations. First transmitting / receiving means for generating and transmitting / receiving the route establishment information for transmitting, and second transmitting / receiving means for generating and transmitting / receiving a transmission request indicating the presence / absence of transmission information from the slave station to the master station, the transmission request When there is a failure that selects the transmission information of the slave station that indicates "Yes" as the information to be sent to the upper level, and the transmission request of any slave station is fixed to "Yes" and does not return to "No" A failure avoidance means for identifying a failure station in a higher station immediately above the failure station, ignoring the transmission request of the failure station and avoiding that all the slave stations cannot communicate with the master station due to a failure. Specially equipped Communication network to be. 2. Each of the slave stations is provided with a third transmitting / receiving means for generating and transmitting second route establishment information for notifying a slave station excluded from selection that the slave station cannot be connected to the master station. The communication network according to claim 1.