JPH0546148U - Redundant communication controller - Google Patents

Abstract

(57) [Abstract] [Purpose] When a communication station is newly connected to a duplex line, whether or not the connection is correctly made is checked prior to performing the actual communication operation. A frame transmitting / receiving means for transmitting and receiving a communication frame, and a used line setting means for setting line selection information as to which line of a duplexed line is used for a frame transmitted from the frame transmitting / receiving means, Line selection means for selecting one of the duplicated lines based on the line selection information set by the used line setting means, and when the communication station is first connected to the duplicated line, the frame transmission / reception means causes the line selection means. The line connection information is extracted by extracting the line selection information set in the frame first received via the line connection checking means for checking whether the line selection information matches the line selection information selected by the line selecting means. Be prepared.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a duplicated communication control device applied to a communication device connected to a duplicated communication line (network), and more specifically, a communication device connected to a duplicated communication line is correctly connected to the line. The present invention relates to a duplicated communication control device capable of identifying whether or not it has been performed.

[0002]

[Prior Art]

 In a distributed control device that requires high reliability, the control calculation unit (field control station) that is in charge of control and the communication line that connects them have a dual configuration, and when one fails, the other backs up. It has a duplex configuration that allows it. By the way, in such a device, assuming that the two duplicated communication lines are line 1 and line 2, respectively, it is necessary for each station to be correctly connected to line 1 and line 2, respectively.

If the connection to the redundant line is not correctly made at each station, or if a failure such as line disconnection occurs, failure analysis and restoration processing will not be performed correctly, which will have a serious effect. There is a fear. For this reason, conventionally, when the station was first connected to the duplicated line, the following procedure was used to recognize whether the connections to the line 1 and line 2 were made correctly.

That is, (a) the station newly connected to the line sets the line identification number in the frame and transmits the user data to another station. (B) The other stations receiving this data compare the identification number of the line on which they received the data with the identification number of the line set in the received frame, and send the comparison result. Return to the former station. (C) The transmission source station judges whether the connection to the line is correct based on the received comparison result, and outputs an alarm or the like if there is an error.

[0005]

[Problems to be solved by the device]

 However, according to this method, even if the comparison result is returned to the source station, the connection to the line of the other station may be incorrect, so the same operation is performed for other stations. Had to be repeated. Also, the same check had to be done for all stations connected to the network to ensure that the connection to the line at each station was absolutely correct.

The present invention has been made in view of the above circumstances, and automatically recognizes, when each station is connected to a network, whether or not the connection to a duplex line is correct. An object of the present invention is to provide a duplex communication control device capable of performing the above.

[0007]

[Means for Solving the Problems]

 The present invention that achieves such an object is a communication control device configured to perform transmission / reception (transmission) of data between a plurality of communication stations connected to a duplicated line, each communication station comprising: A frame transmitting / receiving means for transmitting and receiving a communication frame, a use line setting means for setting line selection information as to which line of the duplicated line is used for the frame transmitted from this frame transmitting / receiving means, and a duplicated line. Line selecting means for selecting one of the two lines based on the line selecting information set by the used line setting means, and the frame transmitting / receiving means for selecting the line selecting means when the communication station is first connected to the duplex line. The line selection information set in the first frame received via A line connection check means for checking whether or not the line selection information selected by the line selection means matches, and if the check results of the line connection check means match, a duplex line is used for each communication station. It is a duplex communication control device characterized in that it can participate in all communications.

[0008]

[Action]

 The line connection check means extracts the line selection information set in the frame first received by the frame transmission / reception means when the communication station is first connected to the duplex line, and the information is extracted. And the line selection information selected by the line selection means match. If the line selected by the line selection means and the used line selection information set in the frame match, it is judged that the communication station is correctly connected to the duplex line and if there is a mismatch. Determines that the connection is incorrect.

Then, only when it is determined that the connection is correct, the subsequent communication operation using the duplex line is permitted.

[0010]

【Example】

 The present invention will be described in detail below with reference to the drawings. FIG. 1 is a conceptual diagram showing the construction of an embodiment of the present invention. In the figure, the LAN is a duplex line (local area network) and is composed of two lines 1 and 2. ST1 and ST2 are a plurality of communication stations connected to the duplex line LAN, and correspond to, for example, a control station in charge of process control and an operator station for control operation and monitoring.

In each communication station ST 1, 1 is a frame transmitting / receiving means for transmitting and receiving communication frames, and 2 is a frame transmitted from the frame transmitting / receiving means 1 for two lines L 1 and L 2 forming a duplex line LAN. It is a used line setting means for setting which line is to be used. 3 is a line selecting means for selecting one of the duplicated lines L1 and L2 based on the line selecting information set by the used line setting means 2, 4 is a line connection checking means, and its communication station is duplicated When first connected to the line LAN, the line selection information set in the frame first received by the frame transmission / reception unit 1 via the line selection unit 3 and the line selection information selected by the line selection unit are It is configured to check for a match. Reference numeral 5 is a transmission / reception frame storage means for storing communication frames handled by the frame transmission / reception means 1.

Reference numeral 6 is a block generally showing the communication device, which sets and sends the station address of the other party and necessary data in the communication frame, and is stored in the transmission / reception frame storage means 5. The necessary data is extracted from the received communication frame, and predetermined data processing according to the contents is performed. The communication device 6 is configured to be able to start the subsequent communication operation only when receiving the permission signal output when the check results of the line connection check means 4 match.

The operation of the apparatus thus configured will be described below. The use line setting means 2 in the communication station already connected to the duplicated line LAN, when transmitting the communication frame, line selection information indicating which line is used to transmit to a specific area of the frame. To set. The line selection means 3 selects a line to be used in accordance with the line selection information set in the communication frame and sends the communication frame to the corresponding line, for example, the line L1 to execute communication.

The communication station ST will be newly connected to the duplex line LAN when a system is added. The duplex line LAN is normally set by the use line setting means 2 of each communication station so that one line, for example, L1 is used. In this case, the other line L2 is in a standby (standby) state in preparation for disconnection of the line L1.

The frame sending / receiving means 1 in the communication station ST which is first connected to the duplex line LAN receives the communication frame transmitted to the duplex line LAN via the line selecting means 3 at the beginning of communication. To do. At this time, the line connection check means 4 extracts the line selection information set in the frame received by the frame transmission / reception means 1, and extracts the line selection information and the line selected by the used line setting means 2. Check if the selected information matches.

As a result, if the two match, it is determined that the connection to the line is correctly made, and the communication device 6 is permitted to perform the communication operation using the communication line. On the other hand, if they do not match, it is determined that the line connection is incorrect, and an alarm indicating the error connection of the line is output, and the communication operation by the communication device 6 is not permitted.

The checking operation by the line connection checking means 4 is performed only when a communication station is newly connected to the duplex line. In the above description, the used line setting means 2 sets the line selection information to be used for all communication frames, but only the specific communication frame sets such used line selection information. You may do so.

[0018]

[Effect of the device]

 As described in detail above, according to the present invention, when a communication station is newly connected to the duplex line, it is checked whether the connection is properly made before the actual communication operation is performed. If a wrong connection is made, it can be identified immediately. Therefore, it is possible to prevent troubles (impact on failure analysis and recovery processing) when some failure occurs due to continued communication operation with incorrect connection.

[Brief description of drawings]

FIG. 1 is a conceptual diagram showing the configuration of an embodiment of the present invention.

[Explanation of symbols]

 LAN duplex line ST1, ST2 communication station 1 frame transmission / reception means 2 used line setting means 3 line selection means 4 line connection check means 5 transmission / reception frame storage means 6 communication device

Claims (1)

[Scope of utility model registration request] 1. A communication control device for transmitting and receiving (transmitting) data between a plurality of communication stations connected to a duplicated line, wherein each communication station transmits and receives a communication frame. The frame transmitting / receiving means for performing the above, the used line setting means for setting the line selection information as to which line of the duplicated lines is used for the frame transmitted from this frame transmitting / receiving means, and one of the duplicated lines are set. Line selection means for selecting based on the line selection information set by the used line setting means, and when the communication station is first connected to the duplex line,
The frame transmission / reception means extracts the line selection information set in the frame first received via the line selection means, and checks whether the line selection information matches the line selection information selected by the line selection means. And a line connection check means for enabling the respective communication stations to participate in the communication using the redundant line when the check results of the line connection check means match. apparatus.