JPH0523003Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention relates to a token passing bus type communication device which is duplexed by two buses, and particularly relates to an improvement for detecting incorrect bow connection. .

(Prior art) FIG.
2, which is known from Publication No. 170249 (Japanese Patent Application No. 57-52925) etc.
FIG. 2 is a configuration block diagram of a multiplexed token passing bus type communication device. In the figure, BUS1 is a first communication line, BUS2 is a second communication line, and the communication lines are made redundant. All of S1 to S4 are redundant communication stations, and all have the same configuration. The communication stations S1 to S4 have input/output units Bus1 and Bus2 corresponding to communication lines BUS1 and BUS2, and are connected to each other by a bus.

In a device configured in this way, the two redundant systems are used alternately, with one being the active side and the other being the standby side, and when a failure occurs, the failed bus is not used and the normal bus is replaced. Communication takes place using only

The right to use the communication line BUS is called a token.
Tokens are circulated between communication stations S1 to S4 to control communication initiative.

(Problem that the invention attempts to solve) Since the communication lines BUS1 and 2 and the input/output parts Bus1 and 2 do not necessarily have a strict correspondence relationship, they operate.
Even if an erroneous connection is made to the communication station S3 shown in FIG. 4, it cannot be distinguished from a normal connection.

Therefore, if a failure occurs in one communication line, there is a risk that a logical contradiction will occur within the system and the entire system will not operate properly.

This invention solves these problems,
The purpose is to detect incorrect connections of redundant communication lines at an early stage and prevent malfunctions from occurring.

(Means for Solving the Problems) The present invention to achieve such an object is such that a plurality of redundant communication stations are connected by redundant communication lines, and tokens are exchanged between the communication stations. In a redundant bus-type communication device that performs communication by circulating a bus, there is provided a token creation means for putting bus information used by the communication station on the token, a communication line actually used for communication by the communication station, and a communication line on the token. The present invention is characterized in that it is provided with a comparison means for comparing the information with the bus information, and an error transmission means for notifying an error when a discrepancy is detected by the comparison means.

(Operation) The token transmitting means adds information on the communication line used for token communication. The comparison means detects whether the communication line indicated by the token is connected to the corresponding bus. The error transmitting means notifies the erroneous connection of the communication line.

(Example) The present invention will be explained below using the drawings.

FIG. 1 is a block diagram showing an embodiment of the present invention. In FIG. 1, parts having the same functions as those in FIG. 4 are given the same reference numerals, and their explanations will be omitted. In the figure, TX1 is a transmitter connected to communication line BUS1, TX2 is a transmitter connected to communication line BUS2, RX1 is a receiver connected to communication line BUS1, and RX2 is a receiver connected to communication line BUS2. ,
BD1 is a bus detection device that operates when a token is received by either receiving unit RX1 or RX2, C1 is a control unit that controls the transmitter/receiver set TX1, RX1 and TX2, RX2, and SR1 is a control unit that controls the status of communication station S1. The stator register shown in the figure is readable from the outside and can be used to recognize whether it is in an error state or a normal state.

RX is the received signal extracted from reception RX1 and RX2 by bus detection device BD1, RBN is bus detection device BD1
TC1 is a token that adds to the token information which communication line BUS1 or 2 to use when the communication station S1 holds the token. It is a means of creation.

Note that the other communication stations S2 to S4 also have the same configuration as the communication station S1.

FIG. 2 is a diagram showing the structure of a token that gives control of a communication line between communication stations. In the figure, F is a flag indicating a break, DA is a delivery address,
SA is a source address, and CTL is a control signal, which contains information regarding the communication lines BUS1 and BUS2 added by the token creation means TC1. CRC is a communication error check signal using a generator polynomial.

A communication device that handles tokens configured in this manner operates as follows.

<Transmission of Token> When transmitting a token, bus information is added to the token by the token creation means TC1 and transmitted from the transmitter TX to the communication line BUS.

<Receiving a token> When receiving a token, the operation is as shown in the flowchart of FIG. 3. The token reaches the bus detection device BD1 from the communication line BUS via either receiver RX1 or RX2. The bus detection device BD1 sends the token as it is to the control unit C1, and also
Which receiver RX1 or RX2 received the signal is output to RBN. The control section C1 is inside the token.
Extract the bus information TBN regarding the communication line from the CTL (S1). Thereafter, the bus information TBN and RBN are compared (S2), and if they do not match, bus misconnection information is written to the stator register SR (S3). Thereafter, the process returns to the normal loop and performs normal token reception processing (S4). Note that if a match is detected, normal token reception processing is immediately performed.

(Effects of the invention) As explained above, according to the invention, incorrect connections in communication lines can be automatically checked online using the stator register SR, so incorrect connections in the system can be easily corrected. This has the practical effect of eliminating malfunctions due to misconnections of communication lines that occur during abnormalities, and improving the reliability of the entire system.

[Brief explanation of drawings]

Fig. 1 is a block diagram showing an embodiment of the present invention, Fig. 2 is a block diagram of a token, Fig. 3 is a flow chart showing the operation when receiving a token, and Fig. 4 is a block diagram of a conventional device. . TC...Token creation means, C...Control section (comparison means), SR...Stator register (error transmission means).

Claims (1)

[Claims for Utility Model Registration] A redundant bus-type communication device in which a plurality of redundant communication stations are connected by redundant communication lines, and a token is circulated among the communication stations to perform communication. A token creation means for putting bus information used by the communication station on the token; a comparison means for comparing a communication line actually used for communication by the communication station with the bus information on the token; and this comparison means. 1. A redundant bus type communication device, comprising: an error transmission means for notifying an error when a mismatch is detected.