JP3127941B2 - Redundant device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a duplexer having a computer system in a duplex configuration. More specifically, each computer system is connected to a communication line (network) via a communication control unit. The present invention relates to a duplexer in which a system carries out communication (data transmission) by using a communication line by carrying a communication right (token), and relates to a duplexer capable of correctly performing a diagnosis of a communication system.

[0002]

2. Description of the Related Art In a distributed control system requiring high reliability, a computer system in charge of a control operation and the like and a communication control unit for coupling these computer systems to a communication line have a dual configuration. A duplex configuration is adopted so that if one fails, the other can back up.

FIG. 3 is a conceptual diagram showing the structure of a conventional duplexer of this type. In the figure, FC1 and FC2 are computer systems having a redundant configuration, and correspond to, for example, distributed control stations. The BS is a communication line to which a plurality of other computer systems are connected. This communication line may also have a duplex configuration for the purpose of improving reliability. CA1 and CA2 are communication control units that connect each computer system to the communication line BS and perform communication control of the token path system (communication by circulating a communication right called a token between communication stations connected to the communication line). (A communication control method for performing control).

In such an apparatus, in order to maintain high reliability, failure detection by self-diagnosis becomes important. In such a self-diagnosis, for example, one computer system on the control side writes check data to the other computer system on the standby side at fixed intervals, and the other computer system writes the written check data at fixed intervals. A method of performing a failure diagnosis by reading and checking whether the read data matches the written data is adopted.

[0005]

When such a failure diagnosis method is performed, check data for the control computer system to write to the memory of the standby computer system using a communication line is determined by the control computer system using a token. However, if the communication load on the control-side computer system increases, check data cannot be transmitted in a predetermined cycle, and accurate diagnosis of the communication system in the duplex device cannot be performed. Failure occurs.

The present invention has been made in view of such a point, and the control side writes check data to the standby side on the standby side.
After confirming that the
Checking the check data
In computer systems, communication system
Even if the check data transmission interval becomes longer,
It is an object of the present invention to provide a duplexing device that can reliably diagnose a failure or an abnormality of a communication system .

[0007]

SUMMARY OF THE INVENTION In order to achieve the above object, according to the present invention, a computer system including a communication control unit connected to a communication line has a duplex configuration, and signals for duplex control which are mutually exclusive. Based on the above, one computer system is a duplexer in which the other computer system operates as a standby side and the other computer system operates as a standby side, and each of the computer systems checks a specific address of a memory of a partner computer system. Check data writing means for writing data via a communication line, a transmission counter updated each time check data is transmitted by the check data writing means, and transmission counter reference means for referring to the transmission counter in the partner computer system. When the transmission counter reference means detects an update of the contents of the transmission counter, Data check means for reading the check data written in the address and checking the pattern and update, and an alarm for outputting a signal for notifying a communication system error when an error is detected as a result of the check by the data check means and means, the check data writing means of the control side via a communication line, write a check data to a specific address of the memory of the standby side, the transmission counter reference means stand side,
Referring to the transmission counter on the control side, the data check means on the standby side reads out the check data written at a specific address of the memory on the standby side when the update of the transmission counter on the control side is detected, and This is a duplex device characterized by checking for updates of patterns and data.

[0008]

The check data writing means in the computer system on the control side transmits the check data via the communication line and writes the check data to a specific address of the memory in the standby computer system. The transmission counter in the controlling computer system is updated every time check data is transmitted.

The transmission counter reference means of the standby computer system refers to the transmission counter in the control computer system by, for example, backboard access and checks whether it has been updated. When an update of the transmission counter is detected, the data check means of the standby computer system reads the check data written at a specific address in its own memory and checks whether the pattern or data is updated. Then, the abnormality of the communication system is determined.

[0010]

Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 is a conceptual diagram showing the configuration of an embodiment of the present invention. In the figure, the BS is a communication line for performing data transmission in the token pass system. Here, a communication line having a duplex configuration is shown here, but a single communication line may be used. F
C1 and FC2 are computer systems of a duplex configuration connected to the communication line BS, and these are signals for redundant control which have an exclusive relationship with each other (this signal is transmitted via a backboard or the like, though not shown). One computer system operates as a control side, and the other computer system operates as a standby side.

OP is a computer system FC having a redundant configuration.
1, an operation monitoring device positioned as a host computer with respect to FC2, connected to the communication line BS,
It monitors the operation of each computer system and performs control operations and operations. Although not shown here, other computer systems are connected to the communication line BS, and between these computer systems, communication rights (tokens) are sequentially carried over by each computer system. Communication control of a token pass method for performing data transmission is performed.

In each of the redundantly configured computer systems FC1 and FC2, reference numeral 1 denotes a communication control unit, which has an interface function with the communication line BS, and transmits and receives data based on token path data transmission control. I do. Reference numeral 2 denotes a memory, for example, a RAM, and an area for writing check data for performing a failure diagnosis of the communication system of each computer system is prepared at the specific address CA.

Reference numeral 3 denotes check data writing means for writing check data to a specific address CA of the memory 1 in the other computer system via the communication line BS.
When the own computer system is on the control side, a write operation is performed toward the standby computer system. Here, the check data writing means 3 is realized by, for example, a direct memory access (DMA) function. The check data to be transmitted is, for example, $ 1111 → $ 2222.
Like ＄ FFFF, the same data is arranged every 4 bits, and such a check data pattern is updated every transmission.

Reference numeral 4 denotes a transmission counter. The check data is written by the check data writing means 3 to the other party (standby side).
It is updated each time it is transmitted to the computer system. Reference numeral 5 denotes a transmission counter reference unit, which refers to the transmission counter 4 in the counterpart (control side) computer system via the backboard BB when it is on the standby side (accesses and reads out via the backboard). Function). This transmission counter reference means 5 is provided in the standby computer system.
For example, it is started in a diagnosis processing program for checking a communication system.

Reference numeral 6 denotes a data check unit. The transmission counter reference unit 5 operates as a transmission counter 4 in the control computer system.
When the update of the content of the check is detected, the check data written to the specific address CA of the own memory 2 is read,
It is configured to check the pattern and update. 7 is an alarm generating means, and a data checking means 6
When an abnormality is detected as a result of the check, a signal indicating an abnormality in the communication system is output.

The operation of the apparatus having the above-mentioned structure will be described below. FIG. 2 is a flowchart illustrating an operation for a communication system diagnosis process performed by the control-side computer system and the standby-side computer system. In the control-side computer system (for example, FC1), the communication control unit 1 first creates a frame for transmission (step 11), and requests the check data writing unit 3 to transmit. In response to the transmission request, the check data writing means 3 loads the check data into a communication frame, and the communication control unit 1 and the communication line BS
Is written to a specific address of the memory 2 in the standby-side computer system FC2 (step 12).

Next, it is determined whether the transmission of the check data is successful (step 13). If the communication is successful, the pattern of the check data (transmission data) is updated in preparation for the next transmission (step 14). . Subsequently, the transmission counter 4 is updated (step 15). Thereafter, another check of the CPU memory and the like is performed (step 16), and the process returns to step 12 in response to a transmission request from the communication control unit 1.

In the standby computer system FC2, when the program for the communication system diagnosis processing is started, first, processing such as initialization is performed (step 21), and then the transmission counter of the control computer system FC1 is executed. 4 is read out by, for example, backboard access,
It is determined whether the content has been updated from the previous value (step 22). Here, when it is determined that the transmission counter 4 has not been updated (when the value matches the previous value), the following steps are bypassed.

If it is determined that the transmission counter 4 has been updated (if it does not match the previous value), the value read there is stored as the previous value (step 23). continue,
The data check means 6 reads the check data written at a specific address of its own memory 2 and compares it with the check data value held from the previous time (step 24).

If the read check data value does not match the previous value (if it has been updated), the read value is stored as the previous value (step 25). Subsequently, a pattern check is performed on the read check data (step 26). This step 26
Is a check of whether the same 4-bit data is arranged, whether those patterns have been updated from the previous value, and the like. If the same 4-bit data is arranged and they are updated from the previous value,
The communication system is determined to be normal. If any of them is incorrect, the communication system is determined to be abnormal. Here, factors that may determine that the communication system is abnormal include the reception processing and frame processing of the communication control unit of the standby computer system, the transmission processing of the communication control unit of the control computer system, and communication on the communication line. A defect is assumed.

The alarm generating means 7 receives the result of the check by the data checking means 6, and outputs a message or status signal indicating normal or abnormal, for example,
It is output by a backboard signal or the like and notified to the control-side computer system FC1. (Steps 27 and 29). After the notification of the check result, for example, it waits for one second (step 32) and returns to step 22.

The control computer system FC1 receives the notification indicating the check result of the communication system and transmits it to, for example, the higher-order operation monitoring device OP. Alternatively, it is output in the control-side computer system FC1. In this embodiment, a non-update counter is separately provided. Then, in step 24, if the check data read from its own memory 2 has not been updated (if it matches the previous value), the non-update counter is incremented (step 30), and the value of the non-update counter becomes It is determined whether the count value has reached a predetermined value (for example, four times) (step 31). If the non-update counter counts up, that is, even if a certain time has elapsed, the check data is not counted. If the update has not been performed, it is determined that the communication system is abnormal, and the process branches to step 27 to output a message indicating the abnormality.

After the check in step 26,
A step 28 is provided for setting the non-update counter to "0" after it is determined to be normal. As described above, the check data is transmitted from the control-side computer system by providing the non-update counter. However, in the standby-side computer system, the state that the writing to the specific address is not normally performed is performed several times ( After confirming the continuation, for example, four times, an abnormality determination is made to prevent the occurrence of an abnormal signal frequently.

In the above description, the transmission counter reference means 5
Has been described assuming that the transmission counter 4 in the control-side computer system is read via the backboard. However, the transmission counter 4 may be read without passing through the communication line BS, and is not limited to backboard access.

[0025]

As described in detail above, the present invention
Indicates that the control side writes check data to the standby side.
Was written by the controller after confirming that
Check data is configured to be checked
Therefore, in the control-side computer system, various loads (work loads) increase and the communication load increases, so that the transmission interval of check data for diagnosing an abnormality in the communication system becomes longer. In addition, it is possible to reliably diagnose a failure or abnormality of the communication system, and a highly reliable duplexer can be realized.

[Brief description of the drawings]

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

FIG. 2 is a flowchart illustrating an operation for a communication system diagnosis process performed by a control-side computer system and a standby-side computer system.

FIG. 3 is a configuration conceptual diagram of a conventional duplex device.

[Explanation of symbols]

 BS communication line FC1, FC2 Redundant computer system 1 Communication control unit 2 Memory 3 Check data writing unit 4 Transmission counter 5 Transmission counter reference unit 6 Data check unit 7 Alarm generation unit stage

Claims (1)

(57) [Claims] A computer system including a communication control unit coupled to a communication line has a duplex configuration, and one computer system is controlled on the control side and the other computer is based on a signal for redundant control which is mutually exclusive. Check data writing means for writing, via a communication line, check data to a specific address of a memory of a counterpart computer system in each of the computer systems, wherein the system is configured to operate as a standby side. A transmission counter that is updated each time check data is transmitted by the check data writing unit; a transmission counter reference unit that refers to the transmission counter in the partner computer system; and the transmission counter reference unit detects an update of the content of the transmission counter. Read the check data written to the specific address of the memory. A data checking means for checking the pattern and updated, if the data checking means checks the result of the abnormality is detected, including an alarm generating means for outputting a signal notifying the abnormality of the communication system, the control side The check data writing means writes the check data to a specific address of the memory on the standby side via the communication line, the transmission counter reference means on the standby side refers to the transmission counter on the control side, and the data check means on the standby side. Read out the check data written at a specific address of the memory on the standby side and check the update of the pattern and the data when the update of the transmission counter on the control side is detected. .