JP2010200063A - Transmission line fault detecting method and program - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a transmission line fault detecting method for detecting a fault on a transmission line even during the stop of data transmission. <P>SOLUTION: A communication device 2 transmits a fault detecting signal to a computer 1 at predetermined time intervals (t). The computer 1 monitors a log file at time intervals T greater than the transmission intervals (t) of the fault detecting signal, and when there is no reception record of the fault detecting signal received after last log file monitoring in the log file, the fault on the transmission line is determined. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a method for periodically detecting a failure in a transmission path between communication devices, and a program for causing a computer to execute this method.

  When a communication device, a measurement device, or the like is controlled by a computer, the connection between the two is generally performed using an RS-232C standard cable. In that case, a failure in the transmission path is detected based on the presence or absence of a response to polling (see Patent Document 1).

JP-A-8-56247 (see paragraph [0007])

  However, since polling is performed prior to the start of data transmission, it becomes impossible to detect a failure in the transmission line during the pause period of data transmission.

  In view of such circumstances, it is an object of the present invention to provide a transmission path failure detection method capable of detecting a transmission path failure even during a data transmission suspension period.

  To achieve the above object, the present invention provides a method for detecting a failure in a transmission path between communication devices, wherein one communication device transmits a failure detection signal to another communication device at a predetermined time interval. And when the other communication device monitors the log file at a time interval longer than the transmission interval of the failure detection signal, and when there is a reception record of the failure detection signal after the previous log file monitoring, While determining that the communication device is normal on the transmission path, if there is no reception record of the failure detection signal after the previous log file monitoring, from the step of determining that the other communication device is a transmission path failure It is characterized by becoming.

  In order to achieve the above object, the present invention is a program for causing a computer to execute a failure determination of a transmission path connected to a communication device, wherein the communication device sends a failure detection signal to the computer at a predetermined time interval. The computer monitors the log file at a time interval longer than the transmission interval of the failure detection signal, and if there is a reception record of the failure detection signal after the previous log file monitoring, the computer The computer determines that the transmission path is faulty when there is no reception record of the failure detection signal after the previous log file monitoring. And

According to the present invention, since one communication device transmits a failure detection signal to another communication device at a predetermined time interval regardless of the presence or absence of transmission data, a transmission line can be transmitted even during a data transmission suspension period. It becomes possible to detect the failure of the.
In addition, since other communication devices determine the failure of the transmission path based on the reception record of the failure detection signal in the log file, the received signal distribution process required when determining failure based on whether or not the failure detection signal is received Is easy to control.

It is a system configuration figure of a 1st embodiment used for implementation of the present invention. FIG. 2 is a block diagram of the system of FIG. 1. It is a time chart which shows the reception interval of a failure detection signal, and the monitoring interval of a log file. It is a figure which shows the content of the log file. It is a figure which shows 2nd Embodiment corresponding to FIG. It is a figure which shows 2nd Embodiment corresponding to FIG.

(First embodiment)
Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.
As shown in FIG. 1, a computer 1 and a communication device (controlled device) 2 are connected by a cable 3 of RS-232C which is an asynchronous serial transmission path. Data relating to the operation and state is sent from the communication device 2 to the computer 1. A command for controlling the operation is sent from the computer 1 to the communication device 2.

  As shown in FIG. 2, the computer 1 includes a transmission / reception unit 10 that exchanges data with the communication device 2, a data processing unit 11 that executes processing of data passed to the transmission / reception unit 10, and a transmission / reception unit 10. A storage unit 12 that stores transmission / reception records as a log file, a log file monitoring unit 13 that periodically monitors the log files in the storage unit 12, and a failure in a transmission path is determined by receiving and recording a failure detection signal in the log file. The apparatus includes a failure determination unit 14 and a notification unit 15 that notifies a transmission path failure by screen display or voice. The storage unit 12 includes a nonvolatile storage medium such as a hard disk or a flash memory.

  The communication device 2 includes a transmission / reception unit 20 that exchanges data with the computer 1, a data processing unit 21 that executes processing of data passed to the transmission / reception unit 20, and generates a failure detection signal to the transmission / reception unit 20. And a failure detection signal generation unit 22 to be sent. The failure detection signal includes a character string with which the computer 1 can identify the signal.

FIG. 3 is a time chart showing the relationship between the occurrence interval of the failure detection signal and the monitoring interval of the log file.
The failure detection signal is transmitted from the communication device 2 at a constant time interval t, and the reception record is recorded in the computer 1 as a log file. The log file monitoring unit 13 monitors the log file at an interval T longer than the generation interval t of the failure detection signal. When the failure detection signal is normally received, the reception records are sequentially left in the log file as shown in FIG. When the failure detection signal is not received due to a failure in the transmission path, the reception record of the failure detection signal of the log file is lost. Thereafter, it is checked whether or not there is a reception record of the failure detection signal received.

FIG. 4 shows an example of the log file.
In the log file, a failure detection signal reception record 100 and a normal data transmission / reception record 200 are described. The failure detection signal reception record 100 includes a reception time display 100a and a display 100b indicating the failure detection signal. Here, the generation interval t of the failure detection signal is set to 10 minutes. In this case, the log file monitoring interval T is set to 30 minutes.

  In the transmission / reception unit 20 of the communication device 2, FIFO (First In First Out) control is performed at the time of competition between the normal signal and the failure detection signal, so that the failure detection signal may be delayed. For this reason, the log file monitoring interval T needs to be made somewhat larger than the failure detection signal generation interval t. Further, when the reception time of the failure detection signal approaches or coincides with the monitoring time of the log file, the reception record cannot be detected, so the monitoring interval T of the log file is set to be twice or more the failure detection signal generation interval t. Thus, it is preferable that the reception times of at least two failure detection signals fall within the log file monitoring interval T. Note that the value of the log file monitoring interval T may be determined in consideration of system operation requirements.

  In the above method, since the communication device 2 transmits the failure detection signal at a predetermined time interval, it is possible to detect a failure in the transmission path even during the data transmission suspension period of the computer 1 or the communication device 2.

  By the way, the computer 1 can also determine the failure of the transmission path when it becomes impossible to receive the failure detection signal. In this case, the received signal output from the transmission / reception unit 10 is converted into a normal signal and a failure detection signal. Therefore, the control process becomes complicated.

(Second Embodiment)
FIG. 5 shows a system configuration diagram of the present embodiment.
The computer 1 is connected to a plurality of communication devices 2 via a console terminal device 30. The console terminator 30 functions as an interface that converts the data format exchanged between the computer 1 and the communication device 2, and also functions as a router that distributes data from the computer 1 to each communication device 2. The computer 1 and the console terminal device 30 are connected by a LAN cable 31. Each communication device 2 and the console terminal device 30 are connected by an RS-232C cable 32. The configurations of the computer 1 and the communication device 2 are the same as those in FIG.

FIG. 6 is a time chart showing the relationship between the occurrence interval of the failure detection signal and the monitoring interval of the log file.
Also in this embodiment, each communication device 2 transmits a failure detection signal at a fixed time interval t, and the computer 1 monitors the log file at an interval T larger than the failure detection signal generation interval t, and the previous monitoring. The failure of the transmission path is determined based on the presence or absence of the reception record of the failure detection signal received after that time. Although the failure detection signal is not synchronized between the communication devices 2, the failure detection signal is sent to the computer 1 via the console terminal device 30, so the reception time of the failure detection signal from each communication device 2 Causes a delay of at least the packet transmission time, and falls within the log file monitoring interval T. The log file monitoring interval T is preferably at least twice the failure detection signal generation interval t for the reasons described above.

  When the failure detection signal from each communication device 2 is normally received, the reception records are sequentially left in the log file as shown in FIG. When a failure detection signal is not received due to a failure in the transmission path, the reception record of the corresponding failure detection signal disappears from the log file, so that the failure detection means 14 causes the log file monitoring unit 13 to monitor the log file each time the log file is monitored. It is checked whether or not there is a record of the failure detection signal received after the monitoring, and if there is no record, the notification means 15 is activated. At that time, the failure of the transmission line connected to the communication device 2 that issues a failure detection signal with no reception record is notified.

  By the way, since the communication between the computer 1 and the console terminal device 30 is performed by TCP / IP, the failure detection of the LAN cable 31 can be easily performed by the software of the computer 1, but the communication between the console terminal device 30 and the communication device 2 is performed. It is difficult to detect the failure of the RS-232C cable 32 with the software of the computer 1 because it is performed using a physical layer protocol below the TCP / IP. Therefore, according to the method of the present embodiment, it is easy to detect a failure in each of the tables 31 and 32 configuring the network. Other effects are the same as those of the first embodiment.

  In the above embodiment, the failure detection of the cable connecting the computer 1 and the communication device 2 has been described. However, the type connected to the cable is not limited as long as it is a communication device. Also, the transmission path may be either wired or wireless.

1 Computer 2 Communication equipment (controlled equipment)
3 RS-232C cable 10 Transmission / reception unit 11 Data processing unit 12 Storage unit 12
13 Log File Monitoring Unit 14 Failure Determination Unit 15 Notification Unit 20 Transmission / Reception Unit 21 Data Processing Unit 21
22 Fault detection signal generator

Claims (7)

In a method for detecting a failure in a transmission path between communication devices,
One communication device transmits a failure detection signal to another communication device at a predetermined time interval; and
Monitoring the log file at a time interval longer than the transmission interval of the failure detection signal by the other communication device;
If there is a failure detection signal reception record after the previous log file monitoring, the other communication device determines that the transmission path is normal, but there is no failure detection signal reception record after the previous log file monitoring. In the case, the step of determining that the other communication device has a transmission path failure;
A transmission line fault detection method comprising:   2. The transmission line failure detection method according to claim 1, wherein a monitoring interval of the log file is at least twice as long as a transmission interval of the failure detection signal.   3. The transmission line failure detection method according to claim 1, wherein the other communication device is a computer, and the controlled device controlled by the computer is the one communication device.   3. The transmission path failure detection method according to claim 2, wherein the transmission path communication is performed by a physical layer protocol.   The transmission line failure detection method according to claim 1, wherein the computer is connected to a plurality of controlled devices via a console termination device.   The transmission path communication between the computer and the console termination device is performed by a network layer protocol, while the transmission path communication between the console termination device and the controlled device is performed by a physical layer protocol. The transmission path failure detection method according to claim 5. A program to be executed by a computer to determine a failure of a transmission line connected to a communication device,
When the communication device transmits a failure detection signal to the computer at a predetermined time interval, the computer monitors the log file at a time interval longer than the transmission interval of the failure detection signal;
If there is a failure detection signal reception record since the previous log file monitoring, the computer determines that the transmission path is normal, but there is no failure detection signal reception record since the previous log file monitoring Determining that the computer has a transmission line failure;
A program characterized by having executed.

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