JPH01158844A - Self-diagnostic system for multiplex loop communication system - Google Patents

Abstract

PURPOSE:To apply preventive maintenance by means of a fault diagnosis of a standby line side by providing a standby line selection circuit section selecting a standby line input signal and a retriggerable one-shot circuit section applying fault diagnosis of the standby line input signal and outputting a standby line fault detection signal. CONSTITUTION:A standby line selection circuit section 9 selected by a reception line selection signal 13 from a communication control circuit section 5 is arranged to multiplex communication line reception circuit sections 6A, 6B of a communication controller 2. Furthermore, the retriggerable one-shot circuit section 10 receiving a standby line input signal being the output signal, applying self-diagnosis due to any change and outputting a standby line fault detection signal to the communication control circuit section 5 is arranged. Thus, a standby line is selected and there is no change in the input signal occurred for a prescribed time or over, then it is discriminated that a fault or a failure such as an open line takes lace in an upperstream communication controller at the standby line side, or a communication line or its own communication line reception circuit section and the standby line fault detection signal is given to the communication control circuit section. Thus, it can be reported to a master computer from the communication control circuit section to attain preventive maintenance.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a self-diagnosis method for a communication system formed by loop-shaped multiple communication paths between a plurality of computer systems, and is particularly applicable to maintenance of a communication control device. Or a self-diagnosis method suitable for investigation when a failure occurs [Prior art] Line control of the communication control device of each computer system in a conventional communication system formed by multiple communication paths in a loop between a plurality of computer systems. The method is to select and input one of the input signals from multiple communication channels,
Generally, the same signal is sent out to multiple communication paths, and the communication control circuit section detects the presence or absence of the receiving line input signal, rationality check abnormality, etc. A common method is to continue communication operation by selecting and inputting input signals from other communication channels using a line selection signal, and the configuration is as shown in the block diagram of a conventional communication control device in Fig. 4. Ta.

However, this method does not take into account failure diagnosis on the standby line side of multiplex communication lines, so even if an abnormality is detected on the receiving line side and the receiving line is selected as the standby line side, communication operations will continue normally. There is no guarantee. In addition, even if the communication operation is performed normally, the abnormal line becomes a standby line and ostensibly normal communication operation continues, making it difficult to understand the abnormal line status at the time of maintenance inspection of the communication control device. Another problem is that it takes a long time to investigate when a communication abnormality occurs. In addition, related to this type of line control system, for example, the Utility Model No. 52-14
6799 circular transmission device.

[Problem that the invention seeks to solve]

The above conventional technology does not take into consideration failure diagnosis on the standby line side of multiple communication lines, so even if an abnormality is detected on the receiving line side and the receiving line is selected as the standby line side, communication operations may not be performed normally. There is no guarantee that it will be possible. In addition, even if communication operations are performed normally, the abnormal line becomes a standby line and ostensibly normal communication operations continue, making it difficult to understand the abnormal line status at the time of maintenance and inspection of the communication control device. This posed problems in terms of maintainability and reliability, as it took a long time to investigate the occurrence of errors or communication malfunctions. SUMMARY OF THE INVENTION An object of the present invention is to provide a self-diagnosis method for a multiple loop communication system that eliminates the drawbacks of the prior art.

[Means for solving problems]

The above purpose is to input a standby line selection circuit section selected by a reception line selection signal from the communication control circuit section and a standby line input signal of this output signal into a multiplex communication line reception circuit section of a communication control device. This is achieved by arranging a retriggerable one-shock 1 circuit section that performs self-diagnosis according to the method, outputs a standby line failure detection signal, and inputs it to the communication control circuit section.

[Effect]

According to the above means, the standby line input signal outputted by the standby line selection circuit unit configured to select a standby line other than the reception line selected by the reception line selection signal from the communication control circuit unit is ～Lee) The f-j le one-shot circuit is input, and a self-diagnosis is performed to check whether the input signal on the standby line is correct and there is a predetermined change, and if the input signal does not change for a certain period of time, the standby line side If an abnormality such as a failure or disconnection occurs in the upstream communication control device, the communication line, or the own communication line receiving circuit, the standby line failure detection signal shown in the time schedule in Figure 3 is input to the communication control circuit. , the communication control circuit can report to the main computer, allowing preventive maintenance.

〔Example〕

An embodiment of the present invention is shown in FIGS. 1, 2, and 3.

This will be explained with reference to FIG. FIG. 1 is an overall configuration diagram showing each computer system consisting of main computers 11 to 1n, communication control devices 21 to 2n connected by computer interface signals 31 to 3n, and these computer systems. This is a system in which computer systems are connected in a loop through dual 4A and 4B communication lines to communicate and perform measurement control. The communication control devices 21 to 2n here are
It controls data transfer with the main computers 11-1n and the communication lines 4A, 4.8, selects each receiving circuit section, checks the rationality of data reception 2, and automatically switches when an abnormality is detected. It is also assumed that each transmitting circuit section is capable of transmitting the same data.

Under the above conditions, Fig. 2 is a block diagram of a communication control device for a computer system showing one embodiment, Fig. 3 is a time schedule diagram showing the operation of the communication control device, and Fig. 4 is a block diagram of a conventional communication control device. The detailed circuit configuration and operation will be explained using .

The communication control device 2 of the computer system shown in FIG. 2 is configured as follows. The interface signal 3 with the computer is connected to the communication control circuit section 5 . Further, the input signals from the respective communication lines 4A and 4B are input to the respective communication line receiving circuit sections 6A and 6B, and the communication line input signal 11A, which is the output signal of the one communication line receiving circuit section 6A, is input to the respective communication line receiving circuit sections 6A and 6B. The communication line input signal 11B is connected to the input of the selection circuit section 7 and the B input section of the standby line selection circuit section 9, and is an output signal of the other communication line reception circuit section 6B.
It is connected to the B input section of the reception line selection circuit section 7 and the A input section of the standby line selection circuit 9.

The reception line input signal 12 from the reception line selection circuit section 7 is input to the communication control circuit section 5, and the reception line selection signal 13 from the communication control circuit section 5 is input to the reception line selection circuit section 7 and the standby line selection circuit section 9. is connected to the SEL input section of each of the. Also, the standby line input signal 1 from the standby line selection circuit section 9
5 is input to the retriggerable one-shot circuit section 10, and the standby line failure detection signal 16 of this output signal is input to the communication control circuit section 5. On the other hand, the communication line output signal 14 from the communication control circuit unit 5 is transmitted to each communication line transmitting circuit unit 8.
A and 8B, and these output parts are connected to each communication line 4.
Connected to A and 4B. Receiving line selection circuit section 7 here
And the standby line selection circuit unit 9 selects either the communication line input signal 11A or IIB of the A or B input unit according to the reception line selection signal 13 of the SEL input unit, and selects either the reception line input signal 12 or the standby line input. Assume that signal 15 is output. Also, the retriggerable one-shot circuit section 1o
As shown in the time schedule diagram of FIG. 4, here, the timer starts when the standby line input signal 15 rises, and if the rising signal is input again within the set time T, the timer restarts, and the timer restarts within the set time T. It is assumed that a time-up occurs if a rising signal is not input. The above is the configuration of the communication control device 2 of the computer system showing one embodiment of FIG. 2. In the configuration of the conventional communication control device 3 of FIG. 10. With the circuit configuration as described above, input signals from the respective communication lines 4A and 4B are subjected to waveform shaping, level conversion, etc. in the respective communication line receiving circuits 6A and 6B. These output communication line input signals 11A and IIB are connected so as to be selected and output as a reception line input signal 12 and a standby line input signal 15 by a reception line selection signal 13 from the communication control circuit section 5, respectively; The received signal is input to the reception line selection circuit section 7 and the standby line selection circuit section 9, and the respective output signals are sent out. This reception line input signal 12 is input to the communication control circuit section 5 and predetermined reception control is performed, while the standby line input signal 1
5 is input to the retriggerable one-shot circuit section, which performs a self-diagnosis to see if the standby line input signal is correct and has a predetermined change.If the input signal does not change for a certain period of time, the upstream side of the standby line Communication control device 2n, communication line 4A, 4.8, self communication line receiving circuit unit 6A,
A standby line failure detection signal 16 is input to the communication control circuit section 5 on the assumption that an abnormality such as a failure or disconnection has occurred in the 6B. Upon receiving this signal, the communication control circuit section 5 connects the main computer 1 to the main computer 1 via interface signals 31 to 3n with the computer.
1 to 1n can report standby line abnormalities. Fig. 3 shows a time schedule diagram showing the failure detection operation of the standby line, and shows failures when the standby line input signal 15 changes correctly and in a prescribed manner, and when there is no change from the + side to the one side at a certain point. A and each standby line failure detection signal at the time of failure 8 when there is no change from one side to the + side at a certain point in time, and only in the case of failure A and failure B, the retriggerable one-shot circuit section 10 Time up and report abnormality.

The line input signal here uses an unmodulated basepan 1 system, and when the data is 170 II, it goes from LOW to HIGH at the center of the bit, and when the data is "1", it goes HIGH at the center of the bit. This is expressed using a code format in which a level change occurs from LOW to LOW. LOW to HI in this code format
The sign change interval from a rising change to GH to a rising change occurs from t1 to t3, and t3 is the longest, and since a rising change occurs within 13 at least under normal conditions, the setting of the retriggerable one-shot circuit section is necessary. If time T>T3 is set, abnormality can be detected. Also, when an abnormality is detected on the receiving line side and the receiving line is selected as the standby line, the abnormal line becomes the standby line and the above-described failure diagnosis is performed. The communication line output signal 14 from the communication control circuit section 5 is level-converted by the communication line transmission circuit section for each communication line 4A, 4B, and the same signal is sent to each communication line 4A.

Sent to 4B. With the above functions, failure diagnosis on the standby line side can be performed with a simple circuit configuration, and a self-diagnosis method for a multiple loop communication system that eliminates the drawbacks of the conventional technology can be realized.

〔Effect of the invention〕

According to the present invention, with a simple circuit configuration, preventive maintenance is performed by fault diagnosis of the upstream communication control device on the standby line side, the communication line, and the self-communication line receiving circuit of a communication system formed from multiple loop-shaped communication paths. In addition, even if an abnormality is detected in the receiving line and the receiving line is selected as the receiving line, the abnormal line becomes a standby line and the above-mentioned fault diagnosis is performed, and the abnormal line status at the time of maintenance inspection is confirmed by the communication control circuit. Since the information is reported to the main computer through , it is effective in improving the maintainability and reliability of the entire system.

[Brief explanation of the drawing]

Fig. 1 is an overall configuration diagram, Fig. 2 is a block diagram of the communication control device of the computer system of Fig. 1 showing one embodiment, Fig. 3 is a time schedule diagram showing the operation of Fig. 2, and Fig. 4 is a conventional FIG. 2 is a block diagram of a communication control device of FIG.

Claims (1)

[Claims] 1. In a communication system formed by loop-shaped multiple communication paths between computer systems, the communication control device of each computer system detects abnormalities in data transfer with the main computer, receiving line side to the main computer, and standby line side. a communication control circuit unit that performs reporting, receiving side switching control of multiplex communication lines, transmission/reception control with other computer systems, etc.; a communication line receiving circuit unit that receives input signals from each communication line;
A reception line selection circuit section and a standby line selection circuit section select a communication line input signal between a reception line input signal and a standby line input signal based on a reception line selection signal, and perform abnormality diagnosis of the standby line input signal and generate a standby line failure detection signal. A multiplex loop characterized by comprising a triggerable one-shot circuit section that outputs and inputs it to a communication control circuit section, and a communication line transmission circuit section that transmits a communication line output signal from the communication control circuit section to each communication line. Self-diagnosis method for communication systems.