JPH0414895B2 - - Google Patents

Description

[Detailed Description of the Invention] [Field of Application of the Invention] The present invention relates to a communication control method that forms multiple communication paths in a loop between a plurality of computer systems, and particularly relates to a communication system when a failure occurs in a communication control unit. The present invention relates to a line control method for a multiple loop communication system suitable for improving reliability through continuous operation.

[Background of the invention]

In a conventional communication system that forms multiple communication paths in a loop between multiple computer systems, the line control function of the communication control unit of each computer system is to control multiple communication circuits, and when an abnormality in received data is detected. The line is being switched to the normal line. In addition, in the line control method of this conventional multiple loop communication system, when any of the following factors occurs: a power outage, a failure of the self-communication control unit, or a manual line disconnection command during maintenance, the communication line receives a signal. A line bypass is performed by disconnecting the line that inputs communication from each to its own communication control unit.
As for its configuration, the system shown in the communication control block diagram shown in FIG. 3 is generally used.

In the figure, 2A and 2B are dual system communication circuits, 3 is a communication control section of the computer system, and 4 is a communication control circuit section.

Each communication line output signal 11A, 11B from the communication control circuit section 4 is transmitted to each communication line communication circuit 5.
A, 5B, and the output signals 14A, 14B of the respective communication line transmitting circuit units 5A, 5B are connected to the respective line bypass relay contacts RA1-a, RB1-.
connected to a, each line bypass relay contact
Communication line 2A via RA1-c and RB1-c,
Sent to 2B.

In addition, input signals from each communication line 2A, 2B are sent to each line bypass relay contact RA2-c,
The input signals 15A, 15A, and 15A of the communication line receiving circuits 6A, 6B are connected to RB2-c, and are connected to the communication line receiving circuits 6A, 6B via the line bypass relay contacts RA2-a, RB2-a, respectively.
15B, and each communication line input signal 12 from each communication line receiving circuit unit 6A, 6B.
A and 12B are connected to the communication control circuit section 4. Moreover, each bypass relay drive signal 13A, 13B from the communication control circuit section 4 is connected to each input side of each bypass relay drive section 7A, 7B. When a disconnection command from each communication line 2A, 2B is detected during a power outage, when a failure occurs in the control unit of each communication line, or a manual line disconnection command during maintenance, the communication control circuit unit 4 disconnects each unit 7.
Relays A and 7B are de-energized. When the relay becomes de-energized, each line bypass relay of the output signal to each communication line 2A, 2B, contact RA1-
The one that was ON between c, RB1-c and RA1-a, RB1-a is the line bypass relay contact RA1-
c, RB1-c and RA1-b, RB1-b are ON
Then, input signals from each communication line 2A, 2B are transmitted to communication line 2 via each line bypass relay.
It is output to A and 2B.

The output signals 14A, 14B of each communication line sending circuit section 5A, 5B and the input signals 15A, 15B of each communication line receiving circuit section 6A, 6B are separated from each communication line 2A, 2B. In this method, when there is an abnormality in the entire communication control unit, that is, when all communication line control units 5A, 5B, 6A, and 6B are disconnected from the line (power outage or when the common part of each communication control unit circuit When a failure occurs or a manual line disconnection command is issued during maintenance, the communication line 2A,
Communication line data from the upstream system inputted from 2B is directly input to the communication line receiving circuit of the communication control unit in the downstream computer system via each line. Therefore, no matter which line is selected by the communication control unit in the downstream computer system to perform reception processing, the data is the same and no communication abnormality occurs. In addition, disconnection of the communication path on the route from any of the communication line control units 4 to the input to the communication line receiving circuit of the communication line control unit of the downstream computer system, poor contact of the bypass relay contact, or defective circuit, etc. If no received data or abnormal data is detected, the receiving circuit section switches to another normal line and performs reception, so no communication abnormality occurs. However, if a factor occurs that causes only one of the communication line control units to be disconnected from the line (failure of only the communication control unit of the own line), the communication line receiving circuit for communication control of the downstream computer system will not function properly. Normal data from the line side and bypassed data (abnormality) from the abnormal line side are input. However, in both cases, no formal abnormality (rationality check) is detected and line switching does not occur, so if the receiving circuit is selected as the abnormal circuit, normal data will be ignored and communication will be interrupted. There was a problem in that an abnormality occurred. Related systems of this type include, for example, Utility Model Application Publication No. 52-146799.
An example is a ring transmission device.

[Purpose of the invention]

The purpose of the present invention is to switch lines when a factor occurs that causes only one of the communication line control units to be disconnected from the line (failure of only the communication control unit of the own line) even if the line is normally normal. An object of the present invention is to provide a line control method for a multiple loop communication system that can operate reliably.

[Summary of the invention]

In designing a communication system that forms a loop-like double communication path between multiple computer systems, the present inventors realized that unless the drawbacks of the conventional technology are resolved, there would be problems in terms of system reliability. Check and
This problem was solved by using a bypass relay drive signal, an exclusive logic circuit, a line abnormality monitoring relay contact, and one contact of the bypass relay.

The present invention provides a communication system in which multiple communication paths are formed in a loop between a plurality of computer systems, and when a failure occurs in a communication control circuit unit controlling each communication line, an output signal is output corresponding to each line. By effectively using the bypass relay drive signal that disconnects the communication control unit from each communication line and bypasses the line, and the relay contact, only one of the communication circuit control units can be disconnected from the line even if the communication circuit is normal. This is to ensure that the line switching operation is performed when a factor that causes the line to become disconnected occurs.

[Embodiments of the invention] Examples of the present invention will be described below.

An embodiment of the present invention will be described with reference to FIGS. 1 and 2. Figure 1 is a diagram showing the overall configuration, and 1 ₁
A measurement control system is formed by ~1n computer systems. 2 between each of these computer systems.
This is a system in which communication lines A and 2B are connected in a double loop to communicate and perform measurement control. Here, the communication control unit 3 of each computer system 1 ₁ to 1n
The disconnection and recovery control from each communication line 2A and 2B is performed for each line in the event of a power outage, failure of each communication line control unit 3, manual line disconnection command during maintenance, etc. It is assumed that each communication line 2A, 2B is bypassed using a relay contact that becomes de-energized, and when the cause is removed, the relay can be energized and returned to each line 2A, 2B. . It also controls each communication line, selects each receiving circuit, and checks the presence or absence of data and rationality, and automatically switches when an abnormality is detected. It is also assumed that each sending circuit section is capable of sending out the same data. Under the above conditions, detailed circuit configurations and operations will be explained below using the block diagram of a communication control section within each computer system showing one embodiment of FIG. 2 and the block diagram of a conventional communication control section of FIG. 3. The communication control unit 3 of each computer system is configured as follows. The interface signal 10 with the computer is connected to the communication control circuit section 4 . Each communication line output signal 11A, 11B from the communication control circuit section 4 is connected to each communication line transmission circuit section 5A, 5B, and the output signal 14A, 1 of each communication line transmission circuit section 5A, 5B is connected to each communication line transmission circuit section 5A, 5B.
4B is each line bypass relay contact RA1-
a, RB1-a, and RA1 through each line bypass relay contact RA1-c, RB1-c.
-C side communication line sending line 16A is line bypass relay contact RB3-c and line abnormality monitoring relay contact
connected to RC1-c and connected to RB3-b and RC1- respectively
is sent to the communication line 2A via RB1-c.
The side communication line sending line 16B is a line bypass relay contact RA3-c and a line abnormality monitoring relay contact RC.
2-c and connected to RA3-b and RC2-b respectively
It is sent to the communication line 2B via. Input signals from the respective communication lines 2A and 2B are connected to the respective line bypass relay contacts RA2-c and RB2-c and sent to the respective communication line receiving circuit units 6A and 6B via R2A-a and R2B-a, respectively. input signal 15 of
The communication line input signals 12A, 12B from the respective communication line receiving circuit units 6A, 6B are connected to the communication control circuit unit 4. Further, each bypass relay drive signal 13A, 13B from the communication control circuit section 4 is connected to each input side of each bypass relay drive section 7A, 7B and exclusive OR circuit 8. The output signal of the exclusive OR 8 is connected as a line abnormality monitoring relay drive signal 18 to a line abnormality monitoring relay driving section. Each line bypass relay contact RA1-b, RB1-b
Similarly, each line bypass relay contact RA2-
b and RB2-b are each bypass communication line 1
Connected as 7A and 17B. Each line bypass relay contact RA1~RA3, RB1~
RB3 and line abnormality monitoring relay contacts C1 to RC2,
Each c indicates a common side of the contact, each a indicates a contact that turns on when the relay is energized, and each b indicates a contact that turns on when the relay is not energized. is the configuration of the communication control unit 3 of the computer system showing one embodiment of FIG.
The configuration of the conventional communication control section 3 shown in FIG. 3 includes an exclusive OR circuit 8 and a line abnormality monitoring relay drive section 9.
and each line bypass relay contact RA3, RB
This is a configuration that does not include 3. With the above-described circuit configuration, each computer system ₁₁ to 1n can operate its own communication control unit 3, and each communication circuit can be disconnected by a manual line disconnection command at the time of power outage, failure of the control unit of each communication line, or during maintenance. When a disconnection command from 2A, 2B is detected, communication control circuit section 4 issues respective bypass relay drive signals 13A, 13B to de-energize the relays of respective bypass relay drive sections 7A, 7B.
When the relay is de-energized, each communication line 2A, 2
Each line bypass relay contact for the output signal to B
RA1-c, RB1-c and RA1-a, RB1-a
between RA1-c, RB1-c and RA1-b,
RB1-b is turned on, and each communication line 2
Line bypass relay contacts RA2-c, RB2-c and RA2-a, RB for input signals from A, 2B
ON between 2-a is RA2-c, RB2-c and RA2-
b, RB2-b is turned on, and each line 2A,
The input signal from 2B is sent to each line bypass relay contact RA2-c, RB2-c←→RA2-b, RB
2-b and each bypass communication line 17A, 17
B and each line bypass relay contact RA1-
b, RB1-b←→RA1-c, RB1-c to the respective communication line sending circuits 16A, 16B, and the output signals 14A, 14B of the respective communication line sending circuits 5A, 5B, and each The input signals 15A, 15B of the communication line receiving circuit units 6A, 6B are separated from the respective communication lines 2A, 2B. Also, when both bypass relay drive signals 13A and 13B are shared by an exclusive OR circuit 8 which receives each bypass relay drive signal 13A and 13B as input, and
When both bypass relay drive signals 13A and 13B are absent, that is, only when both lines are normal and abnormal, the line abnormality monitoring relay is de-energized, and the respective communication line sending lines 16A and 16B are connected to the line abnormality monitoring relay contact. RC1-c, RC2-c and RC1-b,
It is led to each line 2A, 2B via RC2-b. Also, if either one is abnormal, the line abnormality monitoring relay is energized and both lines 2A and 2B relay contact RC1-
c, RC2-c and RC1-a, RC2-a cut off lines 2A and 2B. Each line bypass relay contact RA1, RA2, RB is connected in parallel with these line abnormality monitoring relay contacts RC1, RC2.
1. When an abnormality occurs in the own line that operates in synchronization with RB2 and the bypass occurs, the other lines are connected to each other, and the respective communication line sending lines 16A and 16B are connected to the respective lines 2A and 2B.
Relay contacts RC1-c, RC2-c←→RC1-b,
It is led via RC2-b. With the above functions, the abnormality monitoring relay contacts RC1 and RC can be installed with a simple circuit configuration.
2 and each line bypass relay contact RA3, RB
By the combination of 3, when both lines are normal, relay contacts RC1-c←→RC1-b and RC2-c←→RC2-
b and connects to each line 2A, 2B, and when both lines are abnormal, relay contacts RC1-c←→RC1-b and RB3-c←→RB3-b, RC2-c←→RC2-b
and RA3-c←→RA3-b to connect 2A and 2B to each line, and if only one is abnormal, relay contact RB3-c←→RB3-b or RA3
-c←→RA3-b connects only the normal line side to the line, disconnects the abnormal line side, creates a dataless state in the downstream computer system, and causes the communication control unit of the downstream computer system to detect an abnormality in received data. It is possible to realize a line control method for a multiple loop communication system that eliminates the drawbacks of the prior art by causing the switching to occur.

〔Effect of the invention〕

According to the present invention, with a simple circuit configuration, a failure can occur in a circuit that controls one of the communication lines, such as a communication control circuit that controls each communication line in a communication system that forms multiple communication paths in a loop. Even if a disconnection occurs from the communication line, if the other communication lines are normal, the abnormal line will be cut off and the downstream computer system will detect no data, and if this abnormal line is selected, the other It is possible to select the normal line side and continue communication operation, which is effective in improving the reliability of the entire system.

[Brief explanation of drawings]

FIG. 1 is an overall configuration diagram, FIG. 2 is a block diagram of a communication control section within the computer system of FIG. 1 showing one embodiment, and FIG. 3 is a block diagram of a conventional communication control section. 1 ₁ ~ 1n... calculation system, 2A, 2B...
Communication line, 3... Communication control unit of computer system,
4... Communication control circuit, 5A, 5B... Communication line transmitting circuit section, 6A, 6B... Communication line receiving circuit section,
7A, 7B... Bypass relay drive unit, 8... Exclusive OR circuit, 9... Line abnormality monitoring relay drive unit, 10... Interface signal with computer,
11A, 11B...Communication line output signal, 12A,
12B...Communication line input signal, 13A, 13B...
...Bypass relay drive signal, 14A, 14B...
Output signals of 5A, 5B, 15A, 15B...6
A, 6B input signals, 16A, 16B... Communication line sending line, 17A, 17B... Bypass communication line, 18... Line abnormality relay drive signal, RA1
~RA3...Line bypass relay contact, RB1~
RB3...Line bypass relay contact, RC1, RC
2... Line abnormality monitoring relay contact.

Claims (1)

[Claims] 1. In a multiple loop communication system in which multiple communication paths are formed in a loop between computer systems to perform communication, the communication control unit of each computer system is
Controls multiple communication circuits, switches lines when an abnormality is detected in received data, and drives bypass relays corresponding to each line when a power outage occurs, when a failure occurs in the self-communication control unit, or when a manual line disconnection command is issued during maintenance. A communication control circuit section that emits a signal, a bypass relay drive section that operates by a bypass relay drive signal corresponding to each line, and an input signal from each communication line and an output signal to each communication line are separated from the communication line. , a line bypass relay contact for bypassing, a line control relay contact that closes the other communication line when the own communication line is bypassed, and a bypass relay drive signal corresponding to each of the above communication lines as input to detect line abnormality. , an exclusive OR circuit that outputs an output to the line abnormality monitoring relay drive section only when one of the lines is in the bypass state, a line abnormality monitoring relay drive section that operates when the line is abnormal, and a circuit that shuts off the bypass state circuit when the line is abnormal. A line control method for a multiple loop communication system, characterized in that it is equipped with a line abnormality monitoring relay contact.