JPS63182934A - Supervisory system for multi-point communication system - Google Patents

Abstract

PURPOSE:To allow a master station to receive an error notice quickly by sending an error notice text repetitively if a slave station detects the error and stopping the transmission of a reply text in detecting the collision state of a text on a line so as to receive the error notice signal. CONSTITUTION:When an error detection section 18 detects an error, an error notice text 52 described with an error content is requested for transmission repetitively to a secondary channel transmission/reception section 16 and replies a prescribed reply signal 51 when the system is normal. In receiving the error notice text 62, the transmission of the reply request text 50 is stopped, and after the error notice identification text 63 is sent to the said slave station 11a, the polling is restarted. In detecting the collision of texts, the transmission of the reply request text 50 is stopped and the reception of the error notice text 52 is awaited. The error notice signal 52 is received quickly by detecting the collision state to stop the polling in this way.

Description

[Detailed Description of the Invention] [Required 4] In a monitoring system using a multipoint communication method, when a slave station detects an abnormality, it immediately sends an abnormality notification message to the master station, and when messages collide on the line, This is a monitoring method that cancels the collision state by stopping the sending of response messages, and then receives an abnormality notification message.

[Industrial application field]

The present invention relates to an improvement in a monitoring method in a multipoint communication system.

The monitoring system in the 7/L/Chipoint communication method is
The master station sends a response request message (polling) at predetermined intervals to make the slave stations respond and monitor them, but when an abnormality occurs in the slave station and notifies the master station, the master station polls the slave station. If you wait, there is a problem that the abnormality notification will be delayed.

This delay increases as the number of slave stations connected to the line increases, so a monitoring system that solves the above problem is required.

[Conventional technology]

FIG. 6 shows an example of a system configuration, and FIG. 7 shows an explanatory diagram of a conventional monitoring system.

FIG. 6 shows a monitoring system in which a master station 1 monitors slave stations 2 to 4. The slave stations 2 to 4 are multi-point connected via a line 100 and are configured to perform full-duplex communication with the master station 1. It is composed of

The master station 1 transmits a response request message 50 at predetermined intervals in order to monitor the slave stations 2 to 4, and when the slave stations 2 to 4 receive the response request message 50 for themselves, they send the response message 51 to the master station.
respond to

When an abnormality occurs in the slave stations 2 to 4, the abnormality notification message 5 is sent at the timing of its own response message 51, as shown in FIG.
2, and the master station 1 receives this and recognizes the abnormal state of the slave station.

In this way, the slave stations 2 to 4 wait until the response request message 50 for themselves and then notify the master station 1 of the abnormality.

[Problem that the invention seeks to solve]

As mentioned above (in the multi-point communication method, an error notification from a slave station to the master station is performed during self-polling, but if a large number of slave stations are connected, it takes time from the occurrence of an error to the notification. There is a problem.

SUMMARY OF THE INVENTION In view of the above-mentioned problems, it is an object of the present invention to provide a monitoring system for a multipoint communication system that allows a master station to quickly receive an abnormality notification message.

[Means for solving problems]

For the above purpose, the monitoring method in the multipoint communication system of the present invention repeatedly sends an abnormality notification message (52) to the master station from the time an abnormality is detected, as shown in Figure 1, a diagram explaining the principle of the present invention. The abnormality notification message sending unit (19) is connected to the slave station (
11), a collision detection unit (15) that detects a collision state of messages on the line (100), and a stop control means (15) that stops sending the response message (51) when the collision state of messages is detected. 20) is provided in at least one of the master station (10) and the slave station (11).

[Effect]

When an abnormality occurs, the slave station repeatedly transmits an abnormality notification message 52 to the master station 10.

This abnormality notification telegram 52 is immediately received by the master station 10, but if it collides with another telegram on the concave line 100, the master station 10 cannot receive it, so the collision state is detected and canceled.

In the full-duplex communication system, this is a collision with the response message 51 of another slave station, and in order to resolve this, (1) a collision detection section 15 is provided in the master station 10, and when a collision state is detected, an abnormal state occurs. It recognizes this and stops sending the response request message 50.

(2) A collision detection section 15 is provided in the slave station 11, and the transmission of the response message 51 is stopped when a collision is detected.

(3) Use the measures in (1) and (2) above together.

There is a method.

Note that in the half-duplex communication method, the above (1) and (3) of stopping the sending of the response request message 50 are adopted.

As a result of the above, the master station 10 receives the abnormality notification message 52 from the slave station 11.
can be received promptly.

〔Example〕

Embodiments of the present invention will be described with reference to FIGS. 2 to 5.

Fig. 2 is a block diagram of main parts of a modem in an embodiment of the modem monitoring system, Fig. 3 is a time chart of an example of operation, Fig. 4 is an operation flowchart of a slave station that detects an abnormality, and Fig. 5 is a block diagram of a main station of a master station. It is an operation flowchart figure.

This embodiment takes as an example a modem monitoring system in a system in which a host computer and a terminal are connected via a modem at multiple points, and shows a system in which a collision detection section 15 is provided in a master station 10.

Slave station 11 in Fig. 2 (each slave station is ila~ll)
c), 16 is a secondary channel transmitting/receiving unit that performs full-duplex communication for monitoring with the master station 10, and forms a channel different from that for data transfer to transmit and receive messages for monitoring. .

Reference numeral 18 denotes an abnormality detection unit, which monitors the communication state of the slave station 11 and detects an abnormal state.

17 is a response unit which, when the abnormality detecting unit 18 detects an abnormality, repeatedly requests the secondary channel transmitting/receiving unit 16 to send an abnormality notification message 52 containing the abnormality details, and when the abnormality is normal, sends a predetermined response signal. 51 as a response, and corresponds to the abnormality notification message sending unit 19 in FIG.

Further, in the master station 10, 13 is a secondary channel transmitting/receiving unit, which corresponds to the secondary channel transmitting/receiving unit 16 of the slave station, and 14 is a response request message transmitting unit, which sequentially sends response request messages 50 to each slave station at predetermined intervals. , and stops the above-mentioned transmission upon notification from the collision detection section 15, which corresponds to the stop control means 2°0 in FIG.

15 is a collision detection unit, which is connected to the receiving line 100a of the line 100;
is monitored to detect a collision of messages and notify the response request sending unit 14.

Reference numeral 12 denotes a reception processing unit which analyzes the received response message 51 and abnormality notification message 52, and when confirming the reception of the abnormality notification message 52, sends the failure notification recognition message 53 to the slave station where the failure has occurred (referred to as 11a). ), and then starts sending the response request message 50.

In the modem monitoring system having the above configuration, the operation when an abnormality occurs will be explained with reference to FIGS. 3 to 5.

(1) When the master station 10 does not receive the abnormality notification message 52 and does not detect a collision of messages, it repeats polling of the slave station 11 at a predetermined period.

(2) When receiving the abnormality notification message 52, it stops sending the response request message 50, sends the abnormality notification recognition message 53 to the nuclear station 11a, and then resumes polling.

(3) When a collision of messages is detected, the sending of the response request message 50 is stopped and the reception of the abnormality notification message 52 is waited.

(4) When receiving the abnormality notification message 50, perform processing according to (2) above.

Note that the collision state may be detected by, for example, a parity check of a message.

By detecting a collision state and stopping polling as described above, the abnormality notification signal 52 can be promptly received.

The above is a method in which the master station 10 detects a collision state, recognizes an abnormal state, and takes action. However, as described above, the slave station is provided with a collision detection section, and when a collision state is detected, the response message 51 is sent. The same effect can be obtained by stopping the collision detection section, and a collision detection section may be provided in both the master station and the slave station.

〔Effect of the invention〕

The present invention provides a multipoint communication system in which when a slave station detects an abnormality, it repeatedly sends out an abnormality notification message, and when it detects a collision state of messages on the line, it stops sending response messages and receives an abnormality notification signal. Since the present invention provides a monitoring method in the above, the effect that the master station can quickly receive an abnormality notification is extremely large.

[Brief explanation of the drawing]

Fig. 1 is an explanatory diagram of the principle of the present invention, Fig. 2 is a block diagram of main parts of a modem according to an embodiment, Fig. 3 is a time chart of an operation example, and Fig. 4 is an operation flowchart of a slave station that detects an abnormality. 5 is an operation flowchart of the master station, FIG. 6 is a diagram showing an example of a system configuration, and FIG. 7 is an explanatory diagram of a conventional monitoring system. In the figure, 1 is a master station, 2 to 4 are slave stations, 10 is a master station, LL, LLa to Ilc are slave stations, 12 is a reception processing unit, 17 is a response unit, 18 is an abnormality detection unit, and 19 is an abnormality notification Message sending unit, 20 is a stop control means, 50 is a response request message, 51 is a response message, 52 is an abnormality notification message, 53 is an abnormality notification acknowledgment message, 100 is a line, and 100a is a receiving line.

Claims (1)

[Claims] A master station (10) sequentially sends a response request message (50) to a plurality of slave stations (11) connected via a line (100),
The slave station (11) responds by sending a response message (51), and the slave station where the error occurred sends an error notification message (52).
An abnormality notification message sending unit (19) that repeatedly sends the abnormality notification message (52) to the master station from the time when an abnormality is detected. is provided in the slave station (11), a collision detection unit (15) detects a collision state of messages on the line (100), and sends the response message (51) when the collision state of messages is detected. A stop control means (20) is provided in at least one of the master station (10) and the slave station (11) to stop the response message (51) when a collision of messages is detected on the line. A monitoring system in a multi-point communication system, characterized in that the transmission of the abnormality notification message (52) is stopped, the collision state is canceled, and the abnormality notification message (52) is received.