JPS62281545A - System for detecting fault in communication line - Google Patents

Abstract

PURPOSE:To detect a fault of a communication line even at a slave device by supervising whether or not a polling signal is reached within a predetermined period via a duplexed communication line. CONSTITUTION:When polling signal analysis sections 22,25 detect a polling signal P from a master equipment 1 via an outgoing communication line 31 or 41 in the slave equipment 2, the reception of the polling signal P is informed to a corresponding fault detection section 27 or 28. The fault detection sections 27, 28 do not receive the reception notice of the polling signal P from the master equipment 1 even once in the interval of the timing signal sent from the timing section 29, it is decided that a fault is generated in a corresponding communication line 3 or 4 to display the occurrence of the fault.

Description

[Detailed Description of the Invention] 3. Detailed Description of the Invention [Summary] In a communication system in which a main device and a slave device are connected through a duplex communication path and communication is performed in a polling format, By monitoring the polling signal transmitted from the main device to the slave device within a predetermined period, the slave device can also detect a failure occurring in the communication path.

[Industrial application field]

The present invention relates to an improvement in a communication path failure detection method in a polling type communication system in which a main device and a slave device are connected by a duplex communication path.

For example, in a centralized maintenance system that centrally monitors the operational status of multiple automatic exchanges, a central maintenance center periodically monitors the operational status of each automatic exchange via communication channels established between each automatic exchange. A so-called polling-type communication is performed in which a matching signal (hereinafter referred to as a polling signal) is transmitted, and each automatic exchange that receives the polling signal returns information indicating the desired operational status.

The communication channels connecting the central maintenance center and each automatic exchange are as follows:
Although duplication is considered in order to maintain high reliability, it is important that not only the central maintenance center but also the automatic switchboard be able to recognize that a failure has occurred in the communication channel. This is required to improve the reliability of the communication channel.

[Conventional technology]

FIG. 3 is a diagram showing an example of a conventional communication system.

In Fig. 3, the main equipment (M
ST) 1 and a slave device (SLV) 2 such as an automatic switchboard,
They are connected by duplex communication paths 3 and 4.

Although it is not uncommon for a plurality of slave devices 2 to be connected to the main device 1, only the -m slave device 2 is shown in FIG. 3 for simplification.

Inside the main device l, a boring signal generation unit (
PC) 11 and a response signal analysis unit (A
D) 12, a switching unit (SW) 13 that switches and connects the boring signal generation unit 11 and response signal analysis unit 12 to either of communication paths 3 and 4, and Transmitting/receiving units (SR) 14 and 17 for transmitting and receiving the response signal A are provided.

On the other hand, in the slave device 2, there is a transmitter/receiver (SR) 2 that transmits and receives the boring signal P and response signal A via the communication path 3.
1, and a polling signal analysis unit (PD) that analyzes the boring signal P transmitted from the main device 1 via the communication path 3.
22, and a response signal creation unit (A) that creates a response signal A corresponding to the analyzed boring signal P and sends it back to the main device 1.
G) 23 is provided corresponding to the communication path 3, and similarly for the communication path 4, a transmitter/receiver (SR) 24, a polling signal analyzer (PD) 25, and a response signal generator (AC) 2 are provided.
6 is provided.

It is now assumed that the switching section 13 connects the boring signal generating section 11 and the response signal analyzing section 12 to the transmitting/receiving section 14 side.

In such a state, the boring signal generation section 11 generates a predetermined 3t.
A boring signal P is created for each lIt, and transmitted to the transmitting/receiving unit 14 via the switching unit 13, and the fault detecting unit 15
to notify the sending of the bowling signal P.

The transmitter/receiver 14 transmits the boring signal P transmitted from the boring signal generator 11 to a downstream communication channel 31 within the communication channel 3.
The information is transmitted to the slave device 2 via.

In the slave device 2, when the transmitter/receiver 21 transmits the boring signal P transmitted from the main device l to the polling signal analyzer 22, the polling signal analyzer 22 analyzes the received boring signal P and sends the analysis result to the response signal. Creation section 23
to communicate.

The response signal creation section 23 creates a response signal A in accordance with the analysis result of the received boring signal P, and transmits it to the transmission/reception section 21 .

The transmitting/receiving unit 21 transmits the transmitted response signal A to the main device 1 via the upstream communication path 32 of the communication path 3.

In the main device 1, the transmitting/receiving section 14 transmits the response signal A transmitted from the slave device 2 to the response signal analysis section 12 via the switching section 13.

The response signal analysis unit 12 analyzes the received response signal A, and notifies the failure detection unit 15 that the response signal A has been received.

Note that if the failure detection unit 15 in the main device 1 is not notified of the reception of the response signal A from the response signal analysis unit 12 within a predetermined period of time after being notified of the sending of the boring signal P from the boring signal generation unit 11, the failure detection unit 15 stops the communication. It is determined that a fault has occurred in the path 3, and a switching signal S1 is transmitted to the switching unit 13, and the boring signal generation unit 11 and response signal analysis unit 12 are switched from the transmitting/receiving unit 14 to the transmitting/receiving unit 17.

Thereafter, the boring signal P created by the polling signal creation section 11 is transmitted to the slave device 2 via the switching section 13, the transmitting/receiving section 17, and the downlink communication path 41 of the communication path 4.

In the slave device 2, the transmitter/receiver 24, the polling signal analyzer 25, and the response signal creator 26 operate in the same manner as described above, and generate a response signal A corresponding to the received polling signal P.
is sent back to the vehicle installation [1] via the upstream communication path 42 of the communication path 4.

Note that even if no failure occurs in the communication channels 3 and 4, the timing unit (TM) 16 switches the switching unit 13 at intervals T (>t) that are longer than the sending cycle of the polling signal P.
A switching signal S2 is transmitted to the communication channels 3 and 4, and the switching unit 13 is alternately connected to the communication channels 3 and 4 in an effort to detect potential failures in the communication channels 3 and 4.

[Problem that the invention seeks to solve]

As is clear from the above description, in a conventional communication system, the failure detection unit 15 in the main device 1 detects a failure occurring in the communication path 3 or 4, but in the slave device 2, the failure detection unit 15 detects a failure occurring in the communication path 3 or 4. There was no means to detect the occurring failure (there was a risk that countermeasures against the failure in the slave device 2 would be delayed).

[Means for solving problems]

FIG. 1 is a diagram showing the principle of the present invention.

In Figure 1, 1 is the main device, 2 is the slave device, 3 and 4
is a redundant communication path connecting the main device 1 and the slave device 2.

100 is a polling signal monitoring means provided in the slave device 2 corresponding to the communication paths 3 and 4 according to the present invention.

[Effect]

The polling signal monitoring means 100 monitors whether or not the polling signal P arrives from the main device 1 within a predetermined period T° via the duplicated communication paths 3 and 4, and A failure occurring in communication path 3 or 4 due to non-arrival is detected. As a result, the reliability of the communication system is improved.

〔Example〕

An embodiment of the present invention will be described below with reference to the drawings.

FIG. 2 is a diagram showing a communication system according to an embodiment of the present invention. Note that the same reference numerals refer to the same objects throughout the plan.

In FIG. 2, failure detection units (FD) 27 and 28
and a timing section (TM) 29 are connected to the communication paths 3 and 4.
Each polling signal monitoring means 100 corresponding to the above is provided.

In FIG. 2, a polling signal P and a response signal are transmitted and received between the main device 1 and the slave device 2 as described above.

Note that the switching section 13 in the main device 1 has a timing section 16.
The polling signal generator 1 alternately switches the communication channels 3 and 4 at predetermined intervals T by the switching signal S2 periodically transmitted from the polling signal generator 1.
1 and the response signal analysis section 12, and establish a communication state. Note that since the interval T is set longer than the period at which the main device 1 sends out the polling signal P,
The polling signal P is transmitted once during each interval T during which the terminal is in communication state.

On the other hand, in the slave device 2, when the polling signal analyzers 22 and 25 receive the polling signal P from the main device 1 via the downlink communication path 31 or 41, the polling signal P is sent to the corresponding failure detector 27 or 28, respectively. Notify of receipt.

Further, the timing section 29 transmits a timing signal to the failure detection sections 27 and 28 at every cycle T' that is twice or more the interval T of the switching signal S2 sent out by the timing section 16.

As mentioned above, in the normal state, the communication channels 3 and 4 alternately repeat the communication state and the non-communication state at every interval T, and the polling signal P is transmitted at least once within the interval T in which they are in the communication state.
Communicate. Therefore, if the failure detection units 27 and 28 have never received a reception notification of the polling signal P from the main device 1 within the interval of the timing signal transmitted from the timing unit 29, the failure detection units 27 and 28 Or, it is determined that a failure has occurred in step 4, and the occurrence of the failure is displayed.

As is clear from the above description, according to the present embodiment, the communication paths 3 and 4 transmit the boring signal P at least once between the timing signals generated by the timing unit 29. In the slave device 2 as well, failures in the communication paths 3 and 4 will be detected.

Note that FIG. 1 is only one embodiment of the present invention, and for example, the number of slave devices 2 connected to the main device 1 is not limited to one set, and it is contemplated that a plurality of sets of slave devices 2 may be connected. However, even in such a case, the effects of the present invention do not change.

〔Effect of the invention〕

As described above, according to the present invention, in the communication system, failures in the communication paths 3 and 4 can be detected even in the slave device 2, and the reliability of the communication system is improved.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing the principle of the present invention, FIG. 2 is a diagram showing a communication system according to an embodiment of the present invention, and FIG. 3 is a diagram showing an example of a conventional communication system. In the figure, ■ is the main device (MST), 2 is the slave device (S
LV), 3 and 4 are communication paths, 11 is a polling signal generation unit (PC), 12 is a response signal analysis unit (AD), 13 is a switching unit (SW), 14.17.21 and 24 are transmission/reception units (SR). ), 15.27 and 28 are fault detection parts (F
D), 16 and 29 are timing parts (TM), 22
25 is a polling signal analyzer (PD), 23 and 26 are response signal generators (AG), 31 and 41 are downlink communication channels, 32 and 42 are uplink communication channels, 100 is a polling signal monitoring means, and A is a response signal , P is a polling signal, sl and s2 are switching signals, 'r. Sword (屓トH月のprincipleshi3 + zutdi, υmonthi=Jru. ヱσ14 customer sysnum rod 2
Oral presentation A 3 stone name system 1000 3 diagrams

Claims (1)

[Claims] A dual communication path (
3 and 4), in which the main device (1) periodically switches and uses the communication path to communicate in a polling format, wherein the slave device (2) is connected to the duplex communication path. (3, 4
), a polling signal monitoring means (100) is provided for monitoring whether or not a polling signal (P) arrives from the main device (1) within a predetermined cycle (T'), A communication path failure detection method, characterized in that a failure occurring in the communication path (3, 4) is detected due to non-arrival of the polling signal (P) within (T').