JPS6213136A - Transmission fault supervisory system - Google Patents

Abstract

PURPOSE:To detect easily an abnormal node by providing a frame detection means outputting a signal displaying the consecution of frames to a constitution controller connecting nodes to a ring communication line at each node, observing simultaneously the display signals by an observing device and comparing them. CONSTITUTION:A reception signal from the ring communication line 3 is inputted to a reception shift register 20 in bit serial. When the frame is received normally, an FE code representing end of frame is satisfied only when the code is shifted to the 0th-8th bit location of the register 20, then a signal RXFRM displays the consecution of the frame. If a byte of incorrect bit constitution is sent due to any fault, a short or a long frame consecutive time is represented in comparison with the output of a frame detection section 10 receiving a normal frame and a node 1 having a possibility of a fault is decided easily by observing the outer signal line 11 of each frame detection section 10 and comparing the result.

Description

[Detailed Description of the Invention] [Summary] This is a method for monitoring transmission failures in a ring-shaped communication path. A configuration control device that connects nodes to a ring-shaped communication path is provided with frame detection means corresponding to each node, which detects communication frames flowing through the communication path and outputs a signal indicating that the wI of the frame is being continued. For example, those display signals,
By observing and comparing them simultaneously with an observation device, abnormal nodes can be easily detected.

[Industrial application field]

The present invention relates to a method for monitoring transmission failures in a ring-shaped communication path of a data communication system.

2. Description of the Related Art A data communication system using a ring-shaped communication path in which a plurality of nodes are connected in series in a ring-like data transmission path is well known.

In a ring-shaped communication path, a failure at one location often affects the entire system, so it is especially desirable to be able to quickly detect the location of the failure.

[Prior art and problems to be solved by the invention] FIG. 3 is a block diagram showing an example of the configuration of a communication system using a ring-shaped communication path.

In the figure, 1 is a node that communicates with each other through this communication system B, and is connected in series to a ring-shaped communication path 3 by a configuration control device 2.

Separately provided ring-shaped communication path 4, ring-shaped communication path 3
This is a path that constitutes a well-known so-called loop hack for constructing a ring excluding the failed part when a failure occurs.

As is well known, when an abnormal state occurs in the ring-shaped communication path 3, the configuration control device 2 determines whether the faulty node 1
By bypassing it as shown in path 5 shown by the dashed line, or by setting a loop hack as shown in path 6, etc.
It has a function to control the configuration of the communication path so that communication can continue.

Each node 1 receives a frame having the structure shown in FIG. 4 (al) transmitted through the ring-shaped communication path 3, and regenerates and relays it as is, or rewrites it with transmission data, etc., and sends it out to the communication path 3. In FIG. 4 (al), FS is the start code of the frame, FE is the end code, and the control information and data to be transmitted are placed in the DT section sandwiched between the two codes.

FS and FB codes, and r) each hide function of the T part, for example, a hide with a 9-bit structure, not shown in FIG. 4 (BL),
They use the 8th pin l- as a control bit, and in general data, the 8th pin is set to a different value from the 6th bit, and the FS
and FB can be distinguished from general data bytes by setting both bits to the same value.

In addition, in a state where no frame is transmitted, fb in Fig. 4
For example, 0 and 1 so that they do not match any byte of l.
Transmit the repetition of .

As mentioned above, frames are regenerated at each node 1, so if one of the nodes 1 has a failure, normal frames will not arrive at each node 1 connected downstream, so the node There is a possibility that mutual communication between F l will become impossible, and such a node 1 needs to be bypassed as soon as possible.

To do this, each configuration control device 2 needs to
Although it is desirable to be able to quickly detect such a phenomenon, conventionally no means for easily performing such detection has been provided.

c.Means for solving problems] FIG. 1 is a block diagram showing the principle configuration of the present invention.

In the figure, 10 indicates a configuration controller 12 for each node I'1.
This is a frame detection unit provided corresponding to the frame detection unit, and outputs a signal indicating that the frame is being continued to the output signal line 11.

[For production]

The frame detection unit 10 detects from the signal of the ring-shaped communication channel 3,
For example, a frame in a predetermined format as described above is detected, and the signal 11 from the start to the end of the frame is output.

By comparing and monitoring each Shingetsu 11 output from the frame detection unit 10 corresponding to each node 1, for example, in the monitoring unit I3, it is possible to easily identify abnormalities based on the differences in frame duration, timing, etc. indicated by them. can be detected.

〔Example〕

FIG. 2 (al is a block diagram showing the configuration of an embodiment of the frame detection section 10 of the present invention, and FIG. 2 (bl is a time chart thereof).

The received signal from the ring-shaped communication path 3 is input into the reception shift register 20 in bit series.

The FS detection gate 21 is connected to the second
When the focus pattern of the FS code in the 1/-me format of FIG. 4 is set at the ~10 bit position (
The bit value in this state (shown above the dashed line in the receive shift register 20) turns on the output line 22.

Output line 22 causes flip-flop 2 to be activated in the next cycle.
In the next cycle, the output FSPTN of the flip-flop 24 is turned on, and in the next cycle, the so-called JK type flip-flop 25 is turned on and held. Its output RXFI? H turns on the output CRXFM of the flip-flop 26.

The output RXFRM is output to the output signal line 11 to indicate that the frame is continuing.

The counter 27 is constantly counting repeatedly from 0 to 8, but the output ps of the flip-flop 24 is
By turning n on, °8 is forcibly set regardless of the count value at that time, and FS is set in the next cycle.
When D is turned off, counting restarts from "0".

The counter 27 has a binary display output line 28, so its 23 111 output line 11XCN3, /JJ, 7
1- value '8' (becomes y phono when D.

The 6th and 8th gates 71 of the receiving shift register 20 are input to the exclusive OR (FOR) game 129, so if both inputs are 0 or both 1, the output of the gate 2B will be 0. . Its negative output NDP is the signal CRX group and I? X(I) is input to the AND (A) gate 30 along with lJ3, and the output of the AND gate 30 is sent to the flip-flop 25.
Serves as a reset input.

Therefore, after CRXFM is turned on, counter 27
When the count value of
When the 6th and 8th bits of 0 become the same value (an example of the focus value in this state is shown below the dashed line in the receive shift register 20), the flip-flop 25 is reset and l
? XFRM is restored off.

As is clear from the frame structure and the bit structure of each byte, this condition is such that when the frame is normally received, the FE code indicating the end of the frame is placed in the O-th to 8th bit positions of the reception shift register 20. signal +7XFIIM indicates the duration of the frame.

Therefore, for example, if R is triggered by the rise of FRM, I? When the XFRM is turned on, the duration of the frame is observed, and if this observation is compared for the output signal line 11 of each frame detection unit 10 corresponding to each node 1, if everything is in a normal state, all frames should be observed as the same m duration.

However, if a byte with an incorrect bit configuration that differs from the frame configuration is transmitted due to some kind of failure,
Frame detection in which the frame is received normally, such as FS code is not detected, non-FS code signal is incorrectly identified as FS code, FE code is not detected, reset input of flip-flop 25 is generated with general data byte, etc. The possibility that the RXFRM signal is controlled at a timing different from that of the unit 10 increases.

Therefore, a shorter or longer frame duration is indicated compared to the output of the frame detection unit 10 from which a normal frame is received, and the output signal line 11 of each frame detection unit 10 is observed and compared. By doing so, it is possible to easily determine the node 1 that may have a failure.

[Effects of the Invention] As is clear from the above description, according to the present invention, in a communication system using a ring-shaped communication path, it is easy to monitor the nodes connected to the configuration control device and determine a faulty node. Therefore, by speeding up the response to failures, etc., there is a significant industrial effect of improving the availability of the communication system.

[Brief explanation of the drawing]

Figure 1 is a block diagram showing the principle configuration of the present invention, Figure 2
al is a block diagram of an embodiment of the present invention; FIG. 2 is a time chart; FIG. 3 is a block diagram of a communication system; is a node, 2.12 is a configuration controller, 3
．． 4 is a ring-shaped communication path, 10 is a frame detection section, 11 is an output signal line, 13 is a monitoring section, 20 is a reception shift register, 21 is an F
S detection gate, 23.24.25.26 is a flip-flop, 27 is a counter, 29 is an exclusive OR gate,
□30 is an AND gate

Claims (1)

[Scope of Claims] A ring-shaped communication path (3) formed by connecting one or more configuration control devices (12) in series, the ring-shaped communication path (3) comprising one or more configuration control devices (12) connected in series.
) connects one or more nodes (1) to the ring-shaped communication channel (3)
In a communication system configured to be connected to, the configuration control device (12) is provided with frame detection means (10) corresponding to each of the nodes (1), and the frame detection means (10) is configured to: A transmission failure monitoring system characterized in that it is configured to detect a communication frame of a predetermined format and output a signal (11) indicating that the communication frame is continuing.