JP4419617B2 - Fault location determination method for multi-loop network - Google Patents

Description

  In the present invention, for example, in a ring network such as a LAN having a ring topology, a control network, etc., each station cyclically transmits (broadcasts) a frame addressed to all stations, and each station receives it and transmits it in a transmission frame. The present invention relates to a technique effective when applied to a failure location determination technique or the like in a network system that recognizes identification information of an original station number.

  As a ring network, various networks are known in addition to a token ring and FDDI. As described above, in a system in which the transmission right is periodically and periodically circulated by a method such as token circulation, the stations can regularly recognize each other. For example, a station that does not transmit for a certain period is considered to have dropped from the ring for some reason. Thereby, the actual configuration information on the ring can be recognized and updated.

  In order to improve the reliability of the line, a plurality of methods for duplicating the transmission line of the loop network are known. As a typical example, when an abnormality occurs or a fault location is detected, such as FDDI, There is a so-called loopback method in which a transmission line is ensured by turning back a line in a station (for example, Patent Document 1). In addition, two lines are operated in parallel, the transmitting station transmits the same frame to both, and each station that relays and receives selects and receives one of the input frames by a method such as first-come-first-served basis. The method of doing is known.

  As described above, in a network with duplicated lines, it is generally possible to continue the transmission function as before even if a single failure or abnormality occurs. In other words, the logical station connection configuration existing on the network can be made redundant so as not to be affected by a physical failure at one location, thereby improving reliability.

  In such a system that requires high reliability, for example, as in Patent Document 2, it is common not to leave the network monitoring function to a specific dedicated node, but to distribute the function to make it redundant. It is. Although it can be said that transmission can be continued if a failure occurs at one location, the operation of the entire network system cannot be continued if a subsequent failure occurs unless the situation is resolved promptly. is there.

  That is, in Patent Document 2, in a system composed of a plurality of nodes connected to a duplex ring-shaped line, a frame is transmitted from a unique node in the ring called a boundary node, and other general nodes are When the relay relay operation of the frame sent out by the node is performed and the frame reception from the upstream node is interrupted, the substitute frame with its own node number is sent out, and it is not possible to detect the round of its own node frame. A frame with information added is transmitted, and this frame is received by a specific network monitoring node to make a failure determination.

  Such a redundant network is often used in a high-reliability control system configured by connecting control devices such as programmable controllers to each other, and recognizes failure points early in a preventive maintenance sense. It can be said that it is a very important function.

  In such a control network system, each node is often arranged on the system, for example, in a panel, under the floor, or incorporated in a device. Therefore, detection of abnormal locations is displayed on display devices such as personal computers, displays, and touch panel display systems, not on the LED display attached to the control device or network adapter body, and placed in a place that is easily monitored by the central control room and maintenance personnel. There is a need to do. Generally, these display devices are used by connecting to any of the nodes. Therefore, in order to increase the degree of freedom in system construction, the failure location is the same regardless of which node is connected to the display device. It is desirable to be able to do so.

However, when the failure determination function is fixedly assigned to a specific node as in the case of Patent Document 2 described above, there arises a problem that the degree of freedom in system configuration, change, and the like is impaired.
JP-A-61-70833 JP 2001-189738 A

  An object of the present invention is to provide a technique capable of realizing preventive maintenance by early recognition of a failure location without impairing the degree of freedom of system construction in a loop network with a redundant configuration.

According to a first aspect of the present invention, a plurality of loop-type transmission lines whose information transmission directions are opposite to each other and a plurality of the loop-type transmission lines are connected to the plurality of loop-type transmission lines simultaneously when transmitting the information. A plurality of node devices that transmit and receive one of the plurality of loop transmission lines when receiving the information, and a failure location determination method for a multi-loop network including:
The actual configuration information in which each of the node devices records other node devices observed to exist on each of the loop-shaped information transmission paths is always stored in the reverse direction to each of the plurality of loop transmission paths together with the information. A first step of simultaneously transmitting and exchanging and sharing with other node devices;
In any of the node devices, based on the setting configuration information in which the node device that should originally exist on each loop information transmission path and the actual configuration information are recorded, on each loop information transmission path A second step of identifying the fault location;
Only including,
The setting configuration information is composed of a first bit string in which the presence / absence of each of the node devices that should originally exist on each of the loop information transmission paths is assigned to 1 bit (Yes: 1, No: 0),
The actual configuration information is composed of a second bit string in which the presence / absence of each node device on each loop information transmission path is assigned to 1 bit (Yes: 1, No: 0),
In the second step, for each of the loop information transmission lines, an exclusive OR of a plurality of the second bit strings observed by each of the node devices and the first bit string is calculated. ,
If the bit string of the exclusive OR is not all 0, the node device corresponding to the bit position of 1 in the exclusive OR is regarded as a failure,
When the bit string of the exclusive OR is all 0,
For each individual loop information transmission path, the logical product of the plurality of second bit strings observed in each of the node devices is taken, and when the logical product and the first bit string match, the loop information transmission is performed. When it is determined that there is no failure in the path and the logical product and the first bit string do not match, there is a failure in the loop information transmission path upstream of the node device corresponding to the 1 bit position of the logical product. Provided is a method for determining a fault location in a multi-loop network that is considered to have occurred .

In the above-described present invention, each node device can be provided with a function of visualizing and displaying a failure location or a function of outputting information on the failure location to the outside.
As described above, according to the present invention, in each of a plurality of node devices connected to the redundant multiple loop information transmission lines, not only the other node devices and loop information transmission lines are monitored, but also the current operation is performed. Since the actual configuration information in which the node device is confirmed to be exchanged and shared as a bit string, for example, is provided in each node device with a function of determining a failure location by logical operation of this bit string. It is possible to realize preventive maintenance by early recognition of the failure location without being affected by multiple failures of the node device.

  In addition, since it is possible to arbitrarily select which node device is used to determine the failure location, it is possible to realize preventive maintenance by early recognition of the failure location without impairing the degree of freedom of system construction.

  According to the present invention, it is possible to realize preventive maintenance by early recognition of a failure location without impairing the freedom of system construction in a redundant loop network.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
FIG. 1 is a conceptual diagram illustrating an example of a configuration of a multi-loop network that implements a failure location determination method according to an embodiment of the present invention. FIG. 2 illustrates determination of a failure location in the multi-loop network. FIG. 3 is a conceptual diagram showing an example of the configuration of the actual configuration station information table used in the initial state, FIG. 3 is a conceptual diagram showing an example of the frame format of an information frame used in this multi-loop network, and FIGS. FIG. 6 is a conceptual diagram showing an example of the operation of the multi-loop network according to the present embodiment when a failure of the node device occurs. FIGS. 6 and 7 illustrate the operation of the multi-loop network according to the present embodiment when a transmission line fails. FIG. 8 is a block diagram showing an example of a configuration of a node device constituting the multi-loop network according to the present embodiment.

  As illustrated in FIG. 1, the multi-loop network system of the present embodiment includes a plurality of A-system lines 11 (loop-shaped information transmission paths) and B-system lines 12 (loop-shaped) whose information transmission directions are opposite to each other. Information transmission path), and a plurality of stations connected to the loop information transmission path 10 to exchange information via the A system line 11 and the B system line 12 (Node device 20).

  In the example of FIG. 1, a network in which the maximum number of stations (the number of node devices 20) is 10 stations (station numbers 9 to 0) is simplified, and the configuration in which station 0, station 8, and station 9 do not exist is the initial configuration. The case where it is an original setting structure is illustrated. Further, in the actual system configuration, the station connections are not necessarily arranged in order, so an example in which they are arranged in random order is shown.

  The setting configuration station information 50 (setting configuration information) illustrated on the upper side of FIG. 2 is information for storing the initial setting configuration of FIG. 1, and is the number of bits corresponding to each station (in this case, 9 to 0). (10 bits). 1 of each bit (presence flag) indicates that the station exists in the initial state, and 0 indicates that the station does not exist in the initial state.

In other words, the set configuration station information 50 indicates configuration station information in which the system designer has set a station that should exist as a system, and all the stations have the same information.
2 is an example of the actual configuration station information table 60 (actual configuration information) held by each station. In the actual configuration station information table 60, the actual configuration station information 63 exchanged between the stations includes the A-system actual configuration for all the stations 9 to 0 that are the transmission sources of the actual configuration station information 63 (actual configuration information). Stored in the station information 61 and the B-system actual configuration station information 62.

  That is, the actual configuration station information 63 indicates that each station has a fault or failure of another station for each A system line 11 and B system line 12 from the initial setting state indicated by the setting configuration station information 50 described above. It is a bit string exchanged with other stations by recording together the observation results that the other stations cannot be recognized due to disconnection of the transmission path between the stations. 1 in each bit indicates that another station corresponding to each bit has been observed from the station, and 0 indicates that it has not been observed.

  Since the actual configuration station information 63 individually holds / transmits observation results of other stations in each of the A system line 11 and the B system line 12, the data amount of the actual configuration station information 63 to be added is the maximum number of stations. × 2 bits (20 bits in this embodiment).

  As illustrated in FIG. 8, the node device 20 constituting each station has a microprocessor 21 that controls the whole and the microprocessor 21 to control a failure location as described later, Dual port in which data such as the control program 21a that realizes a function for transmitting and receiving information necessary for determination processing, the above-described setting configuration station information 50, actual configuration station information table 60, and the determination result of the fault location are stored. A memory 22 and a transmission / reception circuit 23 for transmitting / receiving information to / from the loop information transmission path 10 are provided.

  The transmission / reception circuit 23 includes a buffer memory 24 in which transmission / reception data is temporarily stored, a transmission / reception selection unit 25 that switches between transmission lines of the A-system line 11 and the B-system line 12, and an A-system. An A-system transmission / reception circuit 26 that transmits / receives data to / from the line 11 and a B-system transmission / reception circuit 27 that transmits / receives data to / from the B-line 12 are configured.

  The microprocessor 21 controls the transmission / reception circuit 23 to transmit data from the transmission / reception circuit 23 to both the A-system line 11 and the B-system line 12 at the time of data transmission, and at the time of data reception, the A-system line 11 and the B-system line. 12 is selected and data is taken in.

  Each node device 20 is configured to be connectable to an information processing device 40 such as an external personal computer via a host I / F 42 such as a system bus, for example, from the information processing device 40 side. Information such as a determination result of a failure location stored in the dual port memory 22 can be read and displayed on the display 41 provided in the information processing apparatus 40, for example.

  Although not particularly illustrated, a display may be provided in the node device 20 itself to display information such as the setting configuration station information 50, the actual configuration station information table 60, and the determination result of the failure location.

  As illustrated in FIG. 3, the frame 30 that carries information exchanged between the plurality of node devices 20 via the loop information transmission path 10 is a start delimiter 31 for identifying the head of the frame 30. A frame header 32 for storing address information of the source and destination node device 20 of the frame 30 and a frame type, transmission data 33 carried in the frame 30, error detection / correction of the frame 30 A frame check code 35 for detecting the end of the frame 30, and an end delimiter 36 for identifying the end of the frame 30.

  Furthermore, in the case of the present embodiment, the frame 30 includes an actual configuration station information unit 34 in which the actual configuration station information 63 observed in the node device 20 (stations 0 to 9) that is the transmission source of the frame 30 is stored. Is provided.

  That is, each station always adds the actual configuration station information 63 observed from its own station at the time of transmission to the end of the transmission data 33 and transmits it. On the receiving side, each station transmits the received actual configuration station information 63 to the set configuration station. By storing the information 50 in correspondence with each of the A-system line 11 and the B-system line 12 of the entry of the transmission source station, the actual configuration station information 63 is exchanged between the stations.

  FIG. 4 shows a state at the time of occurrence of an abnormality in which the station 5 has dropped from the initial state of FIG. 1, and FIG. 5 stores the actual configuration station information 63 of the A system line 11 and the B system line 12 of each station at that time. The state of the actual configuration station information table 60 is shown.

  6 shows a state in which a physical disconnection has occurred between the station 5 and the station 7 from the initial state of FIG. 1, and FIG. 7 shows an A system line 11 and a B system line 12 of each station in that case. The actual configuration station information table 60 in which the actual configuration station information 63 is stored is shown.

  In the initial state immediately after the setting configuration station information 50 is set, the entry corresponding to each station in each of the A-system actual configuration station information 61 and the B-system actual configuration station information 62 in the actual configuration station information table 60 is set configuration station information. It is initialized with 50 bit strings.

  When each station acquires the transmission right, each station transmits a frame 30 addressed to all the stations (broadcast), and the other stations receive the frame 30 while relaying the received frame 30 from upstream to downstream. It is assumed that the frame 30 that has returned around the ring is deleted at the transmission source, and the transmission right passes to the next station. The transmission always transmits the same frame 30 to both the A-system line 11 and the B-system line 12 at the same time, and the receiving station receives from both systems and selects one of them to capture.

  For example, in FIG. 1, the frame 30 transmitted by the station 1 flows in the direction of station 6 → station 3 → station 5 in the A system, and finally returns to the station 1. In the B system, the flow proceeds from station 2 to station 4 to station 7, and finally returns to station 1. Each station relays the received frame 30 while receiving it.

  As shown in FIGS. 1, 2, 4, 5, 6, and 7, when a certain station exists as seen from each station, the bit position corresponding to the station number of that station in the actual configuration station information 63 The existence flag is set to 1, and the existence flag is set to 0 when it does not exist. The actual configuration station information 63 exchanged with each other is stored in an actual configuration station information table 60 possessed by each station.

The presence flag is set to 1 when reception of a broadcast frame from the station is confirmed for a certain period, and is set to 0 when it is not confirmed continuously three times or more, for example.
Assuming that the number of connected stations is finite, the actual configuration station information 63 is a binary number whose number of digits is equal to the maximum number of connected stations for each of the duplicated rings (A system line 11 and B system line 12). It can be shown.

  Now, as shown in FIG. 4, when a station (for example, the station 5) becomes faulty (dropped state), the frame 30 does not flow to the downstream station of the faulty part. The state of the actual configuration station information 63 of the A system line 11 and the B system line 12 is as shown in FIG.

  Also, as shown in FIG. 6, when one location is physically disconnected, the frame 30 does not flow to the downstream station at the failure location, so the A-system line 11 of the duplex ring in the actual configuration station information table 60, The state of the actual configuration station information 63 of the B system line 12 is as shown in FIG.

  Using the values of the actual configuration station information 63 collected from all stations existing in these rings and stored in the actual configuration station information table 60 and the values of the set configuration station information 50, the failure location is determined by the following method. Can be determined.

Step 1: An exclusive logical sum of the logical sum of the actual configuration station information 63 of the A system line 11 and the B system line 12 of the own station and the set configuration station information 50 is calculated and is defined as α.
Step 2: If α ≠ 0, it is considered that the station corresponding to the position where the bit of α stands is dropped (in the cases of FIGS. 4 and 5, the bit of α corresponding to the station 5 is 1, It is determined that the station 5 has dropped out).

Step 3: If α = 0, the following processing is performed for all areas of the actual configuration station information 63 collected from all stations on both the A-system line 11 and the B-system line 12.
(Processing a): The area of the station that is not registered in the set configuration station information 50 is all 1 bits.

(Processing a): The area of the station registered in the set configuration station information 50 is left as it is.
(Processing c): After (Processing a) and (Processing a), all areas are logically ANDed vertically. The result of this logical product is defined as a value β. A system value is Aβ and B system value is Bβ.

(Processing D): Aβ and Bβ are compared with the set configuration station information 50.
When Aβ or Bβ matches the set configuration station information 50, there is no fault on the line in the system. When the two do not match, the standing bit position indicates one station number. In this case, it is considered that a physical failure has occurred in the line upstream of this station number (in the cases of FIGS. 6 and 7, it is assumed that there is no failure because Aβ and the set configuration station information 50 match, and Bβ Since the setting configuration station information 50 does not match, it is considered that a line failure has occurred on the upstream side of the station 5 at the bit position that does not match.

  As described above, in this embodiment, each individual station (node device 20) has an actual configuration station information table 60 in which the actual configuration station information 63 exchanged with each other is stored. In this case, it is possible to always detect the failure location as described above. For this reason, the information processing device 40 is connected to an arbitrary station, and the detection result of the fault location is read. For example, the dropped station is marked with an X mark and displayed on the display 41 for system management. Can be presented to a person. Further, the bitmap itself of the actual configuration station information table 60 may be output or displayed as necessary.

  That is, since it is possible to arbitrarily select which station (node device 20) is used to determine the failure location, prevention by early recognition of the failure location without impairing the degree of freedom of system construction such as the arrangement of individual stations. Maintenance can be realized.

  FIG. 9 shows a modification of the node device. In the modification of FIG. 9, a PLC system 70 configured by industrial control equipment such as a programmable controller is connected as a station connected to the loop information transmission path 10. The PLC system 70 is connected to the node unit 73 connected to the loop information transmission path 10 and the network I / F 43 of the external information processing apparatus 40 via an information network such as a LAN (Local Area Network) 44. It comprises a network I / F 72 and a processor unit 71 that controls them.

  The node unit 73 has a function equivalent to that of the node device 20 described above, and the processor unit 71 reads out information such as the determination result of the failure location stored in the memory in the node unit 73, and the network I / F 72 and the LAN 44. The information processing device 40 performs processing for visualizing and displaying the read information such as the determination result of the failure location on the display 41.

  In the PLC system 70 such as industrial control equipment, it is common that resources such as processor performance and memory are suppressed to be low due to cost and other constraints. In the method, the set configuration station information 50 and the actual configuration station information table 60 of several tens to several hundred bits are provided to the individual PLC system 70, and only a small logical operation is performed. It can be easily realized at low cost.

  As described above, according to the present embodiment, in the multiplexed ring network including the loop information transmission line 10 multiplexed by the A system line 11 and the B system line 12, a failure has occurred in one place. In that case, the location can be determined explicitly, facilitating maintenance, facilitating system management, improving preventive maintenance, and further improving reliability.

  Further, as described above, since only the actual configuration station information 63 that can be recognized in each station and the setting configuration station information 50 that is the same setting in the entire system are used in the calculation of determining the failure location, the failure location can be easily obtained. Can be determined. Even if the functions of the present embodiment are installed in the network terminal equipment constituting each station, the processing related to transmission of the network terminal equipment is not compressed, and the conventional monitoring function and failure diagnosis are concentrated. Compared to the system, the processing can be distributed and the same function can be realized, so the reliability is improved, the availability of fault diagnosis information is improved, and the necessary information is available no matter which node the display device is connected to As a result, the flexibility of system construction is also improved.

It is a conceptual diagram which shows an example of a structure of the multiple loop type network which implements the failure location determination method which is one embodiment of this invention. It is a conceptual diagram which shows an example of the structure of the initial state of the real structure station information table used for the determination of the failure location in this multiple loop type network. It is a conceptual diagram which shows an example of the frame format of the information frame used with this multiple loop type network. It is a conceptual diagram which shows an example of an effect | action of the multi-loop type network at the time of a failure of a node apparatus. FIG. 5 is an explanatory diagram showing an example of the contents of an actual configuration station information table corresponding to the failure state of FIG. 4. It is a conceptual diagram which shows an example of an effect | action of the multiple loop type network at the time of the failure of a transmission line. It is explanatory drawing which shows an example of the content of the real structure station information table corresponding to the failure state of FIG. It is a block diagram which shows an example of a structure of the node apparatus which comprises the multiple loop type network which is one embodiment of this invention. It is a block diagram which shows the modification of the node apparatus in the multiple loop type network which is one embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Loop information transmission path 11 A system line 12 B system line 20 Node apparatus 21 Microprocessor 22 Dual port memory 23 Transmission / reception circuit 24 Buffer memory 25 Transmission / reception selection part 26 A system transmission / reception circuit 27 B system transmission / reception circuit 30 Frame 31 Start delimiter 32 Frame header 33 Transmission data 34 Actual configuration station information section 35 Frame check code 36 End delimiter 40 Information processing apparatus 41 Display 42 Host I / F
43 Network I / F
44 LAN
50 Setting Configuration Station Information 60 Actual Configuration Station Information Table 61 A System Real Configuration Station Information 62 System B Real Configuration Station Information 63 Real Configuration Station Information 70 PLC System 71 Processor 72 Network I / F
73 Node part

Claims (2)

A plurality of loop-type transmission lines whose information transmission directions are opposite to each other and a plurality of the loop-type transmission lines are transmitted simultaneously to the plurality of loop-type transmission lines when transmitting the information, and a plurality of information are transmitted when receiving the information. A plurality of node devices that select and receive any one of the loop type transmission lines, and a fault location determination method for a multiple loop type network,
The actual configuration information in which each of the node devices records other node devices observed to exist on each of the loop-shaped information transmission paths is always stored in the reverse direction to each of the plurality of loop transmission paths together with the information. A first step of simultaneously transmitting and exchanging and sharing with other node devices;
In any of the node devices, based on the setting configuration information in which the node device that should originally exist on each loop information transmission path and the actual configuration information are recorded, on each loop information transmission path A second step of identifying the fault location;
Only including,
The setting configuration information is composed of a first bit string in which the presence / absence of each of the node devices that should originally exist on each of the loop information transmission paths is assigned to 1 bit (Yes: 1, No: 0),
The actual configuration information is composed of a second bit string in which the presence / absence of each node device on each loop information transmission path is assigned to 1 bit (Yes: 1, No: 0),
In the second step, for each of the loop information transmission paths, an exclusive OR of a plurality of the second bit strings observed by each of the node devices and the first bit string is calculated. ,
If the bit string of the exclusive OR is not all 0, the node device corresponding to the bit position of 1 in the exclusive OR is regarded as a failure,
When the bit string of the exclusive OR is all 0,
For each individual loop information transmission path, the logical product of the plurality of second bit strings observed in each of the node devices is taken, and when the logical product and the first bit string match, the loop information transmission is performed. When it is determined that there is no failure in the path and the logical product and the first bit string do not match, there is a failure in the loop information transmission path upstream of the node device corresponding to the 1 bit position of the logical product. A fault location determination method for a multi-loop network characterized in that the occurrence of a fault occurs .   The failure location of the multi-loop network according to claim 1, further comprising a third step of visualizing and displaying information on the failure location obtained in the second step in any of the node devices. Judgment method.

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