JP2021022760A - Communication path monitoring device and communication path monitoring method - Google Patents

Abstract

To solve the problem in a network for transmitting/receiving data using duplex communication paths, where when abnormality occurs in one communication path, a location at which the abnormality has occurred cannot be identified immediately.SOLUTION: A monitoring device 3 comprises: a path monitoring unit 31 that by using processing of transmitting, to devices connected to communication paths to be monitoring targets, transmission data for monitoring states of two routes of the communication paths connecting the devices with the monitoring device so that the transmission data is transmitted to each of the two routes of the communication paths and receiving return data returned from respective devices having received the transmission data so that the return data is received from each of the two routes of the communication paths, determines that a route of the communication paths from which reception of the return data is successful is normal and determines that a route of the communication paths from which reception of the return data is not successful is abnormal; a monitoring information storage unit 33 that as monitoring information, stores a determination result of normality or abnormality obtained by the path monitoring unit 31 performing determination for each communication path; and a monitoring information output unit 34 that outputs the monitoring information in a form in which a communication path whose abnormality is determined can be identified.SELECTED DRAWING: Figure 2

Description

The present invention relates to a communication path monitoring device and a communication path monitoring method.

Conventionally, there is a control system in which a single or a plurality of communication control devices capable of transmitting a control command or the like to a control device via a network controls a single or a plurality of control devices via the network. In this control system, transmission control such as a control command to be transmitted to a network is performed by using PRP (Parallel Redundancy Protocol) control.

In a network using PRP control, two communication paths are provided between the communication control device and the communication device. When an abnormality occurs in one of the two communication paths, the recovery time for recovering the communication path in which the abnormality has occurred can be set to zero due to the characteristics of PRP control. Due to this characteristic, the communication route monitoring has adopted a method in which an abnormality display is output only when an abnormality occurs in both routes.

As a technique for monitoring a communication path, for example, a technique disclosed in Patent Document 1 is known. In Patent Document 1, when determining an abnormality in a communication path based on the presence or absence of a response of a slave station to the communication of a master station, it is possible to distinguish whether the abnormality is due to a transmission path or a reception path. The monitoring device is disclosed.

JP-A-2017-120960

In the PRP control, for the purpose of stabilizing communication, an abnormality is displayed when both of the two communication paths provided between the monitoring device and the communication device become abnormal. Therefore, even if an abnormality occurs in one communication path, if the other communication path is normal, it is determined that both of the two communication paths are normal. As a result, there is a problem that the discovery of an abnormality occurring in one of the communication paths is delayed.

Further, even if an abnormality occurs in the communication path between the communication devices, it takes time to identify the location where the abnormality has occurred. Therefore, it was not possible to take effective measures against the communication path in which the abnormality occurred.

Then, even if it is possible to distinguish whether an abnormality has occurred in the transmission path or the reception path by the technique disclosed in Patent Document 1, when a network is formed by connecting a plurality of communication devices, which communication path is used. Could not detect if an abnormality occurred in.

The present invention has been made in view of such a situation, and an object of the present invention is to quickly identify a location where an abnormality has occurred even when an abnormality occurs in one of the communication paths.

The communication path monitoring device according to the present invention transmits 2 transmission data for monitoring the state of two communication paths connecting the device and the own device to the device connected to the communication path to be monitored. The communication path of the system that was able to receive the reply data is judged to be normal by the process of transmitting for each communication path of the system and receiving the reply data returned from the device that received the transmission data for each of the two communication paths. , A route monitoring unit that determines that the communication path of the system that cannot receive reply data is abnormal, and a monitoring information storage unit that stores the judgment result of normal or abnormal judgment determined by the route monitoring unit for each communication route as monitoring information. It is provided with a monitoring information output unit that outputs monitoring information in a form capable of identifying a communication path determined to have occurred.

According to the present invention, since the monitoring information is output in a form in which the communication path determined to have an abnormality can be identified, the location of the abnormality occurring in one of the duplicated communication paths can be quickly identified. It becomes possible to specify to.
Issues, configurations and effects other than those described above will be clarified by the following description of the embodiments.

It is a block diagram which shows the basic structure example of the control system which concerns on one Embodiment of this invention. It is a block diagram which shows the internal structure example of the monitoring apparatus which concerns on one Embodiment of this invention. It is a block diagram which shows the hardware configuration example of the computer which concerns on one Embodiment of this invention. It is a block diagram which shows the whole structure example of the control system which concerns on one Embodiment of this invention. It is a figure which shows the example which the abnormality occurred in the communication path between the protection relay device and the communication device which concerns on one Embodiment of this invention. It is a figure which shows the example which the protection relay device which concerns on one Embodiment of this invention transmits and receives a monitoring frame with a plurality of other protection relay devices. It is a figure which shows the example which the abnormality occurred in the communication path between the communication device and the communication device which concerns on one Embodiment of this invention. It is a flowchart for demonstrating the processing of the communication path monitoring function performed by the protection relay device which concerns on one Embodiment of this invention. It is a figure which shows the display example of the monitoring information which concerns on one Embodiment of this invention.

Hereinafter, embodiments for carrying out the present invention will be described with reference to the accompanying drawings. In the present specification and the drawings, components having substantially the same function or configuration are designated by the same reference numerals, and redundant description will be omitted.

[One Embodiment]
First, a configuration example of a transmission system according to an embodiment of the present invention will be described.
FIG. 1 is a block diagram showing a basic configuration example of the control system 100. FIG. 1 describes a basic configuration example of a PC (Personal Computer) 1, a monitoring device 3, and communication devices 10 and 11 used in the control system 100.

The control system 100 according to the present embodiment has a function of transmitting data by PRP control, for example, in Ethernet (registered trademark) using a general IO bus including an optical cable and an optical converter. Then, the control system 100 has a communication device for connecting the devices, and the communication device transmits / receives data transmitted between the devices, for example, a specific frame (transmission frame or reception frame). It is possible to do.

For example, the control system 100 includes a PC 1, a monitoring device 3, and communication devices 10 and 11. Both the PC 1 and the monitoring device 3 have a LAN (Local Area Network) port, and are connected by a LAN cable 2.

The monitoring device 3 has an optical converter, and the monitoring device 3 and the communication devices 10 and 11 are connected by two optical cables 4S and 4R, respectively. The monitoring device 3 transmits a transmission frame from the optical cable 4S and receives a reply frame from the optical cable 4R. Then, the monitoring device 3 and the communication device 10 are connected by the communication path L1A of the first system, and the monitoring device 3 and the communication device 11 are connected by the communication path L2A of the second system. The communication paths L1A and L2A are each composed of an optical cable 4S in which a transmission frame is transmitted from the monitoring device 3 and an optical cable 4R in which the monitoring device 3 receives a reception frame. The optical cables 4S and 4R are examples of LAN cables for connecting the monitoring device 3 and the communication devices 10 and 11 by LAN.

The PC 1 is an example of an information processing device used by a worker who uses the control system 100. The PC 1 instructs the monitoring device 3 to monitor the communication path according to the input of the worker. Then, the PC 1 acquires the monitoring information of the optical cables 4S and 4R in the communication path of each system from the monitoring device 3, and displays the monitoring information on the display device 45 (see FIG. 3 described later). Therefore, the worker who operates the PC 1 can check the communication status of the optical cables 4S and 4R and the status of the monitoring device 3.

The control system 100 monitors an abnormality occurring in the communication path between the monitoring device 3 and the plurality of communication devices 10 and 11 connected to the monitoring device 3 by the abnormality monitoring function of the communication path included in the monitoring device 3. It is possible. Therefore, the monitoring device 3 periodically transmits a transmission frame used for monitoring the normality or abnormality of the communication path to the communication devices 10 and 11. Further, the communication devices 10 and 11 that have received the transmission frame transmit the reply frame to the monitoring device 3. By confirming the reception of the reply frame from the communication devices 10 and 11, the monitoring device 3 can confirm that no abnormality has occurred in the communication paths L1A and L2A to the communication devices 10 and 11, that is, it is normal. In addition, the monitoring device 3 can also notify the PC 1 of an abnormality that has occurred in the optical cables 4S and 4R that have occurred in each communication path.

For example, it is assumed that an abnormality occurs in the optical cable 4S in the communication path L2A of the second system. The occurrence of an abnormality in the optical cable 4S is indicated by adding a cross mark to the optical cable 4S of the communication path L2A. In this case, the frame transmitted by the monitoring device 3 to the communication device 11 does not reach the communication device 11. Therefore, the communication device 11 does not transmit the reply frame to the monitoring device 3. If the monitoring device 3 cannot receive the reply frame from the communication device 11 even after waiting for a certain period of time or longer, the monitoring device 3 determines that an abnormality has occurred in the communication path L2A. In this case, the monitoring device 3 notifies the PC1 that an abnormality has occurred in the communication path L2A. Therefore, the worker can grasp that the abnormality has occurred in the communication path L2A through the PC1.

FIG. 2 is a block diagram showing an example of the internal configuration of the monitoring device 3.
The monitoring device 3 includes a route monitoring unit 31, a conversion unit 32, a monitoring information storage unit 33, and a monitoring information output unit 34.

The route monitoring unit 31 monitors the route of the optical cables (optical cables 4S and 4R of each communication path) connected to the monitoring device 3. Therefore, the route monitoring unit 31 monitors the state of the two communication paths connecting the device and the own device with respect to the device connected to the communication path to be monitored (transmission data). (Example) is transmitted for each of the two communication paths. Then, the route monitoring unit 31 receives the reply frame (an example of reply data) returned from the device that received the transmission frame for each of the two communication paths, and the communication path of the system that could receive the reply frame. Is judged to be normal, and the communication path of the system that cannot receive the reply frame is judged to be abnormal.

Therefore, the route monitoring unit 31 transmits a transmission frame to a communication device close to the own device, and communicates from the own device when the reply frame returned to the transmission frame cannot be received from the communication device as the destination. The communication path to the device is judged to be abnormal. In the following description, both the transmission frame transmitted to the device directly connected to the monitoring device 3 via one communication path and the reply frame returned from this device are referred to as "link frames". In the present embodiment, since the devices directly connected to the monitoring devices 3 are the communication devices 10 and 11, the monitoring device 3 transmits and receives link frames to and from the communication devices 10 and 11.

For example, the route monitoring unit 31 transmits a link frame to the communication devices 10 and 11 through the optical cable 4S in the communication path of each system, and the link frame from the communication devices 10 and 11 through the optical cable 4R in the communication path of each system. Wait for a reply. Then, when the route monitoring unit 31 can receive the link frame returned by the communication devices 10 and 11, it determines that there is no abnormality in the communication path of the system that received the link frame. On the other hand, when the route monitoring unit 31 cannot receive the link frame returned by the communication devices 10 and 11, it determines that there is an abnormality in the communication path of the system that could not receive the link frame. The route monitoring unit 31 writes in the monitoring information storage unit 33 as monitoring information whether or not there is an abnormality in the communication path for which the presence or absence of an abnormality has been determined.

Further, the route monitoring unit 31 transmits a transmission frame to another communication route monitoring device as a destination. Then, when the route monitoring unit 31 cannot receive the reply frame returned to the transmission frame from the other communication route monitoring device as the destination, the route monitoring unit 31 connects the first communication device to which the own device is connected and another communication path. The communication path to and from the second communication device to which the monitoring device is connected is determined to be abnormal. In the following description, a frame transmitted / received to / from a device connected to the monitoring device 3 via two or more communication paths is referred to as a “monitoring frame”. In the present embodiment, since the device connected to the monitoring device 3 via two or more communication paths is another monitoring device 3 (see FIG. 1), the monitoring device 3 is different from the other monitoring device 3. Send and receive monitoring frames between.

For example, the route monitoring unit 31 transmits a monitoring frame to a monitoring device 3 other than the monitoring device 3 through the communication path of each system, and waits for a reply of the monitoring frame from the other monitoring device 3. Then, when the route monitoring unit 31 can receive the monitoring frame returned by the other monitoring device 3, it determines that there is no abnormality in the communication path between the plurality of communication devices of the system that received the monitoring frame. On the other hand, when the route monitoring unit 31 cannot receive the monitoring frame returned by the other monitoring device 3, it determines that there is an abnormality in the communication path between the plurality of communication devices of the system that could not receive the monitoring frame. .. The route monitoring unit 31 writes in the monitoring information storage unit 33 as monitoring information whether or not there is an abnormality in the communication path for which the presence or absence of an abnormality has been determined.

The conversion unit 32 converts the transmission frame transmitted by the route monitoring unit 31 to the optical cable 4S into an optical signal, and sends the transmission frame composed of the optical signal to the optical cable 4S of each communication path. Further, the conversion unit 32 converts a reception frame composed of an optical signal received through the optical cable 4R of each communication path connected to the communication device or another communication path monitoring device into an electric signal, and the path monitoring unit 31 receives the signal. Is possible. The route monitoring unit 31 can determine whether or not the reception frame can be received by taking in the reception frame converted into the electric signal from the conversion unit 32.

The monitoring information storage unit 33 stores the determination result of normality or abnormality determined by the route monitoring unit 31 for each communication route as monitoring information.

The monitoring information output unit 34 outputs monitoring information in a form capable of identifying a communication path determined to have an abnormality. The monitoring information is output to the PC 1 and displayed on the display device 45 of the PC 1 (see FIG. 3 described later). A detailed example of the monitoring information displayed on the PC 1 is shown in FIG. 9 described later.

Next, the hardware configuration of the computer 4 constituting each device of the control system 100 will be described.
FIG. 3 is a block diagram showing a hardware configuration example of the computer 4.

The computer 4 is hardware used as a computer that can operate as a PC 1 or a monitoring device 3. The computer 4 includes a CPU (Central Processing Unit) 41, a ROM (Read Only Memory) 42, and a RAM (Random Access Memory) 43, which are connected to the bus 44, respectively. Further, the computer 4 includes a display device 45, an input device 46, a non-volatile storage 47, and a network interface 48.

The CPU 41 reads the program code of the software that realizes each function according to the present embodiment from the ROM 42, loads it into the RAM 43, and executes the program code. Variables and parameters generated during the arithmetic processing of the CPU 41 are temporarily written in the RAM 43, and these variables and parameters are appropriately read by the CPU 41. For example, the functions of the route monitoring unit 31 and the monitoring information output unit 34 of the monitoring device 3 are realized by the CPU 41 included in the monitoring device 3. Further, the PC 1 realizes a function of outputting a monitoring instruction to the monitoring device 3, receiving monitoring information from the monitoring device 3, and processing it into a tabular form. An arithmetic processing device such as an MPU (Micro Processing Unit) may be used instead of the CPU 41.

The display device 45 is, for example, a liquid crystal display monitor, and displays the result of processing performed by the computer 4 to the worker. For example, a keyboard, a mouse, or the like is used as the input device 46, and an operator can perform predetermined operation inputs and instructions. For example, in the PC 1, the monitoring information output from the monitoring device 3 can be displayed on the display device 45. The monitoring device 3 and the communication devices 10 and 11 do not have to include the display device 45 and the input device 46.

As the non-volatile storage 47, for example, HDD (Hard Disk Drive), SSD (Solid State Drive), flexible disk, optical disk, optical magnetic disk, CD-ROM, CD-R, magnetic tape, non-volatile memory and the like are used. Be done. In the non-volatile storage 47, in addition to the OS (Operating System) and various parameters, a program for operating the computer 4 is recorded. The ROM 42 and the non-volatile storage 47 permanently record programs, data, and the like necessary for the CPU 41 to operate, and are a computer-readable non-transient recording medium that stores the programs executed by the computer 4. It is used as an example. For example, the monitoring information storage unit 33 of the monitoring device 3 is used as a database built in the non-volatile storage 47.

For the network interface 48, for example, a NIC (Network Interface Card) or the like is used, and various data can be transmitted and received between the devices via a LAN, a dedicated line, or the like connected to the terminals of the NIC. For example, the PC 1 and the monitoring device 3 have a LAN port to which the LAN cable 2 can be connected as a network interface 48. Further, as the network interface 48, for example, there is an optical converter capable of transmitting and receiving an optical signal frame to the optical cables 4S and 4R connected to the communication devices 10 and 11. The function of the conversion unit 32 of the monitoring device 3 can be realized by the network interface 48.

Next, based on the basic configuration example of the control system 100 shown in FIGS. 1 to 3, the communication path of the network constructed between the protection relay device having the function of the monitoring device 3 and the plurality of communication devices is monitored. A configuration example of the control system 101 and an example of an abnormality monitoring process will be described with reference to FIGS. 4 to 9.

FIG. 4 is a block diagram showing an overall configuration example of the control system 101.
The control system 101 includes three PCs 1A to 1C, three protection relay devices 3A to 3C, and six communication devices 10A to 10C and 11A to 11C. In the control system 101, each communication device is connected by an optical cable to form an Ethernet network. The configurations and functions of PC1A to 1C, protection relay devices 3A to 3C, and communication devices 10A to 10C and 11A to 11C correspond to the configurations and functions of PC1, monitoring device 3, and communication devices 10 and 11, respectively shown in FIG. ..

The protection relay devices 3A to 3C are devices that protect an electric circuit by detecting an abnormal state such as a short circuit or a ground fault that has occurred in, for example, a power system or a power facility. Hereinafter, the protection relay device 3A that monitors the communication path will be described with attention.

In the control system 101, the protection relay devices 3B and 3C (an example of the own device) other than the protection relay device 3A (an example of the own device) are connected to the two communication paths to be monitored by the path monitoring unit 31 of the protection relay device 3A. An example of another communication path monitoring device) and a communication device for transmitting and receiving data between the protection relay device 3A and the protection relay devices 3B and 3C are provided.

PC1A is connected to the protection relay device 3A. Similarly, the protection relay device 3B is connected to the PC1B, and the protection relay device 3C is connected to the PC1C. Similar to the monitoring device 3 shown in FIG. 1, the protection relay devices 3A to 3C each have a function of monitoring two communication paths.

Further, the protection relay devices 3A to 3C each include an optical converter and a connection port capable of transmitting and receiving a link frame to and from the communication device. In the figure, the connection port to which the optical cable of the communication path of the first system is connected is referred to as "CH1", and the connection port connected to the optical cable of the communication path of the second system is referred to as "CH2". CH1 and CH2 each represent a communication path system and are also called channel numbers.

The communication device 10A is connected to CH1 of the protection relay device 3A via the communication path L1A, and the communication device 11A is connected to CH2 via the communication path L2A. Similarly, the communication device 10B is connected to CH1 of the protection relay device 3B via the communication path L1B, and the communication device 11B is connected to CH2 via the communication path L2B. Further, the communication device 10C is connected to CH1 of the protection relay device 3C via the communication path L1C, and the communication device 11C is connected to CH2 via the communication path L2C.

Further, the communication devices 10A and 10B are connected by the communication path L11, and the communication devices 10B and 10C are connected by the communication path L12. Further, the communication devices 11A and 11B are connected by the communication path L21, and the communication devices 11B and 11C are connected by the communication path L22. Therefore, the adjacent devices are connected to each other so as to be able to communicate with each other via the communication path.

The communication paths L1A to L1C, L2A to L2C, L11, L12, L21, and L22 shown in FIGS. 4 and 4 are all configured by optical cables 4S and 4R as shown in FIG. However, in order to avoid complicating the drawings, the optical cables 4S and 4R in the communication paths of each system are shown together in one communication path.

First, an operation example in which the protection relay device 3A determines whether the communication paths L1A and L2A connecting the protection relay device 3A and the communication devices 10A and 11A are normal or abnormal will be described.

When the route monitoring unit 31 of the protection relay device 3A transmits the link frame F1 from CH1 to the communication device 10A through the communication path L1A, the communication device 10A returns the link frame F2 through the communication path L1A. When the route monitoring unit 31 of the protection relay device 3A confirms that the communication device 10A has returned the link frame F2, it determines that the communication path L1A is normal.

Further, when the route monitoring unit 31 of the protection relay device 3A transmits the link frame F1 from CH2 to the communication device 11A through the communication path L2A, the communication device 11A returns the link frame F2 through the communication path L2A. When the route monitoring unit 31 of the protection relay device 3A confirms that the communication device 11A has returned the link frame F2, it determines that the communication path L2A is normal.

The same processing as that performed by the protection relay device 3A is also performed by the protection relay devices 3B and 3C. When the route monitoring unit 31 of the protection relay device 3B transmits the link frame F1 (not shown) from CH1 to the communication device 10B through the communication path L1B, the communication device 10B returns the link frame F2 (not shown) through the communication path L1B. When the route monitoring unit 31 of the protection relay device 3B confirms that the communication device 10B has returned the link frame F2, it determines that the communication path L1B is normal.

Further, when the route monitoring unit 31 of the protection relay device 3B transmits the link frame F1 (not shown) from CH2 to the communication device 11B through the communication path L2B, the communication device 11B returns the link frame F2 (not shown) through the communication path L2B. To do. When the route monitoring unit 31 of the protection relay device 3B confirms that the communication device 11B has returned the link frame F2, it determines that the communication path L2B is normal.

As for the protection relay device 3C, the communication paths L1C and L2C are normal by transmitting the link frame F1 (not shown) and confirming the returned link frame F2 (not shown) in the same manner as the protection relay devices 3A and 3B. The process of determining that is performed.

The processing of the protection relay devices 3B and 3C may be performed at the same timing as the protection relay device 3A. For example, the processing is cyclically performed as in the protection relay devices 3A, 3B, 3C, 3A .... You may. That is, one protection relay device transmits the monitoring frame F11 and receives the monitoring frame F12 by the number of (total number of devices-1) during one cycle, which is the period for performing the route monitoring.

FIG. 5 is a diagram showing an example in which an abnormality occurs in the communication path L1A between the protection relay device 3A and the communication device 10A.

As shown by adding an X mark to the communication path L1A in the figure as an abnormality occurrence location X1, when an abnormality occurs in the communication path L1A, the protection relay device 3A loses the link frame F1 transmitted to the communication device 10A. .. In this case, since the communication device 10A cannot reply to the link frame F1, the protection relay device 3A cannot receive the link frame F2 returned from the communication device 10A. The fact that the link frame F2 is not transmitted from the communication device 10A is represented by a one-dot chain line in the figure as a vanishing frame N1. Therefore, the route monitoring unit 31 of the protection relay device 3A writes to the monitoring information storage unit 33 that an abnormality has occurred in the communication path L1A.

No abnormality has occurred in the communication path L2A between the protection relay device 3A and the communication device 11A. Therefore, when the protection relay device 3A transmits the link frame F1 to the communication device 11A, the protection relay device 3A can receive the link frame F2 returned by the communication device 11A. Therefore, the route monitoring unit 31 of the protection relay device 3A writes to the monitoring information storage unit 33 that the communication path L2A is normal.

Further, the protection relay devices 3B and 3C can also receive the link frame F2 which is a reply to the link frame F1 transmitted to each communication device connected to the own device. Therefore, the route monitoring unit 31 of the protection relay devices 3B and 3C writes to the monitoring information storage unit 33 of the protection relay devices 3B and 3C that the communication path is normal, respectively.

Next, a process in which the protection relay device 3A transmits a monitoring frame to other protection relay devices 3B and 3C that are not directly connected to diagnose the presence or absence of an abnormality in the communication path between the communication devices will be described.

FIG. 6 is a diagram showing an example in which the protection relay device 3A transmits and receives a monitoring frame to and from other protection relay devices 3B and 3C.

Normally, the protection relay device 3A transmits the monitoring frame F11 which is the same data to the protection relay device 3B and the protection relay device 3C through the two paths of CH1 and CH2. The monitoring frame F11 includes a device number for identifying another protection relay device as a destination.

In the protection relay device 3B and the protection relay device 3C, when the monitoring frame F11 is received, the path monitoring unit 31 included in the protection relay device 3B and the protection relay device 3C determines the device number. Then, when the route monitoring unit 31 confirms that the monitoring frame F11 is destined for its own device, the route monitoring unit 31 processes the monitoring frame F11. As the processing of the monitoring frame F11, the route monitoring unit 31 performs, for example, a process of storing the time when the monitoring frame F11 is received and creating a monitoring frame F12 which is a reply of the monitoring frame F11.

For example, the protection relay device 3A transmits the monitoring frame F11 to the communication path of the first system through CH1. The monitoring frame F11 transmitted by the protection relay device 3A from CH1 to the protection relay device 3B as a destination reaches the protection relay device 3B via the communication paths L1A, L11, and L1B.

Upon receiving the monitoring frame F11, the protection relay device 3B transmits the monitoring frame F12 from CH1 to the protection relay device 3A as a destination. The monitoring frame F12 reaches the protection relay device 3A via the communication paths L1B, L11, and L1A. Therefore, the route monitoring unit 31 of the protection relay device 3A determines that the communication paths L1A, L11, and L1B are normal.

Similarly, the monitoring frame F11 transmitted by the protection relay device 3A from CH1 to the protection relay device 3C as a destination reaches the protection relay device 3C via the communication paths L1A, L11, L12, and L1C. Upon receiving the monitoring frame F11, the protection relay device 3C transmits the monitoring frame F12 from CH1 to the protection relay device 3A as a destination. The monitoring frame F12 reaches the protection relay device 3A via the communication paths L1C, L12, L11, and L1A. Therefore, the route monitoring unit 31 of the protection relay device 3A determines that the communication paths L1A, L11, L12, and L1C are normal.

Further, the protection relay device 3A transmits the monitoring frame F11 to the communication path of the second system through CH2. The monitoring frame F11 transmitted by the protection relay device 3A from CH2 to the protection relay device 3B as a destination reaches the protection relay device 3B via the communication paths L2A, L21, and L2B. Upon receiving the monitoring frame F11, the protection relay device 3B transmits the monitoring frame F12 from CH2 to the protection relay device 3A as a destination. The monitoring frame F12 reaches the protection relay device 3A via the communication paths L2B, L21, and L2A. Therefore, the route monitoring unit 31 of the protection relay device 3A determines that the communication paths L2A, L21, and L2B are normal.

Similarly, the monitoring frame F11 transmitted by the protection relay device 3A from CH2 to the protection relay device 3C as a destination reaches the protection relay device 3C via the communication paths L2A, L21, L22, and L2C. Upon receiving the monitoring frame F11, the protection relay device 3C transmits the monitoring frame F12 from CH2 to the protection relay device 3A as a destination. The monitoring frame F12 reaches the protection relay device 3A via the communication paths L2C, L22, L21, and L2A. Therefore, the route monitoring unit 31 of the protection relay device 3A determines that the communication paths L2A, L21, L22, and L2C are normal.

Also, for the protection relay devices 3B and 3C, the communication path is normal by transmitting the monitoring frame F11 to the protection relay devices other than the own device and receiving the monitoring frame F12 from the other protection relay devices. Determine if it exists. In this case as well, for example, the protective relay devices 3A, 3B, 3C, 3A ... may be cyclically processed. That is, one protection relay device transmits the monitoring frame F11 and receives the monitoring frame F12 by the number of (total number of devices-1) during one cycle, which is the period for performing route monitoring. ..

FIG. 7 is a diagram showing an example in which an abnormality occurs in the communication path L11 between the communication device 10A and the communication device 10B.

As shown by adding a cross mark to the communication path L1A of the first system in the figure as an abnormality occurrence location X2, when an abnormality occurs in the communication path L11, the protection relay device 3A changes from CH1 to the protection relay devices 3B and 3C. The monitoring frame F11 transmitted to the user disappears. In this case, the protection relay devices 3B and 3C cannot receive the monitoring frame F11 transmitted by the protection relay device 3A in the communication path of CH1.

Further, since the protection relay devices 3B and 3C cannot reply to the monitoring frame F11 in the communication path of CH1, the protection relay device 3A cannot receive the monitoring frame F12 returned from the protection relay devices 3B and 3C. The fact that the monitoring frame F12 is not transmitted from the communication device 10A is represented by a one-dot chain line in the figure as a vanishing frame N2.

The route monitoring unit 31 of the protection relay device 3A writes to the monitoring information storage unit 33 that an abnormality has occurred in the communication path L11. Then, the monitoring information output unit 34 of the protection relay device 3A has an abnormality display information indicating that an abnormality has occurred in the communication path of CH1 of the protection relay device 3B, and an abnormality has occurred in the communication path of CH1 of the protection relay device 3C. Outputs abnormal display information indicating that.

On the other hand, since the protection relay devices 3B and 3C cannot receive the monitoring frame F11 from the communication path of CH1 of the protection relay device 3A, the abnormality display information indicating that an abnormality has occurred in the communication path of CH1 is output. If each protection relay device has already been monitored between the protection relay device and the communication device by the link frames F1 and F2 shown in FIG. 4, it can be determined that the connection between the protection relay device and the communication device is normal. Therefore, the protection relay device can determine that the communication path L11 is abnormal.

Here, if an abnormality occurs only in the communication path L12 (not shown), the protection relay device 3A can receive the monitoring frame F12 returned from the protection relay device 3B, but cannot receive the monitoring frame F12 from the protection relay device 3B. Therefore, the route monitoring unit 31 of the protection relay device 3A writes to the monitoring information storage unit 33 that an abnormality has occurred in the communication path L12. In this case, the monitoring information output unit 34 of the protection relay device 3A outputs abnormality display information indicating that an abnormality has occurred in the communication path of CH1 of the protection relay device 3C.

Then, no abnormality has occurred in the communication paths L21 and L22 of the second system. Therefore, when the protection relay device 3A transmits the monitoring frame F11 from CH2 to the protection relay devices 3B and 3C, the protection relay device 3A can receive the monitoring frame F12 returned by the protection relay devices 3B and 3C. Therefore, the route monitoring unit 31 of the protection relay device 3A writes to the monitoring information storage unit 33 that the communication paths L21 and L22 are normal.

Similarly, in the protection relay devices 3B and 3C, if the monitoring frame F11 is transmitted from CH1 and CH2 to the other protection relay devices and the monitoring frame F12 returned from the other protection relay devices cannot be received, the communication devices are used. It can be determined that an abnormality has occurred in the communication path of. Then, the route monitoring unit 31 of the protection relay devices 3B and 3C, like the route monitoring unit 31 of the protection relay device 3A, checks the normality or abnormality of each communication path in the monitoring information storage unit 33 of the protection relay devices 3B and 3C. Write to.

FIG. 8 is a flowchart for explaining the processing of the communication path monitoring function performed by the protection relay device 3A. The process shown in FIG. 8 is similarly performed in the other protection relay devices 3B and 3C.

First, the route monitoring unit 31 of the protection relay device 3A transmits the link frame F1 from CH1 to the communication device 10A next to the protection relay device 3A, and transmits the link frame F1 from CH2 to the communication device 11A. (S1).

Next, the route monitoring unit 31 determines whether or not there is a reply from the communication device 10A to the link frame F2 (S2). If there is no reply from the communication device 10A to the link frame F2 (NO in S2), the route monitoring unit 31 determines that the communication path L1A between the protection relay device 3A and the communication device 10A has an abnormality (S3). For example, when an abnormality occurs in the communication path L1A as shown in FIG. 5, the link frame F2 is not returned from the communication device 10A. Therefore, the route monitoring unit 31 writes the determination result of determining the communication path L1A as abnormal in the monitoring information storage unit 33.

If there is a reply from the communication device 10A to the link frame F2 (YES in S2), the route monitoring unit 31 determines whether or not there is a reply from the communication device 11A to the link frame F2 (S4). If there is no reply from the communication device 11A to the link frame F2 (NO in S4), the route monitoring unit 31 determines that the communication path L2A between the protection relay device 3A and the communication device 11A has an abnormality (S5). Then, the route monitoring unit 31 writes the determination result of determining the communication path L2A as abnormal in the monitoring information storage unit 33.

If there is a reply from the communication device 11A to the link frame F2 (YES in S4), the route monitoring unit 31 transmits the monitoring frame F11 from CH1 to the protection relay devices 3B and 3C (S6).

Next, the route monitoring unit 31 determines whether or not there is a reply from the monitoring frame F12 from the protection relay device 3B (S7). If there is no reply from the protection relay device 3B to the monitoring frame F12 (NO in S7), the route monitoring unit 31 connects the protection relay device 3A and the protection relay device 3B based on the channel number for which the monitoring frame F12 did not reply. It is determined that the communication path L11 or L21 between them is abnormal (S8).

For example, when an abnormality occurs in the communication path L11 as shown in FIG. 7, the monitoring frame F12 is not returned from the protection relay devices 3B and 3C. Therefore, the protection relay device 3A cannot receive the monitoring frame F12 from CH1. When the protection relay device 3A cannot receive the monitoring frame F12 from the plurality of protection relay devices in this way, the route monitoring unit 31 determines that the communication path L11 has an abnormality as a result of determining the communication path L11. Write to 33.

When an abnormality occurs in the communication path L12, the protection relay device 3B returns the monitoring frame F12, but the protection relay device 3C does not return the monitoring frame F12. Therefore, the monitoring frame F12 that the protection relay device 3A can receive from CH1 is limited to the one transmitted from the protection relay device 3B. Therefore, the route monitoring unit 31 writes in the monitoring information storage unit 33 that an abnormality has occurred in the communication path L12 as a determination result of the communication path L12.

If there is a reply from the protection relay device 3B to the monitoring frame F12 (YES in S7), the route monitoring unit 31 determines whether or not there is a reply from the protection relay device 3C to the monitoring frame F12 (S9). If there is no reply from the monitoring frame F12 from the protection relay device 3C (NO in S9), the route monitoring unit 31 connects the protection relay device 3A and the protection relay device 3C based on the channel number for which the monitoring frame F12 did not reply. It is determined that the communication path L12 or L22 between them is abnormal (S10). Then, the route monitoring unit 31 writes the determination result of determining the communication paths L12 and L22 as abnormal in the monitoring information storage unit 33.

If there is a reply from the protection relay device 3C to the monitoring frame F12 (YES in S9), the route monitoring unit 31 determines that all communication paths are normal (S11). Then, the route monitoring unit 31 writes the determination result of determining that all the communication routes are normal in the monitoring information storage unit 33, and ends this process.

FIG. 9 is a diagram showing a display example of monitoring information.

The monitoring information output unit 34 shown in FIG. 2 reads out the determination result for each communication path system from the monitoring information storage unit 33, and the communication path from the own device to the communication device and the first communication device and the second communication device. A screen showing the determination result of the communication path between the two is output to the display device 45 of the PC1. Further, the monitoring information output unit 34 outputs the position of the communication path whose determination result is abnormal to the screen. The screen including the monitoring information is displayed on the display devices 45 of the PCs 1A to 1C, respectively.

For example, as monitoring information, a list in which the device numbers of the protection relay devices are arranged vertically and the channel numbers of the protection relay devices are arranged horizontally is displayed on the display device 45 of the PC1. In this list, the device number "1" is referred to as the protection relay device 3A, the device number "2" is referred to as the protection relay device 3B, and the device number "3" is referred to as the protection relay device 3C. Further, the channel numbers are assigned as "CH1" and "CH2" corresponding to the two-channel connection ports of the protection relay device.

In the list on the upper side of FIG. 9, if the communication path is normal, the round mark lights up (represented by a black circle), and if the communication path is abnormal, the mark does not light up (represented by a white circle). For example, when the protection relay device 3A cannot send and receive the link frames F1 and F2 to and from the communication device 10A through the communication path L1A of CH1, the mark does not light up in the item of CH1 of the device number "1". Therefore, it can be seen that an abnormality has occurred in the communication path L1A. Further, the position of the communication path whose determination result is abnormal is displayed as "abnormality occurrence location: communication path L1A".

Since an abnormality has occurred in the communication path L1A, the protection relay device 3A cannot send and receive monitoring frames F11 and F12 to and from other protection relay devices. Therefore, the mark does not light up in the item of CH1 of the device numbers "2" and "3".

Further, as shown in the lower list of FIG. 9, if the protection relay device 3A can send and receive the link frames F1 and F2 to and from the communication devices 10A and 11A, the item of CH1 and CH2 of the device number "1" is displayed. The mark lights up.

On the other hand, as shown in FIG. 7, when an abnormality occurs in the communication path L11 in CH1 between the communication devices 10A and 10B, the protection relay device 3A and the protection relay devices 3B and 3C pass through the communication path L11 or L12 of CH1. The monitoring frames F11 and F12 cannot be transmitted and received between them. Therefore, the mark does not light up in the item of CH1 of the device numbers "2" and "3". However, if the communication paths L21 and L22 in CH2 between the communication devices 10A and 10B are normal, the marks are lit in the items of CH2 of the device numbers "2" and "3". Further, the position of the communication path whose determination result is abnormal is displayed as "abnormality occurrence location: communication path L11".

The display form of the list showing the monitoring information in this way makes it easier for the worker to determine whether the communication path is normal or abnormal. In addition to the list, the name of the communication path in which the abnormality has occurred may be displayed in text.

In the control system 101 according to the embodiment described above, when monitoring the communication paths of two systems in which communication is performed using PRP control, the protection relay device communicates with the communication device or another protection relay device. By transmitting and receiving two types of frames, it is determined whether the communication path is normal or abnormal. Then, since the determination result of the communication path is displayed as abnormality information on the PC, the worker who operates the PC can immediately grasp the abnormality occurring in the communication path and deal with the abnormality.

Here, the route monitoring unit 31 of the protection relay device transmits and receives a link frame between the communication device adjacent to the own device, and transmits the link frame from the communication path of the system between the protection relay device and the communication device. If it cannot be received, it can be determined that an abnormality has occurred in the communication path of this system. Further, the route monitoring unit 31 of the protection relay device transmits / receives a monitoring frame to / from another protection relay device connected via the plurality of communication devices, and a communication path of the system between the plurality of communication devices. If the monitoring frame cannot be received from, it can be determined that an abnormality has occurred in the communication path of this system.

In this way, the route monitoring unit 31 of the protection relay device can determine the abnormalities that have occurred in the communication path between the protection relay device and the communication device and the communication path between the plurality of communication devices. The PC connected to each protection relay device displays as abnormality display information whether or not an abnormality has occurred determined by the route monitoring unit 31 of the protection relay device. Therefore, the worker who operates the PC can grasp the communication path where the abnormality has occurred at an early stage.

[Modification example]
The number of protection relay devices constituting the control system 101 may be four or more. In this case, in the flowchart of FIG. 8, the process of step S6 is the process of transmitting the monitoring frame from the own device to all the other protection relay devices. Then, as in steps S7 and S9, the route monitoring unit 31 performs a process of confirming whether or not the monitoring frame has been received from another protection relay device, and if the monitoring frame cannot be received, it is determined that the communication path is abnormal. do it.

In addition, for each PC connected to the protection relay device, not only the monitoring information related to the protection relay device to which the PC is connected is displayed, but also the monitoring information is collected from a plurality of PCs, and the communication path of the entire control system 101 An integrated PC capable of displaying the determination result of determining the normality or abnormality of the above may be provided. The determination result displayed by the integrated PC enables the worker to grasp the state of the entire communication path of the control system 101 in detail without collecting monitoring information from a plurality of PCs.

Further, the monitoring device 3 shown in FIG. 1 and the communication devices 10A and 11A may be connected by an electric cable. In this case, the monitoring device 3 shown in FIG. 2 may not have a conversion unit 32 capable of converting an electric signal into an optical signal. Further, the protection relay devices 3A to 3C shown in FIG. 4 may also have a configuration that does not have the conversion unit 32.

It should be noted that the present invention is not limited to the above-described embodiment, and it goes without saying that various other application examples and modifications can be taken as long as the gist of the present invention described in the claims is not deviated.
For example, the above-described embodiment describes the configuration of the system in detail and concretely in order to explain the present invention in an easy-to-understand manner, and is not necessarily limited to the one including all the described configurations. Further, it is also possible to add, delete, or replace a part of the configuration of the present embodiment with another configuration.
In addition, the control lines and information lines indicate those that are considered necessary for explanation, and do not necessarily indicate all the control lines and information lines in the product. In practice, it can be considered that almost all configurations are interconnected.

1 ... PC, 3 ... Monitoring device, 3A to 3C ... Protection relay device, 10, 11 ... Communication device, 10A to 10C, 11A to 11C ... Communication device, 31 ... Route monitoring unit, 32 ... Conversion unit, 33 ... Monitoring information Storage unit, 34 ... Monitoring information output unit, 45 ... Display device, 100, 101 ... Control system, F1, F2 ... Link frame, F11, F12 ... Monitoring frame

Claims (7)

To the device connected to the communication path to be monitored, transmission data for monitoring the status of the two communication paths connecting the device and the own device is transmitted for each of the two communication paths. By the process of receiving the reply data returned from the apparatus that received the transmission data for each of the two communication paths, it is determined that the communication path of the system that could receive the reply data is normal, and the reply is made. A route monitoring unit that determines that the communication path of the system that cannot receive data is abnormal,
A monitoring information storage unit that stores normal or abnormal determination results determined by the route monitoring unit as monitoring information for each communication path.
A communication path monitoring device including a monitoring information output unit that outputs the monitoring information in a form capable of identifying the communication path determined that the abnormality has occurred. As the device, a communication path monitoring device other than the own device and a communication device for transmitting and receiving the transmission data between the own device and the other communication path monitoring device are provided.
The route monitoring unit transmits the transmission data to the communication device close to the own device, and when the reply data to the transmission data cannot be received from the communication device as the destination, the communication from the own device. The communication path monitoring device according to claim 1, wherein the communication path to the device is determined to be abnormal. The route monitoring unit transmits the transmission data to the other communication path monitoring device as a destination, and when the reply data to the transmission data cannot be received from the other communication path monitoring device as the destination, the own device. The communication path monitoring device according to claim 2, wherein the communication path between the first communication device to which the other communication path monitoring device is connected and the second communication device to which the other communication path monitoring device is connected is determined to be abnormal. The monitoring information output unit reads out the determination result for each system of the communication path from the monitoring information storage unit, the communication path from the own device to the communication device, the first communication device, and the second communication. The communication path monitoring device according to claim 3, wherein a screen showing the determination result in the communication path between the devices is output to the display device. The communication path monitoring device according to claim 4, wherein the monitoring information output unit outputs the position of the communication path whose determination result is abnormal to the screen. Further, the transmission data transmitted by the route monitoring unit is converted into an optical signal and sent to the communication path, and the reply data received from the communication device or the other communication path monitoring device is converted into an electric signal and described. The communication path monitoring device according to claim 5, further comprising a conversion unit that can be received by the route monitoring unit for each system of the communication path. To the device connected to the communication path to be monitored, transmission data for monitoring the status of the two communication paths connecting the device and the own device is transmitted for each of the two communication paths. Processing and
A process of receiving reply data returned from each of the devices that received the transmission data for each of the two communication paths, and
A process of determining that the communication path of the system that can receive the reply data is normal, and determining that the communication path of the system that cannot receive the reply data is abnormal.
A process of storing the normal or abnormal judgment result as monitoring information in the monitoring information storage unit for each communication path.
A communication route monitoring method including a process of outputting the monitoring information in a form capable of identifying the communication route determined to have caused the abnormality.

Images