JP7388585B1 - Information processing device, information processing method, information processing program, and distributed control system - Google Patents

Abstract

An object of the present invention is to prevent a control node of a DCS from becoming overloaded. A management server 30 according to an embodiment includes a calculation section 332 and a notification section 333. The calculation unit 332 calculates the load of each of the plurality of control nodes 10 based on information indicating the status of data access to each of the plurality of control nodes 10. The notification unit 333 provides notification when the load of any one of the plurality of control nodes 10 exceeds a threshold value. [Selection diagram] Figure 2

Description

The present invention relates to an information processing device, an information processing method, an information processing program, and a distributed control system.

BACKGROUND ART Conventionally, a distributed control system (DCS) in which a plurality of control nodes connected to each other via a network control a plant has been known (for example, see Patent Document 1).

Special table 2017-511024 publication

However, the conventional DCS has a problem in that it may not be possible to prevent the control node from becoming overloaded.

When OPC-UA is used for communication between control nodes, an inquiry is made to a GDS (Global Discovery Server). For example, an inquiry to the GDS is made for the purpose of authentication between control nodes and to know which control nodes have data that the HMI (Human Machine Interface) server wants to access.

Although the GDS is queried only once, due to the characteristics of process control, data access is constantly performed on the control node, and the same load continues to be applied to the control node. Data access includes acquisition of monitoring data by the HMI server, acquisition of process nodes by the control node, communication between control nodes, and the like.

One aspect is to prevent the DCS control node from becoming overloaded.

The information processing device according to one aspect includes a calculation unit that calculates a load of each of the plurality of control nodes based on information indicating a status of data access to each of the plurality of control nodes; The present invention is characterized by comprising a notification unit that issues a notification when the load exceeds a threshold value.

The information processing method according to one aspect calculates the load of each of the plurality of control nodes based on information indicating the status of data access to each of the plurality of control nodes, and calculates the load of each of the plurality of control nodes. The computer is characterized in that the computer executes a process of notifying when the threshold value is exceeded.

The information processing program according to one aspect calculates the load of each of the plurality of control nodes based on information indicating the status of data access to each of the plurality of control nodes, and calculates the load of each of the plurality of control nodes. It is characterized by causing the computer to execute a process of notifying when the threshold value is exceeded.

A distributed control system according to one aspect includes a management server that notifies a data access destination in response to an inquiry, a plurality of control nodes, and a monitoring server, wherein the plurality of control nodes are The monitoring server makes an inquiry to the management server and mutually accesses data in response to a notification from the management server. The management server includes a calculation unit that calculates the load of each of the plurality of control nodes based on information indicating the status of data access to each of the plurality of control nodes; The present invention is characterized by comprising a notification unit that provides notification when the load of any one of the plurality of control nodes exceeds a threshold value.

According to one embodiment, it is possible to prevent the control node of the DCS from becoming overloaded.

1 is a diagram showing a configuration example of a distributed control system according to a first embodiment; FIG. FIG. 2 is a diagram illustrating a configuration example of a management server according to the first embodiment. FIG. 3 is a diagram showing an example of task information. FIG. 3 is a diagram showing an example of data access. FIG. 3 is a diagram showing an example of data access. It is a flowchart which shows the flow of processing of a management server. FIG. 2 is a diagram illustrating an example of a hardware configuration.

DESCRIPTION OF EMBODIMENTS Below, embodiments of an information processing device, an information processing method, an information processing program, and a distributed control system disclosed in the present application will be described in detail based on the drawings. Note that the invention of the present application is not limited to the embodiments described here. In addition, the same elements are given the same reference numerals, and redundant explanations will be omitted as appropriate. Moreover, each embodiment can be combined as appropriate within a consistent range. Further, the management server is an example of an information processing device.

The configuration of the distributed control system of the first embodiment will be explained using FIG. 1. FIG. 1 is a diagram illustrating a configuration example of a distributed control system according to a first embodiment.

As shown in FIG. 1, the distributed control system 1 includes a control node 10a, a control node 10b, a control node 10, a field device 21a, a field device 22a, a management server 30, an HMI client 40, and an HMI server 50.

In the following description, each control node may be referred to as the control node 10 without distinction. Furthermore, in the following description, each field device may be referred to as field device 20 without distinction.

The number of control nodes 10 and field devices 20 included in the distributed control system 1 is not limited to what is shown in FIG. Further, one or more field devices 20 may be connected to each of the control nodes 10, or no field device 20 may be connected to each control node 10.

Field device 20 is provided in the plant. The plant is, for example, an oil plant, a petrochemical plant, a chemical plant, or a gas plant. When the plant is in operation, products such as LNG (liquefied natural gas), resins (plastics, nylon, etc.), and chemical products can be obtained.

In addition, a plant includes factory facilities, mechanical facilities, production facilities, power generation facilities, storage facilities, facilities at the wellhead where oil, natural gas, etc. are extracted. The plant is also equipped with equipment for producing products.

Field device 20 acquires information regarding the state of the plant. For example, the field device 20 is a temperature sensor, a pH sensor, a speed sensor, an acceleration sensor, an atmospheric pressure sensor, a gas concentration sensor, a device that detects the opening of a valve, a device that detects the state of a switch (on or off), etc. .

The field device 20 transmits data indicating sensor values or detection results to the control node 10 using a predetermined communication protocol.

The control node 10 executes assigned tasks. A task is part or all of a calculation that occurs when an application is executed. For example, a task is a function, a function block (FB), a function module, etc. included in an application. Note that the task may use data received from the field device 20.

Note that the control APP (control application) shown in FIG. 1 is an application for executing tasks.

Further, the control node 10a, the control node 10b, and the control node 10c each store data 110a, data 110b, and data 110c. The data 110a, the data 110b, and the data 110c may be data obtained from the field device 20, or may be data obtained by executing a task.

The management server 30 is connected to the control node 10 via a network. The management server 30 functions as a GDS (reference URL: https://jp.opcfoundation.org/wp-content/uploads/sites/2/2018/12/4_Endo_OPCUA_GDS.pdf). GDS manages the list of OPC-UA applications and the certificates used by the applications.

Furthermore, the management server 30 functions as an Alias. Alias corresponds to the name resolution function of DNS (Domain Name System) in an IP network, and manages the correspondence between node names or tag names and IP addresses.

HMI client 40 is connected to HMI server 50. Furthermore, the HMI server 50 acquires information for monitoring the field devices 20 and provides the acquired information to the HMI client 40.

Here, the distributed control system 1 is an example of a process control system. Process control systems perform real-time and non-real-time processing. Further, the tasks executed by the control node 10 include real-time processing and non-real-time processing.

Real-time processing includes execution of control applications, data transmission and reception between control nodes, and the like. For example, real-time processing is processing in which the control node 10 controls the field device 20 based on information acquired from the field device 20 (for example, PID control).

Non-real-time processing is processing related to system monitoring, field device management, quality control, advanced control, etc. For example, non-real-time processing is processing performed using data collected from a plurality of control nodes 10 over a certain period of time. In this case, the control node 10 outputs the data acquired from the field device 20 after converting the format in accordance with the subsequent processing.

Furthermore, non-real-time processing includes processing that requires a certain level of computing power and processing that requires a special device such as a GPU (Graphics Processing Unit).

In conventional DCS, real-time processing is executed by a controller (e.g., corresponding to the control node 10). Furthermore, in conventional DCS, non-real-time processing is executed by a device different from the controller, such as a PC and a server.

In contrast, the OPA (Open Process Automation) system proposed by the OPAF (Open Process Automation Forum) (References: https://www.yokogawa.com/us/solutions/featured-topics/open-process-automation) has recently been proposed by the OPAF (Open Process Automation Forum). /) and other open process control systems have been proposed. In the OPA system, the processing hierarchy is flat, and real-time processing is required even in devices other than the controller, such as a server. On the other hand, there will also be cases where non-real-time processing is executed on the control node.

A control node in an OPA system is sometimes called a DCN (Distributed Control Node). Further, the control node of this embodiment is, for example, a DCN (Distributed Control Node) in an OPA system.

The control node 10 receives regular data access while executing the tasks described above. As a result, the control node 10 may become overloaded. On the other hand, according to the management function of this embodiment, it is possible to prevent the control node 10 from becoming overloaded.

The configuration of the management server 30 will be explained using FIG. 2. FIG. 2 is a diagram illustrating a configuration example of a management server according to the first embodiment. As shown in FIG. 2, the management server 30 includes a communication section 31, a storage section 32, and a control section 33.

The communication unit 31 performs data communication with other devices. For example, the communication unit 31 is a communication interface. The communication unit 31 communicates with the control node 10 and the HMI server 50.

The storage unit 32 stores various data, various programs executed by the control unit 33, and the like. For example, the storage unit 32 is a storage device such as a memory or a hard disk. The storage unit 32 stores various data generated in the processes executed by the management server 30, such as data obtained in the process of the control unit 33 executing various processes, and processing results obtained by executing the various processes. Remember.

The storage unit 32 stores a management table 321.

The management table 321 is a table for managing the number of connections of each control node 10. The number of connections is the number of devices accessing data to the control node 10.

Here, the node IDs of the control node 10a, control node 10b, and control node 10c are assumed to be "N101," "N102," and "N103," respectively. For example, FIG. 3 shows that the number of connections of the control node 10a whose node ID is "N101" is 0.

The control unit 33 is a processing unit that controls the entire management server 30. The control unit 33 is realized by, for example, a processor. The control unit 33 includes an update unit 331, a calculation unit 332, and a notification unit 333.

The updating unit 331 updates the management table 321 when the number of connections of the control node 10 changes. A case in which the updating unit 331 updates the management table 321 will be described below.

[Case 1: System monitoring]
The update unit 331 updates the management table 321 when the HMI server 50 starts acquiring data from the control node 10 for system monitoring.

For example, as shown in FIG. 4, the HMI server 50 makes an inquiry (access inquiry) to the management server 30 in order to obtain data 110b and data 110c. FIG. 4 is a diagram showing an example of data access.

The plurality of control nodes 10 make inquiries to the management server 30 and mutually access data in response to notifications from the management server 30. Further, the HMI server 50 makes an inquiry to the management server 30 and accesses data to one of the plurality of control nodes 10 in response to a notification from the management server 30. Note that the HMI server 50 is an example of a monitoring server.

The management server 30 executes the function as a GDS, and informs the HMI server 50 that the data 110b is located in the control node 10b (node ID "N102") and the data 110c is located in the control node 10c (node ID "N103"). Notice.

After receiving the notification, the HMI server 50 periodically acquires data 110b from the control node 10b and acquires data 110c from the control node 10c.

In this case, the updating unit 331 increases the number of connections of the control node 10b (node ID "N102") and the control node 10c (node ID "N103") in the management table 321 by one.

[Case 2: Communication between control nodes for control calculation]
The update unit 331 updates the management table 321 when communication between control nodes is started for control calculation.

For example, as shown in FIG. 5, the control node 10b makes an inquiry (access inquiry) to the management server 30 in order to obtain data 110a and data 110c. FIG. 5 is a diagram showing an example of data access.

The management server 30 executes the function of a GDS, and informs the control node 10b that the data 110a is located in the control node 10a (node ID "N101") and that the data 110c is located in the control node 10c (node ID "N103"). Notice.

After receiving the notification, the control node 10b periodically acquires data 110a from the control node 10a and data 110c from the control node 10c.

In this case, the updating unit 331 increases the number of connections of the control node 10a (node ID "N101") and the control node 10c (node ID "N103") in the management table 321 by one.

The management server 30 updates the management table 321 for the control node 10 that received the access inquiry, and starts packet capturing. Thereby, the management server 30 can obtain the size of data acquired from the control node 10 through data access and the cycle at which the data is acquired.

When data access to the control node 10 is canceled, the management server 30 reduces the number of connections in the management table 321 of the control node 10 and ends packet capture.

The calculation unit 332 calculates the load of each of the plurality of control nodes 10 based on information (for example, the management table 321) indicating the status of data access to each of the plurality of control nodes 10.

The calculation unit 332 can calculate the load based on the number of data accesses to each of the plurality of control nodes 10. For example, the calculation unit 332 calculates a larger load as the number of connections recorded in the management table 321 increases.

Note that the algorithm by which the calculation unit 332 calculates the load is written in a language such as Jscript, python (registered trademark), or C language, and is realized by a program installed in advance.

Furthermore, the calculation unit 332 may calculate the load by taking into account the size of data acquired in data access and the cycle at which data is acquired. In that case, the management table 321 stores the data size to be acquired and the data acquisition cycle for each data access source (for example, the control node 10 or the HMI server 50).

Further, the calculation unit 332 may correct the calculated load based on the load of each of the plurality of control nodes 10 indicated by a known management function (such as Redfish).

For example, the calculation unit 332 calculates the average value α of the difference between the load indicated by the management function and the load calculated by the calculation unit 332. Then, the calculation unit 332 calculates a value obtained by adding α to the load calculated by the calculation unit 332 as a load correction value. Note that α may be positive or negative.

In this way, the calculation unit 332 can correct the calculated load based on the difference between the calculated load and the load indicated by the management function.

Further, for example, the calculation unit 332 calculates a ratio (ratio) β of the load indicated by the management function to the load calculated by the calculation unit 332. Then, the calculation unit 332 calculates a value obtained by multiplying the load calculated by the calculation unit 332 by β as a load correction value. Note that β may be 1 or more or less than 1.

In this way, the calculation unit 332 can correct the calculated load based on the ratio of the load indicated by the management function to the calculated load.

The calculation unit 332 may calculate α and β for each control node or for all control nodes.

The notification unit 333 provides notification when the load of any one of the plurality of control nodes 10 exceeds a threshold value. Note that different threshold values may be set for each of the plurality of control nodes 10 depending on the performance.

For example, if the load (or correction value) calculated by the calculation unit 332 exceeds a threshold, the notification unit 333 outputs an alert to the operator via the HMI server 50 or the HMI client 40.

The processing flow of the management server 30 will be explained using FIG. 6. FIG. 6 is a flowchart showing the flow of processing by the management server.

As shown in FIG. 6, the management server 30 first receives an inquiry regarding a control node from which data can be acquired (step S101). The inquiry is made by the control node 10 or the HMI server 50.

In response to the inquiry, the management server 30 notifies the control nodes from which data can be acquired (step S102). After this, data access to the control node notified that data can be obtained is started.

For example, the management server 30 uses a name resolution function to convert the data name specified by the inquiry into an IP address. For example, when the data 110b is specified, the management server 30 notifies the inquirer of the IP address of the control node 10b.

The management server 30 updates the management table 321 for the control node notified that data can be acquired (step S103). For example, the management server 30 increases the number of connected control nodes in the management table 321.

Then, the management server 30 calculates the load of each control node based on the management table 321, and determines whether the load is normal (step S104). For example, the management server 30 determines whether the calculated load exceeds a threshold value.

If the load on any of the control nodes is not normal (for example, if the load exceeds the threshold) (step S104, No), the management server 30 outputs an alert (step S105).

If the load on the control node is normal (for example, if the load does not exceed the threshold) (step S104, Yes), the management server 30 ends the process without outputting an alert.

The operator can manually make adjustments according to the load situation in response to notifications from the management server 30.

Further, the management server 30 may execute a function of automatically distributing the load of the control node 10. For example, when the load on the control node 10 exceeds a threshold, the management server 30 allocates the task of the control node 10 to another control node 10, server, or the like.

Furthermore, if the load on the control node 10 can be actually measured, the measured load may be fed back to the management server 30. In that case, the management server 30 can receive feedback and optimize the algorithm for calculating the load. For example, the management server 30 holds constants similar to α and β described above regardless of the management function, and corrects the constants in accordance with feedback.

[effect]
As described above, the management server 30 includes a calculation section 332 and a notification section 333. The calculation unit 332 calculates the load of each of the plurality of control nodes 10 based on information indicating the status of data access to each of the plurality of control nodes 10. The notification unit 333 provides notification when the load of any one of the plurality of control nodes 10 exceeds a threshold value.

For example, the calculation unit 332 calculates the load based on the number of data accesses to each of the plurality of control nodes 10.

The operator can take action to reduce the load in response to the notification. In this manner, the management server 30 can prevent the control nodes of the DCS (distributed control system 1) from becoming overloaded.

Furthermore, if the load on the control node 10 is less than the allowable amount (for example, about 90% of the allowable amount), the control node 10 can accurately communicate its own load to the outside. On the other hand, if the load on the control node 10 exceeds the allowable amount (for example, about 120% of the allowable amount), it may become difficult for the control node 10 to accurately communicate its own load to the outside. Even in such a case, the management server 30 can calculate the load on the control node 10.

The management server 30 can calculate the load without acquiring any information from the control node 10 itself. Therefore, the management server 30 can calculate the load regardless of the vendor and specification of the control node 10.

Further, the calculation unit 332 corrects the calculated load based on the load of each of the plurality of control nodes 10 indicated by the management function. For example, the calculation unit 332 corrects the calculated load based on the difference between the calculated load and the load indicated by the management function. For example, the calculation unit 332 corrects the calculated load based on the ratio of the load indicated by the management function to the calculated load. The notification unit 333 provides notification when the corrected load exceeds the threshold value. Thereby, the management server 30 can improve the accuracy of load calculation.

[system]
Information including processing procedures, control procedures, specific names, and various data and parameters shown in the above documents and drawings can be changed arbitrarily unless otherwise specified.

Furthermore, each component of each device shown in the drawings is functionally conceptual, and does not necessarily need to be physically configured as shown in the drawings. That is, the specific form of distributing and integrating each device is not limited to what is shown in the drawings. In other words, all or part of them can be functionally or physically distributed and integrated into arbitrary units depending on various loads, usage conditions, and the like.

Furthermore, all or any part of each processing function performed by each device can be realized by a CPU and a program that is analyzed and executed by the CPU, or can be realized as hardware using wired logic.

[hardware]
Next, an example of the hardware configuration of the management server 30 will be described. FIG. 7 is a diagram illustrating an example of a hardware configuration. As shown in FIG. 7, the management server 30 includes a communication device 300a, an HDD (Hard Disk Drive) 300b, a memory 300c, and a processor 300d. Furthermore, the parts shown in FIG. 7 are interconnected by a bus or the like.

The communication device 300a is a network interface card or the like, and communicates with other devices. The HDD 300b stores a program and DB that operate the functions shown in FIG.

The processor 300d reads a program that executes the same processing as each processing unit shown in FIG. 2 from the HDD 300b, etc., and deploys it in the memory 300c, thereby operating a process that executes each function described in FIG. 2, etc. For example, this process executes the same functions as each processing unit included in the management server 30. Specifically, the processor 300d reads a program having the same functions as the update section 331, the calculation section 332, and the notification section 333 from the HDD 300b or the like. Then, the processor 300d executes a process that performs the same processing as the update unit 331, the calculation unit 332, and the notification unit 333.

In this way, the management server 30 operates as an information processing device that executes an information processing method by reading and executing a program. Furthermore, the management server 30 can also realize the same functions as in the above-described embodiments by reading the program from a recording medium using a medium reading device and executing the read program. Note that the programs in other embodiments are not limited to being executed by the management server 30. For example, the present invention can be similarly applied to cases where another computer or server executes a program, or where these computers or servers cooperate to execute a program.

This program can be distributed via a network such as the Internet. Additionally, this program is recorded on a computer-readable recording medium such as a hard disk, flexible disk (FD), CD-ROM, MO (Magneto-Optical disk), or DVD (Digital Versatile Disc), and is read from the recording medium by the computer. It can be executed by being read.

Some examples of combinations of disclosed technical features are described below.

(1)
a calculation unit that calculates the load of each of the plurality of control nodes based on information indicating the status of data access to each of the plurality of control nodes;
a notification unit that issues a notification when the load of any one of the plurality of control nodes exceeds a threshold;
An information processing device comprising:
(2)
The information processing device according to (1), wherein the calculation unit calculates the load based on the number of data accesses to each of the plurality of control nodes.
(3)
The calculation unit corrects the calculated load based on the load of each of the plurality of control nodes indicated by the management function, and the notification unit sends a notification when the corrected load exceeds the threshold. The information processing device according to (1) or (2).
(4)
The calculation unit corrects the calculated load based on the difference between the calculated load and the load indicated by the management function, and the notification unit corrects the calculated load when the corrected load exceeds the threshold value. , the information processing device according to any one of (1) to (3).
(5)
The calculation unit corrects the calculated load based on the ratio of the load indicated by the management function to the calculated load, and the notification unit sends a notification when the corrected load exceeds the threshold. The information processing device according to any one of (1) to (3), characterized in that the information processing device performs the following.
(6)
A management server that notifies data access destinations in response to inquiries, multiple control nodes, a monitoring server,
A distributed control system having
The plurality of control nodes are
making an inquiry to the management server and mutually accessing data in response to a notification from the management server;
The monitoring server is
A distributed control system characterized by performing processing equivalent to the information processing device according to any one of (1) to (5).

1 Distributed control system 10, 10a, 10b, 10c Control node 20, 21a, 22a Field device 30 Management server 31 Communication unit 32 Storage unit 33 Control unit 40 HMI client 50 HMI server 110a, 110b, 110c Data 321 Management table 331 Update unit 332 Calculation section 333 Notification section

Claims (5)

The load of each of the plurality of control nodes is calculated based on information indicating the status of data access to each of the plurality of control nodes, and the calculated load and the load of each of the plurality of control nodes indicated by the management function are calculated. and a calculation unit that corrects the calculated load based on the difference between the calculated load or the ratio of the load of each of the plurality of control nodes indicated by the management function to the calculated load;
a notification unit that outputs an alert to an HMI device when the load corrected by the calculation unit of any of the plurality of control nodes exceeds a threshold;
An information processing device comprising: The information processing apparatus according to claim 1, wherein the calculation unit calculates the load based on the number of data accesses to each of the plurality of control nodes. The load of each of the plurality of control nodes is calculated based on information indicating the status of data access to each of the plurality of control nodes, and the calculated load and the load of each of the plurality of control nodes indicated by the management function are calculated. or based on the ratio of the load of each of the plurality of control nodes indicated by the management function to the calculated load, and
An information processing method characterized in that a computer executes a process of: outputting an alert to an HMI device when the corrected load of any of the plurality of control nodes exceeds a threshold value. The load of each of the plurality of control nodes is calculated based on information indicating the status of data access to each of the plurality of control nodes, and the calculated load and the load of each of the plurality of control nodes indicated by the management function are calculated. or based on the ratio of the load of each of the plurality of control nodes indicated by the management function to the calculated load, and
Information processing characterized by causing a server connected to the plurality of control nodes to execute a process of outputting an alert to an HMI device when the corrected load of any one of the plurality of control nodes exceeds a threshold value. program. A management server that notifies data access destinations in response to inquiries, multiple control nodes, a monitoring server,
A distributed control system having
The plurality of control nodes are
making an inquiry to the management server and mutually accessing data in response to a notification from the management server;
The monitoring server is
making an inquiry to the management server and accessing data to one of the plurality of control nodes in response to a notification from the management server;
The management server is
The load of each of the plurality of control nodes is calculated based on information indicating the status of data access to each of the plurality of control nodes, and the calculated load and the load of each of the plurality of control nodes indicated by the management function are calculated. and a calculation unit that corrects the calculated load based on the difference between the calculated load or the ratio of the load of each of the plurality of control nodes indicated by the management function to the calculated load;
a notification unit that outputs an alert to the monitoring server when the load corrected by the calculation unit of any of the plurality of control nodes exceeds a threshold;
A distributed control system comprising:

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