JP2007334724A - Process with message bus and control system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve problems that each application is executed in different process, so that distribution of resources to each process and its verification become difficult, to impair real-time property. <P>SOLUTION: A component having predetermined functions, a name service component, and a communication component perform communication through a message bus, and the communication to the outside is performed through the communication component. These components are applicable to a control system. Since the interface between the components and the message bus are simplified, the performance is increased, a real-time property is secured, and an existing package can be used by preparing a wrapper. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a process capable of performing efficient processing without impairing real-time performance, and a control system using this process.

  In the control system, not only the original control operation but also many functional blocks for performing data collection, data analysis, device management and the like are executed in parallel. Each of these functional blocks is constructed as a single application. When cooperation between applications is necessary, communication between applications is performed, and processing is performed while exchanging information with each other.

  FIG. 5 shows a schematic diagram of such a control system. In FIG. 5, reference numerals 11 to 15 denote applications, which operate as functional blocks. For example, the application 11 executes a control operation, the application 12 performs data collection, and the application 13 performs data analysis. Each application is operating as a separate process.

In order to achieve a given purpose, each application must work together. Therefore, communication is performed between the applications 11 to 15 to exchange information and to operate in cooperation.
Japanese Patent Laid-Open No. 2001-125872

  However, in order to execute each application as a separate process, resources must be allocated to these applications. However, when the number of applications increases, it becomes difficult to allocate sufficient resources to each application, and as a result, there is a problem that it is difficult to sufficiently extract the performance of the application.

  In addition, it is necessary to verify the operation when the applications are combined. However, when the number of applications increases, the number of combinations becomes enormous, and there is a problem that it is difficult to verify all of them.

  In addition, since there is no unified system construction method, it is difficult to use libraries and reuse modules, resulting in a reduction in development efficiency.

  In addition, since communication between applications must be specified for each application, it is difficult to unify communication methods, and there is a problem that the real-time property required for the control system is impaired due to an increase in communication load. .

  Furthermore, since the control system is divided into a plurality of processes, the management of transactions and logs becomes complicated, and the system management becomes difficult.

  Accordingly, an object of the present invention is to provide a process having a message bus that does not impair the real-time property by constructing a functional block as a component and connecting the components by a message bus as one process, and this process It is to provide a control system using the.

In order to achieve such a problem, the invention according to claim 1 of the present invention is:
A message bus that conveys a message with destination information and destination information attached;
A component having a predetermined function and exchanging information via the message bus;
Information of the component is registered, and a name service component that transmits the registered information to the inquiry source via the message bus in response to an inquiry;
A communication component that exchanges information with the component via the message bus and mediates communication with the outside;
Is provided. Real-time performance can be secured.

The invention according to claim 2 is the invention according to claim 1,
The message is an asynchronous message. Communication performance is improved.

The invention according to claim 3 is the invention according to claim 1,
The message is a synchronous message, and the component that has received the synchronous message transmits a reply message, and the component that has transmitted the synchronous message suspends processing until the reply message is received. Because the other party can confirm that it has been received, it can communicate reliably.

The invention according to claim 4 is the invention according to any one of claims 1 to 3,
It uses a wrapper that resides as part of the system and centrally manages services over the network, and incorporates existing packages. Existing packages can be used.

The invention according to claim 5 is the invention according to any one of claims 1 to 4,
The communication component communicates with the outside using SOAP (Simple Object Access Protocol). Web services can be used.

The invention according to claim 6 is the invention according to any one of claims 1 to 5,
The message bus manages transaction processing and / or log processing. These processes can be easily performed.

The invention according to claim 7 is the invention according to any one of claims 1 to 6,
A plurality of communication components are provided. It can support multiple communication methods.

The invention described in claim 8
At least one of the processes is built in the control system. It is suitable for use in control systems where real-time performance is important.

As is apparent from the above description, the present invention has the following effects.
According to the first, second, third, fourth, fifth, sixth and seventh aspects, the component having a predetermined function, the name service component, and the communication component communicate via the message bus, and communication to the outside is performed. It was done via the communication component. It was also applied to the control system.

  Since the interface between the component and the message bus is simplified, there is an effect that performance is improved and real-time performance can be secured. Further, by creating a wrapper, there is an effect that an existing library or application can be easily connected to the message bus.

  In addition, the interface between the component and the message bus can be simplified, and the interface function with the message bus, the log function, and the like can be shared, so that the development efficiency can be improved. In addition, since the components have the same interface, there is an effect that management such as resource allocation to the components, grasping of the situation, and dynamic addition / deletion of components is simplified.

  Further, since all communication between components passes through the message bus, there is an effect that transaction processing and log processing can be easily performed.

  Hereinafter, the present invention will be described in detail with reference to the drawings. FIG. 1 is a block diagram showing an embodiment of a process having a message bus according to the present invention. In FIG. 1, reference numeral 20 denotes a process, which includes components 21 to 24, a name service component 25, a communication component 26, and a message bus 27. Each of the components 21 to 24, the name service component 25, and the communication component 26 has an interface for connecting to the message bus 27.

  A process 30 includes components 31 to 34, a name service component 35, a communication component 36, and a message bus 37. The components 31 to 34, the name service component 35, and the communication component 36 each have an interface for connecting to the message bus 37.

  A communication bus 40 is connected to the communication components 26 and 36. Processes 20 and 30 exchange information via this communication bus 40. Also, information is exchanged with other systems and applications (not shown) via the communication bus 40. In this embodiment, the two processes 20 and 30 are connected by the communication bus 40, but three or more processes may be connected. Further, the number of components incorporated in each process can be arbitrarily selected.

  The components 21 to 24 are software modules for realizing a predetermined function. Although the function which these components 21-24 implement | achieve can be selected arbitrarily, the function which each component implement | achieves is separated so that the dependence between components may be reduced as much as possible.

  The components 21 to 24, the name service component 25, and the communication component 26 exchange messages via the message bus 27. These components exchange all information via messages 27. The message bus 27 exchanges information to be transferred in a DTO (Data Transfer Object). Therefore, unlike an ORB (Object Request Broker) that exchanges data between objects distributed on different machines, the interface is simple and single. The message bus 27 is a software bus and does not necessarily have a hardware communication path.

  The message flowing on the message bus 27 includes a synchronous message and an asynchronous message. In addition, a sender and a destination are added to the content to be transmitted, and a setting for distinguishing between a synchronous message / asynchronous message / synchronous message reply is made. The content may be described in XML (eXtensible Markup Language), but may be binary data.

  The name service component 25 is a component for performing component name resolution. When a component exchanges information with other components in the same process, it needs to know information about the counterpart component, but it is the component that provides this information.

  The communication component 26 is a component for communicating with other processes. When the components 21 to 24 need to exchange information with other processes, the communication is performed through the communication component. Therefore, even if the components 21 to 24 do not include a communication module corresponding to the outside of the process 20, the components 21 to 24 can communicate with components of other processes only by changing the destination.

  A plurality of communication components 26 can be used. By making these plural communication components correspond to protocols such as SOAP (Simple Object Access Protocol) and COBRA (Common Object Request Broker Architecture), various communications can be supported.

  The process 30 has the same configuration as the process 20 although the functions realized by the components 31 to 34 are different. That is, the components 31 to 34, the name service component 35, and the communication component 36 exchange information via the message bus 37 using DTO, and the name service component 35 performs name resolution. Further, when it becomes necessary to exchange information with another process, it is performed via the communication component 36.

  Since message buses 27 and 37 do not communicate during information exchange, no delays due to communication delays or network failures occur. In addition, since the real-time property of each component can be directly converted into the real-time property of the process, the real-time property of the process can be kept high.

  Further, since all inter-component communication passes through the message bus, transaction processing and log processing can be managed by the message bus.

  FIG. 2 shows a procedure for connecting components to the message bus. Although the process 20 will be described, the process 30 is the same. In FIG. 2, a component to be connected to the name service component 25 is registered in step (P2-1). After completion of the registration process, a message bus 27 reference is received from the name service component 25 in step (P2-2). In step (P2-3), the message handler of the component to be connected is registered with respect to the message bus 27 reference. Thus, the component can distribute the message using the message bus 27.

  Components can be connected dynamically not only at process startup but also during execution. In addition, when an existing library or application is connected to the message bus 27, a wrapper is used. The wrapper is software that resides as part of the system and centrally manages services over the network. Since there is a single interface to the message bus 27, it is easy to create a wrapper.

  FIG. 3 shows a procedure for disconnecting components from the message bus. Although the process 20 will be described, the process 30 is the same. In FIG. 3, in the step (P3-1), the registration of the name service component 25 is deleted for the component to be deleted. In step (P3-2), the registration to the message bus 27 is deleted for the same component.

  Next, in step (P3-3), if there is a message addressed to the deleted component among the messages that have not been distributed, it is deleted and an error message is transmitted to the transmission source. In step (P3-4), a component waiting for a reply from the deleted component is searched for, and an error message is transmitted to this component. This ensures that the component is safely disconnected from the message bus 27.

  FIG. 4 shows a procedure for exchanging messages between components. Although the process 20 will be described, the process 30 is the same. In FIG. 4, in the step (P4-1), the component to be transmitted acquires the destination information of the component to be transmitted from the name service component. In step (P4-2), a message is created, and the acquired destination information is set as the destination of this message, and its own destination information is set as the source.

  Next, message content (main body part) is created in step (P4-3), and the message created in step (P4-4) is transmitted to the message bus 27. The message bus 27 refers to the destination of the message in step (P4-5) and delivers this message to the message handler of the destination component.

  Messages can be exchanged either synchronously or asynchronously. In the synchronous type, when the transmission source component sends a message to the message bus 27, processing of the transmission source component is performed until a reply message arrives. Is blocked. When the destination component creates a reply message and sends it to the message bus 27 and the message bus 27 delivers the reply message to the source component, the blocked processing is resumed.

  In the control system, there are individual databases for storing control data and packages for performing analysis. Normally, these databases and packages operate as separate processes, but these databases and packages can be incorporated into the same process by componentizing them. Also, by using a wrapper, an existing package can be taken into the process. Therefore, it is possible to sufficiently draw out performance and secure real-time performance.

  In recent control systems, connection with MES (Manufacturing Execution System) and ERP (Enterprise Resource Planning) is increasing. Web services are often used for these exchanges with MES and ERP. By making the communication component compatible with SOAP, each component can be easily connected to these systems without making it compatible with SOAP. Since the interface of the message bus conforms to the definition of the Web service, WSDL (Web Services Description Language) can be automatically generated.

It is a block diagram which shows one Example of this invention. It is a flowchart which shows the procedure which connects a component to a message bus. It is a flowchart which shows the procedure which isolate | separates a component from a message bus. It is a flowchart which shows the communication procedure between components. It is a schematic diagram of the conventional control system.

Explanation of symbols

20, 30 Processes 21-24, 31-34 Component 25, 35 Name service component 26, 36 Communication component 27, 37 Message bus 40 Communication bus

Claims (8)

A message bus that conveys a message with destination information and destination information attached;
A component having a predetermined function and exchanging information via the message bus;
Information of the component is registered, and a name service component that transmits the registered information to the inquiry source via the message bus in response to an inquiry;
A communication component that exchanges information with the component via the message bus and mediates communication with the outside;
A process having a message bus.   The process having a message bus according to claim 1, wherein the message is an asynchronous message.   The message is a synchronous message, and a component that has received the synchronous message transmits a reply message, and the component that has transmitted the synchronous message suspends processing until the reply message is received. A process having a message bus according to Item 1.   The message bus according to any one of claims 1 to 3, wherein an existing package is fetched by using a wrapper that is resident as a part of the system and centrally manages services through a network. process.   5. The process having a message bus according to claim 1, wherein the communication component communicates with the outside using SOAP (Simple Object Access Protocol).   6. The process having a message bus according to claim 1, wherein the message bus manages transaction processing and / or log processing.   The process having a message bus according to any one of claims 1 to 6, comprising a plurality of the communication components. A control system comprising at least one of the processes.

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