JP2004102586A - Autonomous distributed system and communicating method thereof - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an autonomous distributed system eliminated in necessity of considering communication data between control devices in a planning stage and capable of changing scramble data of the communication between the control devices without stopping operation. <P>SOLUTION: This autonomous distributed system is provided with a plurality of control devices A, B and C connected to a network 10. Each of the plurality of control devices A, B and C is provided with an inquiry unit for inquiring other control devices A, B and C through group cast communication when an output element, which has the same discriminator with a discriminator previously assigned by a planing tool in relation to an input element, does not exist in a self-control device and an acquisition unit for acquiring an output element from other control devices A, B and C in response to an inquiry by the inquiry unit. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a distributed autonomous system and a communication method thereof, and more particularly to a technique for transferring data between a plurality of control devices.
[0002]
[Prior art]
BACKGROUND ART Conventionally, a distributed system including a plurality of control devices is known. In this distributed system, it is necessary for a plurality of control devices to share data. Therefore, it is required that a plurality of control devices exchange data with each other and constantly update the data with the latest data.
[0003]
Conventionally, in order to satisfy such requirements, it is necessary to design a system configuration in advance in order to perform communication between control devices. Further, data exchanged in communication between the control devices is handled in a fixed manner, and when the exchange data is changed, it is necessary to stop all the control devices and change the settings.
[0004]
As a related technique, since a change in the program of a continuously operating control device often involves a change in the data portion, it is possible to cope with a change in the data and to execute a program that can be safely changed. Is known (for example, see Patent Document 1). In this method of changing the program during operation, both the program before and after the change are stored in the memory, and the variables constituting the change before and after the change are determined as to whether or not there is a change, and whether or not a new addition is to be made. The operation result is copied for the variable, the initialization operation is performed for the changed or newly added variable, and switching is performed while executing the control.
[0005]
[Patent Document 1]
JP-A-2002-63045
[Problems to be solved by the invention]
Therefore, an object of the present invention is to provide an autonomous decentralized system and a communication method thereof that can change communication data for communication between control devices without having to consider communication data between control devices at the design stage and without stopping operation. Is to provide.
[0007]
[Means for Solving the Problems]
The means for solving the problem will be described below using the numbers and symbols used in [Embodiments of the Invention]. These numbers and symbols are added to clarify the correspondence between the description of [Claims] and the description of [Embodiments of the Invention]. It should not be used to interpret the technical scope of the described invention.
[0008]
In order to achieve the above object, a distributed autonomous system according to a first aspect of the present invention is a distributed autonomous system including a plurality of control devices (A, B, C) connected by a network (10). In each of the plurality of control devices (A, B, C), there is no output element having the same identifier as the identifier previously assigned to the input element by the design tool (20) in its own control device. In this case, an inquiry unit for inquiring other control devices (A, B, C) by groupcast communication, and an acquiring unit for acquiring output elements from the other control devices (A, B, C) by inquiry by the inquiry unit It has.
[0009]
According to the autonomous decentralized system according to the first aspect, it is not necessary to consider communication data between control devices at the design stage. Further, it is possible to change the data for communication between the control devices without stopping the distributed autonomous system.
[0010]
In the distributed autonomous system according to the first aspect, the inquiry unit can be configured to periodically inquire other control devices (A, B, C). According to this configuration, when a new control device enters the network (10), an unsolved input element having no output element with respect to the input element may be solved (data from the corresponding output element). Is obtained.
[0011]
Further, in the distributed autonomous system according to the first aspect, the response to the inquiry by the inquiry unit can be configured to be performed by a server / client communication system. By employing this communication method, the conventional hardware and software resources can be used in a mixed manner.
[0012]
A communication method for a distributed autonomous system according to a second aspect of the present invention is a communication method for a distributed autonomous system including a plurality of control devices (A, B, and C) connected by a network (10). , Each of the plurality of control devices (A, B, C) performs a group cast when an output element having the same identifier as an identifier previously assigned to the input element by the design tool does not exist in its own control device. It is configured to make an inquiry to another control device (A, B, C) by communication, and acquire an output element from the other control device (A, B, C) by inquiry.
[0013]
In the communication method of the autonomous decentralized system according to the second aspect, the inquiry can be made periodically. In addition, a response to the inquiry can be configured to be performed by a server / client communication method. The communication method of the autonomous decentralized system according to the second aspect has the same operation and effect as the autonomous decentralized system according to the first aspect described above.
[0014]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
[0015]
FIG. 1 is a block diagram showing a configuration of a decentralized autonomous system according to an embodiment of the present invention. The autonomous decentralized inter-system communication device includes a plurality of control devices A, B, and C connected to a network 10 and a design tool 20. A database 21 is connected to the design tool 20.
[0016]
The control devices A, B, and C include an input element that represents capturing data and an output element that represents generating and writing data. Here, the output element is an element that holds data, and the input element can be considered as an element that refers to the output element.
[0017]
The input element and the output element are given global identifiers commonly used by the control devices A, B, and C. As described above, by making the identifier a global identifier, the number of identifiers (variables) used in the entire autonomous distributed system can be reduced, and the memory area of each control device can be saved. In FIG. 1, the differences between the identifiers are schematically represented by figures such as circles, squares, and triangles. In FIG. 1, a graphic connected to the end point of the arrow represents an output element, and a graphic connected to the start point of the arrow represents an input element.
[0018]
The control device A has an input / output element management table 30. In the input / output element management table 30, input elements and output elements are classified and stored. The control devices B and C also have similar input / output element management tables, but are not shown.
[0019]
The design tool 20 performs a process of assigning unique identifiers to input elements and output elements newly generated when data is changed. Since the global identifier is managed in the database 21 so as not to be duplicated, the design tool 20 assigns a global identifier to a new input element or output element by referring to the database 21. .
[0020]
Next, the operation of the distributed autonomous system according to the embodiment of the present invention configured as described above will be described. Hereinafter, the operation of the control device A will be mainly described, but the operations of the controls B and C are the same as the operations of the control device A.
[0021]
First, when the autonomous distributed system is started and when data in the control device A constituting the autonomous distributed system is changed online, the input elements and output elements included in the control device A are stored in the input / output element management table 30. Classified and expanded. At this time, an input element having no corresponding output element is extracted and registered in the unresolved list.
[0022]
In the example shown in FIG. 1, the input element 31 is not registered in the unsolved list because the input element 31 is completed by the presence of the output element 32 having the same identifier. On the other hand, the input element 33 is registered in the unsolved list because there is no output element having the same identifier in the control device A.
[0023]
Next, the control device A inquires of the other control devices B and C via the network 10 about the input element 33 registered in the unsolved list. This inquiry is performed by, for example, group cast communication (IP multicast communication) in which an unspecified number of other parties are inquired and a response is obtained.
[0024]
In response to the inquiry, a control device including an output element having the same identifier as the input element 33 related to the inquiry responds. In the example shown in FIG. 1, the control device B having the output element 41 responds, and the control device C does not respond. The control device B returns the output element 41 to the control device A by the server / client communication method. In this case, the control device B works as a server.
[0025]
The control device A receives the output element 41 and registers it in the input / output element management table 30. As a result, the unsolved input element 33 is resolved.
[0026]
Apart from the above series of operations, in case that the input is not resolved, in other words, when the output element corresponding to the input element cannot be obtained from another control device, and when a new control device is connected to the network 10, Thus, the control device A periodically makes an inquiry to another control device.
[0027]
For example, after the controller C is removed from the distributed autonomous system due to a failure or the like, the controller C cannot respond to the inquiry. If nothing is done, the control device C keeps determining that it cannot respond. As described above, such a problem is solved by the configuration in which the control device A periodically makes an inquiry to another control device.
[0028]
As described above, according to the autonomous decentralized system according to the embodiment of the present invention, when the input element is unresolved, the output element is obtained from another control apparatus. It is not necessary to consider communication data. Further, it is possible to change the data for communication between the control devices without stopping the operation of the autonomous distributed system.
[0029]
【The invention's effect】
As described above in detail, according to the present invention, there is no need to consider communication data between control devices at the design stage, and an autonomous distributed system that can change data for communication between control devices without stopping operation And a communication method thereof.
[Brief description of the drawings]
FIG. 1 is a block diagram illustrating a configuration of a decentralized autonomous system according to an embodiment of the present invention.
[Explanation of symbols]
Reference Signs List 10 network 20 design tool 21 database 30 input / output element management tables 31, 33, 42 input elements 32, 41, 51 output elements

Claims (6)

An autonomous decentralized system including a plurality of control devices connected by a network,
Each of the plurality of control devices includes:
When an output element having the same identifier as the identifier previously assigned by the design tool for the input element does not exist in its own control device, an inquiry unit that inquires another control device by group cast communication,
An acquisition unit that acquires the output element from the other control device by an inquiry by the inquiry unit;
And an autonomous decentralized system with The autonomous decentralized system according to claim 1, wherein the inquiry unit periodically inquires the other control device. The autonomous decentralized system according to claim 2, wherein a response to the inquiry by the inquiry unit is performed by a server / client communication system. A communication method of an autonomous decentralized system including a plurality of control devices connected by a network,
Each of the plurality of control devices includes:
When there is no output element having the same identifier as the identifier previously assigned by the design tool for the input element in its own control device, an inquiry is made to another control device by group cast communication,
Acquiring the output element from the other control device by the inquiry,
Communication method for autonomous distributed system. The communication method for an autonomous distributed system according to claim 4, wherein the inquiry is performed periodically. The communication method for an autonomous distributed system according to claim 5, wherein the response to the inquiry is performed by a server / client communication system.

Images