JPS63216102A - Plant control system - Google Patents

Abstract

PURPOSE:To facilitate the coordination and assistance among plural control systems by adding a function for the communication in a control system and controlling the execution by the IF-THEN type rules. CONSTITUTION:A memory 7 for the communication between the control systems 2 is provided and the communication between the control systems 2 is described by the communication rule of a form referencing the memory 7 for the communication, the conventional control rule and the deduction by the communication rule are processed in pseudo-parallel way and the execution interruption/restart of the control rule is controlled by the communication rule. The memory 7 for the communication stores a message from other control system and the communication rule of a form referencing said memory controls the information exchange between the control systems 2 and the synchronization of the control operation. Thus, the coordination and assistance device between the control systems 2 are easily realized.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention is directed to a plant that realizes automation of manual operation areas and plant diagnostic functions in order to improve plant reliability and reduce the burden on operators. It concerns control systems.

[Conventional technology]

FIG. 3 is a block diagram showing a conventional plant control system disclosed in, for example, Japanese Unexamined Patent Publication No. 59-163605. In FIG. 1, 1 is a plant to be controlled, and 2 is a control system. Also.

3 is a process quantity signal indicating the state quantity of the plant 1 sent from the plant 1 to the control system 2; 4 is an input/output signal processing device; 5 is a binary logic signal binarized by the input/output signal processing device 4; 6 is an inference processing unit that performs inference processing on this binary logic signal 5; 7 is a working memory that serves as a work area for the inference processing of the inference processing unit 6; and 8 is an if-then used in the inference processing of the inference processing unit 6. (IF-THE N) type rule is stored in a rule base, 9 is a binary logic signal indicating the inference result of the inference processing unit 6, which is sent to the input/output signal processing device F14, and 10 is the input/output signal processing device. 4 is an operation command signal sent to the plant 1, and the control system 2 is constituted by these.

Next, the operation will be explained. The control system 2 takes in the process quantity signal 3 of the plant 1, converts it into a binary logic signal 5 using the input/output signal processing device 4, and sends it to the inference processing section 6. The contents of the working memory 7 are updated based on this binary logic signal 5, and the contents of the working memory 7 indicate the current state of the plant 1. The inference processing unit 6 uses the contents of the working memory 7 and the I stored in the rule base 8.
The condition parts of the F-THEN type rules are compared, and the contents of the conclusion part of the matching rule are written into the working memory 7. Furthermore, the result is output as a binary logic signal 9,
Operation command signal 10 to the plant by input/output signal processing device
and is input to the operating end of the plant 1. This makes it possible to implement control operations based on control logic written in IF-THEN rules.

[Problem that the invention seeks to solve]

Conventional plant control systems are configured as described above, so they do not have information exchange functions between control systems, and even if they do, they are weak, making coordination and cooperation between control systems easy. However, there was a problem in that it was difficult to realize the advanced autonomous distributed control system that would be essential for future large-scale plants.

This invention was made to solve the above-mentioned problems, and aims to provide a plant control system that can exchange advanced information between control systems and realize coordination and cooperation functions between control systems. purpose.

[Means for solving problems]

The plant control system according to the present invention includes a memory for communication between the control systems, and describes the communication between the control systems using a communication rule that refers to the memory for communication, thereby allowing normal control. The communication rules and the inferences based on the communication rules are processed in pseudo-parallel manner, and further,
It is possible to control the suspension and resumption of execution of control rules from the communication rules.

[Effect]

The memory for communication in this invention stores messages from other control systems, and controls information exchange between control systems and synchronization of control operations using communication rules that refer to this memory. Easily implement mechanisms for coordination and cooperation between systems.

〔Example〕

An embodiment of the present invention will be described below with reference to the drawings.

In Fig. 1, 1 is a plant, 2 is a control system, and 3 is a plant.
is a process amount signal, 4 is an input/output signal processing device, 5 is a binary logic signal, 6 is an inference processing unit, 7 is a working memory, 8
is a rule base, 9 is a binary logic signal indicating the inference result, 1
0 is an operation command signal, which is the same as, or corresponds to, those in the prior art denoted by the same reference numerals in FIG. 3, so a detailed explanation will be omitted. Further, 11 is a plant database provided in the working memory 7 for storing the state of the plant 1 and intermediate hypotheses in reasoning, and 12 is a plant database for storing messages communicated with other control systems 2. A communication message storage area is also provided in the working memory 7 for storing communication messages, and 13 is a network for communicating between a plurality of control systems 2;
4 is a network provided within the control system 2 for sending and receiving messages via this network 13;
- Quintaface. In addition, the rule base 8
The plant database 11 of the working memory 7
A normal control rule group consisting of IF-THEN type control rules that refer to , and a communication rule group consisting of IF-THEN type communication rules that refer to the communication message storage area 12 of the working memory 7. Stored.

Next, the operation of the above embodiment will be explained with reference to the drawings.

FIG. 2 is a general flowchart showing the processing flow of the entire system. The system comes first.

As step STI, the process amount signal 3 of the plant 1 is taken in via the input/output signal processing device 4 shown in FIG. 1, and the plant database 11 in the working memory 7 is rewritten according to its state. Next, in step ST2, the rules stored in the rule base 8 are compared with the contents of the plant database 11 in the working memory 7, and in step ST3
A rule to be executed is selected from among the rules established in step ST4, and the conclusion part of the rule is executed in step ST4.

In the execution of the conclusion part, the working memory 7 is rewritten, control commands are output, and other rule groups are started (switching the rule group of interest), etc. Next, in step ST5, the termination condition for applying the rule group is determined and the process branches. If the process does not end, the process moves to execution of the communication rule group. Step ST6
Then, the condition part of the communication rule is verified, and step ST
The 0 communication rule, which selects a rule to be executed in step ST8 and executes its conclusion part in step ST8, selects the received message (sent from another control system 2) stored in the communication message storage area 12 provided in the working memory 7. The control system 2 processes the received message) and the transmitted message (message to be sent to another control system 2). That is, the communication message storage area 12 in the working memory 7 cannot be accessed from the normal control rules, and the communication rules distribute the received messages to the plant data beta 11 that can be accessed from the normal control rules. write to. The steps up to this point constitute one cycle of execution of this system.

These steps are repeated until the termination condition is satisfied. In addition, in the execution of the conclusion part of the communication rule in step ST8, other rules can be started as necessary, and at this level, it is possible to control the suspension and restart of the execution of the control rule side. This allows for flexible cooperative control.

In the above embodiment, the network 1 connecting the control system u■
Although the hardware and method of No. 3 were not specifically described, it is sufficient to create the network interface 14 in accordance with a specific standard, and this has nothing to do with the essence of the present invention. Further, in the above embodiment, a microprocessor-based controller is assumed as the hardware for realizing the control system, but a process control computer such as a minicomputer may also be used, and the same effects as in the above embodiment can be obtained.

〔Effect of the invention〕

As described above, according to the present invention, a communication function is added within the control system, and its execution is configured to be controlled by IF-THEN type rules, so that coordination between multiple control systems is possible. This has the effect of making it possible to easily realize cooperation and cooperation, making it possible to construct advanced autonomous distributed control systems that are indispensable in large-scale plants.

[Brief explanation of the drawing]

FIG. 1 is a system configuration diagram showing a plant control system according to an embodiment of the present invention, FIG. 2 is a general flowchart showing the process flow thereof, and FIG. 3 is a system configuration diagram showing a conventional plant control system. 1 is a plant, 2 is a control system, 6 is an inference processing unit, 8
1 is a rule base, 11 is a plant database, and 12 is a memory for communication (communication message storage area). In addition, in the figures, the same reference numerals indicate the same or equivalent parts.

Claims (1)

[Claims] A plant database that manages the state of the plant online, a rule base that stores a group of control rules made up of control rules that refer to this plant database, and the contents of the plant database and the rules of the rule base. In a plant control system equipped with an inference processing unit that performs inference based on rules according to a rule execution format specified by a group, a memory for communication between the control systems is provided, and a memory for this communication is provided. A communication rule group composed of communication rules in a reference format is stored in the rule base, and inferences based on the control rule group and the communication rule group are processed in pseudo-parallel, and the communication rules are A plant control system characterized by controlling suspension and resumption of execution of the control rule group.