JPH02263202A - Plant controller - Google Patents

Abstract

PURPOSE:To main the optimum plant control for a long period of time by using an identification means to identify a plant based on the inputted information on the identification and to design a plant model and therefore grasping surely the process fluctuations due to various of factors of the plant for simple update of the plant model. CONSTITUTION:An identification means 41 identifies a plant based on the inputted information on the identification and designs a plant model. A monitor means 44 monitors whether or not a significant difference is produced between the plant model designed by the means 41 and an actual plant model. Then a model updating means 46 updates the actual plant model to the designed one when the means 44 decides the presence of the significant difference between both models. Thus a newly designed plant model can be updated and the control is carried out based on the updated plant model. As a result, the plant model can be changed in accordance with the fluctuation of the process characteristics. Then the optimum control is always secured based on the plant model.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Application Field) The present invention relates to a plant control device that requires a plant model in, for example, a paper pulp manufacturing process or an oil refining process.

(Prior art) Conventionally, when using a plant model in plant control, a plant model is designed by analyzing process characteristics (dynamic characteristics, static characteristics) data such as step responses collected in advance, and control is performed based on this plant model. It is common to create a device and start plant control.

However, in the plant to be controlled, changes occur compared to when the plant model was designed due to physical changes in the process itself such as piping changes, seasonal changes in process characteristics, changes over time, etc. For this reason, the plant model may deviate significantly from the actual plant, and if control is continued without noticing this deviation, control performance will deteriorate. Also,
If a discrepancy between the model and the actual plant is noticed, the plant model must be redesigned and a controller created again, which requires a great deal of time and effort to start over from collecting process characteristic data.

[Problems to be Solved by the Invention] As described above, in the conventional technology, a deviation may occur between the plant model and the actual plant due to process fluctuations due to various causes in the plant and land, resulting in deterioration of control performance. ,
In order to prevent this performance deterioration, a great deal of time and effort is required, and there is a problem in that optimal plant control cannot be maintained for a long period of time.

Therefore, the present invention aims to provide a plant control device that can reliably grasp process fluctuations caused by various causes in a plant, easily update a plant model, and maintain optimal plant control based on this plant model over a long period of time. It is something.

[Structure of the Invention] (Means for Solving the Problem) The present invention performs plant control using a plant model. a monitoring means for monitoring whether or not there is a significant difference between the plant model designed by the identification means and the current plant model; and model updating means for updating the plant model of the plant model into the plant model designed by the identification means.

Further, it is desirable to provide an evaluation means for simulating plant control using the plant model designed by the identification means and evaluating at least one of the plant identification results, the simulation results, and the plant control results.

(Function) By taking such measures, when information regarding identification is input, plant identification is performed and a plant model is designed, and this designed plant model is used for current plant control. The plant model is compared. As a result, if there is a significant difference between the two, it is possible to update to a newly designed plant model, and control based on this updated plant model will be performed. Therefore, since the plant model can be changed in accordance with changes in process characteristics, optimal control based on the plant model can be maintained at all times.

By providing an evaluation means, it becomes possible to evaluate the control performance of a newly designed plant model. Therefore, it becomes easy to judge whether or not to update the plant model based on the evaluation result.

(Example) Hereinafter, an example of the present invention will be described with reference to the drawings.

FIG. 1 is a block diagram showing the overall configuration of this embodiment. In the figure, 1 is a process control device, 2 is a console unit equipped with a CRT display, a keyboard, etc., and 3 is various process input information A from the plant as a control target.
This is a process input/output unit that sends the control information B to the plant control device 1, receives control information B from the plant control device 1, and outputs it to the plant.

The plant control device 1 includes an identification section 4 that takes in process manual information A from the process input/output section 3 based on setting input information C from the console section 2 and performs plant identification, and an identification section 4 that identifies the plant based on the plant identification by the identification H4. The model database 5 for storing the obtained plant model information and the process human power information A from the process input/output section 3 are taken in, and the plant model stored in the model database 5 is used to create control information for the plant. The control unit 6 includes a control unit 6 that outputs the signal B, and a monitoring database 7 that stores information E regarding control results in the control unit 6. Note that the control section 6 is also connected to the console section 2, and is capable of displaying and outputting control contents. Further, the contents 1 of the model database 5 are taken into the identification section 4, and the control results thereof are evaluated.

FIG. 2 is a detailed functional block diagram of the identification section 4. As shown in FIG. The identification means 41 collects various process input information A based on the conditions necessary for plant identification stored in the condition setting database 42, identifies the plant, and identifies the process characteristics (dynamic characteristics, static characteristics) data. A plant model is designed and stored on the design model database 43.

The monitoring means 44 uses the plant model data stored in the design model database 43 and the model database 5.
The plant model data stored in the system and used for plant control by control 6 were compared, and it was monitored whether or not there was a significant difference between the two data, and it was determined that a significant difference had occurred. At times, a warning is given to the console section 2.

The evaluation means 45 takes in various process input information A and information E regarding control results stored in the monitoring database 7 as necessary, and inputs the information E into the design model database 43.
A simulation of plant control is performed using the plant model stored in the , the plant identification result, the simulation result, and the plant control result are evaluated, and the contents of the evaluation are output to the console unit 2.

The model updating means 46 updates the contents of the model database 5 to the plant model data in the design model database 43 in response to a command from the console unit 2.

Here, a method for identifying plants in the identifying means 41 will be explained.

For example, if the plant model to be identified is a system that changes in a stepwise manner as shown in ■ in Figure 3 [-th delay + dead time], its transfer function G (S) is as follows (1)
It is expressed by the formula.

G(S) − [K/ (1+TS)] e =
il) However, L is the dead time, T is the time constant, and is the gain.

Therefore, when the value of this transfer function G (S) is determined, a unique step response curve represented by ■ in FIG. 3 is obtained.

Therefore, as shown by ■ in FIG. 3, there is a dead time of a curve that theoretically approximates the response curve ■.

The plant is identified by determining the time constant T and gain K.

In this embodiment configured in this manner, the control unit 6 controls the plant as a control target according to the plant model in the model database 5. The control results at this time are stored in the monitoring database 7 and also displayed on the console section 2, so that the operator can grasp the current situation from the contents displayed on the CRT display.

In this state, the operator performs the CR operation on the console section 2.
When conditions necessary for plant identification are input via the T Nice Play setting screen or keyboard, the input conditions are stored in the condition setting database 42. Based on the conditions stored in the database 42 by the identification means 41, the process input information A is sent via the process input/output unit 3.
are collected and plant identification is performed. The plant model data designed by this plant identification is stored in the design model database 43. Then, the monitoring means 44 compares the plant model data in the design model database 43 with the current plant model data in the model database 5, and determines whether there is a significant difference between the two.

Here, if there is no significant difference between the two, nothing in particular is done, but if a significant difference occurs, a warning is issued from the console unit 2 to call the operator's attention.

In addition, the evaluation means 45 also uses the design model database 43.
A simulation of plant control is performed using a plant model in the system, and the plant identification results, simulation results, and plant control results are evaluated, and the analysis results are displayed on the CR and T displays of the console section 2.

Therefore, when a warning is issued from the console unit 2, the operator examines the accuracy of the plant model newly stored in the design model database 43 based on the analysis results displayed on the CRT display of the console unit 2, and determines whether the accuracy is sufficient. If so, a change instruction is given from the console section 2. Then, the model updating means 46 updates the plant model in the model database 5 from the current plant model to the plant model in the design model database 43, and after that, the plant model is updated by the action of the control unit 6 according to the updated plant model. Control continues.

In this way, according to this embodiment, the current plant model and the plant model designed by identifying process characteristic data are constantly monitored, and deviations between the plant model and the actual plant due to fluctuations in process characteristics due to various plant causes are detected. If this occurs, the plant model used for control can be easily changed to an appropriate plant model, so optimal plant control using the plant model can be maintained over a long period of time.

Moreover, since the control performance of the plant model to be updated can be evaluated by the evaluation means 45, reliability as a control device can be ensured.

[Effects of the Invention] As detailed above, according to the present invention, it is possible to reliably grasp process fluctuations caused by various causes in a plant, to easily update a plant model, and to perform optimal plant control based on this plant model. A plant control device that can be maintained for a long period of time can be provided.

Moreover, according to claim 2, since the control performance of the plant model to be updated can be evaluated, it is possible to provide a plant control device that can ensure sufficient reliability.

[Brief explanation of drawings]

The figures are diagrams showing one embodiment of the present invention, in which Fig. 1 is a block diagram showing the overall configuration, Fig. 2 is a detailed functional block diagram of the identification section, and Fig. 3 is used to explain the plant identification method. It is a signal waveform diagram. 1... Plant control device, 2... Console section, 3
...Process input/output unit, 4...Identification unit, 5...Model database, 6...Control unit, 7...Monitor database, 41...Identification means, 44...Monitoring Means, 45...Evaluation means, 46...Model updating means. Figure 1 Figure 3

Claims (2)

[Claims] (1) In a system that performs plant control using a plant model, an identification means for identifying the plant and designing a plant model based on input identification information, and a plant model designed by this identification means and the current state. a monitoring means for monitoring whether a significant difference has occurred between the current plant model and the plant model; and a monitoring means for monitoring whether a significant difference has occurred between the current plant model and the plant model; 1. A plant control device comprising: model updating means for updating. (2) A claim characterized in that an evaluation means is provided for performing a simulation of plant control using the plant model designed by the identification means and evaluating at least one of the plant identification results, the simulation results, and the plant control results. 1. The plant control device according to 1.