JPH0580804A - Adjusting meter - Google Patents

Abstract

PURPOSE:To correspond to a process over a wide range and to execute optimum control even if there is difference in the amount or arrangement of an object to be processed inside a blast furnace. CONSTITUTION:An adjusting meter is constituted in such a way that a pitch max. amount detecting means 33 obtaining the max. amount DR of the transition amount per unit time in pitch R concerning the rising characteristic of step response and an acceleration required time calculating means 34 calculating acceleration required time A through the use of the max. amount DR obtained by the max. amount detecting means 33 and pitch R are provided so that a differential arithmetic differentiation time parameter is adopted as the proportional amount of acceleration required time A.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a controller suitable for controlling the temperature of a batch furnace for heat treatment or the like, and more specifically, it depends on the difference in the quantity or arrangement of the objects to be treated in the furnace for each batch. The present invention relates to improvement of an adaptive method for coping with a so-called process characteristic variation that occurs.

[0002]

2. Description of the Related Art FIG. 3 is a conceptual diagram of the configuration of a conventionally known controller. Reference numeral 1 is a PID control calculation unit for inputting a process amount PV and its target set value SP, and PID control calculation unit 2 is a target process such as a furnace, and a control output M from the control calculation unit 1
It is controlled by V. 3 is a PI that inputs the process amount PV and sets it in the control calculation unit 1 according to the response status.
It is a parameter calculator that calculates D parameters and sets them. In this parameter calculation unit 3, L, R
Is a symbol representing the dead time and the gradient of the process amount PV, which are detected by the blocks 31 and 32, and based on the detected values, parameters such as the proportional band (PB), the integration time (TI) and the differential time (TD) are set. Calculation is made in each block 35, 36, 37.

The control calculation unit 1 receives a start command from the start / stop command means 4 and outputs the maximum output (MV = 100%) to the process 2 to raise the temperature of the furnace. The parameter calculation unit 3 calculates optimum parameters for control from the change (step response) of the process amount PV in the temperature rising process, and provides them to the control calculation unit 1. As a result, the control calculation unit 1 can perform the control calculation according to the optimum parameters according to the situation of the process 2 and control the process.

FIGS. 4A to 4D are control characteristic diagrams showing the step response in the conventional apparatus, which are calculated based on the change of the process amount PV, its gradient R and dead time L, and these values. The change in each parameter value such as proportional band (PB), integration time (TI), differential time (TD) is plotted. In these figures, the notation of the absolute amount is omitted.

In these figures, (a), (b),
In (c), the amount of the gradient R is similar. In (a), the dead time L is relatively small, and in (d), the gradient R is relatively small and the dead time L is larger than the others. ing. In contrast to the curved rising curve of the process amount PV in the case of (d), the situation in which the gradient R rises and holds the maximum value is that the gradient R rises first and eventually the process amount PV.
It is understood that the rise in the price will stop. In (c) and (d), the dead time L is corrected. This dead time L is generally obtained by L = elapsed time- (PV / R). Therefore, it increases as the gradient R rises, and eventually stops increasing.

In (a) and (b), since the curve of the rising curve of the process amount PV is small, the dead time L is different from the case where acceleration takes time as in (c) and (d). It is determined immediately at the rise of the quantity PV.

As described above, in the course of increasing the process amount PV, the gradient R and the dead time L are acquired as indexes indicating the characteristics of the process. It can be calculated.

PB = K1 × L × R (1) TI = K2 × L (2) TD = K3 × L (3) where K1, K2 and K3 are constants

[0009]

When such a conventional apparatus is applied to a batch furnace or the like in which the process characteristics fluctuate widely, it becomes difficult to apply it with a uniform constant. However, there is a problem that the settling time becomes long as shown in FIG.

Here, as a measure against the tendency that the settling time becomes long as shown in FIGS. 4 (c) and 4 (d), for example, when it is considered that the rise of I is slow and it is bad, the integration time TI is concerned. This is a measure to reduce the constant K2 in the equation (2). Further, when it is considered that the proportional band is too narrow and is in a vibrational state, the constant K1 of the equation (1) relating to the proportional band PB is used.
Is a measure to increase. Further, when it is considered that the braking is insufficient, it is a measure to increase the constant K3 of the equation (3) related to the differential time TD.

All of them have characteristic effects, but have the following problems. That is, if the constants K1 to K3 are changed,
In some cases, all of (a) to (d) are affected, and the satisfactory characteristics may be deteriorated. Further, for example, it is impossible to distinguish the characteristics (b) and (c) by looking at the dead time L and the gradient R, and it is impossible to consider the proper use of constants from the characteristics of the process.

FIG. 5 is a diagram in which the characteristics of (a) to (d) of FIG. Although the absolute amount of the numerical value is omitted here, it does not matter in the relative comparison whether the dead time L is 5.0 seconds or 5 minutes. L / T is a so-called equivalent dead time / equivalent time constant ratio.

The present invention has been made in view of the above circumstances, and is a controller capable of performing good temperature control by adapting to characteristic changes caused by differences in the amount and arrangement of heat-treated objects in a batch furnace or the like. The purpose is to provide.

[0014]

SUMMARY OF THE INVENTION The present invention for solving such a problem is a control calculation unit for inputting a target set value and a process amount, performing a proportional calculation, an integral calculation and a differential calculation and sending a control output to a process. And the process time is input, the dead time (L) relating to the rising characteristic of the step response and the slope (R) are obtained as process evaluation indexes, and the proportional, integral, and differential operations are set in the control operation unit. In a controller equipped with a parameter calculator for setting parameters, a maximum gradient amount detecting means for determining a maximum transition amount (DR) of a gradient (R) per unit time relating to a rising characteristic of a step response, and a maximum gradient amount detecting means. The maximum amount (D
R) and the gradient (R) are used to provide an acceleration required time calculating means for calculating an acceleration required time (A), and a differential calculation (differential time) parameter is adopted as a proportional amount of the acceleration required time (A). It is a controller characterized by doing so.

[0015]

In the controller of the present invention, as the evaluation index for identifying the process, in addition to the dead time L and the gradient R related to the rising characteristic of the step response, the maximum amount DR of the transition amount of the gradient R per unit time is DR. By adopting the concept of the required acceleration time A calculated using the gradient R and the gradient R and using it as the basis of the differential time, it becomes possible to flexibly cope with the fluctuation of the process characteristics.

[0016]

Embodiments of the present invention will be described in detail below with reference to the drawings. FIG. 1 is a configuration block diagram of an embodiment of the present invention. In the figure, the same parts as those in FIG. 3 are designated by the same reference numerals. Reference numeral 1 is a target setting value SP and the process amount PV from the process 2 is input, and a control operation unit for performing a proportional operation, an integral operation, a differential operation and sending a control output MV to the process 2 is input with the process amount PV. In a parameter calculation unit that obtains a dead time L related to the rising characteristic of the step response and a gradient R as evaluation indices that show the characteristics of the process, and sets parameters for proportional, integral, and differential calculations set in the control calculation unit 1. is there.

In the parameter calculation unit 3, 31 is a detecting means for detecting the dead time L in the rising characteristic of the step response of the process amount PV, and 32 is a detecting means for detecting the gradient R as well. It is the same as that provided in the device. Further, 35 is a means for calculating the integration time TI, 36 is a means for calculating the proportional band PB, and these are, as described above, using the dead time L and the gradient R obtained as the process evaluation index (1). ，
The integration time and the proportional band are calculated according to the equation (2).

Reference numeral 33 is a gradient maximum amount detecting means for obtaining the maximum amount DR of the transition amount of the gradient R per unit time relating to the rising characteristic of the step response. For example, the variation amount of the gradient R is plotted and the maximum value DR is obtained. Is configured to detect. Reference numeral 34 is an acceleration required time calculating means for calculating an acceleration required time A using the maximum amount DR and the gradient R obtained by the maximum amount detecting means 33. Specifically, the acceleration required time A is
It is calculated by the equation (4).

A = R / DR (4) The required acceleration time A obtained here is the differential time calculating means 3
7, the differential operation (differential time) parameter TD is used as the proportional amount (base) of the differential operation parameter TD and is obtained according to the equation (5).

TD = K3 × A (5) In the conventional device, the differential time TD is calculated by using the dead time L as shown in the equation (3). However, in the present invention, As described above, the feature is that the acceleration required time A is used instead of the dead time L. That is, when the required acceleration time is small, there is no problem in so-called PI control, and when the dead time L is large, the differential time TD is calculated from the required acceleration time A as compared with the conventional apparatus which calculates the differential time TD. It is said that doing is more adaptable.

FIGS. 2A to 2D are control characteristic diagrams showing the step response in the apparatus of the present invention.
The gradient R of V, the dead time L, and the required acceleration time A are respectively detected, and changes in parameters such as proportional band (PB), integration time (TI), and differential time (TD) based on these values are plotted. , And has a corresponding relationship with FIG.

In these figures, in (c) and (d),
Despite the integration time TI which is the same as that of the conventional device, the increase of the I output amount is good. This is because the application of the present invention causes the amount of D to brake the process amount PV and leave a large deviation. , I, the deviation is gradually reduced as the output amount increases.

[0023]

As described in detail above, according to the present invention, as an evaluation index showing the characteristics (dynamic characteristics) of a process,
While adopting the new concept of acceleration time A,
Since it is based on the differential time, it is possible to support a wide range of processes, and optimal control can be performed even if there are differences in the amount and arrangement of the objects to be processed in the furnace.

[Brief description of drawings]

FIG. 1 is a configuration block diagram of an embodiment of the present invention.

FIG. 2 is a control characteristic diagram showing a step response in the device of the present invention.

FIG. 3 is a conceptual diagram of the configuration of a conventionally known controller.

FIG. 4 is a control characteristic diagram showing a step response in a conventional device.

FIG. 5 is a diagram in which the characteristics of FIG. 4 are arranged and compared relative to each other.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 control calculation part 2 process 3 parameter calculation part 31 dead time detection means 32 gradient detection means 33 maximum gradient amount detection means 34 acceleration required time calculation means 35 integration time (TI) calculation means 36 proportional band (PB) calculation means 37 differential time (TD) calculation means

Claims (2)

[Claims] 1. A control calculation unit for inputting a target set value and a process amount, performing a proportional calculation, an integral calculation and a differential calculation and sending a control output to a process, and a control calculation unit for inputting a process amount and a rising characteristic of a step response thereof. Dead time (L),
A controller having a gradient (R) as a process evaluation index and a parameter calculator for setting parameters for proportional, integral, and derivative calculations to be set in the control calculator is related to the rising characteristic of step response. Gradient maximum amount detecting means for obtaining the maximum amount (DR) of the transition amount of the gradient (R) per unit time, and acceleration using the maximum amount (DR) and the gradient (R) obtained by the maximum amount detecting means. A controller characterized in that it is provided with an acceleration required time calculating means for calculating a required time (A), and a differential calculation (differential time) parameter is adopted as a proportional amount of the acceleration required time (A). 2. The acceleration required time (A) is A = (R / D
The controller according to claim 1, which is calculated by R).