JPS62127902A - process control equipment - Google Patents

Abstract

PURPOSE:To improve the controllability, especially, the responsiveness regardless of the size of a set value and the size of a set value change width by providing a difference detecting part, a difference holding part, a difference differentiating part and an adder part. CONSTITUTION:When a difference detecting part 8 detects a setting part output SV, at a difference holding part 9, the width of the change and the increasing and decreasing directions of the change are stored, and only a setting time (t) of a built-in time limit circuit is held. At a difference differentiating part 10, the signal is differentiated and outputted as an output signal MV 2 based on the size and the direction of a difference signal DELTASV, which is the output of the difference holding part 9. The output signal MV 2 is added to an output signal MV 1 from an adjusting part 4 and outputted to an operating part 6 by an adder part 5.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to a process control device, and particularly to a process control device suitable for improving controllability when changing set values. .

[Background of the invention]

As one method for improving controllability when changing set values, a method is known, for example, as shown in Japanese Patent Laid-Open No. 57-130103, which adds the power of the adjustment section and the output of the setting section. Although this method improves responsiveness, it is necessary to determine the ratio constant of the ratio setter each time depending on the magnitude of the set value.

Furthermore, as disclosed in Japanese Patent Application Laid-Open No. 59-71507, a method is known in which the operating force of the adjustment section is adjusted based on the magnitude of the difference between the set value and the measured value. This method enables fine tracking of the control amount, but when the deviation is small, the multiplication factor of the single multiplication is smaller than 1, which affects the response.

[Purpose of the invention]

The present invention has been made in view of the above, and its purpose is to provide a process control device that can improve controllability, particularly responsiveness, regardless of the size of the set value or the range of change in the set value. It is about providing.

[Summary of the invention]

The present invention is characterized by a difference detection section that detects the change width and increase/decrease direction of the set value from the setting section, a difference holding section that holds the difference signal from the difference detection section for a predetermined period of time, and a difference holding section that completely differentiates the difference signal. The present invention is characterized in that it is completely equipped with a difference differentiation section and an addition section that adds the output signal of the difference differentiation section to the output signal from the adjustment section.

[Embodiments of the invention]

The present invention will be described in detail below with reference to the embodiment shown in FIG. 1 and FIG. 2.

FIG. 1 is a schematic configuration diagram showing an embodiment of the process control apparatus of the present invention, and FIG. 2 is a time chart for explaining the operation of the main parts of FIG. 1.

In FIG. 1, 1 is the set value Sv that the control device should reach.
2 is a detection section that outputs the process amount from the controlled object as a measured value Pv; 3 is a comparison section that compares the set value SV and the measured value PV to obtain a deviation signal; 4 is a comparison section that obtains a deviation signal. Input, perform all PID calculations, and output the result as the output signal MV.
5 is an adder that adds the output signal MVI and an output signal MV2 of the difference differentiator 10, which will be described later, and outputs the result as the output signal MV; 6 is the output signal M;
This is an operation unit that converts an operation amount suitable for Vt-process 7. 8 is a difference detection section that detects the range of change in the set value SV and the direction of increase/decrease in the change, and 9 is a built-in time limit circuit that starts with the output of the difference signal section and stops after the set time, and outputs the difference signal ΔSv. A difference holding section 10 is a difference differentiation section that completely differentiates the difference signal ΔSv, performs all upper and lower limit signal control, and outputs the result as an output signal MV2.

Note that the difference detection section 8, difference holding section 9, and difference differentiation section 10 in FIG.
Since this is a part related to the present invention, its operation will be further explained in detail with reference to FIG.

In FIG. 2, (a) shows the set value SV, (b) shows the difference signal ΔSv1, and (C) shows the operation of the time limit circuit built into the difference detection section 9.
(d) shows the waveform of the output signal MV2, (e) shows the waveform of the output signal MV, and the left half shows the set value S which is the output of the setting section 1.
The right half shows the case where V increases, and the right half shows the case where it decreases. Now, when the setting section output Sv is detected by the difference detection section 8, the difference holding section 9 stores the width of the change and the increase/decrease direction of the change, and holds it for the set time t of the built-in time limit circuit. The difference differentiating section 10 differentiates the difference signal ΔSV, which is the output of the difference holding section 9, based on the magnitude and direction and outputs it as an output signal MV2. This output signal MV2 is added to the output signal MVI from the adjustment section 4 by the addition section 5, and is output to the operation section 6.

According to the embodiment of the present invention described above, when there is no change in the setting value, the control is performed using the output signal MVI of the adjustment section 4, and only when there is a change in the setting value, the output signal MV2 of the difference differentiating section 10 is controlled by MVI.
It will be superimposed on the VI. Furthermore, since the output signal MV2 to be superimposed is calculated based on the magnitude and direction of increase/decrease of the setting value change, improvements in both controllability and responsiveness can be achieved at the same time. In particular, if the adjustment section 4 includes a differential operation, it is possible to easily configure a flow rate, pressure, liquid level control device, etc., which are considered undesirable in terms of control.

In the above explanation, in order to make it easy to understand, a method for detecting a change in a set value has been described. The same effect can be obtained by using the same signal as a signal.

〔Effect of the invention〕

As explained above, according to the present invention, controllability is maintained regardless of the size of the set value or the size of the set value change range.

In particular, this has the effect of improving responsiveness.

[Brief explanation of drawings]

FIG. 1 is a schematic configuration diagram showing an embodiment of the process control apparatus of the present invention, and FIG. 2 is a time chart for explaining the operation of the main parts of FIG. 1... Setting section, 2... Detecting section, 3... Comparing section, 4
...adjustment section, 5.addition section, 6.operation section, 7.
... Process, 8... Difference detection section, 9... Difference holding section,
1o...Difference differential part.

Claims (1)

[Claims] 1. The PI is set according to the deviation amount obtained by comparing the set value set in the setting section and the measured value of the process amount from the controlled object.
In a process control device equipped with an adjustment section that performs a D calculation, a difference detection section that detects the width and increase/decrease direction of a change in a set value from the setting section; and a difference detection section that holds a difference signal from the difference detection section for a predetermined period of time. a holding section; a difference differentiating section that differentiates the difference signal;
A process control device comprising: an addition section that adds the output signal of the difference differentiation section to the output signal from the adjustment section.