JPH1139003A - Controller - Google Patents

Abstract

PROBLEM TO BE SOLVED: To correct an input value to make an indicated value and to enable a finer correction of the input value at the time of controlling on the basis of the indicated value. SOLUTION: For example, real reference temperatures (20 deg.C and 100 deg.C) inside an electric furnace being an object to be controlled are measured with an temperature sensor that is a measurement standard and a correction equation is predetermined so that indicated temperatures (190 deg.C and 90 deg.C) of a temperature adjusting meter at that time becomes equal to the reference temperatures (20 deg.C and 100 deg.C). After this, an input temperature of the temperature adjusting meter is corrected by this correction equation to make the indicated temperature.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a controller such as a temperature controller, and more particularly, to a controller which corrects an input value into an indicated value and performs control based on the indicated value.

[0002]

2. Description of the Related Art In a controller of this kind, for example, a temperature controller, when it is physically difficult to dispose a temperature sensor sufficiently close to an object to be measured, the temperature sensor measures the temperature. The temperature input thus input to the temperature controller will be lower than the actual temperature of the object to be measured.
For example, there is a case where the actual temperature of the measurement target is 100 ° C., while the temperature measured by the temperature sensor is 90 ° C.

In order to cope with such a case, some temperature controllers have an input correction function, and the difference between the temperature measured by the temperature sensor and the actual temperature of the object to be measured is described in the above example. Then, by setting 10 (= 100-90) as a correction value (shift value) in the temperature controller in advance, the correction value is added to the input temperature from the temperature sensor and displayed as the indicated temperature. The control is performed so that the indicated temperature becomes the target temperature.

[0004]

However, the conventional input correction simply adds (or subtracts) a preset correction value to the input temperature from the temperature sensor as described above. Because of the so-called one-point correction, for example, the temperature control has not been started,
Even when the temperature is at C, in the above example, the correction value 10 is added, and 35 ° C. is displayed as the instructed temperature at room temperature.

[0005] As described above, since the temperature far from room temperature is displayed as the indicated temperature despite the room temperature, the user misunderstands that there is a problem with the temperature sensor or the like. There is a fear.

Therefore, at a relatively high temperature near the set temperature at which the temperature control is actually performed, the same correction as that of the conventional example is performed. It is desired that the indicated temperature be kept at room temperature.

SUMMARY OF THE INVENTION The present invention has been made in view of the above points, and has as its object to provide a controller capable of performing more precise correction of an input value than a conventional example.

[0008]

In order to achieve the above-mentioned object, the present invention is configured as follows.

That is, the present invention provides a controller which corrects an input value to an indicated value and performs control based on the indicated value, wherein a reference value measured by a reference device and a value of the controller at that time are used. Means for preliminarily determining a correction equation based on the indicated value so that the indicated value becomes equal to the reference value, and correcting means for correcting an input value to an indicated value according to the correction equation, The determining means determines the correction formula from at least two sets of values when the reference value and the indicated value at that time are set as one set.

The correction equation may be a linear equation.

[0011] The controller of the present invention may be a temperature controller that sets the input value as a temperature input value, sets the indicated value as a temperature indicated value, and performs temperature control based on the temperature indicated value.

[0012] One of the reference values may be a temperature value at room temperature.

According to the controller of the present invention, based on at least two sets of reference values and the corresponding indicated values, a correction equation, for example, a primary equation is preliminarily corrected so that the indicated value is equal to the reference value. After the determination, the input value is corrected according to the correction formula to obtain the instruction value. Therefore, it is possible to perform a finer and stricter correction than the conventional example in which the correction is performed using the same correction value (shift value) regardless of the input value. become.

[0014]

Embodiments of the present invention will be described below in detail with reference to the drawings.

FIG. 1 is a configuration diagram of a temperature control system according to one embodiment of the present invention.
Is an electric furnace as a control object, and 1 is a temperature controller as a controller according to the present invention. The temperature controller 1 is based on an output of a temperature sensor 4 such as a thermocouple attached to an outer wall of the electric furnace 10. In addition, the power supply to the heater 11 of the electric furnace 10 is controlled via an electromagnetic switch (not shown) so that an instruction temperature described later matches a preset target temperature.

The temperature sensor 4 is provided with an electric furnace 10 so as to extend the service life and facilitate maintenance and the like.
In the vicinity of the control temperature, the input temperature measured by the temperature sensor 4 and input to the temperature controller 1 becomes lower than the actual temperature inside the electric furnace 10 to be controlled. ing.

For this reason, the temperature controller 1 of this embodiment
Corrects the input temperature from the temperature sensor 4 to
And the indicated temperature according to the actual temperature inside the
It has an input correction function of performing control based on the instructed temperature and, unlike the conventional example in which a correction value (shift value) is simply added or subtracted, the correction value is not limited to a relatively high temperature near the control temperature, but also around a room temperature. Electric furnace 1 even at relatively low temperatures
Finer corrections can be made so that the indicated temperature matches the actual temperature of 0.

FIG. 2 is a perspective view of the temperature controller 1 of FIG. 1. On the front of the temperature controller 1, a first display section 2a for displaying a current temperature (instructed temperature) and the like, and a set temperature and the like are shown. And a second display section 2b for displaying the same, and various operation keys 3 such as a mode key, a down key and an up key are arranged below the LED display section 2.

FIG. 3 is a block diagram showing the internal configuration of the temperature controller 1 of FIG. 1. Parts corresponding to FIG. 2 are denoted by the same reference numerals.

The temperature controller 1 performs an A / D conversion unit 5 for A / D converting an input from the temperature sensor 4 and performs a correction operation described later on the input data from the A / D conversion unit 5. Then, the designated temperature (current temperature) is calculated and displayed on the LED display unit 2 described above, and the designated temperature is set to the set temperature in accordance with the setting input from the setting unit 6 including the various operation keys 3 described above. And a control operation unit 8 for providing a control output to the output unit 7. The control operation unit 8 is configured by a microcomputer.

The temperature controller 1 of this embodiment is configured as follows so that a more detailed correction of a temperature input can be performed as compared with the conventional example.

That is, in the temperature controller 1, the indicated temperature is equal to the reference temperature based on the reference temperature inside the electric furnace 10 measured by the reference device and the indicated temperature of the temperature controller 1 at that time. Is determined in advance so that
The input temperature is corrected by this correction formula to obtain the designated temperature.

FIG. 4 is a characteristic diagram for explaining the principle of the correction of the temperature input. The solid line indicates the actual temperature inside the electric furnace 10 as a reference temperature measured by a highly accurate temperature sensor as a reference device. , And the dashed line indicates the indicated temperature before correction displayed by the temperature controller 1.

In this embodiment, the indicated temperature is corrected from the two sets of the reference temperature measured by the high-precision temperature sensor and the indicated temperature of the temperature controller 1 so that the indicated temperature becomes equal to the reference temperature. The formula is determined in advance.

That is, as shown in FIG. 4, when the actual temperature inside the electric furnace 10 is, for example, 20 ° C., the temperature measured by the temperature sensor 4 installed on the outer wall of the electric furnace 10 is The indicated temperature displayed by the controller 1 is, for example, 19 ° C., and when the actual temperature inside the electric furnace 10 is, for example, 100 ° C., a temperature sensor installed on the outer wall of the electric furnace 10 The indicated temperature measured at 4 and displayed on the temperature controller 1 is, for example, 90 ° C. because it is not corrected.

That is, when the reference temperatures which are the actual temperatures of the electric furnace 10 are 20 ° C. and 100 ° C., the input of the temperature sensor of the temperature controller 1 is 19 ° C. and 90 ° C. Therefore, the indicated temperatures are 19 ° C. and 90 ° C. Therefore, the indicated temperatures of 19 ° C. and 90 ° C.
Reference temperature 20 ° C., which is the actual temperature of the electric furnace 10,
The correction equation is determined as follows so as to be equal to 0 ° C.

FIG. 5 is a diagram showing the relationship between the input temperature and the indicated temperature of the temperature controller 1 of this embodiment. In FIG. 5, a solid line indicates a correction straight line, and a dashed line indicates a correction line. The previous characteristic is shown.

Before the correction, as indicated by the dashed line, the designated temperature is 19 ° C. and 90 ° C.
° C and 90 ° C, which are lower than the reference temperatures 20 ° C and 100 ° C which are the actual temperatures inside the electric furnace 10.

In the correction straight line shown by the solid line, the temperature input 1
For 9 ° C and 90 ° C, the indicated temperature is the reference temperature 20 ° C.
° C and 100 ° C.

This correction straight line is represented by (x, y) = (19, 20) and (90, 10) when y = ax + b.
0) is determined by determining a and b as straight lines passing through two points.

[0031]

Thus, the correction equation is y = (80/7)
1) x-1.4, the indicated temperature y is calculated by correcting the input temperature x of the temperature sensor 4 according to the above-described correction formula, and the temperature control is performed based on the calculated indicated temperature y. Will be.

According to this correction equation, a temperature input of 19 ° C.,
At 90 ° C., the indicated temperature is substantially equal to the reference temperatures 20 ° C. and 100 ° C. which are the actual temperatures inside the electric furnace 10.

The correction formula is determined by setting the temperature controller to, for example, a correction formula determination mode, and setting two values (2) of the reference temperature measured by the reference device and the indicated temperature at that time.
By inputting 0 ° C, 19 ° C) and (100 ° C, 90 ° C), the correction formula is determined as described above,
Thereafter, by canceling the determination mode, the correction is performed according to the correction formula.

The determination of the correction formula and the correction by the correction formula are performed by the microcomputer described above.

As described above, the input temperature is corrected by the primary correction formula to obtain the designated temperature. Therefore, as in the conventional example in which the correction value (shift value) is added or subtracted, the input temperature is simply increased. In, the correction is effective, but at low temperatures around room temperature, the indicated temperature does not become a value far from the actual temperature, and at high and low temperatures, the indicated temperature becomes a value corresponding to the actual temperature. .

In the above-described embodiment, in order to determine the correction formula, it is necessary to set the temperature at 20 ° C. near room temperature and 10 ° C. near control temperature.
Although the reference temperature was measured in advance at two points of 0 ° C. by the reference device, as another embodiment of the present invention, in a static state near room temperature, the temperature of the inside of the electric furnace 10 and the temperature of its outer wall are equal. Assuming, the correction formula may be calculated by measuring only the vicinity of the control temperature with the reference device and measuring with the temperature controller 1. In this case, only the temperature near the control temperature need be measured, and the correction formula can be easily determined.

In the above-described embodiment, the correction formula is determined based on the two sets of reference values of the low temperature side and the high temperature side and the indicated value at that time. However, as another embodiment of the present invention, Alternatively, a different reference value and an indicated value at that time may be measured, and a correction formula may be determined from three or more values by the least square method or the like.

[0039]

As described above, according to the present invention, based on at least two sets of reference values and corresponding indicated values, a correction expression, such as a linear expression, is corrected so that the indicated value becomes equal to the reference value. Since the equation is determined in advance and the input value is corrected in accordance with this correction equation to obtain the indicated value, a finer and stricter correction than in the conventional example in which the same correction value (shift value) is used regardless of the input value Can be performed.

In particular, by applying to a temperature controller,
Not only at a high temperature near the control temperature but also at a low temperature near room temperature, a temperature corresponding to the actual temperature of the control target is displayed as the indicated temperature, and the temperature is controlled based on the indicated temperature.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a system using a temperature controller according to the present invention.

FIG. 2 is a perspective view of the temperature controller of FIG. 1;

FIG. 3 is a block diagram of the temperature controller of FIG. 1;

FIG. 4 is a diagram illustrating the principle of correction according to the present invention.

FIG. 5 is a diagram showing a correction straight line according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Temperature controller 4 Temperature sensor 8 Control calculation part 10 Electric furnace

Claims (4)

[Claims] 1. A controller that corrects an input value to an indicated value and performs control based on the indicated value, wherein a reference value measured by a reference device and an indicated value of the controller at that time are used. A means for determining a correction formula in advance so that the indicated value is equal to the reference value, and a correcting means for correcting an input value in accordance with the correction formula and setting the corrected value to an indicated value. A controller, wherein the correction formula is determined from at least two sets of values when the reference value and the indicated value at that time are set as one set. 2. The controller according to claim 1, wherein the correction equation is a linear equation. 3. The controller according to claim 1, wherein the input value is a temperature input value, the indicated value is a temperature indicated value, and temperature control is performed based on the temperature indicated value. 4. The controller according to claim 3, wherein one of the reference values is a temperature value at room temperature.