JPWO2018087911A1 - Temperature measuring device, temperature indicator and temperature controller - Google Patents

Abstract

Among the sensors for measuring the temperature of the same control target, when the value of the reference sensor exceeds a predetermined value, the sensor used for measurement is switched to the switching destination sensor (S310, S320, S340, S350). In the switching process, the sudden change in the measured value at the sensor switching time is reduced by outputting the value which is proportionally corrected with respect to the switching time during the switching time set in advance as the value of the sensor (S330) Make it possible.

Description

  The present invention relates to a temperature measurement device, a temperature indicator and a temperature controller based on inputs from a plurality of temperature sensors.

  As a sensor for measuring a temperature, a thermocouple is widely used because of its excellent stability, heat resistance, response, and the like. However, there is no known thermocouple thermometer that can measure temperature accurately from low temperature to high temperature. Therefore, in the case where temperature control is performed over a wide range from low temperature to high temperature, there is a problem that the measurement accuracy is degraded when temperature measurement is performed using one sensor. In order to cope with such a problem, Patent Document 1 discloses a temperature measurement method using two sensors having different temperature characteristics.

Japanese Patent Application Laid-Open No. 7-139885

The technology disclosed in Patent Document 1 is a temperature measurement method using a high-temperature thermocouple thermometer and a low-temperature thermocouple thermometer in furnace temperature measurement, and the furnace temperature exceeds a predetermined value. When the temperature rises, it switches to a high temperature thermometer. However, because the characteristics of the high-temperature thermocouple and the characteristics of the sensor elements in the low-temperature thermocouple are different, the measured values by the respective sensors do not match. Therefore, when switching the sensor, there is a problem that a sudden change occurs in the measured value.
A sudden change in the measured value may increase the time to stability and cause deterioration of controllability, particularly when controlling the temperature of the object based on the deviation between the target value and the current value, as in feedback control. .

  The present invention, in view of the above points, in temperature measurement using a plurality of temperature sensors, a temperature measuring device, a temperature indicator and a temperature controller capable of reducing sudden changes in measured values when switching the sensors. Intended to provide.

(Configuration 1)
Among the sensor inputs that measure the temperature of the same measurement object, the sensor input used for the measurement from the reference input that is the input from the reference sensor that is the measurement reference to the switching destination input that is the input from the switching destination sensor And a switching processing unit for switching
The switching processing unit
When the value of the reference input does not exceed the predetermined value, the value of the reference input is output as the measurement value of the measurement target,
When the value of the reference input exceeds the predetermined value and the elapsed time from the time when the predetermined value is exceeded is less than a predetermined switching time, the point at the time when the reference input exceeds the predetermined value A corrected measurement value corrected based on the deviation amount between the value of the switching destination input and the value of the reference input is calculated, and the corrected measurement value is output as the measurement value of the measurement target,
When the value of the reference input exceeds the predetermined value and the elapsed time since the point exceeds the predetermined value is equal to or longer than the switching time, the value of the switching destination input is the measured value of the measurement target Output as
A temperature measuring device characterized by
(Configuration 2)
The switching processing unit is proportional to the switching time based on the switching time and a deviation between the value of the switching destination input and the value of the reference input when the reference input exceeds the predetermined value. The temperature measurement device according to claim 1, wherein the correction measurement value is calculated by performing correction.
(Configuration 3)
The temperature measurement device according to Configuration 1 or 2, wherein the switching processing unit calculates the correction measurement value according to the following equation.

ＰＶａｄｊは前記補正測定値、Ｚは前記切換先入力の値、Ｅは前記所定値を超えた時点における前記切換先入力の値と前記基準入力の値との偏差量、Ｙは前記切換時間、Ｔは前記所定値を超えた時点からの経過時間を表す。
（構成４）
前記切換処理部が、前記所定値を超えた時点における前記偏差量に基づき前記切換時間を決定することを特徴とする構成１から３の何れかに記載の温度測定装置。
（構成５）
構成１から４の何れかに記載の温度測定装置と、前記温度測定装置からの出力を表示する表示部と、を備えることを特徴とする、温度表示計。
（構成６）
構成１から５の何れかに記載の温度測定装置、又は温度表示計と、
前記温度測定装置からの出力と、目標温度に基づいて、前記測定対象の温度を前記目標温度となるように制御するための制御信号を算出する算出部と、
前記測定対象に直接又は他の装置を介して前記制御信号を出力する出力部と、
を備えることを特徴とする温度調節計。

PVadj is the correction measurement value, Z is the value of the switching destination input, E is the deviation between the value of the switching destination input and the value of the reference input when the predetermined value is exceeded, Y is the switching time, T Represents an elapsed time from the time when the predetermined value is exceeded.
(Configuration 4)
5. The temperature measurement device according to any one of configurations 1 to 3, wherein the switching processing unit determines the switching time based on the deviation amount at the time when the predetermined value is exceeded.
(Configuration 5)
A temperature indicator, comprising: the temperature measurement device according to any one of Configurations 1 to 4; and a display unit that displays an output from the temperature measurement device.
(Configuration 6)
A temperature measuring device according to any one of configurations 1 to 5, or a temperature indicator,
A calculation unit that calculates a control signal for controlling the temperature of the measurement target to the target temperature based on the output from the temperature measurement device and the target temperature;
An output unit that outputs the control signal to the measurement target directly or through another device;
A temperature controller characterized by comprising.

  According to the temperature measurement device, the temperature display meter, and the temperature controller of the present invention, it is possible to reduce sudden changes in measured values even when temperature measurement is performed by switching a plurality of sensors.

It is a schematic block diagram which shows the temperature controller of Embodiment 1 which concerns on this invention. It is a conceptual diagram explaining the relation between switching of a sensor and a measured value. It is a flowchart explaining operation | movement of the temperature controller of Embodiment 1 which concerns on this invention. It is a conceptual diagram which shows the measured value and output value at the time of switching of a sensor by the conventional temperature controller in PID control. It is a conceptual diagram which shows the measured value at the time of switching of a sensor by the temperature controller of this invention in PID control, and an output value. It is a schematic block diagram which shows the temperature indicator of Embodiment 2 which concerns on this invention.

  Hereinafter, an embodiment for carrying out the present invention will be described according to the attached drawings.

First Embodiment
FIG. 1 is a schematic block diagram showing a portion related to the present invention of a temperature controller according to an embodiment of the present invention.
The temperature controller 100 is a device that controls the temperature of the control object 130 based on input values (hereinafter also referred to as PV1 and PV2) from the sensors 141 and 142 that measure the temperature of the control object 130, and the temperature of the control object 130 And an output unit 120 that outputs a control signal to the control target.
The temperature measurement device 150 is a device that measures the temperature of the control target 130 based on PV1 and PV2, and includes a switching processing unit 110 that performs sensor switching processing. Moreover, the A / D conversion part (not shown) which A / D converts the voltage value input from the sensors 141 and 142 is provided.

The temperature controller 100 performs temperature control of the controlled object 130 such as a heater, and the target device so that the temperature of the controlled object 130 itself or the temperature of the controlled object 130 becomes the set target value. Directly or via another device to output the control signal as an output value (hereinafter also referred to as MV).
The temperature measurement device 150 is configured to be able to receive the input from the sensors 141 and 142.
The switching processing unit 110 is configured to receive PV1 and PV2 and perform sensor switching processing to be described later, and to output a temperature measurement value of the controlled object 130 (hereinafter referred to as PV) to the output unit 120. Further, the switching processing unit 110 is configured to be able to record various values such as PV1 and PV2.
The output unit 120 is configured to perform PID calculation based on the temperature measurement value and the target value input from the switching processing unit 110, and to output an output value (MV) that is the calculation result to the control target 130.
The sensors 141 and 142 are constituted by thermocouples.

FIG. 2 is a conceptual diagram for explaining the relationship between the switching of the temperature sensor and the measured value.
As described above, even if the temperature of the same control target is measured, the measured value for each sensor is different due to the difference in sensor characteristics. The relationship between sensor switching and measured values in such a situation is shown in FIG.
The upper part of FIG. 2 shows the relationship between sensor switching and measured values according to the conventional method. If the sensor used for measuring the temperature is simply switched from the sensor 141 to the sensor 142 when the input value from the sensor 141 exceeds a predetermined value, the measured value may be suddenly changed.
The lower part of FIG. 2 shows the relationship between sensor switching by the temperature controller 100 according to the first embodiment and measured values. PVadj represents a corrected measurement value described later. As shown in this figure, the temperature controller 100 according to the first embodiment reduces the sudden change of the measured value by changing the value of the sensor 141 proportionally with the passage of time.

<Operation>
Next, the processing operation of the temperature controller 100 according to the first embodiment of the present invention will be described with reference to the flowchart of FIG.

The process of FIG. 3 is executed every preset cycle or every operating cycle of the temperature controller 100.
Hereinafter, the process is also simply referred to as switching process.
In the present embodiment, a reference sensor that is a sensor serving as a reference for temperature measurement is the sensor 141, and a switching destination sensor is the sensor 142.
First, in step 300, the temperature measurement device 150 acquires PV1 and PV2. Then, the temperature measurement device 150 stores the acquired values into corresponding variables in the switching processing unit 110. In addition, 0 is stored as an initial value of each variable.

  In the subsequent step 310, the switching processing unit 110 determines whether the value of PV1 is equal to or greater than a predetermined value. If PV1 is less than the predetermined value, the process proceeds to step 350 (step 310: No → step 350). In step 350, the switching processing unit 110 outputs the measured value of PV 1, that is, the measured value of the sensor 141 to the output unit 120 as the measured value of the control target 130, and stores it in the corresponding variable in the switching processing unit 110. The predetermined value serving as the switching threshold is set near the upper limit value of the usable temperature range of the sensor 141.

On the other hand, when it is determined in step 310 that the value of PV1 is equal to or greater than the predetermined value, the process proceeds to step 320, and sensor switching processing is performed. (Step 310: Yes → Step 320).
In step 320, the switching processing unit 110 determines whether the elapsed time from the start of the switching process is equal to or less than the switching time set in advance. If the elapsed time is larger than the switching time, ie, the switching process is completed, the process proceeds to step 340 (step 320: No → step 340). In step 340, switching processing unit 110 outputs PV 2, that is, the measured value of sensor 142 to the output unit 120 as the measured value of controlled object 130, and stores it in the corresponding variable in switching processing unit 110. .
The switching time may be set in advance or may be input by an input unit (not shown) or the like, and it may be appropriately determined depending on how much sudden change of the measured value is permitted. Good.
Moreover, about elapsed time, measurement is started from the time of transfering to step 320.
Further, the switching processing unit 110 is configured to turn on a switching flag, which is a flag signal indicating whether or not the switching processing has been performed when the process proceeds to step S320. When the switching flag is ON, the process proceeds to step 320 after the start of the switching process.

On the other hand, if the elapsed time is equal to or less than the switching time in step 320, the process proceeds to step 330 (step 320: Yes → step 330).
In step 330, the switch processing unit 110 calculates a correction measurement value for sensor switching. The switch processing unit 110 outputs a corrected measurement value (hereinafter also referred to as a correction PV) calculated as the following equation as a measurement value of the control target 130 to the output unit 120, and in the switch processing unit 110. Store to the corresponding variable.

  In Equation 2, PVadj is a correction PV, Z is a value of PV2 of the switching destination input, E is a deviation between PV2 and PV1 when PV1 exceeds a predetermined value, Y is the switching time, and T is the predetermined value. Represents the elapsed time since the

FIG. 4 is a conceptual view showing measured values and output values when the sensor is switched by the conventional method.
A solid line represents PV output from the switching processing unit 110. The broken line represents the MV value output from the output unit 120.
By switching the sensor when the predetermined value is exceeded, a sudden change of the measured value occurs.
In addition, the output value at that time is greatly disturbed.

FIG. 5 is a conceptual view showing measured values and output values when the switching process is performed in the temperature controller 100 according to the present embodiment.
Even if the sensor is switched when the predetermined value is exceeded, sudden changes in the measured value are reduced.
There is no large disturbance in the output value, and the time to reach the stable state is shortened as compared with the case of FIG.
In FIGS. 4 and 5, the unit of PV is ° C., and the unit of MV is%. Here, PV and MV are described on the same plane for the sake of convenience of waveform confirmation.

As described above, according to the temperature controller 100 of the first embodiment, when temperature measurement is performed by switching a plurality of sensors, the correction output value is calculated in proportion to the switching time. It is possible to reduce sudden changes in value.
Further, even when temperature control is performed by switching a plurality of sensors, it is possible to prevent a decrease in controllability.
Further, as described in the above-mentioned equation 2, when switching processing is started, switching is performed reliably when the switching time set in advance has elapsed. It is possible to predict the time cost of
Further, in the switching process, the correction measurement value is calculated based on the deviation between PV2 and PV1 when PV1 exceeds a predetermined value. Therefore, since it is not necessary to observe the input of the reference sensor after shifting to the switching processing, the reference sensor can be removed after the switching processing is started. Therefore, when replacing the reference sensor with a new switching destination sensor, it is possible to shorten the time until the replacement is completed by the switching time.

Second Embodiment
FIG. 6 is a block diagram schematically showing the configuration of a temperature indicator according to a second embodiment of the present invention. The same reference numerals are used for the same configuration as that of the first embodiment (FIG. 1), and the description here will be omitted or simplified.

The temperature display meter 600 of the second embodiment is obtained by adding a display unit 610 and a measurement target 620 to the first embodiment.
The display unit 610 includes an LED display unit, displays the PV value input from the switching processing unit 110, and displays the temperature of the measurement target 620 to the user.
Note that the display unit 610 may be configured by any device capable of displaying the value of PV, such as a liquid crystal panel.

  The processing in the switching processing unit 110 is the same as that of the first embodiment and thus will be omitted.

  According to the temperature display meter 600 of the second embodiment, even when temperature measurement is performed by switching a plurality of sensors, it is possible to present to the user a measured value with a sudden change reduced.

Although the switching processing unit 110 in the present embodiment is configured to set in advance the switching time, the switching time is calculated based on the deviation between PV2 and PV1 when PV1 exceeds a predetermined value. It may be configured as follows.
For example, when the deviation amount is small, even if the sensor is switched without setting the switching time, it is considered that sudden change of the measured value is unlikely to occur, so the switching time is set to be short. On the other hand, when the deviation amount is large, the switching time is set to be long.

The switching processing unit 110 in the present embodiment is described on the assumption of sensor switching processing at the time of temperature rise of the control target 130, but may be configured to be used at temperature lowering. That is, the switching processing unit 110 may be configured to execute the sensor switching process when the PV1 decreases and exceeds the predetermined value, ie, falls below the predetermined value.
Further, although the number of sensors is two in this embodiment, it may be three or more. In that case, a sensor to be used is set for each range of PV, and a predetermined value is set for each boundary. The switching processing unit 110 executes switching processing based on the above settings, and when the switching processing is completed, sets the sensor that was the switching destination in the switching processing to the reference sensor.
In addition, the operation cycle of the temperature controller 100 in the present embodiment is an arbitrary cycle such as 50 ms, and may be set in advance, or is configured to be set by an input unit (not shown) or the like. It may be
In addition, the predetermined value in switching processing unit 110 may be set in advance, or may be input by an input unit (not shown) or the like, and is appropriately determined according to the temperature characteristics of the sensor, etc. Just do it.
Moreover, although the temperature controller 100 in this Embodiment is applied with respect to the sensor comprised with the thermocouple, it is applicable with respect to arbitrary sensors, such as a resistance temperature detector.
Moreover, although the output part 120 in this embodiment is comprised so that PID calculation may be performed, you may be comprised so that arbitrary control calculations may be used.
In addition, in the calculation of the correction measurement value, the elapsed time may be measured by an external device and acquired by the temperature measurement device 150.

  Each configuration in each of the above-described embodiments may be configured as hardware by a dedicated circuit or the like, or may be implemented as software on a general-purpose circuit such as a microcomputer. Good.

100 Temperature controller 110 Switch processing unit 120 Output unit 130 Control object 141, 142 Sensor 150 Temperature measurement device 600 Temperature indicator 610 Display unit 620 Measurement object PV, PV1, PV2 Measured value PVadj ... Correction measurement value MV ... Output value

Claims (6)

Among the sensor inputs that measure the temperature of the same measurement object, the sensor input used for the measurement from the reference input that is the input from the reference sensor that is the measurement reference to the switching destination input that is the input from the switching destination sensor And a switching processing unit for switching
The switching processing unit
When the value of the reference input does not exceed the predetermined value, the value of the reference input is output as the measurement value of the measurement target,
When the value of the reference input exceeds the predetermined value and the elapsed time from the time when the predetermined value is exceeded is less than a predetermined switching time, the point at the time when the reference input exceeds the predetermined value A corrected measurement value corrected based on the deviation amount between the value of the switching destination input and the value of the reference input is calculated, and the corrected measurement value is output as the measurement value of the measurement target,
When the value of the reference input exceeds the predetermined value and the elapsed time since the point exceeds the predetermined value is equal to or longer than the switching time, the value of the switching destination input is the measured value of the measurement target Output as
A temperature measuring device characterized by   The switching processing unit is proportional to the switching time based on the switching time and a deviation between the value of the switching destination input and the value of the reference input when the reference input exceeds the predetermined value. The temperature measurement device according to claim 1, wherein the correction measurement value is calculated by performing correction. The temperature measurement device according to claim 1, wherein the switching processing unit calculates the correction measurement value according to the following equation.

PVadj is the correction measurement value, Z is the value of the switching destination input, E is the deviation between the value of the switching destination input and the value of the reference input when the predetermined value is exceeded, Y is the switching time, T Represents an elapsed time from the time when the predetermined value is exceeded.   The temperature measurement device according to any one of claims 1 to 3, wherein the switching processing unit determines the switching time based on the deviation amount when the predetermined value is exceeded.   A temperature indicator, comprising: the temperature measurement device according to any one of claims 1 to 4; and a display unit for displaying an output from the temperature measurement device. A temperature measuring device according to any one of claims 1 to 5, or a temperature indicator.
A calculation unit that calculates a control signal for controlling the temperature of the measurement target to the target temperature based on the output from the temperature measurement device and the target temperature;
An output unit that outputs the control signal to the measurement target directly or through another device;
A temperature controller characterized by comprising.

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