Temperature sensor abnormality determination device, temperature sensor abnormality determination method, and temperature sensor abnormality determination program

Abstract

To predict abnormality of two pairs of temperature sensors, using measurement values of the two pairs of temperature sensors.SOLUTION: A temperature sensor abnormality determination device 1, which determines abnormality of two pairs of temperature sensors A1 and A2 (B1 and B2) having two sensors measuring almost same place in an atmosphere of a measurement object integrated, comprises: a data accumulator 2 that accumulates measurement values of a plurality of latest samples every prescribed time of the two pairs of temperature sensors A1 and A2 (B1 and B2); a detector 3 that detects a differential of a difference between averages of measurement values of the two pairs of temperature sensors A1 and A2 (B1 and B2) accumulated in the data accumulator 2; and a sensor warning determinator 4 that determines presence or absence of abnormality of the two pairs of temperature sensors A1 and A2 (B1 and B2) on the basis of a detection result of the detector 3.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a temperature sensor anomaly determination device, a temperature sensor anomaly determination method, and a temperature sensor anomaly determination program for determining anomalies in a plurality of temperature sensors that measure the temperature at substantially the same location on a measurement object. [Background technology]

[0002] For example, in a heating furnace as a measurement target, temperature sensors such as thermocouples and resistance thermometers are used to control the temperature of the heater. In a heating furnace, the temperature inside the furnace is high, and the temperature sensor used to control the temperature of the heater deteriorates over time, decreasing the accuracy of the detection results, making it impossible to accurately grasp the temperature inside the furnace, and making it necessary to replace the temperature sensor.

[0003] As a method of knowing when to replace a temperature sensor, for example, the techniques disclosed in Patent Documents 1 and 2 below are known. In Patent Document 1, the resistance value is measured from the voltage drop when a current is supplied to the temperature sensor from a current source, and the time to replace the temperature sensor is predicted from the change in the measured resistance value over time, thereby informing the user when to replace the temperature sensor. In Patent Document 2, the number of excessive temperature events experienced by the temperature sensor, the duration of the excessive temperature events, the temperature between excessive temperature events, etc. are accumulated in the memory of the process variable transmitter or the memory of the temperature sensor, and the temperature sensor is monitored to inform the user when to replace the temperature sensor. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 10-232170 [Patent Document 2] Special Publication No. 2015-522160 Summary of the Invention [Problem to be solved by the invention]

[0005] However, there is a problem that a dedicated device and parameter management are required in a method that measures resistance values ​​to predict the lifespan of a temperature sensor, as in Patent Document 1. Also, there is a problem that a dedicated parameter is required to manage the temperature sensor, as in Patent Document 2, which counts the number of times the sensor is used and indicates when to replace the temperature sensor.

[0006] Therefore, the present invention has been made in consideration of the above problems, 1 pair Using the temperature sensor measurements 1 pair The object of the present invention is to provide a temperature sensor anomaly determination device, a temperature sensor anomaly determination method, and a temperature sensor anomaly determination program that can predict an anomaly in a temperature sensor. [Means for solving the problem]

[0007] In order to achieve the above object, the temperature sensor abnormality determination device according to claim 1 of the present invention is Heating furnace as Two devices measure the temperature at approximately the same location in the atmosphere. temperature The sensor is integrated A pair of things Temperature Sensor and a first control loop in which a measurement value and a set value of one of the pair of temperature sensors in one set are input to a first PID controller and a first heater is controlled on / off based on an operation amount corresponding to the difference between the measurement value and set value of one of the pair of temperature sensors in the other set is input to a second PID controller and a second control loop in which a measurement value and a set value of one of the pair of temperature sensors in the other set are input to a second PID controller and a second heater is controlled on / off based on an operation amount corresponding to the difference between the measurement value and set value of one of the pair of temperature sensors in the other set. A temperature sensor abnormality determination device for determining an abnormality of a temperature sensor, Regarding the two sets of temperature sensors, The above 1 pair Temperature sensor 1 lot of the batch processing a data accumulator for accumulating the latest multiple sample measurements for each sample; Regarding the two sets of temperature sensors, The data stored in the data storage device 1 pair a sum of squares of the sampled measurement difference from the difference between the measurement values ​​of the multiple samples of the temperature sensor and an average of the sampled measurement difference, a variance of the sampled measurement difference based on the calculated sum of squares of the sampled measurement difference and the number of sampled measurement values, a test statistic is calculated based on the calculated variance of the sampled measurement difference, the sum of squares of the sampled measurement difference and the number of sampled measurement values, and a comparison standard value based on the number of sampled measurement values ​​and a significance level is compared with the test statistic to determine 1 pair a verification device for verifying whether the measured values ​​of the temperature sensors are different; Regarding the two sets of temperature sensors,Based on the test result of the tester, 1 pair and a sensor warning determiner for determining whether or not there is an abnormality in the temperature sensor.

[0008] Claims of the invention 2 The temperature sensor abnormality determination method described in Heating furnace as Two devices measure the temperature at approximately the same location in the atmosphere. temperature The sensor is integrated A pair of things Temperature Sensor and a first control loop in which a measurement value and a set value of one of the pair of temperature sensors in one set are input to a first PID controller and a first heater is controlled on / off based on an operation amount corresponding to the difference between the measurement value and set value of one of the pair of temperature sensors in the other set is input to a second PID controller and a second control loop in which a measurement value and a set value of one of the pair of temperature sensors in the other set are input to a second PID controller and a second heater is controlled on / off based on an operation amount corresponding to the difference between the measurement value and set value of one of the pair of temperature sensors in the other set. A temperature sensor anomaly determination method using a temperature sensor anomaly determination device for determining an anomaly of a temperature sensor, Regarding the two sets of temperature sensors, The temperature sensor abnormality determination device includes a data storage device. 1 pair Temperature sensor 1 lot of the batch processing storing the most recent multiple sample measurements for each; Regarding the two sets of temperature sensors, The temperature sensor abnormality determination device includes a verification device that detects the abnormality of the temperature sensor. 1 pair a sum of squares of the sampled measurement difference from the difference between the measurement values ​​of the multiple samples of the temperature sensor and an average of the sampled measurement difference, a variance of the sampled measurement difference based on the calculated sum of squares of the sampled measurement difference and the number of sampled measurement values, a test statistic is calculated based on the calculated variance of the sampled measurement difference, the sum of squares of the sampled measurement difference and the number of sampled measurement values, and a comparison standard value based on the number of sampled measurement values ​​and a significance level is compared with the test statistic to determine 1 pair testing whether the measurements of the temperature sensors are different; Regarding the two sets of temperature sensors, A sensor warning determination unit provided in the temperature sensor abnormality determination device determines whether or not the temperature sensor abnormality is detected based on the inspection result of the inspection unit. 1 pair and determining whether or not there is an abnormality in the temperature sensor.

[0009] Claims of the invention 3 The temperature sensor abnormality judgment program described in Heating furnace as Two devices measure the temperature at approximately the same location in the atmosphere. temperatureThe sensor is integrated A pair of things Temperature Sensor and a first control loop in which a measurement value and a set value of one of the pair of temperature sensors in one set are input to a first PID controller and a first heater is controlled on / off based on an operation amount corresponding to the difference between the measurement value and set value of one of the pair of temperature sensors in the other set is input to a second PID controller and a second control loop in which a measurement value and a set value of one of the pair of temperature sensors in the other set are input to a second PID controller and a second heater is controlled on / off based on an operation amount corresponding to the difference between the measurement value and set value of one of the pair of temperature sensors in the other set. A temperature sensor anomaly determination program for determining an anomaly of a temperature sensor, Computer, Regarding the two sets of temperature sensors, The above 1 pair Temperature sensor 1 lot of the batch processing a data accumulator for accumulating the latest multiple sample measurements for each sample; Regarding the two sets of temperature sensors, The data stored in the data storage device 1 pair a sum of squares of the sampled measurement difference from the difference between the measurement values ​​of the multiple samples of the temperature sensor and an average of the sampled measurement difference, a variance of the sampled measurement difference based on the calculated sum of squares of the sampled measurement difference and the number of sampled measurement values, a test statistic is calculated based on the calculated variance of the sampled measurement difference, the sum of squares of the sampled measurement difference and the number of sampled measurement values, and a comparison standard value based on the number of sampled measurement values ​​and a significance level is compared with the test statistic to determine 1 pair a verification device for verifying whether the measured values ​​of the temperature sensors are different; Regarding the two sets of temperature sensors, Based on the test result of the tester, 1 pair The present invention is characterized in that the temperature sensor is made to function as a sensor warning determiner for determining whether or not there is an abnormality in the temperature sensor. Effect of the Invention

[0010] According to the present invention, there is no need for dedicated devices or parameter management as in the past. 1 pair Using the most recent temperature sensor readings 1 pair It is possible to predict abnormalities in the temperature sensor. [Brief description of the drawings]

[0011] [Figure 1] 1 is a block diagram of a temperature sensor abnormality determination device according to the present invention; [Diagram 2] 1 is a diagram showing an example of a measurement system in which a temperature sensor abnormality determination device according to the present invention is adopted; DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

[0013] First, a measurement system in which the present invention is adopted will be described with reference to Fig. 2. As shown in Fig. 2, measurement system 11 comprises a vacuum heat treatment furnace (heating furnace) 12 as a measurement object and two control loops 13.

[0014] The inside of the vacuum heat treatment furnace 12 is maintained in a vacuum state by a vacuum pump 14, and heaters 15 (15A, 15B) are arranged in the upper and lower parts of the furnace, respectively.

[0015] In addition, in the vicinity of each heater 15 (15A, 15B), 1 pair Temperature sensors A1 and A2 1 pair In the example of FIG. 2, the temperature sensors B1 and B2 are arranged near the heater 15A at the top of the furnace. 1 pair Temperature sensors A1 and A2 are arranged. 1 pair The temperature sensors A1 and A2 are constructed as two temperature sensors inserted into one tube. 1 pair Temperature sensors B1 and B2 are arranged. 1 pair The temperature sensors B1 and B2 are 1 pair Similar to the temperature sensors A1 and A2, the temperature sensor 10 is configured as an integrated unit in which two temperature sensors are inserted into one pipe.

[0016] In this embodiment, 1 pair Temperature sensors A1 and A2 1 pair Although a thermocouple in which an electromotive force increases with a change in the internal resistance is used as the temperature sensors B1 and B2, the present invention is not limited to this, and for example, a resistance temperature detector or the like can also be used.

[0017] The two control loops 13 consist of an upper control loop 13A and a lower control loop 13B.

[0018] The upper control loop 13A and the lower control loop 13B are each configured with a PID controller 13a and an SCR (thyristor) 13b to control the temperature inside the vacuum heat treatment furnace 12 to a target temperature so that the temperature distribution inside the furnace for each lot of batch processing is approximately uniform, for example.

[0019] In the upper control loop 13A, 1 pair The measurement value (temperature data) of one of the temperature sensors A1, A2 and the upper furnace temperature set value are input to the PID controller 13a, and the PID controller 13a outputs an operation amount (0 to 100%) corresponding to the difference between them to the SCR 13b for drive control, and the SCR 13b controls the heater 15A on / off.

[0020] Similarly, in the lower control loop 13B, 1 pair The measurement value of one of the temperature sensors B1, B2 and the lower furnace temperature set value are input to the PID controller 13a, and the PID controller 13a outputs an operation amount (0 to 100%) corresponding to the difference between the two to the SCR 13b for drive control, and the SCR 13b controls the on / off of the heater 15B.

[0021] The temperature sensor abnormality determination device of this embodiment is the above-mentioned measurement system 11. 1 pair Temperature sensors A1, A2 ( 1 pair By examining the difference in the mean difference (test of difference in paired data) between temperature sensors B1 and B2, 1 pair Temperature sensors A1, A2 ( 1 pair It has the function of judging abnormalities in the temperature sensors B1, B2 and alerting the operator.

[0022] As shown in FIG. 1, the temperature sensor anomaly determination device 1 comprises a data accumulator 2, a verification device 3, and a sensor warning determiner 4 in order to realize the above functions.

[0023] The data storage device 2 is composed of a memory for storing data, 1 pair Temperature sensors A1 and A2 1 pair The most recent 10 sample measurements (temperature data) from temperature sensors B1 and B2 are always stored as reference samples. 1 pairSave the data for each temperature sensor A1, A2, B1, and B2.

[0024] The measured values ​​stored in the data accumulator 2 are 1 pair The measured values ​​of the temperature sensors A1 and A2 for each batch processing lot (predetermined time), 1 pair These are the measured values ​​for each lot (predetermined time) of the batch processing of the temperature sensors B1 and B2. The number of reference samples stored in the data accumulator 2 is not limited to the measured values ​​of 10 samples, and can be changed as appropriate.

[0025] Tester 3 is used to test the difference between paired data. 1 pair Temperature sensors A1, A2 ( 1 pair The difference between the average values ​​of the measured values ​​of the temperature sensors B1 and B2 (which are the same if normal) is examined according to the following steps 1 to 4. 1 pair Temperature sensors A1 and A2 1 pair The case of the temperature sensors B1 and B2 will be described as an example.

[0026] Step 1: Set the null hypothesis H0 and alternative hypothesis H1 The null hypothesis is H0:δ=0. The alternative hypothesis is set as follows depending on the value of the variable iTestMode: iTestMode=0… H1:δ≠0 iTestMode=1… H1:δ>0 iTestMode=2… H1:δ<0

[0027] Here, δ is 1 pair The difference between temperature sensors A1 and A2 or 1 pair is the difference between the temperature sensors B1 and B2.

[0028] The significance level α depends on the value of the variable iILevel, as follows: iILevel=0… α=0.05 iILevel=1… α=0.10 iILevel=2… α=0.20

[0029] Step 2: Calculate the test statistic t0 1 pair Temperature sensor A1, A2 or 1 pair When the average value of the samples of δ and the variance of the samples of δ are calculated from the difference between the temperature sensors B1 and B2 using the following formulas (1) and (2), the test statistic t0 is expressed by the following formula (3). Here, the number of samples n is set to 10.

[0030]

number

[0031]

number

[0032]

number

[0033] Step 3: Testing The null hypothesis H0 is tested using the test statistic t0 for the t-test, where t(n-1,α) is the comparison standard value obtained from the t-test table, and α is the significance level (usually 0.05).

[0034] If H1:δ≠0, then |t0|≧t(n-1,α) is significant and H0 is rejected. In other words, H1 is judged to be correct. If H1:δ>0, then if t0≧t(n-1,2α), it is significant and H0 is rejected. In other words, H1 is judged to be correct. If H1:δ<0, then if t0≦t(n-1,2α), it is significant and H0 is rejected. In other words, H1 is judged to be correct.

[0035] In any case, if H0 is rejected, 1 pair Temperature sensors A1, A2 or 1 pair This means that there is a difference between the temperature sensors B1 and B2. 1 pair Temperature sensor A1, A2 or 1 pairIt is determined that temperature sensors B1 and B2 are faulty.

[0036] The rejection region based on the number of groups k is as shown in Table 1 below.

[0037] [Table 1]

[0038] The verification device 3 performs the above-mentioned verification. 1 pair Temperature sensor A1, A2 or 1 pair If it is determined that the average values ​​of the temperature sensors B1 and B2 are the same, it outputs a test result signal of "0". 1 pair Temperature sensor A1, A2 or 1 pair If it is determined that the averages of the measured values ​​of the temperature sensors B1 and B2 are different, it outputs a test result signal of "1."

[0039] When the test result signal "1" is input from the tester 3, the sensor warning determiner 4: 1 pair Temperature sensor A1, A2 or 1 pair The measured values ​​of the temperature sensors B1 and B2 are different, it is determined that there is an abnormality, and a warning is given to the operator by, for example, sound or display.

[0040] next, 1 pair Temperature sensors A1 and A2 1 pair An example of the test using specific measured values ​​of the temperature sensors B1 and B2 will be described.

[0041] Now, lot by lot 1 pair Temperature sensors A1 and A2 1 pair Assume that the measured values ​​of the temperature sensors B1 and B2 are as shown in Table 2 below.

[0042] [Table 2]

[0043] first, 1 pair The temperature sensors A1 and A2 are inspected.

[0044] 1 pair When the difference between the temperature sensors A1 and A2 is calculated, the result is shown in Table 3 below.

[0045] [Table 3]

[0046] 1 pair The average value is calculated from the difference between the temperature sensors A1 and A2, the variance is calculated from equation (1), and the test statistic t0 is calculated from equation (3), resulting in the following equations (4), (5), (6), and (7).

[0047]

number

[0048]

number

[0049]

number

[0050]

number

[0051] And, t0=4.621>t(9,0.05)=2.262 is significant. 1 pair The measured values ​​of the temperature sensors A1 and A2 are different, that is, it can be determined that either the temperature sensor A1 or the temperature sensor A2 is abnormal.

[0052] Similarly, 1 pair The temperature sensors B1 and B2 are inspected.

[0053] 1 pair The difference between the temperature sensors B1 and B2 is calculated as shown in Table 4 below.

[0054]

Table 4

[0055] 1 pair Calculate the average value from the difference between the temperature sensors B1 and B2, calculate the variance from Equation (1), and calculate the test statistic t0 from Equation (3), then it becomes as shown in the following Equations (8), (9), (10), and (11).

[0056]

Equation

[0057]

Equation

[0058]

Equation

[0059]

Equation

[0060] And, since t0 = 0.753 < t(9,0.05) = 2.262, it is not significant, 1 pair it cannot be said that the measured values of the temperature sensors B1 and B2 are different, that is, it can be determined that neither of the temperature sensors B1 and B2 is abnormal.

[0061] By the way, in the above-described embodiment, the case where the temperature inside the vacuum heat treatment furnace 12 in the measurement system 11 is 1 pair detected by the temperature sensors A1 and A2 and 1 pair the temperature sensors B1 and B2 has been described as an example, but the measurement system and 1 pair the number of temperature sensors are not limited.

[0062] In addition, in the above-described embodiment, the components of the temperature sensor abnormality judgment device 1 (the data accumulator 2, the verification device 3, and the sensor warning judgment device 4) may be configured as a computer equipped with an arithmetic processing device, a memory device, etc., and the processing of each component may be executed by a program.

[0063] In this way, according to the above-described embodiment, it is possible to predict an abnormality in a temperature sensor using the most recent measurement value output by the temperature sensor itself, without the need for dedicated devices or parameter management as in the conventional art.

[0064] Although the best mode of the temperature sensor anomaly determination device, the temperature sensor anomaly determination method, and the temperature sensor anomaly determination program according to the present invention has been described above, the present invention is not limited by the description and drawings according to the mode. In other words, all other modes, embodiments, and operation techniques made by those skilled in the art based on the mode are naturally included in the scope of the present invention. [Explanation of symbols]

[0065] 1 Temperature sensor abnormality detection device 2 Data Accumulator 3. Tester 4 Sensor warning judgement device 11 Measurement System 12 Vacuum heat treatment furnace 13 Control Loop 13A 1st Zone Upper Control Loop 13B Second Zone Upper Control Loop 13a PID controller 13b SCR (thyristor) 14 Vacuum Pump 15(15A,15B) Heater A1, A2, B1, B2 1 pair Temperature Sensor

Claims

1. a temperature sensor anomaly detection device for detecting an anomaly of the temperature sensor in a measurement system that controls the heating furnace to a target temperature so that the temperature distribution in the furnace for each lot of batch processing is approximately uniform, the temperature sensor anomaly detection device comprising: two sets of temperature sensors, each set consisting of two integrated temperature sensors that measure temperatures at approximately the same location in the atmosphere of a heating furnace as a measurement target; a first control loop in which a measurement value and a set value of one of the pair of temperature sensors in one set are input to a first PID controller and a first heater is controlled on / off based on an operation amount corresponding to the difference between the measurement value and set value of one of the pair of temperature sensors in one set, and a second control loop in which a measurement value and a set value of one of the pair of temperature sensors in the other set are input to a second PID controller and a second heater is controlled on / off based on an operation amount corresponding to the difference between the measurement value and set value of one of the pair of temperature sensors in the other set, the temperature sensor anomaly detection device detecting an anomaly of the temperature sensor in a measurement system that controls the heating furnace to a target temperature so that the temperature distribution in the furnace for each lot of batch processing is approximately uniform, the temperature sensor anomaly detection device comprising: a data storage unit that stores the latest multiple sample measurements of the pair of temperature sensors for each lot of the batch processing for the two sets of temperature sensors; a tester for calculating a sum of squares of the sampled measurement difference from the difference between the multiple samples of the pair of temperature sensors stored in the data storage device and an average of the sampled measurement difference, for the two sets of temperature sensors, calculating a variance of the sampled measurement difference based on the calculated sum of squares of the sampled measurement difference and the number of sampled measurement values, calculating a test statistic based on the calculated variance of the sampled measurement difference, the sum of squares of the sampled measurement difference and the number of sampled measurement values, and testing whether the measured values ​​of the pair of temperature sensors are different by comparing the test statistic with a comparison reference value based on the number of sampled measurement values ​​and a significance level; a sensor warning determiner for determining whether or not the pair of temperature sensors is abnormal based on the inspection result of the inspector for the two sets of temperature sensors.

2. a temperature sensor anomaly detection method using a temperature sensor anomaly detection device that detects anomalies in the temperature sensors in a measurement system that controls the heating furnace to a target temperature so that the temperature distribution in the furnace for each lot in a batch process is approximately uniform, the method comprising: using two sets of temperature sensors, each set of temperature sensors being an integrated pair of temperature sensors that measure temperatures at approximately the same location in the atmosphere of a heating furnace as a measurement target; a first control loop in which a measurement value and a set value of one of the pair of temperature sensors in one set are input to a first PID controller and a first heater is controlled on / off based on an operation amount corresponding to the difference between the measurement value and set value of one of the pair of temperature sensors in one set, and a second control loop in which a measurement value and a set value of one of the pair of temperature sensors in the other set are input to a second PID controller and a second heater is controlled on / off based on an operation amount corresponding to the difference between the measurement value and set value of one of the pair of temperature sensors in the other set, A step of storing the latest measured values ​​of a plurality of samples of the pair of temperature sensors for each lot of the batch processing by a data storage device provided in the temperature sensor abnormality determination device for the two sets of temperature sensors; a step of calculating, by a verification device provided in the temperature sensor anomaly determination device for the two sets of temperature sensors, a sum of squares of the sampled measurement value differences from the difference between the measurement values ​​of the multiple samples of the pair of temperature sensors stored in the data storage device and an average of the sampled measurement value differences, calculating a variance of the sampled measurement value differences based on the calculated sum of squares of the sampled measurement value differences and the number of sampled measurement values, calculating a test statistic based on the calculated variance of the sampled measurement value differences, the sum of squares of the sampled measurement value differences and the number of sampled measurement values, and verifying whether the measurement values ​​of the pair of temperature sensors are different by comparing the test statistic with a comparison reference value based on the number of sampled measurement values ​​and a significance level; A temperature sensor abnormality determination method comprising: a step of determining whether or not the pair of temperature sensors is abnormal based on the inspection results of the inspection device using a sensor warning determination device provided in the temperature sensor abnormality determination device.

3. a temperature sensor anomaly determination program for determining an anomaly of the temperature sensor in a measurement system that controls the heating furnace to a target temperature so that the temperature distribution in the furnace for each lot of batch processing is approximately uniform, the temperature sensor anomaly determination program comprising: two sets of temperature sensors, each set of temperature sensors being an integrated pair of temperature sensors that measure temperatures at approximately the same location in the atmosphere of a heating furnace as a measurement target; a first control loop in which a measurement value and a set value of one of the pair of temperature sensors in one set are input to a first PID controller and a first heater is controlled on / off based on an operation amount corresponding to the difference between the measurement value and set value of one of the pair of temperature sensors in one set, and a second control loop in which a measurement value and a set value of one of the pair of temperature sensors in the other set are input to a second PID controller and a second heater is controlled on / off based on an operation amount corresponding to the difference between the measurement value and set value of one of the pair of temperature sensors in the other set, Computer, a data storage unit that stores the latest multiple sample measurements of the pair of temperature sensors for each lot of the batch processing for the two sets of temperature sensors; a tester for calculating a sum of squares of the sampled measurement difference from the difference between the multiple samples of the pair of temperature sensors stored in the data storage device and an average of the sampled measurement difference, for the two sets of temperature sensors, calculating a variance of the sampled measurement difference based on the calculated sum of squares of the sampled measurement difference and the number of sampled measurement values, calculating a test statistic based on the calculated variance of the sampled measurement difference, the sum of squares of the sampled measurement difference and the number of sampled measurement values, and testing whether the measured values ​​of the pair of temperature sensors are different by comparing the test statistic with a comparison reference value based on the number of sampled measurement values ​​and a significance level; a temperature sensor abnormality determination program for causing the two sets of temperature sensors to function as a sensor warning determiner that determines whether or not the pair of temperature sensors is abnormal based on the inspection result of the inspector.

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