CN118500583A - Calibration method of electronic temperature measuring device - Google Patents

Abstract

The invention is suitable for the technical field of temperature measurement, and provides a calibration method of an electronic temperature measuring device, wherein the electronic temperature measuring device comprises a main board and a temperature sensor, and the calibration method comprises the following steps: acquiring a resistance value difference between the actual running resistance value of the main board and a standard resistance value; performing primary resistance compensation on the main board according to the resistance value; acquiring the resistance deviation value of the actual measured resistance value of the temperature sensor at the standard temperature of the required calibration point and the preset standard resistance of the temperature point; and carrying out secondary resistance compensation on the temperature sensor according to the resistance deviation value. According to the invention, the main board and the temperature sensor are respectively subjected to secondary calibration in a resistance value calibration mode, so that the error of the resistance value to the temperature can be greatly eliminated, the temperature measurement precision is greatly improved, the same main board can be used as an independent calibration universal board after being calibrated, the mass production of products is facilitated, and the production efficiency is improved.

Description

Calibration method of electronic temperature measuring device

Technical Field

The invention belongs to the technical field of temperature measurement, and particularly relates to a calibration method of an electronic temperature measuring device.

Background

The existing electronic temperature measuring device of electron has deviation with the actual temperature because of product self, therefore, in order to accurately display the actual measured temperature, it is necessary to calibrate the temperature deviation of the electronic temperature measuring device before the electronic temperature measuring device leaves the factory so that the final displayed temperature is close to the actual temperature.

The electronic temperature measuring device is characterized in that the temperature value obtained by the system is displayed again according to the temperature value obtained by the resistance temperature relation table, namely the resistance value actually consists of two parts of the resistance of the main board and the resistance value of the temperature sensor. In the prior art, the calibration is usually performed on the temperature sensor, that is, only the temperature measured by the resistance value of the portion of the temperature sensor is calibrated, but in practical application, the main board of the electronic temperature measuring device is an integrated circuit composed of a plurality of electronic components, in the working circuit of the electronic temperature measuring device, each electronic component has an allowable error range on a nominal value, when the circuit is operated, the integrated circuit composed of a plurality of electronic components can cause different voltage value changes, in the singlechip system, the final system is used for judging that the final value of the obtained resistance is obtained by converting the received voltage, and for this reason, when the actual operating resistance of the main board has a deviation value from the theoretical standard resistance, in the operating temperature measuring program, the deviation value is accumulated to the resistance corresponding to the final measured temperature, so that the finally displayed temperature generates a dimensional deviation, and the temperature measuring precision is low. In addition, since the resistance value between each temperature sensor is different, and the actual running resistance value of each main board is different, the average temperature deviation compensation mode is given to the temperature measuring device in batches, and each device cannot accurately obtain the compensation value. And because the temperature of the finished product of the device is increased to reach the temperature of the calibration point for a long time, the temperature of the monomer cannot be increased to reach the temperature of the calibration point in production, and then compensation is independently given.

Disclosure of Invention

The invention provides a calibration method of an electronic temperature measuring device, which aims to solve the problems of low temperature measurement precision and low calibration efficiency of the electronic temperature measuring device in the prior art.

The invention is realized in such a way that an electronic temperature measuring device comprises a main board and a temperature sensor, and the calibration method comprises the following steps:

acquiring a resistance value difference between the actual running resistance value of the main board and a standard resistance value;

performing primary resistance compensation on the main board according to the resistance value difference;

acquiring the resistance deviation value of the actual measured resistance value of the temperature sensor at the standard temperature of the required calibration point and the preset standard resistance value at the standard temperature of the required calibration point;

and carrying out secondary resistance compensation on the temperature sensor according to the resistance deviation value.

Further, the step of obtaining the difference between the actual running resistance value of the main board and the standard resistance value includes:

externally hanging a standard resistor on a main board to obtain an actual running resistance value of the standard resistor;

And calculating a resistance value difference between the actual operation resistance value and the standard resistance value according to the actual operation resistance value and the standard resistance value of the standard resistance.

Further, the resistance of the plug-in resistor is a preset resistance corresponding to the standard temperature of the required calibration point.

Further, the step of performing the primary resistance compensation on the motherboard according to the resistance difference includes:

If the value of the resistance value difference is smaller than or equal to 0, adding the value of the resistance value difference;

And if the value of the resistance value difference is larger than 0, subtracting the value of the resistance value difference.

Further, the step of obtaining the resistance deviation value of the actual measured resistance value of the temperature sensor at the standard temperature of the required calibration point and the preset standard resistance at the standard temperature of the required calibration point includes:

acquiring an actual measured resistance value of the temperature sensor at a standard temperature of a required calibration point;

And calculating a resistance deviation value between the actual measured resistance at the standard temperature of the required calibration point and the preset resistance standard value at the standard temperature of the required calibration point according to the actual measured resistance at the standard temperature of the required calibration point and the preset resistance standard value at the standard temperature of the required calibration point, wherein the resistance deviation value = the preset resistance standard value-the actual measured resistance value.

Further, the step of performing secondary resistance compensation on the temperature sensor according to the resistance deviation value includes:

And acquiring an actual resistance value of the temperature sensor in actual temperature measurement, and calculating a compensated resistance value according to the actual resistance value in the actual temperature measurement and the resistance deviation value, wherein the compensated resistance value=the actual resistance value in the actual temperature measurement+the resistance deviation value.

Further, the step of compensating the secondary resistance value of the temperature sensor according to the resistance deviation value further comprises:

And matching the compensated resistance value with a preset resistance standard value on a resistance temperature relation table, and displaying the temperature corresponding to the preset resistance standard value closest to the compensated resistance value.

Further, the calibration method further comprises:

And uniformly setting the resistance values of the temperature sensors with the same B value at different temperatures to form a resistance temperature relation table corresponding to the resistance values and the temperatures, wherein the resistance temperature relation table is stored in the main board system and is used for correspondingly taking in the measuring process.

The invention has the beneficial effects that the calibration of the electronic temperature measuring device is divided into two parts for calibration, namely, the main board and the temperature sensor are calibrated separately, the influence on temperature measurement caused by the deviation of the actual resistance value and the standard resistance value of the main board and the temperature sensor can be eliminated simultaneously, compared with the traditional calibration method which calibrates the temperature sensor only, the scheme eliminates the influence on the whole temperature measurement operation program of the resistance value of the main board, therefore, the temperature measurement precision of the electronic temperature measurement device is improved, in addition, the temperature sensor is calibrated in a resistance compensation mode before the temperature measurement, compared with the traditional mode of directly compensating the temperature on the temperature after the temperature is acquired, the temperature measurement precision of the electronic temperature measurement device can be further improved by adopting the design scheme, and the resistance deviation generated between the temperature and resistance conversion can be reduced; in addition, the purpose that each temperature measuring device finished product is independently calibrated is achieved by measuring and compensating each main board in advance, measuring the resistance value of each temperature sensor at the temperature calibration point in advance, obtaining the resistance value required to be compensated and recording the resistance value, and the temperature sensor is extremely short in time when the temperature sensor is not assembled into the finished product and is more suitable for actual production and independent calibration.

Drawings

FIG. 1 is a flow chart of a method for calibrating an electronic temperature measuring device provided by the invention;

FIG. 2 is a partial calibration flow chart of a motherboard of a calibration method of an electronic temperature measurement device according to the present invention;

FIG. 3 is a flowchart of another calibration of a motherboard of an electronic temperature measurement device calibration method according to the present invention;

FIG. 4 is a flow chart of calibration of a temperature sensor of a calibration method of an electronic temperature measuring device according to the present invention;

Fig. 5 is a table of reference of the resistance characteristics and temperature relationship of the NTC temperature sensor provided by the present invention.

Detailed Description

The present invention will be described in further detail with reference to the drawings and examples, in order to make the objects, technical solutions and advantages of the present invention more apparent. It should be understood that the specific embodiments described herein are for purposes of illustration only and are not intended to limit the scope of the invention.

Referring to fig. 1, an embodiment of the present invention provides a calibration method for an electronic temperature measuring device, where the electronic temperature measuring device includes a motherboard and a temperature sensor, and the calibration method includes the following steps:

a1: acquiring a resistance value difference between an actual running resistance value of the main board and a standard resistance value;

a2: performing primary resistance compensation on the main board according to the resistance value difference;

The steps A1 and A2 are calibrated aiming at the resistance value of the main board, so that the actual running resistance value can reach the standard resistance value after compensation, and the resistance value of the main board is relatively reset to zero, wherein the zero is not the actual resistance value of 0, but means that the accuracy of the final resistance value is influenced by the fact that the actual running resistance after compensation is matched with the standard resistance and the zero is the same as the following zero so as to prevent the resistance value difference existing in the main board from accumulating into the resistance value in the final temperature measurement program.

B1: acquiring the resistance deviation value of an actual measured resistance value of a temperature sensor at the standard temperature of a required calibration point and a preset standard resistance value at the standard temperature of the required calibration point;

B2: and carrying out secondary resistance compensation on the temperature sensor according to the resistance deviation value.

And B1 and B2 are calibrated for the temperature sensor, and the resistance value of the temperature sensor is calibrated at the standard temperature before the temperature sensor is converted into the temperature, so that the actual measured resistance value of the temperature sensor at the standard temperature is equal to the preset standard resistance value, and the obtained resistance can approach to the standard resistance value corresponding to the temperature in the actual temperature measurement, thereby eliminating the influence on the temperature display caused by the resistance value deviation of the temperature sensor due to the B value (namely the difference of material constants) at the source.

The embodiment of the invention divides the calibration of the electronic temperature measuring device into two parts for calibration, namely, separately calibrating the main board and the temperature sensor, can simultaneously eliminate the influence on temperature measurement caused by the deviation of the actual resistance value and the standard resistance value of the main board and the temperature sensor, and compared with the traditional calibration method which only calibrates the temperature sensor, the scheme eliminates the influence of the resistance value of the main board on the whole temperature measurement operation program, therefore, the temperature measurement precision of the electronic temperature measurement device is improved, in addition, the temperature sensor is calibrated in a resistance compensation mode before temperature measurement, compared with the traditional mode of directly compensating the temperature at the temperature after the temperature is obtained, the temperature measurement precision of the electronic temperature measurement device can be further improved by adopting the design scheme, and the resistance deviation generated between the temperature and resistance conversion can be reduced. In addition, the purpose that each temperature measuring device finished product is independently calibrated is achieved by measuring and compensating each main board in advance, measuring the resistance value of each temperature sensor at the temperature calibration point in advance, obtaining the resistance value required to be compensated and recording the resistance value, and the temperature sensor is extremely short in time when the temperature sensor is not assembled into the finished product and is more suitable for actual production and independent calibration.

According to the calibration method for the electronic temperature measuring device, provided by the embodiment of the invention, the main board and the temperature sensor are respectively calibrated in a resistance value calibration mode, so that the error of the resistance value to the temperature can be greatly eliminated, the temperature measuring precision is greatly improved, the same main board can be used as an independent calibration universal board after being calibrated, the mass production of products is facilitated, and the production efficiency is improved.

It should be noted that the "primary" and "secondary" are merely illustrative of the number of times of compensation to the electronic temperature measuring device, and are not represented as a limitation of the sequence of the two times of compensation.

In particular, in order to better understand the difference between the temperature compensation adopted by the temperature sensor in the embodiment of the present invention and the temperature compensation adopted by the prior art, the advantages of the temperature compensation and the resistance compensation adopted by the present invention are better understood, and the detailed description is given below.

Taking NTC temperature sensors adopted in body thermometers as an example, the conventional compensation method is to measure the current resistance value of the temperature sensor in a constant temperature tank with a calibration temperature of 37 ℃, see fig. 5, fig. 5 is a table (referred to as RT characteristic table) of resistance values of temperature sensors in different temperature ranges of one batch, and because the temperature sensors in different production batches have differences in B values (material constants of the temperature sensors) due to the characteristics of the temperature sensors, and the B values of the temperature sensors in each batch are different, the resistance value compensation of each batch is to determine the B value of the batch and then to derive a new RT characteristic table according to the B value, and the temperature sensors in the same batch are subjected to temperature calibration and measurement based on the RT characteristic table, so the embodiment of the invention is illustrated by taking one RT table as an example. For ease of understanding, some of the parameters from the tables will be chosen as illustrations. Assuming that the current resistance value obtained in the 37 ℃ constant temperature tank is 60804 ohms (for the sake of easy understanding, one of the limit values in the corresponding resistance value range at the temperature is directly taken as an illustration, and the actual temperature at the 37 ℃ constant temperature tank is taken for calculation in actual temperature measurement), the standard temperature of the required calibration point is 37 ℃, and referring to fig. 5, the resistance value of the temperature sensor at 37 ℃ is between 58992 ohms and 60808 ohms, and the temperature sensor belongs to a qualified product. When the resistance value measured in the constant temperature bath at 37 ℃ is 60804 ohms, the closest resistance value of the resistance value in the electronic temperature relation table is 60887 ohms, the program considers that the current temperature measurement is 36.6 ℃, and the measured temperature is 36.6 ℃ and the calibration temperature is different by 0.4 ℃ because of the error of 0.4 ℃, therefore, before the factory leaves the factory for the electronic thermometer, the compensation coefficient of 0.4 ℃ is input to the host of the electronic temperature measuring device, namely, in the temperature measuring process, the temperature result host obtained after each temperature measurement is added with the temperature compensation of 0.4 ℃ and then is displayed as the final temperature system. This calibration method using temperature compensation has the following drawbacks:

(1) The temperature measurement error is large, and the error is inevitably at least above 0.1 ℃.

First, the measured resistance value in the 37-degree thermostat bath has a resistance difference from the standard resistance value. For example, the measured resistor 60804 ohm, which is different from the standard resistor 60887 ohm corresponding to 36.6 ℃ by 83 ohm, is shown 36.6 ℃ as long as the difference from the standard resistor 60887 ohm is within 125 ohm (because the difference is larger than 125 ohm, the measured resistor is closer to the standard resistor 60637 ohm corresponding to 36.7 ℃) due to the free resistance property, and the host recognizes that the temperature corresponding to a preset standard value closest to the measured resistor is the measured temperature, namely, determines that the temperature of the measured resistor 60804 ohm is 36.6 ℃. However, the measured resistance 60804 ohm is actually different from the standard resistance 60887 ohm by 83 ohm, and thus, the measured resistance is directly converted into temperature after being obtained, so that the difference between the measured resistance and the standard resistance is within 0.05 ℃, and the temperature within 0.05 ℃ is the initial error generated when the temperature sensor is calibrated at the standard temperature of the required calibration point.

Second, since there is a certain difference between the measured resistance value at the standard temperature of the required calibration point and the standard resistance value at the standard temperature of the required calibration point when the calibration is performed, there is also a certain difference between the measured resistance value and the standard resistance value at the measured temperature when the thermometer is used for actual temperature measurement, and the measured resistance value is shifted between the two standard resistance values, when the resistance difference is greater than half of the difference between the two standard resistance values, a deviation error is generated to display the corresponding temperature, and thus an error of 0.1 ℃ is generated.

(2) The final temperature display of the electronic thermometer is abnormal.

As can be seen from the above calibration method of temperature compensation, when initial calibration is performed, the measured temperature and the calibration temperature have a large difference, so that a temperature compensation coefficient with a large span is generated (for example, the above-mentioned compensation coefficient with a temperature higher than 0.4 ℃ or lower than 0.4 ℃ is generated, and this is exemplified by 0.4 ℃) is required to obtain a temperature result corresponding to the measured resistance value first and then compensate, and then the measured resistance value may exceed the lowest temperature or the highest temperature of the resistance value corresponding to the resistance temperature relation table, which may cause the host to fail to obtain a temperature result corresponding to the measured resistance value, so that the electronic temperature measuring device may display an abnormal problem. For example, when the compensation coefficient is 0.4 ℃, the temperature measurement range of the temperature measurement device commonly used by the human body is usually 34 ℃ to 43 ℃, that is, the range of the electronic temperature relation table stored in the electronic temperature measurement device is also 34 ℃ to 43 ℃, when the final temperature of the electronic temperature measurement device after compensation needs to be displayed as 34 ℃, if the compensation coefficient of the electronic side temperature device is +0.4 ℃ (i.e. when calibrated at the standard temperature of the required calibration point, the measured temperature is smaller than the specified temperature, and the compensated temperature coefficient needs to be added), at this time, the temperature corresponding to the resistance value acquired by the actual temperature sensing head should be 33.6 ℃, and the measured temperature cannot be acquired by the host computer, thereby affecting the operation of the subsequent temperature compensation program, and further causing abnormal display; similarly, when the final display temperature of the electronic temperature measuring device is 43 ℃, if the compensation coefficient of the electronic temperature measuring device is-0.4 ℃ (i.e. when calibrated at a specified temperature, the measured temperature is greater than the specified temperature, and the compensated temperature coefficient needs to be subtracted), then the temperature corresponding to the resistance value obtained by the actual temperature sensing head should be 43.4 ℃, and the corresponding resistance value at 43.4 ℃ is beyond the range of the resistance temperature relation table stored by the electronic temperature measuring device, so that the host cannot obtain the measured temperature to influence the operation of the subsequent temperature compensation program, thereby causing abnormal display.

Moreover, when the temperature sensor is calibrated in a temperature compensation mode, the temperature sensor is required to be placed in the constant temperature tank in a whole product mode after being mounted on the host, the process is equivalent to actual temperature measurement, namely, the temperature of an object to be measured needs to be measured is measured through a metal cap of the electronic temperature measuring device, a heat conducting medium is filled between the metal cap and the temperature sensor, and then the heat conducting medium is transferred to the temperature sensor, and the process needs to wait for a certain time, so that the temperature compensation calibration mode is long in time consumption, and the production efficiency is extremely low.

The embodiment of the invention compensates the resistance value difference, and compensates the generated resistance value deviation of the temperature sensor at the standard temperature (in the constant temperature tank at 37 ℃) in advance before converting the temperature difference into the temperature, eliminates the resistance value error to a certain extent at other temperatures except the standard temperature of the required calibration point, so that the final measured temperature is the resistance value corresponding to the most real temperature, and can reduce the compensation error and improve the temperature measurement precision.

Referring to fig. 2, further, step A1 of obtaining a resistance difference between an actual running resistance value of the motherboard and a standard resistance value includes:

A11: the standard resistor is hung on the main board to obtain the actual running resistance value of the standard resistor, for example, one resistor of 100K, 75K and 50K … … is selected to be connected to the main board, and the system directly converts the received voltage into the resistance value, so that the resistance value is the actual running resistance value of the hanging resistor in the main board.

The above-mentioned values of the external resistor are only for illustration and are not limited to the listed resistors, and the external resistor may be any other resistor meeting the required resistance value in addition to the listed resistances of one hundred and ten.

The resistance value of the plug-in resistor may be a preset resistance value corresponding to the standard temperature of the required calibration point, that is, the resistance value at 37 ℃ in the current batch of temperature sensors may be selected, where the resistance value at 37 ℃ refers to the intermediate resistance value at 37 ℃ in the RT characteristic table determined by the current batch of temperature sensors, for example, the intermediate resistance value 59894 Ω at 37 ℃ in fig. 5, that is, the standard resistance value of the plug-in resistor is 59894 Ω. The resistance value of the external resistor is selected to be the corresponding resistance value at 37 ℃, so that the requirement of calibrating the electronic temperature measuring device at 37 ℃ in the international standard is met, and the temperature corresponding to the resistance value of the external resistor adopted in the calibration of the main board is kept consistent with the standard temperature adopted in the calibration of the temperature sensor, so that the actual error can be greatly reduced.

A12: and calculating the resistance value difference between the actual running resistance value and the standard resistance value according to the actual running resistance value and the standard resistance value of the standard resistance, namely matching and calculating the actual running resistance value of the plug-in resistor and the standard resistance value of the plug-in resistor, wherein the difference is the resistance difference between the actual running resistance value and the standard resistance value of the plug-in standard resistance.

The actual running resistance value of the plug-in resistor on the main board is obtained through plug-in standard resistor running with known resistance value on the main board, the actual running resistance can be obtained through calculating the voltage of the main board by software and converting the voltage into the resistance, the actual running resistance value and the standard resistance value are compared, so that corresponding resistance deviation can be obtained after the temperature sensor is connected into the main board, the influence of the resistance value of the main board on actual temperature measurement during subsequent temperature measurement is eliminated by firstly compensating the main board, and the temperature measurement precision of the electronic temperature measurement device is improved.

Referring to fig. 3, further, the step A2 of performing a resistance compensation on the motherboard according to the resistance difference includes:

A21: if the value of the resistance value difference is smaller than or equal to 0, adding the value of the resistance value difference;

if the value of the resistance value difference is smaller than or equal to 0, the actual running resistance of the plug-in resistor is smaller than or equal to the standard resistance value, and the value of the resistance value difference is added at the moment, so that the resistance value of the main board can be reset to zero relatively.

A22: and if the value of the resistance value difference is larger than 0, subtracting the value of the resistance value difference.

If the value of the resistance value difference is greater than 0, the actual running resistance of the plug-in resistor is greater than the standard resistance, and the value of the resistance value difference is subtracted at the moment, so that the resistance value of the main board can be reset to zero relatively.

By executing the step A21 or the step A22, the obtained value of the resistance value difference can be compensated into a temperature measuring program, so that the influence of the resistance value of the main board on the resistance value of the temperature sensor can be eliminated, the deviation of the final temperature of the temperature measurement is avoided, and the temperature measuring precision of the electronic temperature measuring device is improved.

Referring to fig. 4, further, step B1 of obtaining a resistance deviation value of the measured resistance value of the temperature sensor at the standard temperature of the required calibration point and the preset standard resistance at the standard temperature of the required calibration point includes:

b11: acquiring an actual measured resistance value of the temperature sensor at a standard temperature of a required calibration point;

The calibration temperature is set according to an actual scene, for example, according to the temperature attribute of the object to be measured, the calibration temperature can be calibrated by selecting an intermediate value of the object to be measured in a measurement temperature range as a zero point deviation correction of the temperature sensor, the intermediate value is not an absolute intermediate value, a temperature is selected near the intermediate value as the calibration temperature, the object to be measured can include, but is not limited to, a human body, an animal outside the human body, an environmental temperature and the like, the temperature measurement range refers to a temperature measurement range of the application scene of the temperature sensor, and for example, the human body thermometer can measure the temperature of the human body between 34 ℃ and 43 ℃. For convenience of explanation, the object to be measured in this embodiment is a human body, and the normal temperature range of the human body is 36.3 ℃ to 37.2 ℃, so that any one temperature point in the range can be selected for initial point correction, and in the industry in this field, 37 ℃ is usually selected as initial point correction, so that the invention also selects 37 ℃ as initial point correction.

Specifically, the current actual measured resistance of the temperature sensor is obtained in a constant temperature tank at 37 ℃, and the standard temperature of the required calibration point is obtained at 37 ℃.

B12: and calculating a resistance deviation value between the actual measured resistance value at the standard temperature of the required calibration point and the preset resistance standard value at the standard temperature of the required calibration point according to the actual measured resistance value at the standard temperature of the required calibration point and the preset resistance standard value at the standard temperature of the required calibration point, wherein the resistance deviation value = the preset resistance standard value-the actual measured resistance value at the standard temperature of the required calibration point.

Referring to fig. 5, the preset resistance standard value is a resistance standard value set by the standard at different temperatures, for example, a central value (CENTER) in fig. 5, and the preset resistance standard value at the standard temperature of the required calibration point refers to a resistance standard value at 37 ℃, for example, a resistance standard value at 37 ℃ in fig. 5 is 59894 ohms, however, the standard resistance value at 37 ℃ can also be other set values according to different B value characteristics, and is not limited herein. However, for ease of understanding, the preset resistance standard values described herein are illustrated by reference to the center of fig. 5. In fig. 5, the lower limit value (MIN) and the upper limit value (MAX) are the minimum resistance value and the maximum resistance value of the different temperature sensors at the same temperature compared with the standard, and in the incoming material inspection, the temperature sensors within the resistance value range are all qualified samples, and the temperature sensor that obtains the actual measured resistance value at the standard temperature of the required calibration point in the step B11 is the to-be-measured product compared with the standard.

In the step, the actual measured resistance value of the temperature sensor at the standard temperature of the required calibration point is compared with the preset resistance standard value at the standard temperature of the required calibration point, so that the resistance deviation value of the actual measured resistance value of the temperature sensor at the standard temperature of the required calibration point and the preset resistance standard value is obtained, and the resistance deviation value is used as the resistance compensation coefficient of the subsequent calibration step.

In this embodiment, taking the preset resistance standard value of the temperature sensor at 37 ℃ as an example, if the preset resistance standard value is 59894 ohms, the actual measured resistance value of the temperature sensor at the standard temperature of the required calibration point obtained in the step B11 is between 58992 ohms and 60804 ohms, if the actual measured resistance value of the temperature sensor at 37 ℃ of the constant temperature tank is 60804 ohms, which is greater than the preset resistance standard value 59894 ohms, the actual measured resistance value 60804 ohms needs to be compensated for-910 ohms to be equal to the preset resistance standard value 59894 ohms, that is, in the actual temperature measurement process, the actual resistance value of the resistor at any temperature is greater than the preset resistance standard value, and the resistance difference between the actual resistance value and the preset resistance standard value is not fixed at 910 ohms because the resistance change at different temperatures is nonlinear, but the actual resistance difference is not great than 910 ohms, and the compensation coefficient can only be fixed at 910 ohms, which can be used as the resistance compensation coefficient of the temperature sensor, and the resistance difference between the actual resistance value and the preset resistance value after the compensation coefficient is extremely small.

It should be noted that, in this embodiment, when the resistance deviation value is used as the compensation coefficient and is input into the host computer of the electronic temperature measuring device, the resistance deviation value has positive and negative properties, when the actual measured resistance value is greater than the preset resistance standard value, the resistance deviation value is negative, and when the actual measured resistance value is less than the preset resistance standard value, the resistance deviation value is positive, i.e. the resistance deviation value of 910 ohms is labeled as-910 ohms.

Referring to fig. 4, the step B2 of performing secondary resistance compensation on the temperature sensor according to the resistance deviation value includes:

b21: acquiring an actual resistance value of the temperature sensor in actual temperature measurement;

B21: and calculating a compensated resistance value according to the actual resistance value and the resistance deviation value in the actual temperature measurement, wherein the compensated resistance value=the actual resistance value+the resistance deviation value.

The actual resistance value in the actual temperature measurement refers to the resistance value of the human body at the current temperature of the human body when the human body is measured, the compensated resistance value refers to the resistance value obtained by compensating the actual resistance value, and after the actual resistance value is obtained, the resistance deviation value serving as the compensation coefficient is added, and the obtained compensated resistance value tends to be closer to the preset resistance standard value corresponding to the current temperature. That is, in the measured temperature, the measured resistance value is resistance-compensated before the measured temperature is obtained (with respect to the temperature after compensation).

For example, assuming that the actual resistance value of the current temperature measurement is 65989 ohms, applying the compensation coefficient 910 ohms of the embodiment in step B12 described above, the post-compensation resistance value= 65989+ (-910) =65079 ohms.

Referring to fig. 4, further, after the temperature sensor is compensated for the second resistance value according to the resistance deviation value in step B2, specifically, in step B21, the compensated resistance value is calculated according to the actual resistance value and the resistance deviation value in the actual temperature measurement, where the compensated resistance value=the actual resistance value+the resistance deviation value further includes:

B3: and matching the compensated resistance value with a preset resistance standard value on a resistance temperature relation table, and displaying the temperature corresponding to the preset resistance standard value closest to the compensated resistance value.

The resistance temperature relation table can be obtained from the resistance characteristics and the temperature relation, the resistance temperature relation table can be stored in a host computer of the electronic temperature measuring device by executing the following step B0, the compensated resistance value obtained by the step B21 is the compensated resistance value, the compensated resistance value is the resistance value corresponding to the closest temperature, and the host computer judges that the temperature corresponding to the preset resistance standard value closest to the compensated resistance value is the current actually measured temperature by adapting the compensated resistance value to the resistance temperature relation table.

For example, when the compensated resistance value in the step B22 is 65079 ohms, according to the resistance temperature relation table (refer to fig. 5), 65079 ohms is located between 65055 ohms and 65327 ohms, 65079 ohms is different from 65327 ohms by 248 ohms and is different from 65055 ohms by 24 ohms, so that the preset resistance standard value closest to the compensated resistance value 65079 ohms is 65055 ohms, and the host computer determines that the currently measured temperature is the temperature corresponding to 65055 ohms, that is, 35 ℃.

When the traditional temperature compensation method is adopted, when the actual resistance value is 65989 ohms and the closest resistance value is 65873 ohms, the corresponding temperature is 34.7 ℃, the compensation coefficient is added to be 0.4 ℃, the final temperature is 35.1 ℃, the accuracy is 0.1 ℃ worse than that of the calibration method of the application, and the calibration method of the temperature compensation is also proved to have at least 0.1 ℃ error.

According to the above embodiment, the method for calibrating the resistance value of the temperature sensor according to the embodiment of the present invention has the following advantages compared with the conventional method for calibrating by temperature compensation:

(1) When the measured temperature is equal to the calibration temperature, the measurement result can reach zero error;

The invention directly obtains the resistance deviation value of the actual measured resistance value and the preset resistance standard value at the standard temperature of the required calibration point, takes the resistance deviation value as the resistance compensation coefficient, and returns the resistance error to zero when the measured temperature is equal to the calibration temperature in the initial calibration, so that the compensated resistance value is definitely equal to the preset resistance standard value of the current temperature when the measured temperature is equal to the calibration temperature, and the temperature measurement reaches zero error.

(2) The measurement result has high precision, no error is generated in the latter position of the decimal point in the temperature display, and meanwhile, the maximum temperature measurement error of the whole temperature measurement is not more than 0.05 ℃, and the error of the temperature measurement result is small;

The method has the advantages that zero error can be achieved when the measured temperature is higher than the calibration temperature or lower than the calibration temperature based on the measured temperature, therefore, when the measured temperature is higher than the calibration temperature or lower than the calibration temperature, the difference between the compensated resistance value compensated by the resistance value and the resistance value generated by the preset resistance standard value is extremely small relative to the resistance compensation coefficient-resistance deviation value, the difference between the compensated resistance value and the resistance value generated by the preset resistance standard value can be controlled within half of the difference between two adjacent preset resistance standard values, the resistance value comparison result is definite in direction, no wall riding value judgment exists, the temperature corresponding to the difference between the compensated resistance value and the resistance value generated by the preset resistance standard value is within 0.05 ℃, and therefore, when the temperature measurement result finally shows a decimal point later, the calibration method does not generate error, and the obtained temperature result is absolutely uniquely determined.

For example, assuming that the preset resistance standard value of the temperature sensor at 37 ℃ is 59894 ohms, with continued reference to fig. 5, when the actual measured resistance value is 58992 ohms (taking as an example the lower limit value of the range of the current temperature-corresponding resistance value of the temperature sensor at 37 ℃) is obtained in the constant temperature tank at 37 ℃, the resistance deviation value is 902 ohms, that is, the actual resistance value obtained in the actual measured temperature is also close to the lower limit value of the actual measured temperature, that is, the actual resistance value of the temperature sensor at 37 ℃ is smaller than the preset resistance standard value by 902 ohms. For convenience of explanation, this example is exemplified by the measured temperature of 39℃and by directly taking the lower limit 54325 ohms at 39 ℃. When the measured resistance value is 54325 ohms, the compensated resistance value after compensation is=54325+902=55227 ohms, the resistance value is only 26 ohms smaller than the preset resistance standard value 55201 ohms at 39 ℃, the magnitude of the 26 ohms is smaller than the difference 224 ohms between the preset resistance standard values at 38.9-39 ℃, the magnitude of the 26 ohms is also smaller than the difference 223 ohms between the preset resistance standard values at 39-39.1 ℃, the 26 ohms only account for about 10% of the 224 ohms or 223 ohms, the 26 ohms are distributed to be about equal to 0.001 ℃ at 0.1 ℃, and the error is larger than 0.05 ℃.

In addition, for the purpose of verification again, an upper limit value 60804 ohm when the actually measured resistance value of the temperature sensor in the constant temperature tank at 37 ℃ is taken as an example, at the moment, the actually measured resistance value 60804 ohm is different from a preset resistance standard value 59894 ohm by 910 ohm, and the compensation coefficient resistance deviation value is-910 because the actually measured resistance value is larger than the preset standard value. Similarly, the actual resistance value obtained at the measured temperature is also close to the upper limit value of the measured temperature. For convenience of explanation, this example is also exemplified by the measured temperature of 39℃and by directly taking the upper limit 56085 ohms at 39 ℃. When the measured resistance value is 56085 ohms, the compensated resistance value after compensation=56085-910= 55175 ohms, the resistance value is only 26 ohms smaller than the preset resistance standard value 55201 ohms at 39 ℃, the difference between the preset resistance standard values at 38.9-39 ℃ is 224 ohms, the difference between the preset resistance standard values at 39-39.1 ℃ is 223 ohms, the 26 ohms account for about 10% of the resistance value between 224 ohms or 223 ohms, the resistance value at 26 ohms is distributed to 0.1 ℃ which is about equal to 0.01 ℃, and the error is less than 0.05 ℃.

In summary, the resistance deviation value obtained at the standard temperature of the required calibration point is taken as the compensation coefficient, and the difference between the compensated resistance value obtained by adding the resistance deviation value after obtaining the actually measured resistance value and the preset resistance standard value of the current temperature is very small. Similarly, the difference between the compensated resistance value obtained by compensating the measured resistance value obtained at other measured temperatures and the preset resistance standard value of the corresponding temperature is very small, and the error is also within 0.05 ℃, which is not illustrated one by one.

It can be understood that when the difference between the compensated resistance value and the preset resistance standard value is smaller, the measurement error can be smaller when the difference is equally distributed to the step of 0.1 ℃, i.e. the measurement error is smaller when the compensated resistance value is closer to the preset resistance standard value.

(3) By adopting a permanent calibration standard value, when temperature sensors in different batches are used in the calibration method, host program software of the electronic temperature measuring device does not need to be replaced;

The temperature is determined after the resistance value is compensated before the temperature result is obtained, the resistance value belongs to a data source, the resistance value can be directly obtained and unambiguously, the preset resistance standard value can be used as a standard after the resistance value is determined, replacement is not needed, each temperature sensor also has a unique resistance value compensation coefficient, and therefore program software for executing calibration in a host can be used all the time and replacement is not needed.

(4) The final display result of the temperature will not generate abnormal display phenomenon.

The calibration method provided by the invention is that after the resistance value is compensated, the temperature result is directly confirmed according to the compensated resistance value, the measurement error is small, and the temperature displayed to the position behind the decimal point can be uniquely determined, so that the measurement result can be ensured to be in the range on the resistance temperature relation table, and the phenomenon of abnormal display caused by exceeding the range on the resistance temperature relation table is avoided.

The invention implements the calibration of the temperature sensor, can achieve absolute zero error measurement at the standard temperature of the required calibration point, has small overall measurement error of the temperature sensor and high measurement accuracy, and simultaneously has strong system operation reliability without generating abnormal display condition. In addition, compared with the traditional temperature compensation mode, the temperature sensor is calibrated without being assembled on a host machine, the temperature sensor can be directly placed in a constant temperature tank to quickly acquire the actual measured resistance value of a required calibration point and then calculate the resistance deviation value to be used as compensation data for subsequent assembled products, the conduction from a waiting metal cap to the temperature sensor and a series of calibration calculation processes are not involved, the resistance deviation value to be compensated can be quickly acquired in a short time, and the production efficiency can be greatly improved.

Referring to fig. 4, further, the calibration method further includes:

b0: and uniformly setting the resistance values of the temperature sensors with the same B value at different temperatures to form a resistance temperature relation table corresponding to the resistance values and the temperatures, wherein the resistance temperature relation table is stored in the main board system and is used for correspondingly taking in the measuring process.

The temperature sensors of different production batches have differences of B values (material constants of the temperature sensors) due to the differences in production, the B values of the temperature sensors of different batches are different, the B values of the temperature sensors of the same batch are close to the same, each batch of resistance compensation is to determine the B value of the batch and to derive a new RT characteristic table according to the B value, and temperature calibration and final temperature measurement are performed based on the RT characteristic table, so that the resistance temperature relation table can be stored in a host computer of the electronic temperature measuring device in advance for executing temperature measurement compensation operation and determining the temperature.

The foregoing description of the preferred embodiments of the invention is not intended to be limiting, but rather is intended to cover all modifications, equivalents, and alternatives falling within the spirit and principles of the invention.

Claims (8)

1. An electronic temperature measurement device calibration method, the electronic temperature measurement device including a motherboard and a temperature sensor, the calibration method comprising:

acquiring a resistance value difference between the actual running resistance value of the main board and a standard resistance value;

performing primary resistance compensation on the main board according to the resistance value difference;

acquiring the resistance deviation value of the actual measured resistance value of the temperature sensor at the standard temperature of the required calibration point and the preset standard resistance value at the standard temperature of the required calibration point;

and carrying out secondary resistance compensation on the temperature sensor according to the resistance deviation value.

2. The method for calibrating an electronic temperature measuring device according to claim 1, wherein the step of obtaining a difference between an actual running resistance value of the main board and a standard resistance value comprises:

externally hanging a standard resistor on a main board to obtain an actual running resistance value of the standard resistor;

And calculating a resistance value difference between the actual operation resistance value and the standard resistance value according to the actual operation resistance value and the standard resistance value of the standard resistance.

3. The method of calibrating an electronic temperature measuring device according to claim 2, wherein the resistance of the external resistor is a preset resistance corresponding to a standard temperature of a required calibration point.

4. The method of calibrating a resistance temperature measurement device according to claim 1, wherein the step of performing a resistance compensation on the main board according to the resistance value difference comprises:

If the value of the resistance value difference is smaller than or equal to 0, adding the value of the resistance value difference;

And if the value of the resistance value difference is larger than 0, subtracting the value of the resistance value difference.

5. The method of calibrating an electronic temperature measuring device according to claim 1, wherein the step of obtaining a resistance deviation value of an actual measured resistance value of the temperature sensor at a standard temperature of a desired calibration point and a preset standard resistance value at the standard temperature of the desired calibration point comprises:

acquiring an actual measured resistance value of the temperature sensor at a standard temperature of a required calibration point;

And calculating a resistance deviation value between the actual measured resistance at the standard temperature of the required calibration point and the preset resistance standard value at the standard temperature of the required calibration point according to the actual measured resistance at the standard temperature of the required calibration point and the preset resistance standard value at the standard temperature of the required calibration point, wherein the resistance deviation value = the preset resistance standard value-the actual measured resistance value at the standard temperature of the required calibration point.

6. The method of calibrating an electronic temperature measuring device according to claim 5, wherein the step of performing secondary resistance compensation on the temperature sensor according to the resistance deviation value comprises:

And acquiring an actual resistance value of the temperature sensor in actual temperature measurement, and calculating a compensated resistance value according to the actual resistance value in the actual temperature measurement and the resistance deviation value, wherein the compensated resistance value=the actual resistance value in the actual temperature measurement+the resistance deviation value.

7. The method of calibrating an electronic temperature measuring device according to claim 6, further comprising, after performing the secondary resistance compensation on the temperature sensor according to the resistance deviation value:

And matching the compensated resistance value with a preset resistance standard value on a resistance temperature relation table, and displaying the temperature corresponding to the preset resistance standard value closest to the compensated resistance value.

8. The method of calibrating an electronic temperature measurement device of claim 1, further comprising:

And uniformly setting the resistance values of the temperature sensors with the same B value at different temperatures to form a resistance temperature relation table corresponding to the resistance values and the temperatures, wherein the resistance temperature relation table is stored in the main board system and is used for correspondingly taking in the measuring process.