JPH0133771B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a temperature measuring method using a temperature measuring element such as a thermistor, a platinum temperature measuring antibody, a diode, etc. whose electrical constant changes depending on temperature sensing, and particularly to The present invention relates to a method for accurately measuring temperature by correcting variations in the temperature sensing function and errors that occur based on changes in ambient temperature conditions in the path from measurement by a thermometer to temperature display by a temperature display means.

In general, the temperature-sensing functions of thermometers such as thermistors, platinum resistance thermometers, and diodes vary widely due to manufacturing reasons, and when used for temperature measurement that requires high accuracy, temperature detectors with a certain level of accuracy are selected and used. Therefore, it is inevitable that a temperature measuring device using such a temperature measuring element will be expensive.
In addition, the electrical physical constant change value that occurs when the temperature sensing element senses the temperature, for example, the electrical resistance value corresponding to the temperature change in the case of a thermistor (this is defined as "surface temperature electrical information" in this application), In normal cases, in order to transmit the surface temperature electrical information via a transmission path to the temperature display means which is further away from the position of the temperature measuring body, a method is adopted in which the electrical temperature information is converted into electrical information for transmission suitable for transmission.
Therefore, the transmission path and information converter are affected by changes in the surrounding temperature conditions (temperature changes between cold season and summer, etc.), and the electrical information for transmission that reaches the position of the temperature display means is affected by changes in the temperature conditions. There is a disadvantage that error values are included.

SUMMARY OF THE INVENTION Therefore, in order to eliminate the above-mentioned drawbacks and inconveniences, an object of the present invention is to first convert surface temperature electrical information emitted from a thermometer into electrical information for transmission, and further convert this electrical information for transmission into a system having a temperature display means. It is an object of the present invention to provide a temperature measurement method which makes it possible to obtain an accurate temperature value by adding correction when receiving the temperature value at a receiving section and converting it into a temperature value.

The phonetic electrical information generated by the thermometer whose temperature characteristics are classified in advance into multiple types during temperature measurement is converted into electrical information for transmission by an electrical-electrical converter and transmitted to the receiving section, and The electrical-to-electrical converter forms correction electrical information of the same type as the transmission electrical information assigned in advance to the temperature characteristics of each classification category, and similarly transmits it to the receiving section, where the electrical information is stored in advance. Calculate the error due to the temperature difference between the specified temperature and the actual temperature included in the received correction electrical information from the standard correction electrical information under the specified temperature stored in the circuit, and calculate the error in the calculation result. The error amount due to the temperature difference included in the electrical information for transmission is corrected according to the number of minutes, and the electrical information for transmission is corrected from the plurality of classification categories of the temperature measuring body stored in advance in the storage circuit. Temperature measurement characterized by further correcting the error amount based on the temperature characteristics of the temperature measuring body included in the above, and converting the electrical information for transmission after both of these corrections into a temperature value and displaying it as an actual temperature measurement. A method is provided. The present invention will be described in detail below based on embodiments shown in the accompanying drawings.

The figure is a block diagram showing an example of a configuration for implementing the temperature measurement method according to the present invention.

In the figure, a temperature measuring section 1 has a temperature measuring element 4 and is a part that actually measures the internal temperature of a freezer or refrigerator. In this case, as the temperature sensing element 4, as described above, an element whose electrical physical constant changes depending on temperature sensing is used, such as a thermistor, a platinum resistance temperature sensing element, or a diode. The electrical surface temperature information sensed and generated by the temperature measuring section 1 is converted by the electrical-to-electrical converting section 2 and transmitted to the receiving section 3. In this embodiment, the temperature measuring body 4 indicates an electrical resistance value as surface temperature electrical information, and the electrical-to-electrical converter 2 converts this into a frequency and transmits it to the receiver 3. . Now, the electric-electric converter 2 is provided with an unstable multivibrator circuit 5, and the circuit 5 is connected to a capacitor 6.
It is provided to output electrical information at a frequency determined by the variable resistor 7 and electrical information at a frequency determined by the electrical resistance value of the temperature sensing element 4 and the capacitor 6. 6 and the variable resistor 7 are transmitted to the receiving section 3 to be used as correction electrical information as will be described later. The electrical information of the frequency determined by the above corresponds to electrical information for transmission, which is obtained by converting surface temperature electrical information into electrical information suitable for transmission and transmission. In addition, the above-mentioned unstable multivibrator 5
The generation of the two electrical information for transmission is sequentially transmitted to the receiving section 3 according to the switching of the contacts by the switch 8, and the timing of the switching of the contacts of the switch 8 is controlled by a switch switching timer 9. be done. Both pieces of electrical information are then transmitted to the receiving section 3 as pulse signals. Note that the capacitor 10 provided in the electrical-electrical converter 2 is provided as a ripple removal capacitor, and the resistor 1
1 is also provided as a ripple removal resistor. Furthermore, the resistor 12 is provided as a signal current adjusting resistor.

Now, the receiving section 3 includes a pulse detector 13 for receiving and detecting the above-mentioned electrical information, and a first correction calculation circuit 1.
5, second correction calculation circuit 16, temperature conversion circuit 17,
It is configured to include a correction calculation processing section 14 each having a memory circuit 18, and a temperature display section 19.

In the above-mentioned configuration, in carrying out the temperature measurement method of the present invention, first, the temperature of the temperature measuring element 4 exhibiting under a certain temperature condition (for example, a temperature of 25° C. for a thermistor) is measured. Resistance value widths based on manufacturing variations are classified into a plurality of classification categories, and any temperature measuring element 4 is made to belong to any classification category. In other words, for example, thermometer A is classified as category 1.
In addition, it is determined at the manufacturing stage of the temperature measuring device that the temperature measuring device B belongs to classification 2 and the temperature measuring device C belongs to classification 3. In this case, the non-stable multivibrator circuit 5 is used for each classification of resistance value under the above-mentioned constant temperature condition (for example, 25
Appropriately assign the frequency of the correction electrical information generated at 30°F (°C), and use a variable resistor so that the electrical information of the assigned frequency (in this case, a pulse train having the assigned number of pulses in a 1-second period) is generated. 7 and the electrical constants of capacitor 6 are set. At this time, a relatively large frequency difference is provided between the frequencies assigned corresponding to each classification so that the frequencies are discrete values. Thus, now classification category 1
When temperature measurement is carried out using temperature measuring element A belonging to class A, the variable resistor 7 is adjusted so that the pulse train of the frequency assigned to classification section 1 is generated from the unstable multivibrator circuit 5. Therefore, when using the B thermometer belonging to classification 2, the variable resistor 7 is newly adjusted to generate a pulse train of the frequency assigned to classification 2.

In this way, when actually measuring the temperature of the object to be measured using temperature measuring element A as the temperature measuring element 4,
The temperature measuring body 4 is provided within the object to be temperature measured and constantly generates an electrical resistance value that changes according to temperature changes as surface temperature electrical information. During this time, when the switch 8 is switched to the contact on the variable resistor 7 side, the unstable multivibrator circuit 5 generates a pulse train with a frequency determined in advance by the resistance value of the variable resistor 7 and the capacitance value of the capacitor 6. However, the frequency of the pulse train actually generated differs greatly depending on the ambient temperature conditions, for example, in a cold period of winter and a period of extreme heat in summer. It shows a frequency value that includes an error due to a change in temperature conditions that differs from the actual case. The pulse train generated from the unstable multivibrator circuit 5 in this manner is detected by the pulse detector 13 of the receiving section 3. When the frequency of the pulse train detected by this pulse detector 13 is ₁ , ₁ = ₀ + △ ₁ (1). Here ₀ is a constant temperature condition (e.g.
The frequency of the pulse train, which is electrical information for correction, is assigned at 25°C), and △ ₁ is the frequency error due to deviation from the constant temperature condition due to changes in ambient temperature conditions. The pulse detector 13 sends the detected electrical information of frequency ₁ to the first correction calculation circuit 15, compares it with the electrical information of assigned frequency ₀ stored in the storage circuit 18 in advance, and calculates the temperature error △ ₁ and the error rate. Performs the calculation △ ₁ / ₀ . At this time, the memory circuit 18 contains not only the electrical information of the assigned frequency ₀ , but also
Other electrical information with frequencies assigned under constant temperature conditions corresponding to other classification categories is also stored, but as mentioned above, each frequency of this electrical information has a relatively large frequency difference. Since they are assigned as mutually discrete values, the pulse detector 1
3 detects electrical information with frequency ₁ , the first correction calculation circuit 15 can easily determine that the frequency of the corresponding reference electrical information is ₀ , and therefore △ ₁ , △ You can also easily obtain the calculation result _{of 1/0} . During this time, the switch 8 is switched to the contact on the temperature measuring element 4 side in the electrical-electrical converter 2, so that the surface temperature electrical information of the temperature measuring element 4 becomes unstable. (pulse train) and similarly transmitted to the pulse detecting section 13 of the receiving section 3. The pulse detector 13 detects the number of pulses, that is, the frequency, of this electrical information for transmission. If this frequency is ₂ ,
This electrical information for transmission includes the constant temperature at which the thermometer 4 is classified (for example, 25 degrees Celsius as mentioned above) and the temperature of the object to be measured, which naturally differs because the installation location is different. This includes an error of △ ₂ due to the influence of changes in the ambient temperature conditions of the electric-to-electric converter 2. Therefore, ₂ = F ₂ + △ ₂ ...(2). Here, F ₂ is a frequency corresponding to the temperature of the object to be measured whose temperature is sensed by the temperature measuring element 4 .

The pulse detector 13 sends the detected electrical information of frequency ₂ to the first correction calculation circuit 15 again. Here, regarding the error due to changes in the ambient temperature conditions of the electrical-to-electrical converter 2, in the case of the correction electrical information, since the common unstable multivibrator circuit 5 is used, the correction electrical information It shows the same error tendency as the error in the case of .

Therefore, the relationship △ ₁ / ₀ ≒ △ ₂ /F ₂ ...(3) holds true. From formula (3) above, △ ₂ ≒F ₂ ×△ ₁ / ₀ ... (4) Therefore, from formulas (2) and (4), ₂ = F ₂ +F ₂ ×△ ₁ / ₀ ≒F ₂ (1 + △ ₁ / ₀ ), therefore, F ₂ = ₂ / 1 + Δf ₁ /f ₀ ...(5) holds true.

Therefore, by using the value of △ ₁ / ₀ previously calculated in the first correction calculation circuit 15, F ₂ can be obtained from equation (5).
can be calculated. The F ₂ calculated in this way is sent from the first correction calculation circuit 15 to the second correction calculation circuit 16, and here the temperature characteristic of the temperature measuring element 4 stored in advance in the storage circuit 18, that is, the temperature characteristic of the temperature measuring element 4 By reading the nonlinear characteristics between the temperature and surface temperature electrical information from the storage circuit 18 into the second correction calculation circuit 16, the above-mentioned frequency can be further adjusted.
Correct _F2 . The electrical information of the corrected frequency F′ ₂ obtained in this way is the electrical information of the final corrected frequency. In other words, the nonlinear characteristics are corrected to linear characteristics. Such a frequency
The electrical information of F′ ₂ is sent from the second correction calculation circuit 16 to the temperature conversion circuit 17, and the comparison information between the frequency and temperature regarding the temperature measuring body 4, which has been stored in the storage circuit 18 in advance, is read into the temperature conversion circuit 17. At above frequency
A temperature value corresponding to the electrical information of F' is obtained and the temperature is displayed on the temperature display section 19.

As is clear from the above description, according to the present invention, when measuring temperature using a thermometer, the measurement error based on the temperature characteristics of the thermometer itself and the surface temperature information measured by the thermometer The measurement accuracy is high because both the measurement error and the measurement error mixed in due to changes in the temperature conditions of the surrounding environment are corrected during the time when the temperature is displayed by the temperature display means through various transmission paths near and far. A temperature measurement method with high performance has been realized, and unlike the conventional method of using only a small number of thermometers through selection, all thermometers can be classified and divided according to their performance. It is also possible to obtain cost reduction effects.

Note that the above embodiment was explained based on the case where the surface temperature electrical information of the temperature measuring body is an electrical resistance value, and the electrical information for transmission and the electrical information for correction are pulse train information from an unstable multivibrator. However, it should be understood that it is possible to implement the temperature measurement method using the two correction operations according to the present invention even if other electrical and physical constants are used.

[Brief explanation of drawings]

The figure is a block diagram showing a configuration example for implementing the temperature measurement method according to the present invention. 1...Temperature measurement section, 2...Electrical-electrical conversion section, 3...
...Receiving section, 4...Temperature measuring body.

Claims (1)

[Claims] 1. A thermometer whose temperature characteristics at the time of temperature measurement are classified in advance into a plurality of types.
The electrical conversion section converts the electrical information into transmission electrical information and transmits it to the receiving section, and the electrical-electrical conversion section also generates correction electrical information of the same type as the electrical transmission information that has been assigned in advance to the temperature characteristics of each classification category. Information is formed and transmitted to the receiving section, and the receiving section calculates the specified temperature included in the received correction electrical information from the standard correction electrical information under the specified temperature stored in advance in the storage circuit. and the actual temperature, and correct the error due to the temperature difference contained in the electrical information for transmission according to the error of the calculation result, and From the plurality of stored classification categories of the temperature measuring body, an error based on the temperature characteristics of the temperature measuring body included in the transmission electrical information is further corrected, and the transmitting electricity is obtained by correcting both of these corrections. A temperature measurement method characterized by converting information into a temperature value and displaying it as an actual temperature. 2. The electrical-to-electrical conversion unit alternately and continuously transmits the electrical information for transmission and the electrical information for correction to the receiving unit at a constant timing, and displays information on the display unit based on the electrical information for transmission and the electrical information for correction. 2. The temperature measuring method according to claim 1, wherein the corrected transmission electrical information is displayed continuously.