JPS63191935A - Temperature sensor - Google Patents

Abstract

PURPOSE:To correct a deviation in the output voltage of a temperature detecting circuit due to a secular change and to accurately measure temperature by selecting an input from a reference resistance by an input switching means and adjusting the deviation of the output voltage of the temperature detecting circuit automatically by an arithmetic part and an output adjusting means. CONSTITUTION:A temperature detecting element 1 and the reference resistance 2 are connected to the input switching means 3 and switched under the command of an arithmetic part 4. When measurement is performed normally, the resistance value of the element 1 is converted by a temperature detecting circuit 5 into a voltage signal, which is outputted from a terminal 6. When the output voltage of the circuit 5 is adjusted, the means 3 is switched to the side of the resistance 2, whose voltage signal is inputted to the arithmetic part 4 and compared with the input voltage of the element 1. Then if the voltage signal deviates owing to the secular change, an output adjusting means 7 makes a fine adjustment automatically under the command of the arithmetic part 4. Consequently, invariably correct temperature measurement is performed even in long-period use.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a temperature sensor used in various air conditioners.

Conventionally, in this type of temperature sensor, as shown in FIG. 3, a temperature detection element 101 inputs a resistance value corresponding to a temperature change of the object to be measured to a temperature detection circuit 102, and a voltage corresponding to the resistance value is inputted to a temperature detection circuit 102. converted into a signal. And temperature detection circuit 1
For 02, a predetermined power supply voltage was supplied from the power supply circuit 103. With the above configuration, the voltage corresponding to the measured temperature generated in the temperature detection circuit 102 is sent to the outside through the external connection terminal 104. Problems to be Solved by the Invention In such a conventional configuration, when the characteristics of various elements in the temperature detection circuit 102 change due to aging etc., the output voltage may deviate. However, there was a problem in that a voltage equivalent to the measured temperature could not be obtained.

The present invention solves these problems, and aims to provide a temperature sensor that can obtain a voltage equivalent to the measured temperature even when the characteristics of various elements in the temperature detection circuit 102 change due to aging or the like. This is the purpose.

Means for Solving the Problem In order to solve this problem, the present invention provides a temperature detection element whose resistance value changes as the temperature of the object to be measured changes, and a temperature detection element that always exhibits a constant resistance value regardless of temperature changes. An input switching means for switching the input of either the reference resistance and the temperature detection element or the reference resistance; a temperature detection circuit that generates a voltage corresponding to the resistance value from the resistance value selected by the input switching means; A temperature sensor consisting of a calculation unit that issues a command to the output adjustment means that finely adjusts the output voltage when the signal is input, and automatically adjusts the voltage input from the temperature detection circuit to the reference resistance value. The structure is as follows.

Operation According to the above configuration, during long-term use, the input switching means periodically selects the input from the reference resistor, and at that time,
By determining the voltage generated in the temperature detection circuit in the calculation section, if a deviation occurs in the output voltage due to aging, etc., the calculation section issues a command to the output adjustment means to finely adjust the output voltage. It will be done automatically.

EXAMPLE An example of the present invention will be described below with reference to FIGS. 1 and 2. In Fig. 1, 1 is a temperature detection element that shows a resistance value according to the measured temperature as the temperature of the object to be measured changes, and together with a reference resistor 2 that always shows a constant resistance value regardless of temperature changes. It is connected to the input switching means 3. Here, the input switching means 3 selects either the temperature detection element 1 or the reference resistor 2 according to a command from the calculation section 40, and inputs the selected resistance value to the temperature detection circuit 6. Then, this temperature detection circuit 6 converts it into a voltage signal corresponding to the resistance value. Next, this voltage signal is output as it is to the outside through the connection terminal 6 via the arithmetic unit 4 when performing normal measurement, that is, inputting the resistance value from the temperature detection element 1. Reference numeral 7 denotes an output adjustment means, which has a function of automatically adjusting the output voltage based on a command from the calculation unit 4 when adjusting the output voltage of the temperature detection circuit 5 using the p1 reference resistor 2. The circuit 8 includes input switching means 3, arithmetic unit 4, and temperature detection circuit 5, respectively.
The configuration is such that a predetermined power supply voltage is supplied. According to the above configuration, when the output voltage of the temperature detection circuit 5 is adjusted periodically, for example
Once a day, a command is issued to the input switching means 3 for a certain period of time to switch the input, that is, to switch from the temperature detection element 1 to the reference resistance 2. Therefore, input switching means 3
The reference resistor 2 is selected, and this is converted into a voltage signal in the temperature detection circuit 6.

Next, the voltage signal is input to the arithmetic unit 4, where it is automatically determined whether or not the input voltage deviates from the voltage corresponding to the reference resistor 2.

If it is determined that the characteristics of various elements in the temperature detection circuit 6 have changed due to changes over time, etc., and a deviation has occurred in the input voltage, the arithmetic unit 4 changes the υ output adjustment means 7. A command is issued to adjust the input voltage so that it becomes equivalent to the reference resistance 2.

In this way, the calculation section 4 repeatedly issues a command to the output adjustment means 7 while feeding back the voltage input from the temperature detection circuit 5, thereby correcting deviations in the output voltage caused by aging. Correct within a certain amount of time.

Furthermore, after a certain period of time, the calculation unit 4 again instructs the input switching means 3 to switch to the input from the temperature detection element 1,
Normal temperature measurements will be taken.

FIG. 2 is a graphical representation of the judgment criteria used when the calculation section 4 adjusts the output voltage to the output voltage adjustment means 7. The horizontal axis 201 represents the resistance value input to the temperature detection circuit 5, and the vertical axis 202 represents the voltage output from the temperature detection circuit 5. Now, if the resistance value of the reference resistor 2 is X(Q-203), then the output voltage Y(
v) Judgment is made based on −204.

Now, if the output voltage when the reference resistor 2 is inputted is Y + Δα (v) - 205 due to aging etc., the calculation means 4 instructs the output adjustment means 7 to lower the output voltage. issue instructions to. Similarly, Y−Δβ(v) −20
If it is e, a command is issued to increase the output voltage.

In the manner described above, the deviation in the output voltage caused by aging or the like is corrected by the calculating section 4.

Effects of the Invention As is clear from the above description of the embodiments, according to the present invention, deviations in the output voltage of the temperature detection circuit caused by aging of the element, etc. can be corrected by the arithmetic unit and the output adjustment means. Since the temperature is automatically adjusted, it is possible to always measure the correct temperature without maintenance even during long-term use.

[Brief explanation of the drawing]

Fig. 1 is an internal configuration block diagram of a temperature sensor according to an embodiment of the present invention, Fig. 2 is an explanatory diagram showing how the output voltage of the same temperature sensor is adjusted, and Fig. 3 is an internal configuration block diagram of a conventional temperature sensor. It is a diagram. DESCRIPTION OF SYMBOLS 1... Temperature detection element, 2... Reference resistance, 3... Input switching means, 4... Arithmetic unit, 5... Temperature Detection circuit, 7...Output adjustment means. 1-5 Hirohiro and Hiro-shi double shift - test force confirmation decision 2nd figure 3rd figure

Claims (1)

[Claims] A temperature detection element whose resistance value changes as the temperature of the object to be measured changes, a reference resistor which always shows a constant resistance value regardless of temperature changes, and input switching between the temperature detection element or the reference resistance. an input switching means, a temperature detection circuit that generates a voltage corresponding to the resistance value from the resistance value selected by the input switching means, and finely adjusting the output voltage when a signal from the reference resistor is inputted. A temperature sensor consisting of a calculation unit that issues a command to the output adjustment means and automatically adjusts the voltage input from the temperature detection circuit to a value equivalent to the reference resistance.