JPH0516644A - Temperature measuring apparatus - Google Patents

Abstract

PURPOSE:To provide a temperature measuring apparatus having the function of correcting temperature rises due to solar radiation. CONSTITUTION:A junction 27 is connected to the input port PO of CPU 23 via a resistance 25. The junction 27 is connected to one end of a thermistor 9 via a resistance 29. The other end of the thermistor 9 is grounded. The junction 27 is connected to one end of a resistance 31 the other end of which is grounded, and is also connected to source voltage Vcc via a resistance 33. A photodiode 11 is connected in parallel to the resistance 33. The transmission factor of the filter of the photodiode 11 is adjusted so that the voltage rise of the photodiode 11 is equal to the voltage drop of the thermistor 9 caused when sunlight is incident while temperature is within an actual service temperature region (20-30 deg.C).

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a temperature measuring device for measuring the true ambient temperature by removing the influence of solar radiation.

[0002]

2. Description of the Related Art Conventionally, a temperature sensor is attached to an automatic air conditioner for a vehicle, and its operation is controlled so that the temperature inside the vehicle detected by the temperature sensor becomes a set temperature. There is.

The temperature sensor is attached to the front panel or ceiling of the vehicle, and it is said that the points that truly represent human warmth are the face and the vicinity of the upper body. Therefore, it is desirable to control the air conditioner by arranging a temperature sensor on the seat top or headrest of a vehicle close to the human face or upper body.

[0004]

However, there is a problem that the temperature measured by the temperature sensor becomes higher than the ambient temperature because the upper portion of the seat, the headrest or the like is the place where the sun rays directly hit.

An object of the present invention is to provide a temperature measuring device having a function of correcting a temperature rise due to solar radiation.

[0006]

In order to achieve the above object, the present invention is a temperature measuring device having a function of correcting the temperature rise due to the amount of solar radiation, which detects the ambient temperature and responds to high and low temperatures. Temperature measuring means for outputting a temperature signal,
A solar radiation measuring unit which is arranged in the vicinity of the temperature measuring unit and outputs a solar radiation signal corresponding to the amount of solar radiation incident on the periphery of the temperature measuring unit from the outside, and the solar radiation included in the temperature signal based on the solar radiation signal. The gist is a temperature measuring device characterized in that the temperature measuring device is provided with a correcting means for removing a temperature rise component due to.

[0007]

According to the present invention, since the temperature rising component due to the solar radiation included in the temperature signal measured by the temperature measuring means is removed based on the solar radiation signal of the solar radiation measuring means, the true temperature not affected by the solar radiation is obtained. Can be measured.

[0008]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 2 is an explanatory diagram showing a schematic configuration of the temperature measuring device according to the first embodiment of the present invention. In FIG. 2, the temperature measuring device 1 is attached to a headrest 3 provided inside a vehicle compartment.

The temperature measuring device 1 is provided with a case 7 having a louver 5 on its side surface and a case 7 arranged inside the case 7 to detect the ambient temperature and output a temperature signal corresponding to the temperature level. It has a thermistor 9, a photodiode 11 as an insolation measuring unit which is arranged on the outer surface of the case 7 and outputs an insolation signal corresponding to the amount of insolation, and a filter 13 attached to the front surface of the photodiode 11. Phototransistor or Cd as means for measuring solar radiation
You may use the photoconductive element which consists of S cells.

FIG. 1 is a circuit diagram showing a circuit configuration of the temperature measuring device shown in FIG. In FIG. 1, a temperature measuring device 1
Is connected to the air conditioner controller (hereinafter,
A CPU 23 is provided in the controller 21). A connection point 27 is connected to the input port P0 of the CPU 23 via the resistor 25. The connection point 27 is connected to one end of the thermistor 9 via a resistor 29. Thermistor 9
The other end of is grounded. The connection point 27 is connected to the other end of the resistor 31 whose one end is grounded, and also has the resistor 33.
Is connected to the power supply voltage Vcc via. The photodiode 11 is connected in parallel with the resistor 33.

The connection point 35 between the thermistor 9 and the resistor 29 is connected to the other end of a capacitor 37 whose one end is grounded. As the thermistor 9, for example, an NTC thermistor having a negative temperature coefficient of resistance and a resistance of about 5 KΩ at 25 ° C. is used.
For example, when light of 100 lux is incident,
A device that outputs a current of 10 mA to 20 mA is used.

The resistance 25 is about 30 KΩ, the resistance 29 is about 100 Ω, the resistance 31 is about 1.5 KΩ, and the resistance 33 is
Of about 2 KΩ are used. The resistor 25 and the capacitor 37 are used to protect the input of the CPU 23, and the resistors 29, 31 and 33 are used to adjust the input voltage to the input port P0 to a predetermined level.

Next, the operation of the circuit shown in FIG. 1 will be described.
If the effect of the photodiode 11 is not taken into consideration, the resistance of the thermistor 9 will decrease and the current flowing through the thermistor 9 will increase when the temperature rises due to solar radiation.
Voltage drops. On the other hand, due to solar radiation, a current corresponding to the amount of solar radiation flows through the photodiode 11, and the voltage at the connection point 27 increases according to the intensity of solar radiation.

Here, by adjusting the transmittance of the filter 13, the voltage of the photodiode 11 rises with respect to the voltage drop of the thermistor 9 when the solar radiation is applied in the actual use temperature range (20 ° C. to 30 ° C.). Are equal. Then, the effect of decreasing the voltage of the thermistor 9 due to the solar radiation and the effect of increasing the voltage of the photodiode 11 are offset, and the output voltage corresponding to the true ambient temperature is input to the input port P0 of the CPU 23.

As a result, the true temperature around the head can be detected regardless of solar radiation. As described above, according to the present embodiment, it is possible to measure the ambient temperature without the influence of solar radiation with a simple circuit configuration.

FIG. 3 is a circuit diagram of the second embodiment of the present invention. In FIG. 3, the controller 41 has a CPU 43.
Have. The CPU 43 has two input ports P1 and P2.
Is provided. A connection point 47 is connected to the input port P1 via a resistor 45. The connection point 47 is connected to one end of the thermistor 9 via a resistor 49. The other end of the thermistor 9 is grounded. The connection point 47 is connected to the other end of the resistor 51 whose one end is grounded, and is also connected to the power supply voltage Vcc via the resistor 53. The thermistor 9
The other end of a capacitor 57 whose one end is grounded is connected to a connection point 55 between the resistor 49 and the resistor 49.

A connection point 67 is connected to the input port P2 via a resistor 65. The connection point 67 is connected to one end of the photodiode 11 via the resistor 69. The other end of the photodiode 11 is grounded. The connection point 67 is connected to the other end of the resistor 71 whose one end is grounded, and
It is connected to the power supply voltage Vcc through the resistor 73. At the connection point 75 between the photodiode 11 and the resistor 69,
The other end of the capacitor 77 whose one end is grounded is connected.

As the thermistor 9 and the photodiode 11, the same ones as in the first embodiment are used. Resistances 45 and 65 are about 30 KΩ, resistances 49 and 69 are about 100 Ω, resistances 51 and 71 are about 1.5 KΩ, and resistance 5 is
As 3,73, those of about 2 KΩ are used. The functions of the above resistors and capacitors are the same as in the first embodiment.

Next, the operation of the circuit shown in FIG. 3 will be described.
When the temperature rises due to solar radiation, the resistance of the thermistor 9 decreases and the current flowing through the thermistor 9 increases, so the input voltage of the input port P1 decreases. The CPU 43 detects the temperature Tr of the thermistor 9 according to the value of the input voltage of the input port P1.

On the other hand, due to the solar radiation, a current corresponding to the amount of solar radiation flows through the photodiode 11 and, according to the intensity of solar radiation,
The input voltage of the input port P2 becomes high. Where the CPU
43 based on the value of the input voltage of the input port P2,
The temperature rise component Ts due to solar radiation is detected, and the temperature rise component Ts due to solar radiation measured by the photodiode 11 is subtracted from the temperature Tr measured by the thermistor 9.

Then, it is possible to detect the true temperature around the head which is not affected by solar radiation. According to the second embodiment, as in the first embodiment, it is possible to measure the ambient temperature without the influence of solar radiation with a simple circuit configuration. Further, since the outputs of the thermistor 9 and the photodiode 11 are separately input to perform the calculation, the magnitude of the output value of the photodiode to be subtracted can be easily changed by rewriting the software, and the adjustment is easy. ..

Although the embodiments have been described above, the present invention is not limited to the embodiments and can be implemented in various modes without departing from the spirit of the present invention. For example, the thermistor of the embodiment may have a positive temperature coefficient of resistance.

[Brief description of drawings]

FIG. 1 is a circuit diagram of a temperature measuring device according to a first embodiment of the present invention.

FIG. 2 is an explanatory diagram showing a schematic configuration of the temperature measuring device shown in FIG.

FIG. 3 is a circuit diagram of a second embodiment of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Temperature measuring device, 9 ... Thermistor, 11 ... Photo diode 23,43 ... CPU 25,29,31,33,45,49,51,53,6
5,69,71,73 ... Resistance

Claims (1)

Claim: What is claimed is: 1. A temperature measuring device having a function of correcting a temperature rise due to solar radiation, comprising: a temperature measuring means for detecting an ambient temperature and outputting a temperature signal corresponding to whether the temperature is high or low. A solar radiation measuring unit that is arranged in the vicinity of the temperature measuring unit and outputs a solar radiation signal corresponding to the amount of solar radiation incident on the periphery of the temperature measuring unit from the outside, and the solar radiation included in the temperature signal based on the solar radiation signal. A temperature measuring device comprising: a correction unit that removes a temperature rise component due to.