JP2000055745A - Electronic thermometer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a thermometer that can simultaneously adjust a plurality of thermally sensitive oscillators with scattering, and at the same time can perform adjustment without fixing an environmental temperature by changing the reference signal of an oscillation means and the oscillation signal of the thermally sensitive oscillator for supplying to a measurement time counter part and a counter part for measurement by switching. SOLUTION: Since a CPU 7 does not output a control signal CNT in temperature measurement, a signal switching control means 200 outputs a reference signal X and a thermally sensitive signal CRC from terminals Q1 and Q2, respectively. Also, a data selection means 103 outputs measurement time data KJD from a terminal Q. When the CPU 7 outputs a temperature measurement start signal EN, a counter part 2 for measurement time starts the counting of the reference signal X, and a counter 6 for measurement starts counting the thermally sensitive signal CRC. After that, when count data CKD of the counter part 2 for measurement time matches the measurement time data KJD, a matching circuit 4 outputs a matching signal ZF, thus enabling the counter part 2 for measurement time and the counter part 6 for measurement time to stop counting and hence completing temperature measurement.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thermometer capable of simultaneously adjusting a plurality of thermometers without considering environmental temperature and manufacturing variations of a temperature-sensitive oscillator.

[0002]

2. Description of the Related Art First, the configuration of the prior art will be described with reference to FIGS. Reference numeral 1 denotes a reference oscillation source, which includes a crystal oscillator or the like and outputs a reference signal X. Reference numeral 2 denotes a measurement time counting unit which receives the reference signal X and outputs measurement time data CK.
D is output. A count value setting unit 3 outputs fixed measurement time data SD1. Reference numeral 4 denotes a coincidence circuit which inputs the measurement time data CKD and the fixed measurement time data SD1 and outputs a coincidence signal ZF.

[0005] Reference numeral 5 denotes a temperature-sensitive oscillator, which generates a temperature-sensitive signal CRC. The detailed configuration of the temperature-sensitive oscillator 5 will be described with reference to FIG. Reference numerals 51 and 52 denote inverters (hereinafter, inverters 51 and 52 are referred to as I51 and I5).
Described as 2. ), The output of I51 is connected to the input of I52, and is also connected to one side of a thermistor 53 described later. 53 is a thermistor, and the other side is I5
1 is connected to one side of a capacitor 54 described later. A capacitor 54 is connected to the output of I52. Further, a temperature sensing signal CRC is output from the terminal CRT.

[0004] As shown in FIG. 2, reference numeral 6 denotes a counter for measurement, which inputs a temperature-sensitive signal CRC and outputs measurement data KSD.
Reference numeral 7 denotes a CPU which inputs measurement data KSD and outputs temperature display data HD.

[0005] First, a conventional electronic temperature measurement operation will be described with reference to FIG. When the CPU 7 outputs the temperature measurement start signal EN at a predetermined sampling timing during temperature measurement, the measurement time counter unit 2 starts counting the reference signal X. On the other hand, the measurement counter 6 starts counting the temperature-sensitive signal CRC according to the environmental temperature KT. The coincidence circuit 4 starts comparing the fixed setting data SD1 with the count data CKD. Thereafter, when the fixed setting data SD1 and the count data CKD match, the matching circuit 4 outputs a match signal ZF. The measurement time counter section 2 and the measurement counter section 6 stop counting by the coincidence signal ZF, and the temperature measurement is completed. Since the reference signal X does not change with temperature, the temperature-sensitive signal CRC changes, the CPU converts the measurement data KSD for the time until the fixed setting data SD1 and the count data CKD coincide with each other, and converts the measurement data KSD to temperature data HD. I do.

Next, adjustment of a conventional temperature-sensitive oscillator will be described with reference to FIGS. Since the temperature-sensitive oscillator 5 has manufacturing variations and cannot be used as a thermometer as it is, the following adjustment is performed. First, in FIG.
FIG. 4-1 shows the frequency characteristics of the adjusted temperature-sensitive oscillator before temperature, and FIG. 4-2 shows the frequency characteristics of the adjusted temperature-sensitive oscillator against temperature. Case A shows that the manufactured thermistor oscillates with a large resistance. When the frequency is shifted in the slow direction, Case B is when the resistance value of the manufactured thermistor is ideal, and in Case C, the oscillation frequency is shifted in the fast direction because the resistance value of the manufactured thermistor is small. It is. Therefore, the cases A and C shown in FIG. 4-1 must be adjusted as shown in FIG. 4-2. In other words, the adjustment is performed by adjusting the frequency by using a variable capacitor such as a trimmer capacitor in the capacitor 54 shown in FIG. 3, and making the temperature indicated by the temperature display section 8 coincide with the environmental temperature KT. . The above is the description of the operation in the conventional example.

[0007]

As described above, in the conventional example, the adjustment of the characteristic variation of the temperature-sensitive oscillator takes a very long time to adjust, and the adjustment is finely adjusted. Had a very difficult problem.

It is an object of the present invention not only to perform temperature adjustment, but also to prevent an error in adjustment.

[0009]

Oscillation means for generating a reference signal, a measurement time counter for counting the reference signal, and count value setting means for setting a count value of the measurement time counter A matching circuit for determining whether a set value of the count value setting means matches a count value of the measurement time counter unit, a temperature-sensitive oscillator for generating a frequency corresponding to a temperature, and the temperature-sensitive oscillator In a thermometer having a measurement counter section for counting an oscillation signal from the CPU and a CPU for inputting the reference signal and performing temperature display, the count value setting means may include a temperature to which the temperature-sensitive oscillator is exposed. An environmental temperature data supply unit for supplying data, a measurement time memory for determining a measurement time of the temperature-sensitive oscillator, environmental temperature data of the environmental temperature data supply unit, and a measurement time And a data selection means for selecting and outputting the measured time data in the memory. Further, there is provided a signal switching unit for switching and supplying a reference signal of the oscillation unit and an oscillation signal of the temperature-sensitive oscillator to the measurement time counter unit and the measurement counter unit.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In the description of the present invention, the same elements and signals as those of the conventional example will be denoted by the same reference numerals and symbols, and description thereof will be omitted.

The configuration of the present invention will be described with reference to FIG. In FIG. 1, reference numeral 100 denotes a count value setting unit.
The configuration is as follows. Reference numeral 101 denotes a temperature data supply unit that outputs environmental temperature conversion data KTH. 102
Is a memory for measurement time, and generates measurement time data KJD. Reference numeral 103 denotes a data selection unit which inputs and selectively outputs the environmental temperature conversion data KTH and the measurement time data KJD. Reference numeral 200 denotes signal switching control means for selectively outputting the reference signal X and the temperature-sensitive signal CRC.

First, FIG. 4 shows the environmental temperature KT of the temperature-sensitive oscillator 5.
A case A is a case where the oscillation frequency of the temperature-sensitive oscillator 5 becomes the fastest due to the manufacturing variation of the thermistor 53, and a case B is a case where the thermistor 53 has the median value in the manufacturing. In this case, the oscillation frequency characteristic of the temperature-sensitive oscillator 5 is the slowest due to manufacturing variations of the thermistor 53. Incidentally, the environmental temperature conversion data KTH is calculated using the equation (1) for the case B shown in FIG. What is Case B? Environmental temperature conversion data KTH = Case B x Fixed measurement time n · · · (1)

Next, a method of adjusting the temperature-sensitive oscillator according to the present invention will be described with reference to FIGS. When adjusting the temperature-sensitive oscillator 5, the CPU 7 outputs a control signal CNT. Therefore, the signal switching control means 200 outputs the temperature sensing signal C
An RC terminal is output from a terminal Q1, and a reference signal X is output from a terminal Q2. That is, the input signal of the measurement time counter 2 is set to the temperature-sensitive signal CRC, and the input signal of the measurement counter 6 is set to the reference signal X. The data selection means 103 outputs the environmental temperature conversion data KTH from the Q terminal according to the control signal CNT. Next, the CPU 7 operates the operation permission signal EN.
Is output. The measurement time counter section 2 starts counting the temperature-sensitive signal CRC in advance, and the measurement counter section 6 starts counting the reference signal X. After that, when the count data CKD of the measurement time counter 2 matches the environmental temperature conversion data KTH, the matching circuit 4 outputs the match signal ZF, so that the measurement time counter 2 and the measurement counter 6 perform the counting operation. To stop. That is, the measurement data KSD output from the measurement counter unit 6 becomes the measurement time data KJD appropriate for the temperature-sensitive oscillator 5. Next, CPU7
Outputs the memory write signal VM and writes the measurement count data KSD to the measurement time memory 102. In other words, the temperature-sensitive oscillator 5, which has individual fluctuations when manufactured,
In other words, the temperature sensing frequency is adjusted as shown in FIG. 4-2 as in the case A and the case C shown in FIG. 4-1.
The above is the adjustment method.

Next, the operation in temperature measurement will be described.
Since the CPU 7 does not output the control signal CNT during the temperature measurement, the signal switching control means 200 outputs the reference signal X from the terminal Q1, and outputs the temperature-sensitive signal CRC from the terminal Q2. The data selection means 103 outputs the measurement time data KJD from the terminal Q. When the CPU 7 outputs the temperature measurement start signal EN, the measurement time counter unit 2 starts counting the reference signal X, and the measurement counter unit 6 starts counting the temperature sensing signal CRC. Thereafter, when the count data CKD of the measurement time counter unit 2 matches the measurement time data KJD, the coincidence circuit 4 outputs the coincidence signal ZF, so that the measurement time counter unit 2 and the measurement counter unit 6 perform the counting operation. Stop and temperature measurement is completed. Thereafter, the CPU 7 sets the measurement data KSD
Is used to output the temperature display data HD. The above is the operation in the temperature measurement.

[0015]

As is apparent from the above description, it is possible to provide a thermometer which can adjust not only a plurality of temperature-sensitive oscillators having variations simultaneously but also an environment temperature without making it constant.

[Brief description of the drawings]

FIG. 1 is a system configuration diagram of a thermometer according to the present invention.

FIG. 2 is a system configuration diagram of a conventional thermometer.

FIG. 3 is an example of a temperature-sensitive oscillator.

FIG. 4 is a frequency characteristic diagram with respect to a temperature of a temperature-sensitive oscillator.

[Explanation of symbols]

 REFERENCE SIGNS LIST 100 count value setting means 101 temperature data supply unit 102 measurement time memory 103 data selection means 200 signal switching means

Claims (1)

[Claims] An oscillating means for generating a reference signal; a measurement time counter for counting the reference signal; a count value setting means for setting a count value of the measurement time counter; A matching circuit for determining whether the set value of the value setting means matches the count value of the measurement time counter unit, a temperature-sensitive oscillator for generating a frequency corresponding to the temperature, and an oscillation signal from the temperature-sensitive oscillator In a thermometer having a measurement counter unit for counting the temperature and a CPU for inputting the reference signal and displaying a temperature, the count value setting unit supplies temperature data to which the temperature-sensitive oscillator is exposed. An ambient temperature data supply unit, a measurement time memory for determining the measurement time of the temperature-sensitive oscillator, an ambient temperature data of the ambient temperature data supply unit, and a measurement time memory. Data selection means for selecting and outputting inter-data, signal switching means for switching the reference signal of the oscillation means and the oscillation signal of the temperature-sensitive oscillator to the measurement time counter section and the measurement counter section. thermometer.