JP3102108B2 - Oxygen concentration measurement device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for measuring oxygen concentration in air using an oxygen sensor.

[0002]

2. Description of the Related Art In recent years, environmental sensors such as temperature sensors, humidity sensors, pressure sensors, and oxygen sensors have been incorporated into electronic timepieces to display temperature, humidity, weather display, air contamination, and the like along with time. A number of electronic watches are planned and sold.

[0003] Among them, a sensor having a function of measuring the oxygen concentration in the air using an oxygen sensor is usually a galvanic oxygen sensor. This galvanic oxygen sensor detects the oxygen concentration and outputs it in the form of a voltage signal. The reaction formula at that time is shown as follows. That is,
When an acidic electrolyte is used, the positive electrode: O ₂ + 4H ⁺ + 4e ^- → 2H ₂ O negative electrode: 2Pb + 2H ₂ O → 2PbO + 4H ⁺ + 4e Total reaction: A reaction of a chemical formula of O ₂ + 2Pb → 2PbO.

[0004]

As shown in the above chemical formula, the reaction of the galvanic oxygen sensor is determined solely by the absolute amount of oxygen molecules in the air. The results will be different and the correct oxygen concentration cannot be known.

The present invention has been made in view of the above circumstances, and has as its object to measure an oxygen concentration capable of detecting a correct oxygen concentration in consideration of a change in atmospheric pressure and outputting a display. It is to provide a device.

[0006]

That is, the present invention provides an oxygen sensor for detecting the amount of oxygen molecules in air, a pressure sensor for detecting atmospheric pressure, and a standard amount of oxygen molecules for the atmospheric pressure in a table. A storage unit that stores the standard abundance of oxygen molecules with respect to the atmospheric pressure detected by the pressure sensor from the storage unit, and reads the standard abundance of oxygen molecules and the presence of oxygen molecules detected by the oxygen sensor. Since the volume percentage of oxygen is calculated from the amount and displayed and output, the amount of oxygen molecules detected based on the change in atmospheric pressure is corrected, and the correct oxygen concentration can always be displayed and output.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment in which the present invention is applied to a wristwatch having an oxygen concentration measuring function will be described below with reference to the drawings.

FIG. 1 shows the external structure of the case. Reference numeral 1 denotes a case body, and a display unit 2 formed by a liquid crystal display panel for displaying time, oxygen concentration, etc.
, An oxygen sensor 3 for detecting the amount of oxygen molecules present, and a pressure sensor 4 for detecting atmospheric pressure, while the case body 1 is provided.
Operation keys 5 and 6 for instructing switching of the display mode and measurement of the oxygen concentration are provided on the right side of the.

Next, the configuration of an electronic circuit provided in the case body 1 will be described with reference to FIG. In the figure, reference numeral 11 denotes a key switch unit composed of the operation keys 5 and 6, and a signal corresponding to a key operation on the key switch unit 11 is input to the CPU 12.

The CPU 12 controls the operation of other circuits as a whole. The CPU 12 receives time data from a clock circuit 13 and receives signals from a galvanic oxygen sensor 3 sent via an A / D converter 14. And the detection signal from the pressure sensor 4 sent via the A / D converter 15 are input.

The CPU 12 has a pressure-oxygen concentration table storage unit 16 storing a table of standard abundances of oxygen molecules corresponding to changes in atmospheric pressure, a ROM 17 storing operation programs and the like, and a ROM 17 for calculating a correct oxygen concentration. The data is input / output to / from each of the RAMs 18 holding the respective data, and the obtained oxygen concentration data and the time data from the clock circuit 13 are displayed and output on the display unit 2.

The pressure-oxygen concentration table storage unit 16 stores
As shown in FIG. 3, in consideration of the change in the absolute oxygen concentration caused by the change in the atmospheric pressure, for example, 1 atmosphere and 1013 mb
The standard abundance of oxygen molecules generated by a change in atmospheric pressure, such as 0.6%, is stored in advance as a table.
When the atmospheric pressure data is input from the CPU 12, the standard abundance of oxygen molecules corresponding to the atmospheric pressure data is extracted from the corresponding address and output to the CPU 12.

The RAM 18 has a P register 18a for storing the atmospheric pressure detected by the pressure sensor 4, and an X register 18 for storing the standard abundance of oxygen molecules corresponding to the change in atmospheric pressure.
b, an X 'register 18c for storing the measured abundance of oxygen molecules detected by the oxygen sensor 3 and a D register 18d for storing the calculated oxygen concentration.

A process for actually measuring the oxygen concentration in the above configuration will be described with reference to FIG. The figure is executed by the CPU 12 by operating a specific key, for example, the operation key 5 of the key switch section 11. At the beginning of the processing, A is executed in step S1.
The abundance of oxygen molecules detected by the oxygen sensor 3 via the / D converter 14 is sampled and captured as a digital value,
This is stored in the X 'register 18c of the RAM 18.

Next, in step S2, the CPU 12
The atmospheric pressure detected by the pressure sensor 4 is sampled via the A / D converter 15 and taken in as a digital value, which is also stored in the P register 18a of the RAM 18.

Thereafter, in step S3, the CPU 12 retrieves the standard abundance of oxygen molecules corresponding to the atmospheric pressure data stored in the P register 18a from the atmospheric pressure-oxygen concentration table storage unit 16 and stores it in the X register 18b of the RAM 18. Then, in step S4, the CPU 12 sets the X register of the RAM 18
20.6 × (X ′ / X) depending on the contents of 18b and X ′ register 18c

The calculation is performed, the calculation result is stored in the D register 18d of the RAM 18 as correct oxygen concentration data, and the oxygen concentration data is sent to the display unit 2 together with the time data from the clock circuit 13 as shown in FIG. The display of the time and the oxygen concentration as shown in FIG.

[0018]

As described above, according to the present invention, an oxygen sensor for detecting the amount of oxygen molecules in the air, a pressure sensor for detecting the atmospheric pressure, and a standard amount of oxygen molecules for the atmospheric pressure are stored in the table. A storage unit that stores the standard abundance of oxygen molecules with respect to the atmospheric pressure detected by the pressure sensor from the storage unit, and reads the standard abundance of oxygen molecules and the presence of oxygen molecules detected by the oxygen sensor. Since the volume percentage of oxygen is calculated from the amount and displayed and output, an oxygen concentration measurement device that can always display and output the correct oxygen concentration by correcting the abundance of oxygen molecules detected by the change in atmospheric pressure is provided. Can be provided.

[Brief description of the drawings]

FIG. 1 is a diagram showing an external configuration according to an embodiment of the present invention.

FIG. 2 is a block diagram showing a configuration of an electronic circuit provided in a case body of FIG. 1;

FIG. 3 is a view showing the concept of a table stored in an atmospheric pressure-oxygen concentration table storage unit in FIG. 2;

FIG. 4 is a flowchart showing processing content of oxygen concentration measurement by the CPU of FIG. 2;

[Explanation of symbols]

1… Case body, 2… Display unit, 3… Oxygen sensor, 4… Pressure sensor, 5, 6… Operation key, 11… Key switch unit, 12
... CPU, 13 ... clock circuit, 14, 15 ... A / D converter, 16 ...
Atmospheric pressure-oxygen concentration table storage unit, 17 ROM, 18 RA
M, 18a ... P register, 18b ... X register, 18c ... X '
Register, 18d ... D register.

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) G01N 27/404 G01N 27/26 371

Claims (1)

(57) [Claims] A first detecting means for detecting the amount of oxygen molecules present in the air; a second detecting means for detecting atmospheric pressure; a storing means for storing a standard amount of oxygen molecules with respect to the atmospheric pressure; Reading means for reading out the standard abundance of oxygen molecules with respect to the atmospheric pressure measured by the second detecting means from the storage means; standard reading of oxygen molecules read by the reading means and oxygen detected by the first detecting means An oxygen concentration measuring device comprising: a calculating means for calculating a volume percentage of oxygen from an abundance of a molecule; and a display means for displaying and outputting the volume percentage of oxygen obtained by the calculating means.