JPH05281183A - Oxygen concentration detection device - Google Patents

Abstract

PURPOSE:To achieve actual and effective ventilation by compensating a standard oxygen concentration according to the pressure within a chamber, calculating an oxygen concentration closer to the outdoor oxygen concentration, and then using the difference between the oxygen concentration and the measured one within the chamber as a reference data. CONSTITUTION:It is judged whether a minute carry is generated or not and a signal is sent to an amplification circuit 7 and an A/D conversion circuit 8 when the minute carry is generated for obtaining an oxygen concentration data and then the measured oxygen concentration is set to a RAM 12. Then, a signal is sent to a pressure sensor 9, an amplification circuit 10, and an A/D conversion circuit 11 for obtaining pressure data and then the measured pressure is set to the RAM 12. Then, it is judged whether the oxygen concentration data according to the current measurement exceeds a reference oxygen concentration data or not. When it does, the current oxygen concentration data is set to the RAM 12 as the reference oxygen concentration data. A week carry is examined by a data counter circuit 4, automatic reset is performed when there is the week carry, and then the maximum oxygen concentration data is set to the RAM 12 as the reference oxygen concentration data.

Description

Detailed Description of the Invention

[0001]

[Industrial field of use] An oxygen concentration detector that detects the oxygen concentration in an environment where the oxygen concentration decreases over time, such as in a room using an oil stove, and indicates the degree of ventilation with the outdoors. Regarding

[0002]

2. Description of the Related Art Conventionally, an oxygen concentration detecting device equipped with an oxygen sensor or the like for detecting the oxygen concentration in a placed environment is
Detects the oxygen concentration in an environment where the oxygen concentration decreases over time, such as in a room using an oil stove,
There is a type that displays the degree of decrease in oxygen concentration and the degree of ventilation required, that is, the ventilation level.

[0003]

By the way, the above-mentioned oxygen concentration detecting apparatus uses the outdoor oxygen concentration as a constant standard oxygen concentration when calculating the oxygen concentration decrease degree and the ventilation level, and detects the oxygen concentration in the room. The difference from the concentration is used as the basic data. However, in reality, the outdoor oxygen concentration is not constant but changes in proportion to a change in atmospheric pressure, and when the atmospheric pressure decreases, the oxygen concentration also decreases. Therefore, the oxygen concentration detection device as described above, for example, the inside of the room has a low oxygen concentration to some extent due to the use of a petroleum stove, etc. There was a problem of displaying a constant ventilation level indicating the need for ventilation, even when was completely wasted. The present invention has been made in view of the above circumstances, and an object of the present invention is to provide an oxygen concentration detection device capable of recognizing the required degree of ventilation taking into consideration the actual effectiveness of ventilation.

[0004]

In order to achieve the above object, the present invention measures the atmospheric pressure at the time of measuring the indoor oxygen concentration and corrects the standard oxygen concentration by this atmospheric pressure to correct the time. The oxygen concentration close to the actual outdoor oxygen concentration was calculated, and the ventilation level was obtained using the difference between this oxygen concentration and the measured indoor oxygen concentration as basic data.

[0005]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a circuit configuration diagram of an oxygen concentration detection device according to the present embodiment. In the figure, the reference clock signal generated by the oscillation circuit 1 is divided into a predetermined frequency by the frequency dividing circuit 2 and output to the time counting circuit 3. Time counting circuit 3
Counts the clock signal from the frequency dividing circuit 2 to obtain time data, and outputs the time data to the CPU 5 together with the minute carry. The date counting circuit 4 counts the day carry signal from the time counting circuit 3 to obtain date data, and outputs the date data to the CPU 5 together with the week carry signal.

The oxygen sensor 6 is composed of, for example, a galvanic cell type oxygen sensor and outputs a voltage proportional to the oxygen concentration in the air. The output voltage of the oxygen sensor 6 is amplified by the amplifier circuit 7, converted by the A / D conversion circuit 8 into an 8-bit digital value of 0 to 255, and output to the CPU 5. The amplifier circuit 7 and the A / D conversion circuit 8 are driven by the measurement signal output from the CPU 5 at 1-minute intervals. Pressure sensor 9
Is a circuit unit that outputs a voltage proportional to atmospheric pressure. The amplifier circuit 10 amplifies the output of the pressure sensor 9 and A / D conversion circuit 11
Give to. The A / D conversion circuit 11 is a circuit unit that converts the output from the amplification circuit 10 into a digital value and gives it to the CPU 5.

The CPU 5 is a central processing unit for controlling the entire circuit, stores the oxygen concentration data detected by the oxygen sensor 6 in the RAM 12, and drives the display drive circuit 13 to display time and date data. It is displayed on the section 14.

The display unit 14 is composed of a liquid crystal display or the like,
Ten level indicators 14a to indicate the ventilation level on the upper part
14j are provided, and all of them are turned on up to the ventilation level 1 where ventilation is not generally required, and thereafter, as the ventilation level becomes higher, more of them are turned off. A segment display is provided at the center and lower part of the display unit 14 to display the date and time.

The key processing unit 15 is provided with a plurality of keys which are operated at the time of time correction, start of measurement of oxygen concentration, etc., and operation signals of these keys are output to the CPU 5. FIG. 2 is a diagram showing the configuration of the register of the RAM 12, R
The AM 12 has a measured oxygen concentration storage unit X that stores oxygen concentration data detected by the oxygen sensor 6, and a maximum value of a plurality of oxygen concentration data measured at regular intervals (eg, every week) as the reference oxygen. A reference oxygen concentration storage unit Y that stores concentration data and a level storage unit Z that stores a ventilation level
A measured pressure storage unit P that stores atmospheric pressure data that is measured each time the oxygen concentration data stored in the measured oxygen concentration storage unit X is measured, and reference oxygen concentration data that is stored in the reference oxygen concentration storage unit Y. Pressure storage unit Q for storing reference concentration, which stores pressure data for storing reference concentration measured at each measurement
And a counter I for counting the number of measurements when obtaining the reference oxygen concentration data.

Next, the operation of this embodiment configured as described above will be described. FIG. 3 is a general flowchart showing the outline of the operation. That is, step S1
Then, it is determined whether there is a minute carry. If there is a minute carry, the process proceeds to step S2 and the amplifier circuit 7 and the A / D
A signal is sent to the conversion circuit 8 to drive it to obtain oxygen concentration data, which is set in the measured oxygen concentration storage unit X. Then, in step S3, the pressure sensor 9, the amplification circuit 10 and the A / D conversion circuit 11 are set. A signal is sent to drive and obtain atmospheric pressure data, which is set in the measured pressure storage unit P. Then, in the subsequent step S4, it is determined whether the oxygen concentration data set in the measured oxygen concentration storage unit X by the present measurement exceeds the reference oxygen concentration data in the reference oxygen concentration storage unit Y, and the oxygen concentration data exceeds the reference oxygen concentration data. Is displayed,
In step S5, the oxygen concentration data of this time is set as the reference oxygen concentration data in the reference oxygen concentration storage unit Y,
Further, the atmospheric pressure data by the current measurement set in the measured pressure storage unit P in step S6 is set in the reference concentration storage pressure storage unit Q as the atmospheric pressure at the time of measuring the reference oxygen concentration data. When the process of step S6 is completed or when a negative determination is made in step S4, the process proceeds to step S7, and the reference oxygen concentration data in the reference oxygen concentration storage unit Y is set to the atmospheric pressure in the reference concentration storing pressure storage unit Q. Divided by to obtain the reference oxygen concentration data under the current atmospheric pressure by multiplying it by the atmospheric pressure of the measured pressure storage unit P, and from this the oxygen concentration data of the measured oxygen concentration storage unit X is subtracted to obtain the ventilation level. Is set in the level storage section Z. Then step S8
Then, it is checked from the date counting circuit 4 whether there is a week carry, and if there is a week carry, step S9, that is, the automatic reset process of FIG. 4 is executed. That is, in step S20 of FIG. 4, the reference oxygen concentration storage unit Y is cleared, in step S21, the counter I is set to 1, and in the next step S22, a signal is sent to the amplifier circuit 7 and the A / D conversion circuit 8 to send oxygen. The concentration is measured and the obtained oxygen concentration data is set in the measured oxygen concentration storage unit X. Next, in step S23, a signal is sent to the pressure sensor 9 or the like to measure the atmospheric pressure, and the obtained atmospheric pressure data is set in the measured pressure storage unit P. In step S24, the oxygen concentration data in the measured oxygen concentration storage unit X is used as a reference. It is determined whether or not the reference oxygen concentration data in the oxygen concentration storage unit Y is exceeded, and if it exceeds, the process proceeds to step S25 (in this case, in step S20, the reference oxygen concentration storage unit Y is used.
Has been cleared, the determination in step S24 is always positive). In step S25, the oxygen concentration data in the measured oxygen concentration storage unit X is set in the reference oxygen concentration storage unit Y as reference oxygen concentration data, and in step S26, the atmospheric pressure in the measured pressure storage unit P is set as the reference atmospheric pressure and the reference concentration storage pressure is stored. Set in Part Q. Next, in step S27, it is determined that the value of the counter I is not 5, and the process proceeds to step S28 to execute an increment process to increment the value of the counter I by 1
Return to 22. Hereinafter, operations similar to those described above (step S2)
2 to S28), step S2 each time
In step 8, the value of the counter I is incremented by 1, and when the value of the counter I reaches 5, it is changed to step S2.
7, and the automatic reset process ends. That is, the automatic reset process is performed every beginning of the week, and in this process, the measurement of the oxygen concentration and the like is continuously performed five times, and the maximum of the oxygen concentration data of each time is used as the reference oxygen concentration data. It is set in the density storage unit Y. It should be noted that the automatic reset process is performed as a countermeasure against a decrease in output of the oxygen sensor 6 due to secular change.

After the automatic reset process is completed as described above, the process proceeds to the display process of step S10 in FIG. 3 to display various data on the display unit 14. That is, first, the ventilation level of the level storage unit Z is displayed by using the level indicators 14a to 14j. In this case, as shown in FIG. When the ventilation level of the section Z is a value up to 1, all of the level indicators 14a to 14j are turned on, and thereafter, as the ventilation level becomes higher, the number of lights to be turned off is decreased and the number of lights to be turned off is increased. When it reaches from 29 to 33, all are turned off, and when the ventilation level becomes 34 or more, all of the level indicators 14a to 14j blink. In the display processing, after the ventilation level is displayed, the date data and the current time data from the date counting circuit 4 and the time counting circuit 3 are respectively utilized by using the element display bodies at the central portion and the lower portion of the display unit 14. indicate.
However, for example, when the ventilation level is a value up to 1 at 8:35:20 on January 23 (Monday), the display unit 1
The display of 4 is as shown in FIG. 6 (a), and
Time has passed from the time of this display state, 11: 4 on the same day
When the ventilation level reaches a value between 8 and 9 at 0 minutes and 15 seconds, the display on the display unit 14 becomes as shown in FIG.

After the display process of step S10 in FIG. 3 is completed, the process returns to step S1. Also, step S1
If it is determined that there is no minute carry in step S, step S
11, it is determined whether or not there is a key input, and if there is a key input, the corresponding key processing is executed in step S12 and then the display processing of step S10 is performed, but if there is no key input, directly, The process proceeds to the display process of step S10. After finishing the display process, the process returns to step S1.

[0013]

As described above in detail, the present invention measures the atmospheric pressure at the time of measuring the indoor oxygen concentration,
The oxygen concentration is detected by correcting the standard oxygen concentration with this atmospheric pressure to calculate an oxygen concentration close to the actual outdoor oxygen concentration, and obtaining the ventilation level using the difference between this oxygen concentration and the measured indoor oxygen concentration as basic data. Since it relates to the device, it is possible to provide an oxygen concentration detection device capable of recognizing the required degree of ventilation taking into consideration the actual effectiveness of ventilation.

[Brief description of drawings]

FIG. 1 is a diagram showing a circuit configuration of an embodiment of the present invention.

FIG. 2 is a diagram showing a configuration of a RAM shown in FIG.

FIG. 3 is a general flowchart showing an outline of the operation of the above embodiment.

FIG. 4 is a flowchart showing in detail the automatic reset process in FIG.

FIG. 5 is a diagram showing a relationship between a ventilation level and a display mode of a level indicator.

FIG. 6 is a diagram showing a display example of a display unit.

[Explanation of symbols]

 6 Oxygen sensor 7, 10 Amplification circuit 8, 11 A / D conversion circuit 9 Pressure sensor 12 RAM 13 Display drive circuit 14 Display section 14a to 14j Level indicator X Measured oxygen concentration storage section Y Reference oxygen concentration storage section Z Level storage section P Measurement pressure storage unit Q Reference concentration storage pressure storage unit I Counter

Claims (2)

[Claims] 1. An oxygen sensor, an oxygen concentration generating means for obtaining measured oxygen concentration data from the output of the oxygen sensor, a pressure sensor, an atmospheric pressure data generating means for obtaining atmospheric pressure data from the output of the pressure sensor, and the oxygen concentration. Reference data setting means for setting and storing the measured oxygen concentration data obtained by the generating means and the atmospheric pressure data obtained by the atmospheric pressure data generating means when the measured oxygen concentration data is obtained, respectively as reference oxygen concentration data and reference atmospheric pressure data. And the measured oxygen concentration data obtained by the oxygen concentration generation means after the reference oxygen concentration data and the reference pressure data are set by the reference data setting means, and the atmospheric pressure data generation when the measured oxygen concentration data is obtained. Acid for obtaining an oxygen concentration level from atmospheric pressure data obtained by means, said reference oxygen concentration data and said reference atmospheric pressure data Oxygen concentration detection apparatus; and a density level calculating means. 2. The corrected oxygen concentration level calculating means obtains corrected oxygen concentration data by correcting the oxygen concentration data according to a ratio between the atmospheric pressure data and the atmospheric pressure data during measurement. 2. The oxygen concentration detection device according to claim 1, further comprising: a means for obtaining the oxygen concentration level from the corrected reference oxygen concentration data obtained by the corrected reference oxygen concentration data calculation means and the measured oxygen concentration data.