JPS644603B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an improvement in a digital display type gas analyzer.

[Conventional technology]

BACKGROUND OF THE INVENTION Gas analyzers that display analysis result information using an optical seven-segment numeric display have become popular. One example is an oxygen concentration meter, which displays the oxygen concentration in the measured gas as a percentage.This device can display up to one decimal place, such as 21.5%. There are many things you can do. However, when this device is actually used, the display of one decimal place changes over time, making the measured value unstable. Furthermore, in practice, it is often unnecessary to display the decimal places. For this reason, it is conceivable to round off the measured analysis information to one decimal place and display it as a decimal point or higher.

However, to calibrate this device, the sensitivity is adjusted by measuring a standard gas (in the case of oxygen meters, atmospheric air is generally a very good standard), which is an order of magnitude more accurate than normal measurements. It would be more convenient to display the decimal places. For this reason,
Some conventional devices have been improved by providing a switch to display the decimal point only during calibration.

[Problem that the invention seeks to solve]

However, using this improved device is quite cumbersome. In particular, the people who use this kind of equipment are often not experts, so they may display the decimal point at times other than calibration to express their dissatisfaction with the decimal point, which has no inherent calculation accuracy, so it is inappropriate for the product. Not.

The present invention improves this, and it is possible to avoid misconceptions such as measurements being made to an accuracy of one digit lower during general measurements.Furthermore, when performing calibration with standard gases, it is possible to avoid errors such as the accuracy of measurements being one digit lower than during general measurements. It is an object of the present invention to provide a device that can display and calibrate up to digits.

[Means for solving problems]

In the present invention, when measuring a standard gas and calibrating the device, it is sufficient that the concentration of the standard gas remains unchanged and that the same value is always displayed for the first lower digit, which is unnecessary for normal measurements. This is what we focused on.

In other words, the present invention uses a special symbol only when one number in the lower digit corresponding to the value of the standard gas or a small number of numbers in the permissible range following this number are output as analysis result information. It is characterized by comprising means for performing optical display.

〔Example〕

This will be explained in detail using embodiment drawings.

FIG. 1 is a block diagram of an apparatus according to an embodiment of the present invention. This is an example of an oxygen concentration meter, and the sensor S
The output signal of is input to the converter AD via the amplifier AMP. This converter AD outputs a four-digit digital signal according to the input signal, and the top three digits are displayed on the numeric display DP. Also converter
The least significant digit of AD is led to a digit detector DET, the output of which is arranged to display the decimal point of the digit display DP.

Here, sensor S, amplifier AMP and converter
AD is a means of analyzing the concentration of specific gas components contained in the gas to be measured. The numeric display DP is an optical display means. These are well known, and detailed explanation thereof will be omitted.

The amplifier AMP has a gain adjuster ADJ. When calibrating this device, the sensor S is exposed to a standard gas and the gain adjuster ADJ is adjusted so that the display corresponds to the concentration of the standard gas. Also, the reference voltage is applied to the input of the converter AD.
E _s is given, but this is for rounding off, for example to add an amount equivalent to 0.5% to the input voltage. For example, if the input is in the range of 20.5% to 21.4%, the output will be 21%.

The features of the present invention in this configuration are as follows:
The least significant digit of the converter AD, here the first decimal point
The digit information is led to a number detector DET, and when a specific number is input here, the decimal point of the number display DP is configured to light up.

To explain this in more detail, the standard gas for calibrating an oxygen concentration meter is generally the atmosphere, and its oxygen concentration is 21.0%. This remains constant in most areas of the globe. As mentioned above, 0.5% is added for rounding based on the reference voltage E _s , so
It is correct to calibrate so that 21.5% appears at the output of the converter AD. Therefore, in this embodiment device, the numbers "4" and "5" are placed in the lowest digit of the converter AD.
It is detected that any one of "6" is sent.

FIG. 2 is a basic configuration diagram of this number detector DET. This is a 7 segment signal a, b, f
This circuit detects that a and b are different and f is "1". That is, for the seven segments of numerical display, the symbols a to
If g is added, from the table shown in Figure 4, in order to detect whether the number is "4", "5", or "6", a and b are different and f is "1". If we detect something, we know that it is necessary and sufficient. FIG. 2 is composed of one exclusive OR circuit and two AND circuits.

In this way, the least significant digit of the output of converter AD is
The value ``4'', ``5'', or ``6'' means that 21.4, 21.5, or 21.6 is being output from the converter AD during calibration using the standard gas. At this time, the decimal point on the numeric display DP lights up, so if you operate the adjuster ADJ and adjust it to the middle position of the lighting range, you can perform correct calibration.

Of course, it may be configured so that the decimal point lights up only when the lowest digit is the correct number "5", but when actually used, the correct number "5" is displayed.
It is more convenient to display a permissible range of about 3 numbers around , as it provides a wider range of adjustment, and in practice, this degree of error is not a problem at all.

In the above example, the gas analyzer is an oxygen concentration meter,
Although it is assumed that the standard gas for calibration is the atmosphere, the present invention can be practiced using any kind of gas analyzer and any kind of standard gas. As mentioned above, the number detected by the number detector may be just one digit,
It may be 3 to 5 consecutive digits.

In the above example, the special symbol is used as a decimal point, but any other symbol may be used.

〔Effect of the invention〕

As explained above, according to the present invention, the display of one lower digit is not substantially recognized under normal use conditions, thereby eliminating misidentification, and when performing calibration, the accuracy is substantially one order higher than the normal display. A device for displaying is obtained. Compared to a device that is equipped with a switch so that the final digit is not displayed except during calibration, an excellent gas analyzer is obtained that is less troublesome to handle and does not raise any questions from the user.

[Brief explanation of drawings]

FIG. 1 is a configuration diagram of an apparatus according to an embodiment of the present invention. FIG. 2 is a diagram showing an example of the configuration of a number detector. FIG. 3 is a diagram showing a 7-segment numeric display. Figure 4 is a logic table for a 7-segment numeric display.

Claims (1)

[Scope of Claims] 1. A gas analyzer comprising means for analyzing the concentration of a specific gas component contained in a gas to be measured, and means for optically displaying the analysis results of this means in numerical form, comprising: The means includes means for analyzing at least one digit lower than the least significant digit displayed by the number on the displaying means, and outputting information of the analysis result by this means to the displaying means as information of a rounded number. and the displaying means outputs a correct number corresponding to the analysis result of a specific calibration standard gas or a range allowable from the correct number as information of the one lower digit from the outputting means. A gas analyzer characterized in that it includes means for optically displaying a special symbol when the digits are being delivered. 2. The specific gas is oxygen, the specific calibration standard gas is the atmosphere, and the correct number corresponding to the analysis result of the specific calibration standard gas is the standard oxygen concentration of the atmosphere "21.0%".
The gas analyzer according to claim 1, wherein the value is "5", which is the sum of the number "0" in the first decimal place and an additional value "5" for rounding. 3. The specific gas is oxygen, the specific calibration standard gas is the atmosphere, and the correct number corresponding to the analysis result of the specific calibration standard gas is the standard oxygen concentration of the atmosphere "21.0%".
The value "5" is obtained by adding the additional value "5" for rounding to the number "0" in the first decimal place, and the numbers within the allowable range from the correct number are "4" and "5".
and "6", the gas analyzer according to claim 1.