JP2002005684A - Arithmetic processor for a/d converter output value, and display processor for numerical value display using the processor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a resolution of not lower than a resolution proper to an A/D converter by arithmetically processing output values of the A/D converter by the use of microcomputer. SOLUTION: A CPU 5 arithmetically processes and outputs, by adding output values of a plurality of the number of times outputted at prescribed time intervals from the A/D converter 3 and dividing the added value by a value smaller than the number of times, whereby a resolution obtained the arithmetic output value is improved more than the resolution which is proper to the A/D converter 3. In particular, the processor is useful as the display processor for adapting and displaying to the numerical value display, having a resolution larger than the resolution proper to the A/D converter 3.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an arithmetic processing device for an A / D converter output value and a display processing device for a numerical display using the same.

[0002]

2. Description of the Related Art When an analog value is converted into a digital value by an A / D converter and then displayed on a numerical display, the numerical range desired to be displayed on the numerical display exceeds the resolution of the A / D converter. If it is, it cannot cover the numerical range to be displayed on the numerical display. For example, if the numerical value range to be displayed on the numerical value display is 0 to 1406, and the A / D converter has a resolution of 10 bits, the output value range of the A / D converter is 0 to 1023.
Therefore, the numerical value range to be displayed on the numerical value display cannot be covered. Therefore, generally, an A / D converter having a high resolution, for example, a 12-bit resolution is required. In the case of a 12-bit A / D converter, the resolution is 4096, that is, since there is an output value range of 0 to 4095, it is possible to cover the numerical range to be displayed on the numerical display. As another method, the use of two 10-bit A / D converters in parallel is introduced. In this case, since the resolution can be set to 2047, it is possible to cover a numerical range to be displayed on the numerical display.

[0003]

However, in the above method, the resolution is fixed. In recent years, electronic devices are almost always equipped with microcomputers, which achieve various functions. And A / D as described above
If it is assumed that a converter is used, a microcomputer incorporating an A / D converter is often used to reduce the size and cost of the device. However, A / D converters built in microcomputers have many kinds of low-bit A / D converters and are inexpensive, whereas microcomputers with built-in high-bit A / D converters have few kinds and are expensive. Therefore, in the present invention, in consideration of such a situation, the output value of the A / D converter is arithmetically processed by using a microcomputer, and thereby the A / D conversion is performed.
The purpose is to obtain a resolution higher than the resolution inherent in the converter, especially when the numerical range to be displayed on the numerical display exceeds the resolution of the A / D converter.
The purpose is to cover the range of numerical values to be displayed on the numerical display.

[0004]

Means for solving the problems are as described in the claims.

[0005]

BEST MODE FOR CARRYING OUT THE INVENTION Next, an embodiment of the present invention will be described. However, this is merely an exemplary embodiment adopted based on the present invention, and the present invention will be described based on matters unique to the embodiment. Therefore, the technical scope of the present invention should be determined based on the matters stated in the claims and matters substantially equivalent to the matters.

FIG. 1 shows a circuit block diagram. An analog quantity output from a sensor 1 such as a fluid pressure sensor is represented by an amplifier 2.
And then input to the A / D converter 3.
The microcomputer 4 shown here incorporates the A / D converter 3 and the decoder 6 in addition to the CPU 5 which is the heart. The analog value is converted into a digital value by the A / D converter 3 and output.
The arithmetic processing is performed by the PU5. Further, the output of the arithmetic processing by the CPU 5 is converted through a decoder 6 and numerically displayed as a pressure value or the like on a 7-segment type numerical display 7.

Here, the CPU 5 adds a plurality of output values output from the A / D converter 3 at predetermined time intervals, divides the added value by a value smaller than the above-mentioned number, and outputs the result. This is characterized in that the resolution based on the calculated output value is improved more than the resolution inherent in the A / D converter 3.

This device is particularly useful as a display processing device for adaptively displaying a numerical value display 7 having a resolution larger than the resolution inherent in the A / D converter 3.
The PU 5 adds a plurality of output values output from the A / D converter 3 at a predetermined time interval, divides the added value by a value smaller than the number of times, and outputs the result by a calculation process. The resolution based on the value is improved over the resolution inherent in the A / D converter 3 and the numerical display 7
Is obtained by obtaining a resolution higher than the numerical value range to be displayed on the numerical display 7.

More specifically, referring to the functional block diagram shown in FIG.
Using a bit-type one, 11 output values output from the A / D converter 3 at predetermined time intervals are added, and this added value is a value smaller than the number of times 8
, And outputs the result of the arithmetic processing, the resolution based on the arithmetic output value is set to 1407, which is higher than the resolution 1024 inherent to the A / D converter 3.

[0010] More specifically, the analog voltage output from the amplifier 2 is in the range of 0 to 5 V, and usually fluctuates with the passage of time. This voltage is input to the A / D converter 3, converted at predetermined time intervals, output at predetermined time intervals, and has 1024 levels of resolution from 0 to 1023 as its output value. The output of the A / D converter 3 is sequentially input to the CPU 5, and the CPU 5 adds 11 input values input at predetermined time intervals, divides by 8, and outputs an arithmetic processing. 140 from 0 to 1406 as the value
Seven levels of resolution are obtained.

[0011] The input values of 11 times input to the CPU 5 are all the maximum output values of the A / D converter 3 1023.
In the case of, the sum is 11253. Then, if 11253 is divided by 8, it becomes 1406 (the fractional part is rounded down), and this numerical value becomes the maximum value of the calculation output of the CPU 5. The CPU 5 is programmed to perform such arithmetic processing in accordance with the eleven input values input to the CPU 5, and as the arithmetic output value of the CPU 5, the numerical range of 1407 levels from 0 to 1406 is used as described above. It has gained.

The following Table 1 shows that the CPU 5 executes the A
3 shows a part of the arithmetic processing for adding the output value of the / D converter 3 and dividing by 8 to output the arithmetic result. Note that the “calculated output value” shown in Table 1 is a value obtained by dividing the sum of 11 times by 8 and rounding down the value after the decimal point.

[Table 1] As shown in Table 1, the output values of the A / D converter 3 for the eleventh time are subjected to arithmetic processing, thereby obtaining “operation output values” from 0 to 11 and the maximum value of the above-mentioned operation output of 14.
A numerical range up to 06 can be obtained without skipping numerical values. And
The operation output value output from the CPU 5 is converted by the decoder 6 into a signal adapted to the numerical display 7 and displayed on the numerical display 7 as a display pressure value. As shown in Table 1, the output value of the A / D converter 3 normally fluctuates with the passage of time.
The above-described arithmetic processing based on the output value of the converter 3 is also useful in capturing the fluid pressure and the like detected by the sensor 1 as an average value.

The numerical display 7 is of a "3 and 1/2 digit" type which can also display, for example, a minus (-) sign.
A range from 1999 to 0 to 1999 can be displayed. However, in most cases, it is not necessary to use the entire range, and as the numerical range to be displayed, for example, 100 steps of display margin and 100 steps of atmospheric pressure correction according to the place of use are added to the basic 1000 steps. Then, for example, there are 1200 steps. The unit is kPa (kilopascal), and none of the three decimal points on the numerical value display 7 are lit.

Then, the numerical value range to be displayed on the numerical value display 7 becomes larger than the 1024 steps which are the output values of the A / D converter 3, and the numerical value range to be displayed on the numerical value display 7 cannot be covered. The present invention is particularly useful as a display processing device in such a case. When the CPU 5 outputs the calculation processing as described above, the resolution based on the calculation output value is 1024 steps, which is the resolution unique to the A / D converter 3. To 1407 stages,
The resolution higher than the numerical range to be displayed on the numerical display 7 is obtained, and the range to be displayed on the numerical display 7 can be satisfied. As described above, the calculation output value of the CPU 5 is 0.
Corresponding to the fact that the numerical range from 1406 to 1406 can be obtained without skipping numerical values, the numerical value of the lowest digit (one digit) of the numerical display 7 can be obtained without skipping numerical values, and the user does not feel uncomfortable.

FIG. 3 is a functional block diagram according to another embodiment for displaying 100.0 kPa to -100.0 kPa up to the lowest digit without skipping. In this case, only the decimal point indicated by the symbol a among the three decimal points of the numerical value display 7 shown in FIG. In this case, a resolution of 2001 levels is required for display, and a minimum of 200 levels is required in consideration of display margin and atmospheric pressure correction, which is a resolution inherent to the A / D converter 3.
At the stage of 024, it is completely insufficient.

Therefore, the CPU 5 adds the eleven output values output from the A / D converter 3 at predetermined time intervals, and divides the added value by 4, which is a value smaller than the above number. By changing the program to output the arithmetic processing, the resolution based on the arithmetic output value may be set to 2814, and may be improved from 1024, which is the specific resolution of the A / D converter 3. In this way, just changing the program according to the numerical range you want to display
Since the resolution can be improved by the arithmetic processing of U5, the degree of freedom is large.

In the embodiment described above, the CP
As the function of U5, only the function for displaying the detected pressure on the numerical display 7 has been described. However, the function for generating and outputting a control signal in accordance with the detected pressure to control an actuator (not shown) or the like is also described. The A / D converter 3 may be carried by the CPU 5, and in such a case, the A / D converter
Performing arithmetic processing using the CPU 5 to obtain a resolution higher than the intrinsic resolution has the advantage that no separate component is required. Also, just in case, the improvement of the resolution described above is not an improvement in the resolution in a strict sense, but an improvement in the resolution in the sense that the number of steps is increased by the CPU 5 in order to display the data on the numerical display 7 appropriately. In most applications other than those requiring extremely strict display and control functions, industrially useful use can be achieved.

As described above, according to this embodiment, the output value of the A / D converter 3 is subjected to arithmetic processing using the microcomputer 4 (CPU 5), whereby a resolution higher than the resolution inherent in the A / D converter 3 can be obtained. In particular, when the numerical range to be displayed on the numerical display 7 exceeds the resolution of the A / D converter 3, the numerical range to be displayed on the numerical display 7 can be covered with a high degree of freedom.

[Brief description of the drawings]

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

FIG. 2 is a functional block diagram showing an embodiment of the present invention.

FIG. 3 is a functional block diagram showing another embodiment of the present invention.

[Explanation of symbols]

 3 A / D converter 4 Microcomputer 5 CPU 7 Numerical display

Claims (2)

[Claims] An analog amount taken into an A / D converter is converted into a digital value and output, and the output value is output to a CPU.
A CPU that adds a plurality of output values output from the A / D converter, divides the added value by a value smaller than the number of times, and outputs the result by arithmetic processing. A that improves the resolution based on the calculated output value over the resolution inherent in the A / D converter
Arithmetic processing unit for / D converter output value. 2. An analog amount taken into an A / D converter is converted into a digital value and output.
And a display processing device for displaying the calculated output value via a decoder on a numerical display having a resolution greater than the resolution inherent in the A / D converter. The output value output from the A / D converter is added, and the addition value is divided by a value smaller than the number of times, and the result is subjected to arithmetic processing output. A display processing device for a numerical display, wherein a resolution higher than a numerical range desired to be displayed on the numerical display is obtained by improving the numerical display and the numerical display is displayed.