JPH0113247B2 - - Google Patents

Description

[Detailed description of the invention]

[Technical Field of the Invention] The present invention relates to an electronic integration meter that converts an analog quantity of an analog input signal into a digital value and processes it. [Prior Art] With the development of electronic circuit technology, especially electronic computers, there has been a growing trend in the field of analog integrating meters to convert data into digital values for ease of calculation, storage, and transmission. It's here. In this type of instrument, an analog/digital converter (hereinafter referred to as an A/D converter) 1 is used as a means for converting an analog quantity into a digital value, as shown in Fig. 1.
1 and an integration circuit 12. That is, this converts the analog amount of the analog input signal input to the input terminal 10 into the A/D converter 11.
is converted into a digital value, and the digital value is integrated by an integration circuit 12. However, since the A/D converter 11 quantizes the output of an analog input signal into digital values that increase discretely with equal resolution, absolute precision can be obtained for low-level inputs. That was difficult. For example, A/D converter 1
For a maximum analog input of 1, the absolute error is 1/2 times the number of resolution bits, but it is less than the resolution of the A/D converter 11, that is, less than the LSB (lowest significant digit) in Figure 3. The analog quantity had an error of 100% (dotted line b in Figure 3). Therefore, this A/D converter 11 is suitable for electronic integration meters with a wide dynamic range of input signals.
When using A/D converter 1 for minute input
The output value of 1 lacked reliability as data. As a countermeasure to this problem, a method has been devised in which the resolution is improved by increasing the number of bits of the A/D converter 11, thereby converting even low-level input analog amounts into digital amounts with high reliability. However, this not only complicates the circuit of the A/D converter 11, but also increases the number of bits and complicates the integrator in the subsequent stage, resulting in an increase in cost. This is particularly disadvantageous when attempting to mass produce monolithic ICs. [Summary of the Invention] This invention was made in order to eliminate the drawbacks of the above-mentioned conventional products.
It is an object of the present invention to provide a highly reliable electronic integration meter that can easily improve A/D conversion accuracy by simply adding a simple circuit to a D converter. [Embodiment of the Invention] FIG. 2 shows an example of an electronic totalizer according to the present invention. In the figure, 21 is an A/D converter to which an analog input signal is applied via the input terminal 10, and is designed to output a digital value that linearly increases in proportion to the input signal. This A/
The output terminal of the D converter 21 is connected to one input terminal of the adder 22 and to the zero detector 24. The output terminal of the zero detector 24 is connected to the other input terminal of the adder 22. The zero detector 24 detects that the digital value corresponds to the analog signal zero. The adder 22
adds “0” to the digital value when the output of the zero detector 24 is “0”, and adds “0” or “1” to the digital value when the output of the zero detector 24 is “1”
, and "1" is added to the digital value every four times, for example, when the output of the zero detector 24 is "1". 2
3 is an integrator that sequentially integrates the output of the adder 22. Next, the operation of the above configuration will be explained. Now, the maximum input voltage of the A/D converter 21 is 5V,
The resolution shall be 8 bits. Input analog amount
When the voltage is 19.5mV (5V/ ²⁸ ) or more, the A/D converter 21
Since at least one bit of the output is "1", and at this time the output of the zero detector 24 is "0",
The output of adder 22 matches the output digital value of A/D converter 21. Input analog amount is 19.5mV
Below, the output of the zero detector 24 becomes "1". Therefore, the output of the adder 22 is the value obtained by adding "0" or "1" to the output of the A/D converter 21,
In other words, it becomes 00000000 or 00000001. Here, the adder 22 determines that the output of the zero detector 24 is "1".
If you repeat the operation of adding "1" only once every four times, you will get something like the table below.

〔Effect of the invention〕

As described above, according to the present invention, with a simple configuration in which a zero detector and an adder are added to an A/D converter with the same resolution as the conventional one, it is possible to easily eliminate errors in a minute range without increasing the number of bits. becomes less,
Therefore, it is possible to provide an electronic totalizer that can improve the reliability of data.

[Brief explanation of drawings]

FIG. 1 is a block configuration diagram of a conventional electronic totalizing meter, FIG. 2 is a block configuration diagram showing an example of an electronic totalizing meter according to the present invention, and FIG. 3 is an analog/digital conversion characteristic diagram of the present invention. FIG. 4 is a diagram showing a specific configuration of the electronic totalizer of the present invention. 21...Analog/digital converter, 22...
. . . adder, 23 . . . integrator, 24 .

Claims (1)

[Claims] 1. An analog/digital converter that converts an analog input signal into a digital value, a zero detector that detects that the digital value is a value corresponding to zero of the analog input signal level, and An electronic integration meter comprising an adder that adds "1" to the output digital value of the analog/digital converter and outputs the result each time it detects , and an integrator that integrates the output of the adder.