JPH04227118A - Method and device for eliminating data noise - Google Patents

Abstract

PURPOSE:To obtain a method and a device capable of surely eliminating noise on analog data. CONSTITUTION:This device is comprised of sampling step 101 in which the analog data DA is sampled at a period T, sampling number of times count step 102 in which the number (n) of times of sampling in the sampling step 101 is counted and the prescribed number N of times and a data output command SC are outputted when it arrives at the prescribed number N of times, data addition step 103 in which sampling data sampled in the sampling step 101 is added sequentially and from which a data addition result value SIGMA until then is outputted when the data output command SC is issued, and data averaging step 104 in which a data mean value DM at a cycle NT is outputted by computing from outputted prescribed number N of times and the data addition result value SIGMA based on equation DM=SIGMA/N.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for removing noise from analog data and an apparatus for removing noise from analog data.

0002

2. Description of the Related Art Conventionally, analog data is digitized via an A/D converter by the method shown in FIG.
It is generally read by a microcomputer, etc.

0003

However, in this case, the influence of noise on the analog circuit is definitely expressed numerically. (FIGS. 7 and 8) When analog data containing noise is digitized and used for calculations, the result is that the data varies widely. To remove this noise, capacitors, noise filters, shields, etc. are usually used.
Countermeasures have been taken using analog circuits, but the problem is that reliable noise removal is difficult and costly.

An object of the present invention is to provide a method and apparatus that can reliably remove noise from analog data.

[0005]

[Means for Solving the Problems] In order to solve the above problems, the invention according to claim 1 provides a sampling step 101 for sampling analog data DA at a period T, as shown in FIG. a sampling number counting step 102 of counting the number of times n and, when reaching a predetermined number of times N, outputting the predetermined number of times N and a data output command SC;
The sampling data sampled in the sampling step 101 is sequentially added, and when a data output command is output, the data addition step 103 outputs the data addition result value Σ up to that point, and the predetermined number of times N and data that have been output are added. From the addition result value Σ, the data equality DM in the period NT can be calculated using the following formula.

[0006]

[Math 7]

The data averaging step 104 calculates and outputs data based on . The invention according to claim 2 provides a sampling means 111 for sampling the analog data DA at a period T;
When the number of sampling times n in
A sampling number counting means 112 that outputs C , and a data addition means 113 that sequentially adds the sampling data sampled in the sampling means 111 and, when a data output command is output, outputs the data addition result value Σ up to that point. and the predetermined number of times N
From the data addition result value Σ, the data average value DM in the period NT can be calculated using the following formula.

[0008]

[Math. 8]

The data averaging means 114 calculates and outputs data based on . The invention according to claim 3 is a measuring device comprising a data measuring means and a data outputting means, wherein the data outputting means includes a sampling section 111 that samples the analog data DA calculated by the data measuring means at a period T; The number of samplings n in the section 111 is counted, and a predetermined number of times N
When it reaches this predetermined number of times N and data output command SC
a sampling number counting section 112 that outputs the data, and a data addition section 113 that sequentially adds the sampling data sampled in the sampling section 111 and outputs the data addition result value Σ up to that point when a data output command is output. , from the predetermined number of outputs N and the data addition result value Σ, the data average value DM in the period NT is calculated using the following formula.

0010

[Math. 9]

Data averaging unit 1 which calculates and outputs based on
14. The invention according to claim 4 is:
In a voltmeter including a voltage value measuring means and a voltage value outputting means, the voltage value outputting means includes a sampling section 111 that samples analog voltage data DA measured by the voltage value measuring means at a period T; Count the number of sampling times n, and perform a predetermined number of times N.
When it reaches this predetermined number of times N and data output command SC
a sampling number counting section 112 that outputs the data, and a data addition section 113 that sequentially adds the sampling data sampled in the sampling section 111 and outputs the data addition result value Σ up to that point when a data output command is output. , from the predetermined number of outputs N and the data addition result value Σ, the voltage data equality DM in the period NT can be calculated using the following formula.

0012

[Math. 10]

Data averaging unit 1 that calculates and outputs based on
14. The invention according to claim 5 is:
In an ammeter including a current value measuring means and a current value outputting means, the current value outputting means includes a sampling section 111 that samples analog current data DA measured by the current value measuring means at a period T; Count the number of sampling times n, and perform a predetermined number of times N.
When it reaches this predetermined number of times N and data output command SC
a sampling number counting section 112 that outputs the data, and a data addition section 113 that sequentially adds the sampling data sampled in the sampling section 111 and, when a data output command is output, outputs the data addition result value Σ up to that point. , from the predetermined number of outputs N and the data addition result value Σ, the current data average value DM in the period NT can be calculated using the following formula.

[0014]

[Math. 11]

Data averaging unit 1 that calculates and outputs based on
14. The invention as set forth in claim 6 provides a temperature measuring means for measuring the temperature of the object to be measured and outputting analog temperature data, a data converting means for converting the analog temperature data into digital temperature data, and a preset digital temperature data. A temperature adjustment device comprising: a control means for comparing the set temperature data and outputting a control signal according to the comparison result; and a temperature adjustment means for adjusting the temperature of the object to be measured based on the control signal. , the data conversion means includes a sampling section 111 that samples the analog temperature data DA at a period T, and a sampling step 11.
1, and when a predetermined number N is reached, a sampling number counting section 112 outputs the predetermined number N and a data output command SC, and the sampling data sampled in the sampling section 111 are sequentially added. , when a data output command is output, the data addition unit 113 outputs the data addition result value Σ up to that point, and calculates the temperature data average in the period NT from the predetermined number of outputs N and the data addition result value Σ. The value DM is expressed as

[0016]

[Math. 12]

Data averaging unit 1 that calculates and outputs based on
14.

[0018]

[Operation] Normal data sampling is performed as shown in FIG. 8, and the influence of noise shown in FIG. 7 appears prominently, causing data variations Dp, Dq, Dr, etc., but the sampling period T shown in FIG. If the sampling period is sufficiently faster than the required period in the system, for example, a sampling period of 1 second/time is sufficient for the system, but if sampling can be performed at 0.1 second/time, the time Sequentially add the data during the time of NT (10T in this case) to obtain ΣDi, and using this added value,

[
0019

[Math. 13]

Calculate . By using this average value DM as sampling data with a period NT as shown in FIG. 5, the influence of noise can be removed and data variations can be reduced.

[0021]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below with reference to the drawings. First Embodiment FIG. 2 shows a first embodiment of the present invention. This embodiment is claim 1
An example in which the described invention is applied to a data sampling flowchart is disclosed. Compared to the conventional data sampling method shown in FIG. 6, this embodiment sequentially adds data after normal sampling (step 202).
Step 203) When the number of samplings reaches N=10 (Step 204), the addition result ΣDi
is divided by N and averaged (step 205), and the average value

00
22]

[Math. 14]

The difference is that the average value DM is obtained and stored as data (step 206). Second Embodiment Next, a second embodiment of the present invention will be described. This embodiment discloses an example in which the invention according to claims 2, 3, and 6 is applied to a temperature control device.

As shown in FIG. 3, this temperature control device 9 includes a CPU 1, a ROM 2, a RAM 3, an A/D converter 4, an analog amplifier 5, a multiplexer 6,
It includes a heating section 7 and a temperature sensor 8. The heating unit 7 is installed in a water tank A filled with water. A temperature sensor 8 for temperature measurement is installed in the water of the water tank A, converts water temperature data into a voltage value, and outputs the voltage value to the multiplexer 6. The multiplexer 6 switches data from each sensor according to a command from the CPU 1 and outputs it to the analog amplification section 5.

The analog amplifying section 5 compares the input voltage value with a comparison reference value, and detects a value exceeding the reference value (in this example,
The difference value when the water temperature becomes lower than the reference water temperature) is extracted, amplified, and output to the A/D converter 4. The A/D converter 4 converts the analog differential output extracted by the analog amplifier 5 into a digital value and sends it to the CPU 1. C.P.
ROM2 and RAM3 are connected to U1. C
The PU 1 calculates a data average value from the digital value output from the A/D converter 4 using the calculation program shown in FIG. 2 stored in the ROM 2. Intermediate results of calculations etc. are stored in RAM3. The CPU 1 issues a command to the heating unit 7 based on the digital value indicating the averaged temperature drop to heat the water tank A and raise the water temperature in the water tank A to a constant value.

FIG. 4 is a diagram showing the configuration of the analog amplification section in FIG. 3. This analog amplification section 5 is composed of a comparator section that compares the voltage value VACT inputted from the temperature sensor 8 with a comparison reference voltage VREF, and a buffer amplifier section that operates as a buffer amplifier for the differential output exceeding the reference value. ing. The input voltage VACT takes values in the range of 133.8 to 582.8 mV. Also, here, R1 to R4 are 200kΩR5 is 300kΩ
kΩ, VR1 is set to 200Ω, and VR2 is set to 3kΩ.

In FIGS. 3 and 4, the input analog voltage level is as low as about 1.3 mV/° C., and since the distance between the temperature sensor 8 and the operational amplifier 10 is 1 m or more, it is easily affected by noise. The sampling period of each channel according to the program is approximately 1 msec, but the change in temperature control output does not need to be so fast, so Figure 2
The average of 10 sampling data was used as data using the program. In the circuits shown in FIGS. 3 and 4, in the conventional method, the variation due to noise in the sampled data was about 3°C (data read through the A/D converter), but in this embodiment, the variation due to noise is about 10°C. It was found that by averaging the sampling data of 2 times, the result was approximately 1°C, which was found to be effective in removing noise.

Here, the CPU 1, ROM 2, RAM 3, and A/D converter 4 correspond to the data noise removing device according to claim 2. In addition, CPU1, ROM2,
The RAM 3, A/D converter 4, analog amplification section 5, multiplexer 6, and temperature sensor 8 correspond to the measuring device according to claim 3. Note that the present invention is applicable not only to the temperature adjustment device as in this embodiment, but also to the voltmeter according to claim 4, the ammeter according to claim 5, or other measuring devices. In the case of such diversion, the invention can be understood by adapting the corresponding data to the data of the respective device.

[0029]

[Effects of the Invention] As explained above, according to the present invention,
By performing data processing by software rather than by hardware, analog data noise can be reliably removed, and variations in data after A/D conversion can also be removed, which is an advantage.

[Brief explanation of the drawing]

FIG. 1 is a diagram explaining the principle of the present invention; FIG. 1(A) shows a data noise removal method, and FIG. 1(B) shows a data noise removal device.

FIG. 2 is a flowchart showing the configuration of a sampling method according to the first embodiment of the present invention.

FIG. 3 is a diagram showing the configuration of a temperature control device according to a second embodiment of the present invention.

FIG. 4 is a diagram showing the configuration of an analog amplification section in FIG. 3;

FIG. 5 is a diagram illustrating the state of data processed according to an embodiment of the present invention.

FIG. 6 is a flowchart diagram illustrating a conventional sampling method.

FIG. 7 is a diagram showing analog data including noise.

8 is a diagram showing the state of data when the data in FIG. 7 is sampled at a period T; FIG.

[Explanation of symbols]

1...CPU 2...ROM 3...RAM 4...A/D converter 5...analog amplification section 6...multiplexer 7...heating section 8...temperature sensor 9...temperature adjustment device 10, 11...operational amplifier 100...data noise removal method 101...sampling Step 102...Sampling number counting step 103...Data addition step 104...Data averaging step 110...Data noise removal device 111...Sampling means 112...Sampling number counting means 113...Data addition means 114...Data averaging means 201-206...Step 301- 303...Step A...Water tank DM...Average value R...Resistance SC...Data output command VR...Variable resistance

Claims (6)

[Claims] 1. A sampling step (101) of sampling analog data (DA) at a period T;
The number of sampling times (n) in the sampling step (101) is counted, and when a predetermined number of times N is reached, the predetermined number of times (N) and a data output command (SC) are counted.
sampling count step (102
) and the sampling data sampled in the sampling step (101), and when the data output command (SC) is output, the data addition step (103) outputs the data addition result value Σ up to that point. ), a data averaging step (104
); and a data noise removal method. 2. A sampling means (111) that samples the analog data (DA) at a period T, and counts the number of sampling times (n) in the sampling means (111), and when a predetermined number N is reached, the predetermined A sampling number counting means (112) for outputting the number of times (N) and a data output command (SC) and the sampling data sampled by the sampling means (111) are sequentially added, and the data output command (SC) is outputted. Then, from the data addition means (113) that outputs the data addition result value Σ up to that point, the outputted predetermined number of times N, and the data addition result value Σ, the data average value DM in the period NT is calculated as follows. A data noise removal device characterized by comprising: data averaging means (114) that calculates and outputs the calculation based on the following formula [Equation 2]. 3. In a measuring device comprising a data measuring means and a data outputting means, the data outputting means receives analog data (DA) calculated by the data measuring means.
) sampling section (11
1) and the number of sampling times (n) in the sampling section (111) are counted, and when a predetermined number of times N is reached, the predetermined number of times (N) and the data output command (SC) are counted.
) and the sampling data sampled in the sampling unit (111) are sequentially added, and when the data output command (SC) is output, the data addition result up to that point is a data addition unit (113) that outputs the value Σ;
The predetermined number of times N outputted and the data addition result value Σ
a data averaging unit (114) that calculates and outputs the data average value DM in the period NT based on the following formula [Equation 3];
A measuring device characterized by having: 4. A voltmeter comprising a voltage value measuring means and a voltage value outputting means, wherein the voltage value outputting means receives analog voltage data (DA) measured by the voltage value measuring means.
) sampling section (111
) and the number of sampling times (n) in the sampling section (111) are counted, and when a predetermined number of times N is reached, the predetermined number of times (N) and a data output command (SC) are counted.
a sampling number counting section (112) that outputs
a data addition unit (113) that sequentially adds the sampling data sampled in the sampling unit (111) and, when the data output command (SC) is output, outputs the data addition result value Σ up to that point; a data averaging unit (114) that calculates and outputs a voltage data average value DM in a period NT from the outputted predetermined number of times N and the data addition result value Σ based on the following formula [Equation 4];
A voltmeter characterized by having: 5. An ammeter comprising a current value measuring means and a current value outputting means, wherein the current value outputting means receives analog current data (D) measured by the current value measuring means.
A sampling section (1
11) and the number of sampling times (n) in the sampling section (111), and when a predetermined number of times N is reached, the predetermined number of times (N) and the data output command (SC) are counted.
) and the sampling data sampled in the sampling unit (111) are sequentially added, and when the data output command (SC) is output, the data addition result up to that point is a data addition unit (113) that outputs the value Σ;
The predetermined number of times N outputted and the data addition result value Σ
a data averaging unit (114) that calculates and outputs the current data average value DM in the period NT based on the following formula [Equation 5];
An ammeter characterized by having: 6. Temperature measurement means for measuring the temperature of the object to be measured and outputting analog temperature data; and data conversion means for converting the analog temperature data into digital temperature data.
a control device that compares the digital temperature data with preset temperature data and outputs a control signal according to the comparison result; and a temperature adjustment device that adjusts the temperature of the object to be measured based on the control signal. , wherein the data conversion means includes a sampling section (111) that samples analog temperature data (DA) at a period T, and a sampling section (111) that counts the number of sampling times (n) in the sampling step (111). When a predetermined number of times N is reached, a sampling number counting section (112) outputs the predetermined number of times (N) and a data output command (SC), and the sampling data sampled in the sampling section (111) is sequentially outputted. Add and
When the data output command (SC) is output, the data addition unit (SC) outputs the data addition result value Σ up to that point.
113), and a data averaging unit (113) which calculates and outputs the temperature data average value DM in the period NT from the outputted predetermined number of times N and the data addition result value Σ based on the following formula [Equation 6]. 114) and
A temperature control device characterized by having: