JP2003075205A - Method of recording data - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method of recording data which maximally utilizes the capacity of a storage memory and stores a maximum a mount of data every fixed time intervals. SOLUTION: For sampling waveform data at fixed time intervals, the data recording method changes the sampling time intervals to equal and unequal intervals according to the dynamic and static changes of the data e.g. as shown in Fig. 1. The data are sampled with equal sampling intervals in a greatly changing data range (dynamic changing portions) to obtain precise data and with unequal sampling intervals such as logarithmic or root intervals in a little changing range (static changing portions) to avoid taking in the data uselessly.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a data recording method, and more particularly to a method for realizing a program for sampling waveform data at arbitrary time intervals.

[0002]

2. Description of the Related Art When measuring an electric signal, a physical quantity, etc., a measurement result may be a dynamic change in a certain section and a static change in a certain section.
Usually, the recording interval is made fine in the case of dynamic change, and the coarse time interval is provided in the case of static change. In the case like Figure 1,
If a series of recordings is performed at fine intervals, more data than necessary will be recorded, and if it is performed at coarse intervals, the measurement accuracy will deteriorate. Here, the static change means, for example, that the measured strain amount does not change at all, or even if there is, the range that can be read by an analog or digital indicator does not change very slowly as shown in FIG. Is a dynamic change
It means a large variation that cannot be read on the display, such as a static variation.

Further, in order to measure the change of the waveform data with the passage of time by measuring, for example, vibrations, as shown in FIG. 1, a static change region where the acceleration (physical quantity) hardly changes, and this acceleration It is necessary to obtain a measurement result that has a region of dynamic change in which the value changes rapidly. Therefore, when the time interval of the captured digital data is set to a relatively long time T ₁ as shown in FIG. 2B, for example, a peak region in which the physical quantity such as an electric signal as shown in FIG. However, since the data interval becomes too coarse, it may not be possible to accurately grasp the state of changes in the physical quantity, or the peak position may become ambiguous. On the other hand, as shown in FIG. 2A, when digital data is taken in at a relatively short time interval T ₂ that can show in detail the abrupt change of the peak region, as shown in FIG. In the area of static change, a large amount of almost the same data will be continuous, and the number of data to be fetched will be unnecessarily large.

As described above, conventionally, since the digital data sent from the measuring device is thinned out at regular time intervals and taken in, if this time interval is lengthened, precise analysis will be performed in the peak area of the data. However, if this time interval is shortened, there is a problem that data is wasted in the area of static change (part). Further, even in general two-dimensional or more data, if data of any of the components of the physical quantity of the scalar is thinned out or sampled at equal intervals, other physical quantities are changed with respect to the change of this physical quantity at equal intervals. A similar problem occurs when the degree of change in is significantly different.

[0005]

SUMMARY OF THE INVENTION The present invention has been made in order to solve the above-mentioned conventional problems, and its object is to effectively utilize the capacity of a memory to make a dynamic change and a static change. It is an object of the present invention to provide a method for efficiently recording measurement results in which the above are mixed and recording the change situation of the phenomenon as necessary and sufficient.

[0006]

In order to achieve the above-mentioned object, the first aspect of the present invention is that when waveform data is sampled at a predetermined time interval, the waveform data is sampled according to the state of change of the data. Provided is a data recording method which is performed by changing the sampling time interval into equal intervals and unequal intervals.

Further, according to the second aspect of the present invention, precise data is acquired by sampling at equal intervals in a region where data change is large, and waste is obtained by sampling at unequal intervals in a region where data change is scarce. Provide a data recording method that does not capture data. Here, the unequal intervals are preferably set, for example, logarithmically or in a route.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION A preferred embodiment of the data recording method of the present invention will be described below with reference to the drawings, but the present invention is not limited to this.

<A> Outline of Data Recording Device The present invention mainly uses a known data recording device (measurement system). For example, it is composed of an acceleration and pore water pressure gauge (measurement sensor, measuring means), and a computer (also called a personal computer) installed in a measurement room near the site or in a room such as a laboratory. The personal computer has a built-in hard disk device. By loading predetermined program data stored in the hard disk device into the main memory of the personal computer and operating the CPU based on the program data, the signal input means, storage control means, Also, output means (not shown) is realized.

As described above, the personal computer constitutes the signal input means, the storage control means and the output means, and these elements collect, store and output the measurement results. Specifically, the signal input means takes in the output signal of the accelerometer or the like at an arbitrary time interval. Then, the storage control means writes the output signal of the accelerometer, which is taken in by the signal input means, in the hard disk device. Further, the output means reads the digital data from the hard disk device and outputs the acceleration and the like as a measurement result to a CRT monitor or the like constituting a personal computer in a predetermined format.

Next, the data recording method according to the present invention will be described in detail.

Concretely, in order to thin out the waveform data at an arbitrary time interval and write and display it in the data storage memory or the image memory, <a> selectively every fixed number of waveform data at equal time intervals. This is done by recording or displaying. <B> The initial selection interval is shortened by logarithmic selection, and the selection interval is logarithmically lengthened as time passes. <C> The selection interval is determined according to the desired function data tabulated. In the following description, examples of equal intervals, root intervals, and logarithmic intervals will be described.

<Setting of Static Recording Interval> Data obtained by discretizing the recording time at a constant sampling time interval ΔT can be expressed as follows.

[0014]

[Equation 1]

<Equal interval> The time interval ΔT can be expressed by the following equation (1).

[0016]

[Equation 2]

<Route Interval> The unequal time interval ΔT can be expressed by the following equation (2).

[0018]

[Equation 3]

<Logarithmic Interval> The time interval ΔT can be expressed logarithmically as in the following equation (3).

[0020]

[Equation 4]

When the static recording start time is set to t ₀ = 100 and the time interval is set to ΔT = 1, the recording time t _i by each method is as shown in the table below.

[0022]

[Table 1]

[0023]

[Example] <B> Conditions As one example, a shake table experiment is targeted. As shown in FIG. 3, vibration is performed for 2 seconds 5 seconds after the start of data recording. Then, the vibration is stopped and left for 10 seconds.
Subsequently, vibration is performed for 1 second. After that, the stopped state is maintained for 5 to 60 minutes. It is expected that the acceleration waveform will be as shown in FIG. Here, the excitation is a 10 Hz sine wave.

It should be noted that the total number of recordings is set to less than 1000 times so that there is no trouble in compiling the data (no stress is felt when the graph is written or calculated in the personal computer) (1000 is With extremely low values,
It is a value only as a setting example).

<B> Recording Method Setting Dynamic recording is performed at 100 Hz (0.01 second intervals, that is, 10 times the frequency of the vibration) for 1 second before and after the vibration.
On the other hand, static recording is performed at intervals of 0.1 second (4 seconds), a root interval, and a logarithmic interval in order. Each time interval is ΔT =
Set to 0.1. From these, the recording time that meets the conditions is
Since it can be set by the above equations (1), (2) and (3),
Omitted here.

As described above, in the present embodiment, since it is not necessary to perform measurement at equal time intervals as in the conventional case, the measurement result can be obtained in a short time and the measurement can be performed with sufficient frequency. be able to. Further, since it is not necessary to use a memory device for storing a huge amount of data, it is advantageous in simplifying and downsizing the measuring device or the measuring system.

In the above, the present invention has been described based on the example for the shaking table experiment, but this is just an example, and the present invention is not limited to this example and can be implemented in various forms. can do.

[0028]

Since the data recording method of the present invention is as described above, the following effects can be obtained. <B> According to the data recording method of the present invention, it is possible to obtain data in which the distance between data such as waveforms in a multidimensional space is substantially constant. For this reason, in the region in which the change of one component of the data is small, the interval between other components of the data can be made sufficiently wide, and the amount of data does not become too large. Further, in the region where the former component of the data changes rapidly, the interval of the latter component of the data does not become too wide, so that this data can be analyzed precisely. In other words, by making the details of other components only in the part where the change of one component of the data is large, precise analysis is possible without increasing the amount of data. Therefore, the storage capacity when storing this data And the transmission rate at the time of transmitting this data can be reduced.

<B> Further, since the timing of continuous measurement is determined by the amount of change in data, it is possible to avoid unnecessary data recording even during measurement, and to measure and leak necessary data. Since appropriate continuous measurement of data can be performed, the measuring device or measuring system can be simplified, reduced in size and weight, and portable, and can be efficiently stored and recorded in the recording medium. Furthermore, it is possible to easily realize various data recording devices or measurement systems for monitoring / observation that make use of the high reliability of digital recording / transmission.

[Brief description of drawings]

FIG. 1 is an explanatory diagram showing the concept of a data recording method according to the present invention.

FIG. 2 is an explanatory diagram showing time intervals of data recording corresponding to dynamic changes and static changes in the data recording method according to the present invention.

FIG. 3 is an explanatory diagram showing an example targeted for a shaking table experiment by the data recording method according to the present invention.

[Explanation of symbols]

T ₁ time interval corresponding to a static change T ₂ time interval corresponding to a dynamic change t time or time

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Yukio Shinami             1-25-1 Nishi-Shinjuku, Shinjuku-ku, Tokyo Taisei             Construction Co., Ltd. F term (reference) 2F070 AA02 AA05 CC01 CC08 CC11                       DD05 DD14 FF05 FF08 FF12

Claims (4)

[Claims] 1. A data recording method, wherein when sampling waveform data at a predetermined time interval, the sampling time interval is changed to an equal interval or an unequal interval according to the change state of the data. 2. The area according to claim 1, wherein dense data is acquired by sampling at equal intervals in an area where data change is large, and data is not unnecessarily taken by sampling at unequal intervals in an area where data change is scarce. How to record data. 3. The method according to claim 1 or 2, The unequal intervals are set logarithmically, Data recording method. 4. The method according to claim 1 or 2, Set unequal intervals as root, Data recording method.