JPH0979870A - Measured data memory device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To accurately store abrupt changes and store measured data for a long period in a small-capacity memory by data-compressing micro-values, storing differential values, and preserving the differential values for large amplitudes. SOLUTION: An initial data absolute value memory section 10 stores the measured data of the initial prescribed bit number N as they are, and a difference calculation section 20 calculates the difference between the previous measured data and the present measured data. A compression dictionary section 30 data-compresses micro-values and stores differential values. When the calculated differential value is within the micro-value range of the compression dictionary section 30, a micro-value compression section 40 converts it into a compression bit train in reference to the dictionary section 30. When the calculated differential value is a large value outside the micro-value range of the dictionary section 30, a large-amplitude description section 50 expresses the differential value with the effective bit number within the prescribed bit number and applies a code to it to represent the nonrequirement for the reference to the dictionary section 30. A differential value time series memory section 60 stores the differential values expressed by the compression section 40 and the description section 50 in time series.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improved measurement data storage device for storing time-series data, and more particularly, to an improvement for efficiently compressing data that rarely changes abruptly.

[0002]

2. Description of the Related Art A technique for compressing time-series data to save memory capacity is disclosed in, for example, Japanese Patent Laid-Open No. Hei 4
As disclosed in Japanese Patent Laid-Open No. 236326, there is known one that stores a difference between time series data.

By the way, considering an application for storing measurement data for applications such as temperature control of an electric furnace, the measured temperature changes slowly, so most of the data differences are ±.
It has a small absolute value of about 1 to 2 [degrees]. On the other hand, since the recorder is a recorder, it is important for the recording to accurately follow abrupt changes in later operation analysis and the like.

[0004]

However, in the conventional display format, the number of bits per measurement data is large in order to accurately reproduce a sudden change, and therefore, when storing a slow temperature change, it takes a long time. There is a problem that a large memory capacity is required to record data. The present invention solves such a problem, and an object of the present invention is to provide a measurement data storage device capable of accurately recording a sudden change and storing long-time measurement data in a memory having a relatively small capacity. .

[0005]

Means for Solving the Problems The present invention that achieves the above-mentioned object is to provide a means 10 for storing the measurement data of a predetermined number of bits (N) for the first time as it is, and a difference between the latest measurement data and the current measurement data. A means 20 for calculating, a compression dictionary unit 30 describing a conversion relationship between a predetermined minute value and a compressed bit string defined to be shorter than the predetermined number of bits, and a current difference value calculated by the difference calculating means is a compression dictionary. When the value is a minute value determined by a unit, the minute value compression unit 40 that refers to the compression dictionary unit and converts it into a corresponding compressed bit string, and the current difference value calculated by the difference calculation means are determined by the compression dictionary unit. When it is not included in the minute value, the large-amplitude description unit 5 that expresses the difference value as an effective number of bits out of the predetermined number of bits together with a code indicating that the compression dictionary unit does not require reference
It is characterized by having 0 and means 60 for storing the difference values expressed by the minute value compression section and the large amplitude description section in time series.

[0006]

According to the structure of the present invention, for the first measurement value, the measurement data is stored as it is in the first data absolute value storage unit 10 and the reference value of the difference value is determined. The difference calculation unit 20 obtains the difference between the latest measurement data and the current measurement data. The compression dictionary unit 30 compresses a minute value that frequently appears when the change is slow, such as temperature, by replacing it with a compressed bit string and storing the entire measurement data in the effective bit number. Get the effect of. The small value compression unit 40 converts the current difference value into a specific compressed bit string by referring to the compression dictionary unit. The large-amplitude description unit 50 expresses the measurement data with the number of effective bits or all the number of bits for a large change that is not included in the compression dictionary unit, and attaches a code for distinguishing it from a small value. The difference value time series storage unit 60 stores the difference values expressed by the compression unit for minute values and the description unit for large amplitude in time series.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the drawings. FIG.
FIG. 3 is a configuration block diagram showing an embodiment of the present invention. In the figure, the initial data absolute value storage unit 10 stores the first predetermined number of bits (N; for example, 16 bits) of measurement data as it is. The difference calculator 20 calculates the difference between the latest measurement data and the current measurement data. The compression dictionary unit 30
It describes the conversion relationship between a predetermined minute value (for example, within the range of -5 to +5) and a compressed bit string (for example, 4 bits) defined to be shorter than the predetermined number of bits. Small value compression unit 40
When the difference value of this time calculated by the difference calculation unit 20 is within the range of the minute value described in the compression dictionary unit 30, the compression dictionary unit 30 is referred to and converted into a corresponding compressed bit string.

When the difference value of this time calculated by the difference calculation section 20 is a large value outside the range of the minute value described in the compression dictionary section 30, the large amplitude description section 50 sets this difference value to a predetermined bit. The compression dictionary unit 3 is represented by a valid bit number of the number and is given a code for distinguishing it from the compressed bit string.
0 indicates that reference is unnecessary. For example, two types of 8-bit width and 16-bit width are prepared as effective bit strings. Then, the data represented by 8 bits with a sign is represented by 8 bit data code + 8 bit data. Specifically, in the case of a plus sign, 00 to 7F (127), and in the case of a minus sign, F
In the range from F to 80 (-128), the range defined by the compression dictionary unit 30 is excluded. Data that is signed and cannot be represented in 8 bits is represented by 16-bit data code + 16-bit data. Specifically, the range from 0080 to 7FFF (32767) for the positive code and the range from FF7F to 7FFF (-32768) for the negative code is targeted. The difference value time series storage unit 60 stores the difference values expressed by the small value compression unit 40 and the large amplitude description unit 50 in time series.

FIG. 2 is a diagram showing an example of the compression dictionary unit 30.
(A) is a code indicating that the effective bit string is 8 bits and 16 bits, (B) is a 4-bit compressed bit string, (C) is a 6-bit compressed bit string, and (D) is a 5-bit compressed bit string. In addition, for example, in the display of {0xb, 4, 0xc}, etc., "0x" is a display showing 16 displays in C language, "0xb" in the first column is the value before conversion, and "4" in the second column. Indicates the number of bits after conversion, and “0xc” in the third column indicates the value after conversion.

In FIG. 2A, "0xb" is a code indicating that the effective bit string is 8 bits, and "0xc" is a code indicating that the effective bit string is 16 bits. In FIG. 2B, +
For 11 numbers from 5 to -5, a 4-bit compressed bit string is defined on a one-to-one basis. Incidentally, there are the following three as the 4-bit code of the compressed word in addition to the 13 in the table, but they are not used as the 4-bit compressed bit string for the following reason. "0xf" is a prohibited word in order to clarify the break of each data after conversion and to enable the reverse conversion. Since "0x0" is used as a 6-bit compressed bit, if it is used as a 4-bit compressed bit,
It becomes indistinguishable. Therefore, in order to clarify the break of each data after conversion and enable the reverse conversion, the word is prohibited as a 4-bit compressed bit string. "0x1" is also a prohibited word as a 4-bit compressed bit string for the same reason as above.

In FIG. 2C, +10 to +6 and -6
A compressed bit string of 6 bits is defined on a one-to-one basis for eight numbers from -8 to -8. In FIG. 2D, -10
A compressed bit string of 5 bits is defined on a one-to-one basis for the two numbers, and -9. In this case, the reason why only two compressed bit strings of 5 bits are used is that the effect of data compression is higher than that when a compressed bit string of 6 bits is used.

The operation of the apparatus thus configured will be specifically described. FIG. 3 is a diagram for explaining how the difference value and the compressed bit string or effective bit string are determined for the six measurement data. First measurement data "123"
For (007B), the measured value is stored as it is as the initial value in the second column. Since this initial value can be represented by 8 bits, the numerical value "7B" is stored in the bit string format following the code "0xc" for 8-bit display. For the second measurement data “125” (007D), “2” is calculated as the difference value in the second column, and the minute value compression unit 40 refers to the compression dictionary unit 30 and corresponds to “0xe”. "Is remembered.

Third measurement data "100" (006
4), "-25" (F
FE7) is calculated, and this value can be represented by 8 bits in the large amplitude description section 50.
The numerical value "E7" is stored in a bit string format following "xc". For the fourth measurement data "-30" (FFE2), the difference value is "-130" (FF7E) in the second column.
Is calculated, and in the large-amplitude description unit 50, since this value is a value to be expressed in 16 bits, the code "0 for 16-bit display"
The numerical value "FF7E" is stored in the bit string format following x2 ". For the fifth measurement data" -33 "(FFDF), the difference value is" -3 "(FFFD) in the second column.
Is calculated, and the minute value compression unit 40 refers to the compression dictionary unit 30 and stores “0x8” corresponding to “fd”. For the sixth measurement data "174" (00AE),
In the second column, "+207" (00CF) is calculated as the difference value, and in the large-amplitude description unit 50, this value is a value that should be expressed in 16 bits, so the code for displaying 16 bits is "0x2".
Then, the numerical value "00CF" is stored in the bit string format. Hereinafter, the same calculation is sequentially performed on the read measurement data.

FIG. 4 is a diagram for explaining the type of the compression dictionary unit 30. The upper column shows a set of decimal display and hexadecimal display. The compression for small values is shown in (a) to (d). The division of the part 40 and the large amplitude description part 50 is shown. (A) is shown in Figure 2.
Corresponding to the compression dictionary section of, the minute value compression section 40 is in charge of the range from 0 to ± 10, and the large amplitude description section 50 is in charge of ± 11 or more. To describe the details of the inside of the large amplitude description section 50, an effective bit string of 8 bit width is used for ± 11 to + 127 / −128, and an effective bit string of 16 bit width is used for + 128 / −129 or more. .

(B) is a slightly modified version of the compression dictionary section of FIG. 2, and uses a 5-bit compressed bit string −10 and −.
For the two numbers 9 as well, a 6-bit compressed bit string is used. Since it is sufficient for the numerical value before conversion and the compressed bit string after conversion to have a one-to-one correspondence, the contents of the compression dictionary unit 30 are only 4 bits and 6 bits, which is an ideally simple structure. In (c), only the 4-bit compressed bit string in the compression dictionary part of FIG. 2 is left in the compression dictionary part 30, and for the 5-bit and 6-bit compressed bit strings, the 8-bit width of the large amplitude description part 50 is effective. It is a bit string. As a result, the compression dictionary unit 3
Since the contents of 0 are simple and the conversion and the inverse conversion can be performed at high speed, it is suitable for high speed storage operation and read operation. In (d), the structure of the large-amplitude description part 50 is simplified, and the effective bit string having an 8-bit width is also in charge of the effective bit string having a 16-bit width. In this way, since there are only two types of storage of measurement data, it is suitable for high-speed storage operation and read operation.

FIG. 5 is a block diagram showing the configuration of another embodiment of the present invention. With the structure of FIG. 1 alone, the measurement data having a slow change such as the temperature measurement is measured relatively frequently, and when the difference value between the adjacent measurement data becomes small, the data compression effect can be obtained. However, if the measurement interval is extremely long even for measurement data that changes frequently due to noise superposition or measurement data that changes slowly, the difference value between adjacent measurement data is large. In the large-amplitude description unit 50, the code for displaying the width of the effective bit string is added, so that the total number of stored bits may increase. Then, there was a problem that the initial purpose of data compression could not be achieved.

In FIG. 5, the normal storage unit 10 is added to the apparatus of FIG.
0, memory bit number operation units 70 and 80, and compression determination unit 9
0 is attached. The normal storage unit 100 stores the input measurement data of a predetermined number of bits as it is. The storage bit number calculation unit 70 calculates the total number of bits stored in the difference value time series storage unit 60. At this time, the number of bits stored in the initial data absolute value storage unit 10 is also taken into consideration. The storage bit number calculation unit 80 calculates the total number of bits stored in the normal storage unit 100. The compression determination unit 90 compares the total bit numbers of the storage bit number calculation units 70 and 80 of both of them, and when the total bit number stored in the difference value time series storage unit 60 becomes large, the difference value time series is calculated. The storage in the 60th storage unit is disabled, and the storage in the normal storage unit 100 is enabled. This prevents the total number of bits required for storage from unnecessarily increasing, and also eliminates the work of restoring the measurement data by referring to the compression dictionary unit 30 when restoring the measurement data. Can be done easily.

FIG. 6 is a block diagram showing the configuration of an apparatus for restoring the data compressed by the apparatus of FIG. The data-compressed measurement data is stored in the initial data absolute value storage unit 10 and the difference value time series storage unit 60. Also, since the compression dictionary unit 30 has a data compression conversion format,
The conversion format for performing reverse conversion from this conversion format is the restoration dictionary unit 12
It is described in 0. The individual relative value identification unit 110 reads out the bit string stored in the difference value time series storage unit 60, identifies each data, and determines whether the value of this data is a minute value or a large amplitude. . Small value restoration unit 130
Refers to the decompression dictionary unit 120 and decompresses a 16-bit difference value from a compressed bit string of 4 to 6 bits.

The large-amplitude restoration unit 140 has a code indicating whether the effective bit string is 8 bits or 16 bits and 8/1.
A 16-bit difference value is restored from the 6-bit data.
The individual absolute value restoration unit 150 includes the initial value stored in the initial data absolute value storage unit 10 and the latest difference value time series storage unit 6.
Since the latest measurement data is obtained from the inversely converted difference value of 0, the inversely converted difference value of the current difference value time series storage unit 60 is added to this to restore the current measurement data. The restored measurement data is sent to the time-series data display unit 160, and CRT display or the like is performed.

In the above embodiment, the case where the measurement data has 16 bits has been described as a column, but the present invention is not limited to this, and the bit width of the measurement data is 8 bits.
Various bit widths such as bits and 32 bits are used.
The compression bit string in the compression dictionary unit 30 is 4
Although the case of up to 6 bits is shown, the bit width may be as short as 3 bits, that is, shorter than the bit width of the measurement data. 8 bits / 1 for the large amplitude description section 50
Although the combination of 6 bits is shown, the bit width of the measurement data may be used as it is, or the width of the effective bit string having another intermediate bit width such as 12 bits may be provided.

[0021]

As described above, according to the present invention,
Since the compression dictionary unit 30 is provided and the minute value is data-compressed and the difference value is stored, there is an effect that the storage capacity is small when recording a slow change such as temperature measurement. Also, for large amplitudes that are not recognized as small values, the difference value is stored in a format that saves it.
There is also an effect that the change waveform of the measurement data is accurately recorded. Further, when the total number of bits stored becomes too large as in the embodiment of FIG. 5, the format for storing normal measurement data as it is is used for storage, so that the memory of the data stored in memory is reduced. The effect is that it can be prevented from increasing.

[Brief description of drawings]

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

FIG. 2 is a diagram showing an example of a compression dictionary unit 30.

FIG. 3 is a diagram illustrating how a difference value and a compressed bit string or effective bit string are determined for six pieces of measurement data.

FIG. 4 is a diagram illustrating types of a compression dictionary unit 30.

FIG. 5 is a configuration block diagram illustrating another embodiment of the present invention.

6 is a configuration block diagram of an apparatus for decompressing data compressed by the apparatus of FIG.

[Explanation of Codes] 10 initial data absolute value storage unit 20 difference calculation unit 30 compression dictionary unit 40 small value compression unit 50 large amplitude description unit 60 difference value time series storage unit 70, 80 storage bit number calculation unit 90 compression determination Part 100 Normal storage part

Claims (2)

[Claims] 1. A means (10) for storing the measurement data of a predetermined number of bits (N) for the first time as it is, a means (20) for calculating a difference between the latest measurement data and the current measurement data, and a predetermined minute value. And a compression dictionary section (3) describing a conversion relationship between a compressed bit string defined to be shorter than the predetermined number of bits.
0) and the difference value of this time calculated by this difference calculating means is a minute value determined by the compression dictionary section, the minute value compression section (40) for converting to the corresponding compressed bit string by referring to the compression dictionary section. ) And the difference value of this time calculated by the difference calculating means is not included in the minute value determined by the compression dictionary unit, the difference value is referred to as a predetermined number of bits together with a code indicating that the compression dictionary unit does not need to be referenced. A large-amplitude description part (50) of which the number of valid bits is expressed, and means (60) for storing the difference values expressed by the minute-value compression part and the large-amplitude description part in time series. A measurement data storage device characterized by: 2. A means (70) for calculating the total number of bits stored in the difference value time series storage means according to claim 1, and a normal storage section (100) for directly storing the input measurement data of a predetermined number of bits. (80) for calculating the total number of bits of the difference value) and the total number of bits of the two are compared, and when the total number of bits stored in the difference value time series storage means becomes large, the difference value time series storage is performed. The measurement data storage device according to claim 1, further comprising: a compression determination unit (90) that invalidates the storage of the means and validates the storage of the normal storage unit.