JP3094906B2 - Trend graph display - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a trend graph display device for displaying a changing input signal in real time in a recorder or a process control device, and displays a trend from the latest data to the past data over a long period of time. The present invention relates to a trend graph display device.

[0002]

2. Description of the Related Art With the computerization of measurement and control techniques, trend monitors for displaying changes in signals in real time have been put to practical use. FIG. 9 shows the latest data sequentially displayed while scrolling the measured waveform A displayed on the data display device (display) at a constant speed.

[0003]

However, in the above conventional display method, there is a problem that the period that can be displayed at one time is limited by the size (resolution) of the display, and the longer the display time, the lower the time resolution. . For example, the width in the horizontal direction and the width in the vertical direction are 500 × 40 on the display.
When displaying a trend graph with a size of 0 pixels with a time resolution of 0.1 second, the maximum is 0.1 × 500
= 50 (seconds).

The present invention has been made in order to solve the above-mentioned problems of the prior art, and it is an object of the present invention to provide a trend graph display device which displays a trend from latest data to past data over a long period of time. It is the purpose.

[0005]

In order to achieve the above object, according to the present invention, there is provided a display device for displaying a trend of data which changes with the passage of time. Data generating means for generating data for a period, coordinate calculating means for calculating coordinates of the data, and data displaying means for displaying the data based on the calculated coordinates, wherein the coordinate calculating means is a function of the passage of time. It is characterized by sequentially increasing the reduction ratio of the data axis and the time axis indicating the size of the data with the calculation,

According to a second aspect of the present invention, one of the opposite sides of the data display device is set to the full scale of the data corresponding to the reduction of the data axis and the time axis, and the full scale becomes narrower toward the other side. A scale display mark is provided, and the data display device is provided with a time axis mark corresponding to reduction of the data axis and the time axis. ,

According to a fourth aspect of the present invention, the data calculated by the coordinate calculating means is temporarily stored in a display memory, and when the stored data is displayed on the data display device, a plurality of display memories are prepared and used in the present and next times. Data to be displayed is stored, and the display memory is sequentially switched for display. Hereinafter, the present invention will be described in detail based on embodiments.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is an explanatory diagram of a main part block configuration showing an example of an embodiment of the present invention. In the figure, 1
Is a data generating means, which comprises an A / D converter 2 for inputting an analog input signal i and a buffer memory 3. Reference numeral 4 denotes a coordinate calculation means (CPU), and reference numeral 5 denotes a coordinate memory. Reference numeral 6 denotes a data display unit, which includes a drawing processing device 7, a display memory 8, a display (data display device) 9.
It is composed of

In the figure, an A / D converter 2 operates with a clock 2
In synchronization with a, the analog input signal i is sampled and converted into digital data. The data is stored in the buffer memory 3 from the latest data to the past N samples. The coordinate calculation means (CPU) 4 calculates data stored in the buffer memory 3 and stores the data in the coordinate memory 5.

The drawing processor 7 expands the trend graph in the display memory 8 according to the coordinate data from the coordinate memory 5 and displays the trend graph at the coordinates (X, Y) on the display 9. In addition,
In the above configuration, the operation of sampling the analog input signal i and converting it into digital data and the technique of displaying the converted data on the display 9 are known.

FIG. 2 shows an example of a display according to the present invention. As shown in the figure, the upper left corner of the data display device 9 is set as the origin of X and Y, and past data is displayed toward the left side with the right end (x ₀ ) of the screen as the latest data. (Y ₀ )
Indicates a position at 50% of the full scale of the value axis. A is a curve showing the trend of the input signal that changes over time, B is the upper limit, B 'is a straight line indicating where the lower full scale is, H is the vertical width of the screen, W is
Is the full width of the screen.

Next, an embodiment of the present invention will be described with reference to the flowchart of FIG. In step (1), the A / D converter 2 converts data of a predetermined time (or a predetermined number of samples) into digital data and stores the digital data in the buffer memory 3. Clears the contents of the display memory 8. , Two straight lines B and B ′ representing the full scale of the value axis are drawn. This straight line is calculated by the coordinate calculation means 4 according to the following equation.

First, the coordinates of the upper limit of the latest data (upper right corner) are (x ₀ , y ₀ + H / 2), and the coordinates of the oldest data (left side) are ｛x ₀ -W, y ₀ + H. / (2 ・
K)｝. The coordinates of the latest data (lower left corner) of the lower limit are (x ₀ , y ₀ -H / 2), and the coordinates of the lower limit of the oldest data (left side) are ｛x ₀ -W, y ₀ -H / (2 ・
K)｝. Here, K: reduction ratio before N samples (the oldest data of the captured data). The upper and lower coordinates are connected by a straight line to form a full scale display mark on the value axis. This straight line is calculated by a known calculation formula.

, The data index n is set to 0
(Latest data). In the arithmetic processing unit 4
Extracts the data (measured value v) corresponding to the index n from the buffer memory 3 and performs the coordinate calculation according to the following equation: X [n] = X _0- (WK / N) · [n / {1+ (K−1)・ (N / N)}] ... (1) Y [n] = Y _0- (H / F _S ) ・ [v / {1+ (K-1) ・ (n / N)}] ... (2) Where X ₀ , Y ₀ = position of data (0,0) on display W = display width of display in X direction H = display width of display in Y direction E _s = input full scale K = data before N samples (K> 1) The calculated value is stored in the coordinate memory 5.

In the above, it is assumed that n = n + 1. , It is determined that n> N. If NO, return to n = N
Repeat the same operation until. , The coordinate index is set to 0. In the drawing processing device 7
Extracts coordinates (X [n], Y [n]) corresponding to index n and coordinates (X [n _{+ 1} ], Y [n _{+ 1} ]) corresponding to (n + 1) from the coordinate memory 5 and outputs X [n , Y [n] to X [n _{+ 1} ], Y [n _{+ 1} ] are displayed on the display. In (10),
Let n = n + 1. In (11), it is determined that n = N.
If NO, the process returns and the same operation is repeated until n = N.

According to the above-described configuration, the data taken in at the time of display on the apparatus is sequentially increased in time axis and full scale from the new data to the old data, thereby increasing the trend of a larger number of data than before. Can be displayed. FIG. 4 shows a time axis scale line (75%... C,
50%... C ', 25%... "). This time axis scale is expressed by the above-mentioned equation (1). X [n] = X _0- (WK / N) · [n / It can be calculated by using {(1+ (K-1) · (n / N)}].

For example, the width W is 500 mm, the reduction ratio is 3,
When the number of samples is 500, the full scale at the 50% position is: X = 500-{(500/3) / 500}. [250 / {1+ (3-1). (250/500)}] =
125 (mm), and the positions of 75% and 25% are the positions of 62.5 mm and 250 mm. As described above, when the reduction ratio is displayed as 3, for example, 300 samples can be displayed instead of, for example, only 100 samples can be displayed conventionally.

That is, for example, 500 on the X axis and 400 on the Y axis
When displaying 1500 samples of data at a reduction ratio of 3 on a screen having pixels (pixels), the leftmost pixel row includes the oldest data to the third data on the Y-axis (value axis). Compressed to / 3, and the compression state is relaxed toward the right side, and one data is displayed for one pixel at the right end, and the time axis compression ratio becomes zero.

FIG. 5 shows an example in which a trend display for four channels is displayed on one screen. In the figure, the width of the full scale on the vertical axis is divided into 25% units, and the width of 25% is defined as the full scale. It was done. In this case, the Y coordinate is (2)
The value calculated by the equation is ± 1 of the vertical width with respect to the center (y ₀ ).
It is a value obtained by adding either 2.5% or ± 37.5%. FIG. 6 shows an example in which the vertical direction of the screen is displayed as a time axis, and the time axis is shortened from the lower side to the upper side with the origin at the right corner.

FIG. 6 shows a main part of an embodiment according to claim 4. FIG. 1 shows an example in which one display memory is provided. However, when the screen is updated by continuously taking in data, the screen may flicker. In such a case, two or more (two in the figure) display memories 8 may be provided, data to be displayed this time and next time may be separately stored, and the display memories 8 may be sequentially switched and displayed.

[0021]

As described above, according to the present invention,
What is claimed is: 1. A display device for displaying a trend of data that changes over time, comprising: data generating means for generating data for a period to be displayed; coordinate calculating means for calculating coordinates of the data; Data display means for displaying the data on the basis of coordinates, wherein the coordinate calculation means performs calculations by sequentially increasing the reduction ratio of the data axis indicating the size of the data and the time axis over time. In response to the reduction of the time axis, one of the opposite sides of the data display device is set to a full scale, and a full scale display mark or a time axis mark is provided in which the full scale gradually narrows toward the other side. Is temporarily stored in a display memory, and when displaying the stored data on the data display device, a plurality of display memories are prepared and And stores the data to be displayed on the next time,
The display memory is sequentially switched and displayed. As a result, the trend from the latest data to the past data can be displayed over a long period of time, and a flicker-free trend graph display device can be realized.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram of a main part configuration showing an example of an embodiment of the present invention.

FIG. 2 is a diagram showing an example of a display according to the present invention.

FIG. 3 is a flowchart illustrating the present invention.

FIG. 4 is an explanatory diagram showing an example in which a time axis scale line is provided in addition to a full scale scale.

FIG. 5 is a diagram illustrating an example in which trend display for four channels is performed on one screen.

FIG. 6 is a diagram illustrating an example in which a vertical direction of a screen is displayed as a time axis.

FIG. 7 is a diagram showing an example in which a plurality of display memories are provided.

FIG. 8 is an explanatory diagram showing a conventional display example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Data generation part 2 ... A / D converter 3 ... Buffer memory 4 ... Coordinate calculation means 5 ... Coordinate memory 6 ... Data display means 7 ... Drawing processing device 8 ... Display memory 9 ... Data display device (display)

Continuation of the front page (51) Int.Cl. ⁷ Identification code FI G05B 23/02 301 G05B 23/02 301T G09G 5/00 510 G09G 5/00 510C 5/36 510 5/36 510A Int.Cl. ⁷ , DB name) G01R 13/00-13/42 G05B 23/02 301 G09G 5/00 510 G09G 5/36 510

Claims (4)

(57) [Claims] 1. A display device for displaying a trend of data that changes over time, comprising: data generating means for generating data for a period to be displayed; and coordinate calculating means for calculating coordinates of the data. Data display means for displaying the data based on the calculated coordinates, wherein the coordinate calculation means sequentially increases the reduction ratio of the data axis indicating the size of the data and the time axis with the passage of time. A trend graph display device characterized in that the calculation is performed by calculation. 2. A full scale display mark in which one of the opposite sides of the data display device is set to a full scale of data in accordance with the reduction of the data axis and the time axis, and the full scale becomes narrower toward the other side. The trend graph display device according to claim 1, wherein the trend graph display device is provided. 3. The trend graph display device according to claim 1, wherein a time axis mark is provided on the data display device in correspondence with the reduction of the data axis and the time axis. 4. The data calculated by said coordinate calculation means is temporarily stored in a display memory, and when displaying the stored data on said data display device, a plurality of said display memories are prepared and displayed this time and next time. 2. The data to be stored is stored, and the display memory is sequentially switched and displayed.
The described trend graph display device.