JPH02105976A - Automatic determining method for logic diagram display coordinate - Google Patents

Abstract

PURPOSE:To generate automatically a logic diagram in which the flow or a signal is easily grasped by deriving arrangement condition under which logic symbols which are functionally relative are arrayed linearly along the connection of a signal line and determining display coordinates of the logic symbols by utilizing the condition. CONSTITUTION:Connection information on the logic diagram stored in a logic connection information storage device 6 is inputted as to a range indicated by an operator and the arrangement condition of a group of logic symbols which can be arrayed laterally and a group of logic symbols which are arrayed at the uppermost position of the diagram is determined. Then the arrangement coordinates of the logic symbols are found according to the arrangement condition of the logic symbols to determine a display position, the determined arrangement coordinates of the logic symbols are stored in a logic arrangement information storage device 7, and arrangement information on the logic diagram is outputted on a display device 1 to visualize the logic diagram. Consequently, the logic symbols are arranged automatically to generate the logic diagram wherein the flow of the logic signal is easily grasped.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a method for automatically outputting a logic diagram,
In particular, the arrangement of each logic symbol is determined based on connection information and input/output terminal definition information of logic diagrams such as control logic diagrams and block diagrams. This invention relates to a method for automatically determining logic diagram display coordinates that automatically determines the flow of control signals in view of ease of viewing.

[Prior Art] Conventionally, in order to create logic diagrams using a computer interactively, positions on a graphic display screen are specified as input of logic symbol placement information, and logic symbols and connections between them are specified. A technique is used to arrange signal lines that

For example, according to the device described in Japanese Patent Application Laid-Open No. 59-45575, the internal configuration of components such as processors, clocks, registers, etc. is developed in stages into hierarchical drawings, and the developed drawings are used as targets. You can consider more detailed designs and proceed with the design. In this method, one person draws a logic diagram through experience and trial and error, and confirms the function of the logic using the diagram, but this work is monotonous and takes a long time. Furthermore, since it is done manually, input errors such as wiring errors in logic symbol signal lines are unavoidable.

In relation to this, according to recent automatic design methods for logic circuits centered on automatic design technology for semiconductor integrated circuits, for each logic symbol included in the number of logic stages in the order of appearance,
There is a placement optimization technique that uses the degree of congestion of signal lines connecting adjacent logic stages as an evaluation function. According to this, it is possible to automatically determine the display coordinates of the logic symbols in the logic circuit diagram, which makes it easy to clearly understand the number of logic stages.

On the other hand, control logic diagrams and block diagrams used in the design of control systems for industrial plants such as power plants, water and sewage plants, and steel plants are functional diagrams for designing calculation programs and electronic circuits to realize control functions. There is a role as For this purpose, when arranging logic symbols in a logic diagram, it is essential to arrange the logic symbols in a line along the main signal flow so that it is easy to understand the flow of No. 4B. It's coming.

[Problems to be Solved by the Invention] When applying the device according to the above-mentioned prior art to determining the display coordinates of logic symbols in a logic diagram, functionally related logic symbols are aligned in a straight line along signal line connections. The arrangement condition of arranging the signals in the same manner as shown in FIG.

In view of the above-mentioned problems, an object of the present invention is to visualize logic diagrams by aligning functionally related logic symbols along signal line connections when automatically creating a diagram. The object of the present invention is to derive a placement condition of alignment and to provide a method for automatically determining display coordinates of a logic diagram using the condition.

[Means to solve the problem] In order to solve the above problems, in the present invention.

By using the input/output terminals of each logic symbol that are connected to the logic symbol in a straight line horizontally, the connection relationship between adjacent logic symbols can be traced, and logic symbols that can be arranged horizontally in a straight line can be traced. Find a pair,
Next, select a set of logic symbols to be placed at the top position of the diagram, and then sequentially move the logic symbols from the input logic symbol placed at the top position on the input side in logic (connection relationship of logic symbols) to the output side. Determines the display coordinates for multi-input logic symbols.

If an unplaced logic symbol is connected to the input side,
From a set of logic symbols that can be arranged in a horizontal row, unplaced input terminals are searched, and from there the display coordinates of the logic symbols are determined sequentially toward the output side. First place the output terminal side to which unplaced logic symbols are connected on the output side to which logic symbols that can be arranged horizontally in a line with logic symbols are connected, and then start from the output logic symbol whose display coordinates have been determined. It searches for multi-output logic symbols going back to the input side, and if unplaced logic symbols are connected, it sequentially goes to the output side and determines the display coordinates of the unplaced logic symbols. Automatically route signal lines based on placement information and connection information.

[Function] According to the present invention, sets of logic symbols that can be arranged horizontally in a row are determined, and first, the drawing order of these sets is determined sequentially from the input side of the logic. As a result, logic symbols can be automatically arranged, and a logic diagram can be generated that makes it easy to understand the flow of logic signals.

[Example] Hereinafter, an example of a logic diagram display coordinate automatic determination method and a device used therein according to the present invention will be described.

FIG. 1 shows an embodiment of the configuration of an apparatus used in the method for automatically determining coordinates for displaying a logic diagram in this embodiment. The arithmetic processing device 5 is a calculation section 5a.

Logic diagram display coordinate automatic determination procedure storage section 5b, input section 5
c, an image data output section 5d, a logic diagram connection information input section 5e, and a logic diagram arrangement information output section 5f. The calculation unit 5a sequentially calls the processing procedure stored in the logic diagram display coordinate automatic determination procedure storage unit 5b,
The zero image data storage device 3, which executes processing based on the processing procedure, stores coordinate data of logic symbols, which is image data output from the arithmetic processing device 5.

The image display control device 2 reads coordinate data of logic symbols to be displayed from the image data storage device 3 and displays the logic symbols on the display device 1. 4 is an input device, 6 is a logic connection information storage device, and 7 is a logic placement information storage device.

Through processing by the logic diagram display coordinate automatic determination device having the above configuration, a logic diagram is constructed based on the information input by the operator from the human blade device 4, and the result is displayed on the display device 1. Logic symbol arrangement information is stored in the logic arrangement information storage device 7.

Second, an embodiment of the processing procedure according to the present invention executed by the arithmetic processing device 5 will be described. Hereinafter, the processing procedure of this embodiment will be explained step by step.

The operation of the device of this embodiment will be explained.

First, step 8 is a process of inputting the connection information of the logic diagram stored in the logic connection information storage device 6 for the range specified by the operator. Step 9
is a process of determining logic symbol arrangement conditions for a set of logic symbols that can be arranged in a horizontal line and a set of logic symbols that can be arranged at the top position in one diagram;
Step 10 is a process of determining the placement coordinates of the logic symbol based on the logic symbol placement conditions and determining the display position. Step 11 is storing the determined display coordinates of the logic symbol in the logic placement information storage device 7.
Furthermore, this is a process of outputting the layout information of the logic diagram to a display device and visualizing the logic diagram.

FIG. 3 shows the logic connection state by a directed graph regarding a part of the logic connection information specified by the operator in step 8, and shows the logical connection relationship between logic symbols. Circles indicate logic symbols, and arrows indicate connection relationships.6For example, symbol A is connected to symbol C, and symbol C is further connected to symbol B and symbol D. FIG. 4 is a diagram showing an example of the storage format of data regarding the symbol of the logic diagram specified by the operator in step 8. , (The data in FIG. 4 is stored in advance in the logic connection information storage device 6.) In this example, for each symbol included in the logic diagram shown in FIG. This is what I remembered. for example.

Connect symbol A to symbol C at the output terminal.

Further, symbol C is connected to symbol A and symbol B at the input terminal, and connected to symbol D at the output terminal. In the following, the details of this example will be explained using data of logic symbols in the connection state shown in FIG. 3 and stored in the storage format shown in FIG. 4 as objects for determining display coordinates of logic symbols. Explain.

Next, in step 9, logic symbol arrangement conditions are determined regarding a set of logic symbols that can be arranged horizontally in a row and a set of logic symbols that can be arranged at the top position in FIG.

FIG. 5 shows that in step 9, symbols that are input and output of logic (the connection relationship between logic symbols is called logic) are extracted in order to find a set of logic symbols that can be arranged in a horizontal line. This shows the processing procedure, in which the logic symbol data shown in FIG. 4 is searched and logic symbols without input/output terminal numbers are extracted. By the process shown in FIG.

As the initial value of a set of logic symbols that can be arranged in a horizontal line (this is called an aligned logic symbol set),
A list consisting of 6 aligned logic symbol sets [(A)
, (B), (F), (H), (J) and (
P)] is obtained. That is, it is a list of sets of symbols that have only input terminals or only output terminals.

Note that each symbol group is represented by parentheses as a notation, and a collection of symbol groups is referred to as a list.

In addition, in FIG. 5, i indicates a pointer in FIG.
j indicates a pointer in the list of aligned logic symbol sets (FIG. 7).

FIG. 6 shows that in step 9, the list of six aligned logic symbol sets obtained above is used as the initial value, and the fourth
This figure shows a processing procedure for searching the logic symbol data shown in the figure and finding a set of logic symbols that can be arranged horizontally in a single line. This process searches logic symbol data, finds logic symbols that are connected to each other via a terminal with an input terminal number of 1 and a terminal with an output terminal number of 1, and selects a symbol group in a list of aligned logic symbol groups. The above processing is repeated until the connection relationships of logic symbols that are connected to each other via the terminal whose input terminal number is 1 and the terminal whose output terminal number is 1 are exhausted. In FIG. 6, i indicates a pointer in FIG. 4, and j indicates a pointer in FIG. 7. The parameter FQ of this process is! 1! This detects that a connection relationship for adding a logic symbol to the symbols in the list of column logic symbol sets is no longer found. (FQ=1
means that the connection relationship added above can still be found,
Fu=O means it is no longer found.

) From the list of aligned logic symbol pairs obtained by the above process, one of the overlapping symbol pairs is deleted to obtain a set of logic symbols that can be arranged horizontally in one line.

FIG. 7 is a list of aligned logic symbol sets finally obtained from the logic symbol data shown in FIG.

Also, in the final stage of step 9, when determining the set of logic symbols to be placed at the top position of the diagram, ! From the list 1- of logic symbol sets in one column, extract the symbol set whose first and last logic symbols do not have input and output terminal numbers and are input and output of the logic diagram,
It shall be placed at the top of the diagram. With this process,
A symbol set (ACDGH) is selected from the list of aligned logic symbol sets shown in FIG. 7, and this becomes the logic symbol to be placed at the top position in the figure.

Next, in step 10, the arrangement coordinates of the logic symbols are determined based on the logic symbol arrangement conditions obtained in step 9. In step 10, the elements of the aligned logic symbol list are searched in order from the input end of the logic symbol placed at the top of the diagram, and the display coordinates of the logic symbols are determined at predetermined intervals. Also, during this search, when targeting logic symbols with multiple inputs,
If an unplaced logic symbol is connected to the input side,
From the list of sorted logic symbol sets, unplaced logic input symbols are found, and from there, the display coordinates of the logic symbols are determined in order of the elements of the sorted logic symbol list, sequentially facing the output side. At this time, each time a multi-input logic symbol appears, a position that does not overlap with an already placed logic symbol is searched to determine the display coordinates of the unplaced logic symbol. On the other hand, in the middle of the above search, when targeting multi-output logic symbols, if an unplaced logic symbol is connected to the output side, the output terminal side with the output terminal number 1 is placed first. Afterwards, using the unplaced logic symbol connected to the output terminal of a multi-output logic symbol whose output terminal number is 2 or higher as a new starting point, sequentially face the output side and set the display coordinates of the unplaced logic symbol. decide. In this way, the processing procedure of step 10 is: (1) Connecting from the input side of the logic to the input terminal of the logic symbol.

A procedure for recursively determining the display coordinates of all logic symbols that involve logic merging; It consists of a procedure for determining the

FIG. 8 shows an overview of the processing procedure executed recursively in step 10.

The detailed processing procedure of the first half 15 of the processing procedure shown in FIG. 8 is shown in FIG. When the process of step 10 is started, the set of aligned logic symbols set in step 17 is the set of logic symbols to be placed at the top position in the diagram. After the processing of steps 18, 19 and 20, regarding the logic symbols belonging to the aligned logic symbol group,
Display coordinates are determined at a predetermined interval ΔX in the direction of the X coordinate axis. In steps 22 and 23, it is determined whether the device has multiple input/output terminals. If logic symbols connected to each other by a single input/output terminal are to be placed next, the aligned logic symbol set is updated in step 26,
Return to step 18.

In contrast, step 24 in the process shown in FIG.
In this step, the arrangement of logic symbols is newly determined from the input side for the aligned logic symbol set including the logic symbols connected to the input terminals. Each time step 24 is called, the Y coordinate value Y, which is the reference for arranging the logic symbols horizontally, is updated as Y0←Y, ~ΔY using the predetermined rJJ distance in the Y coordinate axis direction - ΔY. do. Thereby, logic symbols can be arranged so that signal lines do not intersect on the input side of a logic symbol having a plurality of input terminals. According to step 24,
After the display positions of all the logic symbols at the input end of the logic symbol having multiple input terminals are determined, in step 27, the aligned logic symbol set including the logic symbols having multiple input terminals is updated, and then one set of aligned logic symbols is updated. Returning to the step of determining the display coordinates of the logic symbols included in the

Furthermore, if a logic symbol with multiple output terminals appears in the determination at step 23, then at step 25, the logic symbol is stacked □ (first
-in 1st-out storage device), updating the aligned logic symbol set including logic symbols having a plurality of input terminals in step 27, and subsequently determining the display coordinates of the logic symbols included in the set. Return to Every time a logic symbol included in a set appears that has multiple output terminals, that logic symbol is stored on the stack.

The detailed processing procedure of the second half 16 of the processing procedure shown in FIG. 8 is shown in FIG. The process shown in FIG. 10 takes out the logic symbol stored in the stack in step 25 from the logic output side to Jm, and determines the display coordinates of the unplaced logic symbol connected to the output terminal.

In step 30.

New placement of logic symbols is determined from the first element of the set of aligned logic symbols that includes logic symbols connected to the logic symbol taken out from the stack. The process in step 30 is executed by calling the process shown in FIG.

As above, sequentially from the input side of the logic.

The process of determining the display doctor coordinates of the logic symbols is completed by determining in step 21 of FIG. 9 that the set of logic symbols placed at the top position of the diagram is empty.

The process of determining the display coordinates of logic symbols is explained by taking as an example the case where the process of step 10 above is applied to the logic symbol data shown in FIG. 4 and the list of aligned logic symbol sets shown in FIG. , explained below.

(a) A set of aligned logic symbols (ACDGH) is arranged from logic symbol A, which is the first element, to logic symbol H, which is the last element, in order at the top of the diagram.

(b) Whenever logic symbol C is placed, logic symbol B in the aligned logic symbol group is placed below logic symbol A.

<C> Place logic symbol C.

(d) Search for an aligned logic symbol set (FE) that includes logic symbol E connected to the input terminal of logic symbol D, and place logic symbols F and E under logic symbol B before placing logic symbol D. .

(e) Place logic symbol D.

(f) Place logic symbol G. logic symbol G
stored on the stack.

(g) Place logic symbol H.

(h) Take out logic symbol G from the stack.

(i) Search for logic symbol E connected to the output terminal of logic symbol G.

(j) Search for an aligned logic symbol set (PK) that includes logic symbol K connected to the input terminal of logic symbol A, and before placing logic symbol Placed below.

(k) Search for an aligned logic symbol set (IJ) that includes logic symbol I, starting with logic symbol I and logic symbol 1. Place them in the order of J below the placed logic symbol H.

Finally, in step 11, the display coordinates of the logic symbol and the data of the display figure are written into the image data storage device 3 via the image data output section, and the mouth-knock symbol is displayed on the display device 1 in the one-image display device 2.

FIG. 11 shows an example of a display image in which a logic diagram in which display coordinates of logic symbols are determined by the processes (a) to (k) described above is displayed on the display device 1. Furthermore,
The display coordinates of the logic symbols are stored in the logic arrangement information storage device together with the connection information as arrangement information of the logic diagram. FIG. 11 shows an example of a logic diagram display screen displayed on the display device 1.

In addition to displaying the logic diagram on the display device of the device of the present invention, the arrangement information of the logic diagram stored in the logic arrangement information storage device 7 can be used as data to an automatic wiring display device for signal lines between logic symbols. For the purpose of use, the logic diagram layout information may be stored in the logic diagram layout information storage device 7 as a drawing command to these external display devices. The data stored in the logic arrangement information storage device 7 is used as input data to a device for determining the arrangement of signal line paths between logic symbols and displaying the arrangement. At this time, since logic symbol placement information is given in the form of a drawing command to a device for displaying logic symbols and signal lines, the placement information in the storage device 7 includes the position coordinates of the logic symbols and their positions. Alternatively, it may be stored in combination with a drawing command for displaying a figure specific to the type of logic symbol.

According to the embodiments of the present invention described above, logic symbols can be arranged so that signal lines do not intersect on the input side of logic symbols having a plurality of input/output terminals.

In the above embodiment, the data to be stored in the logic connection information storage device 6 is created in advance before implementing the method according to the present invention. The data stored in the storage device 6 describes the connection relationships between logic symbols, and the method for creating it is: ■ Using a so-called editor such as a file editing program,
Either manually enter characters and numbers from the keyboard as data for each pointer shown in Figure 4 into the storage device, or use a coordinate input device on the screen displaying the graph state of the logic symbol shown in Figure 3. There is a method that uses ``to add connection lines'' to create connection information between logic symbols. In particular, method (2) will be explained below.

Conventionally, CAD devices include a display screen that displays a logic diagram, and a coordinate input device that generates coordinate value data when an arbitrary position on the display screen is specified.
An interactive method of using a computer is used in which a point, a line segment, a symbol, etc. is displayed at a position specified by an operator, and the coordinate values of the position are written into a block diagram data storage device.

For example, a coordinate input device collectively referred to as a joystick or a mouse as shown in Document (1) below is used as the input device 4.
Consider the case where it is used for The coordinate input device converts the movement of the operating part operated by the operator into displacement in two orthogonal directions on a plane on the display (in the ffi structure,
An encoder that converts displacement into coordinate value data is connected. Further, the coordinate input device writes data of coordinate values to the arithmetic processing device 5 via the input section 5C and sends one interrupt signal. Until the operator operates the coordinate human power device and sends an interrupt signal to the arithmetic processing unit 5, a designated point, collectively called a cursor, is displayed on the screen of the display device corresponding to the coordinate position designated by the operating part. . This indication point is displayed by a process in which the image display device sequentially reads the coordinate values X and Y on the screen of the display device written in the image data storage unit, and displays a symbol representing the point on the screen of the display device. This is performed by the image display device.

As described above, by specifying the position on the screen of the display device, you can input coordinate values for displaying points, figures, and symbols at the indicated point, displaying line segments connecting multiple indicated points, etc. becomes possible.

On the other hand, after the indicated point is given, the point to the indicated point.

Processing such as displaying figures, symbols, and displaying line segments connecting multiple indicated points can be done by, for example,
Made using computer graphics technology. Further, information for drawing elements of the displayed logic diagram, tangent Vt lines, etc. is stored as data. The processing for this will be explained below.

FIG. 12 shows an example of a screen displayed on the display device during the process of creating elements of a logic diagram.

FIG. 13 shows an example of drawing information for element A shown in FIG. 12, which is obtained as a result of the operator designating the position and drawing the element of the logic diagram.

In the computer graphics technology disclosed in Document (2), data of an image to be displayed is divided and defined into what are collectively called segments as units for one drawing. In this example, in order to draw element A, one segment is defined, and the line segments included therein, the types of characters, and the position coordinate values to be displayed are described.

Furthermore, Fig. 14 and Fig. 15 show examples of displaying points indicated by an operator to draw a connection line connecting two elements of a logic diagram. In this example, the direction from element A to element C is shown. In order to draw a connection line, first point a part of element A using a pointing point as shown in Figure 14, and then draw a part of element C as shown in Figure 15. The same instructions have been given. At this time, according to the graphics input means according to document (2), it is possible to select an already displayed segment using a pointing point.

FIG. 16 shows a display example of connection lines drawn in the above procedure.

Figure 17 shows an example of the drawing information for a segment representing a connecting line drawn in the above procedure. In this example, which of the two end points of the connecting line is selected first to draw the line segment It is also possible to display information regarding

By the means described above, an operator can create a logic diagram and store drawing information of elements and connection lines in the logic connection information storage device 6.

References (1) S1lliaa+ M, Newa+an an
d Robert F, 5proull: Pr1nc
iples of Interactive Comp
uter Graphics.

2nd Ed, McGraw-Hill Int.
Book Co, (1983) ■ F, R, A Hop
Good et al., supervised translation by Hiroyuki Yoshikawa: Computer Graphics Basic Software GKS, Keigaku Publishing (1986) [Effects of the Invention] According to the present invention, when creating a diagram that visualizes logic, functionally related logic can be created. By deriving the arrangement condition of arranging symbols in a line along the signal line connections and using this to determine the display coordinates of logic symbols, it is possible to automatically create logic diagrams that make it easy to understand the flow of signals. There is an effect.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing a device used in an embodiment of the method for automatically determining logic diagram display coordinates according to the present invention, and FIG. 2 shows an example of a processing flow used for automatically determining logic diagram display coordinates in this embodiment. 3 is a diagram showing an example of a configuration regarding a logic diagram, FIG. 4 is a logic diagram showing an example of a data storage format regarding connection information, and FIGS. 5 and 6 are diagrams showing the operation of this embodiment. FIG. 7 is a diagram showing an example of a data storage format regarding connection information in a logic diagram, FIGS. 8, 9, and 1
Figure 0 is an illustrative diagram of the processing flow used in this example,
The figure shows an example of the display screen of the logic diagram obtained in this example, FIG. 12 shows an example of the screen of the display device displayed in the process of creating elements of the logic diagram, and FIG. A diagram showing an example of drawing information for elements of a logic diagram,
Figures 14 and 15 are diagrams showing an example of the display of indicated points by an operator for drawing a logic diagram, and Figure 16 is an example of a screen of a display device displayed in the process of drawing elements of a logic diagram. Figure shown. FIG. 17 is a diagram showing an example of drawing information for connection lines between elements of a logic diagram. 1...Display device 2...Image display control device 3...Image data storage device 4...Input device 5.
... Arithmetic processing unit 6... Logic connection information storage device 7... Logic arrangement information storage device Hiroshi Tani section '771 Fig. 5α: Arithmetic section 5L:L Image data output device 4 units, 71 liters No. 4 Figure 2 Figure 6 Figure 9 Figure 7 District 8 Figure 11 Figure @ 14 Figure 15 Figure 13 District Figure 17

Claims (1)

[Claims] 1. In a logic diagram display coordinate automatic determination method for outputting logic symbols as a logic diagram on orthogonal coordinates based on connection information of logic symbols included in the logic diagram, two or more input terminals or output terminals Match the coordinates in the vertical axis direction in the logic diagram of the logic symbols that can be arranged in a line among the logic symbols that have terminals and the logic symbols that are connected to each other between the input and output logic symbols in the logic symbol connection relationship, and , sequentially determine the coordinates in the horizontal axis direction of the logic diagram at predetermined intervals, and
The vertical axis coordinate of a logic symbol whose coordinates have not yet been determined is connected to a logic symbol that has more than one input terminal or output terminal, so that it does not exceed the lower limit value of the vertical axis coordinate of a logic symbol whose coordinates have already been determined. By deciding
A method for automatically determining display coordinates of logic diagrams, characterized by determining display coordinates of logic symbols. 2. In the logic diagram display coordinate automatic determination method that outputs the logic diagram as a logic diagram on orthogonal coordinates based on the connection information of the logic symbols included in the logic diagram, the input/output terminal of each logic symbol is With input/output terminals connected to logic symbols in a straight line,
Trace the connection relationships between adjacent logic symbols, find a set of logic symbols that can be arranged in a horizontal line, then select the set of logic symbols to be placed at the highest value in the diagram, and then Then, the display coordinates of the logic symbols are determined sequentially from the input logic symbol placed at the highest value on the input side in the logic symbol connection relationship toward the output side, and when a multi-input logic symbol appears, the display coordinates of the logic symbols are determined. When unallocated logic symbols are connected, search for unplaced input logic symbols included in a set of logic symbols that can be arranged in a horizontal line, and sequentially move from the input logic symbol to the output side. When the display coordinates are determined and a multi-output logic symbol appears, it is included in a group of logic symbols that can be arranged in a horizontal line, and can be arranged in a horizontal line with a multi-output logic symbol. After first placing the logic symbols connected to the output side to which the logic symbols are connected, trace back from the output logic symbol to the input side in the logic symbol connection relationship and place the logic symbols connected to the output terminals with unplaced logic symbols. A method for automatically determining display coordinates of a logic diagram, characterized by searching for output logic symbols and sequentially determining display coordinates of unplaced logic symbols starting from a multi-output logic symbol toward the output side. 3. In a method for automatically determining logic diagram display coordinates that outputs logic symbols on orthogonal coordinates as a logic diagram based on connection information of logic symbols included in a logic diagram, connections of logic diagrams stored in a logic connection information storage device are used. a step of inputting information regarding a range designated by an operator; and determining logic symbol arrangement conditions regarding a set of logic symbols that can be arranged horizontally and a set of logic symbols to be arranged at the top position of the logic diagram. a step of determining the placement coordinates of the logic symbol based on the logic symbol placement conditions and determining the display position; storing the determined display coordinates of the logic symbol in the storage device; and further storing the logic diagram placement information on the display device. A method for automatically determining coordinates for displaying a logic diagram, the method comprising the steps of: 4. When determining the arrangement coordinates of logic symbols, the coordinate values in the vertical axis direction, which serve as the reference for arranging multiple sets of logic symbols that can be arranged horizontally in a single line, are set at predetermined intervals in the vertical axis direction. 4. The method for automatically determining logic diagram display coordinates according to claim 3, wherein the determination is made at a time. 5. When determining the placement coordinates of logic symbols, it is important to note that the coordinate values in the vertical axis direction, which serve as a reference for arranging multiple sets of logic symbols that can be arranged horizontally in one line, are specified by the user. 4. A method for automatically determining logic diagram display coordinates according to claim 3.