Electrical CAD drawing standards

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Foreword Computer-aided design application engineering is a high-tech intensive large-scale system engineering. Its promotion and application should be guided by standardization. The rapid development of electrical science and technology, the complex design of new products and new processes, and the sharp increase in workload have prompted the preparation of electrical technical documents, especially in electrical drawings, to gradually replace manual design. In order to adapt to the needs and use standard type specifications according to the characteristics, so as to enable its healthy development, this standard is specially formulated. Electrical diagrams use graphic symbols and annotated boxes to represent connection lines. Electrical drawings may include the drawing of the following electrical schematics, functional schematics, wiring diagrams, wiring diagrams, location and installation diagrams. This standard is not yet available. It should be recognized that the content and function of the final document is the same whether it is manual drawing or drawing. The difference should be the process means of drawing and the degree of standardization of the schematic diagram. Therefore, the requirements of this standard for the expression of the schematic content and other aspects mainly refer to the currently effective electrical drawing and other related* * The drawing rules reflecting the characteristics of the standard are formulated based on the analysis and summary of relevant standards and experience. This standard is proposed by the National Technical Committee on Documentation and Graphical Symbols and is under the jurisdiction of the Mechanical Science Institute, the drafting unit of this standard. The main drafter of this standard is Li Shilin, Guo Ting, Gao Huimin, Li Ping, Ma Jian, Shen Bing, Zhang Ying, People's Republic of China. * * Standard electrical engineering drawing rules * * Scope of implementation approved by the Bureau of Quality and Technical Supervision. This standard specifies the general rules for electrical engineering drawing. This standard applies to electrical functional diagrams, including schematic diagrams, functional diagrams, circuit diagrams, wiring diagrams. Referenced standards. The provisions contained in the following standards constitute the text of this standard by reference in this standard. The versions shown in the standards are valid at the time of publication. All standards are subject to revision. Parties using this standard should explore the possibility of using the latest version of the following standards. Hydraulic and pneumatic graphic symbol information Seven-bit coded character set for information processing and information exchange Quantities and units Identification and application of electrical equipment wiring terminals and specific wire ends General principles of the alphanumeric system Mechanical drawing drawing method Mechanical drawing dimension annotation Graphical symbols for electrical schematics Project codes in electrical technology Graphical symbols for electrical equipment Preparation of electrical technology documents Part General requirements Preparation of electrical technology documents Part Functional schematics Preparation of electrical technology documents Part 1 Wiring diagrams and connections Wire table Color and numerical identification of wires Provisions for electric circuits and magnetic circuits Technical drawing title bar Codes for electrical color signs Technical drawing drawing format and format Technical drawing proportions Technical drawing fonts Technical product documentation Computer-aided design and drawing vocabulary Codes for signals and connecting wires Text symbols used in electrical technical documents Part General provisions Building diagram projection method Process detection control functions and instrument symbol drawing methods Part Process computer definitions This chapter gives the following definitions. For other terms and definitions, see and schematic diagram. A diagrammatic form that uses graphical symbols and annotated boxes to represent the relationship between multiple components or parts of a system or equipment, including wiring. A schematic diagram represents the main relationships and connections between items in a system, subsystem, device, component, equipment, software. A relatively simple diagram that usually uses a single line representation. Functional diagram uses a theoretical or ideal circuit without involving implementation methods to express the functions of a system, subsystem, device, component, equipment, software, etc. in detail. Simplified circuit diagram represents system subsystems, devices, components, equipment, software, etc. A simple diagram of an actual circuit uses graphical symbols arranged according to function to represent components and connection relationships to express functions without considering the actual size, shape or device of the project. Wiring diagram is a simple diagram that represents or lists the connection relationships of a device or equipment. It can be divided into unit wiring diagrams, interconnection wiring diagrams, terminal wiring diagrams and cable diagrams. Computer-aided design includes design activities such as drawing and narrative. In the information processing system, computers are used to complete a certain design task. The rules that should be followed when developing and applying drawing software. Electrical engineering drawings should comply with the general requirements for electrical drawing. See Chapter 1 for details. At the same time, they should comply with the following basic rules. Establish a corresponding database. In order to maintain consistency between all documents and between the entire device or equipment and its documents, a database of design data supporting electrical engineering drawing software should be established, including graphical symbols and files for electrical schematics. The database should To facilitate expansion, modification, calling and management, the symbols in the graphical symbol library used for electrical sketches should comply with the combination of symbols, derivation and design should comply with the requirements of this standard and related standards. Initial input system. When design data needs to be transferred between computer systems, in order to simplify the data transfer process, the initial input system should adopt recognized standard data formats and symbol sets. Guidelines for selecting and applying design input terminals. Design input terminals are an important way of drawing entry and documentation. In the selection and application The following guidelines should be observed when using these input terminals. The selected terminals should support applicable industry standards in terms of symbology and required formats. The input system should be designed to support standardized formats in terms of databases and related diagrams so that design data can be transferred between different systems or to other systems for further processing. Initial design input should be carried out according to the required documentation method. The data should be arranged in a way that allows for additions and modifications without involving extensive changes. General Rules for Drawing Documentation The final document must comply with the following consistency guidelines regardless of the method and media used to produce and store the document. These guidelines are consistent with relevant standards. Drawing formats. In formal documents prepared on drawings or corresponding media, their formats should be consistent with the tables and tables. Drawing edges and borders. Centering and positioning markings. Drawing frame zoning methods and title block identification areas. The location and size should conform to the title block. The content of the title block should conform to the drawing number. Each drawing should have at least one in the title. Corresponding drawing number A complete drawing composed of multiple drawings. Each drawing should have a related drawing number. The form, width and spacing of drawing lines should conform to the dot-dashed lines specified in the standard. Line types and specified boundary lines. Serial numbers. Lines consisting of any combination of short and long strokes. Equivalent fonts in electrical technical drawings and simplified diagrams. The fonts in electrical technical drawings and simplified diagrams should comply with the Chinese characters used. The arrows and guide lines should be long and imitate the Song Dynasty. A solid line and should point to the annotated place. The termination method of the leader line. The end can be terminated on the connection line with a short diagonal line connected to both the connection line and the leader line or with an arrow. See the figure. The end is terminated with a dot within the object outline. See figure. The end is terminated with an arrow on the object outline. See figure. There is no need to add a termination symbol on the dimension line. See figure. The end dimension line of the leader line. The labeling of the end point and the starting point dimension line should conform to the diameter of the starting point mark. The dimension should be the dimension. Times of the line width, left and right views, orthographic projection diagrams can use one of the two specified methods, but only one projection method is used in a diagram. The construction site map should be drawn in proportion. The scale selection should be consistent and the scale should be given in the diagram. The layout of the simplified diagram is a summary diagram of the signal flow direction. Functional diagram. The main flow direction of the signal flow in the circuit diagram should be from left to right or from top to bottom. When the direction of a single signal flow is unclear, an arrow symbol should be drawn on the connecting line. The layout of the symbols is functional. Symbols and circuits in the diagram should be laid out in working order. Function-related symbols should be grouped and arranged close to each other. In the diagram of the control system, the main control system functional group should be arranged to the left or above the controlled system functional group. The position and arrangement of the grouped symbols in the diagram should be able to express the actual location of the corresponding components. The graphical symbols in the diagram should conform to or be derived or combined according to the rules. If the required symbols have not been standardized, they should be in the diagram or support. Annotate the selection of symbols in the file. When certain devices have different types of standard symbols, such as transformers, inductors, autotransformers, induction voltage regulators, transformers, etc., the size of the symbol should be selected according to the actual purpose of the diagram. The meaning of the symbol depends on its shape and content. Its size and symbol line width generally do not affect the meaning. According to the symbol design rules, the module used is used to facilitate marking of terminals. The distance between connections is usually selected. In electrical drawings, all symbols are This parameter should be drawn in or stored in the symbol library. Under the following circumstances, symbols of different sizes can be designed in the simplified diagram. To increase the number of input or output lines, to facilitate supplementary information, to highlight certain aspects, and to use symbols as limiting symbols. The basic orientation of symbols with signal flow orientation should be designed from left to right. When the basic orientation of the symbol needs to be changed, it can be turned or mirrored without changing the meaning of the symbol. Gas drawing software should have the function of turning symbols or mirroring them. For most symbols, it is not necessary to draw the terminal symbol in the simplified diagram. In some cases, for example, if the terminal symbol is part of the symbol, the terminal symbol must be drawn or the terminal code should be marked. The representation of the lead lines. The positions and drawing methods of most lead lines in the symbols specified by the standards are only given as examples. In the simplified diagram, it is allowed to draw lead lines in other positions of the symbol without changing the meaning of the overall symbol. When the lead line position When the position affects the meaning of the symbol, the connection line should be drawn as follows. Except for the simplified diagram laid out by position, the connection line should be a straight line and should be oriented horizontally or vertically as much as possible. Bends and cross-connection points should be avoided as much as possible. In electrical drawings, contact symbols should be drawn at the joints of the connection lines. Dots should be drawn to represent important circuits. Certain important circuits that need to be highlighted or distinguished in the diagram should be represented by thick solid lines. Planned reserved connection lines can be represented by dotted lines. When connecting lines are marked, When marking is required, the mark should be placed on the top edge of the horizontal connection line and on the left side of the vertical connection line or at the interruption point of the connection line. The interruption line can be interrupted when the connection line needs to pass through most of the width or dense area. The two ends of the interruption line should be marked. One or more of the following signal codes or other text marks can be used. Symbols connected to the ground chassis or other common points are shown in Chapter 1. Position markings for insertion tables. See other methods for parallel connection lines. Parallel line grouping. When adjacent parallel lines reach Or when there are more than six, they should be arranged in groups. In the functional diagram and circuit diagram of the schematic diagram, other connecting lines should be grouped by function. Arrange the wire harness in a group by no more than 1 connecting wire. If the connection lines are the same but the order is not obvious, a dot should be marked at the end of the first parallel line. When the order of the parallel lines is different, a mark should be drawn at each end of each parallel line. If necessary, a symbol can be used to mark the number of connecting lines. Information bus. If the connecting line is to represent the transmission of several information buses, the bus can be marked by symbols and on the connecting line. Bus indicator symbols. In the simplified diagram, items that belong to the same unit in function or structure can use boundary line symbols and are regularly enclosed to form an enclosing frame. If there are items that do not belong to the unit within the enclosure of a unit, a set of enclosures surrounded by symbols of any combination of double long dashes or other long dashes can be used to enclose these items and add text comments. If part or all of the terminal board or connector is part of a functional or structural unit, its symbols should be enclosed within the enclosure. The simplified method of connecting the conductive chassis, chassis, or shielding to the conductive chassis, chassis, or shield should be clearly shown in the simplified diagram. Simplification is used in the diagram. The drawing method can increase the amount of information in the drawing. Terminals. Multiple terminals on a component can be represented by one terminal and the number of terminals should be marked on the terminal line. Terminal codes can be marked in the original order and separated by commas. Consecutive numbered codes can only be marked with the first and last terminal codes separated by ellipses. When two or more components are interconnected with multiple terminals, the terminal codes of all components should be arranged correspondingly from left to right. Symbols composed of the same symbols should be arranged in order from left to right. A symbol group composed of several identical symbols can be represented by one symbol, but a short slash should be added to the symbol and the number of symbols represented. For rectangular symbols, the number of symbols represented by the symbol and the multiplication sign can be marked in the box and square brackets can be added. For example, the repeated representation method The part of the connecting line in the device that is not shown can be omitted in the diagram. The symbol at this time does not represent a complete device. The function mark in the symbol can be supplemented. The connector or terminal board in the frame is used as a Connector or terminal board symbols that are components of a unit may be omitted. Circuits represented by enclosing boxes within a unit may be simplified if circuits represented by enclosing boxes within a unit are described in more detail. Item and terminal codes used in the simplified diagram should comply with the project code. An item code should be marked at each symbol representing an element or its component part. In devices and equipment, one item corresponds only to a unique item code. The location of the item and terminal code All should be marked next to it. When there is a connecting line, it should be marked above the horizontal line and to the left of the vertical line. When the above marking position is difficult to achieve, the project code can be marked in other locations, such as inside or outside the frame. The character set that forms the information code can only be limited to the code table specified in and does not include control characters. If the computer can only process eight-bit character sets, it is recommended to use the following characters. Uppercase letters, numbers, negative characters, upper dash logical negation, when seven-bit characters must be used, use tilde separator, lower dash or space. Item code separator colon arithmetic operator dash or minus sign plus sign Boolean operator upper dot special character signal code length is limited to 1 character. The quantity and sum in the alphabetic symbol mark diagram are The letter symbol of the unit should conform to or be omitted if the physical properties represented by the graphic symbol are very obvious. For example, the letter next to the resistor symbol can be simplified to a position mark. The most common method of indicating the position of the item in the diagram is the specified drawing frame partition method. Use row letters and column numbers or alphanumeric combination codes to determine the specific provisions of the drawing frame partition. The two sides of the drawing that are perpendicular to each other are equally divided into several even-numbered grids. The length of any divided side should be no less than and no longer than the marked The order of noting letters and numbers can start from the upper left corner. When using position marks, the drawing number, drawing number or project code can be placed before the position mark or the location partition code can be placed in brackets. Technical data of the component. The technical data of the component in the diagram can be marked inside or next to the component symbol, usually under the project code. The shape can be supplemented with text description. The following marking method can be used to mark the horizontal connection line or the left side of the vertical connection line along the direction of the connection line, but it must not contact or intersect with the connection line. Place the waveform in a closed symbol, preferably in a circle, and connect it to the connection line through a lead. Draw a short diagonal line at the connection and place it separately in other places. The corresponding signal waveform on the connection line can be expressed by marking text explanations. Information contained in binary logic components can be marked according to the general information. Note: Supplementary information that defines the symbol within the outline of the symbol can be marked within square brackets. Annotations and identification information can be annotated. Notes should be placed near the object to be explained or marked, such as a footnote number, and then marked near the edge of the drawing border line. The general general annotation for multiple documents should be on the first page. If there is an information mark for the human control function on the equipment control panel, the information mark should also be marked on the simplified diagram. Expressions written in a single line near the relevant graphic symbols. The following methods are recommended for negative representation. One of them is to use a logical negation symbol before the expression. If the computer does not have this symbol, a tilde character can be used. Add a functional diagram after the expression. General rules. Functional diagrams include schematic diagrams, functional diagrams and circuit diagrams. They should comply with the requirements of Chapters and Chapters. At the same time, they should comply with the requirements of Chapter Chapter. The layout of graphic symbols and circuits should be in accordance with the requirements of Chapter Chapter. The main circuit should be laid out from left to right or from top to bottom in terms of emphasizing the process and signal flow. To emphasize the functional relationship, graphic symbols of functionally related items should be arranged close to each other and the following requirements should be considered. To emphasize the signal flow, the connecting lines should be kept as straight as possible. Commonly used basic circuits should adopt standard patterns. Equally important or functionally related parallel branches should be arranged symmetrically. Parallel similar items in vertical and horizontal branch circuits should be arranged horizontally and vertically in alignment. When there is a conflict between emphasizing signal flow and emphasizing functional relationships, for within a functional group and for larger scales, In small or less complex equipment, priority should be given to signal flow. For a system and complex equipment, the overall functional structure should be emphasized and priority should be given to functional grouping. Positional notation. To facilitate finding the graphical symbols or interrupt line locations in the diagram, the following positional notation can be used. Picture frame partitioning method is shown in the circuit numbering method. Each branch of the circuit is identified by numbers. The table method is to repeatedly mark the project code in the peripheral list of the simple diagram and align it with the corresponding graphic symbol. Graphical symbol of the project. It can be used to represent a specific project, such as a specific component. It can also be used to represent functions. The selection of graphical symbols should conform to the component representation method. For simpler circuits, the given centralized representation and combined representation can be used. When the circuit is more complex, the following representation can be used. Semi-concentrated representation. The symbols of the functionally related parts of the component are expanded and arranged in the simplified diagram. The connection symbols represented by dotted lines are used to connect the symbols of the functionally related parts for clarity. Clearly represent the circuit layout. This method is usually used to represent components with mechanical functional connections. Separate representation. Symbols for functionally related parts of the component are scattered on the diagram. Each part is represented by the same item code of the component as the same component. If necessary, the location from the excitation part, the driving part, to other parts can be shown. The retrieved information can be made into an illustration or an insert table and placed near the excitation part, the driving part or separately in other places and marked with the destination. Repeat. Representation: Each component with independent functions in the component is shown in centralized representation in several places, but only partially connected at each place. The same terminal that appears multiple times in the diagram should be marked with a terminal code, but the connection only needs to be shown in one place. Repeated terminal codes can be bracketed or use special identifiers. Separate representation. If there is no functional connection or relationship between the components with independent functions in the component, the symbols of these components can be shown separately on the diagram to represent the component composition. Each symbol of the part should be marked with the item code indicating that it is the same component. Several representations can be used in combination. Functionally independent components in the component. Combined representation and discrete representation. One of the separate representations and repeated representations can be combined with the centralized representation according to the specific conditions of the component. Semi-centralized representation. One of the separate representations and repeated representations. The component representation can be used in combination. The drawing of the working position or state. Manual or electromechanical components in a single stable state should be drawn in the non-energized or power-off state. For example, Relays, contactors, brakes, clutches, circuit breakers and isolating switches are drawn in the off position. For other switching appliances with two or more stable states, they can be drawn in any position. Manual control switches with multiple stable positions marked off are drawn in the off position and drawn in other prescribed positions. Function description. For manual control switches with complex functions, tables, diagrams, symbols, tables, codes, comments, etc. can be used to explain their action functions. The method of using contact symbols to represent semiconductor switches can be used. The contact symbol indicates the contact position of the semiconductor switch without contact. The orientation of the contact symbol is drawn according to the moment when the auxiliary power is turned on, that is, the initial state. In order to be consistent with the set action direction, the orientation of the contact symbol should be when the element is excited. The contact action of the horizontal connection line is upward. The contact action of the vertical connection line is to the right. Functions realized with the help of software. If it is necessary to indicate that the function is realized with the help of software, the hexagonal symbol in should be used as the limiting symbol. In the simplified diagram of the power circuit, The power supply connection of the components can be represented by power connection lines, table comments, etc. The power lines can be concentrated on one side of the diagram, the upper and lower power lines can also be interrupted. The power lines on the box symbols are usually drawn at right angles to the signal flow. The representation of electrical and non-electrical combination circuits should be clearly expressed in the simplified diagram. The representation of binary logic circuits. When using binary logic component symbols to represent hardware, it is necessary to determine whether to use one of the following two methods to represent the logic state. and the relationship between the logical level of the physical quantity value that represents the state. This method requires the use of a single logical convention for all or part of the diagram. Positive logic convention or negative logic convention adopts logical polarity representation. Single logic convention. The positive logic convention is for each logical connection. The more positive value level of the physical quantity corresponds to the external logic state. The less positive value level corresponds to the external logic state and is marked in the diagram with the following symbols. Negative logic convention is for each logic. Logical connection of physical quantities The less positive value level corresponds to the external logic state. The more positive value level corresponds to the external logic state and is marked in the figure with the following symbols. Logical polarity representation. The relationship between the internal logic state and the external logic level of each input or output terminal of each binary logic element should be directly expressed by the presence or absence of the logic polarity indicator. Specifically, there is a logic polarity indicator at the input or output terminal to indicate the external low level and the internal state of the terminal. The corresponding non-logic polarity indicator indicates that the external high level of the terminal corresponds to the internal state. The relationship between the external logic level and the true or false signal state is only specified by the signal code. See the application of two types of graphical symbols. When a single logic convention is used in the diagram, the logic polarity indicator shall not be used. The number of logical NOT symbols should be minimized in the function diagram of a single logic convention to facilitate understanding of the function of the diagram. In the circuit diagram, the input terminal of the logic element and the input terminal fed to the input terminal Logical polarity symbols or logical NOT symbols on the signal source should be as identical as possible. Logical symbol mismatch may occur in the logic circuit. To highlight this mismatch, a mismatch symbol should be added to the connecting line plus a short vertical line. Current direction, magnetic flux direction, voltage polarity, current reference direction in the branch, magnetic flux direction, voltage reference polarity mark, and the corresponding relationship between the voltage polarity of the coupling circuit should conform to the pattern of commonly used basic circuits. Commonly used basic circuits should adopt standard fixed patterns, including passive Two-terminal four-terminal network common base common emitter common collector coupled amplifier basic bistable circuit basic bridge circuit circuit mode details see the simplified method of the simplified circuit of the same branch Two or more identical branches can be simplified by one branch and the branch symbol or the provisions of the simplified functional unit functional group or structural unit functional unit functional group or structural unit can be represented by a terminal function diagram or a box symbol. At this time, it should be given in the terminal function diagram or box symbol Retrieve mark for detailed information. Simplification of repeated circuits. Circuits with repeated arrangements can be drawn in detail only once. Other circuits should use appropriate simplified representation methods. At this time, the comparison relationship between the components in the simplified circuit and the components in the detailed circuit should be shown in detail. Supplementary information. In order to facilitate the understanding and application of the circuit, supplementary information such as external circuits and text descriptions can be added to the diagram. The overview diagram should show the overview of the system, subsystem, complete set of equipment, software, etc. and show The outline diagram can be used as a basis for preparing more detailed diagrams such as functional diagrams, circuit diagrams, etc. The layout diagram should be drawn according to the functional layout method. When the location information is important for understanding the function, such as a network diagram, the position layout method can be used. The diagram can be drawn at different levels of function or structure. A higher level description of the overall system and a lower level description of the subsystems in the system. A summary diagram of a certain level should be A schematic diagram containing labels for retrieval and description of lower-level documents used to represent the project. The layout of graphical symbols including box symbols used to represent the project should be such that the flow of information control energy and materials is clear and easy to distinguish and identify. When necessary, each graphical symbol should be marked with a project code. A schematic diagram of a non-electrical process control system. A schematic diagram of a non-electrical process control system should be drawn based on the flow chart of its process. Functional diagrams should represent the functional characteristics of system subsystems, complete sets of equipment, software, etc. Detailed but not considering how the function is implemented, the function diagram should at least include the necessary functions, graphic symbols, function signals, main control connection lines, etc. It can also include information such as waveforms, formulas, algorithms, etc., but generally does not include physical information such as locations, physical items, terminal codes, and assembly information. Circuit diagram purpose and content. The circuit diagram should represent the details of the actual circuit such as the system, subsystem, complete set of equipment, etc., but does not need to consider the physical size, shape, or location of its component items. The purpose is to understand the circuit. The role of providing certain information, providing necessary information for preparing wiring files, providing necessary information for testing and troubleshooting, providing information for installation and maintenance, what the circuit should contain, graphic symbols representing components or functional parts in the circuit, connection lines between components or functional parts, project codes, terminal codes, level conventions for logic signals, information necessary for circuit tracing, signal code names, position retrieval marks, necessary supplementary information for understanding functional components, graphic symbols for multi-terminal components, Components with many terminals, such as hundreds, can be represented by the following method if their graphical symbols occupy too large a space on a single diagram and it is inconvenient to read the diagram. If the component has several functionally independent parts, it can be represented by discrete representation. If the component has several functionally related parts, it can be represented by semi-centralized representation. If possible, internal function diagrams and internal connecting lines can be used to replace the symbol of the component. A simplified method is used, that is, a single terminal symbol is used to represent the related multiple components. Simplify the details of each terminal and illustrate them in separate diagrams or tables. If there is no alternative, the symbol box can be divided into several parts to draw the representation method of the main circuit. The representation method of the main circuit in the circuit diagram of the power plant control system should be based on the principle of facilitating the study of the function of the main control system. Usually, a single-line representation is used for the main circuit or part of it. When necessary, a multi-line representation can also be used. For example, the unused parts of the connecting elements of the transformer are functionally related but not used. The parts should be shown or noted in the circuit. Distributed connection line and line or distributed connection means that some logic units can complete the connection of AND or OR functions only by connecting without additional logic units. The AND or functions realized by distributed connections are respectively called line and line or distributed connection. Line and line or can use the following two notation methods. Use the connection point symbol plus the logical function AND or limit symbol to represent it. Since the method does not have a box symbol, it is impossible to use input and output limits. The symbolic method uses a box symbol instead of a connection point and adds a line and or line or qualifying symbol or representation in the box. The input and output terminals of the box symbol can be used in the method. Logical NOT symbols and polarity indicator symbols are used. The diagram shows the two distribution connection representations and the graphic symbol method. The method and or diagram graphic symbols for the two distribution connection representations. General rules for wiring diagrams and wiring tables. It is generally stated that the wiring document should contain information identifying the connection point of each connection and the conductor or cable used. For terminal wiring diagrams and terminal wiring tables, it is only necessary to show one end. The following information may be included when necessary. Types of wires or cables, including model number, material structure specifications, insulation color, voltage rating, number of wires, other wires, cable numbers or project codes, marking or representation methods of connection points, such as project codes and or terminal codes, graphical representation, remote marking, laying direction, end processing, bundling, stranding, shielding, etc. Description or method of wire or cable length, signal code, and/or signal technical data need to be supplemented. For other information that is fully explained, for the color or number identification method of the conductor, see the code regulations for electrical color signs. For the regulations on project codes, see wiring documents. The information provided should be based on the principle of clear expression and can be in the form of a simplified diagram or table or a combination of both. The preparation of wiring documents should comply with the requirements of Chapter 1 and this Chapter. Wiring diagram layout. Wiring diagrams should adopt the positional layout method but do not need to be proportional. The components and terminals should be represented by a simple outline, such as a square, rectangle, circle or simplified graphic. Representation can also be represented by prescribed graphic symbols. Terminals should be clearly shown but there is no need to show terminal symbols. Representation method of wires. The actual wires between terminals can be continuous solid lines. Single line or multi-line representation can be used to represent the wires. Interrupted wires can be distinguished by project codes. Appropriate methods can be used to associate interrupted lines. When a large amount of wire connection information needs to be expressed in a small format, a matrix layout form can be used. The rules for connecting terminals are as follows: network form Each terminal should be arranged and marked. All terminal symbols on each component should be arranged in vertical and horizontal directions, but there is no need to arrange them in the actual order of component terminals. Terminals that need to be connected between components should be aligned in horizontal and vertical directions. Wires should be connected in horizontal and vertical directions and pass through the connected terminal symbols. For wires with named signals flowing through them, the signal code should be indicated at one end of the connecting line. When wires between two points need to be marked, they should be marked above and left of this horizontal and vertical connecting line. Note Wire number wiring table layout The wiring table can be compiled in one of the following two formats. The terminal-based format lists the components and their terminals that need to be connected in sequence in the table, and the connecting wires connected to the terminals include the project code wires or cable core wire numbers. The connecting wire-based format lists the connecting wire numbers in the table in sequence and lists all the terminals or terminal codes connected to the connecting wires. Components and terminals should be expressed using project codes. Use the terminal code marked on the terminal. When there is no code marked on the terminal, you can set the terminal code yourself and explain it in the wiring table or related documents. The same terminal should only correspond to the unique terminal code in all related documents. For using graphic symbols or colors as a form of identifying terminal codes, the prescribed text code or prescribed color code can be used instead of the wire representation method in the wiring table. The actual project code can be represented by one or more of the following methods. Marking or color of connecting wires. Identification numbers set at will. Terminal group to which the connecting wires are connected. Unit wiring diagram and unit wiring table. A unit wiring diagram and unit wiring table should provide all the information required for internal connections of a structural unit or unit group. Information on external connections between units does not need to be included, but a search mark for the corresponding interconnection diagram or interconnection table can be provided. A selected view of the component layout view within the structural unit should be able to most clearly represent the terminals of each component. Position and connection When one view is not enough to represent multi-faceted connection and wiring information, multiple views can be used to represent the arrangement of component terminals. The relative arrangement position of the terminals should be consistent with their actual positions. The terminals do not need to show the view when the components overlap. When the components are stacked into several layers, the method of flipping away or rotating can be used to represent these components in the same view. The interconnection diagram and interconnection table should provide information between different structural units of the equipment or device. Information required for connections does not need to include information on internal connections within the unit, but appropriate retrieval markings may be provided. Components and connecting wires shall be drawn in the same plane. Terminal wiring diagrams and terminal wiring tables shall provide information required for external connections of a structural unit or a device. Drawing rules shall be consistent with interconnection wiring diagrams and interconnection wiring tables. Terminal wiring tables may be in grid form. Connection point information shall be arranged in a grid in the table. Terminal codes for each structural unit shall be arranged horizontally. The cable codes connected to the terminals are arranged in order in the direction. The number of core wires and the specific connection relationship and the remote mark of the connecting wire are listed vertically in sequence. The code of each core wire is listed vertically with the terminal number it is connected to. The spare core wires are marked in the last column of the same row. Cable diagrams and cable tables. Cable diagrams and cable tables should provide all the information required for laying cables between structural units of equipment or devices. Information on cable paths should be included when necessary. Single cable groups can be represented by the single line method and the cable item code should be added.