This standard specifies the requirements for graphic symbols described in a computer electronic file format in a reference symbol library and the requirements for their exchange between computer-aided tools. The reference symbol library can be used as a basis for the preparation of technical documents, and the exchange of documents and graphic symbol libraries between computer-aided tools. GB/T 16901.2-2000 Rules for the representation of graphic symbols Graphic symbols for product technical documents Part 2: Specification for computer electronic file format of graphic symbols (including graphic symbols in the reference symbol library) and requirements for their exchange GB/T16901.2-2000 Standard download decompression password: www.bzxz.net
This standard specifies the requirements for graphic symbols described in a computer electronic file format in a reference symbol library and the requirements for their exchange between computer-aided tools. The reference symbol library can be used as a basis for the preparation of technical documents, and the exchange of documents and graphic symbol libraries between computer-aided tools.

GB/T16901.2—2000
This standard is equivalent to IEC81714-2:1998 "Design of Graphical Symbols for Product Technical Documents - Part 2: Specification for Computer Electronic File Format of Graphical Symbols (including graphic symbols in the reference symbol library) and their exchange requirements". The content of the standard is basically the same, with only minor changes in the format. When adopting the standard, the content of 6.18 was adjusted accordingly according to my country's national conditions. At the same time, the content of 6.18 in IEC81714-2 was fully attached to this standard as Appendix N (suggested Appendix) for reference. This standard is the second part of the second standard in the series of "Rules for the Representation of Graphical Symbols". The structure and name of this series of standards are as follows: GB/T16900-1997 Graphical symbol representation rules General principles GB/T16901.1-1997 Graphical symbol representation rules Graphical symbols for product technical documents Part 1: Basic rules GB/T16901.2-2000 Graphical symbol representation rules Graphical symbols for product technical documents Part 2: Computer electronic file format specifications for graphic symbols (including graphic symbols in the reference symbol library) and exchange requirements GB/T16901.3 Graphical symbol representation rules Graphical symbols for product technical documents Part 3: Classification and coding of connection points and connection networks
GB/T16902.1-1997 Graphical symbol representation rules Graphical symbols for equipment Part 1: Formation of graphic symbols GB/T16902.2 Rules for the representation of graphic symbols Graphical symbols for equipment Part 2: Use of arrows GB/T16902.3 Rules for the representation of graphic symbols Graphical symbols for equipment Part 3: Formation of graphic symbols (icons) on screens and displays
GB/T16902.4 Rules for the representation of graphic symbols Graphical symbols for equipment Part 4: Guidelines for the application of graphic symbols GB/T16903.1-1997 Rules for the representation of graphic symbols Graphical symbols for signs Part 1: Formation of graphic signs GB/T16903.2 Rules for the representation of graphic symbols Graphical symbols for signs Part 2: Visual design principles for graphic symbols GB/T16903.3 Rules for the representation of graphic symbols Graphical symbols for signs Part 3 Division: Procedure for the development and testing of graphic symbols GB/T16903.4 Rules for the representation of graphic symbols Graphic symbols for signs Part 4: Principles and requirements for the use of graphic symbols Note: Among the above standards, GB/T16901.3, GB/T16902.2, GB/T16902.3, GB/T16902.4, GB/T16903.2, GB/T16903.3 and GB/T16903.4 are national standards to be formulated. Some of the above standards have corresponding national standards and will be included in this series of standards when they are revised. They are: GB1252-1989 Graphic symbols arrows and their application (revised to GB/T16902.2) GB/T14543-1993 Graphic symbols for signs Visual design principles for signs (revised to GB/T16903.2) GB12103-1990 Development and testing procedures for graphic symbols for signs (revised to GB/T16903.3) GB/T15566-1995 Principles and requirements for the use of graphic symbols (revised to GB/T16903.4) This standard is the second part of the GB/T16901 series and can be used as the basis for the design of graphic symbols for computer-aided tool (CAx) systems in all technical document fields. This standard can be applied to future versions such as GB/T4728 and ISO14617 and future networks based on the databases of these two standards. Regarding other subject areas, the subsequent parts of the standard are being considered. Appendix E, Appendix F, Appendix G, Appendix J and Appendix K in this standard are standard appendices, and Appendix A, Appendix B, Appendix C, Appendix D, Appendix H, Appendix L, Appendix M and Appendix N are suggested appendices. Appendix A describes the relationship between this standard and future versions of ISO 14617 and ISO 14617 [12]. Appendix B contains information on the exchange of graphic symbol libraries between computer-aided systems. Appendix C contains the EXPRESS-GL 3,18 model of the requirements specified in this standard. 1) The numbers in square brackets refer to the numbers of the items listed in the references in Annex L. The same applies below. 1
GB/T 16901.2—2000
Annex D contains an EXPRESS-G model of how to identify products worldwide and how to associate the identified products with specific functional expressions of the products through graphical symbols. Annex E lists the data types, recommended lengths and default values ​​of the attributes used in the EXPRESS-G model in Annex D. Annex F contains drawing requirements that are not actually included in the current version of ISO 128. Annex G contains text requirements that are not actually included in the current versions of ISO 14691 and ISO 3098-5. Annex H lists predefined hatching patterns that may be used in drawings and graphic symbols. Appendix J contains a description of the application of this standard to create different versions of the base symbol library. Appendix K contains the requirements for the global definition of graphic symbols in the base symbol library. Appendix L lists the references related to this standard. Appendix M lists examples of data element types used in GB/T4728. Appendix N contains the names of the base symbols specified in IEC81714-2. This standard shall be implemented from March 1, 2001. This standard is proposed and coordinated by the National Technical Committee for Standardization of Graphic Symbols and the National Technical Committee for Standardization of Electrical Documents and Graphic Symbols.
This standard was drafted by the China Standards Research Center, the Institute of Mechanical Science, and Tsinghua University. The main drafters of this standard are: Chen Yuanqiao, Bai Dianyi, Guo Ting, Zhang Liang, Xu Longwen, Qiang Yi, and Zhan Junfeng. 2
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IEC Foreword
1) EC (International Electrotechnical Commission) is a worldwide organization for standardization composed of all national electrotechnical committees (IEC National Committees). The goal of IEC is to promote international cooperation on all standardization issues in the electrical and electronic fields. For this purpose, EC publishes, among other activities, international standards. The preparation of international standards is entrusted to technical committees. Any national committee of EC, if interested in the subject matter of the standard, can participate in the preparation of the standard. International organizations, governmental organizations and non-governmental organizations that maintain liaison with EC can also participate in the preparation of standards. IEC and ISO (International Organization for Standardization) work closely together in accordance with the agreement reached by the two organizations. 2) Since each technical committee represents all interested national committees, the formal resolutions or agreements of IEC on technical issues can be as close as possible to the international consensus on the relevant issues. 3) The documents published and published are in the form of recommendations for international use: standards, technical reports or guidelines. These are accepted by national committees.
4) In order to promote international unification, IEC national committees commit to adopt IEC international standards to the maximum extent possible in their national and regional standards. Any differences between IEC International Standards and the corresponding national or regional standards shall be clearly stated in the latter. 5) IEC does not provide a marking procedure to indicate its approval, nor does it accept responsibility for any equipment claiming to conform to one of its standards. 6) Attention is drawn to the possibility that some of the contents of this International Standard may involve patent rights. EC is not responsible for identifying any or all such patent rights.
International Standard IEC 81714-2 was prepared by IEC Technical Committee 3 (Documentation and Graphical Symbols), Subcommittee 3B (Documentation). The text of this standard is based on the following IEC documents: FDIS
3B/220/FDIS
Voting Report
3B/240/RVD
For details of the voting report on this part of this standard, see the voting report documents listed in the table above. In order to include all requirements for graphical symbols in a single numerical series, ISO Technical Committee 145 (Graphical symbols) and IEC Technical Committee 3 together with ISO Technical Committee 10 (Technical drawings, product definitions and related documentation) agreed to publish all parts of this International Standard in the 81714 series. The ISO Technical Management Board (ISO/TMB) and the IEC Executive Committee (IEC/CA) decided to select one body to be responsible for the respective parts of this series of standards. The technical committees involved agreed that no part of International Standard 81714 would be changed without mutual agreement. International Standard 81714, under the general title "Design of graphical symbols for use on technical product documentation", consists of the following parts: Part 1: 1996, Basic rules (actually published by ISO as ISO/IEC 11714-1) NOTE: ISO Technical Management Board (ISO/TMB) decided to change ISO/IEC 11714-1 to ISO 81714-1 in accordance with the agreement on the common numbering system between ISO and EC.
Part 2: 1998, Specification for the format of computer electronic files for graphical symbols (including those in the reference symbol library) and their exchange requirements (IEC publication)
Part 3: 1998, Classification and coding of connection points and connection networks (IEC publication) For other subject areas, subsequent parts of the standard are under consideration. Part 2 can be used as the basis for the design of graphical symbols for CAx systems in all areas of product technical documentation. This standard can be applied to future versions of IEC 60617 and ISO 14617 and to future networks based on the databases of these two standards. Annexes E, F, G, J and K are part of the integral content of this standard. Annexes A, B, C, D, H, L and M are for reference only. 3
GB/T 16901.2—2000
Annex A describes the relationship between this standard and future versions of IEC 60617 and ISO 14617 [12]. Appendix B contains information on the exchange of graphic symbol libraries between computer-aided systems. Appendix C contains the EXPRESS-GL2,18 model of the requirements specified in this standard. Appendix D contains an EXPRESS-G model of how to identify products worldwide and how to associate the identified products with the specific functional expressions of the products through graphic symbols. Appendix E lists the data types, recommended lengths and default values ​​of the attributes used in the EXPRESS-G model in Appendix D. Appendix F contains drawing requirements that are not actually included in the current version of ISO128. Appendix G contains text requirements that are not actually included in the current versions of ISO3098-0 and ISO3098-5. Appendix H lists predefined surface line patterns that may be used in drawings and graphic symbols. Appendix J contains a description of the application of this standard to produce different versions of the base symbol library. Appendix K contains requirements for the global definition of graphic symbols in the base symbol library. Appendix L lists the references related to this standard. Appendix M lists examples of data element types used in IEC60617. 1 Scope
National Standard of the People's Republic of China
Rules for the presentation of graphical symbols
Graphical symbols for use in the technical documentation of products
Part 2: Specification for computer electronic file format of graphical symbols (including graphical symbols in reference
symbol library), and requirements for their interchangeGB/T16901.2—2000
eqvIEC81714-2:1998
This standard specifies the requirements for graphical symbols described in a computer electronic file format in a reference symbol library and the requirements for their interchange between computer-aided tools. The reference symbol library can be used as the basis for the preparation of technical documentation and the exchange of files and graphical symbol libraries between computer-aided tools. This standard does not contain the physical file format specifications required for the interchange. 2 Reference Standards
The provisions contained in the following standards constitute the provisions of this standard through reference in this standard. When this standard is published, the versions shown are valid. All standards will be revised, and parties using this standard should explore the possibility of using the latest versions of the following standards. GB/T1988-1998 Information technology - Seven-bit coded character set for information exchange (eqvISO/IEC646:1991) GB/T2659-2000 Codes for names of countries and regions of the world (eqvISO3166-1:1997) GB/T4728 (all parts) Graphic symbols for electrical schematics (eqvIEC60617) GB/T4880-1991 Codes for language names (eqvISO639:1988) GB/T6988.1-1997 Preparation of electrical technical documents - Part 1: General requirements (idtIEC61082-1:1991) GB/T10609.4-1989 Requirements for microfilm originals for technical drawings (neqISO6428:1982) GB/T14691-1993 Fonts for technical drawings (eqvI ISO3098-1:1974) GB/T15565-1995 Graphical symbol terminology
GB/T16901.1-1997 Graphical symbol representation rules Graphical symbols for product technical documents Part 1: Basic rules
(eqvISO/IEC11714-1:1996)
GB/T17151.1-1997 Computer graphics information processing system programmers hierarchical interactive graphics system Part 1: Functional description (eqvISO/IEC9592-1:1989)
3 Technical drawing lines (idtISO128-20:1996) GB/T174501998
State Administration of Quality and Technical Supervision 2000-06-07 Approved 2001-03-01 Implementation
GB/T16901.2——2000
ISO128-21:1996 Basic principles of representation in technical drawings Part 21: Preparation of drawings for CAD systems ISO3098-5:1997 Fonts for product technical documentation Part 5: Letters, numbers and symbols in the Latin alphabet for use with CAD 5 Information technology Coded graphic character set for preparation of electrical technical documentation and information exchange IEC61286.1995
IEC61346-1:1996
Principles of composition and reference markings for industrial systems, components and equipment, industrial products Part 1: Basic rules
Design of graphic symbols for product technical documentation Part 3: Classification of connection points and connection networks and their IEC81714-3.1998
Note: EC81714-3 is intended to be adopted as the national standard GB/T16901.3 of my country. ISO/IEC6429:1992 Control functions for information processing coded character sets Note: GB/T5261-1994 "Control functions for information processing seven-bit and eight-bit coded character sets" is equivalent to ISO6429:1988, ISO6429:1988 has been revised to ISO/C6429:1992.
ISO/IEC6523:1998 Information technology - Identification structure of organizations and their subordinate departments 3 Definitions
In addition to the definitions in GB/T15565, GB/T16901.1 and IEC61346-1, this standard also adopts the following definitions. 3.1 Graphic symbols for files
3.1.1 Function symbol functionsymbol
A graphic symbol that represents an object with clear performance and has input and output function nodes. Note: An example of a function symbol is the symbol that represents the "AND function". 3.1.2 Product symbol productsymbol
A graphical symbol that represents an object with well-defined properties and has nodes, especially implemented in hardware or software. 3.1.3 Graphical symbol instance graphicalsymboloccurrence A graphical symbol that is presented in a diagram and contains a data representation associated with the represented object. 3.1.4 Reference symbol referencesymbol A graphical symbol that has a clear identification of the data representation space associated with the object represented by the graphical symbol instance in the diagram. Note: Figures 11 and 12 give examples of graphical symbols with spaces. 3.2 Node
3.2.1 Connection point connectnode
Port port
Terminal terminal
Entry and exit points for object connection.
Note: Connection means:
1) A physical interface that provides a signal, energy or flow path between conductors and (or) contacts, or pipes and (or) piping systems. 2) A functional connection established between logical monomers, software modules, etc. for transmitting information. 3.2.2 (Schematic) Connection point (schematic) connectnode A location for connecting graphic symbols.
1 (Schematic) A connection point represents the terminal of the object of interest. 2 (Schematic) A connection point may not have a graphic shape, but is just a fictitious point associated with a graphic symbol. 3.2.3 Node name nodename
Identification of the connection point.
Ma codedconnectnodeclass
3.2.4 Connection point classification code
Classification code of the connection point.
3.2.5 (Schematic) Electrical node
(schematic) electricalnode
A connection point for connecting electrical network expressions. GB/T16901.2——2000
3.2.6 (Schematic) Function node (schematic) functionnode A connection point for connecting functional network expressions. 3.2.7 (schematic) linkage node A connection point for connecting mechanical linkage network expressions. Note: Figure 1 is an example of a connection point and a network. a) Mechanical linkage of relay elements
b) Mechanical linkage of relay elements using semi-split representation Figure 1 Example of connection point linkage representation
(schematic) matter node
3.2.8 (schematic) matter node
A connection point for connecting material transmission network expressions. Note: Matter refers to gas, liquid or solid. 3.2.9 (schematic) optical node (schematic) optical node A connection point for connecting optical fiber network expressions. 3.2.10 (schematic) wave node (schematic) wave node A connection point for connecting wave propagation network expressions. Note: Examples of wave propagation networks are infrared (radiation) and radio emissions. 3.3 Use of spaces
3.3.1 Space opening
A possible definition for writing information associated with the object represented by the graphical symbol instance. 3.3.2Descriptive block: A space for expressing descriptive information.
3.3.3Identifying block
A space for expressing a search code.
3.3.4Connection block
A space for expressing data associated with a connection point. 3.3.5Text text
c) A collection of letters, numbers and (or) other characters that convey information that can be understood by the reader through the mechanical connection between the motor and the generator. (GB/T16656.201)3.4Product identification
3.4.1Country codecountrycode
Country name code.
Note: GB/T2659 determines the list of country codes. 3.4.2Organization codeorganizationcodeSpecific organization name code.
Note: ISO/IEC6523 provides a method for how national authorized agencies assign organization codes. 3.4.3Organization nameorganizationnameSpecific organization identification. (GB/T16656.201)3.4.4Addressaddress
GB/T16901.2——2000www.bzxz.net
Detailed description of the postal delivery address or geographical location of an organization. (GB/T16656.201)3.4.5Product identification numberproductidentifyingnumberProprietary code that uniquely identifies a product within an organization. 3.4.6Universal product codeuniversalproductcodeinternationalarticlenumberEAN numberEAN number
A clear product identifier worldwide. ([20])3.5Graphical construction
3.5.1Graphical primitivesElements used for drawing in computer-aided drafting systems, such as straight lines, arcs, polylines, ellipsis symbols, etc. 3.5.2Scaling factorscalingfactor
The factor by which the coordinates of all determined points on a symbol are enlarged or reduced relative to the size of the symbol's reference point. 3.6 Arrangement of graphic symbols in schematic diagrams
3.6.1 Embedding areaembeddedarea
The area containing graphic symbols.
3.6.2 Connecting line directionsconnectinglinedirectionsThe direction of drawing connecting lines connected to schematic connecting points. 3.7 Graphic symbol management
3.7.1 Layerlayer
An independent data group that can be operated or displayed separately. 3.7.2 Symbol classificationsymbolclassificationThe classification of objects represented by graphic symbols.
3.7.3 Symbol classification codesymbolclassificationcodeThe classification code of objects represented by graphic symbols. 3.7.4 Symbol descriptionsymboldescriptionThe text description of the meaning of the graphic symbol.
3.7.5 Symbol namesymbolname
The identifier of a graphic symbol in the reference symbol library. 3.7.6 Symbol type symboltype
Classification attribute of graphic symbols (such as used to simplify symbol management in CAE systems), which allows specific values ​​to be assigned (for example: terminal, device, separate representation, concentrated representation, etc.). 3.7.7 Variant name variantname
Name identification of symbol variant.
3.8 Text
3.8.1 Character body characterbody
A rectangle that defines the horizontal and vertical boundaries of a single character. Note: All character boxes of the same lead font have the same height (see ISO/C7942-1). 3.8.2 Character aspect ratio characteraspectratio (GB/T16656.201) Character expansion factor characterexpansionfactor (GB/T17151.1) The ratio of the width to the height of the character box.
3.8.3 Character alignment characterjustification The alignment of characters within their character boxes. (GB/T17151.1) 3.8.4 Character spacing factor characterspacingfactor4
GB/T16901.2—2000
The spacing between adjacent character boxes. (GB/T17151.1) 3.8.5 Tabularlettering A character font in which the character boxes of all characters have uniform width. Note: The width of the character box is determined by its aspect ratio (width/height, b/h). 3.8.6 Proportionallettering Character font in which the character box of each character has its own width. Note: The width of the character box is determined by the character outline. 3.8.7 Line distance factor Line distance factor A factor that determines the distance between the baselines of adjacent text relative to the font height of the character. 4 Marking
4.1 Marking of reference points and connecting points
The following markings are used for the compilation of this standard:
Reference point
Reference point and connecting point
Anti-connection point
When it is necessary to indicate the (schematic) type of connecting point, this standard uses the letter code for the type of connecting point specified in IEC81714-3 instead of the asterisk (*) in the above markings.
4.2 Text alignment markings
In this standard, the following markings are used for the alignment and reading direction of connecting blocks, description blocks, logo blocks and text areas. 4T
Figure 2 Text alignment coding
According to the provisions of ISO3098-5, each alignment shall be coded as shown in Figure 2, see Appendix G (Standard Appendix). 5 Reference symbols
In order to compile stable and high-quality product technical documents in the shortest time at a low cost, the following aspects should be noted: a) The schematic diagram contains many graphic symbols, each of which involves the expression of other information of the represented object. In order to make this information readable, attention should be paid to the different flows of information and (or) energy in the schematic diagram and a comprehensive understanding of the schematic diagram when making graphic symbols. In order to reduce the workload of schematic drawing, graphic symbols can be stored in the reference symbol library. b) In order to minimize the amount of schematic data, in a schematic diagram, only one instance of a graphic symbol definition in a reference symbol library should be used, so that the system does not need to incorporate a graphic symbol as an embedded object in the schematic diagram, but only needs to simply reference the corresponding symbol definition in the relevant reference symbol library.
c) Due to the uncertainty of the application environment of the graphic symbol definition in the reference symbol library, when using graphic symbols in a schematic diagram, it is necessary to assign specific values ​​to the relevant data variables of the object represented by the graphic symbol so that the graphic symbol is specifically associated with the schematic diagram. At this time, the default value set in the graphic symbol definition in the reference symbol library is usually replaced by the relevant data of the graphic symbol instance in the schematic diagram. Only by making graphic symbols in a coordinated and consistent manner can the increasingly enhanced cross-domain interoperability, multi-vendor environment and data sharing needs in the drawing of schematic diagrams and the use of graphic symbols be met (see the appendix suggested by Appendix B). In order to obtain coordinated and consistent graphic symbols, reference symbols and reference symbol libraries can be referenced. Most of the graphic symbols in GB/T4728 and ISO14617 can be used as the basis for such reference symbols.
e) Since the graphic symbols in the referenced standards do not specify additional requirements for their effective use in computer-aided design systems, this 5
GB/T16901.2-2000
standard specifies the CAx requirements to be met for this purpose, see Appendix A (indicative appendix) for details. f) The use of reference symbols helps
to have a common understanding of the use of reference symbol libraries within application software; to reuse common functional or product concepts when working in a multi-vendor environment; an effective exchange mechanism for symbols for schematics; the effectiveness of symbol definitions;
to maintain good and adequate quality while increasing support for automated design concepts: to support the reuse of graphic symbols at different stages of a series of processes with minimal size changes and graphic symbol adjustments; to expand the existing functions of CAx systems.
6 Symbol (including symbols in the reference symbol library) provisions 6.1 General
The reference symbols should be determined in accordance with the following supplementary rules of GB/T16901.1 and this standard. The rules of this standard also apply to the production of graphic symbols outside the reference symbol library.
A reference symbol may be equipped with some spaces with a certain position to express data associated with the object represented by the graphic symbol in the diagram. In this standard, the content of these spaces will be represented visually in the text area. Appendix E (Standard Appendix) gives the recommended values ​​of data types and lengths for the spaces determined by this standard. Notes
1 Unless otherwise specified, the dimensions given in this standard are determined by the center line of the drawing, the center of the circle, etc. 2 The minimum distances specified in this standard meet the requirements specified in GB/T16901.1, while taking into account the existing mechanical errors of printing equipment and drawing equipment. 6.2 Graphical Symbol Variants
6.2.1 General
Considering the control (information, signal flow) and process (matter, energy) flow of the graphic symbol itself, it may be necessary to use up to eight different variations of the graphic symbol in a schematic diagram if the reading direction of the characters or other labels associated with the graphic symbol is parallel to the control flow. In determining these variations, this standard does not make further provisions for the use of these eight variations in schematic diagrams. Regardless of whether they are used or not, these variations are individually named in alphabetical order from A to H.
Figure 3 describes the definition of these variations.
Control
Process Flow
Process Flow
Process Flow
Control Control flow
Proof process flow
Various variants of graphic symbols in Figure 3
In order to clearly define the variant names, the following rules must be followed: 6
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-If there is only one flow direction and it is unclear whether it is control flow or process flow (such as resistors, capacitors, contactors), the control flow should be considered;
-If the control flow is parallel to the process flow, the control flow should be given priority; If two or more variants are the same in the diagram, the names of these variants should be arranged in alphabetical order starting from A, and the variant at the front should be selected according to the arrangement result. Note: The above rules can be used as the basic rules for defining graphic symbol variants. Based on uncertainty Specific variants may be excluded due to reasons such as sex or economy. At this time, the relevant national standards for the graphic symbols should list the permitted variants in accordance with the rules determined in this standard. 6.2.2 Examples of variants of graphic symbols
Figures 4, 5 and 6 list examples of variants of graphic symbols. 4
Examples of various variants of the graphic symbol representing thyristor 2
Variant name.ACE, GA
Variant name.B, D, F.HB
Figure 5 Examples of various variants of the graphic symbol for variable resistor, which lists the terminal code for the product 2
Variant name; A, CE, G-→A
Variant name: BDF, H-→B
Figure 6 Examples of various variations of graphic symbols for resistors Note: The expression of graphic symbols in the current version of GB/T4728 is inconsistent with these variations. 6.2.3 Variations of composite graphic symbols
GB/T16901.2-2000
Compound graphic symbols that include the expression of operating devices, operating methods and mechanical control linkages (such as mechanical, pneumatic, hydraulic connections, etc.) should be determined according to variant A with connections, and the effects of control flow should be considered from left to right in the order shown in Figure 7. Note: This method greatly reduces the number of symbols stored in the reference symbol library. The graphic symbols in the current version of GB/T4728 do not take this aspect into account.
Figure 7 Graphic symbol for delayed action
6.3 Scale
When scaling the graphic symbols in GB/T4728 and ISO14617, the scale factor should be the same in the direction of the axis coordinates. When modifying the symbol size, the symbol as a whole should be modified with the same scale factor according to the original relationship between the various parts of the symbol and the reference point. The line width and grid modulus M remain unchanged (see Figure 8). rh2
Figure 8 Example of enlarging a graphic symbol using a scale factor of 2:1 For the exchange of simplified diagrams and reference symbol libraries, the scale factor information used should be transmitted. 6.4 Modular size of the reference symbol library
All graphic entities of the same reference symbol should be in modulus M. For the exchange of simplified diagrams and reference symbol libraries, the information of the modulus M used should be transmitted. Note: The modification of the modulus value means the modification of all graphic entities (see Figure 9). In order to better apply the standard line width specified in GB/T17450, it is recommended to select the modulus M series values ​​from Table 1: Table 1 Modulus M series values
Modulus M
Unit: mm
1) 1.8mm is a value specified in GB/T17450, but in order to be easily recognizable on the computer screen, it is recommended not to use a modulus value less than 2mm. In addition to the above series values, the modulus value of 2mm is also used in computer graphics, so Table 2 adds the 2mm modulus value to the series value of modulus M and lists the line width values ​​corresponding to modulus M. Table 2 Modulus M and its corresponding line width d series values ​​Modulus M
Line width a
(d=1/10m)
Unit: mm
Note: In actual application, a physical value must be selected for modulus M. Since the processing of documents such as microfilm, reduced/unreduced photocopy, fax, etc. adopts different forms, the readability of the documents must also be considered. For microfilm, the provisions of GB/T10609.4 must be followed.
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