Communication standards between systems

There are the following standards for data exchange between systems: IGES, DXF, ISO 10303 (STEP), ISO 13584 (P_LIB), ISO 15531 (MANDATE), ISO 8879 (SGML), ISO 18876 IIDEAS, EIA 649 [9, 19].

The IGES standard (Initial Graphics Exchange Specification) is the initial specification for the exchange of graphic data. IGES was the first standard format for data exchange between different CAD systems. In 1981, the format description was adopted by the American National Standards Institute (ANSI) as a standard.

Depending on the version, the IGES standard allows the exchange of drawings, finite element analysis data, PCB data, 3D geometry descriptions, etc.

DXF standard (Drawing interchange Format) is a drawing interchange format. It was originally developed to give users the flexibility to manage data and convert AutoCAD drawings into file formats that could be read and used by other CAD systems. Due to the popularity of the AutoCAD system, the DXF format has become the de facto standard for exchanging drawing files for almost all CAD systems.

A DXF file is an ASCII text file consisting of five sections: Header (header), Table (table), Block (block), Entity (element), Terminate (end). Data for each drawing element is stored in the main Entity section.

ISO 10303 STEP ( Standard for the Exchange of Product Model Data) is an international standard for the computer representation and exchange of product data. The purpose of the standard is to provide a neutral mechanism for describing product data at all stages of its life cycle, independent of a particular system. The nature of this description makes it suitable not only for a neutral exchange file, but also as a basis for the implementation and dissemination of product databases, as well as for archiving.

It defines the means of describing (modeling) industrial products at all stages of their life cycle. The basis for creating a unified information environment in industrial systems is the application-invariant Express language introduced in STEP.

The ISO 10303 standard consists of a number of documents (volumes), each of which can be considered as an independent standard, i.e. STEP is actually a group of standards. The STEP volumes describe the basic principles of data exchange, set out the rules of the Express language. The documents give methods for its implementation, models, methods for testing models, resources both general for applications and some special ones (for example, geometric and topological models, description of materials, drawing procedures, finite element analysis, etc.). In addition, application protocols have been introduced that reflect the specifics of models in specific subject areas. The main attention is paid to the issues of interaction of automated systems in STEP – a subgroup of volumes is allocated, which is devoted to methods of data exchange between different systems created within the framework of STEP technology.

The ISO 13584 P_Lib (Parts Library) standard provides an overview and basic principles for building libraries with data on standard components for industrial products. The standard provides information on families of such typical widely used product components as bolts, bearings, electronic components and others, in order to use this data in computer-aided design systems. P_Lib also contains rules for the use, interface, and modification of library definitions. The purpose of the standard is to provide an application-invariant mechanism for operating parts of a library.

Thanks to P_Lib, various CAD applications can share data from generalized databases and freely exchange data about typical components. The P_Lib standards consist of several parts. Part 1 is an overview and main provisions of a series of standards. Parts 10-19 contain the conceptual provisions for building component libraries. Sections 20-29 are dedicated to describing logical resources. Parts 20, 24, and 26 are developed here, describing the shared resources, the logical model of the supplied library, and identifying component providers. Parts 30-39 are used to describe deployment resources. Part 31, dedicated to the Geometric Programming Interface, has been developed here. A description of the methodology for structuring families of components is contained in Part 42. Part 101 contains a protocol for the exchange of geometric parameterized information. Part 102 is a protocol for the exchange of data consistent with STEP.

ISO 15531 MANDATE ( Man ufacturing Data a for E xchange) is a standard for the exchange of manufacturing data. The standard is devoted to the presentation of data related to the functioning of enterprises, the management of geographically distributed production systems, the exchange of production data with the environment external to the enterprise.

The part of the standard referred to as ISO 15531-21 provides an overview and basic principles for the presentation of industrial product data. The content of this part is characterized by the following key concepts: “industrial automation systems and integration”, “industrial data”, “data exchange about production management”, “data exchange with the external environment”. Volume ISO 15531-31 is devoted to an overview and basic principles for the use of data on production resources. The model, form and attributes of the presentation of data on production resources, on the management of their use are described. ISO 15531-41 volume provides an overview and basic principles of manufacturing data flow management.

ISO 8879 (SGML) standard. Due to the variety of ways to present textual and graphic information associated with the use of heterogeneous software tools, text formatting and layout technologies, encoding methods and support for national languages, there is a need to develop unified solutions. Such a solution is contained in the ISO 8879 (SGML, Standard Generalized MarkUp Language) standard, which defines a “generalized standard markup language” for text.

The technology of electronic markup of text, based on the insertion of special marks into the text, is widely used in modern software tools for layout and formatting. The ISO 8879 SGML standard defines how a document’s structure is described, as well as the format of descriptive labels inserted into a document, but does not define the format of document style data. The structure of a document is specified by a “document type definition” (in terms of the standard – Document Type Definition or DTD for short), which describes the structure of the document in the same way that a database schema describes the types of data supported and the relationships between fields. A Document Type Definition (DTD) defines the relationships between chapters, chapter headings, sections, and other pieces of text that make up a document. In addition, the DTD specifies rules for relationships between document elements. The rules contained in the DTD allow you to automatically control the correctness of the logical structure of the document. In addition to text and graphic information, multimedia elements can be inserted into an SGML document: audio and video recordings.

ISO 18876 IIDEAS standard . SC4 WG10 developed the ISO 18876 IIDEAS standard. Its purpose is to ensure the interaction of applications and organizations that use different standards, the integration of data and models obtained from different sources, developed in different CAD systems. Possibilities are provided for coordinating models expressed using different modeling languages and formats, for example, such as SGML, XML, Express. Integration tools – special integration models and methods for creating, distributing, updating models, their connection with application protocols.

The EIA 649 standard deals with product configuration management. It establishes the basic principles of configuration management and the rules for managing changes to documentation. In addition, it addresses issues such as document identification, product and data configuration relationships, data versioning and data access control, etc. The standard introduces data status levels to which a document belongs at one or another stage of its life cycle. Levels of working, released, submitted and approved data are possible. At the level of working data, its compiler (developer) works with the document. At the released data level, the document is available to the relevant departments of the manufacturing organization. Any change in data requires special conciliation procedures. The presented data is already available for viewing by customers (consumers). The status of “approved” data is received after approval by the customer.

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