ISO 10303-28-2007 PDF

Full title and description

ISO 10303-28:2007 — Industrial automation systems and integration — Product data representation and exchange — Part 28: Implementation methods: XML representations of EXPRESS schemas and data, using XML schemas. This part of the STEP family (ISO 10303) specifies how EXPRESS schemas and EXPRESS-governed data are represented using XML and XML Schema constructs (often referred to as STEP‑XML / EXPRESS‑X).

Abstract

Specifies the rules, XML-Markup declaration sets and mapping conventions required to represent EXPRESS schemas and their instance data in XML, including both schema‑specific (early bound) and schema‑independent (late bound) XML representations, and the representation of EXPRESS primitive types in XML content and attributes.

General information

• Status: Published (International Standard; confirmed on review cycles).
• Publication date: October 2007 (2007-10).
• Publisher: International Organization for Standardization (ISO).
• ICS / categories: 25.040.40 (Industrial process measurement and control / product data representation and exchange).
• Edition / version: Edition 1 (2007).
• Number of pages: 309.

Core bibliographic and status details from the ISO catalogue entry for ISO 10303‑28:2007.

Scope

Defines how an XML representation described by an XML Schema can be used to exchange data described by an EXPRESS schema. Within scope are the late‑bound (generic) and early‑bound (schema‑specific) XML markup declaration sets, the mapping conventions between schema‑specific and schema‑independent markup, the permitted forms of XML documents that carry EXPRESS schemas and/or EXPRESS‑governed data, and rules for representing EXPRESS primitive data types in XML. The standard explicitly excludes mappings that depend on semantic intent (i.e., semantic reinterpretation of data) and mappings back to the original EXPRESS schema in a general way.

Key topics and requirements

• Definition of XML markup declaration sets for EXPRESS schemas: both late‑bound (generic) and early‑bound (schema specific).
• Mapping rules between EXPRESS constructs (types, entities, selections, aggregates) and XML Schema constructs (elements, attributes, complex/simple types).
• Guidance for document forms that contain EXPRESS schemas and/or instance data, including namespace and schema location conventions.
• Representation of EXPRESS primitive data types (integers, reals, strings, enums, logical, etc.) as XML element content or attributes.
• Conformance guidance for implementers producing or consuming STEP‑XML (EXPRESS‑X) documents.
• Out‑of‑scope clarifications: semantic mappings that require domain knowledge and automated reverse‑mapping from XML back to the original EXPRESS schema are not covered.

Typical use and users

Used by CAD/CAM/CAE software vendors, PLM and PDM system integrators, data‑archiving and long‑term preservation projects, implementers of STEP converters and middleware, and organizations that exchange STEP data via XML rather than STEP‑File format. Typical tasks include creating STEP‑XML exporters/importers, generating XML Schemas from EXPRESS schemas, validating STEP‑XML documents and implementing data interchange workflows between engineering systems.

Related standards

Part of the ISO 10303 (STEP) series. Closely related items include ISO 10303‑11 (EXPRESS language and schema definitions), ISO 10303‑21 (STEP‑File clear text encoding), ISO 10303‑1 (overview and principles of the STEP family) and many application protocols (APs) that define domain models expressed in EXPRESS (for example AP203 / AP214 / AP242 and others). ISO 10303‑28 superseded the earlier technical specification ISO/TS 10303‑28:2003.

Keywords

ISO 10303, STEP, EXPRESS, STEP‑XML, EXPRESS‑X, XML Schema, data exchange, CAD, product data representation, PLM, PDM, XML representation of schemas.

FAQ

Q: What is this standard?

A: ISO 10303‑28:2007 is the STEP implementation method that defines how EXPRESS schemas and their instance data are represented using XML and XML Schema (commonly called STEP‑XML or EXPRESS‑X).

Q: What does it cover?

A: It covers the XML markup declaration sets (late‑bound and early‑bound), mapping rules from EXPRESS to XML Schema constructs, document forms for carrying schemas and data, and representation of EXPRESS primitive types in XML. It does not define semantic reinterpretation rules or automatic reverse mapping back to original EXPRESS schema meanings.

Q: Who typically uses it?

A: Software vendors, system integrators, PLM/PDM specialists, data‑exchange implementers, and organizations needing STEP data exchange or archival in XML form.

Q: Is it current or superseded?

A: The published edition is Edition 1 (2007). The ISO catalogue entry shows the publication date as October 2007 and indicates the document was reviewed and confirmed in subsequent review cycles (confirmed in 2024), so the 2007 edition remains the current ISO publication for Part 28.

Q: Is it part of a series?

A: Yes — it is Part 28 of the ISO 10303 family (STEP). The family includes description methods (EXPRESS), implementation methods (STEP‑File, STEP‑XML, SDAI, language bindings), application protocols (APs) and many resource and module parts. ISO 10303‑28 specifically addresses the XML implementation method for EXPRESS.

Q: What are the key keywords?

A: EXPRESS, STEP, STEP‑XML, EXPRESS‑X, XML Schema, product data, CAD/CAM/CAE, data exchange, PLM, PDM.