ISO TC184 SC4
STEP on a Page
ISO 10303
STEP on a Page provides a graphic summary of the progress of STEP, Standard for the Exchange of Product Model Data, the familiar name for ISO 10303. STEP is developed by ISO TC184 SC4, Industrial-Automation Systems and Integration, Industrial Data
Status of STEP Parts
Every part shown in the STEP on a Page has its status shown beside it. The status designators vary from "O" (the ISO preliminary stage) to "I" (international standard--the most advanced stage of standards development and acceptance). Parts designated as "E, F" (levels of draft international standard) and "I" are considered advanced enough to allow software vendors to prepare implementations. The legend at the bottom of the page lists the corresponding ISO project stage numbers next to the letter code.
Architecture of STEP and STEP on a Page
STEP on a Page attempts to show the STEP architecture by grouping the STEP parts into five main groupings--description methods, integrated-information resources, application protocols, implementation methods, and conformance methodology.
From an architectural perspective, the description methods group forms the underpinning of the STEP standard. This includes part 1, Overview, that also contains definitions that are universal to the STEP. Also in that group, part 11, EXPRESS Language Reference Manual, describes the data-modeling language that is employed in STEP. Parts in the descriptive-methods group are numbered from 1 to 19.
At the next level is the integrated-information-resources group, the parts that contain the actual STEP data models. These data models can be considered the building blocks of STEP. Integrated-information resources are subgrouped into generic resources, application resources, and application-interpreted constructs or AICS. Integrated-generic resources are generic entities that are used as needed by application protocols (APs) described below. Parts within generic resources are numbered in the 40s and are used across the entire spectrum of STEP APs. The integrated-application resources contain entities that have slightly more context than the generic entities. The parts in the integrated-application resources are numbered in the 100s. Because entities in the integrated-resources group are shareable across the application protocols that need them, they can help enable AP integration and interoperability.
The 500 series are application-interpreted constructs, AICs. These are reusable groups of information-resource entities that make it easier to express identical semantics in more than one AP.
At the top level of the STEP hierarchy are the more complex data models used to describe specific product-data applications. These parts are known as application protocols and describe not only what data is to be used in describing a product, but how the data is to be used in the model. The APs use the integrated-information resources in well-defined combinations and configurations to represent a particular data model of some phase of product life. APs are numbered in the 200s. APs currently in use are the Explicit Draughting AP 201 and the Configuration Controlled Design AP 203.
Implementation & Conformance
The STEP implementation-methods group, the 20s series, describe the mapping from STEP formal specifications to a representation used to implement STEP.
The conformance-testing-methodology framework group, the 30s series, provides information on methods for testing of software-product conformance to the STEP standard, guidance for creating abstract-test suites, and the responsibilities of testing laboratories. The diagram shows that part 31, which describes the methodology to perform conformance testing, has been approved as an international standard. The STEP standard is unique in that it places a very high emphasis on testing, and actually includes these methods in the standard.
Abstract Test Suites
The 300 series of parts, abstract-test suites, consists of test data and criteria that are used to assess the conformance of a STEP software product to the associated AP. SC4 requires that every AP contain or be associated with an abstract-test suite. The numbers assigned to ATSs exceed the AP numbers by exactly 100. Therefore, ATS 303 applies to AP203. On the graphic, the ATS status is shown in parentheses following the AP name.
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STEP on a Page was conceived and implemented by Jim Nell, National Institute of Standards and Technology. 98-Aug-05
