Application Protocols
- Components of an Application Protocols
- Which advantages do Application Protocols offer?
An Application Protocol (AP) includes a standardized representation of product data in a specific application context. Thus the scope of each AP must be defined precisely. This includes
- The description of the functionality (AAM, Application Activity Model)
- An application-oriented reference model from a user's point of view (ARM, Application Reference Model)
- Representation of the reference model through objects from the Integrated Resources as implementation view (AIM, Application Interpreted Model) and
- Implementation guidelines and conformance conditions for implementations
The documentation of an Application Protocol adheres to strict regulations. The specification uses the description language EXPRESS as well as the Integrated Resources. The resulting data model (AIM) for an AP is the basis for all its implementations.
For the description of the product data model for a specific application, not all the elements defined in the Integrated Resources are required. On the other hand, the generic constructs of the basic models need to be put into the context of the application, which is realized through the definition of rules and specializations for the objects of the basic models. The Application Protocols (ISO 10303-2xx) are such branch- resp. application-specific product data models in STEP.
Currently, 33 drafts for Application Protocols are in the standardization process.
We can provide you with detailed information on the following Application protocols:
- AP203 (Configuration Controlled Design)
- AP212 (Electrotechnical Design and Installation)
- AP214 (Core Data for Automotive Mechanical Design and Processes)
We offer a short overview for the other APs. Components of an Application Protocol.
An Application Protocol consists of the following components:
1. Functional model of the application which is supported by the product data model. The AAM serves the definition of the standard's scope. The AAM is defined using the SADT method, and describes the application through processes. In the AAM, the dataclasses which identify the input, output, method or parameters of the functions in focus are identified.
2. The product data model describes the data classes identified in the AAM and their relationships to each other from a user's point of view. Usually, EXPRESS-G is used for this purpose. Every object of the product data model needs to be defined explicitly, including all its attributes and relationships.
3. The standardized product data model is an information model, which uses the pre-defined building blocks from the Integrated Resources in the context of the specific application. Therefore, a Mapping is specified between the data objects of the ARM and those of the AIM.
4. Especially in bigger application models, it makes sense to subdivide the data classes into Units of Functionality (UoF). Not every implementation of an AP will always use all defined objects. In order to avoid conflicts, allowed partial models of an AP are defined, based on the UoFs - the so-called Conformance Classes. These have to be implemented completely. At the same time, they establish the basis for possible certifications (e.g. of processors).
Note: From this follows that for an implementation of a STEP Application Protocol (e.g. STEP processors for data exchange), it is not sufficient to merely state the Application Protocol, in fact also the implemented Conformance Class(es) need to be specified.
If during the development of application protocols scopes are defined which are identically mapped in two or more APs, the definition of so-called Application Interpreted Constructs (AIC) is possible. AICs define the overlapping scopes of several APs. They are lodged as the 500-series of the ISO 10303 standard.
Which advantages do Application Protocols offer?
The more application-oriented an Application Protocol is, the sooner it will assert itself in practical utilization. The requirement can only be accomplished, if specialists are involved in the whole development process. This happened intensively e.g. during the development of the APs 212 and 214. At the same time, aspects of the standards have been tested in implementations at an early stage.
The Application Protocols AP212 and AP214 represent widespread information models for different process chains. Since they describe all relevant data for the design- and construction processes within the automotive and electrical industry, they can, as a basis for operational information systems, offer significant strategic advantages to the manufacturers and suppliers in these branches. These advantages, which can be transfered to nearly all STEP applications, consist among others of:
- System independence,
- Data continuity throughout the complete product lifecycle,
- Redundance-free product data representation,
- Higher quality of the product data through formal representation following standardized methods,
- Qualitative better product data exchange and
- Feasability of long-term archiving.
These advantages become outstandingly clear when taking into account, that the german automakers and their 900 suppliers alone use about 110 different CAD systems. Due to the heterogeneous system scenery and the currently inadequate interface formats, a costly manual postprocessing of the transferred data is necessary.The development of an Application Protocol towards an International Standard is very elaborate. This explains why not every proposition to develop an AP came to a successful ending.The following table shows the current status of the Application Protocols which have been developed resp. still are under development:
ISO 10303 | Name | Status 05/02 |
201 | Explicit draughting | IS |
202 | Associative draughting | IS |
203 | Configuration controlled design | IS |
204 | Mechanical design using boundary representation | FDIS |
207 | Sheet metal die planning and design | IS |
208 | Life-cycle product change process | canceled |
209 | Composite and metal structural analysis and related design | IS |
210 | Electronic assembly, interconnection and packing design | IS |
212 | Electrotechnical design and installation | IS |
213 | Numerical control (NC) process plans for machined parts | canceled |
214 | Core data for automotive mechanical design processes | IS |
215 | Ship arrangement | CD |
216 | Ship moulded forms | CD |
218 | Ship structures | CD |
220 | Process planing, manufacturing assembly of layered electrical products | recommended |
221 | Functional data and their schema representation for process plants | CD |
223 | Exchange of design and manufacturing product information for cast parts | canceled |
224 | Mechanical parts definition for process planing using machining features | IS |
225 | Building elements using explicit shape representation | IS |
226 | Ship mechanical systems | CD |
227 | Plant spatial configuration | IS |
232 | Technical data packaging: core information and exchange | FDIS |
233 | Systems engineering data representation | canceled |
234 | Ship operational logistics, records and messages | WD |
235 | Materials information for design and verification of products | WD |
236 | Furniture product and project data | WD |
237 | Computational fluid dynamics | WD |
238 | High level information planing model for product l-c spt | recommended |
IS - International Standard
FDIS - Final Draft International Standard
DIS - Draft International Standard
CD - Committee Draft
WD - Working Draft
Latest status see: http://www.nist.gov/sc5/soap/