ISO 15926
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The ISO 15926 is titled: "Industrial automation systems and integration -- Integration of life-cycle data for process plants including oil and gas production facilities"
This title is regarded too narrow by the present ISO 15926 developers. Having developed a generic data model and Reference Data Library for process plants it turned out that this subject is already so wide, that actually any state information may be modelled with it.
ISO 15926 is a standard for data integration, sharing, and exchange between computer systems.
Contents |
[edit] The standard
ISO 15926 has 7 parts:
- Part 1 - Introduction, information concerning engineering, construction and operation of production facilities is created, used and modified by many different organizations throughout a facility's lifetime. The purpose of ISO 15926 is to facilitate integration of data to support the lifecycle activities and processes of production facilities.
- Part 2 - Data Model. a generic 4D model that can support all disciplines, supply chain company types and life cycle stages, regarding information about functional requirements, physical solutions, types of objects and individual objects as well as activities.
- Part 3 - Geometry and Topology, defining, in OWL, the geometrical constructs of ISO 10303-42.
- Parts 4,5,6 - Reference Data, the terms used within facilities for the process industry.
- Part 7 - Implementation methods for the integration of distributed systems, defining an implementation architecture that is based on the W3C Recommendations for the Semantic Web.
[edit] Description
The model and the library are suitable for representing lifecycle information about technical installations and their components.
They can also be used for defining the terms used in product catalogs in e-commerce. Another, more limited, use of the standard is as a reference classification for harmonization purposes between shared databases and product catalogues that are not based on ISO 15926.
The purpose of ISO 15926 is to provide a Lingua Franca for computer systems, thereby integrating the information produced by them. Although set up for the process industries with large projects involving many parties, and involving plant operations and maintenance lasting decades, the technology can be used by anyone willing to set up a proper vocabulary of reference data in line with Part 4.
In Part 7 the concept of Templates is introduced. These are semantic constructs, using Part 2 entities, that represent a small piece of information. These constructs then are mapped to more efficient classes of n-ary relations that interlink the Nodes that are involved in the represented information.
These Node and Template instances are stored in Façades. A Façade is an RDF quad store, set up to a standard schema and API, as defined in Part 7. Any Façade only stores the data for which the Façade owner is responsible.
The Façade API has methods for:
- population = entering instances of Nodes and Templates in a Façade contained in a Transfer File, thereby keeping that Façade in sync
- hand-over = physically moving instances of Nodes and Templates from one Façade to another
- exchange = sending a Message containing one or more Documents from one Façade to another
- query = fetching data from one or more Façades for display on an Ontology Browser or for use in a participating computer system
Each participating computer system maps its data from its internal format to such ISO-standard Node and Template instances. These are stored in a System Façade, each system its own Façade.
Data can be "handed over" from one Façade to another in cases where data custodianship is handed over (e.g. from a contractor to a plant owner, or from a manufacturer to the owners of the manufactured goods). Hand-over can be for a part of all data, whilst maintaining full referential integrity.
Façades can be set up for the consolidation of data by handing over data produced by various participating computer systems and stored in their System Façades. Examples are: a Façade for a project discipline, a project, a plant, or even for a company in a fiscal year).
Documents are user-definable. They are, in essence, only a structure containing cells that make reference to instances of Templates. This represents a view on all lifecycle data: since the data model is a 4D (space-time) model, it is possible to present the data that was valid at any given point in time, thus providing a true historical record. It is expected that this will be used for Knowledge Mining.
Data can be queried by means of SPARQL. In any implementation a restricted number of Façades can be involved, with different access rights. This is done by means of creating a matrix called a CPF (= Confederation of Participating Façades). An Ontology Browser allows for access to one or more Façades in a given CPF, depending on the access rights.
[edit] Projects
At present (spring 2006) two cooperating implementation projects are being set up:
- The ADI Project of FIATECH (www.fiatech.org), to build the tools (which will then be made available in the public domain)
- The IDS Project of POSC/Caesar (www.posccaesar.org), to define product models required for data sheets
[edit] History
In 1989 a European Union-funded project, named ProcessBase, started. The focus of this research project was to develop a data model for lifecycle information of a facility that would suit the requirements of the process industries.
At the time that the project duration had elapsed a consortium of companies involved in the process industries had been established: EPISTLE (European Process Industries STEP Technical Liaison Executive). Initially individual companies were members, but later this changed into a situation where three national consortia were the only members: PISTEP (UK), POSC/Caesar (Norway), and USPI-NL (Netherlands). (later PISTEP merged into POSC/Caesar, and USPI-NL was renamed to USPI).
EPISTLE took over the work of the ProcessBase project. Initially this work involved a standard called ISO 10303-221 (referred to as "AP221"). In that AP221 we saw, for the first time, an Annex M with a list of standard instances of the AP221 data model, including types of objects. These standard instances would be for reference and would act as a knowledge base with knowledge about the types of objects. In the early nineties EPISTLE started an activity to extend Annex M to become a library of such object classes and their relationships: STEPlib. In the STEPlib activities a group of approx. 100 domain experts from all three member consortia, spread over the various expertises (e.g. Electrical, Compressors, etc), worked together to define the "core classes". This work was extended by the integration of many of the concepts from AP221 and ISO 15926-2 into STEPlib, resulting is an integrated data exchange language, called Gellish.
For modelling-technical reasons POSC/Caesar proposed another standard, called ISO 15926. EPISTLE (and ISO) supported that proposal, and continued the modelling work, thereby writing Part 2 of ISO 15926. This Part 2 has official ISO IS (International Standard) status since 2003.
POSC/Caesar started to put together their own RDL (Reference Data Library). They added many specialized classes, for example for ANSI (American National Standards Institute) pipe and pipe fittings. Meanwhile STEPlib continued its existence, mainly driven by some members of USPI-NL. Since it was clear that it was not in the interest of the industry to have two libraries for, in essence, the same set of classes, the Management Board of EPISTLE decided that the two libraries shall be merged into Part 4 of ISO 15926. This merging process has still not been finished. Part 4 should act as reference data for part 2 of ISO 15926 as well as for ISO 10303-221 to replace its Annex M. ISO 15926-4 has been sent to ISO for its first ballot. Work is being done to prepare it for ballot as a TS (Technical Specification).
In 1999 the work on Part 7 started. Initially this was based on XML Schema (the only useful W3C Recommendation available then), but when OWL became available it was clear that that provided a far more suitable environment for Part 7. Part 7 passed the first ISO ballot by the end of 2005, and an implementation project starts. On the basis of that a formal ballot for TS (Technical Specification) is planned for December 2006.
[edit] Some technical background
One of the main requirements was (and still is) that the scope of the data model covers the entire lifecycle of a facility (e.g. oil refinery) and its components (e.g. pipes, pumps and their parts, etc.). Since such a facility over such a long time entails many different types of activities on a myriad of different objects it became clear that a generic and data-driven data model would be required.
A simple example will illustrate this. There are thousands of different types of physical objects in a facility (pumps, compressors, pipes, instruments, fluids, etc). Each of these has many properties. If all combinations would be modelled in a "hard-coded" fashion, the number of combinations would be staggering, and unmanageable.
The solution is a "template" that represents the semantics of: "This object has a property of X yyyy" (where yyyy is the unit of measure). Any instance of that template refers to the applicable reference data:
- physical object (e.g. my Induction Motor)
- indirect property type (e.g. the class "cold locked rotor time"
- base property type (here: time)
- scale (here: seconds)
Without being able to make reference to those classes, via the Internet, it will be impossible to express this information.
[edit] Warnings
- Against Idiosyncrasy in Ontology Development: A critical study of ISO 15926 and of the claims made on its behalf.
- Wüsteria: A critical study of ISO terminology standards.