On a broad foundation of standards

Standardisation is now more than ever an important instrument in competing internationally.

It supports the introduction into the market and success of new technologies, such as fieldbus technology, and at the same time lowers the risk for related investments.

Active cooperation in standards committees has consequently been a strategic pursuit of Profibus International (PI) from the beginning with the result that the Profibus/Profinet automation technologies are today based on a broad foundation of international standards - a huge advantage for users as well as manufacturers.

International standardisation customer orientation, quality, cost effectiveness and time to market are keys to a company's success in the market.

There is one concept missing from this list, although it describes what in many cases functions in the background as a cause for market success: international standardisation.

For example, operating efficiency can often only be achieved through company-wide division of labour or cost-effective plant engineering and operation through the compatibility of the components and systems used (different manufacturers).

Standardisation describes the sum of all measures taken to unify technologies, processes and even interfaces or products on a defined level to ensure compatibility and interoperability.

The results of standardisation are primarily technical standards, but also industry standards or consortia standards compiled by consortia.

De Jure Standards are documents based on the consensus of all groups concerned (industry, consumers, legislators, etc).

They contain a well-known, legally recognised specification compiled in a standardisation procedure for the resolution of an issue.

Standards must be technically mature and be of use to the user.

Synonymous with the German concept of standard 'Norm' is the English concept of 'de jure standard'.

Industry standards (de facto standards) are pragmatic regulations that have proven themselves technically useful and sensible through long-standing practice by users and manufactures without any national or international standardisation procedure.

Widespread industry standards are described as 'de facto standards'.

Consortia standards are developed by manufacturers and users who are pursuing a common standardisation objective and who affiliate in consortia (eg Profibus International) in order to arrive at common solutions in a shorter period of time.

Open standards are generally available documents and are therefore independent from any particular manufacture (non-open standards are described as proprietary).

Standards are in any case open; industry and consortia standards are open, if the specifications are freely available.

The consortia standards of Profibus International are open standards.

They are available to anyone interested.

International standards, primarily implemented by the IEC (International Electrotechnical Commission) and ISO (International Standardisation Organisation), have very quickly gained importance in terms of their globalisation compared to national or even European standards.

International standards help to break down trade barriers, open new markets and reduce costs to name their key advantages.

Details follow in a later paragraph.

Standards should answer a problem of general interest more or less in the form of abstract specifications; not specify any concrete technical implementations, but rather leave various approaches open; and be supported by sufficient market strength.

Manufacturers are left to find and develop suitable approaches, in which the possibilities of competition and creation of unique selling propositions (driven by the market) are encouraged.

In practice, the approach of a generally formulated requirement leads from an international standard to the realisation of a tangible answer, and then to a device.

Functional safety and electromagnetic compatibility (EMC) are, for example, very abstract, but are in part law.

They cannot be implemented without precise specifications.

Overview documents have the characteristic of a manual, eg for the abstract requirements on the building blocks in the process industry.

They are only conditionally suitable for implementation and are primarily used for additional standards as a requirement for what should be standardised, but not how.

Specifications and concepts describe product requirements that are most often tested with a conformance test for adherence to the requirements, eg the programming languages from IEC 61131-3 or the Electronic Device Description Language (EDDL) from IEC 61804-2.

Interface specifications between different devices must be formulated in great detail.

Even the languages are accurately described, but used on an abstract level.

Interfaces describe eg communication interfaces between devices that exchange information.

Guidelines with acceptability for implementation are not preferred in international standardisation.

The creation and publication of guidelines (eg for implementations) are left to consortia, institutes or businesses.

Note: Guidelines should not be confused with IEC guides, which represent instructions for the standards in the technical committees.

Device documentation is left to the market, more specifically the manufacturers.

Standardisation of fieldbus technology.

The standardisation of fieldbus technology goes back to the year 1984, when the decision was made in Germany to make a New Work Item Proposal at the IEC called 'fieldbus'.

The result was the establishment of IEC Project 61158 and in close cooperation with several groups, including the USA, very quickly specified the physical layer and described it in IEC document 61158-2.

It turned out to be very difficult to reach a consensus on the data link layer and the related application layer.

Contrary opinions existed between participating work groups about the appropriate access method (centralised or decentralised).

Consensus could not be reached even with suggestions of compromise.

Ultimately, different paths were taken on a regional basis to continue the work, which resulted in eg the German standard DIN 19245 in 1991 and the European standard EN 50170.

In the end, an international agreement was reached, although with certain restrictions: the idea of creating a single international fieldbus was dropped in favour of a pragmatic solution appropriate for existing market conditions.

The decision was made in 1999 to allow several fieldbuses under one standard and consequently, in addition to the unchanged IEC 61158-2 capable of consensus, to expand sections IEC 61158-3 to 61158-6 with additional specifications under the designation Protocols and Services.

IEC 61158 is divided into six parts.

An introduction in part 1 - structured in accordance with the ISO/OSI 7 layer model - in parts 2 through 6 the specifications of numerous services and protocols for communication between bus devices.

IEC 61158 copes with the historical existence of several different fieldbus systems by considering ten 'fieldbus protocol types' with Profibus as type 3 and Profinet as type 10.

IEC 61158 specifically states that bus communication is only possible between bus devices that belong to the same protocol type.

The services and protocols of IEC 61158 (and other standards) are used as a total available set from which a specific selection is defined for communication for certain fieldbus systems (subset).

The selection is normally defined by referencing, not by repeated comprehensive detailed descriptions.

The subsets are described as communication profiles and organised by their association in Communication Profile Families (CPF).

The communication profile sets used with Profibus and Profinet are combined in Family 3 (CPF 3).

Respective IEC 61158 protocol types CPF 1; Foundation Fieldbus; 1, 5, 9 CPF 2; ControlNet; 2 CPF 3; Profibus; 3, 10 CPF 4; P-Net; 4 CPF 5; WorldFIP; 7 CPF 6; Interbus; 8 CPF 7; SwiftNet.

Profibus International, to which the Profibus Nutzerorganisation PNO) (established in 1989) belongs, today has more than 1200 members (manufacturers and users).

Its goal is to propagate fieldbus technology developed in cooperation among member companies, to support its users and to ensure continued development.

In the interests of its members, from the beginning PI has pursued the objective of basing this new automation technology on international standards where appropriate, be it through the use of already existing standards or through intensive cooperation in the creation of new standards.

As a result, an extraordinarily wide and stable foundation of standards has been created for Profibus and the ethernet-based technology Profinet over the years, something of paramount importance for users and manufacturers in terms of investment security and their future use.

Specific Application Profiles; IEC 61804-2; Specification of FB concept and Electronic Device Description Language (EDDL); IEC 61800-7; Generic Drive Interface General Application Profiles; IEC 61784-3; Profiles for functional safe communications in industrial networks; IEC 61784-4; Profiles for secure communications in industrial networks Communication Technology; IEC 61158-3.

-6; Fieldbus for use in industrial control systems; protocol and services; IEC 61784-1; Profile sets for continuous and discrete manufacturing relative to fieldbus use in industrial control systems; Profibus synchronous and asynchronous transmission; Profinet CBA; IEC 61784-2; Additional profiles for ISO/IEC 8802-3 based communication networks in real-time applications Transmission Technology; IEC 61158-2; Fieldbus for use in industrial control systems PhL (RS485, MBP, MBP-IS, MBP-LP, Optical Fibre, etc.); IEC 61784-1; Profile sets for continuous and discrete manufacturing relative to fieldbus use in industrial control systems; Profibus Physical Layer for synchronous and asynchronous transmission; Profinet reference to ISO/IEC 8802-3 Installation; IEC 61784-5 - IEC 61918; Installation (IEC project number still open); Integration Technologies; IEC 61804-2; Specification of FB concept and Electronic Device Description Language (EDDL); ISO15745-3; GSD: clause 6.2 of: Reference description for IEC 61158-based control systems; ISO15745-4; Reference description for ethernet-based control systems, Amendment 1: GSDML for Profinet IO.

International standards help break down trade barriers: More than 100 countries have committed to use international standards only and to withdraw opposing national specifications.

International standards open new markets: he who sets the standard, owns the market.

He who does not participate, has to depend on others, is usually late and at substantial additional costs.

International standards reduce costs: the implementation of standards means that:.

Device users can choose products from a global market that are at a minimum interoperable or even compatible.

The standardised technology has achieved a high level of consensus from experts and has remained stabled for a few years.

Device manufactures (eg PI member companies) can concentrate on their core competencies, and develop and manufacture more cost effectively.

Reuse also increases quality.

There are no customisation costs with exports ('world products') and by our participation in the standards, we ensure the interoperability of the products in multivendor systems.

Current activities and outlook.

In continuation of the abovementioned findings, there are currently a number of additional standardisation projects in the works that are influenced and driven by aspects of the Profibus and Profinet technologies.

Projects for Profibus.

The installation of Profibus including the features of Profisafe are being integrated into IEC 61918/IEC 61784-5.

The specific application profile low voltage switch gear is being integrated into IEC 32026.

EDDL extensions developed in the context of the Hart Foundation, Fieldbus Foundation and Profibus International consortia will be integrated into the 2nd edition of IEC 61804-2.

Profisafe is being integrated into IEC 61784-3.

The first committee draft was published at the end of 2004.

Test conditions for EMC measurements from Profibus PA devices are being integrated into IEC 61326-2-5.

The first committee draft was published at the end of 2004.

Projects for Profinet.

Profinet IO protocols and services have been integrated into IEC as a Publicly Available Specification (PAS).

An IEC/PAS has the status of a prestandard.

The confirmation process ended in March 2005 with the vast majority of national committees giving their approval.

Profinet IO is standardised in IEC/PAS 62411.

Its content and possible extensions will be integrated into Edition 4 of IEC 61158.

The communication profiles for the various Profinet performance classes will be described in IEC 61784-2 and the real-time ethernet principles (RTE) and measurability of RTE will be described in IEC 61784-2.

The first committee draft was published at the end of 2004.

The second CD is scheduled for October 2005.

Cyber Security (Profinet Security) will be described in ISA SP99 and IEC 61784-3.

Work has begun.

Functional Safety for Profinet (Profisafe) will be described in IEC 61784-3.

Installation Guide for Profinet is being integrated into IEC 61918/IEC 61785-5; the IEC project number is still in discussion (IEC 61918 or IEC 61784-5).

Standards ensure that technical knowledge and innovations propagate faster.

The ever shorter innovation cycles of new technologies require that standards are likewise formed just as quickly, as close to the market and real-time and standards with intensive consideration of market conditions and active cooperation between affected market participants.

Profinet International understands its obligation towards its members and will, as in the past, remain dedicated to the task in the future.