Profinet - the Profibus version of industrial Ethernet - has received a significant fillip with the announcement that four of Germany`s biggest car-makers are adopting it as the standard communications protocol for most of their automation installations. In a statement issued this month, Audi, BMW, DaimlerChrysler and Volkswagen said that they plan to adopt Profinet, and the Profisafe safety profile, with the aim of achieving a "simple and uniform link-up" of automation components.

The statement, issued by Aida - the Automation Initiative of German Domestic Automation Manufacturers - says that the car-makers will adopt Profinet subject to two criteria being met:

• that there are technical advantages in using Profinet in a specific application; and

• that there are benefits in terms of business management and operation.

Aida argues that the proliferation of communications systems with limited compatibility means that end-users are having to pay more for their automation components because component suppliers have to develop products to support a variety of protocols. According to Aida, the investment in developing products to support different protocols "generates no differences in the products, and does not promote competition".

In choosing a standard protocol, the German car-makers were looking for an Ethernet-based system that did not rely on a master-slave structure and was based on "a fixed, uniform protocol that is neutral with regard to the manufacturer and final customer". The system also had to have integrated safety capabilities.

Aida expects that adopting Profinet as the standard communications protocol for most installations will result in benefits including:

• lower costs for equipment suppliers and thus for end-users;

• reduced expenditure on engineering;

• the joint development of products for specific uses;

• lower training and maintenance costs; and

• lower hardware costs as a result of increased competition among suppliers.

At present, DaimlerChrysler`s adoption of Profinet applies to its Mercedes car group assembly plants, while Volkswagen will be using it for plants producing vehicles carrying the VW badge. Opel, as part of General Motors, is implementing Ethernet/IP, in line with GM`s policy of adopting this protocol at its plants around the world.