The EN50170 Standard for a European Fieldbus

With the advent of newer and newer products on the industrial automation markets, fieldbuses are becoming a reality and their adoption is significantly increasing in a large number of different application fields. Unfortunately the long delays experienced in the definition of a worldwide international fieldbus standard by IEC has contributed to make the fieldbus situation unstable and confused at least from the points of view of the users and system integrators. This important fact, and the need to protect the significant investments made by the European industry to gain the leadership in fieldbus technologies, convinced CENELEC in 1993 to promote the definition of a European standard concerning field communications. The new standard, known as EN50170, was formally approved in March 1996 and was based on existing and well-established technical solutions. The attention of this paper is focused on the EN50170 specifications. As well as a discussion of the reasons and the criteria considered in defining the standard, the paper contains a brief introduction to the technical characteristics of the three different solutions contained in the EN50170 documents and referred to as volume 1, 2, and 3 respectively.