wilamowski-b-m-irwin-j-d-industrial-communication-systems-2011

Preambles
xix
Preamble to Part III: technologies
Stefan Mahlknecht
Institute of Computer Technology
Vienna University of Technology
Vienna, Austria
Gianluca Cena
Istituto di Elettronica e di Ingegneria dell’Informazione e delle Telecomunicazioni
Consiglio Nazionale delle Ricerche
Turin, Italy
Martin Wollschlaeger
Institute of Applied Computer Science
Dresden University of Technology
Dresden, Germany
Introduction
This part describes the technologies for industrial communications. It has been organized in seven different
groups by technology family and by application areas.
Group 3.1: Classical Fieldbus Systems
Fieldbus systems date back to the 1980s and represent the first successful attempt to bring concepts
related to local area networks to factory automation environments. Thanks to digital serial communication,
an unprecedented degree of flexibility was achieved when compared with analogue point-to-point
links, allowing remote configuration and diagnostics to be carried out easily. Moreover, noticeable savings
were made in both cabling and deployment costs because of the shared communication support.
Needless to say, these advantages made fieldbus technology more and more adoptable in industrial
plants throughout the 1990s.
One of the main drawbacks of fieldbuses is the lack, among manufacturers, of a unique, standard
solution. Instead, a large number (on the order of about 100) of different and incompatible solutions
were developed, some of which are still in use. Noticeable examples are PROFIBUS, INTERBUS,
MODBUS, as well as CAN-based solutions such as Devicenet and CANopen. In the following chapters
(Chapters 31 through 36), some of the most popular fieldbus solutions are described.
Group 3.2: Industrial Ethernet
Ethernet is currently the “de facto” standard networking solution for office automation environments.
Since its introduction in the 1970s, it has managed to keep pace with the ever-increasing bandwidth
requirements of distributed information systems and has been able to offer increased performance over
the years without losing compatibility with the original protocol and equipment.
While Ethernet was initially deemed unsuitable for use in distributed control systems, due to its random
access scheme, the extensive improvements that were made to this network made people change their
minds by the end of the 1990s. The availability of high-speed (100.Mb/s and beyond) full-duplex connections,
VLANs with traffic prioritization, and non-blocking switches made it possible to achieve increased
levels of determinism, often suitable for most factory automation systems. Solutions such as EtherNet/IP
are based on unmodified Ethernet equipment and the conventional TCP/IP communication stack.
© 2011 by Taylor and Francis Group, LLC