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

xx
Preambles
In order to cater to highly demanding control applications with tight timing constraints, such as
motion control, a number of modifications have been proposed in the past few years that are aimed at
further enhancing the real-time behavior of Ethernet. While relying on the same transceivers, frame format,
and access scheme as the original protocol, changes were added to the original Ethernet hardware
or communication stack. This is the case, for example, of EtherCAT, Ethernet Powerlink, PROFINET
IRT, and so on. The following chapters (Chapters 37 through 40) focus on some of these solutions.
Group 3.3: Building Automation Networks
Modern building automation networks are based on distributed networks where network topologies are
flexible enough to reflect the building structure. They are primarily based on wired technologies although
wireless extensions also exist. Installation and maintenance are key issues, as large networks may comprise
thousands of nodes. Two widely adopted technologies, namely, LonWorks and KNX, have been on the market
for many years and occupy different market segments. LonWokrs, due to its flexibility, is applied more in
large buildings and industries, while KNX is used more in private homes. In many large buildings, a heterogeneous
network with LonWorks-, KNX-, and IP-based networks are implemented. The following chapters
(Chapters 41 through 43) present the main building automation networks standardized under ISO.
Group 3.4: automotive Networks
Automotive networks have the same advantages that fieldbuses bring to industrial automation environments,
in particular for in-vehicle control systems such as powertrain, body electronics, or infotainment.
There is no doubt that the most popular solution so far has been the controller area network
(CAN) protocol introduced by Bosch in the mid-1980s in order to reduce cable clutter in cars and trucks.
Despite being perfectly suitable for most of today’s vehicles, CAN has some drawbacks that will likely
rule it out for next-generation automotive systems. In particular, when taking steer-by-wire systems
into account, a much higher degree of determinism, performance, and, mostly, fault tolerance has to be
ensured. This has led to the introduction of the time-triggered architecture (TTA) and, in particular, the
TTP/C protocol. In order to reduce design and production costs, high flexibility is required as well. To
this extent, the FlexRay protocol has been defined, which combines the dependability and determinism
of TTP/C with the ability to carry out data exchanges on demand, through a flexible time division multiple
access scheme. The chapters that follow (Chapters 44 and 45) describe the basic principles behind
the new high-performance solutions as well as low-cost in-vehicle networks such as LIN.
Group 3.5: Safety
Safety is one of the most important requirements in industrial applications. The guaranteed transmission
of secured data in a reliable time frame, order, integrity, and sequence is an evident task in systems
where man and equipment are at risk of being harmed. Thus, safety integrity levels (SIL) have been
defined that must be met by technical systems (Chapters 46 and 47). Typically, safety-related functions
are not originally embedded in industrial communication systems. In order to meet the required criteria,
add-ons to existing protocols and systems have been defined. Thus, interoperability with existing
protocols and applications can be ensured.
Group 3.6: Wireless Networks
Wireless networks have experienced tremendous growth in the last decade, driven by mobile phones and
the computer industry. Most of us are familiar with the widely used technologies in consumer products,
such as GSM/3G, WLAN, and Bluetooth. In contrast, wireless automation networks or sensor networks
are still a topic of research, and products are either available only in certain segments or are slowly entering
© 2011 by Taylor and Francis Group, LLC