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

53
WirelessHART,
ISA100.11a, and OCARI
Tuan Dang
EDF Research and
Development
Emiliano Sisinni
University of Brescia
53.1 Introduction..................................................................................... 53-1
53.2 WirelessHART................................................................................. 53-2
The WirelessHART Physical Layer. •. The WirelessHART Data
Link Layer. •. Time Keeping. •. The WirelessHART Network Layer
and Topologies. •. The WirelessHART Upper Layers
53.3 ISA100.11a........................................................................................53-8
The ISA100.11a Physical Layer. •. The ISA100.11a Data Link
Layer. •. Time Keeping. •. The ISA100.11a Network Layer
and Topologies. •. The ISA100.11a Upper Layers
53.4 OCARI............................................................................................ 53-10
Physical Layer. •. MAC Layer. •. Network Layer
and Topologies. •. Application Layer
53.5 Coexistence of the Three Protocols............................................ 53-13
53.6 Example of Platform Providers................................................... 53-15
53.7 Conclusions.................................................................................... 53-16
References.................................................................................................. 53-16
53.1 Introduction
The world of industrial communications shows increasing interest toward wireless fieldbuses, i.e., the
use of wireless communications to interconnect devices at field level sensors; actuators; instruments;
controllers; and so on [W08,FFM07]. In particular, the advent of hybrid wired/wireless networks promises
to greatly improve efficiency and scalability. However, the success of this kind of solutions will
depend on the standardization process that ensures multivendor compatibility and interoperability.
A big step toward the development of a truly open and standard solution has been done thanks to
the introduction of the IEEE 802.15.4 specifications [I06]. In particular, this standard body created a
physical layer (PHY) description that maintains good performances in presence of noise and interferences,
but it is simply enough to allow system designer to produce low power consumption and lowcost
devices. In fact, a wireless sensor for industrial applications must work in a noisy environment
on one hand and must ensure an overall device lifespan and cost comparable with traditional wired
systems, on the other one. The adoption of a direct sequence spread spectrum (DSSS) strategy mitigates
interferences and offset quadrature phase shift keying with half-sine shaping (OQPSK-HSS) modulation
ensures good spectral occupancy. However, the adoption of carrier sense multiple access with collision
avoidance (CSMA/CA) at the medium access control (MAC) level poses severe limits on the respect of
real-time deadlines, a typical requirement of industrial applications.
In order to overcome such limitations, a lot of solutions employing radios compliant with IEEE
802.15.4-PHY but using time division multiple access (TDMA) protocol at the MAC layer have appeared
53-1
© 2011 by Taylor and Francis Group, LLC