Image Processing Reference
In-Depth Information
TABLE .
Comparison of Key WSN Standards in Industrial Automation
ZigBee
WirelessHART
ISA.a
Availability
June , 
September , 
Draft
PHY layer
IEEE ..
IEEE ..
IEEE ..
Standard specifies
Layers  and 
Layers -, and 
Layers -, and 
Frequency
 MHz
. GHz
. GHz
 MHz
. GHz
RF transmission
DSSS
FHSS
FHSS
. GHz:
. GHz:
. GHz:
 channels
 channels
 channels
/:
+
 channels
Media access
CSMA/CA optional GTS
TDMA, optional CSMA/CA
shared slots within TDMA
slot
TDMA
Network topology
Mesh, star, hybrid
Mesh, star, (hybrid possible,
but not specified)
Mesh, star, hybrid
Bit rate
 kbps
 kbps
 kbps
Security
Optional: symmetric keys,
AES- encryption
Symmetric keys, AES-
encryption
Symmetric keys, AES-
encryption. Optional use of
asymmetric keys
Coexistence
CSMA/CA
Optional channel black
listing, optional CCA,
settable transmission power
levels
Optional channel black channel
assessment (CCA), settable
transmission power levels
Source: Lennvall, T., Svensson, S., and Hekland, F., in th IEEE International Workshop on Factory Communication Systems
(WFCS ) , May , , Dresden, Germany. With permission.
27.5.1 Standards Landscape
Table . provides an overview of the three main WSN standards targeting the industrial (pro-
cess) automation market. Most fieldbus organizations refer to either of these standards when they
think about how to integrate WSN into their wired bus infrastructure. In addition, there are pro-
prietary solutions out on the market, which could be considered de facto standards in certain niche
applications.
Below follows some more details on the background of these standards. For a more technical
description of the underlying technologies that are employed, see Section ...
27.5.1.1 ZigBee
One of the best-known standards is the ZigBee standard; a low-power, -cost, and -data rate wire-
less specification, which targets home appliances, toys, industrial applications, building automation,
andthelike.heZigBeestandardisdeveloped,managed,andpromotedbytheZigBeeAlliance[].
hescopeorfocusoftheZigBeeAllianceisondeiningthenetwork,security,andapplicationsot-
ware layers, providing interoperability and conformance testing specifications, and promoting the
ZigBee brand.
27.5.1.2 WirelessHART
WirelessHART is the only industrial WSN standard currently available. It was released during
September  [], and is a secure and reliable wireless technology for industrial applications
ranging from class  to  (see Table .), i.e., from control to process measurement/monitoring. Wire-
lessHART extends the well-known HART standard into the wireless domain, enabling new market
areas for the large number of HART users. HART communication [] is a bidirectional industrial
field communication protocol used to communicate between intelligent field instruments and host
systems. HART is the global standard for smart process instrumentation and the majority, more than
 million of smart field devices installed in plants worldwide, are HART-enabled.
 
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