Plant managers are adding a powerful
tool in their efforts to gather more data
and keep equipment running smoothly—
wireless networking. It lets them
locate sensors anywhere, move equipment
without routing wires, and perform tasks that
would have been difficult or even impossible.
A range of wireless technologies is seeing
increased usage as engineers gain confidence
that they will work flawlessly in harsh industrial
networks. In fact, acceptance of these
technologies is following the path experienced
by Ethernet.
After a period of skepticism, clever designers
came up with techniques that proved
effective, bringing increased acceptance.
Now it’s growing rapidly, albeit from a small
base. IMS Research forecasts unit shipment
growth of nearly 30% through 2010.
System integrators can choose from a
number of different options. Wi-Fi provides
compatibility with Ethernet backbones. Wireless
Hart leverages the popular Hart protocol.
Emerging standards, including ISA SP-100.11
and ZigBee, are challenging a number of proprietary
mesh technologies.
Vendors representing these technologies
have banded together within the Wireless
Industrial Networking Alliance. This consortium
includes suppliers as well as equipment
makers like Honeywell and Emerson.
Many protocols are getting more play as
engineers use them to install sensors and
other gear in spots that would be difficult to
wire. Sometimes those installations will be
temporary, giving managers a way to zero
in on a piece of equipment, adding sensors
and diagnostic equipment to gather data for
a short time. These systems can be used to
rectify problems, then move to other areas to
facilitate further performance enhancements.
Wireless links are also seeing use in permanent
installations. Sensors can be added in
hard-to-reach spots, letting managers perform
tasks like monitoring vibration to determine
when equipment should be shut down for
repairs before failures arise. They can also be
used for ancillary tasks like the addition of
security sensors, which can boost productivity
by preventing sabotage or theft.
WHAT'S IN COMMON
The common thread for these applications
is that wireless extends networks into hardto-
reach areas. “The next wave of adoption
will be to the last foot, putting sensors here
and there to collect data,” says Paul Daugherty,
wireless products manager for GE Fanuc.
Though wireless networks make it simpler
to implement equipment in these locations,
such installations can’t be done without
planning. Industrial environments are
extremely noisy environments that are constantly
changing as equipment is moved and
changed. Maintaining signal integrity is still
a challenge.
“There’s no question that reliability is the
number one thing,” says Cliff Whitehead,
strategic applications manager at Rockwell
Automation. “You need to spend more time
planning than when you install a wired network.
You need to understand that the factory
is dynamic.”
Suppliers are attempting to simplify these
installations by providing complete systems.
For example, Phoenix Contact’s RAD-SYSNEMA4X-
900 includes a 24-V dc power
supply, a uninterruptible power-supply (UPS)
system, surge protection, and an antenna
adapter. The radio-ready package, housed in
a NEMA 4X enclosure, simplifies the installation
of industrial wireless radio modems and
small remote-thermal-unit (RTU) devices.