While the automation command “startup” may
not be as historically significant as the dots and dashes of the Morse
code “SOS” distress call, it is no less important to the day to day
operation of the factory machine that won’t go unless it gets the
instruction to begin operation.

According to industry analysts, those instructions are being
transmitted more often via wireless networks than ever before. In 2007,
industrial customers bought some 2.7 million wireless enabled factory
automation devices — predominantly rugged mobile computers, sensors and
remote I/O — a number that is projected to almost triple to 8 million
by 2013, reported Wellingborough, UK-based IMS Research in March 2009.

Much
of this growth is driven by the reduced costs and faster start up times
promised by wireless technology. If you don’t need cables then you
don’t have to pay for them or install them, but it’s not all as simple
as it sounds. Wireless adoption has had its hurdles: the most
significant of which are reliability and conservatism among the target
market.

The presence of heavy machinery or a shielded wall won’t often
disrupt the signals travelling by cable, but they can significantly
disrupt a wireless signal if the transmitters and antennae haven’t been
positioned correctly. When combined with a rise in the value placed on
dependable, detailed machine data and an “if it ain’t broke” attitude
these factors have combined to inhibit adoption.

Obviously, as IMS’ projected market growth indicates, these
inhibitors are being rapidly overcome, as the relative cost of wireless
enabled devices falls, more ruggedized wireless products hit the market
and global economic conditions make the potential cost savings more
important than ever before, prompting companies to experiment and
launch pilot projects.

“Not many people are going all in yet,” says Marty Jansons, a
spokesperson for Siemens Industry, Inc. “However we are seeing more and
more demand for wireless systems on the shop floor in a variety of
industries. Along with that we are getting a lot more people asking us
what they should be thinking about when they start looking at
wireless.”

“There are two camps when it comes to wireless: people are
either scared of it or they aren’t and it’s the second group that make
me nervous,” says Todd Preder, a business development manager with Professional Control Corporation,
a Wisconsin-based automation distributer which helps customers set up
industrial wireless networks. “The people who are more cautious
generally have more success. It’s not something that should be taken
lightly.”

In keeping with that Jansons has put together a list of six
things that customers should consider when they start thinking about
rolling out a wireless solution.

1. Have a clear idea of what you want to accomplish in both the short term and long term with the wireless network

Planning
ahead is key, stresses Jansons, adding that laying the groundwork for
future applications will save time and money in the long run. “We’ve
often seen wireless used for monitoring, warehousing, diagnostics and
I/O control applications essentially as a cable replacement system,” he
says. “But that’s only a fraction of the potential applications. We’re
already seeing it being deployed to enable seamless roaming between
indoor and outdoor for wireless VoIP communications, RFID, Automation
monitoring, wireless work tablets, PDA’s and I/P based video
surveillance.”

2. Be familiar with wireless standards. Understand the particulars of each standard and how they support wireless applications.

There is a wide variety of offerings available in the market —
Bluetooth, Zigbee, multiple flavors of 802.11, and proprietary 900 Mhz,
standards. And they are in a constant state of flux. For example, at
the beginning of September the ISA 100.11a industrial automation
standard was passed. Each has its own strengths and limitations. Are
you a discrete operation, or continuous process? If the former you
should stick with 802.11, whereas the ISA 100 standard was written with
process industries in mind. Which is right for you?

“Different technologies are available that are better suited to
different tasks,” says Preder. “For example, most office environments
rely on 802.11B or -G so we are trying to get our customers to go with
802.11A so they don’t conflict.”

3. Have a good idea of how reliable the network needs to be.

Some people believe that a wireless application needs to be as
reliable as its wired equivalent, but the vote isn’t unanimous which is
why it’s so important to know what your particular requirements are.
ARC Advisory Group research director Harry Forbes says it depends on
the application. “You can add reliability to the network later if you
need it. For a lot of applications pretty good is plenty good enough.”
This would be true in process type applications, but for most
plant-floor applications this would not be the case.

Preder agrees, but postulates that most plant floor apps are
unable to compromise reliability. “In our world most applications are
going to be I/O and for those you need to be able to depend on it the
same way you’d rely on a wired network. From an I/O perspective you are
talking about millisecond updates, as opposed to the office environment
where you send something to the printer and usually don’t care if it
takes a few minutes to get there.”

4. It's critical that every wireless solution have data security and industry standard encryption methods.

“The security word comes up again and again as an objection to
deploying a wireless solution,” says Jansons, but there’s no need for
security by obscurity. Security methodologies are there for wireless.
It’s just a matter of how deep you want to go.”

Jansons suggests a short list of industry standard wireless
encryption methods for anyone building an 802.11 network. “WEP (Wired
Equivalency Protocol), WPA (Wi-Fi Protected Access) and WPA2, all
provide at the least a base level of protection. Each encryption level
incorporates a higher degree of security thus making is more difficult
for someone to eavesdrop on a data communication conversation.

5. Understand exactly what capabilities you need from your wireless network.

“Deterministic communications, rapid roaming and environmental
ruggedization may all be factors for consideration when rolling out a
wireless network,” says Jansons. “Or they may not. You need to know
what you need before you can deploy it and achieve complete success
from your installation.”

Forbes agrees. “All of these attributes are dependent on the
application. None of these are always going to be required. Roaming is
important in in-plant set-ups, ruggedization is only required in harsh
environments while determinism is big in automotive and machine control
but not in apps that use TCP/IP. A lot of MES apps don’t need it, but
are greatly enhanced by wireless.

Another application where wireless can enhance communications
is in the area of safety. Wireless is already being implemented in
control applications dealing with safety, but, due to this being a
sensitive area, it is important to fully understand the attributes
needed.

“A lot of people are sceptical about I/O wireless, then when
you mention safety they really start to freak out. However, it is being
done successfully so it is something you may want to be ready for — at
least from a future growth perspective,” says Preder.

“Most machines with moving parts are outfitted with light
curtains or laser scanners to protect personnel working on or near the
machine and to provide better positioning accuracy,” adds Jansons.
“Using 802.11 wireless in combination with safety protocols and
failsafe PLCs can reduce cabling costs, maintenance times and shorten
downtimes.”

6. Perform some kind of wireless site assessment before making an investment.

“You want to understand your surroundings,” says Jansons. “You
may have blind spots or other areas where interference is going to
impact the network or influence the kind of technology you select.
Conducting a site survey is important as many of these issues can be
resolved before installation.”

Jansons recommends enlisting the help of a licensed
professional for this, and suggests that end users can call on a number
of entities for assistance, including systems integrators,
engineering/consulting firms or their automation vendor. However,
Forbes adds that the end user can do it themselves. “If you’re
providing coverage for an area yourself then it’s a good idea, but for
the sensing apps it’s more ad hoc testing than professional. To do
feasibility testing, most people just get a test kit from their
supplier.”

Steve Dickerson, chairman and CEO of CAMotion Inc.,
an Atlanta, GA-based provider of specialized robotic palletizers and
depalletizers to the printing and food and beverage industries, is a
huge proponent of wireless technology.

For Dickerson the to-wireless-or-not-to-wireless question comes
down to two factors. “You have to ask ‘what does it cost to put in
wires as opposed to wireless. Then you have to ask about reliability.
Stationary systems will be different, but in robotic applications
things are moving around all the time so the wires are moving around
all the time too. That movement degrades the reliability of the wires
and the connectors. In fact, these wires become the primary source of
unreliability in the whole system. On the other side, you have to be
concerned with interference. We’ve never had a problem with this, but
you have to ask the question and do a survey.”

For more information on Siemens wireless solutions, please click here.

For access to Siemens online Wireless ROI Calculator, please click here.

For more information on Wireless, please go to Automation World's Wireless page here.

For more information about wireless automation, check out www.palowireless.com.

::Design World::

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Filed Under: Factory automation, Automation components, Wireless, Networks • connectivity • fieldbuses

 

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