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 ...