"RFID is a sensing technology," says Alex Stuebler, business manager, Siemens Energy & Automation Inc. (Norcross, GA), which supplies readers, antennas, tags, printers, and software. The company recently introduced the Simatic RF600 family of RFID products for production, warehousing, and retail store applications, and offers RFID consulting services via its Siemens Business Solutions Group.

RFID makes it possible for manufacturers to automatically sense a part or asset's proximity, and gather information about its location. Collecting this data at critical points in the plant improves visibility within the four walls, and can serve as the basis for quality assurance and product genealogy documentation.

On the asset management side, RFID can help improve the maintenance and repair process and minimize equipment downtime. Because RFID collects information without human intervention, it also boosts labor productivity by automating manual data collection tasks.

RFID tags used in factory floor applications are typically passive rather than active, or self-powered, and use a variety of frequencies. Having read/write capability makes it possible to add information to a tag at each step of the process. Read-only tags and tags that read/write once simply serve as a "license plate" linking to data in a manufacturing execution or other enterprise system. Manufacturers use battery-powered active tags when they need to store large amounts of data or require a long read range.

DEPLOYMENT CONSIDERATIONS

When deploying RFID, it's essential to consider the meaningful information the technology provides, such as support for lean manufacturing or Six Sigma programs.

"Return on investment is associated with the business process changes RFID enables," says Vivek Bapat, director of marketing, Rockwell Automation Inc., which offers hardware, engineering, and business services as well as the resources of its RFID pilot lab in Milwaukee. When implementing a factory floor RFID system, it's essential to determine "how, where, and what type of information will be added to the tag," Bapat says.

Not surprisingly, practical considerations abound. Read distance -- or how close the tag must be for the reader to scan it -- is one major consideration. Other basic questions manufacturers should answer include: How much data must be communicated to and from the tag? What environment will the tag encounter? Will it be submerged in paint, baked in an oven, surrounded by metal?

"Factory equipment can cause interference," warns Greg Edds, manager of global operations at Hewlett-Packard (Palo Alto, CA), an RFID user. "A lot of equipment today emits high-frequency energy. It's easy to map process flow, but testing is needed to understand how tags and readers interact with various systems." In addition, RFID on the factory floor inevitably requires some capacity for filtering data. Manufacturers often accomplish this via middleware, but data filtering may also be performed at the device or network level. RFID information typically streams into the programmable logic controller, which may filter the data before passing it on to higher software layers such as manufacturing execution and enterprise resource planning systems.

Rockwell, for example, builds a filtering capability into its Allen-Bradley ControlLogix controllers via a product extension called EWEB. The EWEB module also transmits data from the controller to RFID printers and readers. This bi-directional communication and data filtering helps eliminate the need to install new hardware/ software.