There are two basic approaches to complying with RFID mandates from big retailers like Wal-Mart.

One is to apply RFID tags to cases and pallets in the warehouse. The other approach is to incorporate RFID tagging at strategic points in production, or even to track the inbound movement of goods.

The latter might be more difficult to implement, but it promises internal benefits in areas such as inventory tracking and quality control. Furthermore, it offers the opportunity to fully integrate RFID data into company processes from manufacturing through shipment.

Wells' Dairy, a LeMars, Iowa-based ice cream manufacturer, not only chose the integrated approach to RFID starting with production, but decided to use its industrial control network infrastructure to manage its RFID hardware. That decision alone eliminated the need to deploy a separate layer of RFID networking and middleware, saving that additional cost. As a result, Wells' Dairy now has both a lower cost RFID solution, but one that is fully integrated with its existing infrastructure.

"Our control infrastructure has qualities that lend itself to supporting RFID," says Brad Galles, process controls manager. "It's designed for speed, and it's designed for reliability—which are what we've come to expect on our plant floor—so it just made sense to use our control architecture to establish RFID."

This approach to RFID follows the ice cream manufacturer's overall belief that automation brings improved productivity and quality. The LeMars plant is highly automated, including an automated storage and retrieval system (HK Systems) that was recently upgraded by adding bays to the existing unit as well as seven new aisles. "Our goal is that product should not have to be touched by a person from the filler head all the way to the outbound truck," says Galles.

He continues on to say that, "From the outset, we viewed the implementation of RFID technology as a catalyst for making process changes that improve business performance. Once the data is collected, we'll use it to improve inventory tracking, automate many of our quality control and inventory processes, and simplify our data collecting processes."

Wells' Dairy is the largest family owned and managed dairy processor in the United States. Known for its Blue Bunny ice cream, yogurt and frozen treat products, the company is rolling out RFID to meet Wal-Mart's phased RFID mandate for certain products shipped to the giant retailer's North Texas region. Under the Wal-Mart program, key suppliers send tagged cases and pallets to Wal-Mart DCs. They then receive access to inventory position data as it moves through the retail DC and stores.

To meet the mandate, Wells' Dairy decided to pilot RFID on one of its high-volume lines that makes large family-size pails of ice cream. Wal-Mart considers two of these pails, shrink wrapped together, as a case.

Some of the challenges, says Galles, were that the label holding the RFID tag had to adhere to the product under freezing temperatures. In addition, the product itself tends to absorb, rather than reflect, radio signals. That required thorough testing of different tags and readers as well a label media.

"The truth is, there was very little information out there that was proven," says Galles. "And the only way to get good, accurate information was to get the equipment and test it in your own facility. As a result, we learned a lot about the technology's capabilities and drawbacks through trial and error."

In addition, there were hurdles in getting the RFID to blend with the control architecture, but those were solved through a gateway solution. The end result is that the same programmable logic controllers (PLCs) and process control network (Rockwell Automation) that manages industrial equipment also controls the RFID hardware and filters and collects RFID data. Since tags are read at multiple points in the plant, Wells' Dairy has more information it can use for quality control and inventory tracking purposes, including RFID-enabled tracking of what goes into its AS/RS. "The beauty of RFID lies in its ability to add value through increasing plant-floor visibility," says Galles.

According to Galles, the RFID gear uses the TCP/IP open socket Ethernet protocol, while the process control network uses an Ethernet variant known as Ethernet IP. A gateway module serves as the bridge between the two worlds, tying the data received from the RFID tags back into the PLCs for filtering and data handling. From there, the data goes to a database where it can be shared with the rest of the enterprise.

"Our whole plant is run off of our industrial control system," Galles says. "It just made sense that since the RFID tagging was going to tie into the different piece of equipment, that the system controlling our equipment also control our RFID activity."

The RFID tagging and reading of the pails occurs at multiple locations. It begins on the production line right after two pails are wrapped together to form a case. It ends several steps later at a pallet wrapping station positioned where pallets enter the automated storage system, which stores full pallets at below freezing temperature.

"We refined the process with our largest line of ice cream, and I'm glad we did, because we now don't anticipate any major issues during the rollout," says Galles. "If the pilot had been smaller or set up remotely, we would not have identified many problems—like having tags fall off in the quick—freeze portion of the process-that we've now solved."

Each RFID tag holds an individual serial number for each case, and the tag also is linked to a database that hold the production attributes of each ice cream bucket—such as the time it was made, the batch number, and which production line it was made on. From this, Wells' Dairy knows precisely what time every tag was applied and from what batch the pallet was produced.

But the internal efficiencies do not stop there. Others include: automatic generation of pallet tags based on system knowledge of serialized cases; a more precise ability to recall or hold a product; and simpler pallet tagging, because the RFID tags only need to be on the correct side of the pallet, rather than a much smaller area with conventional bar codes, to ensure correct reads. Also, once RFID is rolled out across product lines, the RFID will be able to automate some inventory counting tasks.

In the future, Wells' Dairy hopes RFID will help automate additional processes, and even track incoming raw materials. Already, Galles concludes, "RFID gives us a new level of visibility. It will provide a better understanding of what we shipped, where it's at, and what gets to our customer."