Cardinal Health Deems RFID Pilot a Success

For some time, it had been thought that UHF—the preferred choice for case- and pallet-tracking—wasn't technically sufficient for item-level tracking. UHF didn't seem to work as well as HF for tighter, smaller read ranges. That debate has been quieted (see RFID Vendors Unite to Promote UHF for Items), and Cardinal Health's results should help even more.

Case-level reads also proved successful. In fact, Cardinal Health achieved read rates on cases of between 99.4 percent and 100 percent as the distribution center received them.

During the trial, Cardinal Health read tags at several points along its supply chain. At the company's Philadelphia packaging plant, it affixed printed RFID labels, embedded with Alien Technology UHF 915 MHz EPC Gen 2 tags, to individual packages of brand-name prescription drugs. The labels were automatically applied to the individual product items and cases, and manually applied to pallets; once applied, each label was encoded with a unique Electronic Product Code (EPC). RFID interrogator antennas on packaging lines, as well as RFID portals at dock doors, read the labels as the goods moved through the packaging plant and were shipped out to a distribution center in Findlay, Ohio.

RFID interrogators at the DC read the tags as the drugs were received and shuffled through the picking and packing processes. Finally, tagged unit-level drugs mixed in totes with non-tagged items were sent to a pharmacy in the Midwest, where an RFID portal at the store's dock door scanned tags as products moved into the facility.

In the course of the pilot, Cardinal Health says it learned that trying to read tags on individual items packed in cases on pallets is very unreliable. Item-level read rates in that scenario were very low—between 7.8 percent and 14.3 percent. Kuhn says the read rates were impacted because of physics. "It has to do with the radio frequency not being able to penetrate all the contents of the pallet," she points out. Cardinal Health even had the readers send RF waves to excite the item tags on pallets for 60 continuous seconds, but still it could not achieve acceptable read rates. Especially surprising was one test of items in totes placed in a wheeled metal cart instead of in cases on a pallet. In its DC, Cardinal uses such carts to carry multiple orders packed in totes, just as it uses pallets to move multiple orders packed in cases. Each cart has three or four shelves and is able to hold a total of about 30 totes. The read rate for tagged items on carts, however, was no better than the read rate for tagged items on pallets. "We thought we'd get better reads because the items weren't packed in as tightly, so there was more air between them, and we let [interrogators] spin for 60 seconds," Kuhn says.