Setup: Characterization and test of industrial RFID
In the industrial environment, RFID helps reduce the cost in supply chain management tracking tools and goods used in the manufacturing process, says Christian Gindorf, National Instruments business development manager for ATE (automated test equipment). Large numbers of units can be quickly identified by reading the ID wirelessly, without a direct line of sight, he says.
Complicated environmental challenges for RFID engineers include harsh environments and consideration of material upon which the tags are mounted. Metals reflect signals, while liquids change the resonant frequencies due to absorption, Gindorf says.
Global economies of scale can increase efficiencies and further reduce costs if the system can be widely used, but manufacturers must obey different RFID regulations, Gindorf says. Europe uses frequencies around 868 MHz, the U.S. uses 915 MHz, Japan uses 950 MHz, and the world uses 13.56 MHz in RFID systems.
For manufacturers of RFID components and systems, it is important to characterize operation of tags in various environments and operating frequencies. "A traditional approach uses bench-top instruments connected to a PC via GPIB [general purpose interface bus, IEEE-488] or Ethernet. An RF generator sends a signal to the unit under test and an RF analyzer receives and decodes the answer from the tag," Gindorf says. To characterize a tag, vary the frequencies and transmission power. "This requires several thousand measurements and leads to long test times since GPIB and LAN [local area network] have low throughput and high latency times. A better approach is a system where the PC and RF-instruments are integrated and use a high-speed bus such as PCI or PCI Express. This type of system can easily reduce test time by a factor of ten," he maintains. NI advocates use of programmable FPGA (field programmable gate array) hardware because of power and flexibility. The company's "PCI-5640R IF-RIO enables a user to create a software defined RFID reader where the operating frequencies and the power levels can be varied based on every aspect of the protocol."
—Edited by Mark T. Hoske , Control Engineering editor in chief