By Dave Friedlos
June 1, 2010—
SAITL Dairy Laboratory, a New Zealand company that conducts biological and chemical tests on milk samples for quality analysis, has been employing
radio frequency identification to automate the identification of batches and samples, thereby increasing the speed and accuracy of identification, minimizing manual handling, reducing errors and improving traceability.
Margaret Malloch, the Hamilton-based firm's general manager, says the laboratory receives up to 20,000 to 30,000 plastic cylindrical vials of milk from dairy factories every day. But the previous system of identification, which included bar codes and manual checking, was no longer suitable for SAITL's needs, she adds, as it was too time-consuming and prone to human error.
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The bottom of each plastic vial is fitted with a passive 13.56 MHz RFID tag.
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RFID fitted in with our planned automation of the laboratory, so we set up a project to review how best to implement the new system and the changes required," Malloch explains. "But we also needed to develop a process for writing information from bar codes to the RFID
tag for some customers, so they could still be processed via the same system."
A laboratory is a challenging environment in which to introduce RFID. Due to the samples' close proximity to one another, and the large amount of metal in many instruments, SAITL spent considerable time making sure the RFID
antenna and readers were tuned correctly, to ensure accurate and precise readings. Another challenge was the lack of a human-readable interface on the new tags. The bar-coded labels that the firm had been utilizing included human-readable text, but if the labels were replaced by a passive 13.56 MHz RFID tag attached to each vial's exterior bottom, technicians might find it difficult to locate and identify a specific sample.
"This led to a requirement for a customized large antenna and
reader software to cope with reading multiple tags in a small time frame," Malloch states.