Swedish Steelmaker Using Active RFID to Monitors Railcars

The tag stays dormant until awoken by a 125 kHz signal. Once awake, it uses the 855 MHz UHF band to transmit its ID number and the freight car's wagon number. Without volume discounts, each tag sells for roughly 60 euros, says Anders Hermanson, a sales manager for Adage.

"I don't want to reveal any company secrets," he says, "but I can say that active tags are one cornerstone of our solution as well as using magnetic fields to wake up the tags on the 125 kHz frequency."

Adage Solutions' Anders Hermanson

Swedish Steel tested some other RFID systems, but the read distances were shorter than 1 meter, which was not long enough. The company then contacted Adage, which sells active tags offering a read range of up to 10 meters.

Adage encountered a few problems while implementing the system. Hermanson explains that because the railcars are always in use, it took much longer than expected to get them into the shop so that tags could be mounted. Another challenge was Swedish Steel's requirement that a tag has a lifespan of at least 10 years. Hermanson says that his company designed the tag so that it would deactivate itself and stay that way until it received a 125 kHz wake-up signal, thus saving battery power.

"When the tag is sleeping, it is not using any power at all," he notes. "It's the same as the battery would use through self-leakage. We solved the two problems—battery life and read range—by developing our own tags and readers."

The RFID system, which cost the company about 100,000 euros, is helping Swedish Steel manage the flow of materials and plan production more efficiently. "They are counting their ROI in months," Hermanson says.