Automatic identification and data collection (AIDC) technologies and applications are evolving so rapidly that...
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it's hard to know where to start. From 2D barcodes to item-level radio frequency identification (RFID) tags and wireless sensor networks, the technology choices alone are confusing enough without factoring business needs and physical constraints into the equation. But experts can recommend a few AIDC best practices for designing systems that take full advantage of the technology without breaking the bank.
“One isn’t replacing the other—they’re doing different things,” said Kimberly Knickle, practice director for emerging agenda, sustainability and the asset-oriented value chain (AOVC) at Framingham, Mass.-based IDC Manufacturing Insights. Knickle gives the example of a manufacturer that has a large yard at its facility and uses RFID for yard management. Barcodes would not be useful in such a big space, and the RFID readers would need to be connected using Wi-Fi since the target area is outside, Knickle explained.
“People add RFID and other sensor technology like barcodes not to replace what they have, but to do something new that the existing technology can’t do,” Knickle said. “It’s not unusual to find multiple technologies in use at one company.”
Combining RFID, Barcodes, Wi-Fi in Manufacturing
RFID hasn’t replaced barcodes in part because of its cost, according to Knickle. Barcode labels are relatively inexpensive to make, but RFID chips are more complex and therefore more expensive. There’s also the matter of whether a technology replacement is even necessary.
“If you have a technology in place that works, like barcodes, why replace it?” said Knickle. “Often you have two labels—one that’s your barcode and one that’s your RFID. You might put the barcode on the box and RFID on the multiple items in the box to give you a more granular look into what’s in the box and what inventory will need to be replaced. RFID can also be used on more expensive items that are subject to theft.”
Byron Blackburn, principal at Woodstock, Ga.-based consulting firm Blackburn Global, cautions against looking at the wireless AIDC technologies from an either-or angle. “They’re not competing technologies, they’re complementing technologies,” he said. “Barcode can be standalone, but if you don’t have a back-end system that can convert that to meaningful data, it’s useless.
“None of them are very valuable as a standalone. Barcodes are less effective without Wi-Fi, but RFID is much more efficiently managed on its own channel, so you have no interference,” Blackburn said.
The barcode vs. RFID choice often comes down to security issues, said Bert Moore, director of technical communications and media relations at the Association for Automatic Identification and Mobility (AIM), based in Cranberry Township, Pa.
Take two-dimensional (2-D) barcodes, which Moore said were already gaining among manufacturers and retailers before the popularity of smartphones turned the now-ubiquitous, checkerboard-like squares into social media marketing tools. “The drawback to them is they can be easily counterfeited,” he said.
For similar reasons, companies are increasingly using RFID tags called e-seals (electronic seals) to secure trucks and shipping containers in an effort to ensure the authenticity of the contents, including their barcodes, he said. Manufacturers must also consider whether the RFID tag should be attached to sensors that measure temperature, air pressure or physical stress. The sensors can help avoid spoilage and damage from environmental changes and make it easier to monitor and repair products under warranty.
Manufacturers using multiple wireless technologies might also find that they’ve stretched their IT resources past the limits, according to Blackburn. “There are people who do RFID on a Wi-Fi network, but that burdens the network with RFID tags that are ‘talking’ too much,” he said. “Ten years ago, RFID was a very good idea. But RFID tends to just cannibalize the Wi-Fi network.”
Understanding RTLS technology choices
Manufacturers who want to use AIDC for a real-time location system (RTLS) will likewise need a mix of technologies to ensure coverage across geographic locations and varying environments. “It’s really a matter of clearly defining objectives,” Moore said. “How much accuracy do you need? Are there going to be obstructions?”
For example, accuracy within several feet rather than inches might be adequate for finding large items in relatively uncluttered sites. “Once you’re within 10 feet of it, it should be pretty obvious that it’s there,” said Moore. In contrast, cluttered spaces are typically more expensive to outfit because they have more obstructions that block radio raves, which necessitates more transmitters. If the obstructions contain metal or water—even paper has a surprising amount of the latter—then the network should be based on lower frequencies, which do a better job of penetrating, he said.
Ultra-wideband networks are a common choice for RTLSes in such environments, but the slower data rates work best for detecting slower-moving assets, he said. “RTLS is usually for things that have moved, but are not moving now,” Moore said. One common exception: forklifts in warehouses. A higher-data-rate RTLS can spot their locations fast enough to prevent collisions.
Companies must also figure out how often the RTLS sensors—typically active RFID tags, which can send data to transmitters rather than just receiving it like passive RFID tags—must signal their location. “Do you want one that beacons all the time, or do you want one that only responds when it’s queried? Obviously, that will affect battery life,” he said.
Fortunately, people-related issues, including training and ongoing use, are minimal. “RTLS is designed to be an automatic data-capture technology,” Moore said. “Once it’s set up properly, it should take care of itself. A majority of the work goes into designing and implementing the system.”
Still, RTLS is also used to track the locations of people, typically when there is an emergency, such as a mine explosion, but also to monitor their movements and analyze their performance. “If a person is not moving for a few minutes, do you have a concern that they are in trouble?” asked Ralph Rio, research director at ARC Advisory Group, based in Dedham, Mass. Instead, they could be doing something innocuous, such as taking a lunch break. “There are concerns about privacy, and those need to be dealt with.” Rio said some companies solve the problem by giving employees the ability to turn off their sensors. “That’s a way to give someone autonomy.”
Mobile Devices and the Future of AIDC
Personal mobile devices, now more available than ever, can help manage this plethora of AIDC technologies, Blackburn said. “To find a lost item, I can go to my smartphone, log into the RFID channel, and locate it. Same thing with barcodes. It’s very simple, no more than a keyboard entry converted into a data stream that can be scanned. You used to have to have a computer and scanner for each person, but Wi-Fi makes this easier. Now each person has a smartphone that can scan.”
Another smartphone capability—the near field communication (NFC) transmissions used for “electronic wallet” purchases in Europe and Asia—could lead to new AIDC applications for businesses, said Moore. With NFC, each smartphone is effectively a short-distance RFID reader and tag. “It’s one of the things that people should start thinking about. Some of these [applications] come completely out of the blue. It just makes tremendous sense to be aware of all the technology.”