[ RFID ] 05. If RFID has been around so long and is so great, why aren't all companies using it?
- Many companies have invested in RFID to get the advantages it offers. These investments are usually made in closed-loop systems-that is, when a company is tracking goods that never leave its own control. That's because some existing RFID systems use proprietary technology, which means that if company A puts an RFID tag on a product, it can't be read by Company B unless they both use the same RFID system from the same vendor. Another reason is the price. If a company tracks assets within its own four walls, it can reuse the tags over and over again, which is cost-effective. But for a system to work in an open supply chain, it has to be cheap because the company that puts the tag on a case or pallet is unlikely to be able to reuse it.
[ RFID ] 06. What has prevented RFID from taking off until now?
- One issue is standards. There are well-developed standards for low- and high-frequency RFID systems, but most companies want to use UHF in the supply chain because it offers longer read range-up to 20 feet under good conditions. UHF technology is relatively new, and standards weren't established until recently. Another issue is cost. RFID readers typically cost $1,000 or more. Companies would need thousands of readers to cover all their factories, warehouses and stores. RFID tags are also fairly expensive-20 cents or more-which makes them impractical for identifying millions of items that cost only a few dollars.
[ RFID ] 07. Are any companies using RFID today?
- Yes. Thousands of companies around the world use RFID today to improve internal efficiencies. Club Car, a maker of golf carts uses RFID to improve efficiency on its production line. Paramount Farms-one of the world's largest suppliers of pistachios-uses RFID to manage its harvest more efficiently. NYK Logistics uses RFID to improve the throughput of containers at its busy Long Beach, Calif., distribution center. And many other companies are using RFID for a wide variety of applications.
[ RFID ] 08. What are some of the most common applications for RFID?
- RFID is used for everything from tracking cows and pets to triggering equipment down oil wells. It may sound trite, but the applications are limited only by people's imagination. The most common applications are payment systems (Mobil Speedpass and toll collection systems, for instance), access control and asset tracking. Increasingly, companies are looking to use RFID to track goods within their supply chain, to work in process and for other applications.
[ RFID ] 09. Where will the initial benefits of RFID technology be?
- RFID technology can deliver benefits in many areas, from tracking work in process to speeding up throughput in a warehouse. Visit RFID Journal's Case Studies section to see how companies are using the technology's potential in manufacturing and other areas. As the technology becomes standardized, it will be used more and more to track goods in the supply chain. The aim is to reduce administrative error, labor costs associated with scanning bar codes, internal theft, errors in shipping goods and overall inventory levels.
[ RFID ] 10. How does an RFID system work?
- An RFID system consists of a tag made up of a microchip with an antenna, and an interrogator or reader with an antenna. The reader sends out electromagnetic waves. The tag antenna is tuned to receive these waves. A passive RFID tag draws power from the field created by the reader and uses it to power the microchip's circuits. The chip then modulates the waves that the tag sends back to the reader, which converts the new waves into digital data.
[ RFID ] 11. What is the difference between low-, high-, and ultra-high frequencies?
- Just as your radio tunes in to different frequencies to hear different channels, RFID tags and readers have to be tuned to the same frequency to communicate. RFID systems use many different frequencies, but generally the most common are low-frequency (around 125 KHz), high-frequency (13.56 MHz) and ultra-high-frequency or UHF (860-960 MHz). Microwave (2.45 GHz) is also used in some applications. Radio waves behave differently at different frequencies, so you have to choose the right frequency for the right application.
[ RFID ] 12. How do I know which frequency is right for my application?
- Different frequencies have different characteristics that make them more useful for different applications. For instance, low-frequency tags use less power and are better able to penetrate non-metallic substances. They are ideal for scanning objects with high-water content, such as fruit, but their read range is limited to less than a foot (0.33 meter). High-frequency tags work better on objects made of metal and can work around goods with high water content. They have a maximum read range of about three feet (1 meter). UHF frequencies typically offer better range and can transfer data faster than low- and high-frequencies. But they use more power and are less likely to pass through materials. And because they tend to be more "directed," they require a clear path between the tag and reader. UHF tags might be better for scanning boxes of goods as they pass through a dock door into a warehouse. It is best to work with a knowledgeable consultant, integrator or vendor that can help you choose the right frequency for your application.
[ RFID ] 13. Do all countries use the same frequencies?
- Most countries have assigned the 125 kHz or 134 kHz area of the radio spectrum for low-frequency systems, and 13.56 MHz is used around the world for high-frequency systems. But UHF RFID systems have only been around since the mid-1990s, and countries have not agreed on a single area of the UHF spectrum for RFID. Europe uses 868 MHz for UHF, while the U.S. uses 915 MHz. Until recently, Japan did not allow any use of the UHF spectrum for RFID, but it is looking to open up the 960 MHz area for RFID. Many other devices use the UHF spectrum, so it will take years for all governments to agree on a single UHF band for RFID. Governments also regulate the power of the readers to limit interference with other devices. Some groups, such as the Global Commerce Initiative, are trying to encourage governments to agree on frequencies and output. Tag and reader makers are also trying to develop systems that can work at more than one frequency, in order to get around the problem.
[ RFID ] 14. I've heard RFID can be used with sensors. Is that true?
- Yes. Some companies are combining RFID tags with sensors that detect and record temperature, movement and even radiation. One day, the same tags used to track items moving through the supply chain may also alert staff if they are not stored at the right temperature, if meat has gone bad or if someone has injected a biological agent into food.
[ RFID ] 15. How much information can an RFID tag store?
- It depends on the vendor and the application, but typically a tag carries no more than 2KB of data-enough to store some basic information about the item it is on. Companies are now looking at using a simple "license plate" tag that contains only a 96-bit serial number. The simple tags are cheaper to manufacture and are more useful for applications where the tag will be disposed of with the product packaging.
[ RFID ] 16. What's the difference between read-only and read-write RFID tags?
- Microchips in RFID tags can be read-write, read-only or "write once, read many" (WORM). With read-write chips, you can add information to the tag or write over existing information when the tag is within range of a reader. Read-write tags usually have a serial number that can't be written over. Additional blocks of data can be used to store additional information about the items the tag is attached to (these can usually be locked to prevent overwriting of data). Read-only microchips have information stored on them during the manufacturing process. The information on such chips can never be changed. WORM tags can have a serial number written to them once, and that information cannot be overwritten later.
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