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The Use of Radio Frequency Identification as a Replacement for Traditional Barcoding
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Technology
Barcoding
Traditionally, retailers, manufacturers and logistics have used barcoding as a quick and easy way to track inventory. Barcoding uses several symbologies (digital languages) to digitally encode data so that it may be read optically by a computer-based scanner. Barcoding has distinct advantages over keyboard data entry in terms of data accuracy, data transfer speed and versatility.
The disadvantage of barcoding is that each item (unit, batch, truck, etc) must be scanned manually. There have been several attempts to automate barcode scanning with mixed results. Barcodes can only store a limited amount of information. Once a tag is printed, the information contained in that tag cannot be changed. The tag must be changed when information is modified. Degradation of barcode tags is a big issue as well. A dirty or damaged tag cannot be read. And protecting these tags in harsh environments is a challenge.
Radio Frequency Identification (RFID)
RFID technology has been around since the early 1920's. It was developed at MIT as a way for robots to "talk" to one another. The technology was used extensively by the British in WWII as a way to track planes and other vehicles.
RFID systems have three basic components: an antenna or coil, a transceiver (with decoder), and a transponder (RF tag). Data is generated and stored by a primary host computer or PLC, similar to bar code systems. The antenna generates a magnetic field which activates the magnetic tag and enables communication between the tag and the transponder. Often the antenna and the transceiver are packaged together as a reader. The range of the system can be more than 100 ft depending on the type of transponder tag used and the operating frequency. RFID systems can be categorized as either low frequency or high-frequency. Low-frequency (30 KHz to 500 KHz) systems have short reading ranges and lower system costs. High-frequency (850 MHz to 950 MHz and 2.4 GHz to 2.5 GHz) systems have higher ranges and much higher scanning speeds, but at a much greater cost.
The RF tag itself houses an integrated circuit which stores the information. Tags can be either active or passive. Active tags contain a power supply. They have read-write capabilities, greater memory capacity and a much greater operating range than passive tags. They are also much bulkier and much more expensive than passive tags and their lifespan is limited. Passive tags are generally read-only (similar to bar codes). They have lower operating ranges and lower memory storage capacity. They are, however, much less expensive, more durable and smaller than active tags. Both active and passive tags can be made in a virtually unlimited number of configurations. They can be as small as a flake of pepper, as thin as a credit card and can even be fabricated as part of the product itself (i.e. a screw or bolt).
When an RFID tag passes within the operating range of the reader, it detects the reader's activation signal. The reader decodes the data encoded in the tag's integrated circuit and the data is passed to the host computer for processing. For an active system, the RF tag can actually contribute information to the process (e.g. delivery instructions, machinery instructions, inventory level instructions, etc.).
The significant advantage of RFID systems is that they do not require direct contact or line-of-sight to operate properly. Tags can be read in all types of environments such as snow, fog, ice, paint, dirt, and other harsh conditions. RFID tags can also be read very quickly, in most cases responding in less than 100 milliseconds. The new generation of readers coming to the market have the ability to read multiple tags simultaneously. Thus an entire area of inventory can be scanned at once instead of scanning each unit individually.
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Outdoor Gate Antenna
Texas Instruments
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The most significant advantage of RFID systems is the capability of enabling electronic product surveillance. In contrast to the traditional point-to-point system, inventory can be tracked at any and all points throughout the supply chain. Instead of creating a point-to-point network for communicating supply and demand, we can create a network of products can communicate with machines, products can communicate with other products, shelves can track their own inventory and signal for replenishment when necessary. The need for human interaction in supply chain management is all but eliminated.
RFID systems have been around since the late 60's. Recent technology advancements (specifically advances in automated integrated circuit assembly) have brought prices down to a level that is reasonable to enhance the application base. The industry is currently moving in the direction of conductive inks for printable antennae and tags. With advances in these type of technologies, RFID tags may soon reach the once-unachieveable 5-10 cent price range.
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