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RFID (Radio frequency identification) is a global term used to describe the technologies that use radio waves to identify objects at a distance.
A RFID system is made of the following elements:
When attached to an object, the “tag” , which is a chip related to a tiny antenna, is programmed with data that can be read by a reader.
The “tag” draws the necessary electric energy from the magnetic field emitted by the reader’s antenna. The tag and the reader exchange data via Hertzian waves. The reader converts the information to a computer compatible format. So the computer can record the read data or search the label ID in a database to perform another action. It can also write additional information on the label.
RFID tags come in a wide variety of shapes : self-adhesive labels, plastic discs, PVC badges, glass bulbs, plastic cylinders,…
They are classified into categories according to their energy source (passive or active) and according to their functionality (read only, write once and read write).
Passive tags draw their power from the electromagnetic waves emitted by the reader’s antenna. You already use passive RFID technology if you use the Speedpass to purchase petrol or own a car that has an antitheft immobiliser.
Active tags have a battery included in the tag and transmit actively on longer distances that can reach several kilometers. These tags are larger, more expensive and more durable. They are used for tracking trailers in yards and containers on loading docks.
Read only tags or WORM, write once read many, are pre-numbered and need a host database. When a read only tag is programmed, its data cannot be changed afterwards. Those tags can contain more information than barcode labels but those data are static and cannot be changed anymore once they are written.
The read write tags can contain more information that can be changed when it is necessary. A read/write tag is a portable database, which accompanies the product as it moves through the supply chain. The data can be modified but also permanently locked, byte-by-byte. The key feature of this system is its flexibility, a great quality for commercial and information applications, customers requirements and other variable data, which will evolve over time
There is no global public body that governs the frequencies used for RFID. In principle, every country can set its own rules for it. So each user should control that the products are compatible with the rules applied in his/her country. In short, the regulation bodies determine the frequency or the exact frequency band, the emission power and the maximum communication time between tags and readers. On the basis of frequencies, which have already been allocated and widely used (radios, televisions, army,etc), RFID got a certain amount of frequencies, classified in four groups :
Low frequency provide a short to medium read range and slower read speed.
Low frequencies (LF)
The read range with a fixed reader is up to 1.20 meter and the read speed is higher than low frequency bands. Typical applications include access control and smart cards.
High frequencies (HF)
Ultra high frequency RFID uses the 860 to 930MHz band. There are 3 frequency ranges, determined by the different areas of the world:
Ultra high frequencies (UHF)
Zone 1: primarily Europe : 865-868 MHz
Zone 2: primarily the USA : 915 MHz
Zone 3: primarily Japan and Asia: 950 MHz
Fortunately, a lot of RFID systems allow for multiple frequency readers. UHF band is usually used for supply and logistics applications. The read range can reach 13 meters.
Some RFID products also operate in microwave band at 2.45 GHz . Though microwave based RFID systems offer the highest data read rates, they are more expensive and need more energy. They are most adapted for specialized applications.
The RFID reader is responsible for capturing and processing the data contained in the RFID tag, then interfacing with the host computer that will receive the data thanks to the middleware.The tag reader communication takes place in four steps:
The middleware is the brain of the system. It manages the readers and determines the interaction with the tags. It also enables the system to make a pre-treatment of the captured data (filtering, routing, eliminating double data entries) to insert them more easily in the database of the information system.
RFID is a flexible and convenient technology, easy to use and well suited for automatic operations. It combines advantages not available with other identification technologies:
RFID does not require contact or line-of-sight between the reader and the product. It works in harsh environments, anables multiple tags to be read simultaneously and provides a high level of data integrity.
RFID also provides higher security and anables product authentication because tags can be applied discreetly and are extremely difficult to counterfeit.
RFID technology :
While many companies know they need to improve processes and efficiencies beyond current
levels, most of them do not understand how RFID technology functionalities can help them. Most assume that RFID is a technology onto itself that is expensive to implement and can lead to long down times.
RFID is actually a data collection technology quite simple to deploy. It is easily integrated into existing data collection systems and offers benefits and returns on investment beyond expectations.
If your company has already a data collection system integrated to a WMS or ERP system, and want to improve efficiencies beyond current levels, if bar codes do not contain enough information, or if you have to comply with new labelling regulations, your firm is ready for RFID.
With small and manageable process re-engineering the benefits gained in the manufacturing and distribution environment can be astounding.