08-16-2017, 09:20 PM
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RFID
INTRODUCTION
RFID is an acronym for Radio Frequency Identification. RFID is one member in the family of Automatic Identification and Data Capture (AIDC) technologies and is a fast and reliable means of identifying just about any material object.
Primarily, the two main components involved in a Radio Frequency Identification system are the Transponder and the Interrogator. Communication between the RFID reader and tags occurs wirelessly and generally does not require a line of sight between the devices.
An RFID reader typically contains a module (transmitter and receiver), a control unit and a coupling element. The reader has three main functions: energizing, demodulating and decoding. In addition, readers can be fitted with an additional interface that converts the radio waves returned from the RFID tag into a form that can then be passed on to another system, like a computer or any programmable logic controller. Anti-Collision algorithms permit the simultaneous reading of large numbers of tagged objects, while ensuring that each tag is read only once.
RFID is a sight less identification system. It is the combination of Radio Frequency and the Microchip technologies. RFID transmits the identity of an object as a unique serial number. This identity is stored in the tag chips and can be retrieved by the Readers. The components of RFID are
Tag
Interrogator
TAG:
Tag, also called transponder is a small device which contains a microchip. The chip is used to store the data. The tag can be programmed with specific items of information, such as an ID or serial number or a user data. The tag identifies itself by transmitting signals to the Interrogator.
There are two types of Tags namely,
Active Tag
Passive Tag
Semi Passive Tag
ACTIVE TAG:
Transmits signals from the microchip circuit through the power obtained from an internal battery
High Signal range
Used on large assets, such as cargo containers, rail cars, and large reusable containers
Costlier and Larger in Size.
PASSIVE TAG:
Contains no power source
Obtains power from the Interrogator
Low Signal range
Cheaper and Smaller than active tags
SEMI-PASSIVE TAG:
Semi-passive RFID uses an internal power source to monitor environmental conditions, but requires RF energy transferred from the Interrogator similar to passive tags to power a tag response.
Semi-passive RFID tags use a process to generate a tag response similar to that of passive tags.
Semi-passive tags differ from passive in that semi passive tags possess an internal power source for the tag's circuitry which allows the tag to complete other functions such as monitoring of environmental conditions and which may extend the tag signal range.