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Introduction

RFID stands for Radio Frequency Identification. It is an automatic identification technology to identify objects by using invisible radio waves. Instead of optically scanning bar codes on a label, RFID uses radio waves to capture data from tags. One of key characteristics of RFID is that it does not require the tag to be seen to read its stored data. This means that a tag can be placed either inside or outside. To accomplish this, two components are essential, reader and tag. A transponder has a microchip that contains information uniquely identified itself, such as a serial number. A reader sends out a radio signal that wakes a tag from its dormant state. The transponder then responds with a coded radio signal to uniquely identify itself. The reader converts the radio waves returned from the tag into a form that can be passed on to computer that can further utilize the information.

The RFID system contains the following component:

  1. RFID Transponder
    A RFID Transponder, contains three kinds of transponder, Proximity smart card (contactless smart card), RFID Tag and Smart Label, is made up of a microchip with a coiled antenna and is used to identify objects, which can be uniquely programmed with information about the objects. RFID transponders can be encased in hardened plastic coatings making them extremely durable and able to be tracked through harsh production processes. They can be read through grease, dirt, and paint. RFID transponders can store large amounts of data. High-end RFID transponders can contain up to one megabyte of memory (one million characters), although most tags only contain a small fraction of this memory, perhaps as little as 64 bits.
    Data within a tag may provide any level of identification for an item during manufacture, in-transit, in-storage, or in-use. With additional data, the tag may support applications that need item-specific information. For example, shipment consignee or destination ports can be readily accessed upon reading the tag.
    Some RFID transponders are able to support read/write operations, enabling real-time information updates as a tagged item moves through the supply chain.
  2. Readers (handheld or stationary)
    A reader, also called interrogator, is comprised of a transmitter, receiver, control module and a transceiver. The transceiver acts as a communication function to link to a controlling computer or PLC. A reader should have an attached antenna, which is used to transmit and receive the RF signal. Each reader is accompanied with software that allows the user to read and program tags. Serial (RS232 or RS422/485) or Ethernet are the typical communications methods, though others are available.
  3. A data handling and processing system.

Information is sent to and read from RFID transponders by a reader using radio waves. In passive systems, which are the most common, The reader sends out electromagnetic waves that form a magnetic field when they "couple" with the antenna on the RFID transponder. A passive RFID transponder draws power from this magnetic field and uses it to power the microchip』s circuits. The chip then modulates the waves that the tag sends back to the reader and the reader converts the new waves into digital data. Then the digital data can be sent to a controlling computer for processing and management.

In active systems, a battery in the tag is used to boost the effective operating range of the tag and to offer additional features over passive tags, such as temperature sensing. Data collected from tags is then passed through familiar communication interfaces (cable or wireless) to host computer systems in the same manner that data scanned from bar code labels is captured and passed to computer systems for interpretation, storage, and action.

RFID creates an automatic way to collect information about a product, place, time or transaction quickly, easily and without human error. It provides a non-contact data link, without need for line of sight, for example articles inside a cardboard box, or concerns about harsh or dirty environments that restrict other auto ID technologies such as bar codes. In addition, RFID is more than just an ID code, it can be used as a data carrier, with information being written and updated to the tag on the fly. Genesis has the programming ability to install RFID readers and tags into your material handling system and integrate them with your PC or PLC network. Implementation of RFID will allow the improvement of data quality, items management, asset visibility, and maintenance of materiel. Further, the use of RFID in the supply chain has the potential to provide real benefits in inventory management, asset visibility, and interoperability in an end-to-end integrated environment. RFID encapsulates the data accuracy advantages inherent in all types of automatic identification technology. Additionally, RFID is a totally non-intrusive methodology for data capture (requires no human intervention), is non-line of sight technology, and is a technology that may possess both read and write options within the same equipment item.

Active RFID Tag uses an internal power source, such as a battery, within the tag to continuously power the tag and its RF communication circuitry. Active RFID tag allows extremely low-level RF signals to be received by the tag (since the reader/interrogator does not power the tag), and the tag can generate high-level signals back to the reader/interrogator. Active RFID transponders are continuously powered, whether in the reader/interrogator field or not, and are normally used when a longer tag read distance is desired.

Passive RFID Tag relies on RF energy transferred from the reader/interrogator to the tag to power the tag. Passive RFID transponders reflect energy from the reader/interrogator or receive and temporarily store a small amount of energy from the reader/interrogator signal in order to generate the tag response. Passive RFID tag requires strong RF signals from the reader/interrogator, and the RF signal strength returned from the tag is constrained to very low levels by the limited energy. Passive RFID transponders are best used when the tag and interrogator will be close to one another.

Semi-passive RFID Tag uses an internal power source to monitor environmental conditions, but requires RF energy transferred from the reader/interrogator similar to passive tags to power a tag response. Semi-passive RFID transponders use a process to generate a tag response similar to that of passive tags. Semi-passive tags differ from passive tag in that semi passive tags possess an internal power source (battery) for the tag's circuitry which allows the tag to complete other functions such as monitoring of environmental conditions (temperature, shock) and which may extend the tag signal range.

Transponder

RFID transponders consist of an integrated circuit attached to an antenna-typically a small coil of wires-plus some protective packaging as determined by the application requirements. RFID transponders can come in many forms and sizes. Some can be as small as a grain of rice. There are basically two types of RFID transponders, active and passive.

Active tags have a battery, which is used to run the microchip's circuitry and to broadcast a signal to a reader have power on the chip that are generally used for tracking high-value goods that need to be scanned over long ranges, such as railway cars, but they cost a dollar or more making them too expensive for lower cost items in the supply chain.

Passive tags have no battery, they draw power from the reader, which sends out electromagnetic waves that induce a current to the tag's antennas. Tags can come be read only, write once, or fully writable. The writeable memory can be as little as 64 bits for passive tags and up to as much as 32 kB for active tags. This memory can be read or written very quickly, in some cases as fast as 200 tags/sec! Having some memory gives your process the ability to read or write any data to it that you wish. This includes test data, location data, or even the new EPC codes.

Electronic Product Code (EPC) is an evolution of the Universal Product Code (UPC) technology providing identification without line of sight requirements. The EPC tags carry a unique product code as defined in the Auto-ID specification. EPC labels are more than a radio "barcode," because they contain individual item serial numbers and other information such as manufacturing location, date codes and other vital supply chain data. This information is stored on a small silicon chip. These elements will be combined with a network of tags, readers, and computers to enable -- in the case of business adoption -- manufacturers and retailers the opportunity to accurately track inventory in real time.

Yes. Radio waves bounce off metal and are absorbed by water at higher frequencies. While that can make tracking metal objects or those with high water content problematic, well-planned system design and engineering can solve these issues.

Chips in RF tags can be read-write or read-only. 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, or interrogator. Read-write tags are useful in some specialized applications, but since they are more expensive than read-only chips, they are impractical for tracking inexpensive items. Some read-only microchips have information stored on them durinsg the manufacturing process. The information on such chips can never been changed. A more flexible option is to use something called electrically erasable programmable read-only memory, or EEPROM. With EEPROM, the data can be overwritten using a special electronic process.

Another problem readers have is reading a lot of chips in the same field. Tag collision occurs when more than one chip reflects back a signal at the same time, confusing the reader. Different vendors have developed different systems for having the tags respond to the reader one at a time. Since they can be read in milliseconds, it appears that all the tags are being read simultaneously.

RFID Tags are available with storage capabilities from 512 bytes to 4MB. It largely depends on vendor and whether the tag is passive or active. Data stored in a tag will be determined by the application of the system and appropriate standards. For example, a tag could provide identification for an item being manufactured, goods in transit, or even the short-range location and identity of a vehicle, animal, or individual. This fundamental data often is referred to as a "license plate code," similar to the information that is stored on a bar code label.

When linked to a database, additional information may be accessed through the reader such as item stock number, current location, status, selling price, and batch code. Alternatively, an RFID transponder may carry specific information or instructions immediately available upon reading, without the need to reference a database to determine the meaning of a code. For example, the desired color of paint on a car that is entering the paint assembly area on the production line, or a manifest to accompany a shipment of goods.

Yes, RFID transponders have already been combined with a number of different sensors, including those that can detect and record temperature and humidity. Tags used to track items moving through the supply chain can generate alerts if the environmental conditions have changed, especially if it is critical to the use and storage of the item, like in refrigeration units.

Initially, in the technical field, RFID transponder was the term used to designate an electronic module which is able to Transmit information and respond with information. Recently, different fields in which Radio Frequency Identification is prevalent have developed a new jargon to designate the same thing, such as Smart Label or RFID Tag. "Smart labels" are a particularly innovative form of RFID transponder and operate in much the same way. However, a smart label consists of an adhesive label that is embedded with an ultra-thin RFID transponder "inlay" (the tag IC plus printed antenna). Smart labels combine the read range and unattended processing capability of RFID with the convenience and flexibility of on-demand label printing. Smart labels also can be pre-printed and pre-coded for use. In on-demand applications, the tag inlay can be encoded with fixed or variable data and tested before the label is printed, while the label can contain all the bar codes, text, and graphics used in established applications. Smart labels are called "smart" because of the flexible capabilities provided by the silicon chip embedded in the tag inlay. A read/write smart label also can be programmed and reprogrammed in use, following initial coding during the label production process.

There are many questions regarding the tags. Do the tags work with water? Are they distorted by metal, what temperature do they operate at? The way radio waves are affected by water. . Those with high water content, metal products and those where there are exposed to extreme high and low temperatures, are a challenge. Good system design and engineering can overcome any of these shortcomings and that is why there are different RFID transponders for different applications. Our goal is to create a system in which any tag can be used to identify a product, as long as it has an Electronic Product Code, and communicates using basic communication standards.

Smart Band consists of an RFID microchip (with a unique factory imbedded serial num ber) and antenna inlet sealed inside a non-transferable and secure wristband.