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RFID tags - Frequently Asked QuestionsIf you have a question that isn't listed below, please send it to us at info @ arnlea.com and we will try our best to find the answer. Further information about barcode technology is also available at www.aimglobalorg.com.
The antenna emits radio signals to activate the tag and read and write data to it. Antennas are the conduits between the tag and the transceiver, which controls the system's data acquisition and communication. Antennas are available in a variety of shapes and sizes; they can be built into a doorframe to receive tag data from persons or things passing through the door, or mounted at a motorway toll booth to monitor the traffic passing by. The electromagnetic field produced by the antenna can be constantly present when multiple tags are expected continually. If constant interrogation is not required, the field can be activated by a sensor device.
RFID tags are categorised as either active or passive. Active RFID tags are powered by an internal battery and are typically read/write, i.e., tag data can be rewritten and/or modified. An active tag's memory size varies according to application requirements; some systems operate with up to 1MB of memory. In a typical read/write RFID work-in-process system, a tag might give a machine a set of instructions, and the machine would then report its performance to the tag. This encoded data would then become part of the tagged part's history. The battery-supplied power of an active tag generally gives it a longer read range. The trade off is greater size, greater cost, and a limited operational life (typically 3-5 years, depending upon operating temperatures and battery type). Passive RFID tags operate without a separate external power source
and obtain operating power RFID systems are also distinguished by their frequency ranges. Low-frequency (30 KHz to 500 KHz) systems have short reading ranges and lower system costs. They are most commonly used in security access, asset tracking, and animal identification applications. High-frequency (850 MHz to 950 MHz and 2.4 GHz to 2.5 GHz) systems, offering long read ranges (greater than 90 feet) and high reading speeds, are used for such applications as railroad car tracking and automated toll collection. However, the higher performance of high-frequency RFID systems incurs higher system costs. The significant advantage of all types of RFID systems is the non-contact, non-line-of-sight nature of the technology. Tags can be read through a variety of substances such as snow, fog, ice, paint, crusted grime, and other visually and environmentally challenging conditions, where barcodes or other optically read technologies would be useless. RFID tags can also be read in challenging circumstances at remarkable speeds, in most cases responding in less than 100 milliseconds. The read/write capability of an active RFID system is also a significant advantage in interactive applications such as work-in-process or maintenance tracking. Though it is a higher initial cost, the total cost of ownership is considerably less than barcode technology and RFID has become indispensable for a wide range of automated data collection and identification applications that would not be possible otherwise. Developments in RFID technology continue to yield larger memory
capacities, wider reading ranges, and faster processing. It is highly
unlikely that the technology will ultimately replace barcode - even
with the inevitable reduction in raw materials coupled with economies
of scale, the integrated circuit in an RF tag will never be as cost-effective
as a barcode label. However, RFID will continue to grow in its established
niches where barcode or other optical technologies are not effective.
If some standards commonality is achieved - whereby RFID equipment
from different manufacturers can be used interchangeably - the market
will very likely grow exponentially Like barcodes, RFID tags can be used in a write-once, read-many
mode where information written onto the tag remains with it for
the rest of its life. However, unlike barcodes, the contents of
a read-write RFID tag can be modified during the life of the equipment
or tool it identifies. Therefore, different information can be collected
and stored on the RFID tag as the asset moves through the manufacturing
process, is being inspected/maintained in the field, or during repair. The read range and reliability of some RFID tags are also affected by proximity to some metals, therefore experience is recommended when mounting or embedding RFID tags in metal. Arnlea Systems offer a wealth of proven industrial experience in this area. Depending on the type of RFID tag, some maintenance may be required
to 'refresh' the contents. As a rule, Arnlea use RFID tags that
require no maintenance.
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A basic RFID
(Radio Frequency Identification)
system consists of three components: 
Often
the antenna is packaged with the transceiver and decoder to become
a reader which can be configured either as a handheld or a fixed-mount
device. The reader emits radio waves in ranges of anywhere from
one inch to 100 feet or more, depending upon its power output and
the radio frequency used. When an RFID tag passes through the electromagnetic
zone, it detects the reader's activation signal. The reader decodes
the data encoded in the tag's integrated circuit (silicon chip)
and the data is passed to the host computer for processing.
RFID
tags come in a wide variety of shapes and sizes. Animal tracking
tags, inserted beneath the skin, can be as small as a pencil lead
in diameter and one-half inch in length. Tags can be screw-shaped
to identify trees or wooden items, or credit-card shaped for use
in access applications. The anti-theft hard plastic tags attached
to merchandise in stores are RFID tags. In addition, heavy-duty
transponders used to track lorries and railroad cars for maintenance
and location tracking applications are RFID tags. |
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