What is RFID?

Illustrated RFID Tag

Radio Frequency Identification (RFID) is now an easy to install and even easier to use technology. With many applications that can benefit from RFID, it makes sense for everyone to at least look at it.


We talk about Radio Frequency Identification, but what is it, really? RFID is a way of identifying something without line of site. Traditionally, barcodes are used to identify items. Barcode technology is a great technology if the barcode can be seen by the reader. This usually means you must restrict the item being read to be at a precise visible location and orientation.

Forklift passing through an RFID Portal

RFID, on the other hand, can read items that enter, exit, or are in a zone. There does not have to be a line of sight. However, RFID is not a “one size fits all” solution. There are considerations to help you implement the RFID technology for your application. These considerations can be read ranges, what type of materials you are tracking, such as metal and liquids, and what type of interference may be in the zone, such as heavy machinery. Radio waves can sometimes be influenced by various factors. For example, they have trouble passing through metals or liquids. Also, radio waves can bounce around depending on the environment. An RFID expert can iron out these issues with a consultation which may include a site survey.


RFID makes use of many different radio wave technologies. The most common types of RFID are High Frequency (HF) and Ultra-High Frequency (UHF). Other technologies, such as Low Frequency (LF) are sometimes used, but usually only in very specialized circumstances.


HF (13.56 MHz) tags are often more complex because the implementation varies by vendor, uses many different standards, and has varying read range capabilities. Normally, HF is used in specialized applications that are unique to a single environment or process.


UHF (860-960MHz) tags, on the other hand, have become more common place. There are dozens of vendors with a product offering using UHF antennas that read Electronic Product Code Class 1 Generation 2 (EPC Gen 2). EPC Gen 2 is a standard with a unique code for each tag. Many of the tags can also have data written into it. Having data on the tag just makes the technology more powerful for expanding applications such as testing, field data retrieval, and verification.


The standardization of RFID UHF EPC tags has enabled many applications to depend on the interaction with the RFID Tag data. It’s now a proven technology that works. Hundreds of companies use UHF EPC tags daily to identify product movement, perform loss control, restrict access, ensure safety, increase quality, and more.


Tags can be Active or Passive. Active tags require a battery because they have a built-in transmitter. These tags continuously broadcast their data at preconfigured intervals and have a much larger read range (up to 300 feet or more). Although the reader hardware may be a bit less expensive, active tags typically cost more than passive tags. Also, depending on their broadcast rate, the batteries eventually run out and the tags will need to replaced, usually every 3-4 years.


Passive tags are usually used in applications where the read range are less than 10 feet. Depending on the size of the tag circuitry and antennas, larger tags can be read as far as 40 feet. Passive tags require the power of a reader to energize the circuit which bounces the signal back to an antenna, not much different from the way radar works. Passive tags tend to be much less expensive and last much longer than active tags (usually 10 plus years depending on the environment).


Reading the RFID tags requires an RFID reader. Most UHF RFID readers are designed to read either only active tags or only passive tags. However, some vendors are now coming out with hybrid readers that can read both. Based on demand, UHF readers are now available in a variety of flavors. While some of the newer UHF readers have a built-in antenna, most readers connect their antennas externally with a coaxial cable. UHF antennas also come in various sizes and shapes to help with varying read ranges and different shaped zones. Depending on the needs of the environment, antennas and readers are available in different shapes, colors and sizes for aesthetics and real estate limitations.


EPC Gen 2 tags have a 96-bit unique EPC number, a 32 or 64-bit tag identifier (TID) number, and a preset amount of user memory. The user memory may be from 0 bits (no memory) to 2048 bits. Some tags may have even more memory, although some legacy readers may not be able to access it. Some tags also have a 32-bit access password and a 32 bit kill password to permanently disable the tag. Most applications will only access the EPC number and the user data. If you use EPC Gen 2 tags most RFID vendors have readers that will read them right out of the box.


UHF RFID readers usually will read EPC, TID, and the user memory of the EPC RFID tags in range. Some readers can also let you know whether a tag is approaching or departing the read range of the read zone. Other readers include the ability to write custom/user data into a tags memory. In nearly all instances the reader is managed by software to coordinate what to write into a tag and what to do with the values when they are read.


One of the challenges still facing the RFID industry is that vendors have not yet adopted a standard protocol for communicating between the software and the hardware. In other words, each reader speaks a different language. Therefore, the users are limited to working with hardware that is developed for the software application they are using. Or they will need a software engineer to write the communications interface to their application. The good news is that most of the hardware vendors do provide a good application program interface to make it easier to interface their readers to the application.


If you can, try and work with an off the shelf application that has experience communicating with multiple vendor’s equipment. Good chance is they will already have the interface or can quickly add the interface to their application. There are many types of application where RFID is economically feasible with a quick turn around on the ROI.


Some of the types of applications that take advantage of RFID capabilities are inventory management, process control, loss control, quality control, location management, asset management, tool management, uniform management, and security/access control. As you implement multiple uses for RFID you’ll want to consider using different types of tags or standardizing on a single type throughout your enterprise.

BALLUFF RFID Tags for InformaTrac

The form factor of the tag comes in many shapes, sizes, colors, environmental considerations and costs, depending on the application. There are well over a thousand form factors available and many companies that will even customize a form factor to your specific design. Talk to your RFID vendor about existing, off-the-shelf tags that fit just about any application. A few considerations are screw tags, PVC disk tags, clear disk tags, paper label tags, hard tags for industrial use, tags that can survive extreme temperatures, wind shield tags, key fobs, card tags, card keys, and so on.


RFID is a great technology for tracking the locations of inventory, jobs, assets and personnel as they move through processes or different zones of a facility. You can get fast results, generate alarms, get location history, control flow, and store the history in an easy access database. For more information, click here or give InformaTrac a call at (866) 619-7411 and we can show you how RFID will work for you.

InformaTrac Logo

No Comments

Be the first to start a conversation

Leave a Reply

Scroll to Top