What is an Asset?
An asset is any piece of equipment or property that has value to a person or company. The significance of the asset can be of monetary or of intrinsic value.
What Type of Assets Can Be Tracked With RFID?
The assets currently being tracked throughout the world range in size, shape, and material. Below are a few examples of assets:
|METAL ASSETS||PLASTIC ASSETS||MISC. ASSETS|
What Can Be Accomplished With RFID and Assets?
- Locate a specific asset in a room, yard, or warehouse.
- Track an asset’s journey through a manufacturing, sterilization, or repair process.
- Keep accurate historical records of repairs, usage, etc.
- Manage inventory in a fixed or mobile location.
- Prevent assets from being lost or stolen.
- Create accountability by allowing assets to be checked in and out.
What Type of Equipment is Required For an Asset Tracking System?
The bare minimum RFID system consists of the following:
An RFID Reader is the brains of an RFID systems and, with the aid of software, it can be programmed to perform at specific times or transmit certain power levels. Different types of RFID readers are available to operate in specific environments or applications. Because asset tracking is a broad application, most readers will work well, but a few classifications exist to help narrow down the ideal reader for each application.
Ideal for performing maintenance operations, locating assets, checking
items in/out, and writing tags.
Ideal for close range reading, checking items in/out, and writing tags.
Ideal for portal, conveyor, or general area reading and can be used with a
variety of antennas to create a vast number of read zone coverage options
to suit the application and/or environment.
A lower cost alternative to a fixed reader. An integrated reader is an antenna
and reader combined in one enclosure and is ideal for lower volume
applications and/or applications where a broad coverage area isn’t required.
Applications containing processes with accelerated movement demand a reader that can process tag reads rapidly and, as such, typically require a fixed reader with high gain antennas (usually setup in a staggered fashion).
FOR MORE IN-DEPTH ARTICLES:
- Integrated VS Fixed RFID Readers
- How to Select a UHF RFID Reader
- Software, Firmware, & Middleware: What is the Difference?
RFID Antennas and Cables
RFID Antennas and cables work together with the reader, tags, and software to complete the RFID system. Antennas are made with different technical specifications to fit a wide variety of applications. RFID Antennas can be sorted using four primary characteristics:
Each of these categories contain options that need to be completely understood before purchasing an antenna. Understanding the environment, read range needed, country of application, and angle of tag reads will help the user choose an option per category. Using the information gathered from each category above in addition to existing hardware specifications will help to determine the best antenna for individual applications.
Antenna cables are available in various lengths, insulation ratings, and connector types. It is imperative that the right cable be used in any given situation.
FOR MORE IN-DEPTH ARTICLES:
- RFID Antenna Cables: Getting the Highest Performance Possible
- 3 Guidelines for Choosing a Passive UHF RFID Antenna
- Circular Polarization vs. Linear Polarization: Which is the right RFID Antenna?
- Understanding Near-Field and Far-Field Antennas
What Type of RFID Tag is Used for Asset Tracking?
Determining the ideal RFID tag for an asset tracking application depends on the asset as well as its environment, read range needed, as well as any processes it must go through. The material of the asset will greatly affect the type tag required and the three most common groups of materials along with information on tags and attachment methods.
Even though metal causes RF interference, metal assets can be tracked using RFID. Metal-mount RFID tags are tuned for use on metal and, as such, can actually have greater read range than some of their counterparts.Metal-mount tags can be attached to assets a few different ways such as screws and rivets, epoxy, and embedded to name a few.
A company in Singapore is using metal-mount RFID tags to track steel drums wound with cabling they sell throughout the region. Applying a metal-mount tag on each drum as well as on each rack helps the company find specific drums of cabling without hassle. To date, the time spent searching for these drums has been reduced from 45 minutes down to less than 5 minutes.
There are quite a few RFID tags that are tuned for plastic and perform well. The main considerations for tagging plastic assets are tag size, shape, and method of attachment. Manufacturers suggest a specific set of attachment methods that are proven for each tag. The environment in which the tags will be used in also plays an important part in the selection process.Some tags are required to work in high-temperature or rugged environments which narrows down tag selection.
Many medical facilities use plastic tubing for multiple applications from blood pressure cuffs to IVs. A company in Minnesota is tracking tubing and connectors at the end of the tubes as a measure of patient safety. Applying RFID tags to the tubing ensures that the tubing is applied and coupled correctly, and also confirms none are reused to prevent contamination.
Assets comprised of wood, ceramic, glass, and other miscellaneous materials generally have a smaller selection of tags available for use. Attaching tags to these types of assets may be complex because of their material and surface type. For example, wood pallets are usually tagged using screws or the tags are embedded into the wood primarily due to the poor performance of adhesive on wood.
Distilleries and wineries around the country have thousands of hard to track assets worth millions of dollars. The barrels that contain the aging alcohol are stored in warehouses or cellars for years in order to mature and be sold. A company in South Africa is using an RFID system to establish records of batch and barrel location, movement, and historical cycles. Now the company can see real-time locations of these barrels as well as maintain complete records of each barrel.
After Deciding the Tag(s) to Use, How SHould They Be Positioned on the Asset?
The position of the tag on an asset is critical in receiving the desired read range. An easy way to understand and determine the correct way to position each tag is by using the SOAP method.
Generally speaking, the larger the tag, the longer the read range.
Tag orientation relative to the antenna matters. Try rotating the face of the tag on a flat surface to see which orientation produces the best read range.
The steeper the angle, the shorter the read range. When possible, ensure the front of the tag directly faces the antenna.
Test readability in a variety of spots on the item to find the ‘sweet spot’ that generates the best reads.Also, when mounting on metal, be sure to use a metal mount tag.
FOR MORE IN-DEPTH ARTICLES:
- The Best RFID Tag for Your Application: 7 Key Factors to Consider
- Pitch, Yaw, and Roll - Positioning RFID Tags
- 3 Things to Know About UHF RFID Tags
- 5 Ways to Attach RFID Tags
- 6 Factors that Affect RFID Read Range (SOAP)
Software is a critical piece of any RFID system; without it, readers can read tags, but no data will be collected or stored. A key piece of an asset management RFID system is the storage and utilization of the information collected from tag reads
OBSTACLES TO AVOID
There are two major problems that can occur with a system:
1.) READING INTENDED TAGGED ASSETS AT LESS THAN 99% ACCURACY)
If the RFID system in place is not reading close to 100% of the intended tags, there might be a problem with it or the facility. Testing the read range with different gain antennas, altering the transmit power on the reader and testing different tags will alleviate the accuracy problems.
If the system has been tested and is not the issue, completing a site survey with an RFID professional could be the answer. Some facilities have machines, electromagnetic waves, or objects and materials that could be interfering with the RF waves in the system. There are a few common items that typically interfere with RF waves such as liquids, metals, florescent lights, etc.
Like mentioned above, some tags are constructed specifically to mitigate those problems. If the facility or area the assets are being tracked in contains an abundance of these materials, the RF waves will reflect, refract, or absorb through the surfaces creating multipath. Multipath can create null zones in a read area so that read range is greatly affected. To mitigate multipath effects in a facility, RF shielding materials such as foam can be put in place.
2.) READING STRAY TAG READS
Too much read range can be bad thing. A system that contains tags with over 20 feet read range, a high gain antenna, and a high powered reader is typically a system better served for large inventory counts. If this system is used with reading and writing tags, conveyor belt applications, or even portal applications, it will pick up all tags in 20+ foot read range which can be a problem. If a company uses this system to track assets through their facility, it would not be accurate because any tag that is within that 20 foot range will be read causing hundreds of stray tag reads.
If stray tags reads become a problem, testing different tags, implementing a low-gain antenna, or turning the transmit power down in the reader will help to diminish these.
FOR MORE IN-DEPTH ARTICLES:
- Understanding and Planning For RFID Multipath Environments
- The Importance of Testing RFID Solutions
- RFID Tag Best Practices: 13 Tips for in the Field Tagging
- 6 Factors that Affect RFID Read Range
On paper, an RFID setup seems straightforward; however, every environment will affect an RFID system in different ways.Testing is the best way to ensure all components are working together to produce the desired results for the application. There are items available with a smaller price tag that can help with the testing process such as tag sample packs, rental equipment, and RF power mappers.