Playing Off HF & UHF RFID
The third and final part in our series about today’s smart asset IDs and their best suited applications.
In our first post for 2014 we want to dig a little deeper into the world of RFID and examine the most commonly used frequencies in asset management to help organisations determine the best-suited system for their application.
Just like a radio needs to be tuned to different frequencies for different channels, RFID tags and readers must be of the same frequency in order to communicate. And, because RFID frequency determines the way the system will perform and operate, it is important for organisations to develop some understanding of these issues when evaluating RFID-based asset intelligence systems for their operations.
There are 4 main frequency bands that RFID systems operate at around the world. HF and UHF RFID systems are the frequencies most commonly used for asset management, track and trace and industrial applications.
Low frequency [LF]
LF RFID systems operate in the 125 – 134 kHz range so they only provide a short read range [most often the reader needs direct contact on the tag] and a slower read speed than higher frequencies. Whilst they are not as susceptible to environmental interference as other frequencies, because of the read limitations, LF is not often used in industrial operations. Typical applications include access control, animal tracking and point-of-sale.
High frequency [HF]
HF RFID systems operate at 13.56 MHz so they have a higher read range and speed than LF systems, but not as much as UHF. HF is often chosen for its reliable operation as it can better avoid communication gaps or blind spots. HF RFID can also be less vulnerable [than UHF] to interference from metals, liquids, carbon substances, electromagnetic waves and other conducting objects. Having said this, newer UHF solutions are often able to overcome these issues. Whilst HF RFID has a shorter read range than UHF, HF tags currently still have a greater memory capacity than UHF allowing more data to be stored on the tag. This may be advantageous for remote operations where connectivity to a database or the internet is limited. HF systems also use less power because they don’t transmit data over great distances. HF systems are cheaper than UHF, however the price/performance gap is closing as supply and demand for UHF increases. HF tags have had a broad array of form factors and sizes. Typical applications include item-level asset tracking, track and trace, hospital patients, and airline baggage. They are also often used to collect in-field data during maintenance, audits and inspections for equipment or assets that need regular checking.
Ultra high frequency [UHF]
Most UHF RFID systems operate between 860 – 960 MHz frequencies, however every country uses a different frequency. GS1 have put together a summary of these regulations which you can read here. The primary rationale for using UHF is its greater read range and speed of data transfer, but this can vary depending on the tag type and reader capability. UHF RFID is more likely to solve fast-paced, complex applications that require multiple tags to be read at once. Some systems can handle reading as many as 200 tags at a time. They can also transfer data over several metres and without requiring line of sight. For example, Relegen has implemented a system at a Mongolian mine site where fixed readers can read UHF tags as far away as 10 metres. Whilst UHF systems still tend to cost more than HF, because of their speed/range capabilities they can result in significant time, labour and cost savings, productivity gains and increases in output which offset the initial implementation cost. Typical applications include stocktaking, inventory control, supply chain applications, minerals and raw materials tracking, motorway tolls and more. UHF RFID applications are set to expand over time as the technology becomes commoditised.
Super high frequency [SHF]
SHF RFID systems operate at 2.4 GHz. and 5.7 – 5.8 GHz frequencies. Tags in this frequency are often referred to as microwave tags. SHF systems offer higher read ranges than UHF however there are several downsides to this technology. Firstly SHF systems consume more energy than lower frequencies. They are also more expensive than UHF tags and can suffer from even more interference issues than UHF. Some wireless networks [such as WiFi] may also interfere with microwave RFID systems. For this reason SHF systems are not currently used in asset management. There is no international standard governing the use of SHF RFID and it is restricted in a number of countries.
Summing up
RFID-based asset intelligence systems enable users to significantly improve data quality, accelerate production output, minimise errors, optimize and innovate business processes and achieve substantial cost savings in time and labour. Overall it can be a powerful technology for the right application. However every project is unique and requires careful planning and testing. In many cases, organisations will start with a limited installation or a pilot project before deploying the technology on a larger scale.
We hope this series of posts has given you a better understanding of the factors that can affect the success of your asset identification/asset intelligence project. It is important to seek independent advice when selecting RFID tags and readers as there are many other issues to consider other than what we’ve been able to cover in these introductory posts. Of course, Relegen is here to help you navigate this landscape successfully. Our assetDNA software and mobile application works across all RFID platforms. Call +61 (0)2 9998 9000 or email sales@relegen.com to learn more today!