When considering an RFID system, one of the most attractive features is its ability to provide data in real-time. But what is real-time, since whenever we read RFID data - or any data for that matter - its immediacy is, by its very nature, past time. As good as antennas are, they cannot solve the time delay problem in a passive tag, active tag or BAP tag systems because a time delay always exists - albeit a very small time delay.
Real-Time Reads Vary For RFID Systems
Real-time should not be confused with continuous time. Active RFID systems give data continuously if they are programmed to do so. Passive RFID systems and BAP systems also can be configured to give continuous information, often more economically than active RFID systems deliver it.
More readers would be utilized in such a system. However, continuous reads on any of the platforms still have a "real time" time delay factor even at the point of direct data input in software and even more so when subjected to human reads and interpretation.
Because of this delay, it may be prudent when designing a system to eliminate the human component and build into the RFID system automatic responses triggered by software. Where high-speed manufacturing is taking place or in scientific experimentation, closer real-time reads may be necessary for accuracy.
Consider Frequency Of RFID System
The frequency of a radio wave affects how fast tags can be read (as well as how far they can be read from and the surroundings in which they can or cannot operate). When purchasers consider tag speed, frequencies are considered: a hertz being a unit of frequency of one radio wave cycle per second.
Low-frequency tags (LF) have a frequency of cycle measured in kilohertz (kHz), high-frequency tags (HF and UHF) have frequency measured in megahertz (MHz) and microwave tags are measured in thousands of megahertz to gigahertz (Hz) levels. These tag frequencies are provided in tag descriptions in the literature distributed by tag manufacturers.
Manufacturing Decisions Affect Speed Of Read
Antennas catch and broadcast these frequencies sometimes efficiently and sometimes not. Inlay manufacturers must pair antenna design to chip type when creating inlays, converters must use appropriate encapsulation materials to facilitate wave penetration and RFID system installers must consider variables such as antenna positioning and polarity to guarantee fast, accurate reads.
Therefore, when data is transferred between tag and reader, RFID frequencies affect the speed of the transfer. Although modifications can be made, usually, the higher the frequency, the faster the read and the closer to true real-time the read will be.
Ask Questions When Choosing RFID System
Phrases like “faster than a speeding bullet” and “in the blink of an eye” are obsolete because, ironically, in some scenarios they are slow. Real-time readings of anything, including RFID readings, are impossible to achieve, but readings are close, very close to happenings especially with the use of technologies such as RFID, which reads in milliseconds.
The questions for you, the one implementing an RFID system, are
- What is your definition of real-time?
- What is your need for real-time?
- Is real-time more important than other variables associated with frequency: read range, tag size, legal restrictions, cost
Upon answering these questions, you are closer to the design of your ideal RFID system. Experts in the field, including representatives from Metalcraft, will help guide you through all the peculiarities of RFID tagging. In real-time? No, but promptly.
About the Author: Colynn Black