* What will be identified?
* What type of environment will the RFID system be in?
* Will there be electrical noise, temperature extremes, high humidity or harsh chemicals?
* How many tags will be needed?
* How many read stations will be needed?
* How fast will the tags be moving?
* What read range is needed?
* How much information will be transferred to and from the tags?
* How often will the tags be read and written to?
* Will the RFID system be reporting to a PC or a PLC?
* Will more than one tag need to be read at the same time?
However these questions are not easy to answer, unless we go through some basic definitions and understanding of each component of a RFID system. Few terms that are essential to understand are:
Active tag: An RF tag powered by an external source, like battery.
Passive tag: An RF tag that draws its electrical power from radio waves.
Antenna: This sends and receives information from RF tags. Also known as the interrogator or read-write head.
Reader: This device powers the antenna. It receives tag data from the antenna, then filters, boosts and transmits the data to the controller interface.
Interface: The device that translates signals from the reader into a computer language and transfers that information to a Personal Computer or a Programmable Logic Controller (PLC).
EEPROM: Electrically Erasable Programmable Read-Only Memory. A memory chip that holds its content without power. It functions like nonvolatile RAM.
RF portal: The effective broadcast area of the antenna. It is also known as saturation area.
RF tag: This is an assembly of a memory chip, a substrate and an antenna. It is also known as a transponder or data carrier.
Tomorrow I will continue with the explanation of how these defined pieces work together.