16-02-2010, 07:42 PM
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RADIO FREQUENCY IDENTIFICATION
INTRODUCTION
60 years old
Uses radio waves to pass identity information between product tag & a reader device
Rapidly growing segment of AIDC industry.
Started to use along with bar code technology
Pallet tracking, stocking, cartons tracking, inventory tracking.
No need for line of sight as in the case of bar code technology
Wireless data transmission with read-write technology
RFID tags embeds a micro chip with antenna and with a EPC.
Entire shipping container, pallet, case or shopping cart can be scanned within seconds
Elements of an RFID system
RFID tags
RFID readers
Antennas and choice of radio characteristics
Computer network
RFID tags
Basic building block of an RFID system
Consists of an antenna & a silicon chip
Silicon chip has- a radio receiver, radio modulator, control logic, some amount of memory, & a power system
Basically two types of tags-active tags and passive tags .
Also a combination of both the tags called semi-passive tags available
Tags can communicate with ay sort of a reader
But they also can be secure by asking for passwords
Information can be burned on it by the manufacturer or by the end user and can also be re-programmed
Chips can also have sensors such as pressure sensors on tag on a tire to check tire pressure
Can also have self destructive or kill feature
Multiple tags have to be singulated when a reader wants to read it
Active tags
The power system for the tag being provided by the battery present in the tag.
The life of the tag limited to the life of the battery
Primary advantages include reading range & reliability.
With proper antenna on both the reader as well as the tag a 915Mhz tag can be read from a distance of 100 feet or more
They tend to be reliable because they do not need a continuous radio signal to power their electronics
Passive tags
Smaller than active tags
Cheaper than active tags
Do not require a battery
They have a longer life
They could work even many decades after they had been manufactured
Electronic product code (EPC)
Next generation bar code or Universal Product Code (UPC).
Can carry more data than the UPC and can also be reprogrammed
Consists of a series of numbers that can identify manufacturer and product type
Also include extra set of digits to identify unique set of products
No line of sight limitation as in bar code
Sturdier than bar codes so can be used in adverse conditions
Can be affixed or embedded on the product or inside the item
RFID readers
Sends a pulse of a radio energy and listens for the tagâ„¢s response
Tag detects it and sends back a response that contains its serial number and other information as well
In simple systems the readerâ„¢s energy functioned as an on-off switch
In more sophisticated systems readers RF signal can contain commands to the tag instructions to read or write memory of the tag and even passwords
Single mode and multi mode readers
Readers can sent signals continuously or as and when required
Different sizes-ranging from desktop PC to the size of a stamp
Antennas and radios
Most RFID systems utilize unlicensed spectrum set aside without a radio license
Popular bands are low frequency band at 125-134.2khz, the high frequency band at 13,56Mhz, the ultra high frequency band at 915Mhz and the industrial, scientific, and medical bands at 2.4Ghz
Larger the antenna on the tag and the reader the better the RFID system would work
Large antennas are more efficient in transmitting and receiving radio power than small antennas
A large antenna on the reader means that more power can be sent to the tag and more of the tags energy can be collected
A large antenna on the tag means that more of the power can be collected and used to power the chip
A large antenna on the chip means that more power can be transmitted back to the reader
The network
Tags transmit numbers and nothing more
The reader sends the number to the computer with the EPC the serial number will be sent to a network of computers that make up the Object Name Service , a large distributed database that will track a variety of pieces of information about the objects that have been assigned EPC codes
The data base contains both root servers and distributed servers at each company that creates products labeled with EPC
Given any EPC code the root servers would tell which companyâ„¢s servers to go to and then the companyâ„¢s servers would explain what the EPC code means
Applications of an RFID system
Inventory control
Manufacturing
Logistics
Warehousing
Retailing
Challenges faced by the RFID system
Technological development.
Common technical and transmission standards.
Wireless spectrum operation.
Privacy and security concerns.
Cost barriers especially for small-medium enterprises.
Case study
Johnson Controls produces truck and car seat varieties for NUMMI (a joint manufacturing concern of Toyota and General Motors)
Johnson directly deliveries the seats to the NUMMI production line
NUMMI uses JIT
Johnson Controls will have to deliver the seats corresponding the NUMMI production line needs
NUMMI sends a serial list of required seats every hour
Mistakes in loading the seats in serial line can bring the NUMMI production to a standstill
Operators on production, inventory, & shipping areas are prone to errors
Bar codes would be dirtied and scrapped and also would be misread
RFID provides a solution to the whole problem
Installed read-write system for truck seat production line
Installed read only system for car seat production line
Installed read-write system for inventory areas
Time savings & flexibility
No need to regroup car and truck seat models in their production line
Used both low & high frequencies tags
Conclusion
With emerging technologies and reduction in the tag costs RFID can be implemented in small and medium scale industries
It would be possible to track products from any where in the world using the GPS system
Can become a part of daily life
Growth apart from manufacturing sector such medical, healthcare, animal and people tracking, space research etc.
