How RFID works

With The Internet of things The development of , Radio frequency identification （RFID） Technology is more and more applied to industrial sites .RFID Our English full name is “Radio Frequency IDenTIficaTIon”, Chinese translation for “ Radio frequency identification ”. It's in 20 century 50 A wireless identification technology born in the s , It can be done without contact , Use the radio （radio） To identify . Depending on the radio frequency ,RFID The system can be divided into low frequencies 、 high frequency 、 UHF and microwave .

Low frequency system （LF）：RFID The radio wave frequency is lower than 134KHz The system of , follow ISO/IEC 18000-2 standard ;

High frequency system （HF）：RFID The radio frequency is 13.56MHz The system of , follow ISO/IEC 15693（ compatible ISO/IEC 18000-3）、ISO14443 standard ;

UHF system （UF）：RFID The radio frequency is 860~960MHz Between systems , follow ISO/IEC 18000-6B/C standard ;

Microwave system （Microwave）：RFID The radio frequency is 2.4GHz The system of , follow ISO/IEC 18000-4 standard ;

One RFID The system is generally composed of four parts ： Electronics label 、 The antenna 、 Reader writer and application software .

Electronic labels are similar to bar codes in bar code systems , A chip that can be erased is integrated inside , For storing information . According to whether there is The battery , Electronic labels are divided into active and passive . Active electronic tag with battery , Compared with passive electronic tags , The readable distance is far ;

The antenna ： Generally connected to the reader writer , Used to receive / Send electromagnetic waves ;

Reader writer ： It is used to read the data of the electronic tag and transmit it to the upper computer application Software In the system ; Some can also write data into electronic labels ;

Application software ： be based on PC or PLC The software system of , It is used to process the data sent by the reader writer ;

RFID The system is shown in the figure below ：

RFID The working principle of the system is as follows ：

The reader / writer sends out electromagnetic waves of a certain frequency through its antenna ; When the electronic tag enters the working range of the transmitting antenna, its internal induction current is generated and activated , So the information stored in it is sent out through the internal antenna ; The antenna of the reader / writer receives the carrier signal from the electronic tag , Send it to the reader writer ; The reader / writer demodulates and decodes the received signal , And send the processed data to the upper computer or PLC Processing system .