labels have many different classifications.
active RFID tags and passive tags
In practical application,the electronic tag must be powered to work.Although its power consumption is very low,the tag can be divided into active RFID tags and passive tags according to different ways of acquiring power.
■ Active RFID tag is powered by the internal battery of the tag. It has sufficient power, high reliability and long signal transmission distance.The disadvantages of active RFID label are high price,large volume and limited service life.With the battery power consumption in the label, the distance of data transmission will be smaller and smaller,which will affect the normal operation of the system.
■ The passive tag does not have a battery inside,so it can work normally only by providing energy from the outside.The passive tag generates electric energy through the antenna and coil. When the tag enters the working area of the system and the antenna receives a specific electromagnetic wave, the coil will generate induced current.So passive tags have a permanent life often used in places where label information needs to be read and written every day or frequently,and passive label supports long-term data transmission and permanent data storage.The disadvantage of passive label is that the power is relatively weak, so the data transmission distance and signal strength are limited.But its price,volume and ease of use make it the first choice.
The following are for passive tags only
read only label and read-write label
■ Read only label internal read only memory.Identification information with label stored in ROM.This information can be written to ROM by the manufacturer during label manufacturing,and also be written by the user according to the specific application purpose when the label is used,but this information can only be written once.The read-only tag also has a buffer memory for temporarily storing the information waiting for the antenna to send after modulation.Read only labels are generally small in capacity, so they are used as identification labels.
■ In addition to ROM and buffer memory,the memory inside the read-write label also has inactive programmable memory.This kind of memory is EEPROM,In addition to the function of storing data, it also has the function of allowing multiple erasures of original data and rewriting data under appropriate conditions.read-write label may also have RAM（RANDOM ACCESS MEMORY）to store temporary data generated during label reaction and data transmission.Read-write labels store large amount of data, which are usually user programmable,there are also a lot of other information stored in the label, such as production information, anti-counterfeiting check code, etc.In practical application, information is stored in tags, and most of the information can be obtained by reading tags, instead of having to connect to the database for information reading.
Each label has a unique code, which is stored in ROM,so the label cannot be copied.