Tag, also known as electronic tag or smart tag, is a chip with antenna in memory, which stores information that can identify the target. RFID tag has the characteristics of persistence, strong penetration of information reception and transmission, large storage capacity and variety of information. Some RFID tags support reading and writing functions, and the information of the target object can be updated at any time. The interpreter is divided into two types: Handheld and fixed, which is composed of transmitter, receiver, control module and transceiver. The transceiver is connected with the control computer or PLC to realize its communication function.