In the Internet of Things, RFID tags carry the equivalent of making objects have a virtual "identity" on the network, through RFID readers to read the information on the RFID tags, you can query and dynamically track the properties, characteristics and other information of the items attached to the tags in real time on the network. The "Internet of Things" can achieve global tracking and information sharing, significantly improve management and operational efficiency, reduce costs, and bring deep-seated changes to all aspects of the global supply chain (warehousing and logistics, manufacturing, item tracking, commercial retail, public services and other industries). To achieve these, it is indispensable to RFID readers to collect RFID tag information "anytime, anywhere" and to achieve seamless and comprehensive coverage of the Internet of Things.
RFID reader as an integral part of the RFID system, can also be subdivided into RFID antenna and RFID reader two parts. RFID reader through the RFID antenna launch signal "wake up" and transmit instructions to RFID tags, and receive UHF RFID tags back to the signal. After the initial filtering and processing of the signal, the RFID tag information is acquired and analysed, and the useful data is interacted with the data management system through the network. The data management system can be taken up by simple local software, or it can be a distributed ERP management software with integrated RFID management module.
The communication process of RFID system is the process of RFID reader giving information to RFID tag and getting information on the tag. Because the passive RFID tag itself has no power supply, so must rely on the energy obtained from the RFID reader to send the radio frequency signal (beam power technology), and RFID tag to obtain energy only enough to supply the electronic tag itself, there is no excess energy available for the radio frequency signal source work, must use passive reflection modulation technology to achieve the communication between RFID reader and RFID tag. And RFID label in the answer process to the reader transmits the continuous wave radio frequency signal to modulate, then will have modulated the radio frequency signal reflects back, is the reader receives the decoding, completes the information transmission function.
RFID reader's composition. RFID reader generally by the radio frequency module, control processing module and antenna composition, which radio frequency module is mainly responsible for the radio frequency signal and baseband signal between the conversion and data information modulation demodulation; Control processing module as RFID reader core, mainly responsible for and platform system and RFID tag between the communication management, baseband signal coding and decoding, the implementation of anti-collision algorithm, data transmission process The antenna is mainly responsible for receiving or transmitting the RF signal to achieve the transmission of data information and energy. RFID read-write's role.
1、Responsible for the communication with the RFID passive tag, the RFID tag implementation initialization, read and write the data information within the RFID tag, and responsible for managing the RFID tag, such as making its function invalid, etc.; 2、Responsible for communication with the computer platform system, on the one hand, the data information read from the RFID tags will be transmitted to the platform, on the other hand, the platform system control information will be received, to complete the specific application action; 3, through the radio frequency way to the passive RFID label transmission energy, for the active RFID tag its also can read RFID label built-in battery related information, such as power, etc.. 4, RFID read-write installation is convenient, generally can by the application software to manage and control, so can remote maintenance; 5, RFID read-write has the ability to prevent collision to identify multiple tags, can identify multiple mobile electronic tags, can complete multiple tags at the same time access, with multiple tags at the same time read the information to prevent collision ability; 6, RFID read-write has relatively strong compatibility, compatible with the most common communication protocol, can communicate with a variety of electronic tags.
RFID read-write's structure form. RFID read-write structure has no fixed form, mainly according to the need and application scene, to design RFID read-write structure and appearance shape, common RFID read-write mainly have fixed RFID read-write, handheld read-write, one read-write, separate components read-write, industrial read head, OEM module type read-write and so on. RFID reader and writer each function realization method.
1、Event scheduling The use of PIC32 chip to achieve simple RFID identification, display and communication event scheduling function. 2、External communication Use Pmod NIC peripheral module to achieve Ethernet communication function. 3、RFID signal processing Use PIC32 chip to achieve basic signal sampling, shaping, digital filtering and decoding functions. 4、Human Machine Interface All event scheduling information, debugging information and the identified RFID tag ID number are displayed to the operator via the Pmod CLS peripheral module.
Parameters of the RFID reader. 1、Output power This parameter is related to the application, on the one hand to meet the needs of the application, on the other hand also to meet the regulatory requirements, i.e. to meet the wireless frequency specification and health requirements. 2、Working mode Divided into full duplex, half duplex and time sequence three. 3、Working frequency The working frequency is the same as that of RFID electronic tags, but the frequency of RFID systems is generally determined by the frequency of RFID readers. 4、Output interface Common interfaces include: 5G, 4G, WiFi, USB, RS-485, RS-232, etc., according to the needs of the scene to choose. 5、Priority mode Divided into RFID reader priority and RFID tag priority, which RFID reader priority means that RFID reader first to RFID tags to transmit RF energy and command, while RFID tag priority RFID reader only send equal amplitude, without information RF energy, both are to be activated after the RFID tag before starting to receive commands, send data information.