Concept
RF Identity System RFID System
is automatically identified by RF labels, readers, and computer networks. Typically, the reader is transmitted to the electromagnetic field in one region emission energy. When the radio frequency tag detects the signal of the reader, the signal is transmitted, and the reader receives the signal transmitted by the RF tag, decodes and verifies the accuracy of the data. To achieve the purpose of recognition.
Technology
Initially in the technical field, the transponder refers to an electronic module capable of transmitting information reply information. In recent years, due to the rapid development of radio frequency technology, the transponder has a new statement. And meanings, but also called smart labels or labels. RFID EQ Certificate Reader (reader) The antenna is wirelessly communicated with the RFID electronic tag, and read or write operations for the label identification code and memory data can be implemented. Typical readers include high frequency modules (transmitters and receivers), control units, and reader antennas.
RFID RF recognition is a non-contact automatic identification technology that automatically identifies the target object through the RF signal, and the relevant data is obtained, and the identification does not require manual intervention, it can work in various harsh environments. RFID technology recognizes high-speed moving objects and can simultaneously identify multiple labels, and quick and easy.
Tag (TAG): consists of a coupling element and a chip, each tag having a unique electronic coding, attached to the object to identify the target object.
reader: Read (sometimes writable) tag information, can be designed as a handheld RFID reader (such as: C5000W) or fixed reader;
Antenna: Transferring RF signals between labels and readers.
Working principle
After the label enters the magnetic field, the radio frequency signal emitted by the reader is sent to the product information stored in the chip with the energy obtained by the sensing current (Passive Tag, no Source label or passive label), or a signal (Active Tag, active tag or active tag) that actively transmits a frequency (Active Tag, Active Tag, or Active Tag), after reading information and decoding, sent to the central information system for related data processing.
A complete set of RFID systems is composed of readers and electronic tags (TAGs), which are related to the three parties of the transponder and application software systems. It is the radio wave energy that READER transmits a particular frequency to the Transponder to drive the Transponder circuit to send the internal data. At this time, the Reader receives the interpretation data sequentially, and the application is sent to the application.
The communication between the RFID card reader and the electronic tag can be generally divided into: Inductive Coupling and backscattercoupling. Generally, the low frequency RFID is mostly in the first type, while the higher frequency uses a second way.
reader can be read or read / write devices depending on the structure and technology used, and is the RFID system information control and processing center. The reader is usually composed of a coupling module, a transceiver module, a control module, and an interface unit. The reader and the transponder generally use half-duplex communication methods for information exchange, while the reader provides energy and timing to the passive transponder. In practical applications, management functions such as acquisition, processing, and remote transmission of object identification information can be further implemented by ethernet or WLAN or the like. The transponder is an information carrier of the RFID system. At present, most of the transponders are incorporated by the coupling original (coil, microstrip antenna, etc.) and microchip.
Working mode
The basic working mode of the RF Identification system is divided into full duplex and half-duplex system, and a timeout (SEQ) system. The full-duplex indicates that the RF tag and the reader can transmit information at the same time. Half-duplex indicates that the RF tag can transmit information between the radio frequency tag and the reader, but can only transmit information in one direction at the same time.
In a full-duplex and semi-duplex system, the RF label response is transmitted in the case of electromagnetic field or electromagnetic waves emitted by the reader. Since the signal of the RF tag is weak on the receiving antenna compared to the signal itself, the appropriate transmission method must be used to distinguish the signal of the RF tag to the signal of the reader. In practice, people are generally loaded to reflect the radio frequency tag data into reflected echo (especially for sourceless radio frequency label systems) using data transfer from RF labels to readers.
Timing method is contrary to it, the radiation of the reader is periodically disconnected in a short period of time. These intervals are identified by RF tags and are used to transmit data from RF labels to the reader. In fact, this is a typical radar working method. The disadvantage of the timing method is that the energy supply interruption of the RF tag is interrupted when the reader is sent, which must be compensated by loading a sufficiently large auxiliary capacitor or auxiliary battery.
Working frequency
Usually the frequency used in the reader is called the operating frequency of the RFID system. Common working frequencies have low frequency 125kHz, 134.2kHz, and 13.56MHz, and so on. The low frequency system generally refers to its operating frequency of less than 30 MHz, typical operating frequencies: 125kHz, 225kHz, 13.56m, etc. These frequency identification systems generally have corresponding international standards. The basic feature is that the cost of electronic tags is low. The amount of data stored in the label is small, the reading distance is short, the electronic label is diverse (card shape, cyclic, buttons, pen shape), reading antenna direction is not strong Wait.
High frequency system generally refers to its operating frequency than 400 MHz, typical operating frequency bands are: 915MHz, 2.45GHz, 5.8GHz, etc. High-frequency systems also have many international standards on these bands. The basic feature of the high-frequency system is that the cost of electronic tags and readers is high. The amount of data saved in the label is large. The reading distance is far (up to a few meters to ten meters), and the high-speed performance of the object is good. The shape is generally the card. The shades, the reading antenna and the electronic label antenna have strong directionality.
System advantage
RFID is an easy to control, simple and practical and particularly suitable for flexibility application technology for automated control, identifying do not need manual intervention, which can support read only Work mode also supports reading and writing mode, without contact or aiming; freely working in various harsh environments: short-range radio products are not afraid of bad environments such as oil stains, dust pollution, etc., can replace barcodes, for example with pipelines used in the factory Tracing objects; long-range RF products are used in traffic, identifying distances up to dozens of meters, such as automatic charges or identifying vehicle identity. The RFIT has the following aspects of the system advantage:
Read easy and fast: data reading does not require a light source, and even through an outfit. The effective recognition distance is larger, and the effective recognition distance can reach more than 30 meters, and the value of the "
" Label is entered into the magnetic field, the interpreter The information in which the information can be read, and multiple tags can be handled simultaneously to achieve bulk recognition;
data capacity : Data capacity 2D barcode (PDF417), maximum You can also store 2725 numbers; if the letter is included, the storage amount will be less; the RFID tag can be extended to dozens of K;
long service life, wide application range : Its radio communication makes it applicable to dust, oil and other highly polluted environments and radioactive environments, and its closed packaging makes its life exceeds the printing barcode;
The tag data can be dynamically changed : Using the programmer to write data, the function of the RFID tag interactively portally portable portable data file is given, and the write time is less than the printing barcode;
< B> Better security : Not only can be embedded or attached to different shapes, types of products, but also to set cryptographic protection for the read and writing of label data, thereby having higher security;
Dynamic real-time communication : Tags are communicated with the interpreter with 50-00 times per second, so as long as the object attached to the RFID tag occurs within the effective recognition range of the interpreter, Dynamic tracking and monitoring can be performed.