RFID technology, English for Radio Frequency Identification, Chinese for radio frequency identification, is to identify specific targets by radio signals and read and write related data without identifying the system and specific target 125k~134.2K), high frequency (13.56Mhz), super Radio frequency technology such as high frequency and microwave (2.4-2.5Ghz).
The basic working principle of RFID technology: after the tag enters the magnetic field, it receives the RF signal from the reader, and sends the product information (passive tag, passive tag or passive tag) stored in the chip by the energy obtained by the induced current, or by The tag actively sends a signal of a certain frequency (Active Tag, Active Tag or Active Tag), and the reader reads the information and decodes it, and sends it to the central information system for data processing.
A complete RFID system consists of a reader (Reader) and an electronic tag (TAG) and application software system. The working principle is that the Reader transmits a specific frequency of radio wave energy to the Tag for driving. The Tag circuit sends the internal data, and the Reader receives the interpretation data in order, and sends it to the application for corresponding processing.
There are two broad categories of products derived from RFID technology: passive RFID products and active RFID products.
1.Passive RFID products
Passive RFID products are the earliest developed products and the most mature products in the market. For example, bus cards, canteen meal cards, hotel access cards, second-generation ID cards, parking cards, etc., can be seen everywhere in our daily lives. The main working frequency of its products is low frequency 125KHZ, high frequency 13.56MHZ, ultra high frequency 915MHZ.
A. Low frequency 125KHZ
That is, the frequency band of the commonly known ID card, the reading distance is generally required to be 5-8CM. This frequency band has a wide range of applications, such as canteen meal cards, membership cards, access cards, and so on. Due to its low cost and simple application, it is very popular in some application system software involving RFID. In addition, low-frequency 134Khz injection labels are also common in animal management applications such as dogs and cats.
B. High frequency 13.56MHZ
That is, the frequency band of the commonly known IC card, the read distance is generally required to be 5-8CM. At present, the second-generation ID card used in our country uses the frequency band of 13.56Mhz, and the agreement is 14443B. This frequency band is especially widely used in bus card and library card borrowing applications.
C. Ultra high frequency 915MHZ
This band is more widely used in RFID as 860-960Mhz. The frequency bands used by several major countries and regions are different, such as 902-928Mhz for American Standard, 860-868Mhz for European standard, and 920-925Mhz for our country. At present, the application is based on the American standard, and the center frequency is 915Mhz, so it is collectively referred to as 915. This frequency band is divided into two main protocols, ISO 18000-6B and 6C, of which 6B is the old protocol and 6C is the new protocol. The read distance is generally 0-30 meters, depending on the power of the read/write module, antenna gain, and tag size. UHF 915M has these advantages: Non-contact reading distance (0-30M), multi-tag anti-collision reading, fast recognition, high-speed moving objects, long life, intelligent control, high reliability, etc. Features, currently more and more widely used in IoT applications
2. Active RFID products
Active RFID products have slowly developed in recent years. In the field of remote automatic identification, such as smart prisons, home school and other fields have significant applications. Active RFID has sprung up in this field and belongs to the category of remote automatic identification. The main working frequency of the product is UHF 433MHZ, microwave 2.45GHZ and 5.8GMHZ.
RFID technology applications and solutions
At present, the RFIDs used by our unattended truck scale weighing system are passive RFID products, and the working frequency is 900-960MHZ. The truck scale weighing system can be unattended with the contactless induction card swiping technology. When the car is parked on the weighing platform, the weighing software automatically collects the vehicle information through the RFID device. After weighing the software to judge the weighing data is stable, the photo is captured simultaneously. To save gross or tare, you can use a camera to capture the photo of the driver when swiping, then print the receipt, the vehicle is released, and then start the next car. When a car comes to the tare for the second time, the software automatically calls up the vehicle information. After the software determines that the vehicle is stable, it starts to capture the tare photo, saves the weight, and then combines the data with the first gross weight. Record, calculate the net weight, and then print the document. In this way, the gross weight, tare weight, net weight data of the car, the photos when the gross weight and the tare weight are saved, and the card number of the driver, the card number and the car number are correspondingly stored in the computer, and the car number and the card number on the photo are found to be inconsistent. If the driver's photo is inconsistent, the driver is suspected of cheating. Therefore, the general driver does not dare to change the vehicle to ensure that the weighing weight and the weighing weight are the same vehicle. RFID unattended truck scale weighing system is widely used in power plants, coal mines, non-ferrous metal mines, garbage dumps, cargo terminals and other units.