Introduction to the operating environment and interface mode of the radio frequency identification application system
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RFID technology is a key technology for the development of the Internet of Things, and its application market will inevitably expand with the development of the Internet of Things. This article mainly introduces the operating environment and interface methods of the radio frequency identification application system in detail. Follow the editor to learn more about it.
Introduction to RFID Application System
RFID radio frequency identification is a non-contact automatic identification technology, which automatically recognizes the target object and obtains relevant data through radio frequency signals. The identification work does not require manual intervention and can work in various harsh environments. RFID technology can identify high-speed moving objects and can identify multiple tags at the same time, and the operation is quick and convenient.
Short-distance radio frequency products are not afraid of harsh environments such as oil stains and dust pollution. They can replace barcodes in such environments, for example, to track objects on the assembly line of a factory. Long-distance radio frequency products are mostly used in traffic, and the identification distance can reach tens of meters, such as automatic toll collection or vehicle identification.
Application of RFID technology
1. In the retail industry, the use of barcode technology has enabled tens of thousands of commodity types, prices, origins, batches, shelves, inventory, etc.
2. The use of automatic vehicle identification technology enables roads, bridges, parking lots and other toll places to avoid the phenomenon of vehicles queuing for customs clearance, reducing time waste, thereby greatly improving the efficiency of transportation and the capacity of transportation facilities;
3. In the automated production line, all links of the entire product production process are placed under strict monitoring and management;
4. In harsh environments such as dust, pollution, cold, and heat, the use of long-distance radio frequency identification technology has improved the inconvenience of truck drivers having to get out of the car to go through procedures;
5. In the operation and management of the bus, the automatic identification system accurately records the arrival and departure time of the vehicle at each station along the line, and provides real-time and reliable information for vehicle scheduling and overall operation management.
Operating environment of radio frequency identification application system
A complete radio frequency identification application system should include readers, electronic tags, computer networks and other equipment. Considering the issues of data reading, processing, and transmission, the installation of the reader’s antenna and the distance of the transmission distance should also be considered.
The operating environment of RFID technology is relatively loose. From the operating environment of the application software system, any software based on any programming language can be run on any existing system.
Computer platform systems include Windows, Linux, UNIX and DOS platform systems.
Interface mode of radio frequency identification application system
(1) RJ45
RF45 and Category 5 cables are used in conjunction with Ethernet networks. The 8 lines are divided into 4 groups, which are composed of 8 single-color or white-colored lines of red and white, red, green and white, green, blue and white, blue, brown and white, and brown. There are two connection methods for RJ45, namely T-568A and T-568B. The only difference between the two connection methods is the wire sequence.
RJ45 transmits the signal far away and uses the TCP/IP protocol.
(2) RS-232
RS-232 is a popular computer serial interface. Commonly used RS-232 interface has two forms: DB9 and DB25.
RS-232 is a wide-ranging serial transmission interface developed by the Federation of Electronic Industries to connect data terminal equipment to data communication equipment. RS-232 specifies the type of wire and connector, the connection method of the connector, and the function, voltage, meaning and control process of each wire. RS-232 is compatible with ITU’s V.24 and V.28.
(3)rs-485/’ target=”_blank”>RS-485/ RS-422
RS-422 is a full-duplex interface that uses a smooth line, which has stronger anti-interference ability than RS-232. When other conditions of RS-422 data transmission speed are the same, the identification distance of the low-frequency system is the shortest, followed by the medium-high frequency system and the microwave system, and the identification distance of the microwave system is the longest. As long as the frequency of the reader changes, the operating frequency of the system will change accordingly.
The effective recognition distance of the radio frequency identification system is proportional to the radio frequency emission power of the reader. The greater the transmission power, the greater the recognition distance. However, when the radiation generated by electromagnetic waves exceeds a certain range, it will have harmful effects on the environment and the human body. Therefore, certain power standards must be followed in terms of electromagnetic power.
The packaging form of the electronic label is also one of the reasons that affects the recognition distance of the system. The larger the antenna of the electronic tag, that is, the greater the magnetic flux obtained by the electronic tag passing through the active area of the reader, and the greater the stored energy.
The operating distance required by the application project depends on many factors: the positioning accuracy of the electronic tag; the minimum distance between multiple electronic tags in actual applications; the moving speed of the electronic tag in the working area of the reader.
Generally, in RFID applications, selecting the appropriate antenna can meet the needs of long-distance reading and writing. For example, the FastTrack conveyor belt antenna is designed to be installed on the conveyor belt between the rollers, and the REID carrier is installed on the bottom of the tray or product to ensure that the carrier passes directly through the antenna.
(3) Data transmission rate
For most data acquisition systems, speed is a very important factor. Due to the continuous shortening of product production cycles today, the time required to read and update RFID carriers is getting shorter and shorter.
① Read-only rate
The data transmission rate of the RFID read-only system depends on factors such as the length of the code, the data transmission rate of the carrier, the reading and writing distance, the carrier frequency between the carrier and the antenna, and the modulation technology of the data transmission. The transmission rate varies with the types of products in actual applications.
②Passive read and write rate
The determinants of the data transmission rate of the passive read-write REID system are the same as that of the read-only system, but in addition to reading data from the carrier, it is also necessary to consider writing data to the carrier. The transmission rate varies with the types of products in actual applications.
③Active reading and writing rate
The determinants of the data transmission rate of an active read-write RFID system are the same as those of a passive system. The difference is that the passive system needs to activate the capacitor charging on the carrier to communicate. A very important point is that the operating rate of a typical low-frequency read-write system may only be 100 bytes/s or 200 bytes/s. In this way, because there may be hundreds of bytes of data to be transmitted on a site, the data transmission time will take several seconds, which may be longer than the entire mechanical operation. EMS company has adopted several unique and proprietary technologies to design a low-frequency system with a higher speed than most microwave systems.
(4) Safety requirements
Security requirements generally refer to encryption and identity authentication. A very accurate assessment of the security requirements of a planned radio frequency identification system should be made in order to rule out various dangerous attacks that may appear in the application phase from the beginning. To this end, it is necessary to analyze the various security vulnerabilities in the system and the possibility of attacks.
(5) Storage capacity
The storage capacity of the data carrier is different, and the price of the system is also different. The price of the data carrier is mainly determined by the storage capacity of the electronic tag.
For applications that are price-sensitive and have little on-site demand, a fixed-code read-only data carrier should be used. If you want to write information into the electronic tag, you need to use the electronic tag of EEPROM or RAM storage technology, and the system cost will increase.
A basic rule of memory-based systems is that the storage capacity is always insufficient. There is no doubt that expanding the storage capacity of the system will naturally expand the field of application. The storage capacity of the read-only carrier is 20 bits, and the storage capacity of the active read-write carrier ranges from 64B to 32KB, which means that several pages of text can be stored in the read-write carrier, which is enough to load the manifest and test data , And allow system expansion. The storage space of the passive read-write carrier ranges from 48B to 736B, and it has many characteristics that the active read-write system does not have.
(6) Connectivity of RFID system
As the development branch of automation systems, RFID technology must be able to integrate existing and developing automation technologies. It is important that the REID system can be directly connected to a personal computer, programmable logic controller or industrial network interface module (field bus), thereby reducing installation costs. Connectivity enables RFID technology to provide flexible functions and easy integration into a wide range of industrial applications.
(7) Simultaneous readability of multiple electronic tags
Since the system may need to recognize multiple electronic tags at the same time, the readability of multiple tags provided by the reader also needs to be considered. This is related to the reading performance of the reader and the moving speed of the electronic tag.
(8) Packaging form of electronic label
For different working environments, the size and form of the electronic label determine the installation and performance of the electronic label, and the packaging form of the electronic label is also one of the parameters that need to be considered. The packaging form of the electronic label not only affects the working performance of the system, but also affects the safety performance and aesthetics of the system.
The evaluation of the performance indicators of the radio frequency identification system is very complicated. There are many factors that affect the overall performance of the radio frequency identification system, including product factors, market factors, and environmental factors.
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