RFID stands for Radio Frequency Identification . It uses radio frequency to enable data transmission between a programmable logic controller (PLC) or microcomputer (PC) and the tag , thereby achieving non-contact target identification and tracking.
A typical RFID radio frequency identification system consists of four parts: tag, antenna, controller and host (PLC or PC), and the system structure diagram is shown in Figure 1.
Tags are typically fixed to the object being tracked and identified, such as pallets, shelves, carts, and containers. They can store a certain number of bytes of data to record important information about the object. When the tag moves with the object, it becomes a mobile data carrier. For example, in the application of RFID on computer assembly lines, the tag can record the type of chassis (vertical or horizontal), required components and models (motherboard, hard drive, CD-ROM, etc.), and the processes to be completed. Similarly, in the automatic sorting and tracking of mail packages, the tag can store information such as the package's origin, destination, and route.
The function of an antenna is to read data from or write data to a sign using radio electromagnetic waves. Antennas come in various shapes and sizes, ranging from large enough to be used as doors or passageways at warehouse exits to as small as 1mm.
The controller is used to control data communication between the antenna and the PLC or PC. Some controllers also have digital input/output functions and can be used directly for control. The controller and antenna together are called a reader/writer.
The PLC or PC performs corresponding process control, or performs data analysis, display, and storage based on the data captured by the reader/writer from the identifier.
This article takes the LRP830 13.56MHz passive RFID reader from EMS (Escort Memory Systems) in the United States as an example to introduce the specific implementation method of serial communication between PLC and PC and RFID reader to obtain identification data for control or data processing.
