The Design And Implementation Of RFID Integrated Machine Network Based On MODBUS Protocol

RFID technology is a hot topic in today’s society, which has been widely used in all areas of society. It has also brought convenience to people’s life. With UHF RFID technology growing more and more ultra-high frequency products emerge. At the same time, the control system driven by the fieldbus and industrial Ethernet technology development has undergone fundamental changes. Distributed network control system will become the mainstream.This thesis researches the use of UHF RFID reader machine in industrial automation application scenario, which focuses on exploring the application of the MODBUS protocol on read-write integrated machine, and then designes a complete set of effective network control systems. The main content is as follows:1. This thesis researches MODBUS serial link protocol and MODBUS TCP protocol. Then designes a complete MODBUS protocol stack and makes the read-write integrated machine work well on the stack architecture according to the characteristics of existing MODBUS protocol and RFID read-write integrated machine application.2. This thesis designes and implements MODBUS serial link host and slave program. Master and slave can half-duplex communicate via RS485 interface, host can unified control all the slaves on serial link. On the design of slave, the realization of RFID read-write integrated machine and MODBUS protocol should be fully taken into account. On the design of a simple-to-use protocol stack we should notice the combination of both parts. On the design of host, we should set aside the upper application interface, the upper application should have characteristics like easy to use and feature-rich.3. This thesis designes and implements MODBUS gateway and MODBUS TCP host program. Devices on the serial link can communicate with devices on Industrial Ethernet by the gateway, which had weaken the limitations of the communication link. Due to the difference between a serial communication link protocol and Ethernet protocols, gateway should be designed to be compatible with two protocols. The conversion of protocols and the buffer should be considered. Via MODBUS TCP host program, user can communicate with the MODBUS TCP slave. In this thesis MODBUS gateway allows the host program communicate with read-write integrated machine on serial link.The entire reader control system based on MODBUS serial link protocol and MODBUS TCP protocol was tested in the laboratory environment. The test result shows that read-write integrated machine functiones properly. It can properly do tag reading and writing operations. MODBUS protocol stack also functiones well. The interaction between master and slave is good, and the anomaly can be notified to the user by packets. Users can directly control read-write integrated machine by host on serial link, it can also be controlled by MODBUS TCP host via gateway in Ethernet environments.