Factory Equipment Monitoring System Based On 4G And OPC UA

Communication protocols between industrial devices are various and incompatible,which is a common problem in industrial automation industry.Large and medium-sized industrial equipment manufacturers have pushed the communication protocols that conform to their own devices to become market standards,such as EtherCAT,Fins,and MelsecNet.They all have their own characteristics but cannot exchange data directly with each other.With the introduction and implementation of Industry 4.0 and Made in China 2025,the problem of interface uniformity has become a key factor restricting production efficiency.Both the traditional industry and the new industry need a unified protocol specification of interface.Interoperability Unified Standard OPC UA technology is a specification that meets this requirement,which is developed from OPC technology and characterized by wide interface unity,platform independence and high security.Designing a hardware and software system based on the OPC UA specification is of great significance for the monitoring and control of industrial equipment.The paper designs an industrial equipment monitoring system based on 4G and OPC UA.The system selects the network processor MT7628 as the main control chip,and the Quectel technology EC20 as the 4G communication module.On the interface circuit,RS232,RS485,Ethernet port and USB port are designed to connect the field devices,and the hardware is also designed with multiple buttons and LEDs to facilitate human-computer interaction.Linux embedded operating system was transplanted based on this hardware,and the server software conforming to the OPC UA specification was designed using Linux API,which could exchange data with UA client.The paper designed a virtual PLC in the specification of "vendor-specific extension" and "specification of information model specified by other organizations",integrating serial port transparent transmission,virtual private network,USB transparent transmission and firmware upgrade function in virtual PLC protocol.The RUDP protocol is proposed in the stack to reduce delay and packet loss.Industrial data encryption and real-time compression algorithms are also studied.The industrial equipment monitoring system based on 4G and OPC UA runs stably on the Linux operating system and was successfully deployed in the distributed sewage treatment site.The UA client monitors the on-site blower,lift pump,pressure gauge and thermometer status information in real time.4G network solved the problem of inconvenient on-site networking and realizes functions such as remote debugging and downloading of PLC programs.For factories in upgrade,the system can realize the extensive interconnection and interoperability of equipment with lower cost under the premise of keeping the existing basic structure unchanged,including accessing various devices through the UA client,remote debugging and downloading the PLC program and WEB monitoring the state of the plant,etc.,which makes sense for the development of Industry 4.0.