Implementing a Flexible IIoT Service Framework with Microservices: A Case Study of Machine Tools

With the continuous attention given to “smart manufacturing” and “smart factories,” the importance of equipment networking and data collection has been increasing. One key issue is the standardization of equipment networking. Currently, Modbus and OPC/UA are important communication protocols in machine networking. However, software engineers who mainly focus on developing user interfaces and business logic are not proficient in dealing with communication protocols. Therefore, it becomes crucial to enable IT application software engineers to easily interface with various OPC/UA and Modbus machines. Due to the requirements of integration and application of various PLC devices in the machine tool industry, we designed an efficient and flexible IIoT Gateway framework. With the assistance of the IIoT Gateway, IT application engineers developing the ERP/MES systems can easily exchange data (with read and write operations) with various PLC machines. Additionally, to meet the requirements of high performance, the system's functional modules have been designed using multi-threading, asynchronous, and non-blocking techniques. To achieve flexibility in functionality expansion, deployment, high reusing, and low coupling of modules, the Spring Cloud framework has been used to implement microservices and API design for the functional modules. In the future, various system data exchanging and visualization can be facilitated through technologies such as Micrometer/Prometheus, MQTT/Node-RED, and others for convenient logging and tracking.