The Design Of PLC Tooling Test System Based On The Fault Diagnosis

With the continuous development of the electronic information technology and the industry information technology, as an important industrial control equipment, PLC will be increasingly widely-used. In order to fulfill the dream of "Made in China 2025" and deal with more serious informational and industrial security threats, to produce the self-controlled PLC is an important direction of our technological breakthroughs. Because of the various and poor-working environments of PLC, to ensure the reliability and safety of PLC products is not only related to the development of the national economy, but also related to the safety of people's lives and properties. Therefore, the fault analysis of the PLC is of great significance, and the industrial tool test for PLC products is also necessary.The paper is based on the self-control domestic NX Series of PLC products to design the system. According to the structure and functions of the series of PLC, the testing demand for the product was analyzed. At the same time, the testing methods and procedures of each module are proposed and designed. In order to realize better commercialization and higher economic efficiency, the failure mode and effects analysis are applied to the tooling tests in this paper. Fault analysis are made of the NX Series of PLC at the module level based on the failure mode and effects analysis techniques, which lays the foundation for the design of test systems.This paper proposes a more targeted communication protocol between the upper and lower system. The protocol uses a Q&A pattern, which depends on the type of service that the request and response frame structure have different structural characteristics. Considering the authentication security and reducing the cost, it poses a challenge- response authentication mechanism as a security mechanism to improve the security features of the communication protocol. This paper designs the tooling test system software architecture, which is divided into the upper and lower system. In the development process of the upper system in order to achieve the portability and cross-platform, we use the QT software as a development environment. The upper system consists of the main interface, logic processing and communications modules. The main interface module is a UI interface which the testers use. The logic processing module make the logic processing of data communication. And the communications module makes data communication with thelower system. The utilities of multi-threading and buffer technology solve the multi-tasking problems. The lower system contains the loading operation module, the IO management module, the communications module, the auxiliary module and the main tasks module. The main task module is utilized for initialization of each module and data exchange with the communication module. The communication module makes the data transmit to the upper system. The loading and running modules take actions to parse, download and run the projects file. The IO management module manages the input and output between the SCRS and the dual-port RAM of the ERTHERCAT. The auxiliary module is a shared sub-module, which contains the logging module and status display module. Finally, the paper tests the domestic NX Series of PLC with the system. The results show that the software is able to meet the demand.