Research And Development Of Field I/O Device Based On EPA

The development of the fieldbus technology leads to several kinds of international standards, but they are incompatible to each other and in consequence, the openness of the fieldbus, the interoperability of the field equipment, and the real-time industrial controlled network cannot be realized. Meanwhile, Industrial Ethernet, with its advantage of mature technology, begins to be applied in the field equipment network, and allows us to see a unified fieldbus standard. In accordance to the tendency, our country establishes the fieldbus national standard based on Ethernet(EPA- Ethernet for Plant Automation), which also gains formal recognition by IEC.The Field I/O Device is an important part of the EPA controlling system, and it is also a very important instrument to acquire, exchange, process, analyze, store and transfer the field signals, and to control the manufacturing process. To research and develop the Field I/O Device based on EPA bears great importance to verifying the EPA bus standards and finally realizing the EPA control system.In this thesis, we study the key techniques concerned in the designing of Field I/O Device. The EPA Communication Stack is a platform to realize the intercommunication of the EPA equipment, and is also the technological core and the designing base to develop the Field I/O Device based on EPA, so after fully comprehending the structure of EPA system, we put forward the module designing idea of the EPA Communication Stack, and realize the communication of the Field I/O Device based on EPA. To enhance the functions of Field I/O Device, we study the powering techniques of Ethernet, and gain two kinds of powering techniques, in-band and out-of-band. Besides, we also make a study and feasibility analysis on the intrinsic safety and anti-explosion techniques of the Field I/O Device based on EPA.Based on the further study and analysis of key techniques, we raise the designing framework of the Field I/O Device based on EPA, and in particular, we demonstrate mechanism and the developing achievement of Standard Signal Acquisition Module based on EPA, such as the hardware, software, function, and communication drive. The hardware development mainly involves developing the communication motherboard and the signal acquiring backboard, while the software development involves acquiring and processing signals, as well as realizing EPA Communication Stack in I/O devices.Besides, to assure the steady operation in industrial field, we accordingly design and analyze the reliability of the module.Till now, the Field I/O Device based on EPA designed by us has passed the precision testing, the EMC(electric- magnetic compatibility) testing, and the EPA communication consistency testing, and has also achieved successful application in the EPA control system of industrial field.