Research And Design Of Intelligent Temperature Transmitter Based On The Fieldbus Network

Coupled with the continuous development of the technology of intelligentization and cyberization in industrial automation system, the fieldbus technology has made great progress in recent years. The fieldbus products have played a significant role in the market for their consummate functions and extrusive characteristics. So it is certain that the fieldbus temperature transmitter should take place of the traditional temperature transmitter. Therefore, the research and design of the fieldbus smart temperature transmitter is of great value.The project applied PROFIBUS communications protocol to a design of temperature transmitter, which can not only convert temperature variable into standardized output signal to measure the temperature parameter in industry, but also be connected to the PROFIBUS fieldbus control system as a slave station with its DP communication interface to communicate with the master station based on PROFIBUS fieldbus protocol. And at the same time the master station can carry on the real-time remote monitoring, calibration and configuration on the temperature transmitter to ensure a safe, reliable, stable operation of the system. On selecting the system design scheme, different from the traditional smart temperature transmitter based on MCU, this thesis adopts SOPC technology based on the Nios II and mainly discussed in detail three aspects of the overall design framework, hardware system and software system of the project. Firstly the thesis introduces the composition and operational principle of temperature transmitter and the system development process. Then the system control scheme is selected, which includes the selection of microcontroller chip FPGA, the application of SOPC technology and the construction of Nios II system. Besides the fieldbus technology are briefly introduced and the framework of intelligent temperature transmitter is designed. On the system hardware, it mainly includes the design of temperature collection module, analog quantity output module, LCD display module, communicating module, storage system module, program downloading module, etc. On the system software, it mainly includes the system main program, temperature collection subroutine, LCD display subroutine, communication subroutine, device descriptions program, etc.Finally, the fieldbus temperature transmitter has been tested overall through the experiment platform. On the one hand it meets the accuracy requirements according to the analysis of temperature acquisition information. And on the other, according to the analysis of test communication messages, it realizes the PROFIBUS-DP protocol, including inquiring slave station state, system configuration, fault diagnosis, data transmission and switching. It can be concluded that the design of the temperature transmitter reaches the anticipative goal.