Intelligent Pressure Transmitter Based On CAN Fieldbus Technology

With the development of the fieldbus technology, the traditional control system steps into FCS (Fieldbus Control System), the integrated and distributed control system. The spread and popularity of FCS bring forward new requirements for the measuring and transmitting instruments. The new generation of fieldbus instrument should not only have the fundamental measurement capability, but also can communicate with the supervisory computer and fieldbus instruments. Otherwise it should also have the control capability.In order to meet with requirements of fieldbus instruments, a intelligent pressure transmitter based on CAN fieldbus technology is developed. It is exploited using MOTOROLA products, MPX5000 series pressure sensor and 68HCS12 series microcontroller with CAN interface. The thesis introduces the works for the instrument development, and its major contents include the following parts. The first part is about CAN fieldbus, including its feature, technical specification, protocol, device and application. The second part is about the hardware design, including the microcontroller module, the sensor module, the LCD module, the communication module, the power module and the anti-jamming measures. The third part is about the software design, including the program of initialization, data acquisition, data processing, LCD, control, communication and system testing. The fourth part is about experimentation and data analysis. It comes to the conclusion that the instrument conforms to the requirements of fieldbus intelligent appliances. The last part is about the conclusion of the paper and a prospect about the improvement and perfection of the instrument.