The Research Of The Anti-Surge Control System Based On CAN Bus For Centrifugal Compressor

This thesis proposal the research of the anti-surge control system for centrifugal compressor based on the fieldbus technology. Surge phenomenon, which is the inherent characteristic of centrifugal compressor, is defined as the instability flow condition when centrifugal compressors works in little flow, and does great harm to industrial production. As one of the develop focuses in the field of automatization today, fieldbus is an open, digital and multi-node communications network in the bottom. It carries out bi-directional and multi-node in serials digital communication between monitoring and control equipments of microcomputers in Production site. Hence, a new distribution control system in the manner of integrated network called FCS (Fieldbus control system) has been developed. Its advantage is the characteristic of openness and interchangeability, simple network frame, reducing production costs and decrease of maintenance.This thesis has chosen a kind of fieldbus, which suits the application of practical project --CAN bus on the base of analysis and comparison with the influential fieldbus today, and DeviceNet as the communication standard, then makes brief research to characteristics. This thesis divides anti-surge control system for centrifugal compressor into two parts: the field gathering note and the control system in epigynous computer. The central parts of the field gathering note are the P8xC59 single-chip 8-bit microcontroller with CAN controller, the TJA1050 high speed CAN transceiver and the analog-to-digital converter AD676. It also takes a deep discuss and detailed dissertation to the function modules'composing , principle of work, hardware design, software design, and their realization method of the gathering node. Also, realizing CAN message communication based on DeviceNet in the communication module design. The control system in epigynous computer based on MCGS achieves data gathering, real-time and historical data processing, alarm and safety, flow control, animation display, the trend curve, statistics export and network monitor functions, and so on. It takes use of PCI-5121 CAN bus intelligential control card to achieve the data communication between CAN bus and epigynous computer, OPC server ZOPC_Server realizing the communication between CAN control card and MCGS , in order to strengthen the versatility and flexibility of system.It is proved that the system can prevent the happening of the surge phenomenon, and the circulation flow of the compressor is automatically adjusted according to the work state's change. On the condition of avoiding surge, the circulation flow is depressed to the lowest. It has friendly interface, fine design, clear and exact work point. So the whole design fulfils the anticipated function requirements and well embodies the characteristic and the superiority of fieldbus.