Design Of Sewage Treatment Data Acquisition System Based On CAN Bus

China has the only one fourth of the world's average per capita water capacity, urban sewage treatment is directly related to these limited resources wether they can be used in scientific and rational way, and it also relate to the healthy and stable development of our national economy. With the development of science and modern industry, the automatic and intelligent control has been an inexorable trend. Traditional control systems use PLC as control unit to data acquisition and control from the all equipments. However, data processing capability of PLC is limited, and operating speed is slow, all of these effects refine the developing of system's performance. Using profibus as field bus, with the increasing of the transfer distance, signal rate slowed down, and the timeliness was not well. In order to solve the urgent needs such as timeliness, data transmission speed, data processing capability, a sewage treatment data acquisition system based on CAN bus is designed in this paper,According to the request of sewage treatment system, this paper use PXA270 designed by the Intel as the processor of the main platform, and use LPC2119 chip of 32-bit ARM 7 core as the controller of data acquisition node, based on those, four parts of hardware circuits(digital input and output, analog input and output) were separately designed. Selecting CAN bus to date communication, because of its high reliability, timeliness and flexibility, the system can satisfy the practical needs efficiently. Based on the local control network using ARM7 chip with CAN controller, which made full use of the advantages of 32-bit controller, and realized the network communication of CAN based on ARM, and finished the design of data acquisition system for sewage treatment scene. Through the system test, monitoring system has well timeliness, fast data transmission speed, good data processing capability.