Automatic Control System Based On Fieldbus For Swage Treatment

Field bus technology is a digital, distributed, open and inter-operational technology, which represents the development trend of industrial control system. It is one of the technology what has attracted more attention in the field of automatic control. In this paper, according to the factual case of city sewage treatment plant, we analyzed and designed an automatic control system for swage treatment what is based on field bus technology.At first, in this paper, we detailed discussed the field bus control system in theory, introduced the concept of field bus, the structure of network, communication model and five representative field bus. We emphasized on the detail of PROFIBUS field bus. And then, consider the actual control requirement in a sewage work, this paper compares and analyzes several industry network patterns such as DCS, field bus, industrial Ethernet in a integrated automatic system's integrality, reliability, extendibility and open capability, and brings forward a communication network scheme, which is based on PROFIBUS field bus. According to the city swage treatment process, we put forward the integrated plan and execution particular for the swage treatment automatic control system.In addition, there are many difficulties in the process of swage treatment, such as continuous working, the variable is hard to be online measured, non-linearity, intermittence, delay and more disturbers. In this paper we research into the process of aeration tank control. We compare the results of respectively applying PID and fuzzy strategy using of MATLAB emulation toolbox. The fuzzy strategy gets a good result, and it needn't a correct math model, so it is chose and implemented in PLC through a table look-up program.Lastly, this paper prospected the foreground of field bus in the industry control field.