Application Of DCS System On Bio-reactor

According to different parameters' characteristic, applying DCS system to control small-sized bio-reactors with different control-algorithms, such as PID calculation method, time-scale calculation method and Fuzzy PID calculation method. The parameters are temperature, pressure, flux, oxygen-solution, pH value, material-supplement and foam. It includes sensors, field instruments, microcomputers, up computers, communication interface and executor.Down computer's core is AT89C52. It adopts a big LCD screen which displays Chinese characters. It includes A/D, D/A, SSR output and keyboard. It's main function include data's collection , adjustment and field display, keyboard's enactment and saving of control parameter, analog and digital output, the real time communication with up computer, data's saving, the inquiring of history data, sound and light alarm of upper and lower limit and abnormity. Down computer can control all parameters without up computer.Up computer is common PC. It uses DELPHI5.0 as the development platform and OOP(object-oriented programming) technology, and has a good user interface, and operation is visual and safe. Adopting DCS of point to point to carry out one up computer to communicate with 32 down computers as the same time and long-distance real-time control. Up computer's main function include data's real-time abnormity, display, analysis and printing, history data's curve display and abnormity, control parameter's enactment, parameter's curve simulating control, on-line real time detection, real time curve' trend display, real time display of all executors, communication with down computer, configuration of down computers' user program, password management, sound alarm.Communication system use RS485 field bus and can transport data quickly for long-distance so that up computer can communicate with down computers.By testing two GY10C fermentations, all kinds of performance figures reach design requirement. According to the testing, we also optimize the system so that it becomes more dependable.