Temperature Control Technology And Its Application And Research In The Digester

When the biological and chemical composition of surface water or sewage measured, need to be heaten carrying on certain time in a certainly regular temperature,under the process of certain chemical reagent, thus the accurate metrical result could be obtained. Accuracy and stability of the pyrogenation and the precision of temperature control influences the test result directly.Applications for this background, this thesis is about discussion and research of special-purpose on heating tested reagent equipment (Digester)'s temperature control system.This Thesis is on the introduction about digester's temperature-controled systematic principle and many kinds of temperature-controled tactics basis on the PID technology. It has discussed Classical PID, Digital PID, Dahlin and Smith control algorithms and expert intellectual PID system's application in the temperature control, and has offered a kind method of constructing the temperature-controled systematic, and analyses the hardware of this system and software of design plan in detail.Digester's systematic hardware is the circuit of taking PWM and solid state relay as the core, including input / output circuit, current / voltage changed circuit, circuit of the expansive memory, liquid crystal circuit, circuit of the temperature measure and hardware PID control circuit made up of RC, amplifier etc..The temperature-controled systems software is written by C language including data gathered, data analysed and processed, clock simulation and software procedures of the liquid crystal display.The experiments of different PID control strategy has been done, relevant experimental data has got. Through comparing the real effect of every algorithm, find out that useing expert system PID - It is best to utilize the knowledge base of expert system to output result that revises PID parameter online, compared with the routine control strategy, exceed adjusting amount to reduce by 95%, regulate time to shorten by 50%, precision is under 0.5 degrees Centigrade. It find a feasible settlement way by this Method for being non-linear heavy lagging behind and control that at the parameter, improve precision, speediness and stability of temperature control, it reachs the desirable performance of digester.