Research On The Manipulative Technique Of Temperature Control System With The Delay Time Feature

Temperature is the international system of Units(SI),one of seven fundamental physical quantity, almost all of research and production process is closely related to it, and temperature control system is widely using in steel and electron and metallurgy and machine and industry in our country . It has the feature of pure time delay and great inertia and variety of parameter etc, so it need high quality temperature controller. At present, most of enterprise is making use of drying furnace that it controlling precision is low and temperature in furnace is not uniformity .It do not fixit the request of technical .So the price of using is high and effect benefit of enterprise .It need alteration.In recent years, people research temperature controller deeply .Along with the development of computer technology, temperature controller have made a great progress and development, and appears some commercial temperature controller. For example: intelligentize PID and fuzzy control and self-adaptive control etc.Based on the time delay of temperature problems, because of limited space, in this paper the theoretics were explained only from analog PID control, digital PID control, intelligent PID control and Smith control. Especially, in the analog PID control system and digital PID control system, they focused on effective control method and parameter tuning method, and mend integral and differential coefficient, conquered the differential and integral saturation in PID control system, and increased the control precision. And undergraduate teaching of temperature control experiment delay for the design, assembly and experiment. The experiment approved that the time delay of temperature control system can reach the experimental regulation, and it can obtain higher precision in experiment.The time delay of temperature control experiment has several parts: one to collect temperature, one to compute, one to heating and one to display temperature. The part of the core in the time delay of temperature control experiment included simulative PID control system and SCM PID control system. Students can make use of these two different experimental testing of the control system, thus the automatic control system to a more profound understanding of them.The collect temperature is achieved through by Pt100 temperature thermal resistance. Considered the trait of Pt100 temperature thermal resistance, the temperature signal acquisition put into voltage signals, after this weak signal voltage amplifier temperature control signals are amplified and transmitted to the main part.Based on some special requirements of experiment, the main control system is separated into PID control system simulation and SCM PID control system. PID control system simulation is that measurements (acquisition part of the transmission voltage temperature) compared with the value set for the error ratio (P), integral (I) and differential (D) operational amplifier. Based on the specific regulatory parameters specific regulatory requirements, the main control system is the depth of negative feedback closed loop control devices. The characteristics have flexible operating, high-precision control and so on. On the other hand, SCM PID control system is one of the digital PID control, which is run by SCM program. The PID closed-loop control system simulation and control principle is roughly similar, but they realize in the different ways. In the SCM PID control system, the error that measurements (acquisition part of the transmission voltage temperature) compared with the value set, passed ADC through analog signal into digital signals and transmitted to the MCU. Based on SCM`s calculation procedure, the result are sent to the DAC converter, and switch the result to analog signals, which transmitted the heating. The characteristic have high control accuracy and high degree of automation, but the parameters of P, I and D can not be arbitrarily changed. Using the PID control , the temperature can be controlled within the range of 50～500℃with a precision of±3℃and uninterrupted adjustability of temperature setting is realized .The heating include booster and heating furnace. Booster`s function is transform the 0-5 volt d. c coming from the main control part system to 0-220 alternating current. After booster, the alternating current transmitted to the heating furnace to heat up, and the raise temperature that measured by Pt100 temperature thermal resistance transmitted to the temperature acquisition. In this way, the control system running go round and round, formed a well-knit closed-loop control system.The temperature display will receive and treat data, which track number tube to show real temperature, showing set temperature, feedback control temperature and the output voltage from the main control part system.The time delay temperature control system have several traits as follows:1. High degree automatization.2. Advanced hardware technology, and design in reason. 3. The blocking frame was adopt by system.4. High degree standardization.5.The high precision temperature control.