A High Precision Platinum Resistance Temperature Regulator

In our country, the automation level of some beer enterprises is rather low, so resulting in low productivity and quality, high energy resources consumption. Beer ferment is one of the most important working procedures in beer production and the most critical step to ensure beer quality. According to working procedure, the producing period usually is about 15 days, the temperature of ferment liquids should vary in accordance with regular working procedure curves.The temperature control precision should be within the scope ±0.5℃ .If we use the traditional heat technological instruments and manual operation method could not satisfy the demand. In order to get better result for beer quality and production the temperature controller for beer ferment process is developed. Nowadays this system adopts comparatively advanced 51 series micro - processor with outside interface component. This controller has the characteristic of simple structure and high reliability and low investment. It is one of the best plans to enhance producing level and beer quality for small and medium enterprises.In order to satisfy the requirement of working procedure for the temperature control precision, two problems must be resolved: the first, the temperature measurement precision should be high, second, the temperature control precision is also high. For enhancing the precision of temperature measurement, the article putting forward how to eliminate the affect for conducting wire resistance of thermal resistance varying with environment temperature, zero-point drift of amplifier, change of amplifier magnifying multiple to temperature measurement. As for temperature control to the ferment tank in beer working procedure, the time constant is a little large and it is controlled at regular time-temperature curves, using normal PID regulating method could not reach the requirement for the ideal temperature control precision. So fuzzy control method is adopted. In normal fuzzy controller, it usually adopted two-dimensional space regular PD controller. Using the fuzzy controlling system, it is possible to get better result of dynamic characteristic, but the static characteristic could not be satisfied.To get higher stable precision, the structure of fuzzy controller is improved and integral affect is introduced.By means of actual production, each index of the controller reaches the designing standard; satisfy the requirement of the temperature control precision for working procedure.