Design Of The Resistance Furnace Intelligent Temperature Controller

The resistance furnace is a electric furnace which uses current to makedielectrics or electric heating element generate heat for heating items. It’stemperature is a controlled variable which has the characteristics of time variable,nonlinear, pure time delay and Large inertia, With the development of industry, thetemperature control requirements for all walks of life have become increasingly, Thetraditional analog switch control has not reach the requirements, And low precision,low stability, low level of automation products will gradually be eliminated.Temperature is one of the most basic physical quantities of the provisions of theinternational. For the past few years, Along with the rapid development of scienceand technology, Industrial production put forward higher request to theperformance of the products. And the heat treatment of production process is acritical segment for improving product performance. So, it has big realisticsignificance and use value of the studies of resistance furnace’s temperature measureand control. Based on the above, In the paper, I designed a intelligent temperature controllerof resistance furnace based on STM32single-chip microcomputer. The temperaturecontroller hardware circuit using STM32f103MCU, K type thermocouple, K typethermocouple converter MAX6675, solid state relays and other major components,Software programming using C language and Keil uVision4ARM system softwarecompiler, Could measure and control the temperature from0℃to1023.75℃. Inthe design, Using K type thermocouple as the temperature sensing elementm, todetect the temperature of resistance furnace and output millivolt level analog voltagesignal, sent the signal to the K type thermocouple converter MAX6675for coldjunction compensation, amplification, linearization and digital processing, and get theresistance furnace temperature in digital form for its use in the STM32MCU, In thecontrol execution circuit use solid state relay SSR in order to use zero-crossingtrigger control conduction or disconnect of the main circuit of the resistancefurnace,Last, achieve control and adjustment the resistance furnace temperature.For the design uses a highly integrated high-performance digital-typetemperature conditioning component of MAX6675, whose Internal integration havein the measurement of the signal type K thermocouple linear circuit and amplifier,digital circuit. So it makes easy to design the circuit, But measurement accuracy, stable performance, strong anti-interference ability. In addition, The control elementsuses solid state relay replace the traditional electromagnetic relays, for the solid staterelay’s contactless, clean break and fast take on or off the circuit, The intelligenttemperature controller of resistance furnace will has high control precision.