Study And Implement Of High-Pricise Temperature Control System For Temperature Sensor Calibrating

With the development of moden industry and science research, it is higher of the demand of temperature controlling.The measure department needs a temperature control system which should have higher precision, stability, dependability on founding a temperature entironment.The first briefed on temperature measurement methods, characteristics and introduce the Pt100's characteristics. On this basis, design a high-precision temperature control system at the refence of the indicators and the actual requirements.System uses 8051 series MCU(P89C51RD2) as the instrument's controller. And 24 bits AD7710 is chosed as analog to digital convert department. AD7710 has 8 operation modes, by chosing different operation mode, AD7710 can calibration zero-scal and full-scal calibration coefficients. HEF4046 is used to track the electrical frequency. And the change of the AC frequency can't inflect the electric cooker's output.LCD is used as output, provide a good man-to- machine interface.PID control method is used in the control system. The float operation can not be run in P89C51RD2, and the MCU's speed is low. So, using interpolation intead the direct calculate. That's to say, the program spent more code space to get high speed and high precision.Instrument transfers the data to PC by RS-485.The PC software can save all the data on the hard disk.The sofeware also can review the saved data and print out them.