Research On Temperature Calibration System And Calibration Method

Temperature measurement has penetrated into many aspects of daily life and national economy, in order to improve the measurement precision and make contributions to the national economy; it is very important and significant to research the temperature calibration system and calibration method.In order to make the accuracy of the temperature calibration system higher than the temperature measurement system for calibration, though the study on temperature calibration methods, this paper design a temperature calibration system, which consists of temperature detection module, controlling module, adjusting module, heating module and displaying module, the core modules are the high precision temperature measurement module and controlling module.In order to prevent the influence resulted from self-heating of the circuit, ensure the intensity of the signal-to-noise ratio, this paper adopts REF200to provide a0.4mA high precision constant current to drive four wire circuit platinum resistor sensor PT1000, then the measurement module of the calibration system is developed, and the leading errors introduced by the platinum resistance can be eliminated effectively.In order to overcome the shortcomings such as big volume, long settling time of water-and oil bath incubator commonly used in laboratory, the temperature controlling module of the calibration system uses fuzzy PID algorithm to adjust and control the temperature, and the temperature controlling system can achieve a stabile condition via setting up the reasonable controlling parameters. Heating module selects the PWM way as the direct current heating control method for the furnace body to provide a constant temperature field to the standard sensor and the sensor for calibration.Tests for temperature measurement module and constant temperature controlling module of this proposed calibration system are conducted, and the tests results show that in the range of0-50℃, the measurement error is less than0.06℃, and the temperature controlling error is less than0.08℃, which achieves the accuracy requirements of the temperature measurement instruments for calibration.