Thermocouple cold-end thermostat device for portable field calibration and control method thereof

Abstract

The invention relates to a thermocouple cold-end thermostat device for portable field calibration and a control method thereof, and belongs to the technical field of thermocouple cold-end constant temperature control. The thermocouple cold-end thermostat device includes a 0-degree-centigrade thermostat and a control system. The 0-degree-centigrade thermostat includes a temperature equalizer, a semiconductor cooler, a thermistor and a semiconductor cooler radiator-cooler. The control system comprises four thermistor temperature sensors, a conditioning circuit, a microcontroller, four TEC driving circuits, a keyboard circuit, an LCD display circuit and a ZigBee module. The thermocouple cold-end thermostat method sets eight modes for the operation of the semiconductor cooler. The control system has high temperature uniformity and stability, completely meets the temperature field requirements of a thermocouple calibration reference-end thermostat, and is small in size, easy to carry, and suitable for field calibration because of the temperature equalizer and modular design,.

Description

technical field [0001] The invention belongs to the technical field of thermocouple cold-end constant temperature control, and relates to a portable field calibration thermocouple cold-end constant temperature device and a control method thereof. Background technique [0002] The current popular semiconductor zero-degree automatic constant temperature adopts a structure in which the cold end of the thermocouple is directly inserted into the 0°C temperature field. This device has the following disadvantages: the hot end of the semiconductor refrigerator adopts a water cooling method, which is inconvenient to use; the conventional PID control mode of the analog circuit is used to control the silicon controlled rectifier to adjust the working current of the semiconductor refrigerator, and the conventional PID control method implemented by hardware PID control, its proportional coefficient, differential time and integral time constant are fixed, it is difficult to obtain the bes...

AI Technical Summary

Problems solved by technology

This device has the following disadvantages: the hot end of the semiconductor refrigerator adopts a water cooling method, which is inconvenient to use; the conventional PID control mode of the analog circuit is used to control the silicon controlled rectifier to adjust the working current of the semiconductor refrigerator, and the conventional PID control method implemented by hardware PID control, its proportional coefficient, differential time and integral time constant are fixed, it is difficult to obtain the best control quality; measuring the natural aging of the bridge resistance element, its parameters will drift with time, and the controlled temperature will have a certain fluctuation after long-term use Deviation Affects Check Accuracy

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