Thermocouple calibration is an important process to ensure the accuracy of its temperature measurements. Here are the detailed calibration steps:
1. Preparation: Connect the circuit of the thermometer according to the calibration schematic diagram of the thermocouple thermometer, and then put the thermocouple thermometer into the thermostat to make the temperature measurement part of the thermometer reach the same plane as the water surface.
2. Temperature regulation and recording: Adjust the temperature in the thermostat and then record the thermocouple thermometer readings after the temperature adjustment. At the same time, the temperature reading of the corresponding thermocouple thermometer is read from the microcomputer display.
3. Repeat the measurement: repeat the first and second steps above several times, at least 4 times.
4. Calculate the error range: Use the temperature formula and linear regression equation of the thermocouple thermometer to calculate the difference between its measured value and the average value according to the value obtained by the thermocouple thermometer after each calibration, that is, calculate its error range.
5. Standard comparison: The comparison method is generally adopted, that is, compared with the standard, so as to obtain the difference. The K-type couple is usually calibrated by the bipolar comparison method, which is to use the standard high-grade platinum-rhodium-platinum thermocouple and the K-type to measure the potential MV value and the value of the platinum-rhodium-platinum thermocouple when they are heated to a certain temperature together in the furnace to compare and compare the value of the platinum-rhodium platinum thermocouple, and to see whether the K-type couple is qualified by calculation.
6. Instrument adjustment: In addition to the self-correction ability of the zero, linear and temperature drift of the thermocouple's instrument, it can be adjusted at any time by reading the manual and through the keyboard.
7. Self-tuning function: Some thermocouples have self-tuning function, which can be tuned after a period of use to improve accuracy. Remember, set the temperature at a stable temperature.
8. Calibration result processing: calibrate the qualified thermocouple, fill in the calibration data in the calibration table of the measuring instrument, and attach the calibration qualified label to the thermocouple. Calibrate unqualified thermocouples, adjust and repair them before calibration, and if they are not qualified, they will be scrapped and labeled as unqualified.
9. Calibration cycle: The calibration cycle of thermocouples is generally not more than one year.
With the above methods, thermocouples can be effectively calibrated to ensure the accuracy and reliability of their measurement results.