Thermocouple calibration involves the following specific steps:

I. Preparation work

1. Determine the temperature range for calibration: Determine the temperature range that needs to be calibrated according to actual usage requirements.

2. Prepare calibration equipment:

- High-precision temperature sources such as constant temperature baths and tube furnaces that can provide stable and accurate temperatures.

- Digital voltmeters for measuring the electromotive force generated by thermocouples.

- Standard thermocouples with higher precision than the calibrated thermocouple as reference standards.

3. Check the equipment status:

- Check the temperature stability and uniformity of the temperature source to ensure it can maintain stable temperature output throughout the calibration process.

- Check the precision and accuracy of the digital voltmeter and perform necessary calibrations and adjustments.

- Check the appearance of the standard thermocouple and the calibrated thermocouple to ensure there is no damage or defect.

II. Connect equipment

1. Insert the standard thermocouple and the calibrated thermocouple into the temperature source, ensuring the same insertion depth and position to guarantee the same measured temperature.

2. Connect the output terminals of the standard thermocouple and the calibrated thermocouple to the positive and negative poles of the digital voltmeter respectively, paying attention to the correctness and stability of the connection.

III. Conduct calibration

1. Set the temperature of the temperature source: Start from the lowest calibration temperature and gradually increase the temperature at certain intervals until the highest calibration temperature is reached.

2. At each temperature point, after waiting for the temperature source to stabilize, record the electromotive force values of the standard thermocouple and the calibrated thermocouple.

3. According to the electromotive force value of the standard thermocouple and the known temperature-electromotive force relationship, determine the actual temperature at this temperature point.

4. Calculate the error of the calibrated thermocouple at each temperature point: Error = temperature corresponding to the electromotive force of the calibrated thermocouple - actual temperature.

IV. Data analysis and processing

1. Draw a calibration curve: Use temperature as the abscissa and error as the ordinate to draw the calibration curve of the calibrated thermocouple.

2. Analyze the error distribution: Observe the calibration curve and analyze the error distribution to judge the precision and linearity of the calibrated thermocouple.

3. Perform error correction: According to the calibration results, perform error correction on the calibrated thermocouple through software correction or hardware adjustment.

V. Calibration report and records

1. Compile a calibration report: Include contents such as the purpose, scope, equipment, steps, results, and conclusions of the calibration.

2. Record calibration data: Organize the temperature, electromotive force, error and other data recorded during the calibration process into a table and use it as an attachment to the calibration report.

3. Sign and confirm: The calibration personnel and review personnel sign and confirm the calibration report to ensure the accuracy and reliability of the calibration results.

VI. Equipment maintenance and care

1. Clean the equipment: After calibration, clean the temperature source, digital voltmeter, thermocouple and other equipment to remove surface dirt and impurities.

2. Store the equipment: Store the equipment in a dry, ventilated, and light-proof place to avoid being affected by factors such as moisture, high temperature, and magnetic fields.

3. Regular calibration: According to the usage frequency and precision requirements of the equipment, calibrate the calibration equipment regularly to ensure its stable and reliable performance.