What are the specific steps for self-calibrating a K-type thermocouple probe?

I. Preparation and Safety Confirmation Before Calibration Tool Verification: Confirm that you have a contact-type standard thermometer with an accuracy of ±0.1℃, a 0.01-grade digital multimeter, a 0.01mm digital vernier caliper, high-temperature resistant gloves, and a backup USB flash drive. All measuring tools are within their expiration dates. Status Confirmation: The probe extension length is stable at 2~3mm, the temperature sensing contact is completely in contact with the bottom of the temperature sensing hole, the insulation resistance is ≥5MΩ, there are no flammable or explosive materials around the hot runner, and the power is off and the temperature is allowed to cool to room temperature before starting the operation. Parameter Backup: Access the Husky temperature controller's "System Settings - Calibration Parameter Export" page and export the original calibration parameters for all current channels to the USB flash drive to avoid accidentally overwriting the original factory settings. II. Pre-calibration Troubleshooting: Use a multimeter to measure the thermocouple's thermoelectric potential and loop resistance channel by channel. Compare with the standard parameters for a type K thermocouple to confirm the probe is free from green corrosion, broken wires, and oxidation/deterioration of the thermocouple wires. Replace any unqualified probes before recalibrating. Clean any residual carbon deposits and old silicone grease from the exposed sections of the probe. Confirm the ceramic insulation sleeve is undamaged and the cold junction heat conduction path is completely blocked to avoid residual effects affecting calibration accuracy. III. Three-Point Full-Condition Core Calibration: 100℃ Low-Temperature Calibration: Set the temperature controller to 100℃, start heating and maintain the temperature for 1 hour. After the temperature has completely stabilized, use a standard thermometer to measure the actual temperature at the corresponding measuring point. Enter this measured value into the Husky temperature controller's "Low-Temperature Calibration" menu to complete the first-point calibration. 200℃ Mid-Temperature Calibration: Raise the set temperature to 200℃, hold for 1.5 hours until the temperature is uniform and stable, then measure the actual temperature at the measurement point again using a standard thermometer. Enter the measured value in the "Mid-Temperature Calibration" menu to complete the second calibration. 300℃ High-Temperature Calibration: Raise the set temperature to the rated maximum operating temperature of the hot runner (typically 300℃), hold for 2 hours until the temperature is completely stable, measure the actual temperature, and enter the value in the "High-Temperature Calibration" menu to complete the third calibration. IV. Cold Junction Compensation Specific Adjustment: Measure the actual ambient temperature at the temperature controller's terminals using a thermometer. Set this value as the cold junction reference temperature of the temperature controller to offset the systematic negative deviation caused by the cold junction thermal conductivity effect. For the current probe extension length of 2-3mm, fine-tune the dedicated cold junction compensation offset coefficient until the temperature measurement deviation is stably controlled within ±0.3℃. V. Post-calibration Verification and Record Keeping The entire system was continuously operated for 2 hours, with temperature data monitored throughout. Temperature fluctuations at all measuring points were confirmed to be ≤±0.3℃, with no jumps or drifts. The three calibration parameters and cold junction compensation coefficient were fully recorded in the equipment maintenance log. A new calibration parameter file was exported and backed up locally. The temperature measurement accuracy was recalibrated 3 days later. If no deviation was found, the self-calibration was deemed fully successful.