Preparation Before Calibration Prepare a Class II standard thermocouple, a low-potential DC potentiometer with an accuracy of 0.02, and a handheld thermocouple calibrator. Confirm that all standard equipment is within its calibration validity period.
Confirm that the Husky temperature controller and hot runner heating system are functioning normally, and that the thermocouple wiring is secure and not loose. Preheat the system for 15-30 minutes to allow it to stabilize.
Appearance and Condition Verification Inspect the Husky thermocouple to be calibrated for any external damage, ensuring the thermocouple electrodes are free from oxidation and corrosion, and that the insulation is intact and undamaged. Confirm that the thermocouple calibration number matches the temperature controller setting perfectly.
Place both the measuring ends of the standard thermocouple and the thermocouple to be calibrated at the same measuring point in the hot runner constant temperature zone, ensuring they are in identical temperature fields. Strictly distinguish between positive and negative terminals during wiring to avoid reverse connection.
Multi-Temperature Point Comparison Calibration
Increase the temperature point gradually from the lowest to the highest. After reaching each preset calibration temperature, maintain a constant temperature for at least 30 minutes to ensure a stable temperature field, with furnace temperature variation ≤0.2℃/min.
Use a standard-calibrated-standard forward and reverse cyclic reading sequence. Each temperature point should be measured at least four times. Record the thermoelectric potential value of the standard thermocouple and the output value of the calibrated thermocouple, and calculate the error by averaging the two values.
For low-temperature calibration points below 300℃, comparison with a second-class standard mercury thermometer can be performed in an oil constant-temperature bath. The oil bath temperature variation should be controlled within ≤±0.1℃.
Error Correction and Parameter Setting
Calculate the indication error at each calibration point, convert the error value into a temperature offset correction value, and enter the corresponding temperature offset compensation parameters in the Husky temperature controller's calibration parameter setting interface.
After completing the parameter settings, start the temperature controller's PID self-tuning program to adapt the system to the new thermocouple characteristics and optimize the temperature control curve.
Post-calibration verification closed loop: Run continuously at a constant temperature for 30 minutes to confirm that the deviation between the temperature displayed by the temperature controller and the measured temperature of the standard thermocouple is ≤ ±1℃, and the temperature fluctuation range is ≤ ±1℃.
Complete the calibration record, including equipment information, standard information, raw data for each temperature point, error correction values, and calibration conclusions. Sign and archive the record to create a traceable calibration file.
This calibration procedure is fully adapted to the thermocouple calibration requirements in Husky hot runner scenarios, and the calibration results comply with national metrological standards.
