Post-Installation Basic Verification: First, confirm that the thermocouple installation depth is correct, the sensing end is fully in contact with the hot runner temperature measurement point, the compensating wire's index matches the thermocouple perfectly, and the terminals are securely fastened.
Use a multimeter to measure the thermocouple circuit resistance and insulation resistance, confirming there are no loose connections or short circuits, and the insulation resistance is ≥1MΩ.
Cold Junction Compensation Calibration: Confirm that the cold junction compensation function of the temperature controller is enabled. Place the thermocouple cold junction (terminal) in a 25℃ constant temperature environment. Check that the deviation between the cold junction temperature displayed on the instrument and the actual ambient temperature is ≤±0.5℃, eliminating system errors caused by cold junction temperature drift.
If possible, place the cold junction in an ice bath to maintain 0℃ and directly collect the thermoelectric potential value. Compare it with the standard value of the corresponding calibration table. If the deviation exceeds the allowable range, set a compensation correction value in the instrument.
Currently Installing Basic Verification: First, confirm that the thermocouple is installed at the correct depth, the sensing end is fully in contact with the hot runner temperature measurement point, the hot runner's temperature measurement point, the ... Segmented Temperature Rise
Comparison Calibration
Start the hot runner temperature control system and sequentially set 3-5 commonly used production temperature points. After each temperature point stabilizes, perform a comparative test at the same temperature measurement point in the hot runner using a calibrated standard thermocouple.
At each temperature point, when the furnace temperature change is ≤0.2℃/min, take multiple readings in the forward and reverse order of standard → calibrated → standard. Calculate the temperature error by averaging the thermoelectric potential. If the deviation exceeds ±1℃, fine-tune the temperature offset parameter in the temperature controller to correct the error.
Operating Stability Verification
After the hot runner is heated to the actual production temperature, run it continuously at a constant temperature for 30 minutes to confirm that the temperature display fluctuation range is ≤±1℃, with no jumps or drifts.
Use an infrared thermometer to measure the actual temperature at the corresponding point in the hot runner and compare it with the value displayed on the temperature controller. If the deviation is ≤±3℃, the entire calibration process is complete, and the temperature measurement accuracy fully meets the hot runner production requirements.
This calibration process can completely eliminate system temperature measurement deviations caused by thermocouple replacement, ensuring long-term stability of the hot runner temperature control accuracy.
