Cold-junction compensation (CJC) is a critical technology that ensures accurate temperature measurement in hot runner thermocouples. Thermocouples generate voltage based on the temperature difference between the hot junction at the nozzle and the cold junction at the controller connection. Changes in workshop ambient temperature directly affect the cold-junction reading, leading to measurement errors if not compensated.
Modern hot runner controllers use built-in CJC sensors to monitor the cold-junction temperature and adjust readings automatically. Without effective compensation, ambient temperature fluctuations can cause errors of several degrees Celsius, resulting in unstable melt conditions and molding defects. High-precision systems use high-sensitivity CJC components to maintain accuracy within ±0.5°C.
In factories with large temperature differences between day and night or seasonal changes, CJC becomes even more important. Long cable routes between the mold and controller can amplify ambient influences. Premium thermocouples and controllers work together to provide stable compensation, ensuring consistent performance regardless of environmental changes.
