Based on your previous focus on hot runner thermocouple temperature measurement scenarios, the common problems in cold junction compensation calibration are as follows:
Inherent Defects of Traditional Methods: The traditional ice-water mixture method is cumbersome to operate, prone to freezing point deviation, and room temperature compensation suffers from fluctuation lag, directly affecting measurement traceability and failing to guarantee calibration accuracy.
Cold Junction Temperature Acquisition Deviation: If the cold junction temperature sensor is not in close contact with the terminals, the acquired temperature will be inconsistent with the actual temperature of the thermocouple cold junction, directly introducing systematic temperature measurement errors and is the most common cause of calibration failure.
Operating Condition Adaptation Errors: Compensation parameters are written under fluctuating temperature conditions without waiting for the cold junction temperature to fully stabilize before calibration, causing the cold junction compensation value to drift with the ambient temperature after calibration, resulting in unstable temperature measurement data.
Parameter Mismatch: Incompatible compensation coefficients for thermocouples of different calibration grades result in a fixed thermoelectric potential deviation after calibration, preventing accurate temperature correction.
Environmental interference: Heat radiation and electromagnetic interference around the hot runner can cause distortion of temperature sampling data during calibration, resulting in calibration results that do not meet the requirements of actual operating conditions.
