Thermocouple drift is the potential for thermocouples to lose accuracy over time. Thermocouple drift is more common when a thermocouple has been operating at higher temperatures for a prolonged period. Thermocouples operating within normal operating parameters or at ambient temperatures may still drift but will do so much slower. Thermocouples can be periodically calibrated against standards to ensure thermocouple drift is known. Thermocouples that have drifted can either be replaced with new sensors or instrumentation can be adjusted to allow for the discrepancy depending on what is best for the application.
We can conduct thermocouple calibration for any sensors that you require, or supply new replacement thermocouples. Give us a call or send us an email.
Cambridge University Materials Science Department has an in-depth explanation of thermocouple drift here.