Thermocouples with Built-In Self-testing

The aim of this paper is to create a method of built-in self-testing of thermocouples in situ. This aim is achieved by using the equivalent operating time of the thermocouple. The method does not require replacement of thermocouples from their operating place as it could be done during the operation of the thermocouples. The only necessary condition, that makes self-testing possible, is a constant measuring junction temperature during the procedure of self-testing. The determined equivalent operating time allows finding the place of a given thermocouple in the thermocouple’s drift model as well as in the model of thermoelectric inhomogeneity.