In mid-June 2026, NPL and CCPI Europe met at CCPI’s manufacturing facility in Sheffield, UK to discuss and demonstrate software being developed for automating operation of the NPL/CCPI self-validating thermocouples (trade name INSEVA). The software is being developed as part of ThermoSI. It automatically finds and characterises the melting plateaus observed during the change of phase (melting) of a miniature cell containing a pure metal or metal-carbon alloy embedded in the thermocouple tip; this invariant temperature provides an in-situ calibration which means the sensor drift can be monitored in real-time.

Schematic: The self-validating thermocouple, illustrating the miniature fixed-point cell (temperature reference) close to the measurement junction.

The software is now mature and is ready for testing at stakeholders’ sites. Several INSEVA units are already being trialled by several organisations. It is mainly of interest to those who are concerned with high temperature heat treatment and other types of metal processing, which requires very high stability (low drift) of the thermocouples used for process measurement and control. The software will maximise the uptake of INSEVA by making it wholly autonomous.

Figure: Screengrab of the automation software, illustrating a plot of the thermocouple drift, as determined in-situ using the self-validating thermocouple.