Measurement errors can be undetected and highly significant. I had a great example of sensor radiation error recently.

I took a telephone call from a customer telling me my temperature sensors were inaccurate. He was building an AMS 2750D compliant Aerospace Furnace. He bought a number of thermocouples from Peak Sensors which were all UKAS calibrated.

System Design

There was a combination of Mineral Insulated Type N and Ceramic Insulated Type R (wire Ø 0.25mm) sensors. In four locations, a type N and a type R were installed adjacent to each other. One would expect them to read very similar temperatures. During pre commissioning trials it was noticed that at times there was up to 50°C difference between the pair.… Read more