What is 1/3 DIN and 1/10 DIN?

Standard DIN EN 60751:2009 (based on IEC 60751:2008) defines Pt100 resistance accuracy Classes AA, A, B and C and corresponding tolerances. Before standard update the most accurate class was A and all definitions more accurate were non-standardized, divided Class B values.

• 1/3 DIN is a divided value, based on Class B, not applicable over the whole measuring range. This divided accuracy is only defined at the point: 0 °C = ± 0,3/3 °C= ± 0,1 °C. Class B 1/3 DIN is not a standardized class.
• 1/10 DIN is a divided value, based on Class B, not applicable over the whole measuring range. This divided accuracy is only defined at the point: 0 °C = ± 0,3/10 °C = ± 0,03 °C. Class B 1/10 DIN is not a standardized class.

The standardized Class AA since standard update has made the divided values 1/3 DIN dispensable.