RTD PT100 Temperature Sensor Standards

There are two standards for Pt100 RTDs: the European standard, also known as the DIN or IEC standard, and the American standard The European standard is considered the world-wide standard for platinum RTDs. This standard, DIN/IEC 60751 (or simply IEC751), requires the RTD to have an electrical resistance of 100.00 O at 0°C and a temperature coefficient of resistance (TCR) of 0.00385 O/O/°C between 0 and 100°C. 

There are two resistance tolerances specified in DIN/IEC751: 
Class A = ±(0.15 + 0.002*t)°C or 100.00 ±0.06 O at 0ºC 
Class B = ±(0.3 + 0.005*t)°C or 100.00 ±0.12 O at 0ºC 

Two resistance tolerances used in industry are: 
1/3 DIN = ±1/3* (0.3 + 0.005*t)°C or 100.00 ±0.10 O at 0ºC 
1/10 DIN = ±1 /10* (0.3 + 0.005*t)°C or 100.00 ±0.03 O at 0ºC