It is the difference in the millivolt output from the sensing point to the reference point that provides the temperature measurement. Different thermocouple types require different alloy wire combinations.
• Type E (Chromel/Constantan),
• Type J (Iron/Constantan),
• Type K (Chromel/Alumel), and
• Type T (Copper/Constantan)
• Initial Calibration Tolerances as per ASTM E230 & ANSI MC 96.1
• Tolerance – Reference Junction ( 0°C)
• Limits of Error in Thermocouple Wire
Type of Wire | Temperature Range | Standard Grade |
---|---|---|
T | (-200°C to 370°C ) | ±1.8 (1) or ±0.75% |
J | (0°C to 760°C) | ±4 (2.2) or ±0.75% |
E | (-200°C to 870°C) | ±3.1 (1.7) or ±0.50% |
K | (-200°C to 1260°C) | ±4 (2.2) or ±0.75% |
N | (-200°C to1260°C) | ±4 (2.2) or ±0.75% |