Specification :

As sensor for temperature measuring and regulation, industrial-purpose thermocouple is usually connected with display meter and other meters to directly measure temperature of liquid, vapor, gas and solid surface ranging from -40 to 1800 .
Thermocouple is based on physical phenomenon that two conductor of different materials is connected to form return circuit, when temperature on both contact is different, it results in thermoelectric potential in return circuit.
Assembly thermocouple is usually composed with temperature sensing element, Mounting & Fixing device and Junction Box.

Measuring Range & Tolerance
Filament Type Graduation Accuracy Class
I II III
Tolerance ± Measuring Range  Tolerance ± Measuring Range  Tolerance ± Measuring Range 
Ni Cr-Ni Si K 1.5 or 0.4% t -40~ 1000 2.5 or 0.75% t -40~ 1000 2.5 or 0.75% t -200~ 40
Ni Cr Si-Ni Si N -40~ 1100 -40~ 1100 -200~ 40
Ni Ci-Constantan E -40~ 800 -40~ 800 -200~ 40
Fe-Constantan J -40~ 750 -40~ 750 ---
Cu-Constantan T 0.5 or 0.4% t -40~ 350 1 or 0.75% t -40~ 350 1 or 0.75% t -200~ 40
Pt Rh10-Pt S 1 or 1+  t-1100 y0.003 0~ 1600 1.5 or 0.25% t 0~ 1600 --- ---
Pt RH13-Pt R 0~ 1600 0~ 1600
6 Pt Rh30-Pt Rh6 B --- --- 600~ 1700 4 or 1.5% t 600~ 1700

Thermocouple Time Constant
index of thermal inertia Time constant ( second) index of thermal inertia Time constant ( second)
` 90-180 III 10-30
a 30-90 IV  10