RTD stands for Resistance Temperature Detector. RTD can be of different material which work on the principal that with change in temperature resistance of metal changes.
The most commonly used metal for RTD is Platinum a it is most stable element and with high repeatability and stability i.e higher accuracy for longer range of temperature.
DIN or IEC Standard recommended id IEC 751
Types of RTD
The various type of sensing element available for Platinum (Pt) Pt 100, Pt 500, Pt 100.
By Pt 100 it means that sensing element Platinum will have resistance of 100 ohms at 0 deg C
Generally RTD is used for 350-400 deg C of Temperature beyond which Thermocouples are recommended.
The RTD configurations available are
- Two wire configuration
- Three wire configuration ( most used one) as it compensate lead wire ressistance.
- Four wire configuration
RTD Accuracy
It is generally available in two accuracy classes
a) Class A :- t +/- (0.15+/-0.002) Range -250 to 650 deg C
b) Class B :- t+/-(0.30+/-0.005) Less stringent Range -250 to 800 deg C