For the highest degree of accuracy and reliability, choose the 4-wire RTD. Unlike a 3-wire RTD, a 4-wire RTD circuit cancels out all errors due to length and resistance imbalance between the leads. Conse- quently, a 4-wire RTD does not have to be replaced if work hardening or corrosion occurs.
The resistance temperature detector (RTD), is a thin film device made of platinum, which is used for measuring temperature.