Which RTD accuracy class provides the highest accuracy?
A. Class A
B. Class B
C. Class C
D. Class D
View Answer
Answer: A
Explanation:
According to the IEC 60751 standard, RTDs are classified into different accuracy classes based on their allowable measurement error.
Among the given options, Class A provides the highest accuracy.
RTD Accuracy Classes
| Class | Typical Accuracy at 0°C |
|---|---|
| Class A | ±0.15°C |
| Class B | ±0.30°C |
| Class C | ±0.60°C |
| Class D | ±1.20°C |
The tolerance for a Class A RTD is:
Where:
- T = Temperature in °C
This means Class A RTDs have tighter tolerances and lower measurement uncertainty than Class B, C, or D RTDs.
Why Use Class A RTDs?
Higher measurement accuracy
Better process control
Improved calibration performance
Suitable for critical industrial applications
Reduced temperature measurement uncertainty
Class A RTDs are commonly used in process industries, laboratories, pharmaceutical plants, and applications where precise temperature measurement is important.
Therefore, Option A (Class A) is the correct answer.