Which RTD type is most common in process industries?
A. Pt1000
B. Pt250
C. Pt500
D. Pt100
View Answer
Answer: D
Explanation:
The Pt100 is the most widely used RTD type in process industries due to its excellent balance of accuracy, stability, availability, and compatibility with industrial instruments.
The term Pt100 means:
- Pt = Platinum sensing element
- 100 = 100 Ω resistance at 0°C
Comparison of Common RTD Types
Pt100
- 100 Ω at 0°C
- Most common industrial RTD
- Widely supported by PLCs, DCSs, transmitters, and temperature controllers
- Excellent accuracy and stability
Pt1000
- 1000 Ω at 0°C
- Higher sensitivity than Pt100
- Often used in HVAC and building automation applications
Pt500
- 500 Ω at 0°C
- Less common than Pt100 and Pt1000
Pt250
- Rarely used in industrial applications
Why Pt100 is Preferred
Internationally standardized under IEC 60751
Widely available from all major manufacturers
Suitable for long-distance industrial measurements
Compatible with most temperature transmitters and control systems
Proven reliability in process industries
Because of its widespread adoption and industry acceptance, Pt100 is the most common RTD type used in process industries.
Therefore, Option D (Pt100) is the correct answer.