WHITEPAPER: The Basics of Temperature Measurement Part 2: Using RTDs

The Basics of Temperature Measurement Part 2: Using RTDs

Temperature reigns as the most often measured process parameter in industry. Most industrial applications require that a temperature be measured remotely, and that this signal be transmitted some distance. An industrial transmitter is commonly used to amplify, isolate, and convert the low-level sensor signal to a high level signal suitable for monitoring or retransmission. With respect to these transmitters, your choice of sensor type is generally limited to T/C, or RTD. An RTD or Resistance Temperature Detector is a passive circuit element whose resistance increases with increasing temperature in a predictable manner. This Basics of Temperature Measurement Using RTDs paper is Part 2 of a three-part series that provides information for choosing an industrial temperature sensor from Thermocouple (T/C) and Resistance Temperature Detector (RTD) sensor types. Part 1 of this series took a close look at thermocouples. Part 2 will look similarly at RTDs. Here, we’ll review:

  1. The Basics of Resistance Temperature Detectors
  2. Points of Consideration When Using RTDs to Measure Temperature:
    • Temperature Coefficient of Resistance (TCR)
    • sensitivity
    • accuracy
    • interchangeability and conformity
    • repeatability
    • stability and drift,
    • corrosion and contamination
    • shock and vibration
    • insulation resistance
    • lead-wire resistance
    • self-heating
    • meter-loading
    • packaging and thermal transfer
    • response time
    • thermoelectric effects