RTD temperature measurement

When measuring temperature, the choice of the sensor is one of the most important decisions to make. Thermocouples (TCs) and resistance temperature detectors (RTDs) are commonly used in industrial applications. Proven in the process industry for decades, RTDs work on the principle that the electrical resistance of the sensor metal increases as the temperature rises. This change in resistance is measured and converted into temperature readings.

• High accuracy over a wide temperature range
• Nearly linear response, making them easy to calibrate and interpret
• Suitable for a moderate temperature range: -200°C (300°F) to +850°C (1562°F)
• Good long-term stability and repeatability
• Low self-heating effect, resulting in minimal measurement errors

The Pt100 sensor is also known as a PTC, which stands for "positive temperature coefficient", meaning that the resistance increases as the temperature rises. A Pt100 RTD is suitable for the measurement of temperatures between -200°C (300°F) and +850°C (1562°F), depending on the sensor and the design. It is important to note that RTD sensors do not follow an ideal linear temperature-resistance curve and, unfortunately, the RTD becomes less linear as the temperature rises. The use of temperature transmitters can compensate these non-linearities. Endress+Hauser developed innovative, patented sensor technologies such as the iTHERM StrongSens with highest vibration resistance, the fast-responding sensor iTHERM QuickSens and the iTHERM TrustSens with self-calibration function. Endress+Hauser RTD instruments meet the IEC 60751 accuracy class A as standard.