TST310

Resistance Temperature Detectors (RTDs) measure temperature based on the property that the resistance of metallic conductors varies with temperature. The core principle is as follows: when temperature changes, the amplitude of lattice vibration in metallic conductors such as platinum and copper alters, which results in varying degrees of obstruction to electron movement and a corresponding change in resistance. Taking Pt100 platinum RTD as an example, its standard resistance is 100 Ω at 0 °C; the resistance increases by approximately 0.385 Ω for every 1 °C rise in temperature, showing highly‑linear characteristics within a certain temperature range. In practical measurements, a constant‑current source or bridge circuit converts resistance variation into electrical signals. 3‑wire / 4‑wire connection is used to eliminate lead‑wire errors. The resistance value is finally converted to temperature according to international standard reference tables.

Standard Application

RTD probes are easy to install. They deliver reliable and accurate temperature measurement in general process applications and provide high operational safety. The probes are especially suitable for measuring gaseous and liquid media in mechanical equipment, laboratory instruments and plants, such as air, water and oil. Without an additional thermowell, the probe housing is in direct contact with the process medium, enabling fast and accurate detection of instantaneous temperature changes.