TMS11

The operating principle of Resistance Temperature Detectors (RTDs) is based on the characteristic that the resistance of metallic conductors varies with temperature. The core principle: as temperature changes, the amplitude of lattice vibration in metallic conductors such as platinum and copper changes, creating varying degrees of obstruction to electron movement and resulting in resistance variation. Taking the Pt100 platinum RTD as an example, its nominal resistance is 100 Ω at 0 °C. The resistance increases by approximately 0.385 Ω per 1 °C temperature rise, showing highly linear behaviour within a defined temperature range. For practical measurements, a constant‑current source or bridge circuit converts resistance changes into electrical signals. Three‑wire or four‑wire connection eliminates lead‑wire errors, and resistance values are finally converted to temperature values against international standard reference tables. Thermocouples feature simple structure and rugged construction. Thermocouple sensors perform temperature measurement based on the Seebeck effect. Two dissimilar conductors form a closed loop. A tiny voltage difference is generated in the loop when the two junctions are at different temperatures. This voltage difference is referred to as thermal voltage or thermoelectromotive force. Its magnitude depends on the conductor materials and the temperature difference between the "measuring junction" (junction of the two conductors) and the "cold junction" (open‑circuit ends of the conductors). Accordingly, thermocouples are inherently suited for temperature‑difference measurement. The absolute temperature at the measuring junction can be determined if the cold‑junction temperature is known or measured and compensated separately. Standards IEC 60584 and ASTM E230/ANSI MC96.

High-end Application

The iTHERM TMS11 MultiSens multi‑point rigid thermometer is suitable for oil & gas and chemical industry applications. It can be customized for different operating conditions to meet the highest safety‑standard requirements. Only one process connection is required to monitor temperature at multiple measuring points along the same straight line, which improves process safety. It features simple system integration, reduced installation time and maximum availability.