TMT162

The core principle of a temperature transmitter is to convert the non‑electrical quantity (temperature) sensed by temperature sensors into standard electrical signals. It connects to sensors such as thermocouples (TC) or Resistance Temperature Detectors (RTD). For thermocouple signals: cold‑junction compensation is performed (to correct the influence of cold‑junction temperature variation), the weak thermoelectromotive force is amplified, and linearization is carried out (because thermoelectromotive force has a non‑linear relationship with temperature). For RTD signals: powered generally by a constant‑current source, the resistance variation is converted into voltage variation, which also undergoes linearization (due to the non‑linear resistance‑to‑temperature relationship). The circuit also filters signals to suppress interference. The conditioned voltage signal is fed into a voltage‑to‑current conversion circuit (V/I converter), which accurately converts it into the industry‑standard 4‑20 mA DC current signal (or other standard signals). The magnitude of this current signal corresponds linearly to the measured temperature range. Featuring strong anti‑interference capability, it is suitable for long‑distance transmission to control systems.

High‑end Application

It delivers outstanding reliability, accuracy and long‑term stability for critical process applications across all industries. Connected to remote temperature transmitters, it transmits converted signals from RTD sensors and thermocouples. It also transmits resistance and voltage signals via HART®, FOUNDATION Fieldbus™ H1 or PROFIBUS® PA communication. Signals can be displayed on a back‑lit screen. The rugged housing is suitable for field mounting, enabling direct deployment in demanding process areas, and is also an option for hygienic applications.