TMT82

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 effect of cold‑junction temperature variation), weak thermoelectromotive force is amplified, and linearization is carried out (since thermoelectromotive force has a non‑linear relationship with temperature). For RTD signals: normally powered by a constant‑current source, resistance variation is converted into voltage variation, which also undergoes linearization (due to the non‑linear resistance‑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. With strong anti‑interference capability, it is suitable for long‑distance transmission to control systems.

Mid‑range Application

The iTEMP TMT82 temperature transmitter offers high reliability, high measurement accuracy and excellent long‑term stability to meet high‑availability requirements for industrial processes. This dual‑channel transmitter features wide application scope. It reliably scales input signals from universal sensors such as thermocouples or RTDs into 4 to 20 mA output signals and HART® signals. Equipped with intelligent sensor self‑monitoring, it outputs diagnostic status information compliant with NAMUR NE 107. SIL 2 and SIL3 certified versions effectively improve process safety and extend uptime.