The RTT80 is Schneider Electric's I/A Series temperature transmitter - a dual-channel HART 7 unit that takes RTD or thermocouple inputs and adds SIL 2/3 certification and sensor-health diagnostics.

When do you need two temperature sensors?

On a vessel where a failed sensor stops the line, the RTT80 reads two RTD or TC inputs and averages, differences, or hot-swaps to the backup the moment the primary drifts. The alternative - a single sensor - takes the process down on any failure until someone notices.

Why put SIL 2/3 on a temperature transmitter?

It is TÜV-certified for safety-instrumented loops, so it can sit in a SIL-rated trip without an external certificate. The alternative - a non-SIL transmitter - forces a separate safety relay or excludes temperature from the SIS entirely.

How does it warn before the reading lies?

Drift and corrosion diagnostics catch a sensor going bad before the value corrupts, and 2 kV input-to-output isolation keeps the loop clean. The alternative is a dumb transmitter that fails silently and ships a wrong temperature to the controller.