# Resistance temperature detector

Canonical URL: https://eloragrid.ai/symbols/resistance-temperature-detector
Publisher: Elora Grid
Updated: 2026-10-13
Lookup label: RTD
Drawing use: Schematic
Reference families: IEC, Manufacturer

An RTD is a temperature sensor whose resistance changes with temperature.

## What it represents

An RTD is a temperature sensor whose resistance changes with temperature. Its schematic needs the selected sensor characteristic and two-, three- or four-wire measurement connection.

## How to read it

- Count sensor conductors at the measuring input instead of inferring them from the sensor name.
- The preview is an original explanation of this function. Match the actual drawing convention to its legend and the selected equipment documentation.

## Information to show or reference

- State sensor characteristic
- Show conductor count
- Reference compatible temperature input

## Important distinction

An RTD is different from a discrete temperature switch or a thermocouple voltage source.

## Facts

- Drawing role: Actuated indication
- Representation scope: Functional concept; not an official standard graphic or a product footprint
- Identifier status: The short label is a functional lookup label, not an assigned IEC or IEEE symbol number. Any separately listed Autodesk code is a verified vendor block name.

## Public references

- [RTD and thermocouple temperature transducer inputs](https://www.phoenixcontact.com/en-gb/products/temperature-measuring-transducer-macx-mcr-1ts-i-olp-1145192?type=pdf) — Phoenix Contact. Public documentation of this equipment function or named vendor variant; the illustration is independently authored and is not the source graphic.

## Graphic scope

Independent original educational concept illustration by Elora Grid. Not a certified standards graphic or manufacturer footprint. Unitless; not to scale. Original artwork licence: https://creativecommons.org/licenses/by/4.0/. Publisher material is linked only.