# On-delay normally-open contact

Canonical URL: https://eloragrid.ai/symbols/on-delay-normally-open-contact
Publisher: Elora Grid
Updated: 2026-10-13
Lookup label: TON NO
Drawing use: Schematic
Reference families: IEC, Manufacturer

An on-delay NO contact changes from its unoperated open state only after the associated timing condition has persisted for the documented delay.

## What it represents

An on-delay NO contact changes from its unoperated open state only after the associated timing condition has persisted for the documented delay. The contact tag links it to the timer element.

## How to read it

- The delay applies to the indicated operating transition, not automatically to both directions.
- 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

- Match timer tag
- Label delayed closing
- Reference reset behaviour

## Important distinction

A timed contact adds transition information to the basic normally-open state.

## Facts

- Drawing role: Timed operation
- 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

- [AutoCAD Electrical: Time-delay relays](https://help.autodesk.com/cloudhelp/2021/ENU/AutoCAD-Electrical/files/GUID-DA927086-EEAF-48CB-B9B1-634A4B48C8C7.htm) — Autodesk. 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.