TON NO
On-delay normally-open contact
An on-delay NO contact changes from its unoperated open state only after the associated timing condition has persisted for the documented delay.
Schematic
IEEE / ANSI · TON NO
ANSI/IEEE on-delay normally-open contact symbol
IEEE-oriented graphical reference for on-delay normally-open contact, with public vendor evidence and drawing-reading notes.
IEEE / ANSI · Autodesk IEEE-oriented Time Delay Relays functional form
Autodesk explicitly publishes this block under IEEE Symbol Preview. The counterpart is the matching functional concept; no equivalence of every detailed standard graphic is asserted.
Shown as an independently authored educational illustration. Use the cited publication and drawing legend to verify the required drafting form.
Schematic · TON NO
What it represents
The on-delay NO contact form specifically describes a delayed-closing transition. Its timer reference supplies the initiating condition and interval, while the unoperated contact remains open; release or reset behaviour comes from the documented timing chart.
This is a convention-specific lookup based on the publisher's IEEE-labelled preview. The geometry here is independently drawn to explain the connection or operation; it is not a certified reproduction of the standard graphic.
How to read it
- Separate the delay-close transition from the contact's return action.
- Read the selected library and the project legend together. A vendor block identifier is meaningful within its named library and is not a universal standard-symbol code.
Information to show or reference
- Link timer element
- State closing delay
- Reference reset behaviour
A distinction that matters
A timed output contact differs from the timer coil or trigger that initiates its timing.
Sources you can follow
These public references support the explanation and provide further detail. Their graphics and downloadable files remain with their publishers.
Autodesk IEEE Symbol Preview — Time Delay Relays
Exact public IEEE-oriented category page verifying the component name and vendor block identifier.
IEEE/ANSI 315-1975: graphic symbols for electrical and electronics diagrams
Graphic-symbol standards context and official status; not a source of reproduced artwork.
About this graphic
This illustration was authored independently by Elora Grid to explain the concept. It is not reproduced from a customer drawing, an official standard graphic or a manufacturer CAD file. Its correspondence to an exact IEC or IEEE symbol identifier has not been certified.
SVG and DXF downloads contain this original artwork. DXF uses unscaled drawing units; a GA envelope supplies no product dimensions, clearances or fabrication information. Original artwork is available under CC BY 4.0. Third-party references retain their own terms.
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