# ANSI/IEEE Manually unlatched NO contact form Canonical URL: https://eloragrid.ai/symbols/ansi-manually-unlatched-no-contact Publisher: Elora Grid Updated: 2026-10-28 Lookup label: NO UNLATCH Drawing use: Schematic Reference families: IEEE / ANSI, Manufacturer ## Symbol convention Convention: IEEE / ANSI Form: With Mechanical Block and Manual Unlatching Autodesk IEEE Symbol Preview: Relays and Contacts, block HCR2121F. Matching functional counterpart linked separately. Independently drawn educational geometry; not a certified IEEE glyph or database identifier. Related representation: [Manually unlatched NO contact](https://eloragrid.ai/symbols/manually-unlatched-no-contact) IEEE-library form of manually unlatched no contact: a manually unlatched NO contact includes a mechanical retaining action released by a documented manual operation. ## In plain English ### What does ANSI/IEEE Manually unlatched NO contact form mean? This reference locates manually unlatched no contact in Autodesk's IEEE-oriented relays and contacts family. A manually unlatched normally open contact includes a mechanical retaining action released by a documented manual operation. Its schematic modifier explains why removal of an initiating signal may not restore the initial state. The public library uses HCR2121F for its horizontal representation; this is a vendor block name, not an IEEE standards symbol number. ### A simple example Trace the measured quantity or initiating control signal separately from the output contacts. The device tag links the sensing or operating element to the controlled circuit; settings, reset behaviour and the actual terminal arrangement belong in the selected equipment documentation. ### What the drawings help you do Follow the manual reset to the retaining device tag. Manual unlatching concerns the mechanism, not the contact's load interrupting rating. The linked functional counterpart explains the same operating role in its own drawing context; agreement of every detailed convention mark is not asserted. ### This particular reference IEEE-library form of manually unlatched no contact: a manually unlatched normally open contact includes a mechanical retaining action released by a documented manual operation. Manual unlatching concerns the mechanism, not the contact's load interrupting rating. ### Terms - Normally open / normally closed: The contact state in the normal condition defined for the drawing. - Coil: A wound conductor that can produce a magnetic field when energised. - Terminal: An identified point where a conductor connects. Concept diagram: Identify the device and form → Read the connections and state → Check the equipment reference A guide to reading this reference. The original symbol illustration and its drawing notes appear below; these boxes are not a wiring diagram. - [Autodesk IEEE Symbol Preview — Relays and Contacts](https://help.autodesk.com/cloudhelp/2021/ENU/AutoCAD-Electrical/files/GUID-F8EAC387-53CF-45FE-BE6A-C0C8FB3C1B22.htm) ## What it represents This reference locates manually unlatched no contact in Autodesk's IEEE-oriented relays and contacts family. A manually unlatched NO contact includes a mechanical retaining action released by a documented manual operation. Its schematic modifier explains why removal of an initiating signal may not restore the initial state. The public library uses HCR2121F for its horizontal representation; this is a vendor block name, not an IEEE standards symbol number. Trace the measured quantity or initiating control signal separately from the output contacts. The device tag links the sensing or operating element to the controlled circuit; settings, reset behaviour and the actual terminal arrangement belong in the selected equipment documentation. Follow the manual reset to the retaining device tag. Manual unlatching concerns the mechanism, not the contact's load interrupting rating. The linked functional counterpart explains the same operating role in its own drawing context; agreement of every detailed convention mark is not asserted. ## How to read it - Follow the manual reset to the retaining device tag. - 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 - Identify latch mechanism - Show manual unlatch - Reference contact terminals ## Important distinction Manual unlatching concerns the mechanism, not the contact's load interrupting rating. ## Facts - Convention evidence: Autodesk IEEE Symbol Preview: Relays and Contacts; published form: With Mechanical Block and Manual Unlatching. - Public vendor block: HCR2121F. Vendor library token, not an IEEE symbol number. - Drawing role: Contact state - 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. - Artwork scope: Original educational geometry. Exact standard graphics, product ratings and terminal pinouts are not certified. ## Public references - [Autodesk IEEE Symbol Preview — Relays and Contacts](https://help.autodesk.com/cloudhelp/2021/ENU/AutoCAD-Electrical/files/GUID-F8EAC387-53CF-45FE-BE6A-C0C8FB3C1B22.htm) — Autodesk. Public IEEE-oriented Relays and Contacts table explicitly lists HCR2121F as With Mechanical Block and Manual Unlatching. This supports the vendor convention context, not reproduction of the publisher 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.