{"schemaVersion":1,"slug":"frequency-meter","name":"Frequency meter","kind":"symbol","abbreviation":"Hz","aliases":["HIN1FRM","VIN1FRM"],"category":"measurement-protection","drawingTypes":["SLD","Schematic"],"referenceFamilies":["IEC","Manufacturer"],"summary":"A frequency meter indicates the frequency of its measured input.","description":["A frequency meter indicates the frequency of its measured input. The source of that input must be clear when multiple buses or generators are present."],"readingNotes":["Trace the measurement to the correct bus or VT circuit.","The preview is an original explanation of this function. Match the actual drawing convention to its legend and the selected equipment documentation."],"drawingChecklist":["Name measured source","State input range","Reference auxiliary supply"],"distinction":"A frequency meter displays a quantity; an underfrequency relay applies an operating threshold.","facts":[{"label":"Drawing role","value":"Indicated quantity"},{"label":"Representation scope","value":"Functional concept; not an official standard graphic or a product footprint"},{"label":"Public vendor block reference","value":"HIN1FRM, VIN1FRM (Autodesk identifiers; not IEC symbol numbers)"},{"label":"Identifier status","value":"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."}],"references":[{"sourceId":"pub-symbol-instrumentation","relevance":"Public documentation of this equipment function or named vendor variant; the illustration is independently authored and is not the source graphic."}],"related":["current-transformer","voltage-transformer"],"artwork":"edu-frequency-meter","publishedOn":"2026-10-13","updatedOn":"2026-10-13","provenance":"independent-public-research","url":"https://eloragrid.ai/symbols/frequency-meter","illustration":{"url":"https://eloragrid.ai/library/illustrations/frequency-meter.svg","scope":"Original educational concept; not an official standard graphic or product footprint","license":"https://creativecommons.org/licenses/by/4.0/"},"sources":[{"id":"pub-symbol-instrumentation","title":"AutoCAD Electrical: Instrumentation and sensors","publisher":"Autodesk","url":"https://help.autodesk.com/cloudhelp/2021/ENU/AutoCAD-Electrical/files/GUID-773A36C3-44C6-43EB-9BD0-E0297816B9B2.htm","type":"cad-reference","scope":"Public vendor catalogue naming and functional variants. Vendor block names are not IEC identifiers. Linked for reference; no graphics or CAD files are redistributed.","checkedOn":"2026-10-13","reuse":"link-only","relevance":"Public documentation of this equipment function or named vendor variant; the illustration is independently authored and is not the source graphic."}]}