{"schemaVersion":1,"slug":"frequency-monitoring-relay","name":"Frequency monitoring relay","kind":"symbol","abbreviation":"f MON","aliases":["HCR1F40","VCR1F40"],"category":"measurement-protection","drawingTypes":["SLD","Schematic"],"referenceFamilies":["Manufacturer"],"summary":"A frequency relay issues a documented output for a configured frequency condition.","description":["A frequency relay issues a documented output for a configured frequency condition. The schematic identifies its measurement input and links its thresholds to the settings record."],"readingNotes":["Determine whether high frequency, low frequency or both are monitored.","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 bus","Reference thresholds and delay","Show output contacts"],"distinction":"A frequency relay applies operating criteria; a frequency meter only indicates the measured value.","facts":[{"label":"Drawing role","value":"Monitoring element"},{"label":"Representation scope","value":"Functional concept; not an official standard graphic or a product footprint"},{"label":"Public vendor block reference","value":"HCR1F40, VCR1F40 (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-monitoring-relays","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","relay-coil"],"artwork":"edu-frequency-monitoring-relay","publishedOn":"2026-10-13","updatedOn":"2026-10-13","provenance":"independent-public-research","url":"https://eloragrid.ai/symbols/frequency-monitoring-relay","illustration":{"url":"https://eloragrid.ai/library/illustrations/frequency-monitoring-relay.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-monitoring-relays","title":"AutoCAD Electrical: Miscellaneous monitoring relays","publisher":"Autodesk","url":"https://help.autodesk.com/cloudhelp/2021/ENU/AutoCAD-Electrical/files/GUID-31F4CF79-F8E0-4E5A-8C51-4D71640ACDB8.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."}]}