{"schemaVersion":1,"slug":"merging-unit-time-quality-interface","name":"Merging-unit time-quality interface","kind":"symbol","abbreviation":"MTI","aliases":["Digital substation process interfaces","substations Digital substation process interfaces","substations","Substations","Time synchronization health","Measurement timing-quality indication"],"category":"measurement-protection","drawingTypes":["Schematic"],"referenceFamilies":["Manufacturer"],"summary":"Identifies the timing-quality status associated with the published measurement information.","description":["Identifies the timing-quality status associated with the published measurement information. Digital substation interfaces carry measurements, status and control information between primary equipment and protective devices. Measurement streams, event messages and time synchronization are separate dependencies even when they share an Ethernet network.","In a digital substation bay, a merging unit digitizes local measurements and a protective relay subscribes to the assigned data stream. The command return path and communication-health indications are drawn separately. For this reference, the drawing identifies “Time synchronization health” at the input and “Measurement timing-quality indication” at the output. Time quality and data quality need separate interpretation.","Identify publisher, subscriber, data meaning and quality handling. Protocol labels alone do not establish protection performance, compatibility or network redundancy; these need the selected system configuration and validation. The functional block is an independent explanation of this named application. Equipment-specific ratings, terminal connections and operating conditions must be established in the project documentation."],"readingNotes":["Start at the named input: Time synchronization health. Identify its source device or document and the state represented on the drawing.","Follow the named output: Measurement timing-quality indication. Cross-reference its destination and separate the command from confirmation that the equipment responded.","Time quality and data quality need separate interpretation.","Identify publisher, subscriber, data meaning and quality handling. Protocol labels alone do not establish protection performance, compatibility or network redundancy; these need the selected system configuration and validation."],"drawingChecklist":["Label the source and connection reference for time synchronization health.","Identify the destination and defined state of measurement timing-quality indication.","Record the equipment or control-document revision supporting this functional block.","Check this application limit in the project design: Time quality and data quality need separate interpretation."],"distinction":"Time quality and data quality need separate interpretation. This reference describes the named application; it does not establish a new IEC graphical symbol, an ANSI device-function number or an exact manufacturer connection diagram.","facts":[{"label":"Representation","value":"Functional block"},{"label":"Installation focus","value":"Substations"},{"label":"Input / boundary","value":"Time synchronization health"},{"label":"Output / connection","value":"Measurement timing-quality indication"},{"label":"Lookup label","value":"MTI is a library lookup label, not a standard device designation."}],"references":[{"sourceId":"pi26-sampled-values","relevance":"Public technical context for digital substation process interfaces. Merging units, sampled measurements, GOOSE, process bus and network redundancy. The application text and educational graphic are independently authored; the publisher does not certify this representation."}],"related":["numerical-protection-relay","optical-fibre-cable","digital-breaker-command-output-boundary"],"artwork":"pi26-merging-unit-time-quality-interface","publishedOn":"2026-11-03","updatedOn":"2026-11-03","provenance":"independent-public-research","representation":{"type":"functional-block","focus":"substations","family":"digital-substation","input":"Time synchronization health","output":"Measurement timing-quality indication"},"plainEnglish":{"title":"What this block does","introduction":"Identifies the timing-quality status associated with the published measurement information.","example":"In a digital substation bay, a merging unit digitizes local measurements and a protective relay subscribes to the assigned data stream. The command return path and communication-health indications are drawn separately. For this reference, the drawing identifies “Time synchronization health” at the input and “Measurement timing-quality indication” at the output. Time quality and data quality need separate interpretation.","drawings":"Start at the named input: Time synchronization health. Identify its source device or document and the state represented on the drawing. Follow the named output: Measurement timing-quality indication. Cross-reference its destination and separate the command from confirmation that the equipment responded.","terms":[{"name":"Input","meaning":"Time synchronization health"},{"name":"Output","meaning":"Measurement timing-quality indication"},{"name":"Application reference","meaning":"An explanation of a named drawing function or circuit relationship; the project documents define the equipment and its connections."}],"diagram":"flow","steps":["Time synchronization health","MTI","Measurement timing-quality indication"],"caption":"A reading guide. The entry's original illustration and input/output facts describe this application.","sources":[{"label":"Digital secondary systems: Sampled Values","url":"https://selinc.com/solutions/digital-secondary-systems/sampled-values/"}],"profileId":"power-installation-digital-substation"},"url":"https://eloragrid.ai/symbols/merging-unit-time-quality-interface","illustration":{"url":"https://eloragrid.ai/tools/electrical-library/illustrations/merging-unit-time-quality-interface.svg","scope":"Original educational concept; not an official standard graphic or product footprint","license":"https://creativecommons.org/licenses/by/4.0/"},"sources":[{"id":"pi26-sampled-values","publisher":"SEL","title":"Digital secondary systems: Sampled Values","url":"https://selinc.com/solutions/digital-secondary-systems/sampled-values/","scope":"Merging units, sampled measurements, GOOSE, process bus and network redundancy.","type":"manufacturer","checkedOn":"2026-11-03","reuse":"link-only","relevance":"Public technical context for digital substation process interfaces. Merging units, sampled measurements, GOOSE, process bus and network redundancy. The application text and educational graphic are independently authored; the publisher does not certify this representation."}]}