# Event recorder time-quality flag Canonical URL: https://eloragrid.ai/symbols/event-recorder-time-quality-flag Publisher: Elora Grid Updated: 2026-11-03 Lookup label: ERTF Drawing use: Schematic Reference families: Manufacturer Representation: Functional block Installation focus: substations Input: Event and clock quality Output: Qualified event timestamp Associates each event record with the declared quality of its timestamp reference. ## In plain English ### What this block does Associates each event record with the declared quality of its timestamp reference. ### A simple example In a substation, a station clock can provide precision timing to process equipment and another timing interface to event recorders. The alarm system should distinguish loss of a distribution path from loss of the external time source. For this reference, the drawing identifies “Event and clock quality” at the input and “Qualified event timestamp” at the output. Timestamp precision and timestamp accuracy differ. ### What the drawings help you do Start at the named input: Event and clock quality. Identify its source device or document and the state represented on the drawing. Follow the named output: Qualified event timestamp. Cross-reference its destination and separate the command from confirmation that the equipment responded. ### Terms - Input: Event and clock quality - Output: Qualified event timestamp - Application reference: An explanation of a named drawing function or circuit relationship; the project documents define the equipment and its connections. Concept diagram: Event and clock quality → ERTF → Qualified event timestamp A reading guide. The entry's original illustration and input/output facts describe this application. - [SEL-2488 satellite-synchronised network clock](https://selinc.com/products/2488/) ## What it represents Associates each event record with the declared quality of its timestamp reference. A station time system provides a shared time reference for protection records, measurements and automation. Different devices can use different timing protocols, so the time source, distribution path and quality information must remain identifiable. In a substation, a station clock can provide precision timing to process equipment and another timing interface to event recorders. The alarm system should distinguish loss of a distribution path from loss of the external time source. For this reference, the drawing identifies “Event and clock quality” at the input and “Qualified event timestamp” at the output. Timestamp precision and timestamp accuracy differ. Show the source and client of each time connection. Required accuracy, holdover, protocol profile and loss-of-time behavior follow the selected application; a common timestamp format does not guarantee synchronized events. 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. ## How to read it - Start at the named input: Event and clock quality. Identify its source device or document and the state represented on the drawing. - Follow the named output: Qualified event timestamp. Cross-reference its destination and separate the command from confirmation that the equipment responded. - Timestamp precision and timestamp accuracy differ. - Show the source and client of each time connection. Required accuracy, holdover, protocol profile and loss-of-time behavior follow the selected application; a common timestamp format does not guarantee synchronized events. ## Information to show or reference - Label the source and connection reference for event and clock quality. - Identify the destination and defined state of qualified event timestamp. - Record the equipment or control-document revision supporting this functional block. - Check this application limit in the project design: Timestamp precision and timestamp accuracy differ. ## Important distinction Timestamp precision and timestamp accuracy differ. 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 - Representation: Functional block - Installation focus: Substations - Input / boundary: Event and clock quality - Output / connection: Qualified event timestamp - Lookup label: ERTF is a library lookup label, not a standard device designation. ## Public references - [SEL-2488 satellite-synchronised network clock](https://selinc.com/products/2488/) — SEL. Public technical context for substation timing and event interfaces. PTP, NTP, IRIG-B, pulse distribution, reference failover and timing quality. The application text and educational graphic are independently authored; the publisher does not certify this representation. ## 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.