Functional block · ITI

IRIG-B time-distribution interface

Functional block · Substations

An independently authored application reference. The drawing shows the named function or circuit relationship; use the project legend and selected equipment documentation for its drafting form and connections.

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In plain English

What this block does

Identifies the selected coded time connection between station clock and equipment.

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 “IRIG-B source output” at the input and “Equipment time input” at the output. Signal format and electrical interface must match.

IRIG-B source outputITIEquipment time input
A reading guide. The entry's original illustration and input/output facts describe this application.

What the drawings help you do

Start at the named input: IRIG-B source output. Identify its source device or document and the state represented on the drawing. Follow the named output: Equipment time input. Cross-reference its destination and separate the command from confirmation that the equipment responded.

Input
IRIG-B source output
Output
Equipment time input
Application reference
An explanation of a named drawing function or circuit relationship; the project documents define the equipment and its connections.

Read the source: SEL-2488 satellite-synchronised network clock

Schematic · ITIIRIG-B time-distribution interface: original educational illustration
Original educational illustrationSee source and graphic notes

What it represents

Identifies the selected coded time connection between station clock and equipment. 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 “IRIG-B source output” at the input and “Equipment time input” at the output. Signal format and electrical interface must match.

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: IRIG-B source output. Identify its source device or document and the state represented on the drawing.
  • Follow the named output: Equipment time input. Cross-reference its destination and separate the command from confirmation that the equipment responded.
  • Signal format and electrical interface must match.
  • 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 irig-b source output.
  • Identify the destination and defined state of equipment time input.
  • Record the equipment or control-document revision supporting this functional block.
  • Check this application limit in the project design: Signal format and electrical interface must match.

A distinction that matters

Signal format and electrical interface must match. 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.

Sources you can follow

These public references support the explanation and provide further detail. Their graphics and downloadable files remain with their publishers.

SEL-2488 satellite-synchronised network clock

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.

SEL · Public reference checked 3 November 2026 · Link only

About this graphic

This illustration was authored independently by Elora Grid to explain the concept. It is not reproduced from a customer drawing, an official standard graphic or a manufacturer CAD file. Its correspondence to an exact IEC or IEEE symbol identifier has not been certified.

SVG and DXF downloads contain this original artwork. Original artwork is available under CC BY 4.0. Third-party references retain their own terms.

Entry JSON · Entry Markdown · Last editorial update: 3 November 2026

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