SOE
Sequence-of-events recorder
Recorder that timestamps changes of state on many binary inputs so the order of operations can be reconstructed.
Schematic
Functional block · SUDB
Station UTC-local display boundary
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.
Browse this installation focusIn plain English
What this block does
Separates the common recorded time basis from an operator's displayed local time.
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 “Recorded UTC time” at the input and “Local display time” at the output. Daylight-saving display changes must not alter event identity.
What the drawings help you do
Start at the named input: Recorded UTC time. Identify its source device or document and the state represented on the drawing. Follow the named output: Local display time. Cross-reference its destination and separate the command from confirmation that the equipment responded.
- Input
- Recorded UTC time
- Output
- Local display time
- 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 · SUDB
What it represents
Separates the common recorded time basis from an operator's displayed local time. 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 “Recorded UTC time” at the input and “Local display time” at the output. Daylight-saving display changes must not alter event identity.
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: Recorded UTC time. Identify its source device or document and the state represented on the drawing.
- Follow the named output: Local display time. Cross-reference its destination and separate the command from confirmation that the equipment responded.
- Daylight-saving display changes must not alter event identity.
- 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 recorded utc time.
- Identify the destination and defined state of local display time.
- Record the equipment or control-document revision supporting this functional block.
- Check this application limit in the project design: Daylight-saving display changes must not alter event identity.
A distinction that matters
Daylight-saving display changes must not alter event identity. 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.
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.
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Put the reference into a drawing workflow.
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