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 · TQRI
Time-client quality rejection 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.
Browse this installation focusIn plain English
What this block does
Identifies the condition in which a device rejects a timing reference of unacceptable quality.
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 “Received time-quality information” at the input and “Time-reference rejection” at the output. Rejection criteria are device-specific.
What the drawings help you do
Start at the named input: Received time-quality information. Identify its source device or document and the state represented on the drawing. Follow the named output: Time-reference rejection. Cross-reference its destination and separate the command from confirmation that the equipment responded.
- Input
- Received time-quality information
- Output
- Time-reference rejection
- 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 · TQRI
What it represents
Identifies the condition in which a device rejects a timing reference of unacceptable quality. 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 “Received time-quality information” at the input and “Time-reference rejection” at the output. Rejection criteria are device-specific.
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: Received time-quality information. Identify its source device or document and the state represented on the drawing.
- Follow the named output: Time-reference rejection. Cross-reference its destination and separate the command from confirmation that the equipment responded.
- Rejection criteria are device-specific.
- 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 received time-quality information.
- Identify the destination and defined state of time-reference rejection.
- Record the equipment or control-document revision supporting this functional block.
- Check this application limit in the project design: Rejection criteria are device-specific.
A distinction that matters
Rejection criteria are device-specific. 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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