# Time-client quality rejection interface

Canonical URL: https://eloragrid.ai/symbols/time-client-quality-rejection-interface
Publisher: Elora Grid
Updated: 2026-11-03
Lookup label: TQRI
Drawing use: Schematic
Reference families: Manufacturer

Representation: Functional block
Installation focus: substations
Input: Received time-quality information
Output: Time-reference rejection

Identifies the condition in which a device rejects a timing reference of unacceptable quality.

## In 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.

### Terms

- 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.

Concept diagram: Received time-quality information → TQRI → Time-reference rejection
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

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.

## Important distinction

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.

## Facts

- Representation: Functional block
- Installation focus: Substations
- Input / boundary: Received time-quality information
- Output / connection: Time-reference rejection
- Lookup label: TQRI 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.