Station telemetry stale-data flag

What it represents

Indicates that a measurement or status has exceeded its defined freshness condition. Station automation collects measurements and statuses and issues assigned commands through defined authority paths. A communicated point has a value, quality and equipment identity; it should not be treated as an unexplained contact.

In a substation control building, the station controller receives bay information and forwards an operator's selected command to the correct bay device. Device feedback confirms whether the intended result actually occurred. For this reference, the drawing identifies “Data age and quality” at the input and “Stale information flag” at the output. Stale data must remain distinguishable from a current value.

Document the point mapping, source, destination, command authority and failure behavior. A communication interface block explains information flow and does not certify network security or control-system availability. 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: Data age and quality. Identify its source device or document and the state represented on the drawing.
• Follow the named output: Stale information flag. Cross-reference its destination and separate the command from confirmation that the equipment responded.
• Stale data must remain distinguishable from a current value.
• Document the point mapping, source, destination, command authority and failure behavior. A communication interface block explains information flow and does not certify network security or control-system availability.

Information to show or reference

• Label the source and connection reference for data age and quality.
• Identify the destination and defined state of stale information flag.
• Record the equipment or control-document revision supporting this functional block.
• Check this application limit in the project design: Stale data must remain distinguishable from a current value.

Sources you can follow

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

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.