# Microgrid measurement stale-data supervisor

Canonical URL: https://eloragrid.ai/symbols/microgrid-measurement-stale-data-supervisor
Publisher: Elora Grid
Updated: 2026-11-03
Lookup label: MMSS
Drawing use: Schematic
Reference families: Manufacturer

Representation: Functional block
Installation focus: microgrids
Input: Measurement age and quality
Output: Stale-data indication

Marks the assigned power-system measurement invalid when its defined freshness condition is exceeded.

## In plain English

### What this block does

Marks the assigned power-system measurement invalid when its defined freshness condition is exceeded.

### A simple example

In a microgrid control room, the operator can see source availability, active constraints and current operating mode. A communication failure should remain distinguishable from an electrical resource failure. For this reference, the drawing identifies “Measurement age and quality” at the input and “Stale-data indication” at the output. The permitted age depends on the control use.

### What the drawings help you do

Start at the named input: Measurement age and quality. Identify its source device or document and the state represented on the drawing. Follow the named output: Stale-data indication. Cross-reference its destination and separate the command from confirmation that the equipment responded.

### Terms

- Input: Measurement age and quality
- Output: Stale-data indication
- Application reference: An explanation of a named drawing function or circuit relationship; the project documents define the equipment and its connections.

Concept diagram: Measurement age and quality → MMSS → Stale-data indication
A reading guide. The entry's original illustration and input/output facts describe this application.

- [Microgrid control systems](https://selinc.com/services/microgrids-power-management/microgrid-control-systems/)


## What it represents

Marks the assigned power-system measurement invalid when its defined freshness condition is exceeded. Microgrid supervision coordinates measurements, control authority and resource communication without replacing local protection. Each resource value needs a named measurement boundary, freshness condition and intended control use.
In a microgrid control room, the operator can see source availability, active constraints and current operating mode. A communication failure should remain distinguishable from an electrical resource failure. For this reference, the drawing identifies “Measurement age and quality” at the input and “Stale-data indication” at the output. The permitted age depends on the control use.
Identify signal ownership, quality flags, control priority and loss-of-data behavior. These functional references do not certify cyber security, closed-loop performance or equipment interoperability. 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: Measurement age and quality. Identify its source device or document and the state represented on the drawing.
- Follow the named output: Stale-data indication. Cross-reference its destination and separate the command from confirmation that the equipment responded.
- The permitted age depends on the control use.
- Identify signal ownership, quality flags, control priority and loss-of-data behavior. These functional references do not certify cyber security, closed-loop performance or equipment interoperability.

## Information to show or reference

- Label the source and connection reference for measurement age and quality.
- Identify the destination and defined state of stale-data indication.
- Record the equipment or control-document revision supporting this functional block.
- Check this application limit in the project design: The permitted age depends on the control use.

## Important distinction

The permitted age depends on the control use. 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: Microgrids
- Input / boundary: Measurement age and quality
- Output / connection: Stale-data indication
- Lookup label: MMSS is a library lookup label, not a standard device designation.

## Public references

- [Microgrid control systems](https://selinc.com/services/microgrids-power-management/microgrid-control-systems/) — SEL. Public technical context for microgrid supervisory and communication interfaces. Active and reactive power, generation, load control, operating reserves and system supervision. 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.