Functional block · CMP

Current-measurement merging-unit publisher

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.

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In plain English

What this block does

Publishes the assigned sampled current quantities from the selected local measurement interface.

A simple example

In a digital substation bay, a merging unit digitizes local measurements and a protective relay subscribes to the assigned data stream. The command return path and communication-health indications are drawn separately. For this reference, the drawing identifies “Local current measurements” at the input and “Published sampled current stream” at the output. The stream configuration must identify its measurements.

Local current measurementsCMPPublished sampled current stream
A reading guide. The entry's original illustration and input/output facts describe this application.

What the drawings help you do

Start at the named input: Local current measurements. Identify its source device or document and the state represented on the drawing. Follow the named output: Published sampled current stream. Cross-reference its destination and separate the command from confirmation that the equipment responded.

Input
Local current measurements
Output
Published sampled current stream
Application reference
An explanation of a named drawing function or circuit relationship; the project documents define the equipment and its connections.

Read the source: Digital secondary systems: Sampled Values

Schematic · CMPCurrent-measurement merging-unit publisher: original educational illustration
Original educational illustrationSee source and graphic notes

What it represents

Publishes the assigned sampled current quantities from the selected local measurement interface. Digital substation interfaces carry measurements, status and control information between primary equipment and protective devices. Measurement streams, event messages and time synchronization are separate dependencies even when they share an Ethernet network.

In a digital substation bay, a merging unit digitizes local measurements and a protective relay subscribes to the assigned data stream. The command return path and communication-health indications are drawn separately. For this reference, the drawing identifies “Local current measurements” at the input and “Published sampled current stream” at the output. The stream configuration must identify its measurements.

Identify publisher, subscriber, data meaning and quality handling. Protocol labels alone do not establish protection performance, compatibility or network redundancy; these need the selected system configuration and validation. 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: Local current measurements. Identify its source device or document and the state represented on the drawing.
  • Follow the named output: Published sampled current stream. Cross-reference its destination and separate the command from confirmation that the equipment responded.
  • The stream configuration must identify its measurements.
  • Identify publisher, subscriber, data meaning and quality handling. Protocol labels alone do not establish protection performance, compatibility or network redundancy; these need the selected system configuration and validation.

Information to show or reference

  • Label the source and connection reference for local current measurements.
  • Identify the destination and defined state of published sampled current stream.
  • Record the equipment or control-document revision supporting this functional block.
  • Check this application limit in the project design: The stream configuration must identify its measurements.

A distinction that matters

The stream configuration must identify its measurements. 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.

Digital secondary systems: Sampled Values

Public technical context for digital substation process interfaces. Merging units, sampled measurements, GOOSE, process bus and network redundancy. The application text and educational graphic are independently authored; the publisher does not certify this representation.

SEL · Public reference checked 3 November 2026 · Link only

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.

Entry JSON · Entry Markdown · Last editorial update: 3 November 2026

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