PLC I/O
PLC input / output
A controller interface point connecting field signals to an identified module channel.
Schematic
Protection functions · 34
Master sequence device
Coordinates the steps of a machine or switching sequence.
SLD / Schematic · 34
What it represents
Coordinates the steps of a machine or switching sequence.
In a drafting package, connect this reference to the sequence step inputs and transition conditions. The associated drawing should trace the step outputs and unit sequence diagram; the number identifies the role and does not specify the terminal arrangement, ratings or operating settings.
How to read it
- Identify the sequence step inputs and transition conditions.
- Trace the step outputs and unit sequence diagram.
Information to show or reference
- Label the sequence step inputs and transition conditions.
- Cross-reference the step outputs and unit sequence diagram.
- Identify the device tag, manual revision and logic drawing that define this implementation.
A distinction that matters
A master sequence device sequences operations; device 10 determines the order of multiple units.
Sources you can follow
These public references support the explanation and provide further detail. Their graphics and downloadable files remain with their publishers.
ANSI device-number and suffix reference table
Public manufacturer number/name association. Drafting explanations are independently written.
IEEE C37.2-2022: power-system device function numbers
Normative device-number publication; exact edition wording and compliance require the licensed standard.
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. DXF uses unscaled drawing units; a GA envelope supplies no product dimensions, clearances or fabrication information. Original artwork is available under CC BY 4.0. Third-party references retain their own terms.
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