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Updated 2025-11-10
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Enumeration

ENUM - Enumeration

User-defined type with named constants representing discrete values.

Key Takeaways

  • User-defined type with named constants representing discrete values.
  • Advanced-level topic in Data Types & Variables
  • Related to: Constant, Subrange, BOOL

Detailed Definition

User-defined type with named constants representing discrete values. This term is essential for understanding data types in industrial automation and PLC programming.

Enumeration is part of the type system defined by IEC 61131-3, the international standard for PLC programming languages. User-defined type with named constants representing discrete values.

The right type choice depends on the value range you actually need, the precision tolerated, the memory budget on your controller, and how the data will be consumed downstream. Choosing too small a type causes overflow bugs that are hard to detect on the bench; choosing too large wastes memory and bandwidth that adds up across thousands of variables on a large project.

For commissioning engineers, the most reliable diagnostic with Enumeration is to inspect the variable in the IDE's online watch table while toggling related inputs — type-mismatch bugs are caught faster by direct observation than by reading code.

Common Questions

What is Enumeration?

User-defined type with named constants representing discrete values.

What prerequisites are needed to understand Enumeration?

As an advanced-level concept, Enumeration requires a solid foundation in PLC fundamentals and intermediate programming concepts. It's recommended to have hands-on experience with Data Types & Variables before diving deep into this topic.

What are related concepts I should learn?

To fully understand Enumeration, you should also familiarize yourself with Constant, Subrange, and BOOL. These concepts work together in industrial automation systems.

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Quick Info

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About Data Types & Variables

Data structures, variable types, and memory organization

Total Terms:30
Difficulty:Beginner to Intermediate

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