Learn PLCs free
Data Types & VariablesIntermediateAdvanced
1 min read
Updated 2025-11-10
Intermediate

LWORD

LWORD

LWORD means Long Word — a 64-bit unsigned data type, range 0 to 18,446,744,073,709,551,615. Used for nanosecond-resolution timestamps and very large bit-packed registers.

Key Takeaways

  • LWORD means Long Word — a 64-bit unsigned data type, range 0 to 18,446,744,073,709,551,615. Used for nanosecond-resoluti...
  • Intermediate-level topic in Data Types & Variables
  • Related to: DWORD, LINT, ULINT

Detailed Definition

64-bit long word for extended bit string operations. This term is essential for understanding data types in industrial automation and PLC programming.

LWORD is part of the type system defined by IEC 61131-3, the international standard for PLC programming languages. 64-bit long word for extended bit string operations.

Picking the wrong type is one of the most common sources of subtle PLC bugs — overflow on the small side, wasted memory and slower scan cycles on the large side. Experienced PLC engineers reach for the smallest type that comfortably covers their value range plus a safety margin.

For commissioning engineers, the most reliable diagnostic with LWORD 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 LWORD?

LWORD means Long Word — a 64-bit unsigned data type, range 0 to 18,446,744,073,709,551,615. Used for nanosecond-resolution timestamps and very large bit-packed registers.

What are related concepts I should learn?

To fully understand LWORD, you should also familiarize yourself with DWORD, LINT, and ULINT. These concepts work together in industrial automation systems.

Was this helpful?

Let us know if this glossary term helped you understand LWORD better.

Your feedback helps us improve our glossary and create better content for the PLC programming community.

Quick Info

Difficulty
Intermediate
Tier
Advanced

About Data Types & Variables

Data structures, variable types, and memory organization

Total Terms:30
Difficulty:Beginner to Intermediate

Free PLC simulator

Stop reading, start doing

Write ladder logic in your browser, hit Run, and watch real machine scenarios react. 12 guided lessons across 8 PLC dialects — free account, no credit card.

Practice PLCs free →