Learn PLCs free
Ladder Logic ElementsAdvancedAdvanced
1 min read
Updated 2025-11-10
Advanced

Sequencer Compare

SQC - Sequencer Compare

Compares input pattern with stored patterns for sequence verification.

Key Takeaways

  • Compares input pattern with stored patterns for sequence verification.
  • Advanced-level topic in Ladder Logic Elements

Detailed Definition

Compares input pattern with stored patterns for sequence verification. This term is essential for understanding ladder logic in industrial automation and PLC programming.

Ladder logic relies on Sequencer Compare as part of the small set of primitives that combine into every conceivable PLC program. Compares input pattern with stored patterns for sequence verification.

Inside the scan cycle, Sequencer Compare is processed during the program execution step. Its behaviour is deterministic — given the same inputs, it always produces the same outputs in the same time — which is exactly what industrial control demands.

Mastering Sequencer Compare is part of becoming productive in ladder logic — the language in which roughly 80% of industrial automation is still written. Visual readability is the reason ladder hasn't been displaced; engineers continue choosing it for binary logic and machine sequencing.

Common Questions

What is Sequencer Compare?

Compares input pattern with stored patterns for sequence verification.

What prerequisites are needed to understand Sequencer Compare?

As an advanced-level concept, Sequencer Compare requires a solid foundation in PLC fundamentals and intermediate programming concepts. It's recommended to have hands-on experience with Ladder Logic Elements before diving deep into this topic.

What are related concepts I should learn?

To fully understand Sequencer Compare, you should also familiarize yourself with TON (Timer On-Delay), TOF (Timer Off-Delay), and CTU (Count Up). These concepts work together in industrial automation systems.

Was this helpful?

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

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

Quick Info

Difficulty
Advanced
Tier
Advanced

About Ladder Logic Elements

Contacts, coils, timers, counters, and ladder diagram components

Total Terms:70
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 →