Industrial Engineer · phase 3 of 16
Interlock
Logic that prevents an operation when a condition would make it unsafe or damaging.
The Explain card
- Plain English
- An interlock is logic that blocks an action while some condition would make it dangerous or damaging. It sits in series with the command and wins every time.
- Example
- The press cannot cycle while the light curtain is broken. The curtain's clear bit is a contact on the cycle rung, and no operator input gets around it.
- Why it matters
- Interlocks are how the program encodes what the machine must never do. They belong in one obvious place per output, so a technician can find every reason a motor will refuse to run without reading the whole project.
- Hook
- The reasons the machine says no.
Where it sits in the deck
Phase 3: PLC Program Organization and Execution
How the logic is arranged and how the scan actually runs it, which is the difference between code that works and code that works every time.
