Industrial Engineer · phase 3 of 16
Periodic Task
Task scheduled to run at a configured time interval.
The Explain card
- Plain English
- A periodic task runs on a fixed schedule, every so many milliseconds, whatever else is going on. The controller interrupts lower priority work to keep the period.
- Example
- A flow totalizer that integrates a rate every 100 milliseconds lives in a 100 millisecond periodic task. The math is right because the interval is exactly what the code assumes.
- Why it matters
- Fixed rate logic, PID loops and anything that counts time by counting executions belong here. A period set shorter than the task's own execution time overlaps itself and faults the controller.
- Hook
- Runs on the clock, and only on the clock.
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.
