⏱️ The Suspiciously Fun PLC Series · Track 05The Scan Cycle:
The Scan Cycle:
how a PLC really runs.
Before timers, before OOP, before anything — there's the loop. A PLC doesn't run your code top-to-bottom once like a script. It reads every input, runs your whole program, writes every output, and does it all again thousands of times a second. Get this mental model and the rest of PLC programming finally clicks.
The Loop
🔄 Read → run → write, forever · 📸 the process image (why inputs are a snapshot).
Timing & Memory
⏱️ cycle time & the watchdog · 🧵 tasks & priorities · 🔋 what survives a reboot.
The anchor for the whole Academy — every other track quietly assumes this loop.