Example — Codesys Sfc
[Step 20: DIP] --(45s & no EStop)--> [Step 30: RINSE] | | (EStop_Pressed) v [Step 99: EMERGENCY_RETRACT] --(Acid_Level<5%)--> [Step 0: IDLE] Inside Step 99 's Action:
The Pickle Paradox System: Industrial Pickling Line (Acid Bath for Steel Coils) Controller: CODESYS SoftPLC v3.5 SP20 Part 1: The Problem Engineer Lena Vasquez stared at the production log. Line 7, the steel coil pickling line, had just scrapped its third $40,000 coil of the week. The sequence: Load coil → Dip in HCl acid → Rinse → Dry → Unload .
She added a parallel to the main sequence: codesys sfc example
Then she wrote a parallel :
The problem was chaos. Operators would skip steps, hit "EMERGENCY RESET" mid-dip, or manually open the drain while the coil was submerged. The old ladder logic was a 40-rung monster of interlocking seals that no one understood. [Step 20: DIP] --(45s & no EStop)--> [Step
Lena shook her head. "No. We need an SFC." She opened CODESYS and created a new POU (Program Organization Unit). She chose Sequential Function Chart (SFC) . No ladder. No structured text loops. Just pure, visual, time-tested sequence logic.
But then... nothing.
The SFC jumped to Step 99. The crane rose. The drain opened.
