How to play
Goal: program the PLC so the machine does what the level asks, then press Verify. Using fewer instructions earns more stars (wires and branches are free).
- Pick an instruction (1–9), choose its address and preset, then click a cell. Clicking a filled cell replaces it, and gaps to its neighbours are wired for you.
- Drag with Wire or Erase (0) to paint several cells. Right-click erases one cell.
- Branch links a cell's right edge down to the next rung. Use it for parallel contacts (OR) and self-holding latches.
- Hold the push buttons on the operator panel and click the switches. Sensors are driven by the plant.
- Keyboard: arrow keys move in the editor, Enter places, Del erases, Ctrl+Z undoes.
The CPU runs a real scan cycle every 10 ms: it reads the inputs, solves the rungs left to right and top to bottom, then writes the outputs. Green wires carry power, and green contacts are true.