Pneu 02 — Cylinder sequence

Briefing

A clamp and a stamp. Cylinder A holds the part, cylinder B stamps it. Each has a 5/2 valve with two solenoids (EXTEND and RETRACT) and two reed switches (home and fully out). With neither or both solenoids on, a cylinder simply holds position. One tap of START runs the sequence A out, B out, B back, A back. Each move starts only when the sensor of the move before it closes: the machine never guesses with a timer. Only one cylinder moves at a time, and A stays clamped out while B stamps. STOP drops every solenoid and clears the sequence. The valves have no springs, so the cylinders stay where they are; use the simulator's Reset button to send the machine home. START mid-cycle does nothing.

Objectives

• START extends A alone
• When A is fully out, B extends while A stays out
• When B is fully out, B retracts while A stays out
• When B is home, A retracts; then everything is off
• STOP ends the cycle at any moment; START mid-cycle is ignored

I/O Table

Your program will be tested against:

All test cases run automatically when you submit. Assertions are hidden until you pass.

1. #1START → A extends alone

   The first move is A out; B waits

2. #2A fully out → B extends

   A's extended sensor starts the second move

3. #3B fully out → B retracts, A stays out

   B comes home first while A stays clamped

4. #4B home → A retracts

   B being home starts the last move

5. #5A home → everything off

   The last sensor ends the cycle

6. #6STOP during B's stroke → everything off, and stays off

   STOP ends the cycle at any step

7. #7START while A is returning → one cycle only

   START only begins a cycle when both cylinders are home and no move is active

8. #8START after a finished cycle → A extends alone

   A second cycle starts cleanly