Safety Light Curtain Mute Logic

Briefing

A light curtain guards the entry to a conveyor feed zone. Normally the curtain must be clear (unbroken) for the feeder to run. However, during an **eject cycle** the physics engine raises **MUTE_ACTIVE** — the muting window — which bypasses the curtain so product can pass through without stopping the line. Write the safety supervisory logic: 1. **SAFE_WINDOW** = CURTAIN_CLEAR OR MUTE_ACTIVE. 2. **3-wire seal-in**: START latches RUN_BIT; STOP or /ESTOP_OK resets it. START is only accepted when ESTOP_OK and SAFE_WINDOW are both true. 3. **FEED_RUN** = RUN_BIT AND ESTOP_OK AND SAFE_WINDOW. 4. **FAULT_LAMP** latches when: - ESTOP_OK goes false (E-stop tripped), OR - RUN_BIT AND NOT CURTAIN_CLEAR AND NOT MUTE_ACTIVE (beam break while running, no mute). Clears when ESTOP_OK is restored and the safety window is valid again.

Objectives

• SAFE_WINDOW := CURTAIN_CLEAR OR MUTE_ACTIVE
• 3-wire seal-in with ESTOP_OK and SAFE_WINDOW gate on START
• FEED_RUN := RUN_BIT AND ESTOP_OK AND SAFE_WINDOW
• FAULT_LAMP latches on E-stop trip or curtain break while running

I/O Table

Your program will be tested against:

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

1. #1Normal run: curtain clear + ESTOP_OK → FEED_RUN on

   With ESTOP_OK=true and CURTAIN_CLEAR=true, START latches run and FEED_RUN turns on.

2. #2E-stop trip → FEED_RUN off, FAULT_LAMP on

   While running, drop ESTOP_OK — FEED_RUN must go off and FAULT_LAMP must latch.

3. #3Mute active: beam break does not stop FEED_RUN

   When EJECT_CYCLE is true (MUTE_ACTIVE=true), a curtain beam break should NOT trip FEED_RUN.