Light Curtain Muting Logic Simulation

Briefing

This training simulation demonstrates the observable sequence and timing concepts used by one example of two-sensor light-curtain muting. It is not a safety function or deployable machine-safety program. On real equipment, muting must be configured in a safety-rated controller or device using the manufacturer-approved sensor arrangement, required sequence, timing and maximum mute duration, discrepancy and fault monitoring, guarded reset, and validation derived from the machine risk assessment. Here, LIGHT_CURTAIN_OK, MUTE_A and MUTE_B let you study expected behaviour: A then B within 2 seconds creates the simulated mute window; simultaneous, reversed, or late activation creates a simulated fault.

Objectives

• MACHINE_ENABLE is on while LIGHT_CURTAIN_OK is true and no fault is latched
• Beam break (LIGHT_CURTAIN_OK = false) without valid muting → latch SAFETY_FAULT_LATCH
• Valid mute: MUTE_A then MUTE_B, ≥50 ms apart, within 2 s — MUTE_LAMP asserts during the muted window
• MUTE_LAMP stays on as long as both mute sensors are active and the sequence was valid
• Invalid mute (simultaneous, reversed, or timeout) → latch SAFETY_FAULT_LATCH
• RESET_PB clears SAFETY_FAULT_LATCH only when LIGHT_CURTAIN_OK is true and no mute is active
• Treat every output as a training signal only; a safety-rated device must control real safety outputs and final elements after risk assessment and validation

I/O Table

Your program will be tested against:

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

1. #1Machine enables when curtain OK and started

   With LC clear and START_PB, MACHINE_ENABLE asserts and no fault

2. #2Beam break without muting latches SAFETY_FAULT_LATCH

   LC blocked with no valid mute → fault latches; releasing LC does not clear

3. #3Valid mute sequence allows curtain block without fault

   MUTE_A then MUTE_B within 2s, then LC blocked — no fault, MUTE_LAMP on

4. #4Simultaneous MUTE_A + MUTE_B latches fault

   Both mute sensors asserted at same time is an invalid mute — fault latches

5. #5MUTE_B before MUTE_A latches fault

   Reversed order is an invalid mute — SAFETY_FAULT_LATCH must latch