CCST 23 — Monitor Validated Light-Curtain Muting

Briefing

This exercise monitors a muting function that has already been validated and executed by a safety-rated controller or device. MUTE_AUTH represents that controller's active authorization after its configured muting-sensor arrangement, sensor sequence, timing window, maximum mute duration, discrepancy monitoring, and fault checks have passed. The ordinary PLC combines that status with MUTE_REQUEST only for process supervision and indication. It does not create, bypass, or reset the safety function. Real equipment requires a machine risk assessment and validation against the device manual and applicable safety standards.

Objectives

• MUTED is a non-safety indicator and is TRUE only when both MUTE_REQUEST and the prevalidated MUTE_AUTH status are TRUE
• SAFE_ZONE_CLEAR is a non-safety HMI status: TRUE when the curtain is not tripped or the validated mute indication is active
• CURTAIN_TRIPPED drops the supervisory SAFE_ZONE_CLEAR status when validated muting is not active
• The student logic must never be described or used as a safety output, safety function, or final-element control

I/O Table

Your program will be tested against:

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

1. #1Zone clear when curtain not tripped

   Zone clear when curtain not tripped

2. #2Zone clear when muted despite curtain

   Zone clear when muted despite curtain

3. #3No muting without auth

   No muting without auth

4. #4Validated authorization alone does not create a local mute request

   Curtain tripped, MUTE_AUTH true, request false -> supervisory outputs remain off