What triggers a hard shutdown (alarm) condition?

What triggers a hard shutdown (alarm) condition?

• A. One obstruction detected
• B. Two consecutive obstructions before reaching a limit position or before receiving a gate command
• C. Continuous obstruction
• D. No obstruction but alarm set

Answer: (B)

A safety interlock concept is being tested here: the system is designed to treat a real blockage as serious only when it’s shown across multiple checks, not from a single momentary occlusion. The hard shutdown (alarm) is triggered when obstruction is detected in two consecutive readings before the gate reaches its limit or before a gate command is actioned. This persistence criterion helps prevent nuisance alarms from brief or accidental occlusions, ensuring the gate only halts when there’s a real and ongoing blockage that could pose harm. If only a single obstruction is detected, it typically won’t cause the hard shutdown; the system may issue a warning or soft stop instead. A continuous obstruction or a configuration with the alarm set but no obstruction doesn’t match the specific triggering condition described, which relies on two consecutive obstruction events in the defined window.

A safety interlock concept is being tested here: the system is designed to treat a real blockage as serious only when it’s shown across multiple checks, not from a single momentary occlusion. The hard shutdown (alarm) is triggered when obstruction is detected in two consecutive readings before the gate reaches its limit or before a gate command is actioned. This persistence criterion helps prevent nuisance alarms from brief or accidental occlusions, ensuring the gate only halts when there’s a real and ongoing blockage that could pose harm.

If only a single obstruction is detected, it typically won’t cause the hard shutdown; the system may issue a warning or soft stop instead. A continuous obstruction or a configuration with the alarm set but no obstruction doesn’t match the specific triggering condition described, which relies on two consecutive obstruction events in the defined window.