Computer Integrated Manufacturing

A: Governing principle: Presence-sensing safeguards only prevent motion when they can interrupt control power. Here, a jumpered light curtain still allows commanded motion, so it blocks neither unexpected starts nor high-speed traverse; it never addressed stored mechanical or electrical energy in the first place. Engineers often pick D because it's visible on the HMI, but that misapplies the safeguard’s scope to an energy isolation problem.

A: Governing principle: Throughput is set by total cycle time, not peak speed. Travel time is 120/1.5 ≈ 80 s; add 40 s handling gives ~120 s per pallet, or 30/hr, then trim for control delays to land near the mid‑20s. Option C traps people who forget to add fixed load/unload time after doing the distance math correctly.

A: Governing principle: Control loops tolerate latency poorly, planning layers tolerate it well. Here the PLC waits on MES confirmations, so added delay shows up as starvation; holding releases prevents oscillation while IT fixes latency. Option B appeals to those who know buffers help variability, but misapplies it across control layers where timing, not quantity, is failing.

A: Governing principle: Intermittent, resettable faults point to feedback, not force generation. Hydraulics show pressure is fine and a reboot clears the fault, aligning with a sensor dropping out mid-travel. Option D tempts those thinking mechanically, but a hard interference wouldn’t clear with a power cycle.