Lighting: Lighting Panels

Question 1

A complex motor control system uses multiple interlocked contactors to reverse a conveyor motor. Occasionally, both forward and reverse contactors energize simultaneously during a PLC program change. Which engineering control is most appropriate to prevent this hazard?

Question 2

During commissioning, a lighting control panel is not energizing some relay-controlled lighting circuits even though the panel has power. What is an appropriate first troubleshooting step?