What is the critical procedure to follow before performing any maintenance on the electrical system of an industrial robot?

The critical procedure to follow before performing any maintenance on the electrical system of an industrial robot is to completely de-energize and lockout/tagout (LOTO) the robot. De-energizing means disconnecting the robot from all sources of electrical power, including the main power supply and any backup power sources. Lockout/tagout is a safety procedure that involves physically locking the power disconnect switch in the 'off' position and attaching a tag to the switch indicating that maintenance is in progress and the power should not be turned on. This prevents accidental energization of the robot during maintenance, which could cause electric shock, burns, or other serious injuries. For example, before replacing a faulty circuit board in the robot controller, the technician would first disconnect the robot from the main power supply, lock the disconnect switch with a padlock, and attach a tag with their name and the date. This ensures that no one can accidentally turn the power back on while the technician is working on the electrical system. It's also essential to verify that the robot is indeed de-energized using a voltage tester before starting any work. The lockout/tagout procedure must comply with relevant safety standards and regulations to ensure worker safety.