How does a limit switch allow event sequencing?

• A. They speed up the next event
• B. Limit switches start the next event in a sequence only after the prior event is complete
• C. They maintain constant voltage for the next cycle
• D. They disable the machine until manual reset

Answer: (B)

Event sequencing relies on a clear feedback signal that tells the control system when a current action has finished and it’s time to move to the next one. A limit switch provides that signal by changing its contact state when a moving part reaches a predefined position or end of travel. When the switch’s contact changes, the controller receives a definite on/off input and starts the next operation only after the prior motion has completed. This keeps steps in the correct order, prevents overlapping motions, and adds a safety check that the part is in the proper position before advancing.

The other ideas don’t fit because a limit switch isn’t about speeding up the next event, maintaining voltage, or forcing a manual reset. It’s about giving a precise, position-based signal to sequence actions reliably.