Which of the following is an example of a limit switch being used in a single-cycle cylinder reciprocation circuit?

• A. A punch press
• B. A conveyor belt system
• C. A robotic arm
• D. A temperature sensor

Answer: (A)

Limit switches in a single-cycle cylinder reciprocation circuit serve as end-of-travel detectors that tell the controller when the cylinder has reached the end of its stroke and needs to stop or reverse. In a punch press, the ram must move forward to punch and then return to the starting position for the next cycle. Placing a limit switch at the end of the stroke gives a precise, reliable signal that forward motion is complete and triggers the return, creating a clean, repeatable one-cycle operation.

Other systems don’t fit this pattern: a conveyor belt runs continuously and uses sensors suited for continuous position or item detection rather than end-of-stroke stopping; a robotic arm involves multiple axes and more complex sensing; a temperature sensor is used for measuring heat, not controlling a cylinder’s end-of-travel position.