A palletizer with vacuum cups picks up a case and positions it on a waiting pallet. A limit switch detects what?

In the context of a palletizer using vacuum cups, a limit switch plays a crucial role in the automation process. The correct answer focuses on the function of the limit switch, which is to detect the presence of cases at a specific position in the system, typically at the end of the conveyor line.

When the vacuum cups pick up a case and transfer it, the limit switch ensures that the case has successfully arrived at its intended destination on the pallet. This detection is essential for the control system to confirm that the placement has occurred correctly before the next operation can take place, such as picking up another case or completing the stacking process.

By confirming that the case is where it needs to be, the limit switch provides feedback that facilitates the smooth operation of the entire palletizing process. This function is important for maintaining proper workflow and aligns with the operational needs of the automated system.

In contrast, the other options focus on different aspects of the palletizing operation that do not align with the primary function of a limit switch, which is primarily to detect presence or absence at a certain point in the system rather than measuring time, counting, or gauging weight.