Which timer instruction continuously counts down while it is energized?

The Timer On Delay instruction is designed to start counting down once the associated input has been activated and remains energized. It continuously processes the timer's countdown as long as the input remains in the energized state, making it particularly useful for applications where a delay is needed before an action can occur after a condition is satisfied.

This type of timer does not reset until the input goes unenergized, allowing it to accurately measure the time delay needed in a process. Its design supports instances where a precise timing sequence must be maintained while the input is active, emphasizing its utility in various programmable logic controller (PLC) applications. This continuous countdown feature is essential for applications where maintaining a specific delay before action is critical, which sets it apart from other timer types that may not function in the same manner.