The on-delay timer (TON) starts timing when the timer's:

A) ladder rung switches from false to true.
B) ladder rung switches from true to false.
C) accumulated value equals its preset value.
D) accumulated value is greater than its preset value.

On-Delay Timer

An electromechanical relay with contacts that change state a predetermined time period after the coil is energized; the contacts return to their shelf state immediately on de-energization of the coil; also, a programmable logic controller instruction that emulates the operation of the electromechanical on-delay timer.

Ladder Rung

A horizontal section of a ladder logic diagram, representing a specific logic operation in PLC programming.