TON Timer (On Delay Timer, or Delay Timer (TD))

Use this timer to delay turning an output ON. The TD Timer Out bit turns ON when the timer has finished running.

1. The Preset Value is initially loaded into the Current Value the first time that the TD element is seen in the program scan.

2. When the input condition of a TON timer rises (positive RLO), the Timer begins to decrement.

3. When the current value of the timer reaches 0, and the timer's input condition is still ON, the Timer Out bit turns ON.
   The Timer Out bit remains ON until the input condition falls (negative RLO).

4. When the input condition of the TON timer falls (negative RLO), the Preset Value is loaded into the Current Value.

If the input condition falls while the timer is running:

• The timer stops and reloads the Preset Value.
• The current value is not retained.
• The Timer Out bit remains OFF.
• When the input condition rises (positive RLO), the Timer begins to decrement from the Preset Value.