From the course: Learning PLC Ladder Logic: 1 The Basics

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Timer types (TON and TOF) and diagrams

Timer types (TON and TOF) and diagrams - Ladder Logic Tutorial

From the course: Learning PLC Ladder Logic: 1 The Basics

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Timer types (TON and TOF) and diagrams

- The main two types of timers are, Timer ON Delay and Timer OFF Delay. And it's usually written on the timer instruction, what type of timer that is. Timer On Delay instruction, usually use to turn on an output, on or off after the timer has been on for a preset value. So let's take an example of a Timer On Delay that is set for 20 second. And, we use an input like a switch. I'm going to use a timer diagram, in order to explain the concept and to show the difference between the two timer types. This is the time diagram for the Rung. It goes from False to True. And if we have an input in the Rung, like in our case we have a switch, then when the input is True the Rung is True. This is showing how long the Rung is being True, or how long we have kept this switch on. Let's say that the Rung stays on for 40 seconds. Whenever the Rung is True, the Enable bit becomes True as long as the Rung is on. The timer is set to time for 20 seconds, so the timer is timing for 20 seconds only. This…

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