Industrial Engineer · phase 4 of 16
Timer (TON, TOF, TP)
IEC timer functions for on-delay, off-delay, and pulse timing.
The Explain card
- Plain English
- The three IEC timers answer three questions. TON turns its output on after the input has been true for the preset, TOF holds its output on for the preset after the input drops, and TP gives one pulse of the preset length whenever the input rises.
- Example
- A TON delays a conveyor start by three seconds after the button. A TOF keeps the cooling fan running thirty seconds after the heater stops. A TP fires a five second lube pulse each time a cycle begins.
- Why it matters
- Picking the wrong one produces a delay on the wrong edge, which looks like a random timing bug. Every timed behaviour on a machine is one of these three, so learn the picture for each.
- Hook
- Wait to start, linger after, or pulse once.
Where it sits in the deck
Phase 4: PLC Memory, Tags, and Instructions
The data a program moves and the instructions that move it, from a single true or false value up to a structured array.
