Industrial Engineer · phase 4 of 16 · noun
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.
Word knowledge
How the word is built, where it came from, and what it sits beside in memory.
In a sentence
The PLC Timer starts when the conveyor photoeye turns on and sets a done bit after five seconds.
How it is built
- time root to measure or regulate duration
- -er suffix a person, device, or function that performs an action
Where it came from
- Origin
- English time combined with the instrumental suffix -er
- Entered the language
- 1820s
- What changed
- It developed from a general name for a timekeeper or time-measuring device into a standard control-programming term.
How it is spelled
- Pattern
- The final silent e in time is dropped before the vowel-initial suffix -er.
Spelled like
- writer
- rider
- driver
Broken into chunks
-
time
- timed
- timing
- timekeeper
-
-er
- counter
- recorder
- controller
What it sits beside
Same subject
- preset value
- elapsed time
- done bit
- ladder logic
Same shape
- writer
- rider
- driver
IEC timer instruction names
- TON
- TOF
- TP
timer data terms
- preset
- elapsed time
- output bit
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.
