Industrial Engineer · phase 4 of 16
Retentive Timer
Timer that preserves accumulated time until a reset instruction clears it.
The Explain card
- Plain English
- A retentive timer keeps its accumulated time when its input goes false. It picks up where it left off when the input returns, and only a reset instruction clears it.
- Example
- A filter needs changing after 100 hours of running. A retentive timer counts only while the pump runs, across dozens of starts and stops, and flags maintenance when it reaches the preset.
- Why it matters
- A plain timer starts over every time the input drops, so it can never total intermittent time. The retentive one needs an explicit reset, and forgetting that reset means it trips once and never again.
- Hook
- A stopwatch that pauses instead of resetting.
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.
