Lesson 9 — Delayed-Off (TOF)

Briefing

TOF (Timer OFF-delay) energises its Q output immediately when IN goes true, and keeps it on for PT after IN goes false. Classic application: an automatic door that opens when someone is present and stays open 5 seconds after they leave.

Objectives

• DOOR_OPEN goes true immediately when OCCUPANCY is true
• DOOR_OPEN stays true for 5 s after OCCUPANCY goes false
• DOOR_OPEN goes false 5 s after OCCUPANCY clears

I/O Table

Your program will be tested against:

All test cases run automatically when you submit. Assertions are hidden until you pass.

1. #1Door opens immediately on occupancy

   OCCUPANCY true → DOOR_OPEN true within one scan

2. #2Door stays open 2 s after occupancy clears

   OCCUPANCY goes false but DOOR_OPEN still true 2 s later

3. #3Door closes 5.5 s after occupancy clears

   DOOR_OPEN must be false 5.5 s after OCCUPANCY falls