Motion 01 — Encoder distance

Briefing

A belt carries parts to a station. An incremental encoder on the drive roller sends one pulse (ENC_PULSE) for every 10 mm the belt moves, so the PLC can measure distance by counting pulses. It only pulses while the belt is really moving. Tap START and the belt runs. Count the pulses with a counter; when the belt has moved 200 mm it must stop and AT_TARGET must light. Work out how many pulses 200 mm is. STOP pauses the belt without losing the count, so START carries on to the same 200 mm mark. RESET clears the count so the next move can begin.

Objectives

• START runs the belt (BELT_RUN stays on after the button is released)
• The belt keeps running until 200 mm of travel has been counted
• At 200 mm the belt stops and AT_TARGET lights
• STOP pauses the belt without clearing the count
• RESET clears the count so a new move can start

I/O Table

Your program will be tested against:

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

1. #1Tap START → belt runs, target lamp off

   A momentary START latches the belt on

2. #2After 3.6 s (about 170 mm) → still running

   The count has not reached the target yet

3. #3After 4.6 s → stopped at 200 mm, target lamp on

   Twenty pulses stop the belt and light AT_TARGET

4. #4STOP during the move → belt off and stays off

   STOP switches the belt off without lighting the target lamp

5. #5STOP then START → carries on to the same 200 mm mark

   STOP does not clear the count

6. #6RESET clears the count → target lamp off, START runs again

   RESET reaches the counter and a new move can begin