PLC lab · Level 4 of 8
Batch counter on a packing line
Level 4 of 8 in the PLC lab: a free PLC exercise at Foundation level, which takes about 45 minutes. Count boxes past a photo-eye once each, stop at the batch size, and survive a backed-up line.
Free · no download · about 45 minutes. Your work is saved on this device. Updated 18 Oct 2026.
The brief
- Client
- Greenvale Foods
- Site
- Case conveyor CV-12
- Work order
- GF-2604
- Industry
- Food and drink
- Task code
- PLC-04
- Difficulty
- Foundation
- Type of work
- Programming
Count boxes past a photo-eye, stop the conveyor when a batch is complete and reset for the next batch, counting each box once however long it blocks the eye.
What you do
- Read the client brief and the tag table: 6 tags, 4 inputs and 2 outputs.
- Write the logic in ladder, Structured Text or SFC.
- Press Simulate and watch the plant answer your program.
- Run the factory acceptance test and fix what fails.
Skills you practise
- CTU counters
- Rising-edge detection
- Counter reset
- Seal-in circuits
What the test checks
The factory acceptance test runs 5 numbered tests against your program. The numbers in the brief are drawn per learner. The tests are:
- Start and Stop run the conveyor
- Stops after exactly 8 boxes and lights Batch done
- A box that stops in the beam counts once
- Stopping part way keeps the count
- Start is locked out until Reset, and Reset starts a fresh batch
In this lab
- Ladder, Structured Text and SFC in one studio
- A plant that answers: motors, tanks, conveyors
- Numbered tests mark your program
Levels in the PLC lab
Part of the PLC lab
Program a working machine in ladder, Structured Text or SFC and watch it run.
Feeds these internships: PLC Programming.