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Mission 50 · Pro PLC programming exercise

25 kg, every sack

Feed fast, then slow, stop early, and learn from every batch.

Weigh 25 kg batches within ±0.1 kg: fast feed to 3 kg short, slow feed to the in-flight point, settle, check, discharge. Learn the in-flight from each batch.

This mission is part of ProTry the full course, every mission and the expert challenges free for 7 days. No card needed.
The 3D batch weighing system this mission runs on Pro mission
Test replay

One batch, in tolerance

Test 1 of 3
Set by the testChecked by the testStep 13 of 13 · 2.2 s
Level
Advanced
Time
About 40 min
Reward
+500 XP
Rig
3D batch weighing system
Siemens editors
SCL, LAD
Rockwell editors
Structured Text, Ladder
Course stage
28. Machine lab 3: measurements and batches
Automatic tests

What the tests check

  1. Fast feed to Target − 3.0 kg, then slow feed.
  2. Slow feed stops at Target − Inflight.
  3. The batch is judged only after 1.5 s of settling.
  4. Inflight learns half of each batch's error.
  5. The gate opens to empty the hopper, and the next batch waits for it to close.
  1. Try it Use the buttons below the model and watch the rig respond.
  2. Test solution Every check runs on your code in one press.
  3. Replay If one fails, step through it one scan at a time to see why.
Why it matters

Where you’d see this on site

Every bag of flour, cement or pet food was filled by a weigher like this, usually learning its in-flight automatically.

Short weight is illegal; overfilling a few grams per sack gives away tonnes of product a year. In-flight changes with the material, so a fixed figure drifts out of tolerance.

Where you'd find thisHit the weight every time, including what is still in the air

Food, chemicals and building products are packed by weight. A feeder runs fast, then slow, and stops early because product is still falling when it stops. Good controllers learn how much from every batch.

  1. SupplyHopper and screw
  2. WeighFast, slow, settleYou are here
  3. DischargeClamshell gate
  4. Sack25 kg
On a real site: places, parts and safety
  • Packing lines for flour, sugar, cement and feed
  • Ingredient batching in food and pharma
  • Plastics plants dosing granules and colour

Trade weighing is legal metrology: a packed sack must not be short, and the scale must be verified.

Dust from granules can be explosive: the hopper is extracted and earthed.

The sizes, timings and cutaways are teaching choices, not a drawing of any one real installation.

Keep going

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