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Practice missions
Mission 55 · Pro PLC programming exercise

Bay A to bay B

Position three crane axes from their encoders and move plates on a magnet.

In Auto, move every plate from bay A (−1.2, −0.7) to bay B (1.2, 0.7). Raise to 1.6 m before travelling, run each axis fast then slow, lower until contact, and grip or release with the magnet.

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The 3D overhead crane automation this mission runs on Pro mission
Test replay

Travel and pick at bay A

Test 1 of 3
Set by the testChecked by the testStep 11 of 11 · 1.1 s
Level
Advanced
Time
About 60 min
Reward
+750 XP
Rig
3D overhead crane automation
Siemens editors
SCL, LAD
Rockwell editors
Structured Text, Ladder
Course stage
29. Machine lab 4: safety sequences and plant control
Automatic tests

What the tests check

  1. Each axis runs fast, creeps inside 0.4 m and stops inside 0.01 m.
  2. Bridge and trolley only move with the hoist at 1.5 m or higher.
  3. Lowering creeps below 0.6 m and stops on Contact.
  4. The magnet stays on from gripping until the plate is resting at B.
  5. All plates end up in bay B.
  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

Automatic cranes in coil stores and steel yards do exactly this, around the clock, from encoder positions and a yard map.

Stopping from full speed overshoots by more than a hand's width; creeping all the way takes forever. Carrying a load low clips stacks; letting the magnet go early drops three tonnes.

Where you'd find thisPut three tonnes exactly where it belongs, and nowhere near people

Steel stockyards, mills and warehouses move heavy loads with overhead cranes. Automatic cranes position each axis from encoders: full speed for most of the move, a slow creep for the last few centimetres.

  1. RaiseClear everything
  2. TravelFast, then creepYou are here
  3. LowerUntil contact
  4. MagnetGrip or release
On a real site: places, parts and safety
  • Steel stockholders and coil stores
  • Paper reel and container yards
  • Automated warehouses and press shops

Loads are never carried over people: automatic cranes have exclusion zones and lock out when someone enters.

Cranes are covered by LOLER in the UK: a thorough examination every 12 months and a safe working load on the girder.

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

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