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Mission 69 · Pro PLC programming exercise

Commission the cell

Bring every safety rule together: two-channel devices, both stop categories, muting and contactor checks.

Write the whole cell: a two-channel E-stop (category 0), a two-channel gate (category 1), a muted light curtain (category 1), discrepancy and contactor checks, and a deliberate reset and start.

Training only. This is not a certified safety system. On a real machine these rules run in a safety relay or a safety PLC, designed and validated to ISO 13849-1 or IEC 62061.

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The 3D robot safety cell this mission runs on Pro mission
Test replay

Run, and let a carton through

Test 1 of 6
Set by the testChecked by the testStep 13 of 13 · 1.5 s
Level
Expert
Time
About 75 min
Reward
+900 XP
Rig
3D robot safety cell
Siemens editors
Ladder (LAD), SCL
Rockwell editors
Ladder, Structured Text
Beckhoff editors
Structured Text
Course stage
35. Safety capstone: commission the cell
Automatic tests

What the tests check

  1. E-stop or any fault: power off at once (category 0).
  2. Gate or an unmuted curtain break: brake, then power off at Standstill or after 1 s (category 1).
  3. Cartons pass the curtain muted; people do not.
  4. Channel and contactor faults , light FaultLamp and block the reset.
  5. Nothing restarts without a fresh Reset and then a fresh Start.
  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

Commissioning a cell means proving every safety function, one device and one fault at a time, and writing the result down.

Each device on its own is simple. Together, one rule can quietly undo another: a reset that clears a fault, or muting that outlives its carton. Only a full test of every case shows the cell is right.

Where you'd find thisKeep people out while the arm moves, and prove it every time

A robot stacks cartons inside a fence. A gate lets a fitter in, a light curtain lets the cartons in, and an emergency stop sits outside. Two contactors in a row cut the robot's power, so one that sticks cannot keep it running.

  1. InfeedCartons through the curtain
  2. PickRobot takes the carton
  3. GuardStop, reset, restartYou are here
  4. PalletSix cartons, then change
On a real site: places, parts and safety
  • Robot palletising and packing cells
  • Machine tending: robots loading presses and machine tools
  • Any guarded machine with a door, a curtain or an E-stop

Training only: this rig is not a certified safety system. Real safety functions run in safety relays or a safety PLC, designed and validated to ISO 13849-1 or IEC 62061.

IEC 60204-1 sets out stop categories 0, 1 and 2 and how an emergency stop must behave. Which category a machine uses comes from its risk assessment.

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

Keep going

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