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Challenge 14 · Find the fault · Pro

The transfer that flooded the wash room

Two levels, actuator feedback, a coasting motor and a latched trip.

Repair a complete transfer controller. Open the route before pumping, stop at the receiving target, and protect the source.

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The 3D two-tank transfer rig this challenge runs on Pro challenge
Test replay

Open before pumping; coast before closing

Test 1 of 7
Set by the testChecked by the testStep 11 of 11 · 460 ms
Level
Hard · 40 points
Kind
Find the fault
Time
About 45 min
Pass rate
New
Machine
3D two-tank transfer rig
Siemens
SCL
Rockwell
Structured Text
Beckhoff
Structured Text
The operator’s report · two-tank transfer rig
The motor started while the valve was still moving. A full receiver overflowed. Restoring permission restarted a transfer without another press.
Automatic checks

What the checks test

  1. Open feedback gates the pump; a missing signal gets a fresh 500 ms timeout.
  2. Stop at 80%, keep the route open while the motor coasts, then close it.
  3. Dry source, lost permission and faults a trip; recovery needs a fresh Start.

The checks run 7 tests on the machine, scan by scan: Open before pumping; coast before closing; Dry-source priority beats completion and Reset; Open feedback timeout boundary; Lost feedback removes pump immediately and times a fresh wait; Held Start cannot restart on restored permission; Stop and physical failure are immediate; Cannot begin with no room or no water.

On site

Where you’d find this

A factory wash tank is refilled from a bigger storage tank. The valve must be open before the transfer pump starts.

A pump that runs with no water can ruin its seal. Overfilling the wash tank spills water onto the floor.

The machine

How it should behave

Start and phase
State 0 is idle. A fresh Start with Permit, no Fault/PumpDamaged, SourceLevel > 10% and Level < 80% enters 10. ValveCmd opens the route; PumpOn stays OFF until ValveOpen enters 20. Process one phase transition per scan.
Feedback timeout
In 10 or 20, missing ValveOpen continuously for 500 ms trips to 90. The first enabled Delay invocation starts at zero. Returning feedback resets the wait. In 20, PumpOn must turn OFF immediately whenever ValveOpen is FALSE.
Full receiver and coast
Level >= 80% enters 30: PumpOn OFF, ValveCmd still ON. Wait for MotorSpeed <= 0 rpm before 50, closing ValveCmd and setting Done. DrainValve remains OFF throughout. Ordinary entry commands may lag State by one scan; entry to 30 removes PumpOn immediately.
Trip and recovery
In active states, lost Permit, Fault, PumpDamaged or SourceLevel <= 10% wins over completion and immediately enters 90: Alarm ON, PumpOn/ValveCmd/Done OFF. Stop returns to 0 unless already tripped. Reset clears 50/90 only with Start released, Permit, no Fault/PumpDamaged and SourceLevel > 10%. Restoration cannot restart without a fresh Start.
Physical evidence
SourceLevel measures a 400 L tank; Level measures a 100 L receiver. FlowRate is actual transfer. PumpWear and SpilledLitres show consequences. Dry or blocked pumping accumulates illustrative wear; full wear stops the shaft. These are teaching effects, not real damage predictions or safe limits.

Run and briefly press Start. Watch the source fall and receiver rise. Select the transfer valve to compare command and travel. Set ValveStuck before a fresh run to test the opening timeout.

Keep going

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