Pro
12 min

CCST 16 — Forced I/O and Override Risks

ccstdiagnosticsforceI/Ostuck
CCST 16 — Forced I/O and Override Risks scenario preview

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Briefing

Understand how I/O forcing works: you will force %I0.0 TRUE to simulate a stuck sensor and observe downstream effect. Then remove the force and verify normal operation.

Objectives

  • Identify a sensor that is stuck TRUE in the Variables tab
  • Determine the downstream output that is incorrectly energised
  • Describe how to safely remove an I/O force

Hints

  • Forced I/Os are marked with an F in Allen-Bradley; in this simulator use the Variables tab
  • Removing a force on an input allows the real field value to take over

I/O Table

Inputs

LEVEL_SENSOR

Level sensor (stuck HIGH)

BOOL · %I0.0

Outputs

FILL_VALVE

Fill valve output

BOOL · %Q0.0

Your program will be tested against:

All test cases run automatically when you submit. Assertions are hidden until you pass.

  1. #1Fill valve off when level high

    Fill valve off when level high

  2. #2Fill valve on when level low

    Fill valve on when level low

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