Human-System Interface and Control Room Design
Core concepts
Interface design should fit human perception and action. Know affordances and mapping (controls arranged to match process layout), compatibility (movement and display direction consistent with expectation), population stereotypes, and stimulus-response compatibility. Understand grouping and proximity principles, coding (colour, shape, position, label), and the dangers of colour-only coding for colour-vision-deficient users.
Alarm management is central: alarm flood, nuisance alarms, prioritisation, and first-out identification. Displays should support level 1-2-3-4 abstraction (overview, then detail), avoid clutter, and show trends and limits. Mode awareness and clear feedback prevent errors with automated systems. Consider control-room ergonomics: sightlines, lighting, glare, noise, seating, and reach zones. Human-centred design iterates with users and validates against tasks, not just specifications.
Traps in questions
- Assuming a modern digital interface is inherently safer; poor integration can worsen workload.
- Ignoring that colour coding alone fails accessibility and degrades under stress or lighting.
- Confusing alarm rationalisation (removing or re-prioritising) with simply suppressing alarms.
- Forgetting that physical layout mapping aids performance more than decorative symmetry.
- Treating design as purely aesthetic rather than task-driven.
Worked rule of thumb
Apply the glance test: can an operator, in one glance, tell what the plant is doing, whether it is safe, and what to do next? If not, the overview layer is failing. Example: a mimic with hundreds of equally bright indicators fails the test; a hierarchical display with a clear safety-critical summary passes. Use this to evaluate proposed redesigns in exam scenarios.