HMI screen layout principles in SCADA systems - Practice Problems & Coding Challenges

Challenge - 5 Problems

🧠 Conceptual

intermediate

Understanding HMI Screen Layout Focus

Which principle best describes the main goal when designing an HMI screen layout?

A Use as many colors and fonts as possible to attract attention

B Maximize the number of controls on one screen to reduce navigation

C Organize information clearly to support quick operator decisions

D Place all alarms and controls randomly to test operator alertness

💡 Hint

Think about what helps operators work efficiently and safely.

The main goal of HMI screen layout is to organize information clearly so operators can make quick and accurate decisions. Overcrowding or random placement can confuse users.

✅ Best Practice

intermediate

Best Practice for Alarm Display on HMI Screens

What is the best practice for displaying alarms on an HMI screen to ensure operator awareness?

A Group alarms by priority and use consistent colors for severity

B Display only the most recent alarm and hide older ones

C Show all alarms in one list without priority or grouping

D Use flashing text for all alarms regardless of importance

💡 Hint

Consider how to help operators quickly identify critical issues.

Grouping alarms by priority and using consistent colors helps operators quickly identify and respond to the most important issues.

❓ Configuration

advanced

Configuring Navigation Buttons for HMI Screens

You want to configure navigation buttons on an HMI screen to improve usability. Which configuration is best?

SCADA systems

Button1: Go to Main Screen
Button2: Go to Alarm Screen
Button3: Go to Settings
Button4: Go to Reports

A Scatter navigation buttons randomly around the screen edges

B Place navigation buttons at the bottom center of the screen with clear labels

C Hide navigation buttons and use keyboard shortcuts only

D Place navigation buttons in the top left corner stacked vertically without labels

💡 Hint

Think about where users expect to find navigation controls.

Placing navigation buttons at the bottom center with clear labels is a common and user-friendly layout that supports easy access and understanding.

❓ Troubleshoot

advanced

Troubleshooting Poor HMI Screen Readability

An operator reports that the HMI screen is hard to read due to color choices. What is the most likely cause?

A Using consistent color coding for alarms

B Using only black and white colors

C Using large fonts and simple icons

D Using low contrast colors for text and background

💡 Hint

Think about what affects visibility and clarity on screens.

Low contrast between text and background colors makes it difficult to read information on the screen, reducing usability.

🔀 Workflow

expert

Optimizing HMI Screen Workflow for Operator Efficiency

Which workflow design best supports efficient operator interaction on an HMI system?

A Design screens with a logical flow from overview to detailed controls, minimizing clicks

B Design all controls on one screen to avoid switching screens

C Design screens with random control placement to keep operators alert

D Design screens that require multiple confirmations for every action

💡 Hint

Consider how operators move through tasks smoothly.

A logical flow from overview to detailed controls reduces operator effort and errors by minimizing unnecessary navigation and clicks.

Practice

1. What is the main purpose of grouping related items together on an HMI screen?

easy

A. To make the screen look more complex

B. To make the screen easier to understand and use

C. To increase the number of buttons

D. To use more colors on the screen

Solution

1. Step 1: Understand grouping concept

   Grouping related items helps users find information quickly and reduces confusion.

2. Step 2: Consider user experience

   A clear layout improves safety and efficiency by making controls intuitive.

3. Final Answer:

   To make the screen easier to understand and use -> Option B

4. Quick Check:

   Grouping = Easier use [OK]

Hint: Group related controls for clarity and ease [OK]

Common Mistakes:

• Thinking more colors always improve clarity
• Adding too many buttons without grouping
• Ignoring user navigation needs

2. Which of the following is the correct way to label buttons on an HMI screen?

easy

A. Use clear, descriptive text like 'Start Pump 1'

B. Use vague terms like 'Start' without context

C. Use only icons without any text

D. Use random colors without meaning

Solution

1. Step 1: Identify labeling best practice

   Clear, descriptive labels help users understand button functions immediately.

2. Step 2: Avoid vague or confusing labels

   Labels like 'Start Pump 1' are better than generic or icon-only labels for clarity.

3. Final Answer:

   Use clear, descriptive text like 'Start Pump 1' -> Option A

4. Quick Check:

   Clear labels = Better understanding [OK]

Hint: Use clear text labels, not vague or icon-only [OK]

Common Mistakes:

• Using unclear or generic button names
• Relying only on icons without text
• Ignoring color meaning in labels

3. Consider this HMI screen layout code snippet:

screen = {
  'title': 'Main Panel',
  'buttons': [
    {'label': 'Start', 'color': 'green'},
    {'label': 'Stop', 'color': 'red'},
    {'label': 'Reset', 'color': 'yellow'}
  ]
}

What is the main issue with this layout?

medium

A. Button colors do not match their typical meanings

B. Button labels are too descriptive

C. The screen title is missing

D. There are too many buttons

Solution

1. Step 1: Analyze button colors and meanings

   Green for 'Start' matches (go/action), red for 'Stop' matches (danger/stop), but yellow for 'Reset' does not--yellow typically means caution/warning, not reset.

2. Step 2: Confirm other options

   Labels are simple (not too descriptive), title present, few buttons--issue is color mismatch.

3. Final Answer:

   Button colors do not match their typical meanings -> Option A

4. Quick Check:

   Colors should match meaning [OK]

Hint: Match button colors to their common meanings [OK]

Common Mistakes:

• Ignoring color conventions
• Assuming more buttons are always bad
• Overlooking screen title presence

4. You notice an HMI screen is cluttered with many controls and colors. What is the best way to fix this?

medium

A. Remove all labels to save space

B. Add more colors to differentiate controls

C. Group related controls and reduce color usage

D. Increase screen brightness

Solution

1. Step 1: Identify clutter causes

   Too many controls and colors make the screen confusing and hard to use.

2. Step 2: Apply layout principles

   Grouping related controls and limiting colors improves clarity and usability.

3. Final Answer:

   Group related controls and reduce color usage -> Option C

4. Quick Check:

   Less clutter = Better usability [OK]

Hint: Group controls and limit colors to reduce clutter [OK]

Common Mistakes:

• Adding more colors increases confusion
• Removing labels reduces clarity
• Changing brightness does not fix layout

5. You need to design an HMI screen for a complex system with many controls. Which approach best follows good layout principles?

hard

A. Use flashing colors to attract attention to all controls

B. Put all controls on one screen with random colors for each

C. Use only icons without labels to save space

D. Create multiple screens grouping related controls and use consistent colors

Solution

1. Step 1: Understand complexity management

   Complex systems require breaking down controls into manageable groups to avoid overwhelming users.

2. Step 2: Apply layout best practices

   Using multiple screens with grouped controls and consistent colors improves navigation and safety.

3. Step 3: Avoid poor practices

   Random colors, icon-only labels, and flashing colors cause confusion and reduce usability.

4. Final Answer:

   Create multiple screens grouping related controls and use consistent colors -> Option D

5. Quick Check:

   Group + consistent colors = Best design [OK]

Hint: Use multiple grouped screens with consistent colors [OK]

Common Mistakes:

• Trying to fit all controls on one screen
• Using random or flashing colors
• Relying only on icons without text