HMI screen design basics in PLC Programming - Cheat Sheet & Quick Revision

Recall & Review

beginner

What does HMI stand for in industrial automation?

HMI stands for Human-Machine Interface. It is the screen or panel where operators interact with machines.

beginner

Why is simplicity important in HMI screen design?

Simplicity helps operators quickly understand the machine status and controls, reducing errors and improving safety.

beginner

Name two common elements found on an HMI screen.

Common elements include buttons for control, indicators for status, and alarms for warnings.

beginner

What role does color play in HMI screen design?

Colors help highlight important information, like red for alarms and green for normal operation, making it easier to spot issues.

beginner

How can navigation be improved on an HMI screen?

By using clear menus, consistent layout, and easy-to-find buttons, operators can move through screens quickly and without confusion.

What is the main purpose of an HMI screen?

A To store machine data permanently

B To allow operators to control and monitor machines

C To program the PLC logic

D To replace the machine hardware

The HMI screen is designed for operators to interact with machines by controlling and monitoring them.

Which color is commonly used to indicate an alarm on an HMI screen?

A Red

B Blue

C Green

D Yellow

Red is typically used to show alarms or urgent warnings on HMI screens.

What is a good practice for text size on HMI screens?

A Large enough to read easily from a distance

B Use fancy fonts for style

C Only use uppercase letters

D Very small to fit more info

Text should be large enough for operators to read easily, improving usability and safety.

Which element is NOT typically found on an HMI screen?

A Alarm messages

B Status indicators

C Control buttons

D Machine wiring diagrams

Machine wiring diagrams are usually not shown on HMI screens; they are found in technical manuals.

Why should navigation be consistent across HMI screens?

A To confuse the operator

B To make the screen look colorful

C To help operators find controls quickly

D To increase programming complexity

Consistent navigation helps operators quickly find what they need, reducing errors and saving time.

Explain the key principles to follow when designing an HMI screen for industrial machines.

Think about what helps an operator work safely and efficiently.

Describe how color coding improves the usability of an HMI screen.

Consider how colors catch attention and convey meaning.

Practice

1. What is the main purpose of an HMI screen in PLC programming?

easy

A. To store machine data permanently

B. To write complex PLC code

C. To replace the PLC hardware

D. To allow users to control and monitor machines easily

Solution

1. Step 1: Understand HMI function

   An HMI (Human-Machine Interface) screen is designed to help users interact with machines.

2. Step 2: Identify main purpose

   The main goal is to make control and monitoring simple and clear for users.

3. Final Answer:

   To allow users to control and monitor machines easily -> Option D

4. Quick Check:

   HMI = control and monitor [OK]

Hint: HMI means user interface for machine control [OK]

Common Mistakes:

• Confusing HMI with PLC programming itself
• Thinking HMI stores data permanently
• Assuming HMI replaces hardware

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

easy

A. Use only icons without text

B. Use vague text like 'Click Here'

C. Use clear text like 'Start Motor'

D. Use very long sentences explaining the button

Solution

1. Step 1: Understand button labeling

   Buttons should have clear, simple labels so users know their function immediately.

2. Step 2: Evaluate options

   'Start Motor' clearly tells the user what the button does, unlike vague or overly long labels.

3. Final Answer:

   Use clear text like 'Start Motor' -> Option C

4. Quick Check:

   Clear labels = better usability [OK]

Hint: Label buttons with clear, simple text [OK]

Common Mistakes:

• Using unclear or vague labels
• Relying only on icons without text
• Writing long explanations on buttons

3. Consider this HMI screen design rule: "Use consistent colors for similar controls." What is the likely result if this rule is ignored?

medium

A. Users may get confused about control functions

B. The PLC program will stop working

C. The screen will load faster

D. The machine will run automatically

Solution

1. Step 1: Understand color consistency

   Consistent colors help users recognize similar controls easily.

2. Step 2: Predict effect of ignoring rule

   If colors vary randomly, users may not know which controls do similar things, causing confusion.

3. Final Answer:

   Users may get confused about control functions -> Option A

4. Quick Check:

   Consistent colors = less confusion [OK]

Hint: Consistent colors help users understand controls [OK]

Common Mistakes:

• Thinking color affects PLC operation
• Assuming color changes speed up screen
• Believing color affects machine automation

4. You designed an HMI screen but users report they can't find the navigation buttons easily. What is the most likely design mistake?

medium

A. Navigation buttons are hidden or placed inconsistently

B. Buttons have clear labels and consistent colors

C. Screen title is too large and clear

D. Screen uses standard navigation layout

Solution

1. Step 1: Analyze user feedback

   Users can't find navigation buttons easily means buttons are not visible or confusingly placed.

2. Step 2: Identify design mistake

   Hidden or inconsistent placement of navigation buttons causes difficulty in finding them.

3. Final Answer:

   Navigation buttons are hidden or placed inconsistently -> Option A

4. Quick Check:

   Visible, consistent navigation = easy to find [OK]

Hint: Place navigation buttons clearly and consistently [OK]

Common Mistakes:

• Ignoring button placement importance
• Assuming large titles improve navigation
• Using non-standard layouts without testing

5. You want to design an HMI screen for a machine with multiple steps. Which approach best helps users navigate smoothly between steps?

hard

A. Place all controls on one screen without navigation

B. Use a clear menu with buttons labeled for each step

C. Use random colors for each step's controls

D. Hide navigation buttons to save screen space

Solution

1. Step 1: Understand multi-step navigation needs

   Users need to move easily between steps without confusion.

2. Step 2: Evaluate navigation methods

   A clear menu with labeled buttons helps users know where to go next and jump between steps.

3. Step 3: Reject poor options

   Putting all controls on one screen can overwhelm users; random colors confuse; hiding buttons blocks navigation.

4. Final Answer:

   Use a clear menu with buttons labeled for each step -> Option B

5. Quick Check:

   Clear menus = smooth navigation [OK]

Hint: Label navigation buttons clearly for each step [OK]

Common Mistakes:

• Overloading one screen with all controls
• Using inconsistent colors that confuse users
• Hiding navigation buttons to save space