Understanding and Applying Hmi Design for Effective Automation Monitoring

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Human-Machine Interface (HMI) design plays a crucial role in industrial automation, acting as the bridge between machine operators and industrial systems, allowing them to monitor processes, control equipment, and troubleshoot issues efficiently. Effective HMI design represents the critical difference between efficient, safe plant operations and costly mistakes that lead to production losses, safety incidents, and operator frustration. Human machine interface design quality directly impacts plant safety, operational efficiency, and profitability across all industrial sectors.

An intuitive and well-designed HMI improves productivity, reduces human error, and enhances workplace safety. Well-designed HMI systems reduce cognitive load on operators by presenting information in logical hierarchies that match mental models of process flow and equipment relationships, with research demonstrating that operators using properly designed interfaces make decisions 40-60% faster during abnormal situations.

What is Human-Machine Interface Design?

Human-machine interface (HMI) design creates systems and screens for users to interact with machines, development software, or devices, where a person uses a visual or digital interface to give a command or receive feedback from a machine. A Human-Machine Interface (HMI) is a digital or physical interface that enables operators to interact with machinery, control processes, and visualize data.

Every human-machine interface is ultimately designed to help people see what’s happening, take action when needed, and stay in control. The value of a Human-Machine Interface (HMI) is derived from how well it helps the plant-floor operator to oversee the manufacturing process, as no matter how automated a manufacturing process may be, there is still a need for an operator to monitor it, control it, and, at times, intervene to resolve problems.

The Evolution of HMI Technology

The early days of control interfaces consisted of banks of physical switches, analog meters, and paper chart recorders, followed by the first HMI which were cathode-ray tube (CRT) screens that displayed simple graphics, then liquid crystal displays (LCDs) which introduced color to the interface. The introduction of touch-sensitive displays marked a major breakthrough in technology, facilitating the development of user-friendly interfaces that presented real-time data and provided a means of control that was intuitive and visually appealing.

As HMIs have evolved, their capabilities expanded significantly, now offering a range of features to enhance functionality, such as data logging, alarm management, remote access, and diagnostics. With the advent of cloud computing and the Internet of Things (IoT), HMIs have become even more powerful, enabling real-time monitoring and control from anywhere in the world.

Twenty years ago, industrial workers used simple HMIs with one piece of software until the product expired, but today, smartphones are setting new standards for user experience, and the digitally native workers expect sophisticated interfaces that mirror smartphone functionality as a bare minimum—even in factory environments.

The ISA-101 Standard Framework

ISA-101 (Human Machine Interfaces for Process Automation Systems) is an international standard published by the International Society of Automation (ISA) that defines best practices for HMI design in industrial automation, covering display hierarchy, color usage, alarm integration, user interaction, and lifecycle management. The ISA-101 series of standards and technical reports provide a trusted roadmap for designing, implementing, operating and maintaining Human Machine Interfaces (HMIs) in modern process automation systems, focusing on improving safety, quality, productivity, and reliability.

These principles derive from human factors engineering research and decades of industrial automation experience across diverse process and manufacturing environments. All recommendations follow ISA-101 standards and proven industry best practices.

The HMI Lifecycle Approach

Creating and maintaining an effective HMI strategy is a multi-step process that can span decades from initial concepts to decommissioning, with ISA-101 taking a lifecycle approach to effective HMI management and seeking to identify, define and address different needs across this time span. As a true lifecycle-based standard, ISA-101 defines how to best use technologies through all phases of the HMI lifecycle, from design through implementation, operations, and maintenance, similar to the ISA 18.2/IEC 62682 standard for alarm management and the ISA 84/IEC 61508 and 61511 standards for process safety.

The main HMI lifecycle stages are Design, Implement and Operate, with HMI Philosophy, Style Guide and Toolkits providing a set of consistent documentation for HMI management at the site or companywide, while continuous work processes—including MOC, Audit and Validation—can occur throughout the lifecycle.

HMI Philosophy Document

The HMI Philosophy Document explains the principles and goals of HMI management at the site or larger company, and is automation platform independent, explaining how the ISA-101 lifecycle will be implemented, and the roles and responsibilities for individuals involved. The HMI philosophy provides independent or platform-specific guiding principles for HMI design at your plant.

HMI Style Guide

The HMI Style Guide explains specific aspects of implementing the HMI Philosophy within a specific automation system platform environment, with understanding the mechanics of the automation system platform being used making sure the implementation is easily maintainable, and ensuring the platform’s standard built-in capabilities are used as much as possible. When implementing these principles on a real project, prioritize standardizing screen templates before building individual screens, defining header layout, color palette, font sizes, button styles, and alarm banner placement once.

Core Principles of Effective HMI Design

Core HMI design principles establish the foundation for creating effective operator interfaces regardless of specific industry, platform, or application. Key focus areas include human-centered design, effective display structures, intuitive user interaction and the importance of operator training.

Visual Hierarchy and Information Architecture

Visual hierarchy guides operator attention to the most important information while maintaining awareness of overall system status, with proper hierarchy implementation using size, color, contrast, position, and animation to create clear distinction between critical alarms, important process variables, and background information that operators need for context but not immediate action.

Information architecture organizes HMI content in logical structures that match operator mental models of process equipment and control strategies, with effective organization following process flow, equipment grouping, or functional areas rather than arbitrary arrangements.

Simplification Without Information Loss

Simplification doesn’t mean removing important information—it means organizing and presenting information efficiently without clutter or confusion, with well-designed HMI screens conveying complex process relationships clearly through thoughtful layout, appropriate abstraction, and logical grouping rather than showing every possible data point simultaneously.

A well-designed HMI with the right interface components should display only essential information in a clean, structured layout, enhancing efficiency and usability by showing only essential data to avoid screen clutter.

Unambiguous Indication and Clear Labeling

Unambiguous indication ensures operators can determine equipment status, alarm conditions, and process variables at a glance without interpreting ambiguous symbols or reading detailed text, with clear visual differentiation between running and stopped equipment, normal and abnormal conditions, and automatic versus manual control modes preventing misinterpretation.

Meaningful labeling uses descriptive names that operators understand rather than cryptic abbreviations, PLC tag names, or engineering terminology. Labels should match the users’ understanding of the machine or operations (their mental model), as users may not refer to the tank by its technical label even though that is the technical designation, instead referring to it by a more familiar name.

Display Hierarchy and Navigation Structure

ISA-101 provides a framework and guidelines for the design and implementation of HMIs in process industries, emphasizing creating interfaces that improve the safety, efficiency, and reliability of operational responses. One of the most important aspects of ISA-101 is its hierarchical approach to display organization.

The Four-Level Display Hierarchy

HMI display designs should be based on task analysis and ergonomics, not on P&IDs, with displays needing to provide for execution of detailed tasks as well as an overview of the operator’s realm of control, and a display navigational hierarchy developed allowing the operator to drill down to greater levels of detail, with ISA-101 recommending no more than four levels of hierarchy.

Level 1 – Overview Display: The overview screen shows the entire process at a high level with key performance indicators and status for each major section, serving as the home screen and the screen that should appear after any period of inactivity. Level 1 or Level 2 displays should be based on operator realm of control and KPIs (key performance indicators), not based on P&IDs, and should provide a concise but informative status of the process.

Level 2 – Area Screens: Area screens show one screen per major process section showing equipment detail, operating parameters, and local controls.

Level 3 – Task Detail Displays: Operators can control individual components such as pumps, valves, or boilers from this level, equipped with the necessary real-time data, controls, and detailed operational statuses, designed for active engagement with the process, where most routine operations are executed.

Level 4 – Configuration and Diagnostics: Level 4 screens are used for settings, maintenance activities, system diagnostics, and configuration tasks and is often associated with faceplate controls for devices, sequences, unit parameters, etc., with these interfaces less frequently accessed and typically restricted to specialized personnel, including detailed settings that can adjust the parameters of the process or equipment, and providing comprehensive diagnostic data useful for troubleshooting and maintenance.

Operators should be able to reach any screen from any other screen within two touches or clicks. Avoid deep navigation trees. Each level is designed to provide information that is contextually relevant to specific operational needs and user roles, ensuring that operators are not overwhelmed by unnecessary data but also enabling them to quickly and accurately assess operational situations and make informed decisions.

Color Theory and Visual Design Standards

One of the most misunderstood aspects of ISA-101 is its approach to color usage. Many believe ISA-101 merely advocates for the use of dull, grayscale graphics on Human Machine Interfaces (HMIs), which some operators find visually unappealing and uninspiring, however, this perception misses the broader and much more crucial intent of the standard: enhancing usability and promoting effective decision-making through well-organized HMI designs.

The Purpose of Gray Backgrounds

Effective HMI follows the ISA-101 high-performance principles: gray backgrounds instead of colorful graphics, information hierarchy from overview to detail, limited use of color. The gray background approach serves a specific purpose: it allows color to be reserved for indicating abnormal conditions and critical information, making these elements immediately visible to operators.

Use color, position, isolation, and size to emphasize important information. When color is used sparingly against a neutral background, it becomes a powerful tool for drawing attention to what matters most.

Designing for Color Impairment

Modern HMI design must account for operators with various types of color vision deficiencies. Best practices include using redundant coding methods that don’t rely solely on color to convey critical information. This might include combining color with shape, position, brightness, or text labels to ensure all operators can accurately interpret system status regardless of their color perception abilities.

Alarm Management and Notification Systems

Operators need clear, well-organized alarm systems to respond quickly to potential issues. Effective alarm management is one of the most critical aspects of HMI design, directly impacting operator response times and safety outcomes.

Alarm Prioritization and Presentation

Alarm systems should clearly distinguish between different priority levels, ensuring that critical alarms immediately capture operator attention while lower-priority notifications don’t create unnecessary distraction. Make alarms and notifications intuitive, reducing cognitive load.

Alarm shelving and suppression capabilities should be built into the HMI, but with appropriate security levels and automatic unshelving timers, with no alarm being permanently silenced without a management-of-change review.

Alarm Flooding Prevention

One of the most dangerous situations in industrial automation occurs when operators face alarm flooding—dozens or hundreds of alarms activating simultaneously during an abnormal situation. Effective HMI design prevents alarm flooding through intelligent alarm rationalization, grouping related alarms, and implementing proper alarm suppression logic that prevents cascading alarms from overwhelming operators when they need clarity most.

Data Visualization and Analog Displays

The most important goals to focus on for optimizing the HMI are to turn data into useful information and to draw attention to the information that is most important for the operator to see.

Advantages of Analog Displays

Analog displays are more effective than digital displays at putting data into a practical context, similar to how an analog watch is better than a digital watch at showing how much time you have until your next meeting when you’re in a hurry, as the digital watch simply has numbers that show you what time it is while an analog watch displays the current time and makes it easy to see how much time is left.

From that small example, you can imagine how much easier analog displays make it to assess dozens of process values on a screen, with the operator instantly able to see where the current conditions stand in comparison to desired conditions.

Use embedded trends that show where data is heading. Allow trends and historical data to be easily reused and integrated. Trend displays help operators understand not just current conditions but the direction and rate of change, enabling proactive intervention before conditions reach critical thresholds.

Situational Awareness and Operator Effectiveness

A well-designed HMI facilitates effective human oversight, enhances situational awareness, and mitigates risks associated with system failures or unexpected scenarios. The layered approach outlined by ISA-101 is critical for maintaining situational awareness.

Supporting Decision-Making Under Pressure

By conveying important information effectively, a high-performance HMI can aid operators in quickly assessing what needs to be done. HMIs, with their ability to present vast amounts of information in an easily-digestible manner, contributed to significant gains in efficiency, with real-time data on process variables, equipment status, and production metrics empowering operators to make informed decisions quickly.

A well-designed HMI is the difference between an operator who catches a developing problem in seconds and one who stares at a screen full of flashing colors while production grinds to a halt, with poorly designed screens leading to slower response times, higher error rates, and frustrated operators who resort to workarounds that undermine the system.

Reducing Cognitive Load

Cognitive load refers to the mental effort required to process information and make decisions. Effective HMI design minimizes unnecessary cognitive load by presenting information in intuitive formats, using consistent conventions, and eliminating visual clutter. This allows operators to focus their mental resources on understanding process conditions and making appropriate control decisions rather than struggling to interpret the interface itself.

Typography and Text Presentation

Text on HMI displays should be clear and easy to read as it is important to the users’ understanding of navigation, using Sans Serif font to improve readability and a consistent font size for data, captions, title, and headers (typically 10pt font).

Primary data should be larger and use a bold typeface, using a larger font size than their corresponding labels and units to make data stand out. Font sizes are dependent upon screen size and how the users view the monitor, with a large monitor mounted high on a wall or ceiling that is meant to show data at a distance from users potentially needing a larger font than a monitor viewed up close.

Numeric data that is related and meant to be compared should be like-justified with the decimal points aligning. This alignment makes it easier for operators to quickly scan and compare values.

Responsiveness and Real-Time Performance

An HMI that lags behind the process is worse than no HMI at all, with screen refresh rates needing to be fast enough that operators perceive the display as real-time, with a one-second update rate adequate for most process applications, though high-speed discrete applications like automated assembly systems may require sub-second updates on critical indicators.

Test your HMI performance under realistic conditions: full alarm loads, multiple screens open, historian logging active, and the network carrying normal traffic, as performance problems that appear only under load are the most damaging because they occur precisely when the operator needs the system most.

User-Centered Design and Customization

Not all machine operators have the same level of technical expertise, with customizing HMIs for different user levels improving usability and efficiency. Modern HMI systems should support role-based access and customization, allowing different user groups to access the information and controls relevant to their responsibilities.

Involving End Users in Design

Implementing good HMI design involves collaboration between engineers, designers, and end-users. Automation suppliers and system integrators advising users while developing this document can draw on experiences of working through HMI implementations across many industries. Conducting user testing helps identify usability issues before deployment, and gathering operator feedback during operation enables continuous improvement.

HMI systems should evolve based on real-world operator feedback to maximize usability. An HMI should never be considered static, with systems needed for periodic monitoring, for gathering and evaluating user feedback, and for making revisions to optimize HMI displays over time, with the procedure including detailed change logs.

Modern HMI Technologies and Platforms

The industrial automation market offers numerous HMI platforms, each with specific strengths and capabilities. Understanding platform-specific features helps designers leverage built-in functionality rather than creating custom solutions.

Ignition (Perspective) uses built-in responsive design for mobile-friendly HMIs and leverages the component library for consistent look and feel. FactoryTalk View uses global objects for reusable components and implements navigation via display macros. AVEVA InTouch uses ArchestrA graphics for scalable, reusable display elements.

Mobile and Responsive Design

Modern industrial environments demand HMI designs that support both experienced operators and new personnel, function reliably across different screen sizes and resolutions, integrate seamlessly with mobile devices, and provide the situational awareness necessary for effective process control in increasingly complex automation systems.

Scrollable dashboards and responsive, adaptive layouts are becoming standard, with some systems even automating placement of elements so users don’t have to worry about design decisions, ensuring dashboards remain readable and functional across any device.

Scalability and Long-Term Maintainability

Your HMI architecture needs to stay reliable as technology evolves and user demands change, with short-term efficiency mattering, but true success meaning designing for long-term adaptability.

Component-Based Architecture

Developers and designers can work better together to optimize HMI performance—both in the short term and long run—by componentizing your architecture and not creating a monolithic solution. Build modular, reusable components to make dashboard creation simple and consistent, organize content with sections for clarity and focus, and enable flexible yet guided data visualization, including custom widgets.

Whether it’s a control panel for operating heavy machinery or a handset monitoring the security of a power plant, HMI designers should aim for a consistent and scalable architecture, with a consistent architecture coming from using well-established technology for all your HMI components and modules and aligning your HMI software design, architecture, documentation, and source code.

Benefits of Standardization

Consistency and scalability are crucial to ensuring long-term software reliability and advanced functionality, as they enable you to adapt to the latest trends from embedding new AI models to adapting to new hardware, work with multiple partners using well-established technology, lower maintenance costs by aligning all the key parts of software production, and help new developers and customers reuse previous software components and modules.

Security and Access Control

Security is critical in industrial automation, preventing unauthorized changes to machine settings. Modern HMI systems must implement robust security measures including user authentication, role-based access control, audit logging, and protection against cyber threats.

A well-designed HMI serves as a crucial safeguard against cyber threats, preventing unauthorized access and ensuring the integrity of vehicular operations in increasingly connected environments. While this reference relates to automotive applications, the principle applies equally to industrial automation where connected systems face similar security challenges.

Communication Protocols and Integration

HMIs must support various communication protocols to ensure seamless integration with a wide range of industrial equipment, with some of the most common protocols including Ethernet/IP, PROFINET and MODBUS TCP/IP for Ethernet-based communication, and PROFIBUS.

The choice of protocol affects the HMI’s ability to communicate with PLCs, sensors, and other devices in the automation system. HMIs often need to interact with Supervisory Control and Data Acquisition (SCADA) systems for higher-level monitoring and control.

Testing, Validation, and Commissioning

As part of the ISA-101 lifecycle model, new and revised HMI displays should be tested prior to being put into operation, with a simulation system able to greatly improve testing and training activities.

Comprehensive testing should include functional testing to verify all controls and displays work as intended, performance testing under realistic load conditions, usability testing with actual operators, and validation that the HMI meets all specified requirements and standards.

Training and Operator Competency

Even the best-designed HMI requires proper operator training to achieve its full potential. Training programs should cover not just how to use the interface, but also the underlying process logic, alarm response procedures, and troubleshooting techniques.

ISA-101 implementation phase efforts include requirements for testing, documentation, and training. Effective training ensures operators understand the HMI’s capabilities and can use it effectively during both normal operations and abnormal situations.

Management of Change (MOC) Processes

Help end users establish a process for managing changes to strategy, displays, graphics, locations, etc., with the procedure including testing and training requirements. In the operations phase, ISA-101 covers management of change and requirements for HMI operations, maintenance, and decommissioning.

A robust MOC process ensures that HMI modifications are properly evaluated, tested, documented, and communicated before implementation. This prevents unintended consequences and maintains system integrity over time.

Industry-Specific Considerations

While ISA-101 provides general principles applicable across industries, specific sectors may have unique requirements. Process industries like chemical manufacturing, oil and gas, and pharmaceuticals often require extensive alarm management and batch control capabilities. Discrete manufacturing may prioritize high-speed data updates and machine status visualization. Water and wastewater treatment facilities need geographic overview displays showing distributed assets.

This comprehensive HMI design guide has been developed by industrial automation engineers with 20+ years of experience designing operator interfaces for chemical processing, manufacturing, water treatment, and power generation facilities.

Common HMI Design Mistakes to Avoid

When an HMI is not in an optimal state it can become more of an obstacle than a solution, with one of the most common HMI problems being that the screens get so cluttered with color and detail that it’s difficult for the operator to quickly assess the situation.

Other common mistakes include:

  • Using PLC tag names instead of operator-friendly labels
  • Organizing displays based on equipment location rather than operational tasks
  • Implementing inconsistent navigation patterns across different screens
  • Overusing animation and dynamic elements that distract rather than inform
  • Failing to test HMI performance under realistic load conditions
  • Neglecting to gather and incorporate operator feedback
  • Creating deep navigation hierarchies that require excessive clicks to reach critical information

Measuring HMI Effectiveness

Organizations should establish metrics to evaluate HMI effectiveness and identify improvement opportunities. Key performance indicators might include operator response time to alarms, frequency of operator errors, time required to complete common tasks, operator satisfaction scores, and incident rates related to HMI usability issues.

By adopting these standards, teams can reduce operator error and improve situational awareness. Quantifying these improvements helps justify investment in HMI upgrades and demonstrates the business value of following design standards.

The field of HMI design continues to evolve with emerging technologies and changing operator expectations. Artificial intelligence and machine learning are beginning to enable predictive analytics and intelligent alarm filtering. Augmented reality offers new possibilities for overlaying digital information on physical equipment. Voice control and gesture-based interfaces may supplement traditional input methods in appropriate applications.

By exploring usability challenges, technological advancements, and the integration of rapidly evolving technologies such as AI (Artificial Intelligence), AR (Augmented Reality), and gesture-based controls, this study highlights how effective HMIs minimize cognitive load while maintaining functionality.

SPS 2025 reinforced that great dashboard design is both universal and nuanced, with dashboards now a baseline expectation, but the real challenge being making them intuitive, cohesive, and genuinely helpful.

Practical Implementation Strategies

The ISA-101 standard provides a formal framework for HMI design, but you do not need to implement a full HMI philosophy document to make meaningful improvements, with practical guidelines drawn from decades of building and commissioning automation equipment across industries.

Starting with Existing Systems

Organizations with legacy HMI systems can implement improvements incrementally rather than requiring complete redesigns. Focus first on the most critical displays and highest-impact improvements. Standardize color usage, improve alarm presentation, and enhance navigation before tackling comprehensive redesigns.

Building New Systems

For new HMI projects, invest time upfront in developing comprehensive philosophy and style guide documents. Create reusable templates and component libraries. Involve operators early in the design process and conduct iterative testing throughout development.

This can assist you in the implementation of ISA 101.01 in your application by providing reusable guidelines that follow standards as a starting point for your own HMI Style Guide, which can be further simplified by leveraging reusable libraries as your HMI toolkit for implementation.

Cost Considerations and ROI

The investment in proper HMI design is modest compared to the cost of the automation system it controls, but the impact on daily operations is disproportionately large, with an operator who trusts the interface and can find information quickly being an operator who keeps production running.

Even today with the new tools and approaches offered for HMI, many end users will spend up to $10,000 or more to develop each page of HMI graphics for their process operations. However, this investment pays dividends through reduced downtime, faster problem resolution, fewer operator errors, and improved safety outcomes.

Resources for Further Learning

Professionals seeking to deepen their HMI design expertise have numerous resources available. The ISA-101 standard itself provides comprehensive guidance, while technical reports expand on specific topics. Industry conferences offer opportunities to see real-world implementations and learn from experienced practitioners.

Books such as “The High-Performance HMI Handbook” provide practical guidance based on field experience. Online communities and professional organizations facilitate knowledge sharing among HMI designers and automation professionals. Many automation vendors offer training programs specific to their platforms.

For more information on industrial automation standards and best practices, visit the International Society of Automation website. Additional resources on human factors engineering can be found through the Human Factors and Ergonomics Society.

Conclusion

Effective HMI design represents far more than creating attractive graphics or implementing the latest technology. It requires a systematic approach grounded in human factors engineering, industry standards, and practical operational experience. ISA-101 is more than just a guideline for using grayscale graphics—it is a comprehensive approach to HMI design that enhances operator effectiveness and safety, with understanding and implementing the level-based organization of HMIs as prescribed by ISA-101 enabling process industries to significantly improve their operational clarity and response effectiveness.

HMI design plays a critical role in determining an operator’s ability to manage an industrial facility’s systems effectively, particularly when detecting and resolving an abnormal situation, with adopting design standards, such as those developed by groups such as ANSI and ISA, allowing organizations to add valuable context to data in a way that’s consistent, clear and scalable.

By following established principles, involving end users throughout the design process, implementing proper lifecycle management, and committing to continuous improvement, organizations can create HMI systems that truly empower operators to monitor and control complex automation systems safely and efficiently. The investment in proper HMI design delivers measurable returns through improved safety, reduced errors, faster response times, and enhanced operational productivity.

As automation systems continue to grow in complexity and capability, the importance of effective human-machine interfaces will only increase. Organizations that prioritize HMI design excellence position themselves for operational success in an increasingly competitive and demanding industrial landscape.