Basics of Good Design with HMI Software

Ineffective HMI design can negatively impact machine operators’ well-being and increase the risk of accidents. Complex, unclear, or cluttered HMI screens might confuse operators, while overly simple interfaces could lessen their engagement with optimizing or monitoring automated processes.

Although advanced systems often provide higher-level access to managers and other organizational roles, the most effective HMI interfaces are those tailored to the machine operators. These include essential visuals such as diagrams, digital photos, and detailed schematics when necessary. They also fully utilize the control system’s capabilities to meet high-performance standards without exceeding the budget allocated for HMI procurement.

Personalizing Software for Better HMI Design

Well-designed HMIs perform crucial functions, offering screens tailored for specific interactions between personnel and machinery. A consistent look and feel, matching the machine builder’s final product, enhances user comfort and minimizes distractions. This approach is not just about aesthetics; it’s about functionality and safety.

HMI Design and Safety Standards

Operators often work in challenging conditions, including noisy, dusty, or extreme temperature environments. Their well-being is paramount. Thus, HMI design plays a critical role in safeguarding their health, especially in sectors like manufacturing and construction.

Safety agencies, like the U.S. Department of Labor’s Occupational Safety and Health Administration (OSHA) and the European Agency for Safety and Health at Work, set guidelines for the physical installation of HMIs. These ensure safe use by workers.

Moreover, the evolution of graphical user interfaces in HMI displays, driven by studies on psychological ergonomics, has led to the establishment of best practices that significantly impact operator safety and health.

Maple Systems offers Class I Div 2 certified HMIs designed to keep operators and their environment safe.

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Best Practices in HMI Design for Superior Usability

Avoiding brute-force design approaches is crucial. Brute-force design in the context of HMI refers to the unrefined or direct replication of technical schematics, operational logic, or data presentation without considering user experience or interface usability. This approach often neglects the ergonomic and cognitive aspects of interface design, leading to interfaces that are complex, confusing, or overwhelming for users.

Effective HMI design requires a thoughtful analysis of how information and controls are organized, ensuring they align with users’ needs and cognitive processes, rather than merely displaying data or functions as they exist in the system’s backend.

An example of brute-force design is using a machine’s control diagram as the basis for the HMI’s navigational structure, or cramming screens with an excessive amount of data and controls. Such practices can significantly hinder efficiency, as they ignore the human capacity to absorb and process information. 

To counter this, effective HMI design focuses on consolidating functions into intuitive screens that are tailored for specific actions or tasks. This approach ensures that users are presented with the right amount of information and control options at the right time, enhancing usability and operational efficiency.

Thus, by prioritizing clarity and ease of use, designers can create HMIs that not only improve task performance but also reduce the risk of errors, making operations safer and more productive.

Navigational Structure in HMI Design

Organizing the HMI’s navigation hierarchically can enhance user experience. A top-level home screen should give an overview of the machine’s status and highlight urgent issues, similar to how notification badges work on smartphones. This design allows operators to address alerts quickly and efficiently.

Subsequent levels (one level down from the top-level homescreen) in the hierarchy should focus on specific operations, stripping away unnecessary information to facilitate task execution. For example, a dedicated screen for machine startup procedures can guide operators through safety checks and necessary actions, minimizing the risk of errors.

At the deepest level, screens should provide analytical and assistance materials. These include topics such as control tuning, analysis of throughput trends, and reviews of alarms and events. This setup enables experienced users to adjust advanced control features, including tweaking servomotor parameters and executing comprehensive commands across multiple axes.

Enhancing User-Friendly HMI Design

Designing and making Human-Machine Interfaces user-friendly is essential in industrial operations and automation to boost efficiency, enhance safety, and ensure the highest level of performance. However, creating these interfaces correctly can be challenging. 

Engineers often encounter difficulties due to a potential lack of understanding of the daily needs of the workers who use them. To address this, the following sections provide a detailed overview of potential HMI design issues and suggest possible solutions.

1. Engage with Plant Personnel for HMI Design Feedback

Engineers not fully versed in the processes monitored and controlled by HMIs often create systems that are complex and hard to use. These systems may require extensive training and deliver data in ways that overwhelm operators. However, better HMI designs emerge from closely working with those who know these processes best: machine operators and plant personnel.

That is why engaging with plant workers during the HMI design phase is vital. Their firsthand experience with daily operations allows them to offer valuable insights, making the HMIs more intuitive and effective.

Not to mention, prototyping plays a key role in this process. By deploying prototype HMIs and gathering feedback, engineers can refine their designs based on real user experiences. This collaboration can lead to significant improvements in communication and functionality.

Important to remember that consultation may lead to innovation when it comes to enhancing HMI design. By consulting with workers, engineers can gain insights into:

• Sensory Stimulation: How workers first perceive information on the HMI screen.
• Mental Organization: How workers recognize HMI elements, drawing on their previous experiences.
• Interpretation and Evaluation: How workers assess the machine’s status as communicated by the HMI and decide on appropriate responses.
• Recall: The ease with which workers remember the HMI’s screen structure.

Incorporating feedback from those who interact with HMIs daily enhances the design process. It ensures the creation of user-friendly interfaces that require minimal instruction and training.

2. Simplify HMI Screens for Safety and Efficiency

Complex HMI screens can lead to accidents on the plant floor or with equipment located remotely. The root cause is often the screen’s overcomplicated design, which can confuse operators. The key to prevention is simplifying these screens, focusing on presenting only the essential elements needed for machine operation. 

A minimalist approach, avoiding overly detailed renderings of machine subsystems, can enhance both safety and efficiency, making it easier for operators to manage their tasks without unnecessary distractions.

3. Enhance Decision-Making with Graphical Data Presentation in HMIs

Forcing quick decisions based on raw spreadsheet data can be a nightmare. Effective HMI software transforms this cumbersome data into easy-to-understand graphs and charts on a virtual dashboard. This approach not only simplifies data analysis but also significantly improves decision-making speed and accuracy.

In addition, advanced HMIs take advantage of Industrial Internet of Things (IIoT) technologies, seamlessly integrating with sensors and smart meters. This integration allows them to graphically display real-time data from sensors and smart meters at key locations on the machine.

By presenting this information visually, HMIs offer a clear overview of current machine performance against predefined setpoints and recommended thresholds. Also, trend lines provide valuable insights for immediate and proactive operator decisions.

This graphical representation fosters situational awareness, enabling operators to quickly identify both normal and unusual machine behaviors. Such awareness is crucial for maintaining optimal machine operation and preventing potential issues before they escalate.

4. Introduce Specialized Maintenance Screens for Enhanced Safety and Efficiency

Poorly designed HMI screens can complicate daily tasks and present major challenges for maintenance during troubleshooting and repairs. The solution lies in offering maintenance staff dedicated screens that are easily reached from the HMI’s main navigation screen.

These specialized maintenance screens should offer features that enable safe-mode operations, allowing for the secure handling of potentially hazardous machine parts. They should also facilitate the execution of specific tests, such as non-loaded performance drills, without risking equipment or personnel safety. 

Incorporating dedicated screens allows maintenance teams to work more efficiently and safely, minimizing downtime and boosting plant performance. This method enhances HMI system usability for maintenance, simplifying tasks for personnel and promoting effective, safe operations.

5. Maintain Consistency in HMI Symbology for Better Usability

Using a confusing mix of buttons, screen layouts, and icon styles can significantly distract workers. In contrast, HMI software that employs a clear, consistent design language, including standardized symbols, icons, and color schemes, greatly simplifies understanding and accelerates the initial setup process.

Leading HMI providers offer configuration tools that come equipped with templates and pre-defined symbol libraries. These templates guide the design aspects, such as font and color choices, while symbol libraries, often categorized by industry or specific applications, ensure visual consistency across the interface.

The strategic use of color is crucial in focusing workers and delivering key information, thanks to its unique ability to draw attention and convey meanings. While critical alerts should not depend solely on color, thoughtfully and consistently applying colors such as yellow and red can greatly improve the screen’s warning and alert systems’ impact.

By adhering to these principles, HMI software becomes more intuitive, helping workers to quickly interpret and react to information, ultimately improving efficiency and safety.

6. Implement Meaningful HMI Alarms to Enhance Operator Response

Alarms from HMIs that are irritating, unclear, overly loud, or excessively persistent can lead operators to dismiss or mute them entirely. Worse, it might lead to unauthorized and risky machine modifications to stop alarms from activating. Furthermore, HMI software that permits new alarm pop-ups to cover existing ones, particularly critical alerts, poses a risk by concealing important warnings.

Effective HMI design principles advocate for generating alarms only when immediate operator action is necessary. This approach helps operators focus on genuinely urgent issues without the need to mentally sort the urgency of each alarm. A practical method includes using a color-coded and numbered system to indicate alarm priority. This system guarantees that critical alarms remain prominently visible via a persistent badge on all screens. It also organizes other alarms in a hierarchy, prioritizing them according to the urgency of action needed.

Moreover, for situations that don’t demand immediate on-site intervention, modern HMIs with internet connectivity offer the option to notify maintenance or management staff via email. This ensures that the right personnel are informed promptly without overloading the operator with non-critical information.

This strategy boosts both safety and efficiency, further enhancing the HMI system’s functionality. It becomes a more dependable resource for operators and maintenance personnel alike.

7. Adapt to the Complexity of Systems with Thoughtful HMI Planning

HMIs are pivotal in merging complex systems, especially in sectors such as pharmaceuticals and medical device manufacturing. Here, they act as the core hubs for feedback and control within advanced Industrial Internet of Things (IIoT) frameworks. These systems enable ongoing, real-time optimization of operations, pushing the boundaries of what’s possible in modern manufacturing.

However, to fully leverage HMI connectivity, a carefully planned design strategy is necessary. This may introduce design engineers to new software challenges. Utilizing educational resources, HMI-specific configuration modules, and support from component suppliers becomes crucial. These strategies help overcome challenges, ensuring the successful integration and operation of advanced systems.