Keeping people in mind – for a safe, reliable and ergonomic HMI design
09 October 2017
Human Machine Interfaces (HMI) encompass all the elements a person will use to interact with a machine.
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The task of the HMI expert is to build innovative, intuitive and reliable interfaces. HMIs play a vital role in machinery design and industrial automation, enabling the efficient operation and monitoring of essential processes. This article provides a viewpoint of those important tactile, electromechanical controls which remain essential for safe, reliable, ergonomic HMI design.
According to a report from the European Agency for Safety and Health at Work, the high proportion of employees working with machines or computers indicates an essential need for proper HMI design. Poor design can lead to a rise in occupational diseases, such as stress or musculoskeletal disorders, as well as an increase in the risk of occupational accidents. The potential cost to an employer due to reduced productivity, damaged reputation, or users’ dissatisfaction is evident. Proper HMI design in equipment and the workplace is of utmost importance.
To meet increasing demands, it’s been essential to develop specially engineered HMI Components and HMI Systems that will ensure ‘safe’ operation even under the most adverse of conditions. When it comes to keeping people safe, there can be no compromises.
Human Machine Interface’s vital role in machinery design
HMIs enable the efficient operation and monitoring of essential processes. Innovations within SCADA (Supervisory Control and Data Acquisition) systems are pushing industrial companies to generally improve the quality of the interfaces to reflect modern styles. Screen-based master controllers have enhanced capabilities to visualise and display production processes, typically in combination with a tactile control panel for primary system start-up, safety and security functions. Despite this migration of features to screens and visualisation software, illuminated switches such as pushbuttons, indicators, selectors, toggle switches, etc., remain essential in what can be referred to as a “mixed technologies” solution. As well, modularly assembled products can be easily configured to meet most of the demanding requirements of many applications.
Advanced HMI components for demanding machinery
HMI Component technology has adapted to serve the increasingly specialise needs of machinery. Designers today face an eclectic range of choices in electromechanical components that encompass not only the type of device, electrical specifications, environmental sealing, mounting and termination styles, but also ergonomic considerations such as appearance, configuration, size, illumination and tactile feel.
Today’s advanced HMI Components are precisely crafted devices, made to exacting design specifications and precise tolerances from high-grade plastics, metals, and carefully calibrated springs. To achieve reliable, long service lives, they are engineered like fine watches with the performance, feel, and look required in modern HMI Systems.
Food and beverage manufacturing
Machine and process controls in the food and beverage industry not only have to work efficiently and safely, but are also frequently subjected to the influences of moisture, dust and cleaning fluids. Considering the great variety of operating requirements, it is therefore extremely important to make the interaction between the operator and the machine safe, intuitive, reliable and repeatable.
Taking into account the long service life, it’s essential to develop reliable, high-quality operating concepts for machines in accordance with IP, NEMA, IEC, ADA, ANSI and OSHA.
Semiconductor and electronics production
It is necessary to have a thorough knowledge of the special requirements in the manufacturing of semiconductors and electronic devices, plus a complete understanding of the functional and regulatory requirements.
Applications in semiconductor and electronics production require many operator control terminals. These often consist of industrial PCs with touchscreen displays interfaced to production machines, plus a number of discrete electromechanical components. Emergency-stops, for example, are considered to be a discrete function in this market. The system design needs to be made in accordance with the SEMI S2 guidelines.
Intuitive operation, interactivity and full functionality are also vital factors. It’s critical the design meets industry-specific requirements such as clean-room regulations and precision control with flexible, high-quality components.
Packaging systems, especially those in food and beverage industries, operate in a clean production environment geared towards high work volumes. HMI Systems must comprehensively protect against the ingress of fluids or solids that are found in packaging factories, while still making it easy and safe for users to perform their tasks. Control systems must be quickly and easily set-up and adjustable to new production processes.
The goal is to make this essential process easier, faster, and more accurate. To be successful, a HMI manufacturer needs knowledge in machine integration and functioning logic, project management, appropriate documentation for line qualification, and testing of centralised advisory services.
CNC milling and machine tools
The ability to quickly visualise and control every aspect of the production environment is critical within both simple and complex machine tools operations such as CNC milling, lathing, and boring equipment. Operator controls must be designed and arranged for maximum user-friendliness to ensure error-free switching between the various production steps.
HMI systems design process
Defining the requirements is the most critical and important step for developing an HMI System. The basic concept is to be mindful that the HMI is the user-link, and brand recognition, to all system functions. Failure to consider this can affect the acceptance and usability of the entire machine and damage the equipment manufacturer’s name within the industry.
Industrial design and ergonomics
Industrial design refers to the features of shape, configuration, pattern, and ergonomics for a device designed for the machinery sector. A definition for much of the design will come from its application including the user environment, operating temperature range, presence of moisture, and ambient light requirements.
A design should strive for an intuitive presentation of user tasks. An intuitive layout with the use of dimensional shapes and well thought out groups of operations provides a consistent and efficient HMI System.
Component manufacturing expertise
When manufacturing HMI Systems for an entire spectrum of market requirements, quality is critical. A high-grade product range featuring a variety of flexible components will help generate effective HMI Systems.
The ‘mixed technology’ approach to component selection
HMI System design and manufacturing should focus on providing the necessary components to effectively meet customer application requirements. A complete review of the application, functional requirements and needs of the operator should be completed. This knowledge is then used to select the appropriate control technology.
A “mixed technologies” approach can differentiate function, increase usability, and control production costs. No single technology satisfies every operator and end user need. The flexible approach to using multiple technologies offers customers a real competitive edge.
Software and interface design
Modern HMI solutions feature fieldbus connections for communicating with complex systems. Software adaptations make it possible to configure and control HMI subsystems. Serial communication integration can connect buttons, indicators and other components as part of a complete HMI solution allowing the controls to be configured for plug-and-play connectivity.
Standards are of the highest level of concern within design considerations. The criteria specified within these general and industry specific requirements dictate features, functional attributes, and design elements. It is usually mandatory to abide by these conditions in order to be approved for participation within the identified market segment as they promote increased accuracy, performance and safety.
Standards for Human Factors designed within the machinery market include:
• Ergonomics, design, and materials standards
• Market and application specific: SEMI S2-93/12.4c
• IEC 60947-5-1/5, ISO 13850
• Safety agencies: UL, cUL, CE, VDE
Although it is understood that standards benefit the end user, they can sometimes create difficulty for design engineers involved within the creative process. Sufficient knowledge of industry standards is required to ensure design, production and delivery timelines are not affected.
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