HMI Hardware
In the rapidly evolving world of industrial automation and control, the role of Human Machine Interface hardware stands paramount, bridging the gap between human operators and complex machinery. In this chapter, we will explore how HMI hardware combines ergonomics, connectivity, and industry standards to meet diverse application needs, from manufacturing to public service.
The best HMI hardware combines ergonomics and connectivity with satisfaction of all applicable industry standards. Reliable HMI hardware also includes robust HMI firmware to ensure end users can expect glitch-free operation of the HMI’s most advanced hardware capabilities.
The actual display portion of the HMI can be based on several different core technologies — and assume various physical configurations. After all, the HMI for an advanced CNC machine used to manufacture aerospace components must satisfy far different design requirements than an HMI serving as an outdoor public-transportation kiosk.
Key factors to consider for HMI hardware include:
- Environmental Conditions: Temperature, humidity, and dust exposure are crucial parameters. These affect the HMI’s durability and suitability for various environments.
- Vibrations: The HMI’s ability to withstand vibrations in its intended setting is vital, ensuring reliable operation under different conditions.
- User Interaction: It’s essential to assess the tasks users will perform through the HMI. The interface should offer maximum intuitiveness for all users, regardless of their familiarity with the system.
- Safety and Criticality: The risk level of processes controlled by the HMI determines the need for rigorous safety features.
Industry Standards for HMI System Compliance
HMI suppliers play a critical role in guiding Original Equipment Manufacturers (OEMs) through the maze of industry standards. These standards, set by organizations like the FCC, IEEE, UL, and ANSI, outline the necessary ruggedness, electrical safety, and cleanliness of HMI systems.
For example, the International Electrotechnical Commission (IEC) through its IEC 60529 standard, sets the ingress protection (IP) codes. These codes measure an HMI’s resistance to water and dust, ensuring devices remain operational in various conditions.
Similarly, the International Organization for Standardization (ISO) in its ISO 11064 standard, focuses on ergonomic design for control centers. This ensures the user’s comfort and efficiency, particularly in automated equipment settings.
The European Commission steps in with its EU Machinery Directives, ensuring electrically powered equipment, including HMIs, meet strict standards for electromagnetic interference (EMI). This certification is crucial for both industrial and consumer applications to prevent operational disruptions.
Marking on the back of an HMI
The Conformitè Europëenne (CE) Mark for industrial HMIs indicates that the component poses no electromagnetic interference (EMI) issues.
The ATmospheres EXplosibles (ATEX) standards, also from the European Commission, provide rules for ensuring safety in potentially explosive settings involving flammable chemicals such as petrochemicals as well as flour and sawdust.
Different standards apply to specific sectors, including transportation, semiconductor manufacturing, packaging, and healthcare. These guidelines ensure HMIs are tailored to meet the unique needs and safety requirements of each industry.
This guide also covers occupational safety standards in detail, particularly how they influence HMI software and graphical user interfaces (GUIs). Understanding these standards is essential for selecting the right HMI hardware, ensuring both operational efficiency and user safety.
Did You Know?
One option for OEMs looking to upgrade moderately sophisticated machines is to pre-integrate a mid-range HMI. The caveat here is that most HMIs directly mounted to machine frames must be ruggedized — with a plastic or even an aluminum enclosure to withstand exposure to water, vibration, and dust.
In the early stages of industrial automation, operator terminals such as the one pictured from a 1942 test facility were a far cry from today’s digital interfaces. They were wholly reliant on analog systems, where direct mechanical or electrical control was the norm. Consequently, operators would interact with machinery through an array of buttons, levers, and gauges, each manually calibrated to perform specific functions. Therefore, this method of operation required a deep understanding of the machinery, as feedback was provided through physical dials and meters, demanding constant vigilance and hands-on manipulation to maintain system performance.
IEC 60529 Ingress / International Protection (IP) Ratings
An Ingress Protection (IP) rating is a two-digit number set by the International Electro Technical Commission. It shows how well electronic devices or their enclosures are protected from things like dust and water. Specifically, the rating follows the EN60529 standard and uses the letters “IP” followed by two numbers that indicate the level of protection.
Example: IP65
- The first digit represents protection against ingress of solid objects.
- The second digit represents protection against ingress of liquids.
In short, the larger the value of each digit, the greater the protection.
Did You Know?
Maple Systems HMIs can connect to arrays of DIN-rail-mounted PLCs and I/O expansion modules to serve as integral parts of the machine controls.