What are Human-Machine Interfaces (HMIs)?
Human-machine interfaces (HMIs), also known as user interfaces (UIs), operator interface terminals (OITs), or man-machine interfaces (MMIs), are hardware and software solutions for the exchange of information between systems/machines and a human operator. HMIs enable control, management, and visualization of device processes, ranging from simple inputs on a touch display to control panels for sophisticated automation systems. They populate multiple units such as portable handheld devices, machines, centralized control rooms, factory floor machines, and process control. Applications include industrial and building automation, digital signage, vending machines, medical, automotive, aviation, appliances, and much more.
HMIs provide the means to interact with modern technology, and include interfaces such as:
- Simple screen displays
- Advanced touchscreens
- Multi-touch enabled control panels
- Push buttons
- Mobile devices
Interface functionality varies from device to device or machine to machine, depending mainly on individual machine functions and the controls that are necessary to coordinate operation. Regardless of the type employed, the purpose of an HMI is to enable the performance of control functions, while at the same time ensuring an intuitive user experience.
HMIs in an Industrial Setting
HMIs make technology accessible, enabling the visual display of data in an equipped industrial setup, tracking production, and monitoring machine I/Os and operations. They offer a visual representation of a control system with real-time data acquisition. HMIs can be a standalone terminal or distributed for larger, more complex applications. In the industrial setting, they are frequently used in machine and process control, connecting machines, sensors, and actuators from the plant floor to systems such as I/O and PLC applications.
Figure 1: HMIs can be a standalone terminal or distributed for larger, more complex applications. Image Source: newhavendisplay
Let's Dig a Little Deeper: The Benefits of Industrial HMIs
Adding an HMI to a workplace benefits a facility by improving its productivity, operation, and safety. The following are a few of the many benefits of having an HMI system:
- Enhanced visibility: HMIs provide enhanced visibility for industrial operations at all times and allow users to visualize the performance of equipment or facilities from a single dashboard, even remotely. These capabilities improve productivity over time and enable a quick response to alerts.
- Increased efficiency: Because an HMI offers constant access to real-time data, users can monitor production and adjust to changing demand in real-time. Data visualization, especially when combined with data analysis technologies, can help identify areas where improvement is required.
- Decreased downtime: With alerts on a central dashboard, one can swiftly respond to problems, reducing downtime. Viewing and analyzing equipment performance data can also help identify potential mechanical issues before they escalate into situations that may cause significant downtime.
- Improved usability: HMIs provide visualizations, such as graphs and charts, making it easier for users to view and understand data.
- Cost Reduction: An HMI can reduce operating costs by replacing hundreds of selectors, pushbuttons, indicator lights, and more, significantly reducing the need for extra cables, panels, and consoles.
Current Trends in Industrial HMIs
The last few decades have ushered in a radical change in the ways people interact with industrial systems. The requirements that currently drive the trends of industrial HMI application design are:
- Larger and more complex networked systems
- Significant volumes of data
- Increased levels of automation
- The expanded use of remote operations
Touchscreens, mobile devices, cloud-based HMIs, and high-performance HMIs are now almost commonplace in an industrial setup. High-performance HMIs help ensure fast, effective interaction by drawing attention only to the most necessary or critical interface indicators, helping the viewer to see and respond to problems in a more efficient manner.
Remote Monitoring with the Help of HMIs
Remote monitoring is another feature that is essential to HMIs. Through network connectivity and the Internet, many modern systems do not require a user to be physically present for their administration. Remote monitoring gives users location-agnostic access to dashboards and reports, as well as control over various processes.
In addition, advanced technologies like the Internet of Things (IoT), cloud computing, and data analytics technologies are now a big influence on how HMIs operate. As more devices connect online, HMIs collect increased amounts of data and use advanced analytics techniques to help companies fully leverage the information their devices are gathering. The coming years will see leading engineers explore ways to implement AR and VR to visualize manufacturing functions.
The Advantage of Touchscreen HMIs
Touchscreens are a critical component for modern HMI systems, making an interface that controls multiple system functions from a single point much more intuitive. A touchscreen makes an HMI more user-friendly and informative by presenting data, in addition to facilitating control. Touchscreens can also be updated via software, without requiring new hardware. Additionally, multi-touch technologies are emerging to expand the range of functionality for increased productivity. Many industrial applications favor using touch-based technology as operator panels, control and monitoring devices, and industrial PCs.
Industrial touch screen HMIs provide direct interfacing with machines, leaving behind hardware peripherals such as a mouse and keyboard. These kinds of HMIs make it possible to complete tasks faster, iterate in real-time, and share data easily between stages of the construction process. Reprogramming ease, wiring reductions, and increased flexibility are additional advantages of touch-based HMIs.
Security is also improved. Touch-based HMIs can be password protected, while hardware controls such as joysticks, faders, and knobs cannot. One important feature of industrial touch screen displays is that they are constructed entirely of industrial-grade materials, which usually last much longer and are far more rugged than consumer-grade devices like smartphones and tablets. They should resist dust, moisture, extreme temperatures, water, and, in some instances, exposure to hazardous chemicals; all of these are factors that can lead to false triggering and, consequently, safety and productivity issues.
Focus on Bridgetek Industrial HMI Chips and Boards
The BT817 advanced Embedded Video Engines (EVEs) from Bridgetek are graphic controllers designed for developing HMIs with embedded applications. EVE technology utilizes an object-oriented methodology to make development straightforward and simple. With support for display, audio, and touch, EVE allows engineers to quickly and efficiently design HMIs and deliver robust solutions using hi-resolution displays at lower costs.
Bridgetek BT817 graphic controller ICs are used in several industries and applications, including retail, digital signage, office management systems, public information units, vending machines, domestic appliances, training/educational equipment, and interactive maps and exhibits.
|Figure 2a: Bridgetek BT817 graphic controller IC||Figure 2b: Block Diagram of a BT817 graphic controller IC|
BT817 Advanced Embedded Video Engine
Image Source: Bridgetek Datasheet
The block diagram above shows how easily the interface can process images, sound, and information from the touch panel. The external microcontroller and flash memory are both connected to the EVE IC by using quad SPI. Color palettes, object creation, and anti-aliasing are supported natively.
The EVE IC is suitable for use with 1 Mpixel displays and supports LCD resolutions of 1920×480, 1440×540, 1280×800, 1024×600, 800×600, 800×480, 480×272, and others. It supports capacitive touch screens with up to 5 touchpoint detection. The BT817 EVE operates at I/O voltage ranging from 1.8V to 3.3V, with an internal voltage regulator that supplies 1.2V to the digital core. They are available in a compact Pb-free VQFN-64 package and have an extended operating temperature range of -40°C to +85°C.
Prototyping New HMIs with the ME817EV Evaluation Board
To facilitate the development and prototyping of HMIs based on object-oriented graphic controller ICs, Bridgetek has introduced the ME817EV evaluation board (Figure 3), featuring the BT817 EVE. The ME817EV is used primarily to develop and demonstrate the BT817's graphics, touch, and audio functionalities.
The board can interface with large-scale, high-resolution display modules, such as 1280×800 pixel displays through a 40-pin LVDS interface and 50-pin RGB interface for 1024×600 pixel displays. Capacitive touch screens can be connected to the board through a 10-pin or 6-pin FPC connector. An audio filter and amplifier are included on-board, providing 1/8 watts of power.
The ME817EV board supports two host controllers: an MCU with SPI/QSPI master or a USB host, each selectable through dip switches. The board can be powered via a 5V DC power supply using the SPI host connector or via the USB Type-C port.
Image Source: Bridgetek
Let's Recap: HMIs Provide a New Level of Control
Human-machine interfaces are in a constant state of evolution, with current iterations having advanced far beyond basic local visualization. Integrating high-performance HMIs, remote monitoring, IoT, data analytics, and cloud-based systems with machine interfaces has added a new level of control to industrial applications. Touch screens have become the mainstream HMIs in industrial applications, offering advantages such as increased flexibility, wire reduction, user-friendliness, and reprogramming ease.