Keeping the ‘human’ in human-machine-interface

Advances in human-machine interfaces (HMIs) are more lean and efficient with wearable technology and web-based software.

By Eric Reiner October 10, 2017

The human-machine interface (HMI) starts with the word "human," but for most of the technology’s history, the HMI has been more in favor of the machine than the machine’s operator. Arguably, it has been the burden of humans to adjust to the ways machines provide information and not the other way around. In recent years, HMI hardware has evolved to take on the user-friendly interface technologies popularized in consumer electronics. This has happened in ways that cater to preferences in build quality and screen layout. For many machine builders and end-users, low-end HMI devices made out of plastic and fitted with single-touch 6-inch screens just don’t cut it anymore.

Industrial HMI hardware options are available with precision-machined aluminum and steel housings that also offer high-definition widescreen or portrait orientation to expand upon traditional 4:3 and 5:4 orientations. More importantly, capacitive multi-touch technology has changed the way hardware and software vendors conceptualize the HMI, with increased emphasis on the "human" part of the equation. With these advances, industrial HMI vendors enable machine builders and manufacturers to implement intuitive visualizations that integrate the gestures popularized by mobile devices such as smartphones and tablets.

Instead of pushing many buttons to access various screens, now it is possible to swipe across HMI software to obtain the required information much faster than before. Mobile devices themselves now can be considered HMI hardware with the advent of HMI software platforms that integrate web developer standards, such as HTML5 and JavaScript. This means that an HMI can be any piece of glass with a web browser. 

The benefits of web-based HMIs

Beyond the "cool factor," web-based HMIs have benefits. Machine operators and technicians no longer have to stop what they’re doing and move back and forth to a stationary HMI display mounted in a specific area of a machine to check parameters or retrieve data during commissioning, troubleshooting, startup, or changeover. This dynamic easily can be reversed today, as the web-based HMI can "follow" the plant personnel, right to a smartphone or tablet. The same principle holds true for wearable HMI concepts, so that even smart watches and data glasses can bring augmented reality (AR) to the plant floor. Beyond the HMI screens themselves, communicator applications have been created that can enable push notifications. These applications can send messages relevant to machine operations to all mobile and wearable devices.

Despite the rapid growth of mobile technologies in HMI applications, advances in communication technology have not stopped the HMI devices from being installed on the machine. Using Internet of Things (IoT) communication standards such as OPC unified architecture (UA) and message queuing telemetry transport (MQTT), panel PCs (PC-based controllers with built-in display screens) can send continuous plant and manufacturing data up to cloud-based services for viewing across the enterprise and for implementing Big Data analytics. The data can be pushed securely, with data encryption to analytics dashboards and/or served up to web-based pages that can be viewed by authorized users anywhere, anytime. 

Power to the panel, operators

A trend that has been developing even longer than HMI taking on the functionality of mobile devices is the increasing performance of HMI hardware. Moving down from the cloud to machine to machine, these same panel PCs also can act as masters for industrial Ethernet communication, such as via EtherCAT. This further increases the multitasking capabilities of a panel PC. Control companies that promote PC-based control have offered all-in-one HMI and controls devices for decades when the HMI display has an integrated central processing unit (CPU) (as opposed to a passive panel). This means that, with the appropriate processor performance, the HMI hardware has the potential to run not just the HMI software, but also the software for programmable logic controllers (PLCs), motion controls, and other functions, which is easier than integrating HMI hardware, a separate PC, and a stand-alone hardware PLC.

Typical panel PC CPU types range from basic to running the gamut of major chipsets. With this level of computational horsepower, the HMI hardware can take on even more complex functionality on one device for CNC, robotics, condition monitoring, and more. In the process, engineers can cut the clutter of superfluous hardware to make leaner, smaller, and more efficient machines that do more with less.

HMIs can be so much more to a machine—and to operators—than that plastic panel with the 6-in. screen.

Eric Reiner is an industrial PC specialist at Beckhoff Automation. Edited by Emily Guenther, associate content manager, Control Engineering, CFE Media,

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Key Concepts 

  • The benefits of web-based human-machine interface (HMI)
  • The increasing performance of HMI hardware
  • The advances of HMI hardware options.

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Author Bio: Eric Reiner, IPC and MX-System Product Manager, Beckhoff Automation LLC.