HMIs provide the driver for improved machine design
How many HMIs today are specified solely on the basis of screen size and price? While these factors are undoubtedly important, Omron's James Riley argues that a re-evaluation of the power and capability of modern HMIs could yield important benefits and begin to drive a fundamental change in the way machines are designed.
It is often said that an HMI provides a window into the machine, providing not just a control interface for the operator but also a useful tool for diagnostics and maintenance. Perhaps this was so in the days when the HMI was really only dealing with data to and from the PLC, but today data can come from many and varied sources. An HMI installation that doesn't recognise this is really providing little more than a porthole into the machine - a very narrow view indeed.
The differentiation between PLCs, HMIs, PCs and panel PCs is often been grey at the best of times, and the boundaries are continuing to blur. As these distinctions between technologies break down, we need to rethink what capabilities need to be offered within an HMI. Increasingly that means looking not just at the traditional role of visualisation, but also at data transformation and the real relationship between the machine and the human.
Traditionally presentation and visualisation have probably been the prime reasons HMIs are specified as part of a machine control system, replacing keypads, switches, indicators, panel meters and individual control panels with a single, sleek, attractive and user-friendly control interface. It is no surprise, then, to see so much of the marketing material for these products devoted to screen size, numbers of colours, pixel counts and graphics capability. Really, though, the highest levels of performance in all of these areas should today be taken as a given. Every HMI worth its sort should be capable of presenting crisp, clear, high-resolution graphic representations of just about any control element, perhaps with the added benefits of functions such as trending graphs and accurate metering. So what other aspects of presentation and visualisation could machine builders consider in order to add value to their machine designs?
Increasingly HMIs are building in capabilities for rich media such as photographs, videos and PDFs. Displaying photographs instead of simple graphic representations can bring increased clarity for the operator. The ability to display live video might show where a jam has occurred, leading to increased productivity. The growing deployment of Ethernet-enabled video cameras on machines and production lines can support in key areas such as work-in-progress visualisation and product traceability, as well is in the more traditional areas of machine vision, and the modern HMI can provide the perfect local medium to display such video. Further, technical videos that complement printed manuals to show how to replace or install key components could significantly increase machine availability. At the same time, the need for printed manuals themselves could be reduced by the ability to display PDFs, simplifying maintenance and reducing downtime.
We can go further, too, as we look towards improved presentation. Today's graphics are good but in the near future we'll see even more realistic graphics through the addition of physics engines to display representations of lighting, inertia and other physical phenomena. At the same time, the gesture control capabilities that we take for granted in tablets and smart phones are also coming to HMIs, further aiding in presentation and usability.
All of these developments in presentation are important, but they are still extensions to and enhancements of the traditional role of the HMI. Perhaps of more importance to machine builders looking to add value to their machine designs is the ability of modern HMIs to manage data flow and to perform transformations on that data. Today, data comes not only from the HMI itself and from the PLC which forms its primary connection, but also from drives, instruments, other automation components, embedded databases, higher level controllers and the wider enterprise. When the HMI can manage that flow of data, and transform data so that it is usable by different people, controllers and databases - all with different requirements - throughout the machine, the production line and the wider enterprise, then manufacturing systems can begin to realise real productivity benefits. Machine builders who embrace the importance of data and the ability to perform transformations on it from within the HMI will have a significant competitive advantage.
Much of this capability is already available even within many mainstream HMIs built on today's high-performance Intel microprocessors. This power isn't just there to drive the graphics engine; it brings increased processing capability to the HMI in its own right, delivering greater ability for data transformation and impacting on the way HMIs are specified. This added power doesn't necessarily imply a panel PC or an HMI with built-in PLC - although that might be exactly what you want in a given application - but it does mean that the HMI can do far more in its role as a gateway between the user and the machine control system.
Alongside presentation and data transformation, a third axis of development within HMIs is vision. We have already discussed the growing importance of vision focused inside the machine, but what about looking outwards? In the same way that tablets and smart phones build in cameras, why not the HMI? This vision capability could quickly bring significant benefits in machine design: energy saving is just one simple example - if nobody is standing in front of the HMI, does the screen really need to be on? Further, in-built cameras could aid in security by providing visual authentication of different levels of operator and maintenance personnel. The same cameras could also help to identify causes of error in the machine by providing a visual audit trail of operator actions.
These are capabilities that are just around the corner in the HMI development roadmap, but once we embrace outward looking vision and make the machine aware beyond its own boundaries then we open up the potential for so much more. Face detection and recognition capabilities are now taken for granted in consumer cameras, so why not industrial HMIs? Consider for example that Omron's own OKAO 'face vision' technology is already in use within consumer devices providing detection and recognition of faces, expressions and gestures, regardless of the direction the person in question is looking or facing.
Extending this technology to industrial HMIs is a logical next step, and could fundamentally change the relationship between the machine and the operator. Consider, for example, the ability of the machine to recognise whether an operator or a maintenance technician was approaching its guard boundary, and either stop itself or slow itself to a safe speed as appropriate. Or a machine that could recognise behaviour and intention, and so be alert to problems before they happened. Or indeed a machine that understood gestures without the operator having to physically touch the HMI screen.
Of course much of this is for the future, but modern HMIs such as Omron's new NA series are built on platforms using standard Intel and Microsoft technologies that will enable such futuristic-sounding concepts to be introduced as part of a steady product evolution. This same platform is already allowing machine builders to ask questions such as whether the operator needs to be constantly tethered to the panel mounted HMI or whether many monitoring and operational functions could be mirrored on tablets. Omron's HMI app, for example, recognises the important role of the physical HMI as a data hub, but extends operator interaction beyond the boundary of the machine.
The ability to fully realise the benefits that HMIs can deliver today and will deliver tomorrow of course places an emphasis on ease of programming and integration with the wider control system. If the whole is to be more than the sum of the parts, then that surely implies that the control system should be programmed and set up as a whole, and built on common technology standards. This is the approach that Omron has taken with its Sysmac concept, with Sysmac Studio software providing a single unified environment that gives the machine builder control over the complete automation system (control, motion, safety, vision, networks, robotics, HMI, databases, RFID and more), and which integrates configuration, programming and monitoring in a simple, intuitive interface. Within the HMI in particular, this extends to the ability to incorporate intelligent application gadgets, and to publish and share these just as you would with PLC-style function blocks.
The HMI has always been the face of the machine, and continues to provide the primary bridge between the user and the machine control system. But for machine builders who want to add maximum value to their machines and enhance their own competitive advantage, there are already enormous benefits to the reaped from a greater focus on the presentation, data transformation and human interaction capabilities of modern HMIs, with platforms that deliver impressive capabilities today and which will evolve to deliver even greater benefits in the future.
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