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High-End Graphics for Small Devices

Enabling Consistent HMI Experiences from Portable, Handheld to High-Performance Panels

With the advent of mobile HMI devices, designers can benefit from a single CPU/graphics processing architecture that can offer hardware and software consistency from small handheld displays to full-sized HMI and IT systems.

CAMERON SWEN, AMD EMBEDDED SOLUTIONS

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In the industrial control and automation domain, continued advancements in human machine interface (HMI) technology are driving huge gains in productivity and usability. With each new generation of HMI systems, conventional “knob and button” operator controls are being phased out in favor of touchscreen interfaces that in many ways mimic the consumer smartphone/tablet experience.

These software reconfigurable multi-touch HMI panels are designed in part to reduce hardware dependencies between the control panel and the embedded system, allowing HMI panel designers to more easily modify the functionality of the system and enhance the interface over time—similar to the way in which smartphone designers have jettisoned most physical push button controls in favor of reconfigurable touchscreen interfaces. 

With this continued evolution toward touchscreen HMI panels, portable handheld HMI devices are emerging as a valuable complement to traditional fixed-installation HMI panels, giving system operators greater flexibility and mobility on the factory floor, with wireless connectivity to the central control panel. With support for consumer smartphone/tablet-like interfaces, operators can navigate these portable HMI devices much like they would their personal devices, using intuitive gesture-based input to navigate the GUI (Figure 1).  

Figure 1
Users in many fields such as industrial control increasingly expect their user interfaces to offer the same touchscreen experience they have become accustomed to through tablets and smartphones.

The advent of portable handheld HMIs has created a dilemma for HMI system designers, however. These designers are tempted to adopt mobile-optimized, low-power processing platforms for this specific class of HMI device, while utilizing higher-performing processor platforms for more graphics- and compute-intensive fixed-installation HMI panels. This approach introduces significant tradeoffs for HMI system designers and users alike. Here we’ll look at some of the pitfalls of this approach, and also the associated merits of Accelerated Processing Units (APUs) as a unified, scalable processing platform appropriate for both portable handheld devices and fixed-installation HMI panels.

The Problem with Bifurcation

Handheld portable HMI devices are frequently tethered (albeit wirelessly) to a central control panel. And although these portable systems are designed to be used independently of the central panel in a physical sense, operationally the portable device is designed to serve as a natural extension of the central system. In some cases, these wirelessly tethered devices are designed to visually replicate the master HMI display so as to enable an operator to carry the device through the production line without sacrificing visualization and/or management capabilities. As such, there are clear benefits in maintaining a single, scalable underlying processing platform across both types of systems to ensure a consistent look and feel between them. 

For the HMI system vendor, this single platform approach yields greater design efficiency and significantly leaner cost structures, enabling designers to develop and maintain a single unified software solution and hardware architecture that can be scaled across the full product line. These efficiencies are even more pronounced on the embedded x86 platform, given the inherent PC-compatibility and rich ecosystem of industry-standard, x86-optimized software, applications, operating systems and development environments available to designers. x86 support also contributes to greater interoperability with the enterprise IT network, which introduces additional benefits for applications such as security and antivirus, system maintenance and remote administration, helping to integrate factory floor and distributed control system communication with an IT infrastructure utilizing standard networking protocols. 

For HMI system operators, consolidating on a single processing platform helps provide a consistent user experience across handheld portable and fixed-installation HMI panels. This consistency may make learning and operating these systems, via a familiar GUI and feature set, faster and easier for users. The resulting productivity and precision control gains can be significant. 

High-Performance Graphics across the Board(s)

While lower-performing, mobile-optimized processors can be adequate for some handheld portable HMI devices, the graphics and CPU performance provided by these processors may not be suitable for the latest generation of integrated automation panels. The ability to scale to accommodate large screens at HD-caliber resolutions and additional management and control capabilities is elusive at best for this class of processors. This issue is considerably more pronounced for HMI devices and panels that utilize video and/or 3D graphics, the latter of which is becoming increasingly popular as a means to achieve 360 degree precision visualization for process automation. It is for this reason that HMI panel designers are increasingly seeking out processing platforms that support OpenGL, the multi-platform API for hardware-accelerated 3D graphics rendering. 

Video and 3D support also helps to facilitate consistent and accurate industrial system maintenance by minimally or untrained personnel, but these benefits are more easily achieved if the video and 3D graphics performance is stable and reliable. Video and 3D graphics that seize up in mid-operation can be frustrating at best and counterproductive at worst for users at every experience level.

APUs Powering Space and Power Efficient Mobile HMI Devices

With the aforementioned considerations in mind, APUs are a compelling option for distributed HMI systems that incorporate a diverse range of graphics-intensive handheld portable devices and high-performance fixed-installation panels throughout the factory floor. Offering x86 compatibility and the ability to scale from low-end portable to high-end system support in the same small physical footprint, APUs can help provide consistent, high-speed graphics processing—including video and 3D—at performance-per-watt ratios optimized to support power-sensitive, handheld portable HMI devices.

Through the combination of a general-purpose CPU and discrete-class GPU on a single die with a high-speed bus architecture and shared, low-latency memory model, APUs can offload computation-intensive pixel data processing from the CPU to the GPU. Liberated from this task, the CPU can serve I/O requests with much lower latency, thereby helping to improve real-time processing performance to levels that may exceed the capabilities of conventional processor architectures in many cases. The APU’s two-chip architecture—the APU and the companion controller hub and fully integrated SOCs on their way—also naturally help to simplify design complexity through a reduction in embedded board layers, helping to enable HMI device designers to achieve aggressive form factor goals for greater device mobility. 

The performance-per-watt gains enabled by some APUs ensure low power consumption and low heat dissipation, which can preclude the need for fan cooling within portable handheld HMI devices, and thus help to preserve board space, improve overall system reliability and limit system noise. With average power as low as 2.3 watts and thermal design power (TDP) profiles from 4.5W to 18W, AMD Embedded G-Series APUs, for example, can help equip HMI system designers to utilize highly compact system enclosures for portable handheld devices, and can help enable these designers to stay within the threshold at which passive cooling is an acceptable and typically favorable option. Passively cooled, ventless systems are the ideal end goal for portable HMI devices distributed throughout a harsh factory floor environment.  

With the additional versatility to apply the integrated GPU for high-speed vector processing and/or graphics processing as needed, HMI system designers utilizing APUs can better target both embedded headless designs and graphics-driven systems with a single processing platform. Overall, APUs can help provide a single, scalable platform that helps balance space savings, power consumption and cooling efficiencies with high-performance graphics capabilities to help provide consistent support for handheld portable HMI devices and high-end, fixed-installation HMI panels alike.

Hardware Virtualization and Multi-Screen

Another important consideration for developers selecting the underlying embedded processing platform for their single processing platform designs is support for hardware virtualization.  This enables multiple operating systems and their applications to run simultaneously, and independently, on the same processor for the purposes of enabling workload consolidation and the separation of functions. Support for hardware virtualization efficiently facilitates the integration of separate systems on the factory floor.

For its graphical elements and ease of programming, Microsoft’s Windows is the dominant operating system in HMI applications. However, for real-time operation, reliability and safety in control applications, real-time operating systems (RTOSs) such as Integrity from Green Hills Software are preferred. Virtualization enables Windows to run alongside deterministic real-time operating systems for HMI systems used in machine and process control applications on the same processor. And by accelerating the virtualization on the hardware, it helps to prevent the processing overhead of the virtualization from impacting the user interface or, more importantly, the real-time operation. The ability to use such virtualization to combine the functions of the process control with the mobile operator panel results in a system architecture that can be scaled for fixed or mobile HMI operations (Figure 2).

Figure 2
A unified scalable processing platform is made possible by the ability to closely integrate the functions of the process control, which depends heavily on real-time operation through the use of an RTOS, with a graphical user interface that can run on the same device using an operating system like Windows.

Multi-display capabilities are emerging as another important consideration for HMI system designers when selecting the underlying processing platform. With multi-display flexibility, a single processor could power the main screen as well as companion screens that could display manufacturing line data or analytic data from other systems distributed throughout the factory floor, for example. Multi-display capabilities can also facilitate panoramic display configurations for “wraparound” HMI panels and/or massive multi-panel overhead displays for long-distance viewing across the factory floor. 

Be it a single-screen, handheld portable HMI device or centralized multi-screen HMI panel installation, consistent and compatible high-performance graphics are paramount to system scalability and user-intuitive operation in industrial automation applications. APUs can help eliminate the need to bifurcate the underlying processing platform to accommodate these two types of systems, helping to enable design and operation efficiencies via a unified embedded hardware architecture.  

Advanced Micro Devices
Sunnyvale, CA.
(408) 749-4000.
[www.amd.com].