Standardizing multi-touch HMI hardware

Cost control for manufacturing applications can be as important as machine control. As a result, cost-conscious manufacturers may hesitate to consider new automation and control technology investments. Upgrades to human-machine interface (HMI) hardware is no exception.

Industrial vendors and users often agree that a standard HMI should include a durable touch-screen panel and the opportunity to include options such as a CPU for control as well as buttons and keys for specific functions such as a safety E-stop. Additional lighted buttons around the panel can be included based on the machine’s functions to increase efficiency in specific industries such as plastics processing, packaging, and machine tools.

Manufacturers and automation companies often disagree whether it’s more logical to implement single-touch panels or whether to use multi-touch technology. Industrial multi-touch panels have been on the market for many years now and present operators with more capabilities, including the ability to zoom, swipe, and navigate controls with 3-D HMI software.

Although "new" often translates to more expensive, that’s not always the case with HMI hardware. Depending on the manufacturer, multi-touch panels are often less expensive than their single-touch counterparts when comparing screen size, build, and processor performance.

Multi-touch panels also cut costs by future-proofing operations. It’s possible to implement a multi-touch capable panel and operate it in single-touch mode with the option to upgrade to newer multi-touch software in the future. As a result, no additional hardware changes will have to be made and it will be much easier to retrofit already-deployed HMI systems to multi-touch software at a later date. 

Upgrading HMI hardware

Multi-touch panels provide functional improvements and efficiency increases for machine operators including:

• Ability to intuitively find important equipment status notifications
• Rapidly scroll through multiple menu screens
• Swipe across spanning graphical representations of machine lines
• Additional safety features such as two-hand or two-finger touch to activate certain modes of operation.

These interface capabilities have been available for years with smartphones and tablets. With the advances in multi-touch software as well as smartphone and tablet capabilities, machine control, and visualization, applications also are available for mobile use through HTML5-enabled HMI software. HTML5 allows HMI screens to automatically transfer to tablet or smartphone sizes. Previously, new programming was required for screens to appear in another size device.

When using web-based HMI screens, it’s possible to make machine HMI screens available on mobile devices. The growing adoption of multi-touch panels for industrial applications means the same mobile devices used to check work email or use for general business purposes can provide greater functionality for machine monitoring and control.

For years, multi-touch-capable panels and software packages have proven to be just as reliable as traditional HMI systems, which is translating to a higher market share on production floors.

High-quality industrial displays can have a lifecycle of a decade or more. Opting for a single-touch panel over a multi-touch panel in the short-term could put a manufacturer in a tough position in the future.

Further advances in multi-touch and web-based HMI software will likely create a quandary when deciding whether it’s better to remain locked into a less functional system or if it’s time to upgrade single-touch panels that still function. A better strategy would be to implement multi-touch panels and set them in single-touch mode until the application requires the HMI’s full capabilities. 

Panel PCs and computing power

Another trend is to reduce overall equipment and machine footprint. It’s important to ask if it’s necessary to install a space-saving panel PC to eliminate a separate industrial PC (IPC) from the control cabinet.

A multi-touch panel PC could be the right strategy, but it might not be ideal for all applications. Panel PCs should possess enough processing power, random access memory (RAM), and onboard diagnostic tools to provide an appropriate level of performance for the application.

The benefit of a passive multi-touch panel and separate IPC setup is so the panel can be used for years even if the IPC is upgraded to a more powerful model. The process also is easier to replace a passive panel if it’s damaged. Passive panels and panel PCs with an integrated CPU can be fully enclosed units for arm or pole mounting, eliminating the need to create cutouts in separate HMI enclosures.

A strategy to reduce panel cabling is to use one cable connection technology. Using a simple, low-cost hardware adapter, IPCs can send a digital visual interface (DVI) signal, USB 2.0 signal, and power to a panel 100 m away. This saves even more space on the production floor while providing the same flexibility to update HMI hardware in the future. 

Advanced security for integrated HMIs

An open PC-based platform is ideal when integrating an HMI. The PC-based controller can run the HMI software as easily as the programmable logic controller (PLC) and motion control projects. For vertical communication considerations, IPCs and panel PCs are well suited for open-platform communications unified architecture (OPC UA) communication. This builds in secure and encrypted data transmission for cloud and edge computing scenarios.

System security is often implemented in software and networking, but new HMI hardware can prevent unauthorized on-site use and errors. Using radio-frequency identification (RFID) chips installed in employee badges or key cards, for example. HMIs equipped with an RFID reader can authorize access to select users based on their job responsibilities.

Therefore, only certain machine functions are available to employees in the HMI depending on their position and responsibilities. RFID can serve as a more efficient and effective security gatekeeper that does not require manual entry with usernames and passwords.

It’s a smart strategy to choose multi-touch HMI hardware and ensure the panel PC provides enough processing power for the long term. By standardizing multi-touch panels today, a factory can prepare itself to adapt to advances for years to come.

Eric Reiner, industrial PC product specialist, Beckhoff Automation. Edited by Emily Guenther, associate content manager, Control Engineering, CFE Media, eguenther@cfemedia.com.

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KEYWORDS: Human-machine interface (HMI)

The benefits of upgrading HMI hardware with multi-touch panels

Panel PCs and computing power Increased security with upgraded HMI hardware.

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