Cost control is just as important as machine control in manufacturing. Therefore, manufacturers who are particularly sensitive to costs may hesitate to invest in new automation and control technologies. Upgrading human-machine interface (HMI) hardware is no exception.
Suppliers and users generally consider a standard HMI to include a durable touchscreen panel, a CPU for control, and buttons and controls for specific functions such as emergency stop. Depending on the machine's function, it may also include illuminated buttons arranged around the panel to improve efficiency in specific industries such as plastics processing, packaging, and machine tools .
Figure 1: The multi-touch panel allows users to zoom, switch, and navigate via 3DHMI software. Image source: Beckhoff.
Manufacturers and automation companies often disagree on whether implementing single-touch panels or multi-touch technology is more logical. Multi-touch panels for industrial use have been available for years, offering operators more functionality, including zoom, toggle, and navigation controls using 3DHMI software.
While "new" usually means a higher price, this isn't always the case for HMI hardware. Depending on the manufacturer's requirements, multi-touch panels are generally cheaper than single-touch panels when factors such as screen size, build costs, and processor performance are taken into account.
Multi-touch panel operation is unlikely to become obsolete quickly, thus reducing costs. Panels supporting multi-touch can be deployed but run in single-touch mode, allowing for future upgrades to newer multi-touch software. Since no additional hardware upgrades are required, upgrading an existing HMI system to multi-touch software is relatively easy.
Why upgrade HMI hardware?
Multi-touch panels can provide machine operators with functional improvements and efficiency enhancements, including:
● It allows you to intuitively find status notifications for important equipment;
● Quickly switch between browsing multiple menu screens;
● A graphic representation of a machine line;
●Additional safety features, such as two-hand or two-finger touch, to activate certain operating modes.
Similar interface functionalities have been used on smartphones and tablets for years. With advancements in multi-touch software and the capabilities of smartphones and tablets, as well as machine control and visualization, applications can also be used on mobile HMI software that supports HTML5. HTML5 allows the HMI screen to automatically adapt to tablet or smartphone sizes. Previously, if you wanted to display on devices of different sizes, you needed to reprogram the screen.
Using web-based HMI screens, the HMI displayed on the machine can also be displayed on mobile devices. In industrial applications, the increasing use of multi-touch panels means that mobile devices, typically used for checking work emails or general business purposes, can offer more functionality for machine monitoring and control.
Over the years, multi-touch panels and software packages have proven to be just as reliable as traditional HMI systems and are gaining a larger market share in production floor monitoring.
High-quality industrial displays can have a lifespan of ten years or more. Choosing a single-touch panel instead of a multi-touch panel for short-term gains may cause significant inconvenience for users in the future. Further developments in multi-touch and web-based HMI software may create confusion when deciding whether to stick with the existing, less feature-rich system or upgrade a still-functioning single-touch panel. A better strategy is to deploy a multi-touch panel and configure it for single-touch mode until the application requires the full functionality of the HMI.
Figure 2: HMIs are configured to meet industry applications, such as integration with industrial PCs, ruggedization, flushing, glove-wearing, or daylight visibility requirements.
Tablets and computing power
Another trend is reducing the overall footprint of equipment and machinery. It's important to consider whether it's truly necessary to install space-saving tablets to eliminate the need for a separate industrial computer (IPC) in the control cabinet.
Choosing a multi-touch tablet might be the right strategy, but it may not be suitable for all applications. The tablet should have sufficient processing power, random access memory (RAM), and onboard diagnostics to provide appropriate performance for applications.
The advantage of passive multi-touch panels and independent IPC devices is that the panel can be used for many years even if the IPC is upgraded to a more powerful model. Replacement is also relatively easy if the passive panel is damaged. Passive panels, as well as tablets with integrated CPUs, can be fully enclosed devices mounted on an arm or pole, thus eliminating the need for openings in a separate HMI housing.
The strategy for reducing panel cabling is to use single-cable connection technology. Using simple, low-cost hardware adapters, the IPC can send digital video interface signals, USB 2.0 signals, and provide power to panels up to 100 meters away. This saves more space on the production floor and also provides flexibility for future HMI hardware upgrades.
Figure 3: Touchscreens can eliminate the need for a separate keyboard in some HMI applications. When screen size, build quality, and processor performance are taken into account, multi-touch panels are generally cheaper than single-touch panels.
Security of integrated HMI systems
PC-based open platforms are ideal for integrating HMIs. PC-based controllers can run HMI software as easily as PLCs and motion control projects. Considering vertical communication, IPCs and tablets are well-suited for Open Platform Communication Unified Architecture (OPCUA) communication. This enables secure and encrypted data transmission for cloud and edge computing solutions.
System security is typically implemented in software and networks, but new HMI hardware can prevent unauthorized field applications and errors. For example, using radio frequency identification (RFID) chips installed in employee access cards or key cards. HMIs configured with RFID readers can authorize user access permissions based on job responsibilities.
Therefore, employees can only use some machine functions through the HMI, depending on their specific job and responsibilities. As a more efficient and effective security measure, RFID eliminates the need for manual username and password input.
Choosing multi-touch HMI hardware and ensuring the tablet can provide sufficient processing power over the long term is a wise strategy. Deploying standardized multi-touch panels allows factories to prepare for future developments.
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