© Antonio Guillem/Shutterstock.com

In automation, users demand a high degree of operability, reliability and safety. In addition to the hardware and software, this also includes the communication interfaces. With HTML5, access is platform-independent and possible via almost any end device. This also simplifies remote maintenance, as it can be carried out regardless of location via access authorization.

HTML5 also offers advantages from a security perspective. The Adobe Flash Player was initially established in web development. Like HTML5, it is used not only to display a website statically, but also to incorporate animations and interactions. However, because security vulnerabilities in Flash Player are repeatedly used in hacking campaigns, it is now considered unsafe and outdated software. Adobe is therefore discontinuing the player in 2020. As HTML5 is interpreted directly by the browser, it does not require any plug-ins and therefore offers better protection. In addition, no manual updates are required.

Different display in the browsers

In larger systems, operation and monitoring via a tablet PC is an option. © Phoenix Contact

From a visualization perspective, however, HTML5 is not a universal solution. Not every browser displays the new technology in the same way. The actual implementation of the open standard lies with the browser manufacturers, who have to implement the specifications. All major browser manufacturers are members of the W3C committee. However, as the companies involved compete for market share, the further development of the standards is a tense process between individual solo efforts and consensus. This is partly due to the fact that standardization is a lengthy process and often lags behind current requirements.

The disadvantage of a lack of portability is that HTML5 applications do not look the same everywhere. Incompatibilities occur between the different browsers. If an application is nevertheless always to be displayed in the same way, this increases the development effort. Classic automation applications require functions such as trend curves or alarm lists for visualization. HTML5 would not be able to display this without the layout functions JS and CSS. For a web HMI to work, several technologies have to interlock in the background. Web technology is developing very quickly. This inevitably leads to problems in automation, which tends to be geared towards longevity. The increasing complexity of applications requires more and more performance, while support for older versions is discontinued earlier. Accelerated technical change and security aspects are further accelerating this process.

Web panels for basic and high-end applications

Phoenix Contact offers compatible web panels with different touch technologies. © Phoenix Contact

With the new WP 4000 web panel family for implementing sophisticated applications and the BWP 2000 basic web panels for basic applications, Phoenix Contact offers high-performance HMIs. Both product series are equipped with an HTML5-compatible browser and therefore display all web-based visualizations that support the current HTML standard. The WP-4000 and BWP-2000 devices can therefore communicate with most modern PLCs and IPC-based controllers. They are connected via Ethernet to the respective controller, which runs an integrated web server. This hosts the pages with the application that are displayed on the panel. In systemic use, the web panels interact optimally with the PLCnext Technology ecosystem from Phoenix Contact. They can also be used as components with third-party software and control systems. The same applies to users who do not use an engineering tool but create the user interface themselves using HTML5, JS and CSS.

Dipl.-Betriebswirtin (BA) Julia Kurz, M.Sc., Product Marketing HMI, Phoenix Contact HMI-IPC Technology / am