HMIs Are Not iPhones: HMI Upgrade Considerations

Summary

In the consumer world, each year ushers in phones, televisions and other technologies that are progressively better and often cheaper. At the very least, users expect a generally improving price/performance ratio. These same trends track in the industrial automation world, although usually at a slower and delayed pace. But because industrial HMIs share similarities with the smartphones and tablets used by consumers every day, and represent a main way operators interact with equipment, these devices undergo an additional degree of scrutiny by users.

Industrial automation specifiers are right to consider at what point diminishing returns indicate a product has reached peak maturity. For industrial products, new and convenient features can be interesting, but users tend to be concerned more with certain basics such as ease-of-use, cybersecurity and a futureproof path forward.

Operators used to frequent updates to their personal consumer electronics should understand how industrial HMI upgrade strategies are different. Specifiers looking for next-generation human-machine interfaces for their machinery and manufacturing equipment will find that advances are still being made both in the foreground and behind the scenes, making industrial HMIs easier to use and better in tangible ways.

Deciding when new is better

Typical consumer electronic hardware is progressively improved with better displays, increasingly capable processors, faster execution and more memory. These result in more responsive operation, and the ability to run software with increased functionality. Due to constantly improving manufacturing methods, sometimes performance advantages are realized in conjunction with a price decrease. Therefore, consumers frequently upgrade their personal electronics.

While performance benefits are also an important part of the reasoning for upgrading industrial HMI solutions, there are other factors to consider, and HMI suppliers need to carefully address certain issues specific to industrial use, such as those associated with form factors and longevity.

For example, while it may be fine to change the size of a next-generation phone or TV, an HMI specifier is building equipment that lasts years or decades, so they need the physical form factor to remain consistent. HMI suppliers can support this need for standardization by ensuring the overall bolt-in form factors remain largely the same to the greatest extent possible, regardless of changing display size.

There can are challenges with this approach, such as when common displays transitioned from a 4:3 ratio to a more modern ratio like 16:9, or when users are demanding smaller and larger sizes than have been previously available. However, experienced HMI suppliers listen to their users and will offer a consolidated portfolio of the most popular sizes, while maintaining uniform installation sizing.

Other hardware upgrades are welcome additions for new designs, while not impacting older retrofits. This is especially the case when additional Ethernet and USB ports are added, providing more design options to segregate networks for security or to add external devices. Other hardware features that users have come to accept as standard must be preserved, such as NEMA 4/4X ratings, 12/24VDC power inputs, serial ports and SD card ports.

Many other developments are vitally important, but they may not be immediately or easily recognized.

Behind the scenes improvements

The display size, look-and-feel and responsiveness of an HMI are immediately noticeable by users. But there are a host of crucial details which must be incorporated into software and firmware to fully modernize an HMI which are also very important. In particular, secure remote connectivity is a top feature many users now require. This can take many forms, such as an HMI that can host displays via web browser connections, a dedicated mobile device app able to connect with the HMI, FTP data transfer, and email.

Other features of modern HMIs include:

• Compatibility. Users require software to remain significantly compatible with older versions so they can avoid costly coding and configuration rework. This can be tricky to do well because balancing support of legacy code with the need for new functionality and forward-looking flexibility is difficult.
• Cybersecurity. Some vendors may try to add modern cybersecurity provisions as superficial patches, but best practice is to incorporate cybersecurity at the fundamental development level, which requires deploying updated firmware and software.
• Network Time Protocol (NTP). As HMIs are being called upon to do more, such as provide accurately timestamped alarm and event logging, NTP is necessary to provide proper synchronization among all connected devices.
• Secure communications. Connectivity among multiple on-premises and cloud-based resources has become extremely useful for many applications. Updated platforms need to support secure versions of popular communications protocols, including SMTPS, HTTPS and MQTTS.
• Networking. Many HMIs include drivers to communicate with a variety of PLCs, but fewer can perform more advanced functions, such as acting as a data bridge between different PLCs, or aggregate data from multiple HMIs, instead of adding communications load to the source PLCs.
• Configuration and programming advances. A modern integrated development environment will support user libraries, project migration, database import/export, simulation and more to minimize designer effort.

HMI upgrades that provide real benefits

For completely new “clean sheet” projects, most designers are free to choose the latest HMI offerings. But for anyone performing a retrofit or an automation upgrade, or supporting a legacy installation, the choice of how and when to upgrade an HMI becomes more relevant.

Designers will be considering the following attributes, in a priority order suitable for their application:

• Selection: A concise yet comprehensive range of sizes covering small to large, with the ability to retrofit into existing cutouts where possible.
• ​Capability: Improved processing speed, more memory, upgraded visualization and added performance characteristics.
• Easy-of-use: Free software, with numerous tools and drag-and-drop options, to simplify the development, migration, simulation and deployment of applications.
• Industrial internet of things (IIoT): Modern HMIs with built-in cybersecurity provisions are the right answer to take advantage of the latest communication protocols and methods in a secure fashion.
• Value: While the preceding technical points are of great importance, part of any HMI decision will always rely on a favorable price/performance ratio.

Industrial HMIs are a relatively mature part of the manufacturing and process automation landscape. However, experienced suppliers are working to make the upgrade path straightforward and secure to deliver maximum value and performance.

<sub>All figures courtesy of AutomationDirect

This piece originally appeared in the December 2023 issue of InTech digital magazine.</sub>