How to Build a Better HMI: Create the Screen That Runs the Plant

Building a successful HMI platform to support manufacturing requires the right combination of hardware and software. The system needs to bring together IT and OT in order to gather, present, and analyze data from smart equipment.

We spoke with Rockwell Automation about what it takes to create a successful HMI system for manufacturing. Their responses came as a team effort, with four experts weighing in on the process to build a better HMI. The experts who chimed in include Sue Burtch, visualization software marketing manager, Joe Geigel, visualization hardware marketing manager, Tom Jordan, ThinManager marketing manager, and Chris Mason, visualization hardware platform leader.

Design News: What are the components of an effective HMI in plant operations?

Sue Burtch, Visualization Software marketing manager: An HMI system must be able to converge hardware and software components into a single, seamless system that an operator can use with ease to monitor and control plant-floor equipment. The system also must be able to converge IT and OT to fulfill its role of gathering, presenting, and analyzing data in today’s smarter, more data-driven operations.

How all these elements come together to create your HMI system depends on your application’s unique needs. For a single machine application, an electronic operator interface (EOI) terminal and machine-level HMI software can suffice. Larger applications and plantwide process control systems may need a mix of industrial PCs, terminals, and mobile devices, along with site-level HMI software.

However, operators are increasingly realizing the benefits of centralized HMI architecture for applications of all sizes. This approach uses one server to deliver HMI and other content to thin-client terminals, mobile devices, and industrial PCs throughout your plant. A centralized HMI architecture reduces the number of operating systems on the plant floor that need to be updated and maintained, which can reduce downtime risks. It also allows you to store content centrally, instead of on several plant-floor devices, to enhance security.

DN: What are the qualities that are critical to making the HMI a visualization system for a plant?

Joe Geigel, Visualization Hardware marketing manager: Scalability and usability are both crucial. Your HMI platform should be able to scale to meet the needs of your operations today and in the future. And for optimal usability, the platform must be able to present the right information to the right person.

With a centralized HMI approach, you can customize the content delivered to a device based on who logged into that device and what their role is. You can even deliver non-HMI content, such as a live camera feed, to give them line-of-sight into a process and help them better do their job.

Mobility is also increasingly important. Modern HMI software can turn smartphones and tablets into operator interfaces. And a centralized architecture that uses location-based mobility allows you to do even more. Upon entering a defined location or scanning a location ID, like a QR code, staff can access specific information that’s relevant to where they are and what they’re looking at, so they can be more informed and make better decisions.

Security is essential in any HMI system. If you are deploying a centralized architecture, for example, your content management software must be designed for the OT space with IT security in mind. It should use access groups and permissions to restrict access to assets. And it should require multi-factor authentication when establishing location-based mobile connections.

DN: How does HMI software fit into a complete visualization system?

Sue Burtch: Modern HMI software helps make data-driven operations possible. How? By integrating with your plant-floor hardware and software to provide instant access to data. By contextualizing that data into meaningful information that staff can understand and act on. And by presenting information with easy-to-understand graphics and helping workers focus their attention on alarms and other important details.

The software also improves how your staff interacts with data, such as by using touch gestures to scroll through data and flip through pages. It also supports the latest technologies that enable digital transformation, such as cloud computing, virtualization, and AR/VR technologies.

When modern HMI software is combined with thin-client management software, you unlock even more possibilities to improve how people work. Location-based mobility and access to additional information like camera feed improve the situational awareness of staff. Also, terminal-to-terminal shadowing allows one person to view on their device the session from another person’s device. Imagine a technician – at a moment’s notice and from anywhere in the plant – being able to shadow on their mobile device an operator’s terminal. This could set a new standard for troubleshooting and issue resolution times.

DN: What is the role of modern PCs and thin clients in the HMI visualization system?

Tom Jordan ThinManager marketing manager: Industrial PCs play an important role on the plant floor, but “white box” PCs are on their way out. Their use of rotating media, coupled with commercial-grade construction makes them prone to failure on the plant floor.

Thin clients offer improved reliability and reduced maintenance because they have no moving parts. The devices are also centrally managed, so you can install your HMI software once in a thin-client server and then deliver it to all your thin clients. Thin clients also reduce security risk at the local device level. They don’t provide access to the system beyond what’s displayed on the screen, and they don’t provide a point of entry for viruses.

New solutions like compact box PCs offer a best-of-both-worlds approach. These PCs, small enough to fit in the palm of your hand, can run on a Windows OS or switch to run on thin-client management software. This allows you to use the device as a PC today and as a thin client in the future. It also offers other benefits, like the ability to load applications from a PC if a central server goes down.

DN: What engineering skills are required for developing this system? Software engineering, systems engineering, knowledge of plant systems, knowledge of HMI tools?

Chris Mason, Visualization Hardware Platform leader: The answer is all of the above. The challenge is that most engineers don’t come out of college equipped with all these skills. Instead, they spend several years building their competency across multiple functions. And as we know, experienced and highly skilled employees are harder than ever to find and retain today.

Fortunately, the same technology that’s creating more connected and information-driven operations is also helping ease system development. For example, modern HMI software that integrates with your control system can directly access and reference tags in the controller. This reduces work for the system developer by eliminating the need to create HMI tags. It can also help increase accuracy in state tracking and alarm time stamps. The ability to store and reuse device faceplates and other objects in a library can also help developers more quickly deploy interfaces across machines, lines, and plants.

DN: What quality-control elements are required to create a successful HMI system?

Joe Geigel: Modern HMI software that’s designed to integrate with your other production systems can give you access to not only real-time controller information but also information stored on the plant floor. This can empower staff to better analyze the production, track quality, optimize equipment performance, and more.

Alarming is another crucial element of a successful HMI system. Your HMI software should optimize how staff sees, understand, and respond to alarms. Software that overlays alarm information on trend data, for example, can help staff speed up troubleshooting by connecting alarm occurrences with data-point values. Device-based alarms can also more quickly detect alarm conditions and give workers more accurate alarm time stamps than tag-based alarms.

Your HMI software can even take on a more proactive role in alerting staff of alarms with alarm escalation. For instance, the software can notify an operator of an alarm with a traditional HMI alarm and smartphone text message. If the operator is unresponsive, or if conditions worsen, the software can then send the text message notification to other plant personnel. The software can even trigger your plant’s emergency monitoring system to begin an evacuation if conditions reach a critical threshold.

DN: What are the maintenance and update plans required to keep the system working well over time?

Chris Mason: Thinking about the lifecycle of your hardware early in the development and specification stage can help you reduce maintenance demands in the long term. Solutions like stainless steel graphic terminals that are National Sanitation Foundation (NSF)-certified can help simplify cleaning and minimize contamination. And using thin clients in place of PCs can significantly ease the maintenance, expansion, and replacement of your HMI terminals.

If you opt for a centralized architecture, redundancy is an important consideration. Adding a second server to your architecture can give you a full server failover option to keep your HMI system in an “always-on” state and help reduce the risk of downtime.

Even the vendors you choose can have an impact on your HMI system’s lifecycle. Some vendors offer more generous long-term support for their HMI hardware than others and are more transparent in their reporting of security vulnerabilities. These points of differentiation can be easily overlooked in the buying stage, but they can help you better manage risks in your operations and extend the life of your system.

Rob Spiegel has covered manufacturing for 19 years, 17 of them for Design News. Other topics he has covered include automation, supply chain technology, alternative energy, and cybersecurity. For 10 years, he was the owner and publisher of the food magazine Chile Pepper.