Five essential criteria for effective mobile HMIs
Mobile human-machine interface (HMI) strategies should consider security, ease of use, level of access and detail, and collaboration when bringing HMI interfaces from the control room to the plant floor.
Placing process control information on mobile devices for engineers, operators, managers, or maintenance technicians is becoming a necessity to enable digital transformation and elevate the performance, productivity, and safety of facility operations. Creating an effective mobile strategy is critical to the success of projects and operations because it helps balance the need for flexible access to operations technology (OT) information with information technology (IT) safety and security requirements.
To select the right combination of technologies and tools, organizations need to consider essential criteria such as security, ease of use, level of access and detail, and collaboration. An effective mobile human-machine interface (HMI) strategy evaluates how to bring HMI interfaces from the control room to the plant via web browsers on phones, tablets, or rugged laptops.
Different users across the organization will expect to have access to different information. The strategy for mobile HMIs requires a plan for addressing the needs of all mobile users regardless of their role.
The strategy should also consider what level of collaboration is needed between users. Accessible collaboration tools can enhance the mobile HMI experience by providing those different users with better ways to share information with each other. When developing an effective mobile HMI strategy, consider the five criteria below.
1. Native integration
Before selecting specific technologies, organizations must address IT and OT concerns to ensure a smooth path to implementation. One of the largest OT concerns is the required engineering-for initial and for ongoing configuration maintenance to keep system synchronized. An emerging capability in this area is native integration. Native integration means less engineering work because the process control systems and mobile technologies are designed to share and securely transfer information without requiring duplication of the system configuration. For example, graphics, alarms, trends, and real-time data from an operator workstation can be automatically viewed in a web browser on mobile devices without having to reconfigure the control system on the mobile platform.
Native integration among systems and technologies also enables more straightforward tasks for the facility’s IT group. Having mobile architectures that employ similar interoperability, security levels, and communications simplifies implementation. For example, using similar architectures can be mean a simpler setup, optimizing port usage, and making it easier for IT to track which ports are being used.
After evaluating implementation plans, organizations can then compare specific technologies, remote operator stations, HTML5-ready mobile HMIs, and mobile applications, and how each technology contributes to their ideal mobile HMI strategy.
2. Remote operator stations
Remote operator stations extend (full or limited) control outside of the control room, to the plant floor, and beyond. This interface can be a full-featured tablet or hardened laptop that gives a full view and defined control to a team member. It resides on the control network or the demilitarized zone (DMZ) to give a mobile team member the same power and visibility as an operator in the control room.
A remote operator station can be particularly useful as part of a mobile HMI strategy, especially when facilities are running with a small staff and operators must be mobile. They also provide full operator access in the field, allowing the mobile worker to perform tasks such as confirming manual steps in a batch process, performing commissioning, and bringing equipment back online.
With full access to real-time data, diagnostics, trends, alarms, and operator screens, and traditional operating tasks, operators and technicians can commission devices locally, troubleshoot, or execute work orders while in the field. This allows tasks that required constant two-person communication between the central control room and the field such as loop checkout or valve stroke tests to be performed by one person.
Secure, scalable, and reliable communications enhance collaboration by removing misunderstandings and oversights that can occur when people interpret data from different sources. Applications also allow field workers to record their process observations directly into the system, thereby avoiding transcription errors.
A major concern with a remote operator station is whether to allow operational interactions from a mobile device—and if allowed—should there be specific, mobile device limitations? For example, does location matter? What if the device is offsite? Mobile, view-only approaches provide alternatives for these types of concerns.
3. HTML5 mobile-ready HMI
An HTML5 mobile-ready HMI is an HMI display built on HTML5 technology and is thereby accessible on mobile devices and computers, without needing to duplicate the display configuration on the mobile platform. It provides display portability and ease of use to a facility’s HMI plan by showing control room displays on a web browser. This enables personnel to see the same data and graphics securely as operators in a facility remotely, which can help ease collaboration between control room personnel and by remote personnel.
With an HTML5 HMI, any device with a browser—such as mobile phones, tablets, laptops, and operator workstations—allows remote or field users to see the same information and graphics as they would in a control room. The ability to easily and securely view this material on-demand from a browser enables people to make informed decisions at any time and from anywhere.
While mobile access to operations data can be limited to read-only, with cybersecurity built-in, by enforcing strict user permissions or ensuring only authorized personnel can access specific data depending on role and other factors such as location. Additionally, access from mobile devices can be limited to connectivity from business networks that are isolated from the control network by firewalls.
The HTML5 mobile-ready HMI gives users the same secure data access and analysis power a full operator station can provide, the flexibility and convenience of mobile access, and collaborative tools—without the security risks of making changes to control and operations.
4. Mobile applications
With tailorable, view-only data access, mobile applications are broadly used as secure technologies designed to encourage personnel to remain informed and engaged regardless of location. This mobile HMI option allows more personnel deployment and collaboration.
Mobile applications provide secure access through Google Android and Apple iOS devices. Workflows are streamlined with data being combined from multiple sources across the enterprise into simplified, consolidated mobile views that are intuitive to navigate.
This mobile application option is read-only, with a predefined level of access and detail. Users can view simplified lists of key real-time data, trends, and alarms. One benefit of this option is it raises situational awareness by providing quick access to alarms in context with process information, and notifications for critical alarms can be instantly sent to users.
These applications also strongly support personnel collaboration. Workers in and outside of the facility can share data and troubleshoot in real time, sending screenshots, links, messages, and emails with intuitive native mobile app functionality. Knowledge sharing and leveraging subject matter experts around the world enables faster and more accurate decision-making.
As with the HTML5 HMI, the mobile application accesses data via a mobile server that resides on the business network, so access to the control system is isolated by multiple firewalls between the business network and the control system network. User authentication, device whitelisting, read-only access, and data encryption further promote secure connectivity.
5. Always consider total cost of ownership
While many technologies provide potential solutions, the ideal solution offers a strong lifecycle value that balances easy, low-cost upfront implementation with security and minimal long-term engineering. The success of this strategy depends on choosing a solution that matches OT and IT strategies and that personnel can incorporate to daily operations.
Whether a remote operator workstation, an HTML5 mobile-ready HMI, or a native mobile application, these solutions can be securely and easily integrated into daily processes and work practices, to yield the desired productivity, performance, and safety improvements.
Mariana Dionisio, Camilo Fadul, and Cindy Scott are DeltaV strategy leaders for mobility and HMI design for Emerson Automation Solutions. Edited by Emily Guenther, associate content manager, Control Engineering, CFE Media, email@example.com.
KEYWORD: Human-machine interface (HMI)
- How to implement an effective mobile HMI strategy
- The benefits of having a mobile HMI strategy.
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