Advice from integrators on HMIs, wireless, cloud use, thin clients
System integrators from companies that won 2017 System Integrator of the Year recognition were asked to provide advice on human-machine interface (HMI) software screen design, wireless and cloud technologies for Industrial Internet of Things (IIoT), and on project-related advice, which yielded thin-client advice. Providing advice on these topics are:
- Jordan Gass, control systems developer
- Loren Schmidt, senior control systems developer
- Marty Van Der Sloot, division manager, manufacturing IT, Interstates Control Systems
- Will Aja, vice president of customer operations, Panacea Technologies Inc.
CFE Media: What advice can you provide about human-machine interface software design?
Gass: A high performance HMI gives operators the critical information they need to know to safely and effectively do their jobs without being overwhelmed with information and animations that don’t add value to what they are trying to accomplish. Elements common to a high-performance HMI include:
1. Judicial use of color. Too many colors can overwhelm a person when trying to view the process from a high level. Colors like red, yellow, and orange attract an operator’s attention, so should be reserved for abnormal or alarm conditions. Operators can more easily note an area with abnormalities by incorporating a neutral color background, like gray, and highlighting abnormal conditions with brighter colors.
2. Limited animations and moving parts. These may not provide value and may only serve to draw operator attention away from important information.
3. Graphs and "analog sliders," which are easier to understand at a glance than numbers (important for precision).
4. Alarm management. Determine importance of alarms, which should be highlighted, and in what ways. This will serve as a way to avoid overwhelming operators with alarms that may be of little value or serve as notification only. Major industrial disasters can be attributed in part to an HMI and alarm management system that did not highlight critical information at the critical time. An improved design in these systems could have allowed the operator to quickly notice substandard performance, and quickly take action to prevent the catastrophe.
Schmidt: Standards need to be consistently used within a human-machine interface. Operators find comfort in familiarity. When something deviates from the standard (a one-off design), it adds an area to the HMI where the operator has to deviate from standard thinking, and has to interpret and evaluate the screen more thoroughly. This causes slower reactions to anything that needs action, especially something pertaining to quality and safety.
Aja: The evolving ISA standards around high performance HMIs [ISA101, Human-Machine Interfaces] have created quite the stir in the industry, especially in the process world. Most process engineers will scoff at the idea of not having a P&ID [process and instrumentation diagram] as the backdrop for control screens. However, most of the information coming out points towards higher operator efficiency, greater situational awareness, and decreased response times to critical events or alarms.
As with all things, defining core requirements and desired outcomes will ensure the smoothest implementation of high performance graphics. Simply moving 100% towards high performance graphics is not ideal, but refusing to incorporate the standards shouldn’t be an option either. There are situations where operator performance can be improved, as well as situations where traditional HMI layouts are needed.
Implementing user-based security and access will allow the desired screen motifs to be presented to the right groups. We have seen clients have high performance graphics for operators, but when maintenance personnel are logged in a more traditional screen layout is shown with information relevant to their role.
Having clear requirements and desired outcomes, prioritizing areas for improvement, and implementing role-based access will ensure the best aspects of high performance graphics are implemented alongside the benefits of more traditional systems.
CFE Media: How can wireless and cloud technologies help with data management for IIoT?
Van Der Sloot: Data continues to be consumed at an increasing rate and with the introduction of IIoT devices, the cost of the collection points have dropped significantly. The challenges begin with how data is gathered and where it will be stored for analysis. Wireless technologies allow access in previously inaccessible areas (whether due to safety or hardwire connectivity) to talk with individual or mesh networked IIoT devices. This pathway can keep non-controls data off the primary networks by routing it directly to cloud-based solutions.
Hosting data in the cloud also allows access at a global scale to data that can be compared with other sites or run individual analytics without impacting the hardware that is being relied upon to run the day-to-day site activities.
Aja: Wireless mesh network technologies are a real game changer for industrial wireless implementation. Most IT departments have shied away from wireless implementation on the automation side due to interference from typical process equipment (tanks, piping, clean rooms, etc.).
Losing connection simply from walking around is not acceptable by client standards so hard-wired connections were always preferred. Implementing a mesh network allows the addition of wireless access points wherever needed, at the same time providing seamless connection to the user across access points with no interruption. This greatly increases mobility options as well as wireless enabled data producing device options. The technology will continue to improve, and hard-wired connections will become necessary only for connecting core infrastructure, such as servers, OPC collectors, etc.
Cloud technologies have evolved greatly, and the biggest opportunity for our clients is in the hybrid cloud arena. A hybrid cloud is having a local virtualized infrastructure that works in conjunction with an offsite cloud provider for data storage. This allows clients to have the benefits of having a self-managed high availability private cloud, and the versatility and power of remote services in one infrastructure.
Most practical uses of this setup involve hosting all SCADA, historian, and automation software in a virtual environment and using a remote cloud service for historian data storage facilitating complex data analysis. This design ensures the most critical plant systems are in a controlled and easily accessible area, while simultaneously having access to the horsepower a cloud service can provide for multivariate analysis.
CFE Media: Please provide advice based on system integration experiences, applying automation, controls, and instrumentation. What did you learn?
Aja: One thing we learn project after project is the benefit of deploying the supervisory control and data acquisition (SCADA) layer on thin clients. Decoupling the hardware layer from the server infrastructure greatly increases the longevity of a system, and makes future migrations even easier. In a 10-year span, you might see five generations of HMIs from the same vendor. This can be a huge problem in a controlled environment and leads clients to stockpile hundreds of thousands of dollars of spare parts to avoid continuous migrations.
Moving physical custom HMIs into a thin-client-based deployment will soon become a requirement once the benefits are realized by the majority of the industry. Physical custom HMIs may not allow domain-based authentication, leaving shared passwords for entire user groups, which is a major security and audit trail concern. Thin-client deployments allow companies better insight into operator actions and higher amounts of security with authentication against an existing Microsoft Windows domain.
Most clients are intimidated by the thought of implementing thin clients, but by carefully evaluating potential risks, such as network reliability prior to implementation, the transition can be smooth and successful.
We are excited to see more clients requesting thin clients and confident the adoption rate will increase significantly in the near future. Once clients experience the benefits of virtualizing the server infrastructure and using thin client HMIs they never want to go back.
Mark T. Hoske is content manager, Control Engineering, CFE Media, firstname.lastname@example.org.
Use color, animations, graphs, alarms, and standards carefully when designing HMIs.
Wireless helps with data collection.
Thin-client architectures and virtualization save resources.
An article in this issue includes HMI advice from subscribers responding to Control Engineering research.
See related articles linked below.