The High Performance HMI Handbook and You – Part 1
Starting with ISA-101 a standard was set out to create a more effective HMI design philosophy to be implemented. This style of design known as the High Performance HMI has shown not only to increase the reaction time of operators by elimination of superfluous data and highlighting what is important, but in general improves safety and efficiency.
Bill Hollifield was part of the team that set up this standard but has also written a very in-depth book on the subject matter known as The High Performance HMI Handbook published in 2008.
Here at Corso we all have found inspiration from this book and use it as a basis for our design approach. The book not only acts as an excellent guide for HMI redesign and implementation of these techniques but also how to go about setting up a philosophy and style guide standard for your company to adhere to. It also isn’t a slog of a read and is littered with wonderful quotes that are relevant and humorous.
We use these principals to help guide us as we start major implementations.
Side note: One of the main things we love about the Ignition platform is not only its ease in creating High Performance HMI style graphics but they also encourage it and have a wonderful section of their manual dedicated. You can check that out here.
The book is split into four fundamental sections along with an appendices of wonderful references and guides to further your understanding. To save you from a wall of text I will give you an overview of each section in separate posts.
- The History and Current Status of the Industrial HMI
- Fundamentals of HMI Design and Best Practices
- Design and Implementation of a High Performance HMI
- Control Rooms, Abnormal Situation Management, and the Future of the Industrial HMI
The History and Current Status of the Industrial HMI
This sections starts it all off by providing why the book was written, the intended audience, and a word of warning on the inevitable debate about design. From our experience there is always a balance between best practices and what the customer wants. You can provide technical data, results from human performance studies, and all the reasons why you should design this way but at the end of the day customer satisfaction is key. We always work to find that happy medium between both so we know we are not only providing a better experience for the operators but also sticking to the customers wants and demands.
Next they go into the history of HMI design from the old electrical control panels, DCS systems, and early computer graphics. For those of us who entered the industry after 2006 it is a good insight into what problems early engineers faced and how they adapted to the changing technology. They also address one of the common persistent issues of HMI design: the P&ID display. Depending on the design needs most P&ID type displays are cluttered and do little to provide the information necessary to operation without convoluting it with symbols that often the operator has no idea of their meaning. One place we do find these effective is in creating maintenance/engineering specific views for debugging purposes.
From there they lead into the over cluttered graphical interfaces that began developing and provide a justification for the change in HMI design. Inspiration came from early avionics panels of small planes. These displays often had a limited amount of items displayed focusing on only the most important aspects for pilot to see.
You would have generally low-contrast imagery with minimal color usage which focused only on important alerts and notifications so that pilot could react quickly and properly to any impending issue. This concept applies easily into HMI design by limiting the amount of clutter and using colors only to represent alarms so we are able to create more effective displays.
Every project always has the argument of whether to use green and red to signify the operational state of a machine when in best practice red should be used only for alarm notifications so that the eye can catch it quickly and the operator can respond effectively. Instead of “Operating by Alarm”, which is an ineffective manner, the idea is set out to great graphics that allow operators to more accurately determine when something is going out of the desired limits so they can act to prevent an alarm instead of reacting to it.
Lastly they finish the first section on the HMI best practices. The idea of the High Performance HMI is that it enables an operator to safely and effectively monitor and manage their process by implementing a system of best practices. The focus of this should be increasing situational awareness to improve accuracy and timing of response. One of the the ways this is done is by creating four distinct levels of displays:
- Level 1 – Process Area Overview – The main overview display that should focus on important items and display alarms and alerts in a cogent and easily determinable manner.
- Level 2 – Process Unit Control – Subprocess, variables, and control manipulation for reaction.
- Level 3 – Process Unit Detail – Further detailed examination. Individual machine controls, specific alarm displays, and information.
- Level 4 – Process Unit Support and Diagnostic Display – Troubleshooting information, possibly P&ID, and anything else that its not important for operation but necessary for maintenance and management.
This leads into redesign focusing on only the most necessary and important information to the operator. The fundamental philosophy that if you don’t need to see it then get it off the screen. Unnecessary blinking lights, colors without purpose, and other things that provide a distraction instead of information need to be removed. When redesigning the focus should be low-contrast, plain flat imagery. No overabundance of 3D style graphics and animation. Displaying only the important process values and using color in a limited way to highlight abnormalities and alarm conditions. Simple layouts that follow the process logically so the operator can easily take the information from their screen and react to it in their process environment. Creating a hierarchical structure to expose more detail as necessary. Lastly, minimizing the amount of keystrokes or actions necessary to perform a task.
7 Steps to creating a High Performance HMI
- Adopt a High Performance HMI Philosophy and Style Guide
- Assess and benchmark existing graphics against the the HMI Philosophy
- Determine specific performance and goal objectives for the control of the process, for all modes of operation
- Perform task analysis to determine the control manipulations needed to achieve the performance goal and objectives
- Design and build high performance graphics, using the design principles in the new HMI Philosophy and elements from the Style Guide, to address the identified tasks
- Install, commission, and provide training on the new HMI
- Control, maintain, and periodically reassess the HMI performance
In the next post we will look more into the fundamentals of HMI design and best practices. To finish a quote from one of my favorite authors that can be found in the book:
“Humans beings, who are almost unique in having the ability to learn from the experience of others, are also remarkable for their apparent disinclination to do so.” – Douglas Adams (1952-2001)
For a brief overview of HMI types and design check out our article here: Your Human Machine Interface (HMI) Guide.