Welcome back, in our previous video,
we discussed the state of most current HMIs, their drawbacks, and design flaws.
We then covered why a “High-Performance HMI”
is becoming the standard for processes around the world,
and some basic concepts for developing a High-Performance HMI.
In this video, we are going to dive a little deeper
and discuss the Fundamentals of High-Performance HMI Design,
High-Performance HMI Standards, along with best practices.
One very important fundamental of HMI design
is the intended user of the HMI.
There is a common misperception that an HMI
should be designed to accommodate several different users,
including supervisors, engineers,
maintenance personnel, and finally, the operators.
This is simply not true.
An HMI is meant to be designed around the needs and the workflow of an operator.
Other personnel will have an interest in the information displayed on an HMI,
but those interests are not common,
and usually come into play when the plant is in an abnormal situation.
An HMI designed around the requirements of the operators
will give them the ability to quickly point out any abnormalities
or devices that need to be diagnosed,
without an engineer or maintenance person fumbling around through screens
looking for the problem.
This is why it is crucial for operator workshops
in the development phase of the HMI.
They can provide much needed input to you,
the controls engineer when designing a High-Performance HMI.
The fundamental part of the workshop process
is developing the HMI Philosophy Document and Style Guide.
To put it simply,
the HMI Philosophy Document will lay the groundwork for engineers and owners
to design the HMI for the process that they have been tasked to build.
It is meant to provide guidance in situations
where there are multiple control systems in a single site
to retain continuity across the various control systems.
In a greenfield project,
the HMI Philosophy Document will be relatively easy to develop
as there is not an existing HMI that operators have become used to working with.
This will not necessarily be the case in an application
where an existing HMI will be overhauled.
You will probably encounter a lot of resistance,
so this is where your wisdom
and thorough knowledge of what a High-Performance HMI is,
will be an essential item in your toolbox.
This means getting the buy-in from all stakeholders to make your project a success.
Without the support of these stakeholders,
your project may be doomed before you even start.
Once you have your HMI Philosophy Document,
it is time to develop the HMI Style Guide.
The style guide is a much more detailed document that is based on the framework
from the Philosophy Guide.
This document is where every aspect of the proposed HMI is covered.
You will get down the granular detail of the screen layout,
the color of backgrounds,
line types and thickness, text size and font,
and ISA objects for pumps, valves, and tanks.
It will also cover how trends are to be displayed
and how the navigation from one screen to another will be handled.
The style guide is specific to a project
and its specific control system and hardware configuration.
By having all of this information now,
you will know that the project you develop
will maximize the control system capabilities
and still work within the constraints of its limitations.
Again, this hard work upfront will make your project easier
and lead to a much better chance of success and of course, profits.
When you develop your HMI Style Guide,
it will become your roadmap to success.
A good HMI Style Guide will be a living document
while it is in development.
This means that a management of change process
should be a part of developing the Style Guide.
When a section is updated,
there should be quality control and approval process in place.
On final approval,
the HMI Style Guide is your blueprint to building your High-Performance HMI,
giving clear instruction to the development of your High-Performance HMI project.
A Style Guide will document the screen objects
that you will use when creating your displays.
The objects along with their source code
will become the control system specific object library for the project.
These objects are then automatically standardized
and will each have specific functions in the control system.
When developing the object library,
the object should not be individually modified
during the development of individual displays.
Instead, objects are global and are available for use across all displays
for a standardized method of displaying information from field devices.
Your HMI Object Library or HMI Template Suite
will become the predefined repository of source code
such as add on instructions, display objects and faceplates
that will enable you to quickly develop the project using tested strategies,
high functionality, and known performance.
Objects will be built with the design standards set forth in your HMI Style guide,
along with consideration given to “ISA101 High-Performance HMI” standards.
The object library will allow you to create a control system
using a drag and drop environment
in order to quickly create a control function.
For example, an analog input object
will have predefined scaling, alarms and engineering units,
among many other features.
Then the corresponding faceplate will give the operator
an intuitive and information-driven visibility and control.
By using this modular design,
you are able to access a large number of small components
that will make up an overall control system.
This method of development leads to a reduced chance for error,
reduction in development time and cost,
and increased profitability.
Remember, offsite backups of your library are essential.
There have been many horror stories of an object library being lost
because it was stored on a single laptop computer hard drive.
We hope you enjoyed the second part of series on High-Performance HMI.
This series is meant to give you the foundation of knowledge
to begin creating High-Performance HMI projects.
Want to learn PLC programming in an easy to understand format
and take your career to the next level?
Head on over to realpars.com