I have been involved for over 25 years in HMI DCS and PLC/PAC. I have worked on old and new from ABB Bailey, Fisher Provox, Honeywell Plantscape and all the Rockwell RS View/FT View contrologix etc...etc... so I have seen and worked on quite a few HMI designs. I have seen a confusing trend that compels me to ask a question. I have read a lot of documents pertaining to "Abnormal Situation Management" that have been written by people much more educated than me that condemn the use of animation, color, and 3d detail from HMI design in favour for a bland, sometimes shades of gray simplistic rendition of a process.

I personally see nothing wrong with an animated "flickering flame" to indicated a burner on condition of a boiler or larger industrial dryer.

However from what I have read, I have it all wrong.

So lets take a look at the most successful HMI design of all time, the largest install base, the most widely used, the highest commercial purpose, as a sample of how it should be done.....

Video lottery machines (Slot Machines)

Very colorful,very animated,and crucially very successful even for new users. But still very, very wrong

Do you think someone should tell Las Vegas?

 

I also have been doing it for a while and have built a few thousand HMI screens over the years and although I don't have a PHD in psychology etc. do not like nor think that the new as I call them "morgue blue on grey" screens are the way to go.

My operators are my customers and the feedback I get from them is they like my screens.....standard green when running, grey when off, yellow warnings and red faults. I make logs brown, water blue, machines a slightly duller color of the actual color they are etc. now most of my operators had total crap with little info so you could argue they would be happy with anything, but they compliment my screens all the time.

I think watching these new wave screens are like watching a black and white movie, puts the operator to sleep rather than keeping him/her involved in the process. Maybe it works for some processes, but I am involved in processes that are completely run via the computer, not much field interaction so it is a giant video game and they need to be kept focused. Let them know when abnormal things arise but give them a ton of info and drill down screens.

Dave Ferguson
Control Systems Engineer

Sent from my iPad

 

On the other side of the coin, another extremely successful HMI is the ubiquitous automated teller (money machine).  It has an extremely simple user interface, I don't know anyone who cannot figure out how to use one...
 Bill

 

I have done thousands of screens as well. Over time I have come to think simpler is better. I also think that making my screens look more like what the operator is used to seeing is probably more important.

 

The problem with gratuitous moving, flickering, flashing etc is that it can interfere with the natural human instinct to react to small movements or changes in our peripheral vision. I've always considered that a good display is a dead display, with nothing happening - then when things start to change there is a much greater chance that they will be spotted even if the operator is not directly looking at that display.

 

The slot machine analogy is flawed. An HMI and a slot machine have very different jobs.

A slot machine wants to keep the seat in front filled and the lever getting pulled at max frequency in spite of attention span, hunger, fatigue, bladder level, blood alcohol level, etc., so it HAS to be entertaining and engaging.

An HMI needs to make information and control functionality available to the user in a convenient, hopefully intuitive way, while minimizing confusion and information overload. It doesn't necessarily HURT anything if it's entertaining, but the objective is to help him do the job he was already there doing, maximizing safety for him, other humans, the equipment, and optimizing productivity and waste. In other words, it's trying to help him WITHOUT getting in his way. In fact, the more he can learn/do in the SHORTEST time in front of the screen, probably the better.

So in short, an HMI HELPS with some task, whereas a slot machine IS the task.

Now, in this post I'm not trying to delve too deeply into my screen design philosophy, but rather trying to say that if you think slot machines' ubiquity and success proves they're a good model for process and manufacturing HMI's, I think your logic is flawed.

 

I think somewhere in the middle the truth lies. I agree with Bruce that movement or change should draw the eye, and that if nothing needs intervention nothing should be happening on the screen. On the other hand, animations can be quite helpful. For example, changing the display to graphically indicate the current step in a sequence of a process can be quite helpful, particularly when the process is difficult to observe.

Recently I've started to agree with the idea that "Thou shalt not have red anywhere on the screen if there are no faults." But I also have a big STOP button at the top right of every screen, and right now we make it red, because that's the color a stop button should be. I haven't come up with a way to deal with that conflict.

While we're on the subject of red, one thing no one has brought up is color blindness. Red / green color blindness is apparently more common than you might think. The Wikipedia article on color blindness includes a small section on "Design implications of color blindness," which isn't so much helpful as it is a reminder that we need to think about it. I haven't quite come up with a good solution for that problem, but what I've started to do is use green = good, and for bad a flashing yellow / red with a big black X over the indicator. This doesn't solve the problem of my big red STOP button on the top right and my big green START on the top left, but hopefully the spacing and the large text help distinguish them.

Don't forget that screens have to look good for marketing purposes. A bean counter, or even an engineer who's now in project management or purchasing, is not going to immediately think, "Ah, that screen is kinda boring looking in order to deal with red/green color blindness, and has good usability." They're going to think "Meh." Then they'll see an animated 3D screen and think, "Oooo, pretty!" So like I started off with, you have to look good without going to far.

Of course, what part of our jobs ISN'T about trade-offs?

-James Ingraham
Sage Automation, Inc.

 

I spent the first couple of years on the ISA sp 101 committee and then life and a job shuffle forced me to the sidelines, although I am still a non voting member of the committee, I still watch and try to keep up with where it is at. There were members that thought we would spend a few months and be done and here over 5 years later, they are still hashing it all out.

It is a very hard and somewhat frustrating thing to try to appease all of these varying factors. Just look at issues like color blindness, color usage, text and the. Throw in cultural items of a worldwide standard. If we ever thought we were getting somewhere, all we had to do was mention the red green thing and all the power guys were adamant and all the others were also for their side.

As I said I still prefer the 4 primary colors red, yellow, green and grey and showing sequencer steps and pipe flow etc but I tone it down so that an all green screen is good and yet they can quickly tell when something is running or idle and yellow and red only show up if something is Ina bad state or has failed.

I think that the greyed out screen with words like on or running are not enough for the human mind to decipher. But again as I found out being part of the standards committee, there is no universal agreement on this one.

I also am a hater of flashy 3D graphics and have told more than one bean counter or manager who thought they were cool, that they were idiots (sorry not very PC in my old timer state). I spend ALL of my time staying up on these topics and have no time for amateurs any more .

You can standardize some things but you will never universally standardize across the world something like this IMHO.

Dave Ferguson
Control Systems Engineer

Sent from my iPhone

 

The way I've always done things is with text messages for fault conditions. There is a clear audible or visual alert (buzzer, light stack, popup window, etc) followed by the presence of a message that the operator is required to acknowledge (And this acknowledge goes back to the machine logic). Sometimes you can tell the operator what might have happened to lead you to this particular fault given the path of the logic that led you there.

Besides internationalization and illiteracy, is there a reason to draw pictures and animations for HMI screens as opposed to the text faults? Is it more for batch and continuous processing applications rather than assembly/packaging/CNC machines?

KEJR

 

Are colorful and very animated graphics wrong? The answer is "it depends." It depends on your objective for those graphics. If you own a casino in Las Vegas, then it is absolutely correct to be colorful and animated-- the objective of those graphics is 100% marketing.

On the other hand, if you are trying to control a process, you are better off with toned down colors (except for abnormal situations) and limited use of animation (except for abnormal situations--such as alarms blinking). The intent of the graphics is 100% process control.

When you play slot machines, you have no control over the outcome once you press the button or pull the lever. Therefore, the colors and animation have no influence in your luck. This is a completely different story for process control. The operator must realize there is a problem, investigate, take appropriate actions and monitor. The graphics should be able to assist in finding the problem-- by reserving bright saturated colors for abnormal situation indication, you help the operators find those problems as they jump out of the screen. However, if you use bright colors for everything on your screens, finding an abnormal situation is like playing the "Find Waldo" game.

There is a misconception in industry that High Performance HMIs are grey graphics. This is absolutely wrong-- there are many other components to high performance graphics besides appropriate color usage. Many companies are turning their graphics greyscale without applying the other components, hence not getting the "bang-for-your-buck." I invite you to attend a 45 minute webinar at "pas. com" where the different components for high performance graphics are discussed.

 

I thank all of you who have read and even replied to this post. I agree with much of what has been discussed about HMI design and the importance of finding the “happy medium” between too much animation /color and too little in detail.

I disagree with the hasty generalization of all slot machines are “pull the level” only. I have just returned from Vegas with some new insights to share. I watched and studied the latest casino machines that, in my humble opinion, deserve another HMI design consideration.

I watched the “operator” make custom preference changes to his color theme and system volume. Several various “games” can be played on the same machine so several “navigation” methods are presented. Most interesting was the button called “Game Stats”. It produced a series of “trends” and bar graphs showing the” historical statistics” not unlike any HMI historian I have ever seen. With “Process Tags” such as “spins per hour” and “accumulative spins” since last payout and at various tiered pay levels I was intrigued to study further but was prohibited from taking any photographs. Instead I watched the ‘operator” using the “HMI” to continuously adjust betting odds and tailor an edge in reaction to the video “ craps” based on historical trends and intuition. This is not simply pulling the lever anymore. The success of this HMI has to be based on “engagement”.

This “operators” vested interest in winning ensures he/she will do whatever they think will help to succeed.

I has seen both ends of the spectrum from way too much color and animation to way too simple. By simple I mean all types of different machinery shown in gray with the same rectangular shape and size on the screen with no relevance at all to the shapes and sizes in real world. Somewhere in the middle lies the balance and even then it is particular to the situation. Take light gray back grounds for example, in the asm handbook it details the correct amount of ambient light (in lumens) for a control room. It does not take into account the chance the same room might have a window to outside that allows the presence and absence of natural light daily. Enforce the control room lights on 24/7? Just turn on your vehicle interior lights while driving at night and tell me how long you go before wanting to turn them off.

Even the power station that helps powers this country does not employ gray scale backgrounds as seen in this you tube video from an automobile advertisement comparing itself to the Hoover dam. In the short video we see a glimpse of the operator HMI worth a second look.

Perhaps the most unsuccessful location for the next ASM symposium would be Las Vegas. Everyone would be making the decision to look at bland or boring shapeless graphics or say to heck with it and see you at the casino.