How does everybody like to indicate on HMI the state of digital/boolean IO? Conventions on color, shape, text, or a combination that is intuitive at a glance?

Basically I'm just trying to come up with a standard for our own uses, to make our HMIs just a little more high-performance.

Colors such as red/green can be good, but need to be combined with other elements such as text or shape for the colorblind. Text would be good, but some operators are illiterate or foreign and may not understand TRUE/FALSE. ON/OFF could work, or 1/0

I'll also want to visually distinguish between inputs and outputs, each with their true/false states, somehow.

Would anyone with experience out there like to share what they like to use? Or are there some examples of bad HMI practices that really grind your gears??

 

I'm in the same boat unfortunately. Our plant typically uses green for on or input high, red for off or input low, and yellow for unknown (valve switches not showing open or closed). We use visual aids such as a pump animation while running, a light switch or two position rotary for on/off. Some of our systems have I/O screens showing the name of each point and a red/green indication, but that would do little for your situation. Graphic displays with a high contrast in colors might help with the colorblind, as they can typically see in shades of gray. You could also have a key at each screen showing what each color means so the colorblind can distinguish the shades. It's difficult dealing with such diversity in the workplace, but I'm sure if you think a little outside the box, you will be fine.

 

Dark Gray for OFF, any bright color for ON. Even color blind can see some colors. White for ON offers the most contrast and quickest recognition.

I find that two position rotary switches bunched up on a screen just look like confusing hash marks.

Labels are important, whether they are text or graphic.

http://www.iprocessmart.com/techsmart/lightcodes.htm

 

ISA a a lot of standards in place after BP blew up the Texas City refinery. And a lot about alarm management too.

 

Dear baberb, there is a very good book on high performance hmi design in the following topic:

http://control.com/thread/1414194995

In my humble opinion it is by far the best resource on HMI I've ever stumbled upon on.

If you are not in the final phases of your job, you can buy this book on amazon. If you are in the rush, I will be home soon (near the book) so I can give you some info. In that case contact me via email directly: [email protected]

I'm very interested in HMI topics. If anyone wants to share knowledge, I'm always open for discussion.

Make many high performance HMIs and thus plants safer
Many greetings!

I.H.