Are multicolor panel indicator lamps useful or confusing?

[e100]

I'm assuming that the user has normal color vision.
The context is a piece of test gear on a bench and the indicator lamp has a RGB LED.

For example, green = on/running, red = fault of some kind, blue = ready.

The only place I've seen multicolor indicators is on charging cables where it shows the difference between a charging or fully charged state.

[coppercone2]

I don't see the point unless there is like no room. I don't think it belongs in serious equipment because a fault is serious. Plus with multiple lights you can use tape on the ones that dont matter

sit infront of some crap all day in a lab and it can get really annoying to look at some green marketing light

IMO its the same thing as multifunction keys, regular users find them annoying, new users get confused with menu navigation. and no one is going to renember what the colors are in 2 months, and you will be unable to read the legend after its decorated with corporate stickers.

but they usually don't cover up a LED. But a cal sticker is more important then the front panel display. don't matter if those numbers are correct, so long it passes inspection. 1volt? 11 volts? -1 volts? whatever dude, its calibrated!


ahahaha the best one would be a RGB led indicator that is menu reprogrammable. no one would know what its doing ever

and you should anticipate color blindness  as a designer

[MarkT]

There's actually a machinery standard for this, red = hazard, green = safe, blue = operator attention required, IIRC.  Not so relevant for test equipment though.

Which is pretty broken when you consider the commonest colour-blindness is red-green!

Use a steady light for power, flashing for abnormal / attention required perhaps - only need one colour and hard to misinterpret.  Many items use a flash code, where the count of flashes indicates the reason, for instance 3 flashes, pause, 3 flashes, pause, ...

[nctnico]

Probably the order of the lamps is standarised as well. Like a traffic light.

[Gyro]

I find it useful on my insulation tester. Red = HT on (danger), Amber = tripped (caution). I can see it without having to focus directly on the panel. There's no green though - it's never that safe!

[Siwastaja]

Which is pretty broken when you consider the commonest colour-blindness is red-green!

You can compensate by picking the hues wisely. Which is made easier now, as modern high-intensity green LEDs have a cyanish tint, deviating from "perfect" green by maybe 10nm towards blue, which makes it much easier to distinguish for red-green color blind than the old school dim green LED which is pretty yellowish (more than grass green) even for us non-color blind.

Of course, use ordering and labeling whenever the status actually matters. Color blindness is surprisingly common. For non-critical stuff, most color blind people would be fine if you adjust the tint. With RGB LEDs, the biggest mistake to avoid is mixing any blue into red. Color blind people use blue component as a hint that "this is probably green".

[CaptDon]

With the R/G bi-color LED's I prefer steady red to indicate OFF, flashing red to indicate ATTENTION NEEDED, flashing green to indicate READY, and steady green to indicate OPERATING. Red can become ambiguous either indicating OFF or FAIL, case in point, a motor contactor which has tripped. Often the auxilliary contact lights the same red indicator as the off condition since off is often the dropped out condition of the contactor. Steady red seems to imply 'off, no attention needed' while flashing red seems to indicate 'Look here, something is amiss'. Enter the R/G/B/ tri color LED and it's anybody's guess what the indication means. I have the nice 800 series Allen Bradley panel hardware in the wheelhouse and most indicators are also a switch including a press to test lamp function. My air compressor has a green to indicate energized but also has an amber 'compressor is actually running' indicator which lets me know the air pressure is low and building back up. My macerator pumps only have an amber which when lit tells me the pump is actually pumping. I suppose it all comes down to being familiar with your operating position and duties. What one person finds distracting may actually be of comfort to a different person.

[exmadscientist]

And do consider that for real safety-critical lamps, blinking on-off may be a real problem. A few years back I worked on a hi-pot tester that blinked an LED to indicate HIGH VOLTAGE ON (as required in the Standard!). I of course worked with these units a lot during the design process. More than once, I glanced at the LED while I was doing something... saw it OFF... and thought the HV was off. It wasn't. I just caught the OFF phase of the LED. More than once.

Of course, I was fine, as I wasn't dumb enough to use that as my only safety mechanism... but still. Blinking (like everything else!) must be used with great care when real safety is involved.

(I suggested instead that we blink the LED bright-dim instead of off-on, so it would always be at least a little bit illuminated when things were dangerous. We were early enough in the design that this would have been no trouble to do. The amount of pushback I got on this was incredible. No one disliked the idea... it was just "too hard" or "not relevant to users" (how many times have I made this mistake this month? Does that count for nothing?) or "not what the previous unit did" (no ****, we were making a new design for a reason...) or my favorite "not what the standard calls for" (did you read the standard? No? Well, I did! It doesn't care!). Product design, what can you do!)

[coppercone2]

And do consider that for real safety-critical lamps, blinking on-off may be a real problem. A few years back I worked on a hi-pot tester that blinked an LED to indicate HIGH VOLTAGE ON (as required in the Standard!). I of course worked with these units a lot during the design process. More than once, I glanced at the LED while I was doing something... saw it OFF... and thought the HV was off. It wasn't. I just caught the OFF phase of the LED. More than once.

Of course, I was fine, as I wasn't dumb enough to use that as my only safety mechanism... but still. Blinking (like everything else!) must be used with great care when real safety is involved.

(I suggested instead that we blink the LED bright-dim instead of off-on, so it would always be at least a little bit illuminated when things were dangerous. We were early enough in the design that this would have been no trouble to do. The amount of pushback I got on this was incredible. No one disliked the idea... it was just "too hard" or "not relevant to users" (how many times have I made this mistake this month? Does that count for nothing?) or "not what the previous unit did" (no ****, we were making a new design for a reason...) or my favorite "not what the standard calls for" (did you read the standard? No? Well, I did! It doesn't care!). Product design, what can you do!)

im just gonna sit at the table and make money right? this was supposed to be a promotion you never said anything about thinking!! just keep saying no to those guys usually they stop asking...

when that boss has the preordained plan of exactly how many things he can consider per quarter. he even wrote down what in his organizer so he can memorize the question and outcome before they happen. Ever feel like during those brain storming sessions they already know exactly what they will say they considered in the subsequent meeting with their higher up and that its on autopilot for at least a year? its like sheet music. did anyone even say that at the meeting? were the meeting notes fabricated last year before the meeting?



Speaking of something relevant, you ever notice how blinkys sometimes make you think their on when their off ? like you see the blink in the corner of your eye when its definately off? it has psychological effects.. I don't like em. Hakko did this. plays tricks on your mind.

so medium-bright is way better then on-off. it needs to glow a little bit. I must have seen this soldering iron 'not blink' at least 100 times in the last 15 years.

[Siwastaja]

And do consider that for real safety-critical lamps, blinking on-off may be a real problem. A few years back I worked on a hi-pot tester that blinked an LED to indicate HIGH VOLTAGE ON (as required in the Standard!). I of course worked with these units a lot during the design process. More than once, I glanced at the LED while I was doing something... saw it OFF... and thought the HV was off. It wasn't. I just caught the OFF phase of the LED. More than once.

The solution is obvious: faster blink rate. Fast blinking tends to indicate danger, or that something is "wrong", and you register the blinking even with a quick glance. Perfect to indicate dangerous high voltage being present.

Slow blinking usually indicates "standby" or similar. Slow blinking makes people relaxed, fast blinking gains attention.

The problem with bright/dim blink is that under strong ambient light, you still miss the dim. Or, you just think the dim glow is some sort of an artifact (light leakage, leakage current, just a reflection...) And if you increase the "dim" level, then you risk reliably detecting the blinking (changes between bright/dim). Classic solution is two alternatively blinking red alarm lights, and a third white or green OK light.

[2N3055]

For warnings, blinking the "nervous", irregular pattern also helps.
It draws attention even in peripheral vision.

[coppercone2]

but irregular blinking can be confused for a data bus light like old computer hard drives or something

[luudee]

IMHO, I love different color indicators. Like my PSU, will have the output button Green under
normal conditions, and red when it is in overloaded. I'm not a fan of blinking lights, no matter
what condition. I usually sit in front of my equipment and can see the color change. If you really
need my attention right now, then sound a beeper !

Same with my DSO, green when running, red when stopped. Simple and clear.

I read somewhere that an average male can only distinguish between a limited amount of
colors/shades, whereas women can distinguish 100 x more than that, 

I think in moderation, and it must be functional and useful, I love color indicators. But I
would not want my instruments to look like a Christmas tree !

Cheers,
rudi

[coppercone2]

I think you learn colors if you study them, try buying some narrow spectrum lights to play with. spending time in home depot paint section also helps (paint cards)

i think women might just be willing to stand in the hardware store paint card isle for 4-5 hours a year when males do 3 minutes maximum. men also don't like to pay or interact with colored objects too much, at least wont pay extra for a exotic color, so they get no exposure

similar to training your ear for sound. takes work and time

[kevin.gibbs]

I think they can be both helpful and confusing. If the color assignment of the LEDs is the same for different nodes (e.g., red is a fault, as you indicated), diagnostics should be more accessible.

[Benta]

You see it in your car every day when starting it.
Mostly yellow/red conbinations, eg, CEL off: OK, CEL yellow: drive to workshop, CEL red: stop immediately.

Very useful in that context.