Indicating Lights

The fact that you are asking the question indicates to me that the color of the light may not be as important as the legend under the light that says, "trip , on , off etc ".

Just a thought.

yikes!

I don't know of anything that gives the color of the lamp as a standard... I may be wrong, as it isn't my field, but when I design panels, I choose whatever I feel for the lamps (usually driven by cost/availability). However, in General, colors do have emaning... For example:

Green : All good

Yellow : Caution

Red : Danger

I typically try to adhere to that general color scheme.

Different industries/operations adhere to different standards. I have personally seen red, green, amber, and blue indicate different status at different plants. I do not recall ever seeing an indicator color legend on a control panel, only as part of plant specific training. Same gos for wailing vs steady siren evacuate, or take cover? Where am I?

Well.. it seems Ive been designing all of my HMI panels backwards as far as the color scheme goes... harrumph!

At least it used to make sense to me.

Well... actually... It makes perfect sense, as long as you don't think about it!

It does makes sense...but I always looked at it like we describe stuff in the gov't supply system:

Hammer, claw, 1 each

bearing, pump, emacerator, centrifugal, 1 each

I don't know why we do the things we do...

Not color, but odor. Once you smell something burning, that means it's BAD!

You mean that BROWN smell that usually tells you that something horrid has gone wrong.

NFPA79

or have a look at http://raywinstead.com/nintendods.shtml

That's the standard I have seen in gov't plants for over 20 years.

Dear samad ,

I have been working in saudi arabia , Present job in jeddah , My name is abdul malik i have seen in your post many times and i found i gain good knowledge to your comments i have small clarification i just request you to please i would like to know what is Utilisation factor where we will this factor , what is ks and ku where to appply this factor in which formulaes .

Thanks & Allah Hafiz

Abdul Malik

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I have seen official standards that follow msamad's explanation, especially in the electrical sense that red = energized = potentially dangerous.

On the other hand, from a process point of view, I have also seen informal standards in which green = running (energized) and red = stopped. (Like traffic lights.)

Hence a possible source of confusion. Why are emergency stops usually red, if pressing them deenergizes things to condition green?

Hi Tornado, Msamads is correct. I do understand it is a bit reverse thinking, Red- Danger, Green-Safe.

Now Tornado let us think about this in another way: You are driving along the road and you come up to an intersection, the red light is on; that means danger, do not proceed. but if it was green it means is i safe to go through the intersection. Amber means to take precaution.

Large main switches have Red indication for Power On(danger) and Green for Power Off(safe).

But you are also right, we use a green light for running condition and a red light for stationery condition.

I suppose this goes back a long way, if the green light is on don't touch becuse it is running. and the same for the red light.

I don't have all the answers, but someone out there will be able to answer this one

Best Regards

Joe

I think lyn gave the best answer first: the lights need to be clearly labeled. Color can be confusing, so a tag is better.

NFPA 79 Section 79-28 says Green for on, Red for off, yellow for caution.

HA! so I have been doing this right all along then?

NFPA = National Fluid Power Association... I work in the Fluid Power Industry, but only made the assumption that green was go and red was stop.

Thanks for the concrete information, I can sleep a night now.

Not so fast! It's the:

I would not discount anything that msamad says. I believe that he speaks with a considerable amount of knowledge and experience. Maybe it depends on the industry.

But, it is covered by the N Fire PA code.

Dang...

OK... Alright... I'll re-insert it then.

_{<Quietly shuffles off to the corner and inserts foot into mouth.>}

_{Grumble grumble grumble...}

On newer medium voltage (5KV and above) switchgear at the bucket(s), I have seen Red=Switch Closed, Green=Switch Open, Yellow=Switch Tripped.

In the same plant one electrical room away on a lo-volt (480 Volt) MCC at the bucket(s), I have seen Green=Start, Red=Stop.

On 5-7+ year old and older MV gear I have seen Green=Switch Closed, Red=Switch Open, White=Switch Tripped.

My understanding through my gear vendor was that the recent MV gear color scheme is the result of changed manufacturing standards brought about by changes in the NFPA, OSHA, and the NEC.

Still kind of confusing between new/old MV, LV Gear, MCC's. Combo-starters, operator PB stations, ect.

And the plot thickens.

Maybe this is just like driving a car. We drive on the right side of the road here in America and they drive on the wrong side of the road in Europe.

_{Runs away to hide in corner.}

I think I'm done with coolyaar. He seems to be studying for a test, or taking a class and using us as his reference library.

Adios sucker.

One thing I think must be made clear, the original question (regardless of the motive) was regarding PILOT LIGHTS. Some of the responses seem to be referencing PUSH BUTTONS. They are not the same thing. Buttons are for Actions, Lights are for Status.

A Green Push Button means Start / On / Energize, whereas a Green Pilot Light means Off / Safe / De-energized.

Red PB = Stop / Off / Make Safe, Red PL means On / Hot / Dangerous state.

Where it gets really muddy is when you use illuminated push buttons where the function is combined!

Re: Nameplates. In a perfect world, I would agree. But more and more I see problems with this. I recently had a small project at a concrete roofing tile production facility where this came up. I suggested the nameplate route, the response from the owner? "Most of the operators are not going to be ablle to know what they say." I responded "We can show them in English and Spanish (thinking that was the issue, I am in California after all). His counter?

"No, they are illiterate in all languages!"

They decided to go with the "Traffic Light" scheme dispite my objections because he felt he could get that message across. "Green means Go / Going", "Red means Stop / Stopped". << shudder >>

I moved from the chemical industry to the iron industry. Compete about face as far as red and green was concerned. It confused the hell out of me for quite some time! Caused a few arguments as well with me telling the plant operator to start up, only to be told it is running!

I forget whose tagline says, "That's what I like about standards; there are so many to choose from."

My plant has both schemes and then some, but I have learned pretty easily to digest either mind set, after some initial disorientaton.

(All of these red lights can't mean that all of my blast freezer fans went out on overload...oh, wait a minute; that means they are all running. Whew!)

Adding more confusion ....according to this red pilot lamp eg :(protection device stopped the machine ex.overload) ......

G'day Mandi,

That looks like a top poster to have around when settling arguments about what colour means what and I would really like to have a copy of it. Unfortunately the CR4 image processor has downgraded the resolution to the point that the text is illegible.

There are a couple of ways round this:

• Post the URL for the original image so that we can follow it and get access to the original image.
• Insert the URL of the original image in the top text box of the "Add/Edit Image" dialog box as shown below (where it says in red Insert URL here). This doesn't reformat the image and you get the full original image in its original size and glory.

Please find the URL http://www.iprocessmart.com/techsmart/lightcodes.htm,,

Thanks.