Standard Color for indicator lights
Standard Color for indicator lights
(OP)
I am looking for an available standard that provides guidance for using indicator lights.
The confusion is that in the Power Industry "Red" is traditionally used to indicate running.
In my manufacturing experience, "Green" is used for running. This is derived I believe from the old "JIC" standard that is no longer supported. Is there an industry standard that specifies or recommends a position
Thanks
William F. Moore
The confusion is that in the Power Industry "Red" is traditionally used to indicate running.
In my manufacturing experience, "Green" is used for running. This is derived I believe from the old "JIC" standard that is no longer supported. Is there an industry standard that specifies or recommends a position
Thanks
William F. Moore





RE: Standard Color for indicator lights
green - circuit breaker, switch is open
red - circuit breaker, switch is closed
for mechanical (valves):
green - valve is closed
red - valve is open
wbd
RE: Standard Color for indicator lights
OP may want to review Thread248-39408.
RE: Standard Color for indicator lights
RE: Standard Color for indicator lights
RE: Standard Color for indicator lights
RE: Standard Color for indicator lights
RE: Standard Color for indicator lights
Thank you. Now I am as confused now as when I started this quest.
As stated so eloquently it is the users choice, and I will ask them to decide.
The reason for the question is that there are three conflicting designs by vendors that are being integrated into a project. 2 Will have to change their designs to accomodate. I was hoping that there was truly a standard to apply. NFPA, I believe is quite ambiguous depending whether you are discussing Life Safety or Process Performance.
Well, Thanks again
William F. Moore
RE: Standard Color for indicator lights
For what its worth:
I by no means would say we are politically correct, but for the petroleum sub-pump industry our typical lights are:
Green -- Running
Yellow -- Stopped, but auto restart pending, timer running
Red -- Failure that will not auto restart
It would be nice if the whole world was on the same page! If you find some written standards please post them.
If you want some fun swap some lenses.
RE: Standard Color for indicator lights
RE: Standard Color for indicator lights
It'd be nice if the whole world would follow that lead.
RE: Standard Color for indicator lights
When was the last time you went through a red light (knowingly).
In my country (I suspect yours too) RED means "STOP" and GREEN means "GO". It would be a shame if we were to reverse the meaning of this symbols as you suggest, just so the pharmaceutial industry can advance themselves. Sounds selfserving to me (Just kidding).
Convention for me is; when the machine is off nothing is illuminated. If the machine is running (normal running condition) AMBER indicators maybe illuminated.
Upon a fault condition, the machine is shut down and RED indicator lights are illumated indicating the cause of the outage.
To use RED as a general indicator of operation, is a false indicator of operation.
What if you had to enter a very tightly closed room and you could only enter the room if the fresh air fan was running. Would you enter the room with a RED indicator light by the door or a GREEN light.
Regards
pennpoint
RE: Standard Color for indicator lights
Good luck getting anyone here to standardize on light colors here. Good luck getting anyone to standardize on digital cell phone standards, HDTV standards, or Mac vs. PC too while you're at it.
I agree that there's a saftey concern here, but both standards are very entrenched. Even worse, as observed by wfmoore, "NFPA, I believe is quite ambiguous depending whether you are discussing Life Safety or Process Performance." Now, THAT's entrenched.
RE: Standard Color for indicator lights
It's a thought. Personally I would go with red means pump on...breaker closed....valve open. That's what I've always seen.
RE: Standard Color for indicator lights
My experience is that red = energized = run is much more common in U.S. industrial facilities than the opposite. I believe this practice stems from the use of red to indicate a closed breaker or energized bus in electric utility systems.
If you accept that you will use red to indicate "energized", it's a little tough to decide green means running.
I believe the Navy using red for running as well, but I could be wrong on that.
The red/green traffic light analogy is really a red (green?) herring.
It's also interesting to note that building exit signs in the US can be either red --- or --- green.
You must use whatever is standard in your facility. The worst possible situation is not being consistent.
Despite whatever standards may be referenced, there is no single accepted standard in the US.
I believe even OSHA acknowledges that this is a "local custom".
RE: Standard Color for indicator lights
RE: Standard Color for indicator lights
Think about it:
Red does not mean Stop, since you may already have been stopped for some other reason. It really means "Danger: You will likely be killed or injured if you Go into (or stay in) this intersection!"
Green doesn't necessarily mean you MUST Go, it means "OK to do whatever you want to in that intersection, including stopping in the middle, smoking a cigaret etc., because it is safe for you as long as it is still Green (and the guy behind you does not have a gun)!"
Yellow of course then means "Warning, this intersection is about to become very dangerous for you!"
As far as I am concerned, this follows the vast majority of industrial color code logic.
If you do not agree with this interpretation, ask any police officer what you are expected to do if you are already in an intersection and the light goes from Yellow to Red: Do you STOP or do you get the hell out?
Quando Omni Flunkus Moritati
RE: Standard Color for indicator lights
So, maybe the color doesn't even matter anymore.
Pennpoint, how's your compliance to the new flash standard?
RE: Standard Color for indicator lights
RE: Standard Color for indicator lights
http://www.fletc.gov/pro/ftc01-A04/specs/16410.pdf
for ATS indicating light standards taken from AIA specs Section 16410 Automatic Transfer Switches:
2.1.1.10 Indicating Lights
a. A green indicating light shall supervise the normal power source and shall have a nameplate
engraved NORMAL.
b. A red indicating light shall supervise the emergency power source and shall have a nameplate
engraved EMERGENCY.
The nameplates under the lights are enhancing safety when it comes to emergency systems and in general
RE: Standard Color for indicator lights
The flashing light idea was something I heard from a couple different vendors, back in December or so. For me to call it a "standard" was perhaps misleading, sorry for any confusion. I've not seen anything documented on this.
RE: Standard Color for indicator lights
And to further muddy the colored waters, don't forget those afflicted with "color-blindness", especially the green-red kind!
Peebee, I hope it wasn't anything like the "bouncing-ball" fiasco that was used to increase traffic thru NYC's Holland-Tunnel, years ago!
RE: Standard Color for indicator lights
RE: Standard Color for indicator lights
The Port of NY/NJ Authority traffic-control guru's installed a number of strobe lights at predetermined distances the length of the tunnel. The idea was for drivers to keep abreast of the "ball of light" as it "flashed" thru the tunnel, thereby maximizing the number of cars the tunnel could accomodate.
The problem... motorists were so intent on watching the bouncing "ball of light" that their driving skills were, well, for lack of a better term, ignored. The result... a major increase in accident-rate!
RE: Standard Color for indicator lights
I'm kind of surprised no body went into a seizure or hypnosis with all the strobe lights going off.
When did this happen?
RE: Standard Color for indicator lights
Green is normal, stop or run. If it runs and green, it should be safe for people to work around it. If it stops and green everything is OK and ready to run.
Red is fault or bad, run or stop. It is dangerous condition. If it runs and red, do not cross or stick your hand in. If it stops and red, call the field service guys.
Yellow is warning. Need filter change or low on oils.
Thx,
RE: Standard Color for indicator lights
normally in all power plants which i work G.E &WESTINGHOUSE designs,green colour represent running condition and red is stopping condition,no especial standard is being created for that,but normally green colour is more visable from long distances than red.
RE: Standard Color for indicator lights
The 60's!
RE: Standard Color for indicator lights
RE: Standard Color for indicator lights
http://www.cleanrivers-pdx.org/pdf/16480.pdf
for: 2.9.3 MOTOR CONTROL - PILOT LIGHT
As indicated on the Drawings; provide RED “Motor On” and GREEN “Motor Off, Push-to-Test, transformer-type indicating lights on each starter.
RE: Standard Color for indicator lights
I would not challenge you or your referance, but this is the city of Portland. Is Kansas City the same?
I'm glad that our PLC's can be programed!!! You name it, we do it!
RE: Standard Color for indicator lights
red: machine stopped .with fault
yellow: machine running
green: machine ready for part loading unloading
green/yellow: operator needs to push button to resume cycle
RE: Standard Color for indicator lights
this tells you the colors for pilot lights
RE: Standard Color for indicator lights
:)
RE: Standard Color for indicator lights
RE: Standard Color for indicator lights
RE: Standard Color for indicator lights
RED “Motor On” and GREEN “Motor Off, Ready. AMBER "Alarm"
This is the way I see it done in most industries. Look at pre=packaged accessories for motor starters from all of the major manufacturers. If you want a "Run" light it is red.
Quando Omni Flunkus Moritati
RE: Standard Color for indicator lights
ALTERNATING RED, GREEN, AMBER = "Jackpot!"
BLUE = "Duck and Cover!"
PURPLE = "Hide! The boss is looking for someone to blame!"
WHITE = "Virgin Operator"
MAUVE = "Redecorate"
ULTRAVIOLET = "Jimi Hendrix Alert"
SWIRLING MULTICOLORS = "Flashback to 1969"
Quando Omni Flunkus Moritati
RE: Standard Color for indicator lights
jraef -- In that vein, Lava Lamps never really got their just deserts in industrial annunciation.
RE: Standard Color for indicator lights
We are all so stuck on stodgy practicality that we leave no room for the whimsical in industrial practices.
I vote for the Willy Wonka approach to equipment status indication.
Quando Omni Flunkus Moritati
RE: Standard Color for indicator lights
RE: Standard Color for indicator lights
I submitted your color scheme in the company suggestion box. I even included BUSBAR’s lava lamp as a possible replacement for a strobe light system.
Sure glad I signed the managers name on that one!
RE: Standard Color for indicator lights
jbartos:
I would not challenge you or your referance, but this is the city of Portland. Is Kansas City the same?
///Yes Sir. The AIA specs are pretty much the standard throughout the A/E industry in US and possibly abroad.\\\
I'm glad that our PLC's can be programed!!! You name it, we do it!
///Impressive\\\
RE: Standard Color for indicator lights
GM - Check Engine Light # of Flashes = error code
Allen Bradley - Device-net # of Flashes = error code
Cutler-Hammer - Flashing Run Indicator = Reset network node
All Three examples are the same type of network signal that the maint/operator can see and report back to the control room person on the HIM.
RE: Standard Color for indicator lights
I was feeling left out of agood discussion,so here goes my 3 cents.
Of all the plants I have worked in North America all hi-voltage switchgear used the "RED" for run and "GREEN" for
open.For anything under 750 volts,it seemed that the Standard was no Standard.Some used RED for "Closed" others used GREEN.
GusD
RE: Standard Color for indicator lights
When was the last time anyone saw a green emergency stop button? "
I think this is a great point. How would you have red as the color for emergency stop and for running? What are peoples experiences with equipment that uses red for running? Do they also use red for the emergency stop button?
RE: Standard Color for indicator lights
( NFPA 79 Industrial Machinery)
Color Device Type Typical Function Examples
RED
Pushbutton Emergency Stop, Stop, Off Emergency Stop button, Master Stop button, Stop of one or more motors.
Pilot Light Danger or alarm, abnormal condition requiring immediate attention. Indication that a protective device has stopped the machine, e.g. overload.
Illuminated Pushbutton Machine stalled because of overload, etc. (the color RED for the emergency stop actuator shall not depend on the illumination of its light).
YELLOW (AMBER)
Pushbutton Return, Emergency Return, Intervention - suppress abnormal conditions. Return of machine elements to safe position, override other functions previously selected. Avoid unwanted changes.
Pilot Light Attention, caution/marginal condition. Change or impending change of conditions. Automatic cycle or motors running; some value (pressure, temperature) is approaching its permissable limit. Ground fault indication. Overload that is permitted for a limited time.
Illuminated Pushbutton Attention or caution/Start of an operation intended to avoid dangerous conditions. Some value (pressure, temperature) is approaching its permissable limit; pressing button to override other functions previously selected.
GREEN
Pushbutton Start-On General or machine start; start of cycle or partial sequence
Pilot Light Machine Ready; Safety Indication of safe condition or authorization to proceed. Machine ready for operation with all conditions nornal or cycle complete and machine ready to be restarted.
Illuminated Pushbutton Machine or Unit ready for operation/Start or On Start or On after authorization by lights; start of one or more motors for auxiliary functions; start or energization of machine elements.
BLACK
Pushbutton No specific function assigned Shall be permitted to be used for any function except for buttons with the sole function of Stop or Off; inching or jogging.
WHITE or CLEAR
Pushbutton Any function not covered by thee above. Control or auxiliary function not directly related to the working cycles.
Pilot Light Normal Condition Confirmation Normal pressure, temperature.
Illuminated Pushbutton Confirmation that a circuit has been energized or function or movement of the machine has been started/Start On, or any preselection of a function Energizing of auxiliary function or circuit not related to the working cycle; start or preselection of direction of feed motion or speeds.
BLUE or GRAY
Pushbutton Any function not covered by the above colors
Pilot Light Any function not covered by the above colors
Illuminated Pushbutton Any function not covered by the above colors
RE: Standard Color for indicator lights
RE: Standard Color for indicator lights
Red light: Power on, ready to start, stopped.
Green Light: Power on, started and running at normal condition.
Amber/Yellow light: Overload condition.
All refer to starters of motors.
Alfredo Corona
Mexico
RE: Standard Color for indicator lights
Red should denote danger or a fault condition. I can understand red as a running indicator in that it implies a possible dangerous condition but times have changed. In newer machinery, there should already be adequate guarding/protection to meet OSHA and EU specs. In the past red would be an excellent choice since the equipment was not fully guarded and not as safe to the user in general.
RE: Standard Color for indicator lights
We do really economical (cheap) twin pump float operated panels that use red = running, amber = tripped and higher quality water industry panels that use green = running, amber = tripped or fault and red = dangerous (normally e stop operated)
All applies to the UK
Mike
RE: Standard Color for indicator lights
RE: Standard Color for indicator lights
Doesn't matter what the color of the light is, make sure (with sufficient meter) that the power is off and the circuit safe before working on it.....
RCC
RE: Standard Color for indicator lights
RE: Standard Color for indicator lights
We recently experienced a situation where the designer decided that a certain function would be really usefull if included in the user interface. Any indeed, it's very useful. BUT, he didn't carry it to the logical conclusion, and while if everything is working properly, it's fine, but if something is not working, there is no indication of a problem and the operator can be easily misled for a brief time into thinking that he's exercising the function, when it fact, the function has completely failed.
TTFN
RE: Standard Color for indicator lights
RE: Standard Color for indicator lights
Monitoring this thread, it illiterates to me the need for more standardization. All contributors to this thread have some merit.
Safety should be the main focus however. What I see is a majority opinion that, and I do paraphrase to a degree to support my view.
1.. GREEN: the system START button (illuminated or NOT) indicates system is ready to be started or is running normal, START or GO button once pressed is illuminated Green.
2.. RED: The system STOP button as well as a EPO button if specified. Once pressed the system is OFF. Nothing is illuminated unless the EPO button has been iniated and is illuminated and/or any other alarm status indicator.
3.. RED is also used as an “alarm status indicator” and the red indicator color should only be used to define specific alarm conditions (system running or shut down). These alarm status indications can be; LOW SUCTION PRESSURE, HIGH DISCHARGE PRESSURE, HIGH TEMPERATURE, LOW TEMPERATURE, LOW FLUID LEVEL, etc…You name the condition that you want to use to protect the overall system.
3.. AMBER: All secondary systems are operating normal ie; “HEAT”, “COOL”, BYPASS, HUMIDITY, INJECTION, (you name it); indicating to the operator that the system or sub systems are functioning (cycling on/off or porportionaly) as designed or as required by the system.
Why design a piece of equipment that indicates red (alarm) lights for a normal operating condition? I feel those that do this are giving a confused message of CAUTION and ALARM instead of the true status of the operating equipment, therefore exposing them to possible harm and ourselves to litigation.
Finally, I have to admit, my automatic coffee maker which I set every night so I can have a fresh brew in the morning has red lights to indicate the damn thing is "ON" program mode.
I lie awake at night worrying.
pennpoint
RE: Standard Color for indicator lights
Your last post seems to indicate that you recommend red indicate both "system running or shut down" (from point 3) and that green also be used to indicate system "started or is running normal" (from point 1). Um, I'm still confused.
RE: Standard Color for indicator lights
It is truly amasing how different diciplines can have such entirely different approaches to the same idea based on equipment operation.
RE: Standard Color for indicator lights
BUT, the most useful information that I could possibly want is NEVER display, e.g., can I disconnect it from the computer without losing data?
Someone thought that he provided useful information to the user, when in fact, the one critical piece of information is totally hidden.
Bottom line, it's impossible to use only two colors to indicate the myriad of information you want to display. That's where good signage comes in.
TTFN
RE: Standard Color for indicator lights
Sorry if I continue to confuse you and others. I reread my post and see where someone could be further confused. It was somehow clear to me when I posted. Its the nuance thats lacking here, and without immediate responce and play the subject at hand suffers.
Ill differ to wiser people
pennpoint
RE: Standard Color for indicator lights
RE: Standard Color for indicator lights
Or would it be an amber light?
Quando Omni Flunkus Moritati
RE: Standard Color for indicator lights
RE: Standard Color for indicator lights
RE: Standard Color for indicator lights
ASTM F 1166 section 9.19 has color coding for indicator lights.
I'm looking at a picture of a ship's control console and the only red lights are alarm lights and emergency stop buttons. If there is an illuminated "stop" button (for a pump) or "close" button (for a valve) it is white.
RE: Standard Color for indicator lights
"I love deadlines. I love the whooshing noise they make as they go past." Douglas Adams
RE: Standard Color for indicator lights
http://www.harrob.com/images/Durhamville%20Spec.pdf
for a green light meaning energized
RE: Standard Color for indicator lights
RE: Standard Color for indicator lights
RE: Standard Color for indicator lights
RE: Standard Color for indicator lights
RE: Standard Color for indicator lights
Can't a physical switch be used? However, people would then argue whether it was up/down or left/right.
Why not have the text on the lamp i.e. RUN/STOP/FAIL and then you dont have to worry about colours, just dyslexic operators.
RE: Standard Color for indicator lights
Red-running
Green-available,off,standby
Yellow-disagreement,failed to move or start
White-lockout
Ravenjoe
RE: Standard Color for indicator lights
http://www.pauldavisautomation.com/safetyman.html
for:
There is no specific standard in the U.S. regarding stack lights. However, ANSI under B11.19 section E4.3.2.2.1 states "Due to lamp failure, visual awareness devices should use multiple lamps such as green for run and red for unsafe." What the exact meaning is of those colors on a stack light should be part of the documented operator and maintenance personnel training for that machine.
RE: Standard Color for indicator lights
Back tracking and reading my input over again I find myself in a defensive position here. My point is and has always been GREEN means GO, RED means STOP/WARNING (or an indication why the machine stopped).
The company to which I am employed, design and build verious testing facilities. Not process equipment. These are usually small sized (up to 4000lbs) equipments most are simi-portable. Not paper mills, mill hammers, steel mills, or etc..
My point was and continues to be: Indication of operation should give the operator some since of the degree of safety.
That is to say if you use RED indicator lights to show that the machine and all it's sub-circuits are operating normal you are giving that operator a false warning indication. If you do this, I believe this is old school philosophy.
//It appears most (not all) everyone this thread agrees that RED is STOP/WARNING\\
OSHA has lists of colors to be used as levels of HAZARDS:
Green: Safe
Orange: WARNING
Red: DANGER
Blue: INFORMATIONAL
others:
I use GREEN as a Start button. Red as a STOP button. (normally neither are illuminated). There may be a "HEAT", "COOL", "HUMIDIFY" or more switch(es). Those functions when "ON" would be shown energized with a AMBER indicator. Amber because it can be seen and are not a hazard when functioning or not. They are just to let the operator know that they or working (fuctional/cycled) to the process. You could tell me to use green and I would.
Auto-Shut down; Here, I use RED again only as an indicator to the operator as to: "LOOK" the machine stopped (automatically) approach with caution, find out why. Call your supervisor. The machine can be stopped by "E" stop, temperature, pressure or other harmful limits to its self or to personnel.
In my instance when I say the machine is "OFF" it's off (no auto restart). Only the temperature displays and chart recorder is energized to show the operator where things are or were in the process when it went down.
Cerpico; You yourself elude to the premis Green is GO, RED is stop.
I am saying the samething!!
I guess it comes down to this. If the machine is operating as it is designed, is safe or not. I say yes! and there should be no RED indicator lights lit if all is operating normal. If I approched a machine and pressed the "START" button and the panel lit up RED! I'd run like hell to get out of there. Ya see..
In the "ole" days, (Hey I'm an old guy), I remember the large red bullet nosed indicator panel lights. But these were on open frame, uncaged, unshrouded systems. Workers had to approach these machines with fear in their hearts.
When you start your car there should be no red light showing on the dash, or you'll be calling AAA.
We as a "modern" industrialized nation of standards have come far and away from that. Just because a piece of equipment is "ON" does not mean it's unsafe, nor should we as engineers do what was done fifty years ago.
I see no flaw in this logic, as you seem to do. I do see lack in the communicaton of our thoughts. Maybe your not totally wrong and maybe Iam not totally right, but I think we can meet somewhere in between.
I hope this clears up any confusion from what I have posted in the past. This is my philosophy.
What is obvious here is that there is no real clear standard (now) that we ALL can follow except that we all must try to do the very best we can to address, protect and annunciate the safe operational status to those operators of our individual equipments.
Iam still worried about my coffee maker, is that really a warning light or not?
I wish you all well
pennpoint
RE: Standard Color for indicator lights
Show Joe Average in the street a box with a red button and a green button and ask him which is start and which is stop.
My guess is that most people will go green for go, red for stop.
Same with indicator lamps.
If you are happy that the people who come into contact with the indicator lamp will be educated to know what it means, then fair enough, but if I build a machine here and give it to the workforce then I'd always go for green is go, red is stopped. And I'm a trained electrician so I know that in that trade we use red for on green for isolated...
I though us "engineers" were supposed to be logical!
Alternatively why not throw a spanner in the works and do like Disaster Area's stunt ship:
Zaphod Beeblebrox: "It's weird. Every time I operate one of these weird black controls, that are labelled in black, on a black background, a little black light lights up black to let me know I've done it."
"I love deadlines. I love the whooshing noise they make as they go past." Douglas Adams
RE: Standard Color for indicator lights
RE: Standard Color for indicator lights
RE: Standard Color for indicator lights
I must say, RED as Energised, which is supposed to be the international standard, is very confusing to both myself and the operators.
A stop button is always RED. Not to warn you away from it, but to mean STOP. RED means STOP, no matter what the international standards say. It is convention. It is in our culture, everyone knows it. To try and confuse this is wrong.
For the same reason, Start buttons are Always Green. By the international standar, shouldn't it be RED, to warn you that if you press it it will cause a dangerous situation.
NO, because that would confuse people.
This is why there is no standard that everyone uses. Because the internation standard conflicts with what everybody knows to be "The Right Way" to do it.
In the end, the customer gets what they want, but if it is my choice, I will say stuff the international standard. It is clearly wrong. It is more important to convey a message that everone understands, Not try to make everyone understand a backward standard.
Thats my opinion, and I will stick with it.
RE: Standard Color for indicator lights
RE: Standard Color for indicator lights
red-machine breaker is close m/cis running without any fault
green-m/c breaker is open m/c has no load yet
this is standard practice in hydro power station
RE: Standard Color for indicator lights
For Process control, the process status is best represented by RED=STOPPED & Green = Running.
For Breakers and power distribution status, the status is best represented by RED=LIVE/Energised, GREEN=Dead/De-energised.
The 2 situations are very different.
RE: Standard Color for indicator lights
RE: Standard Color for indicator lights
RE: Standard Color for indicator lights
imply that a system or valve or motor is unsafe. Rather it implys that the greatest potential for error or safety degradation lies within a system that is energized, open, running, etc. This is where the pressure and the flows are in a dynamic state. The greatest potential cause for a traffic accident lies with the person who runs the red light. Each industry seems to have a traditional standard. This is just one industry standard. And change just for the sake of change can be expensive. Human factors is built on experience. There are many bright new engineers entering many industries. Most lack the practical experience that has helped bring human factors engineering to where it is today. Don't attempt to erase that which has evolved over time for a purpose in your particular industry. There are many companies manufacturing in third world countries. And many American standards are being comproimised due to this. There is a reason these countries are "Third world". Why should we in America lower our tested standards for their sakes. Since when does number one slow down in a race just so every one else can catch up? When in Rome..... But when in America then...... Now I am getting condensending again. Geeze all this over a couple of lights!!!
RE: Standard Color for indicator lights
RE: Standard Color for indicator lights
look at a contact block (I have a furnas 64BB and 64BA)
The Green color is on the bottom of a N/O contact and the Red color is on the bottom of a N/C. A&B uses the same color also. Soooo by looking at this I would belive
Red = N/C = RUN or ON - normal position
Green = N/O = Stop or off - normal position
I am no expert only in this field for about 14 yrs.
I belive if you dont learn 1 thing new every day you wasted a day.
If I am wrong in theory please advise
RE: Standard Color for indicator lights
An equally plausible interpretation is that Green for NO is SAFE, while Red for NC is DANGER (perhaps because something is ON)
TTFN
RE: Standard Color for indicator lights
GREEN N/O is used for START buttons which are also green
RED N/C is used for STOP buttons (Fail Safe)which are also red.
RE: Standard Color for indicator lights
If you used the contacts in question as part of a typical two-button motor starter, you would find that the NO (green) is used as the start button, and the NC (red) is used as the stop button. Kinda spoils that theory!
RE: Standard Color for indicator lights
RED..emergency..eg value out of safe limits
Yellow...abnormal...eg value out of normal limits
Green....normal...make a guess
Blue...mandatory....eg instruction for operator to do something
White.....neutral....eg general information
hope this sheds some light
RE: Standard Color for indicator lights
RE: Standard Color for indicator lights
RE: Standard Color for indicator lights
RE: Standard Color for indicator lights
LOL!
I think this thread deserves the longest continuous activity award!
Quando Omni Flunkus Moritati
RE: Standard Color for indicator lights
Green for go
Red for stop
or something similar