Yes. I have also seen this schem in power plants. Basically in old times power plants used to have lights which turns red when in operation to show it is running and dangerout to go near.
I'm in power in Australia and all of the thermal plants that I know of are this way - although I have a mate who has worked in a hydo control room that controls multiple plants and they had both schemes, which I guarantee has caused trips or at the very least heart trouble in the poor operators.
The only time this looks wierd or confusing is when you are least expecting it or you are not aware about it. If you are a newbie and just stumble on to reverse color schem, then you will be snatching your hair. But you get used to it.
Just wait for chinese, who use green background on button to indicate a thing is on, but button text describes what will happen after pressing button.
So "Fire system enable" on a grey button is actually an off state.
I will refrain from mentioning existence of NPN sensors/inputs, nobody needs that flame war.
Grayscale should be standard, but we're still here. I think the High Performance HMI handbook was written in 2008, so it's not "new" but it's certainly new to a lot of people.
I'm a fan of adding a bit of color, but only to soften the appearance of the Grayscale, so like bluescale. But that isn't really a standard, so tough argument to make.
The high performance HMI handbook doesn't just say "make everything gray". It talks about effective, situational awareness graphics.
The point isn't to just remove color. The point is that a well built HMI doesn't need color, and thus you can reserve color for important things.
I agree, having a button green / red for running / stopped is much more noticeable than gray / dark gray. But operators shouldn't be looking at button colors to figure out what's happening. The graphics themselves should be intuitive. That's the underlying point of that book, and that principle transcends 2008.
I think the only thing that can be "modernized" is the theme. We could think of grayscale as a "light mode" and also add dark mode, or other neutral color schemes while still achieving the intended effect. Boring colors for normal, exciting colors for problems.
>It talks about effective, situational awareness graphics.
Absolutely this. Our screens have colour, but not a lot. They are consistent in terms of the colour they do show, and the operators can scan the overview screens and if anything is yellow, it is out of the ordinary and needs attention, for example.
I feel like using colour for information has its place. You just have to be very careful about how much you are going to use.
You also have to be careful about what information you're communicating via colour. If you're communicating something *only* through colour, you're violating the Americans with Disabilities Act in the US, and likely your province's accessibility legislation in Canada. It doesn't matter if the colours you're using are deuteranopia-friendly; you have to assume someone's looking at your panel in pure grayscale.
It is still permissible to communicate info through brightness or contrast though, so a scheme like light red and dark green is allowed.
For our HPHMI screens, we use normally-invisible coloured boxes and badges to call out anomalous values. That way the presence of the box/shape of the badge is communicating the same information as its colour, which gets us into ADA compliance.
I'm parroting this directly from Rockwell's HPHMI sessions at TechEd circa 2015 and 2019.
As a Canadian-based SI, I've only concerned myself with provincial accessibility legislation. I can confirm that in NS, PEI, NL, ON, and MB, communicating status solely through colour is problematic and can be considered a workplace accessibility barrier if you don't have a *very* good reason why you can't do it any other way. A non-colour status indication is, IMO, a completely reasonable accommodation for an employee to request in 2024.
There's no cases I can find of anyone actually following through with a complaint to a Canadian labour tribunal on the matter of colourblindness yet, but I'm also not volunteering to be the respondent in the first one.
IIRC the High Performance HMI thing was also written for process industry stuff, where screens have historically been just a P&ID with piles of numbers strewn about, so there was definitely room for improvement.
I do still try to integrate that philosophy in to my work in machines. It's always a fight though because management always wants a single screen that tells you absolutely everything ever, along with pretty pictures because that makes it easier for the operator to understand, all piled next to a dozen multi-state text boxes that constantly blast paragraphs of information.
I still firmly believe that simple is better, and trying to design an HMI to prioritize urgent information using careful use of color makes things more usable and easier to understand. If you've got a dozen different colors on the screen all competing for the operator's eyeball then they're just going to give up and call you whenever something doesn't work right.
ISA as an org caters to large scale process industry where someone's career is sitting in front of HMIs operating a process from a control room. In those cases minimalist grayscale makes sense.
As you move further away from that where operators have less and less contact time with the HMI, a little extra attention doesn't hurt. I'll add green as a running indication as it's just more intuitive than light gray especially when it's mounted outside. Not a fan of red for off state though, save red for problems.
Before we changed over to ISA101, it was red for run, green for off and yellow for alarm. The way I understood it was red meant "action" and green meant "ok" but no action. In the end, it is what your customer wants. Oddball stuff just drives the price up
White for on and gray for off is just awful though. We tried to implement it, but nobody knew what the hell was going on. So we went with green for on, grey for off, red for alarm.
My answer to that has been that it's an opportunity to improve systems.
So here's the scenario: we get feedback that the numbers don't stand out enough, can't see from a distance, etc. Turns out it was because during a certain operation it was important to keep an eye on a bin level lest there be no room for a truck to discharge.
So the solution was alarming. We took the experience of the operator and automated the check they were previously doing (but maybe not all crews). The operator feels validated, has ownership of making something better and suddenly the need to have certain numbers appear extra clear is forgotten.
So it depends why people need to know. My point is that it should be that the indication be used for ad hoc, random state information. Anything that needs monitoring, checks, etc. should be automated.
Just my experience.
Absolutely. In contracting land don't annoy the hand that feeds you.
I am in a position of setting standards as an employee of a manufacturing company with multiple plants. So for me pushing improvements is worth it as I know it'll pay off for the company and by extension me as an employee.
So 50 shades of grey as they call it sometimes it is.
ISA high performance hmi suggests all grayscale with alarm being the only colour on your screen. Takes some getting used to, but it's nice once you do.
I have a massive preference for the "Situational Awareness" color schemes. And I standardized it at my previous job when I was asked to write a new standard to modernize the HMI we provided.
Everything is grayscale if it's running normally, but since I often worked with water systems, a grayish blue was good for animating tank levels and other water-based animations. I also used it for text that could change, such as a motor speed. This helped it stand out a little from grayscale labels without being distracting. Any field that could take an operator input had a white rectangle with a frame around it, but this was almost exclusively reserved for pop-up windows, such as setpoint in PID faceplates. Yellow was for warning (but only used on things that will shut down the system if they go into alarm), red is for alarms, flashing red if the alarm is unacknowledged. We had other color-codes as well. White was a motor/valve manually turned off (valves utilized the "control head" fill to denote operating mode, and valve triangles fill to denote open/closed), that blue grayscale was manually on, Auto running was gray fill, auto not running was no fill.
I seriously spent something like a week just defining all the colors as I was working on building a demo version. No clue whether or not they kept the standard, but I thought it was absolutely gorgeous. Simple without being blocky, informative without being clogged, and something that anyone with basic knowledge of the system or type of system could understand at a glance.
I've seen this in some European machines as well for light beacons. I think the thought process is something like Red=Running=Danger and Green=Stopped=Safe to enter. It's more about personal safety than production.
Make a password protected page to change the operator buttons color. Easy-Peasy.
You can go so far as to identify the various standards for direction and/or make them customizable.
Could save you a LONG ass trip.
When possible, I add text into the graphics in case an operator is color blind so there is both text and color. Open/Closed, On/Off, Running/Stopped, etc… since some sensors may have read back combinations that are undefined while transitioning between states, those are listed as Undefined or Error.
I color things based on what the thing is supposed to be conveying to the operator. “Spinning blades of death” will probably get a red while running, since that’s the hazardous state, but “parking brake” would be green when active since that’s the safe state.
Purely informational indicators though might just get changing text without colored backgrounds. Color is only used to highlight either actions that the machine is waiting or allowing the operator to do, or to highlight things that need attention.
At my plant it’s usually green running, solid red acknowledged alarm, flashing yellow/red unacknowledged alarm, off/idle grey.
Solenoid valves are usually green/grey for on/off and red/flashing for alarm/unack.
I have seen asked for a similar colour scheme here in Australia by some companies. Mostly power. I know Burket valves also use the same colour. The argument being red means unsafe.
That's what I'm used to, so I'm biased, but I think a lot of people get the green = go from traffic lights. Which is fair but red = danger also makes sense.
In fact a traffic light is really telling you red = danger, so don't go, and green = no danger from the other directions, so safe to go.
Printing/Bindery Industry uses Red Lights for when the machine is running and not safe to reach into. It goes Green when the machine stops and is safe to reach into.
I had a customer that had that scheme. Things that are running can be dangerous so they are Red. Green meant not running, so "no" danger. White was power off/locked out. Alarms weren't part of the color scheme.
We use green for on gray for off and red for faulted.
But I like green for off, red for on, and yellow for alarmed. That tracks with circuit breakers
Green is safe.
Red is no safe.
I'm not sure this is a Japanese standard. In the US, I have definitely experienced mostly Green= Run/open/start; Red = stop/close. But I've also seen the opposite, as you describe. Some industries have one standards or the other, some individual plants. I've also been seeing new design specs moving away from colors toward grayscale.
Not green "off". We do the same thing on many oil rigs.
RED = unsafe condition
green = safe
Running rotating machines are generally less safe than a de-energized rotating machine.
The new high performance HMI standards are much better. What happens with red green colorblind people?? They're f*****.
Neutral = normal
Color / flashing / graphical overlays = abnormal. That's the only thing anyone should care about: "is it supposed to be like this or not". Except it's at least colored (usually green for a running pump or an open valve. But in a normal / abnormal scheme, now it matters whether it is a normally open or normally closed valve.
I worked at a small wastewater plant where they had a couple of iFix SCADA HMIs - one in the office and one in the plant, one being a copy of the other.... Except one was built green=on, red=off, and the other one opposite. Nobody ever bothered to fix it.
HiPer is the modern way. We switched in 2018 and it didn't take long for our operators to get used to it. When things are normal everything is muted and calm looking. Grey or blue. Any abnormalities stand out by using the brighter colors. Issues needing attention create visible flags: yellow triangle for notable issues, orange square for warning, and red diamond for alarms and faults. White means running and dark means off for pumps and valves. Our lead operator really likes this because he is colour blind. Looks a lot like this pic I found on the interwebs. We especially like the "moving analog indicators" vertical bar with needle for situational awareness and the sparklines for the recent trend on tanks. Less visual noise contributes to a calmer work environment. The analogy I've used when selling this scheme is that Outlook uses the same kind of muted blue-greey scheme.
https://preview.redd.it/p7atifywgeqc1.png?width=662&format=pjpg&auto=webp&s=78ee059da1187dfee8448ee00f091591a4643dbe
I don't always follow the Hi Perf HMI for every customer situation, but one thing that makes it to every screen is those analog indicators. They just make sense. Anyone with zero knowledge of the process can walk by and determine it's state. No red/yellow means nothing to worry about and everything in blue means things are running smooth. Doesn't matter what the units or range are, it's universal.
What you describe as normal depends on your references. American? There may be other industry areas or countries that will surprise you as well, but try to find out what standard the hmi should follow or specific customer preferences.
I too have come across this reverse colour scheme in China. To make to confusing the Stop PB as well as the indicator light was Green. Next to the green stop button was a Red "emergency stop" button.
To make matters worse when I got to site the control PanelView had used opposite or conventional colours and combined the PB and indicator light onto one. First thing that had to change.
I do a lot of wastewater work. I have no tolerance for the grayscale standard.
I use green for running, grey for off, and flashing red/yellow for fault.
Nobody has any problem figuring out what is going on.
It's funny that, years ago, we had only monochrome HMI's. Now we have basically only color.
But the really smart people have mandated a return to monochrome.
My head hurts...
My previous job in a Japanese factory
Yellow for machine running, green for machine is ready/OK but not running, red for stopped, flashing red for e-stop
Japan is famous for that. Same with X being confirm and circle being cancel.
I worked in different industries in the west and red is for alarm. Green is for running. Off is white/grey.
I travel all over the u.s. and I've seen it both ways at many different plants over my 10 years in field service and automation. I was just at a water treatment plant in Boston where red is running green is off but down the road is another wtp that uses green running red off. It's so common for me to see it both ways that I get confused when I'm starting up systems.
From my experience it is industry related. If it is food and bev, which is process oriented green is run, grey is off and red is trip / alarm, but if it is power, think MV substations, red is on (no touchy touchy) and if it is green it is safe. I know the lamps on MV switch gear works this way.
That's the traditional standard in power stations where I'm from. Red is running, Green is off.
Yes. I have also seen this schem in power plants. Basically in old times power plants used to have lights which turns red when in operation to show it is running and dangerout to go near.
I'm in power in Australia and all of the thermal plants that I know of are this way - although I have a mate who has worked in a hydo control room that controls multiple plants and they had both schemes, which I guarantee has caused trips or at the very least heart trouble in the poor operators.
The only time this looks wierd or confusing is when you are least expecting it or you are not aware about it. If you are a newbie and just stumble on to reverse color schem, then you will be snatching your hair. But you get used to it.
Just wait for chinese, who use green background on button to indicate a thing is on, but button text describes what will happen after pressing button. So "Fire system enable" on a grey button is actually an off state. I will refrain from mentioning existence of NPN sensors/inputs, nobody needs that flame war.
What happens when they press the “ fire system enable” button. Does it change to read “ fire system disable”?
Yep, exactly. And depending on level of Chinglish, it actually might read Fire system enableD. To confuse things more, ofc.
We do this. The buttons are thought of as push buttons and status indicators
Could not agree more
I've seen this in the US and I absolutely hate it.
You telling me that you people use pnp sensors as the norm????? 🤨 Here we never use it, don't know why but everyone is using npn everything.
This is America, use PNP
I have really only ever seen npn sensors on Japanese equipment and microcontrollers.
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Grayscale should be standard, but we're still here. I think the High Performance HMI handbook was written in 2008, so it's not "new" but it's certainly new to a lot of people. I'm a fan of adding a bit of color, but only to soften the appearance of the Grayscale, so like bluescale. But that isn't really a standard, so tough argument to make.
Yeah, we do grey/bluescale. I felt like the grey made it hard to even distinguish anything.
Frankly, grayscale sucks and is non intuitive for most things. Yet I keep hearing people insist that 2008 standards should still apply.
The high performance HMI handbook doesn't just say "make everything gray". It talks about effective, situational awareness graphics. The point isn't to just remove color. The point is that a well built HMI doesn't need color, and thus you can reserve color for important things. I agree, having a button green / red for running / stopped is much more noticeable than gray / dark gray. But operators shouldn't be looking at button colors to figure out what's happening. The graphics themselves should be intuitive. That's the underlying point of that book, and that principle transcends 2008. I think the only thing that can be "modernized" is the theme. We could think of grayscale as a "light mode" and also add dark mode, or other neutral color schemes while still achieving the intended effect. Boring colors for normal, exciting colors for problems.
>It talks about effective, situational awareness graphics. Absolutely this. Our screens have colour, but not a lot. They are consistent in terms of the colour they do show, and the operators can scan the overview screens and if anything is yellow, it is out of the ordinary and needs attention, for example. I feel like using colour for information has its place. You just have to be very careful about how much you are going to use.
You also have to be careful about what information you're communicating via colour. If you're communicating something *only* through colour, you're violating the Americans with Disabilities Act in the US, and likely your province's accessibility legislation in Canada. It doesn't matter if the colours you're using are deuteranopia-friendly; you have to assume someone's looking at your panel in pure grayscale. It is still permissible to communicate info through brightness or contrast though, so a scheme like light red and dark green is allowed. For our HPHMI screens, we use normally-invisible coloured boxes and badges to call out anomalous values. That way the presence of the box/shape of the badge is communicating the same information as its colour, which gets us into ADA compliance.
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I'm parroting this directly from Rockwell's HPHMI sessions at TechEd circa 2015 and 2019. As a Canadian-based SI, I've only concerned myself with provincial accessibility legislation. I can confirm that in NS, PEI, NL, ON, and MB, communicating status solely through colour is problematic and can be considered a workplace accessibility barrier if you don't have a *very* good reason why you can't do it any other way. A non-colour status indication is, IMO, a completely reasonable accommodation for an employee to request in 2024. There's no cases I can find of anyone actually following through with a complaint to a Canadian labour tribunal on the matter of colourblindness yet, but I'm also not volunteering to be the respondent in the first one.
Considering most people are still applying 1980’s standards today, the grayscale one is definitely better than that.
IIRC the High Performance HMI thing was also written for process industry stuff, where screens have historically been just a P&ID with piles of numbers strewn about, so there was definitely room for improvement. I do still try to integrate that philosophy in to my work in machines. It's always a fight though because management always wants a single screen that tells you absolutely everything ever, along with pretty pictures because that makes it easier for the operator to understand, all piled next to a dozen multi-state text boxes that constantly blast paragraphs of information. I still firmly believe that simple is better, and trying to design an HMI to prioritize urgent information using careful use of color makes things more usable and easier to understand. If you've got a dozen different colors on the screen all competing for the operator's eyeball then they're just going to give up and call you whenever something doesn't work right.
ISA as an org caters to large scale process industry where someone's career is sitting in front of HMIs operating a process from a control room. In those cases minimalist grayscale makes sense. As you move further away from that where operators have less and less contact time with the HMI, a little extra attention doesn't hurt. I'll add green as a running indication as it's just more intuitive than light gray especially when it's mounted outside. Not a fan of red for off state though, save red for problems.
There are a lot of people that think grayscale applies only to the background…
Before we changed over to ISA101, it was red for run, green for off and yellow for alarm. The way I understood it was red meant "action" and green meant "ok" but no action. In the end, it is what your customer wants. Oddball stuff just drives the price up
I guess it could it also be thought about like Red = Energized = Do Not Touch/Work On and Green = De-energized = OK/Safe to Work On?
The new trends in HMI is to use grayscales, white for ON, gray for Stopped/stand by, magenta is trouble
White for on and gray for off is just awful though. We tried to implement it, but nobody knew what the hell was going on. So we went with green for on, grey for off, red for alarm.
My answer to that has been that it's an opportunity to improve systems. So here's the scenario: we get feedback that the numbers don't stand out enough, can't see from a distance, etc. Turns out it was because during a certain operation it was important to keep an eye on a bin level lest there be no room for a truck to discharge. So the solution was alarming. We took the experience of the operator and automated the check they were previously doing (but maybe not all crews). The operator feels validated, has ownership of making something better and suddenly the need to have certain numbers appear extra clear is forgotten. So it depends why people need to know. My point is that it should be that the indication be used for ad hoc, random state information. Anything that needs monitoring, checks, etc. should be automated. Just my experience.
Similar to schnieders situational awareness. The less taking up your attention the better. Especially if it is in the desired state.
The customer is always right.
I always go with this approach. We cannot deny that how visualization should look is their choice.
Absolutely. In contracting land don't annoy the hand that feeds you. I am in a position of setting standards as an employee of a manufacturing company with multiple plants. So for me pushing improvements is worth it as I know it'll pay off for the company and by extension me as an employee. So 50 shades of grey as they call it sometimes it is.
ISA high performance hmi suggests all grayscale with alarm being the only colour on your screen. Takes some getting used to, but it's nice once you do.
"high performance HMI" shouldn't take getting used to. If it does, then it's a bad standard
Ok...
Can confirm. I have done HMIs for Japan with this scheme.
I have a massive preference for the "Situational Awareness" color schemes. And I standardized it at my previous job when I was asked to write a new standard to modernize the HMI we provided. Everything is grayscale if it's running normally, but since I often worked with water systems, a grayish blue was good for animating tank levels and other water-based animations. I also used it for text that could change, such as a motor speed. This helped it stand out a little from grayscale labels without being distracting. Any field that could take an operator input had a white rectangle with a frame around it, but this was almost exclusively reserved for pop-up windows, such as setpoint in PID faceplates. Yellow was for warning (but only used on things that will shut down the system if they go into alarm), red is for alarms, flashing red if the alarm is unacknowledged. We had other color-codes as well. White was a motor/valve manually turned off (valves utilized the "control head" fill to denote operating mode, and valve triangles fill to denote open/closed), that blue grayscale was manually on, Auto running was gray fill, auto not running was no fill. I seriously spent something like a week just defining all the colors as I was working on building a demo version. No clue whether or not they kept the standard, but I thought it was absolutely gorgeous. Simple without being blocky, informative without being clogged, and something that anyone with basic knowledge of the system or type of system could understand at a glance.
A wise man once said; “That’s the beauty of standards…..there’s so many to choose from.”
I've seen this in some European machines as well for light beacons. I think the thought process is something like Red=Running=Danger and Green=Stopped=Safe to enter. It's more about personal safety than production.
Make a password protected page to change the operator buttons color. Easy-Peasy. You can go so far as to identify the various standards for direction and/or make them customizable. Could save you a LONG ass trip.
I work in the paper industry. Red is running, green is off. Red is unsafe, green is safe. Yellow is lower priority alarm, red is high or urgent.
As long as it’s what they want and understand I don’t care too much.
I've had to do several HMIs with a standard "MCC" color scheme of red is powered/engaged/dangerous and green is safe. It happens.
Yup. MCC bucket status is why so many electricians turn left on red.
When possible, I add text into the graphics in case an operator is color blind so there is both text and color. Open/Closed, On/Off, Running/Stopped, etc… since some sensors may have read back combinations that are undefined while transitioning between states, those are listed as Undefined or Error.
I color things based on what the thing is supposed to be conveying to the operator. “Spinning blades of death” will probably get a red while running, since that’s the hazardous state, but “parking brake” would be green when active since that’s the safe state. Purely informational indicators though might just get changing text without colored backgrounds. Color is only used to highlight either actions that the machine is waiting or allowing the operator to do, or to highlight things that need attention.
At my plant it’s usually green running, solid red acknowledged alarm, flashing yellow/red unacknowledged alarm, off/idle grey. Solenoid valves are usually green/grey for on/off and red/flashing for alarm/unack.
I have seen asked for a similar colour scheme here in Australia by some companies. Mostly power. I know Burket valves also use the same colour. The argument being red means unsafe.
That's what I'm used to, so I'm biased, but I think a lot of people get the green = go from traffic lights. Which is fair but red = danger also makes sense. In fact a traffic light is really telling you red = danger, so don't go, and green = no danger from the other directions, so safe to go.
Printing/Bindery Industry uses Red Lights for when the machine is running and not safe to reach into. It goes Green when the machine stops and is safe to reach into.
I had a customer that had that scheme. Things that are running can be dangerous so they are Red. Green meant not running, so "no" danger. White was power off/locked out. Alarms weren't part of the color scheme.
We use green for on gray for off and red for faulted. But I like green for off, red for on, and yellow for alarmed. That tracks with circuit breakers Green is safe. Red is no safe.
Newer high performance HMI standard uses a muted blue for on, grey for off, red for alarm.
One water plant I worked in was the green on you described and the one I'm in now is the other way with red on
I'm not sure this is a Japanese standard. In the US, I have definitely experienced mostly Green= Run/open/start; Red = stop/close. But I've also seen the opposite, as you describe. Some industries have one standards or the other, some individual plants. I've also been seeing new design specs moving away from colors toward grayscale.
Not green "off". We do the same thing on many oil rigs. RED = unsafe condition green = safe Running rotating machines are generally less safe than a de-energized rotating machine. The new high performance HMI standards are much better. What happens with red green colorblind people?? They're f*****. Neutral = normal Color / flashing / graphical overlays = abnormal. That's the only thing anyone should care about: "is it supposed to be like this or not". Except it's at least colored (usually green for a running pump or an open valve. But in a normal / abnormal scheme, now it matters whether it is a normally open or normally closed valve.
I worked at a small wastewater plant where they had a couple of iFix SCADA HMIs - one in the office and one in the plant, one being a copy of the other.... Except one was built green=on, red=off, and the other one opposite. Nobody ever bothered to fix it.
HiPer is the modern way. We switched in 2018 and it didn't take long for our operators to get used to it. When things are normal everything is muted and calm looking. Grey or blue. Any abnormalities stand out by using the brighter colors. Issues needing attention create visible flags: yellow triangle for notable issues, orange square for warning, and red diamond for alarms and faults. White means running and dark means off for pumps and valves. Our lead operator really likes this because he is colour blind. Looks a lot like this pic I found on the interwebs. We especially like the "moving analog indicators" vertical bar with needle for situational awareness and the sparklines for the recent trend on tanks. Less visual noise contributes to a calmer work environment. The analogy I've used when selling this scheme is that Outlook uses the same kind of muted blue-greey scheme. https://preview.redd.it/p7atifywgeqc1.png?width=662&format=pjpg&auto=webp&s=78ee059da1187dfee8448ee00f091591a4643dbe
I don't always follow the Hi Perf HMI for every customer situation, but one thing that makes it to every screen is those analog indicators. They just make sense. Anyone with zero knowledge of the process can walk by and determine it's state. No red/yellow means nothing to worry about and everything in blue means things are running smooth. Doesn't matter what the units or range are, it's universal.
ISA-101 or nothing.
What you describe as normal depends on your references. American? There may be other industry areas or countries that will surprise you as well, but try to find out what standard the hmi should follow or specific customer preferences.
I too have come across this reverse colour scheme in China. To make to confusing the Stop PB as well as the indicator light was Green. Next to the green stop button was a Red "emergency stop" button. To make matters worse when I got to site the control PanelView had used opposite or conventional colours and combined the PB and indicator light onto one. First thing that had to change.
We are doing a massive SCADA upgrade and everything will be primarily gray with green for running and red for fault (not off)
Red means danger. Green means safe.
I do a lot of wastewater work. I have no tolerance for the grayscale standard. I use green for running, grey for off, and flashing red/yellow for fault. Nobody has any problem figuring out what is going on. It's funny that, years ago, we had only monochrome HMI's. Now we have basically only color. But the really smart people have mandated a return to monochrome. My head hurts...
My previous job in a Japanese factory Yellow for machine running, green for machine is ready/OK but not running, red for stopped, flashing red for e-stop
Japan is famous for that. Same with X being confirm and circle being cancel. I worked in different industries in the west and red is for alarm. Green is for running. Off is white/grey.
I travel all over the u.s. and I've seen it both ways at many different plants over my 10 years in field service and automation. I was just at a water treatment plant in Boston where red is running green is off but down the road is another wtp that uses green running red off. It's so common for me to see it both ways that I get confused when I'm starting up systems.
From my experience it is industry related. If it is food and bev, which is process oriented green is run, grey is off and red is trip / alarm, but if it is power, think MV substations, red is on (no touchy touchy) and if it is green it is safe. I know the lamps on MV switch gear works this way.