Light Towers

[chantecler]

Hi all,

I have a question about light towers, the way I have always used them and the way I was taught is like indicator lights, i.e. Green means ok, on, working, running, etc. Red means not ok, stopped, emergency, etc. But I have also seen light towers used like a traffic light, i.e. Green means you can safely enter, introduce your hands, etc, while Red means do not pass, machine is working be careful, do not touch, etc.
Is there any standard about this subject?

Thank you.

 

[jstolaruk]

In my experience, its always customer or plant driven and definitions range all over the place.

 

[Plantationpark]

We tend to reference IEC60073:
Red - Danger
Amber - Warning
Green - Safe
- though if a company has a specific internal standard, its probably better to ensure there is concistancy accross a site...

 

[I_Automation]

A customer of mine has a processing line from Taiwan that when running normally the green light is on, the yellow light is either on or flashing with no indication of why it starts flashing and the red light flashes about 75% of the time (with yellow and green on) - also without any notice, warning or alarm on the HMI.

Another customer red means the operator wants his foreman, yellow they want maintenance and green they need a hilo. Some of their machines have blue which means they want a quality control person, or an operator on a nearby machine wants one.

EDIT: Machines from Germany with the schematic and PLC descriptions in German a translation of their word becomes "Traffic Light"

 

[chantecler]

Thanks for the replies, I'm thinking that it is more like a local standard than a global standard and that consistency across the plant (or plants) is important. I'm going to look for the IEC60073 norm too.
Greetings to the Detroit guys. I will never forget my time in Ann Arbor.

 

[joseph_e2]

I'd say it's generally a plant-level standard. What I've almost always seen across several facilities (all automotive manufacturing):
Green: Machine is running in auto (flashing if it's in run-out/emptying cycle)
Red: Machine has a fault (flashing if it's a "new" alarm)
Yellow: Machine has a warning
Blue: Machine needs material (flashing when low, solid when out) or is in "demand hold" because there's no room to put its finished parts at the next machine.

I've also seen an area light that's green when the magazine can be removed and red when the elevator is raised and it can't be removed.
And other stack lights that indicate different needs (material handler, material, supervisor, etc.).

 

[01101]

Definitely plant level, the food plants that I have worked at used,
Green solid: Running Ok
Green Flashing: Ready to Start
Yellow: warning / over temperature of oven
Red: Alarm / Fault
Blue: Safety contactors energized.

 

[chantecler]

I see. Thank you all.

 

[NetNathan]

Depend on light tower functions.
We use them on our furnaces.
White - Auto Cycle active
Amber - Pumping active (vacuum furnace)
Red - Heating active
Blue - Cooling active
Green- Unload condition