When I am thinking power only, I have various devices that are Red, Green, Blue or Yellow and all can indicate that power is flowing (plugged in), or that the device is on. I don’t only associate a specific color with a status, I have to look at the device, and what options are there.
I didn’t see that this was an interlock question.
When looking at making a new device (switch), I would think…
No light is that there is no power
Red is that it has power, but not operational
Green that has power, and can be operated.
I see the SawStop option as specific because the machine has circuitry to detect different states.
Now, if this is a new switch could access some external data to determine current machine abilities…
Yellow could be invoked and flashing yellow to indicate not fully functional, but could be used.
Red could be flashing, and indicate that power is on to the machine, but do not use.
Other than having power, I’m not sure of a use for blue.
And all of this is dependent on the defining data being valid and current. If I get accustomed to a machine being Green light (fully operational), I am building in to the expectation that there are no problems.
As of now, any time I activate a machine, I have to consider that there might be value in testing it to be sure it is trim.