Colors of indicator light
Indicator lights include a colored lens such as red, green, blue, yellow, clear, or white. These colored lenses symbolize the condition of the machine or equipment to which the lights are connected.
The meanings of the different colored indicators are listed below.
- Red means emergency (Hazardous and condition): Immediate action to deal with hazardous condition (e.g., by operating the emergency-stop)
- Yellow means abnormal (Abnormal condition or impending critical condition): Monitoring or intervention (e.g by reestablishing the intended function)
- Green means normal (Normal condition): Optional
- Blue means mandatory (Indication of a condition that requires action by the operator): Mandatory action
- White means no specific meaning (Other conditions can be used whenever doubt exists about the application of other colors): Monitoring.
(All five of these colors are available for sale in automation online store.)
Brightness is measured in lumens, while the energy a bulb consumes is measured in watts. To produce similar amounts of light, LED and fluorescents bulbs consume far fewer watts than incandescent or halogen bulbs. A standard 60W incandescent produces 800 lumens, whereas LEDs consume 13-15 watts to produce 800 lumens.
LED are used in indicator lights due to the following reasons:
- LEDs are used when the heat generated by incandescent lamps would damage nearby equipment or interfere with a precision process. This is particularly advantageous when multiple lights are grouped.
- LEDs can operate at low temperatures which would cause incandescent lamps to fail since glass cracks during rapid cooling.
- LEDs consume 50 times less power than incandescent lamps, thereby reducing energy consumption.
- LEDs last 500 times longer than incandescent lamps. LEDs average a million hours (114 years) while incandescent lamps average 2000 hours.
- LEDs do not generally "blow out" unless subjected to a severe overvoltage. They exhibit a half-life type diminishment in brightness over time.
- After 50000 hours (6 years) of use, LEDs will retain approximately half of their original intensity.
- LEDs have high visibility.
- LEDs require little or no maintenance because of their long life and high reliability.