Stack lights and machine lights are used for alarm and machine status indication. They can be supplied with audible alarms and be used as flashers or steady light configurations. The number of lights in a stack can range from one to six, but sometimes even greater than six lights can be supplied. Lighting options for stack lights and machine lights include lamps that are continuously on and lamps that flash at intervals. Mounting options available include pole mount, direct or base mount and wall mount.
Important electrical parameters to consider when specifying stack lights and machine lights include DC voltage rating, AC voltage rating, power rating, and flashing rate. The DC voltage rating is the maximum DC voltage rating for the light. Similarly, the AC voltage rating is the rated AC voltage for the light. The power rating is the maximum power rating of the light. For stack lights and machine lights the flashing rate is the rate at which the product flashes. Note, however, that this is not applicable for continuous lights.
Stack lights and machine lights may come with safety approval ratings. The maximum current or voltage rating for a product given by an approval organization may be different than the supplier’s designed maximums. In some cases, the product may be used safely at an unapproved level. Check with the supplier, however, for specific usage details. Features common to stack lights and machine lights include audible alarms, manual operations and outdoors usage.
Stack lights and machine lights can be supplied in a variety of colors. There is no specific standard in the U.S. regarding stack light colors. However, ANSI under B11.19 section E220.127.116.11.1 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. Colors commonly available for stack lights and machine lights include amber or orange, blue, clear, green, red, and yellow.