Allen-Bradley 856TC-SNB24Y3Y8Y6Y4 Stack Light

Allen-Bradley 856TC-SNB24Y3Y8Y6Y4 is a 70 mm Control Tower Stack Light designed for industrial signaling on production equipment. This configured stack light from Rockwell Automation delivers four steady LED indicators—Level 1 Green, Level 2 Yellow, Level 3 Blue, and Level 4 Red—at 24 V AC/DC, enabling rapid status recognition across a line. It mounts on a 0.5 in NPT base and features a black housing, aligning with common panel-mount configurations. As part of the 856T Control Tower family, the modular tower supports multi-level signaling up to seven modules and, for this SN-based variant, IO-Link communication is available on supported base types. Rockwell also lists this model as the replacement for the older 855TC-B24Y3Y8Y6Y4 configuration, reflecting ongoing product evolution while maintaining the same signaling scheme. Typical applications include indicating machine status, faults, process progression, or operator alerts on conveyors, packaging lines, and general manufacturing equipment.