A-B 855H-BCD24EDR4 Stack Light Module

A-B 855H-BCD24EDR4 Stack Light Module

 

 

The Allen-Bradley 855H-BCD24EDR4 is not a traditional stack light module, but an industrial horn + beacon (audible + visual alarm device) from the 855H signaling series.

Product Information

• Brand: Allen-Bradley (Rockwell Automation)
• Series: 855H Industrial Signaling Devices
• Part Number: 855H-BCD24EDR4
• Type: Horn + Beacon (Audio + Flashing Light Alarm)
• Voltage: 24V DC
• Function: Audible alarm + red strobe warning signal

Electrical / Performance Data

• Supply voltage: 24V DC
• Sound level: up to ~124–126 dB (adjustable tones)
• Light: Red xenon/LED strobe beacon (5 Joule flash type)
• Protection rating: IP66 / NEMA 4X industrial enclosure
• Operating temperature: approx. -25°C to +55°C range

Function (Simple Explanation)

This device combines two warning functions:

• Horn (sound alarm): alerts operators with loud buzzer tones
• Beacon (light alarm): red flashing strobe for visual warning

It is used when machines need urgent status indication or safety alerts.

System Role

It is typically connected to:

• PLC output modules (relay / transistor output)
• Safety PLC / safety relay systems
• Alarm circuits in machines

It does not process signals — it only indicates status.

Typical Applications

• Machine fault alarm systems
• Production line warning signals
• Safety shutdown indication
• Conveyor / packaging alarm systems
• Industrial automation warning towers
• Emergency status signaling

Key Features

• High decibel industrial horn
• Bright red flashing beacon
• Multiple selectable tones (up to dozens of patterns)
• Rugged IP66 / 4X enclosure for harsh environments
• Integrated audible + visual warning in one unit
• Suitable for outdoor and industrial use

Precautions

• Very loud output — avoid close-range installation near operators
• Must use correct 24V DC stable power supply
• Not a stack light segment module (it is a combined horn/beacon unit)
• Ensure proper mounting to avoid vibration damage
• Follow local noise regulations in workplace environments