The ABB Busch-Watchdog HF KNX IP55 (order family BMH/U2.55.1-88x) is a 360° high-frequency presence detector rated IP55 for damp or outdoor-adjacent ceilings. Choose white matt or black matt below.

5.8 GHz radar penetrates drywall, wood, and glass. Two KNX channels, integrated bus coupler, brightness sensing, constant-light switching, and KNX Data Secure — without the temperature/humidity sensors of the indoor IP20 sister.

Key Features

• IP55 enclosure: Suited to humid rooms, covered outdoor areas, and tough ceilings.
• 5.8 GHz HF radar: 360° detection through non-metallic materials.
• 2 KNX channels: Constant light and brightness-dependent switching.
• Brightness sensor: Threshold-based lighting control (no temp/humidity on this IP55 series).
• KNX Data Secure + ETS .knxprod: Official application under Downloads.
• 2 finishes: White matt (−884) and black matt (−885). Indoor IP20 with climate sensors: BMH/U2.1.1-885.

At a Glance

Specification	Detail
Product type	KNX HF presence detector, 360°, IP55
Order family	BMH/U2.55.1-88x
Technology	5.8 GHz HF radar
Channels	2
Sensors	Brightness
Detection (circular)	Ø max. 10 m @ 2.5 m · 12 m @ 3.0 m · 10 m @ 4.0 m
Protection	IP55
Finishes	White matt · Black matt
Bus system	KNX TP · Data Secure

Product manual, installation instructions, ETS .knxprod, CAD, EPLAN, and CE declaration are under Downloads.

Color / Order Codes

Finish	Order code	Product ID
White matt (RAL 9003 similar)	BMH/U2.55.1-884	2TYZ510505G0601
Black matt (RAL 9005 similar)	BMH/U2.55.1-885	2TYZ510505G0701

Applications

• Bathrooms & utility rooms: Presence lighting with IP55 sealing.
• Covered outdoor ceilings: Carports, balconies, and entrance canopies.
• Partitions & glass: HF detects through materials where PIR fails.
• Indoor climate sensing: Prefer BMH/U2.1.1-885 (IP20 + temp/humidity). Façade PIR: BM/A4.1.

Installation Notes

Recess Ø 68 mm or use PMA surface / box adapters. Connect KNX only (integrated coupler). Import the BMH/U2.55.1 .knxprod from Downloads into ETS and follow the product manual for sensitivity and constant-light setup.