UP 255D21 KNX Brightness Sensor with Constant Light Level Controller 5WG1255-2DB21

Product Summary
UP 255D21 KNX Brightness Sensor with Constant Light Level Controller 5WG1255-2DB21 Product Overview This KNX ceiling brightness sensor delivers precise mixed light measurement with an integrated constant light level controller for automatic daylight-harvesting dimming — no separate controller needed...
Basic Properties
Place of Origin: EU
Certification: CE RoHS
Model Number: 5WG1255-2DB21
Trading Properties
Minimum Order Quantity: 5
Payment Terms: T/T,Western Union
Product Description
UP 255D21 KNX Brightness Sensor with Constant Light Level Controller 5WG1255-2DB21
Product Overview

This KNX ceiling brightness sensor delivers precise mixed light measurement with an integrated constant light level controller for automatic daylight-harvesting dimming — no separate controller needed. Mounted compactly, it measures ambient illuminance while driving one main luminaire group plus up to four additional groups at a user-defined lux setpoint. Daylight increases cause proportional dimming; decreases cause ramp-up — saving energy with visual comfort. Self-calibration ensures accuracy. IR decoder supports S 255/11 remote.

Technical Specifications
Protocol KNX TP, S-Mode ETS; mixed daylight + artificial light measurement
Mounting Ceiling flush box min. Ø60 mm x 40 mm depth; surface adapter optional
Constant Light Controller Integrated — main group + up to 4 additional groups
Control Mode Fully automatic with self-calibration included
Switching Output Integrated 2-point control (switching function)
Lux Setpoint Configurable per group; different zone targets
Calibration Automatic; no recalibration needed
IR Decoder Integrated for S 255/11 remote
Programming Button Front-accessible
Power Supply Integrated bus coupler; DC 21–29 V KNX bus; no external power
Dimensions & Certification 88x63x88 mm; IP20; Data sheet A6V10489482; Warranty 24 Months
Applications

Offices with window walls, classrooms, open-plan workspaces, retail stores with glazed fronts, galleries where lighting must respond to daylight conditions. Pairs with KNX dimming actuators; 2-point output for non-dimmable on/off. Values broadcast for HVAC compensation or shading control.

Product Details
Features: KNX Bus-powered Operation
Channel Configuration: 16 Independent Control Channels
Timer Function: Supports Scheduling And Timer Settings
Installation Type: Wall-mounted Or Embedded
Input Type: Binary Input
Humidityrange: 10% To 90% Non-condensing
Channel: 12 Independent Channels

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