THEBEN LUNA 121 top3 RC AL Digital Twilight Switch with External Light Sensor, 1-Channel, 1–99,000 lx, 230 V AC, DIN Rail, IP20/IP55

Separating light detection from the control unit gives the LUNA 121 top3 RC AL a decisive advantage over conventional twilight switches. The external surface-mounted sensor can be positioned up to 100 metres away, ensuring daylight is measured exactly where it matters—outdoors, on a pole, or at the point of interest—while the DIN rail module remains protected inside the distribution board. This design, combined with an exceptionally wide 1–99,000 lx range, zero-cross switching, and optional Bluetooth programming, makes it a robust solution for demanding lighting control tasks.

Highlights

• External light sensor with IP55 rating and 100 m cable length for flexible placement
• Extremely wide lux range from 1 to 99,000 lx for fine-tuned switching thresholds
• Zero-cross switching protects relay contacts and extends service life
• Programmable ON/OFF delays prevent false triggering from passing headlights or clouds
• Backlit LCD and intuitive menu for on-device setup; PIN code protection against tampering
• Optional Bluetooth connectivity with OBELISK top3 dongle for app-based programming and copying configurations

In daily use

Installation is straightforward: the 3-module DIN rail unit connects to 230 V AC and the sensor via screw terminals. The sensor, rated IP55, can be surface-mounted on a wall or pole. Once wired, set the desired lux level and any time delays directly on the backlit display. The integrated 24/7 timer allows additional time-based switching, so you can combine dusk-to-dawn operation with scheduled off periods for energy savings.

Full specifications

• Product Type: Digital Twilight Switch
• Sensor Type: External Light Sensor (Surface-mounted)
• Light Sensor Range: 1 - 99000 lx
• Supply Voltage: 230 V AC, 50/60 Hz
• Number of Channels: 1 (Changeover Contact)
• Max. Incandescent/Halogen Load: 2600 W
• Max. LED Load (>2W): 600 W
• Mounting (Switch Unit): DIN Rail (3 Modules)
• Mounting (Light Sensor): Surface-mounted
• Protection Class (Switch Unit): IP20
• Protection Class (Light Sensor): IP55
• Operating Temperature: -30 °C to +55 °C
• Display: Backlit LCD
• Programming Options: Device Buttons, Bluetooth (via optional OBELISK top3 dongle)
• Key Features: Zero-cross switching, Adjustable ON/OFF delay, Test function, 24/7 Timer
• Power Consumption: ~0.8 W
• Connection Type: Screw Terminals
• Max. Sensor Cable Length: 100 m
• Memory: 800 Switching Locations
• Security: PIN Code Protection

Final note

With its remote sensor and precise lux control, the LUNA 121 top3 RC AL is the professional choice for reliable, energy-efficient lighting automation in any environment.