Twilight Switch with Digital Light Sensor 230V 972424

Product Manual

• Digital twilight switch

• DIN-rail mounting 35mm

• Switching capacity 16A

• Adjustable lux threshold 1 – 50,000 Lux

• Twilight switch with Daily, Weekly and Yearly Program

• Permanent switching by date

• Programmable with PC and Smartphone

• Make / Brand: Hugo Muller

• Country of Origin: Germany

The Hugo Muller 972424 is a din rail twilight switch that uses a digital light sensor to turn lighting circuits on and off against measured daylight instead of a fixed clock time. The sensor reads ambient light continuously and the control unit switches when the level crosses the threshold you set, so lighting follows the real sunset and sunrise through every season without needing to be reset.

The digital light sensor reads across a 1 to 50,000 lux range, which covers everything from deep dusk to bright midday sun. An adjustable light hysteresis of 0 to 50 percent stops the output chattering when the level sits right on the threshold, and adjustable delay times filter out short changes such as a passing cloud or a vehicle headlight sweeping across the sensor.

On top of the lux function sit daily, weekly and yearly programs with 60 memory locations, so lighting can be held off during set hours or forced on by date regardless of daylight. The unit programs from a PC or smartphone, which is far faster than setting it on the panel when several units are being commissioned. The sensor unit is IP54 rated for outdoor mounting while the control unit sits at IP20 inside the board, and quartz timekeeping with around ten years of power back up keeps the program intact through supply interruptions.

Key Features

• Digital light sensor with a 1 to 50,000 lux adjustable threshold

• 16A switching capacity on a potential free changeover contact

• Daily, weekly and yearly programs with 60 memory locations

• Permanent switching by date for holidays and seasonal overrides

• Adjustable light hysteresis of 0 to 50 percent prevents output chatter

• Adjustable delay times filter short lived light changes

• Programmable from a PC or smartphone

• High resolution LCD display for on panel setting

• IP54 sensor unit for outdoor mounting

• Around ten years power back up with E2-PROM program security

• 35mm din rail mounting

• Manufactured in Germany by Hugo Muller

Technical data

Model: 972424
Make / Brand: Hugo Muller
Country of Origin: Germany

Common Applications

Street and car park lighting, building facade and signage illumination, compound and perimeter lighting, warehouse yard lights, villa and compound external lighting, shop window displays that should stay off after closing, and any lighting circuit that should follow daylight rather than a fixed clock.

Related Twilight Switches

The 972424 is the digital model in this range, with a programmable light sensor, LCD display and calendar functions. If the job only needs a straightforward dusk to dawn switch with a dial set lux level, the analogue models cost less and take up only 17.5mm of rail. The analog twilight switch 923500 comes with a sensor for wall mounting, and the analog twilight switch 923501 has a sensor for mounting within a housing.

See all options in the digital and analog twilight switches range, or browse digital and analog timers for time based switching where no light sensor is involved.

Why Buy From Qahraba

Qahraba supplies electrical contractors, panel builders and procurement engineers across the UAE and worldwide. Local UAE deliveries are completed within 1 to 2 working days, or collect free from our Dubai store. Call or WhatsApp +971 52 913 9543 for bulk pricing or technical help.

FAQ,s

What is a twilight switch with a digital light sensor?

It is a din rail control that measures ambient light through a sensor and switches a lighting circuit when the level crosses a set threshold. Unlike a timer it follows real daylight, so it adjusts itself as the days get longer or shorter.

What lux range can the 972424 be set to?

The threshold is adjustable from 1 to 50,000 lux, which covers deep dusk through to bright daylight.

Why does it have a light hysteresis setting?

Hysteresis creates a gap between the switch on and switch off levels. Without it, light hovering right on the threshold would make the output flicker on and off repeatedly.

Can it switch LED lighting?

Yes. The rated LED and CFL load at 230V is 400W. Filament and halogen loads are rated up to 2,000W, with lower figures for fluorescent ballasts as listed in the table above.

Does the program survive a power cut?

Yes. Program security is unlimited through E2-PROM, and the power back up runs around ten years depending on the lithium battery life.

Can both the sensor and the control unit go outdoors?

The sensor unit is IP54 rated and designed for outdoor mounting. The control unit is IP20 and must be installed inside a distribution board or enclosure.

How is it programmed?

Either on the unit using the high resolution LCD display, or from a PC or smartphone, which is faster when setting up several units.