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  • New item   Modular photo relay | digital twilight switch with daily program | 16 A | 230 V AC | 1–1000 lx | 1CO | IP54 sensor | DIN | VEXEN | DTWR972

    Modular photo relay | digital twilight switch with daily program | 16 A | 230 V AC | 1–1000 lx | 1CO | IP54 sensor | DIN | VEXEN | DTWR972

    Code: DTWR972
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    Price 110.74 € VAT incl.
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    Digital DIN rail twilight switch: external IP54 sensor, illuminated LCD, daily program (Night OFF / Night ON), 1CO 16 A, LED up to 200 W.

  • Product description

    Modular photo relay with external sensor | 16 A | 1–100 lx | VEXEN TWR1

    VEXEN DTWR972 is a digital twilight switch that controls lighting by the real light level and a daily time program. The relay is mounted in the panel on a 35 mm DIN rail (2 modules), while light is measured by an external IP54 sensor installed outdoors. All settings – lux threshold, hysteresis, delay and night switch-off times – are shown on an illuminated LCD and set with buttons.

    Key point:
    A simple photo relay keeps lighting on all night – from dusk to dawn. Many sites do not need that: after business hours or past midnight, shop window, signage or yard lighting only wastes electricity. DTWR972 combines a photo relay and a timer in one device: lighting switches on at dusk, off for the night at a set time, and can switch on again in the morning if it is still dark.
    Sensitivity
    1–1000 lx
    Output
    1CO, 16 A / 250 V AC
    LED load
    up to 200 W
    Program
    daily, 2 memory locations
    Sensor
    external, IP54

    Operating principle

    The external sensor measures ambient illuminance. When light falls below the set threshold, the relay switches the 1CO contact and turns the lighting on; when there is enough light again, the contact returns. Hysteresis (1–200 lx) and delay (from 1 s to 9 min 59 s) prevent chattering caused by car headlights or a passing cloud.

    The daily program works together with the light sensor. Night OFF sets a night-time window during which lighting stays off even though it is dark; when the window ends and it is still dark, lighting switches on again by light level. Night ON is the opposite window, during which lighting is kept on at night. The relay has 2 memory locations.

    The display shows the current light level and settings. A button lets you switch lighting on or off manually or set a permanent ON / OFF mode. The quartz clock changes to summer / winter time automatically, and a CR2032 battery keeps time and settings for about 10 years.

    Why a digital relay?
    On an analogue relay the threshold is set by eye with a knob, whereas DTWR972 shows the lux threshold, hysteresis and delay on the display – the setting can be repeated exactly on another site. Street and yard lighting usually needs 5–20 lx, shop windows and signage 30–80 lx; the 1–1000 lx range covers both cases.

    Technical specifications

    Product type Digital modular twilight switch (photo relay) with daily program and external sensor
    Manufacturer / model VEXEN DTWR972
    Supply voltage 230 V AC, 50–60 Hz
    Power consumption 0.45–1.25 W
    Output 1 × changeover contact (1CO), gap < 3 mm
    Contact material AgSnO2
    Switching current 16 A / 250 V AC (cos φ = 1); 6 A (cos φ = 0.6)
    Min. switching capacity 1000 mW (10 V / 10 mA)
    Max. inrush current 50 A, up to 20 ms
    Incandescent and halogen lamps 2000 W
    Fluorescent lamps uncompensated and series compensated – 1000 W; parallel compensated – 550 W
    Compact fluorescent (CFL) 200 W
    LED 230 V (luminaires > 5 W) 200 W
    Light sensitivity range 1–1000 lx
    Light hysteresis 1–200 lx
    Delay 00:01–09:59 (min:s)
    Time program daily, 2 memory locations
    Functions Lux / Night OFF / Night ON; manual and permanent ON / OFF mode
    Display illuminated LCD
    Clock quartz, ≤ ±0.5 s per day; automatic summer / winter time
    Power reserve approx. 10 years, replaceable CR2032 battery
    Sensor cable up to 50 m (outdoors – H05RR-F or better, indoors – H05VV-F or better)
    Terminals screw, pull-up type
    Protection rating sensor IP54, control unit IP20
    Protection class II (when installed as intended)
    Dimensions 45 × 35 × 58 mm, 2 modules
    Mounting 35 mm DIN rail
    Operating temperature −30…+50 °C (sensor and control unit)
    Weight 0.2 kg

    Main functions

    • Light and time in one device – no separate photo relay and timer needed.
    • Night OFF / Night ON – lighting is switched off for the night and may switch on again in the morning if it is still dark.
    • Precise settings on the display – threshold 1–1000 lx, hysteresis 1–200 lx, delay up to 9 min 59 s.
    • Manual and permanent mode – lighting can be switched on or off by a button without disconnecting the automation.
    • Automatic summer / winter time – no need to reset the program twice a year.
    • 10-year power reserve – time and settings are not lost during a power failure.

    How does it differ from similar models?

    • VEXEN TWR1 – Analogue, 1–100 lx, 1NO, no timer – when switching on at dusk and off at dawn is enough.
    • VEXEN TWR923 – Analogue, 1–10,000 lx, 1NO, no timer – threshold set by knob.
    • VEXEN VSOU-1 – 1CO and a wider 1–50,000 lx range, but no timer – lighting stays on throughout the dark hours.
    • Finder 11.91 – With digital timer and 1CO, LED up to 400 W, but a narrower 2–150 lx range.

    Where is it used?

    • Yard, driveway and car park lighting with night-time switch-off
    • Shop windows and illuminated signs – evening and morning hours only
    • Facade and building outline lighting
    • Site lighting where electricity must be saved at night
    • Floodlights at farms, warehouses and industrial sites
    • Entrance lighting of companies and apartment buildings
    • Replacing a photo relay and timer pair with one device

    Use by need

    For the electrician.
    One device in the panel instead of a photo relay and timer pair – less space, fewer wires and wiring errors, with settings visible on the display.
    For the home or farmstead owner.
    The yard is lit in the evening, the light switches off at night by program and on again in the morning if it is still dark.
    For the company or farm manager.
    Shop windows, signage and the site are lit only when needed – lower costs without extra control.

    Practical use

    A shop sign has so far been switched by a simple photo relay, so it stays lit all night until dawn. Mount DTWR972 in the panel instead of the existing relay and the sensor on the north wall where the sign itself does not light it. Set the threshold to about 30–50 lx and the Night OFF window from 22:00 to 06:00. In the evening the sign switches on at dusk, goes off at 22:00, and on winter mornings after 06:00 lights up again until daybreak. If the sign's LED power exceeds 200 W or the drivers' inrush current is high, the relay controls the coil of a modular contactor.

    Pros

    • Photo relay and daily program in one device
    • Illuminated LCD and precise digital settings
    • Changeover contact 1CO, 16 A
    • Night OFF / Night ON for night-time savings
    • Automatic summer / winter time, 10-year reserve
    • Lamp loads stated by the manufacturer, including LED

    Cons / limitations

    • LED load is limited to 200 W; for a larger LED group or floodlights use a modular contactor
    • Daily program only, with 2 memory locations – no weekly or astronomical program, so different weekday and weekend schedules need another solution
    • Takes 2 modules, whereas analogue relays such as VEXEN TWR1 take 1 module

    ⚠ Safety and installation notes

    • Mount the sensor where daylight reaches it but the controlled luminaires do not – otherwise the relay will start switching itself off.
    • Do not point the sensor south into direct sun or towards the road where car headlights hit it.
    • The control unit is intended for a dry panel (IP20); only the IP54 sensor is installed outdoors. There is no galvanic isolation between the supply and the sensor – route the sensor cable (up to 50 m, outdoors H05RR-F or better) as a 230 V circuit.
    • LED load is limited to 200 W – for a larger LED or floodlight group the relay must control a contactor coil, not the luminaires directly.
    • Protect the circuit with a suitable circuit breaker.
    • Installation must be carried out by a qualified electrician after disconnecting and verifying the absence of voltage.

    Quick selection guide

    1–1000 lx
    1CO 16 A
    LED up to 200 W
    2 DIN modules
    Suitable when you need to:
    • switch lighting on automatically at dusk and off for the night;
    • replace a photo relay and timer with one device;
    • see and set the light threshold precisely on a display.
    Check before use:
    • total LED power (above 200 W – via a contactor);
    • where the sensor will be mounted and how its cable will be routed (up to 50 m);
    • whether there are 2 free modules in the panel.
    Important reminder: the daily program is the same on all days of the week. If lighting must work differently at weekends, choose a weekly timer from the time relay group.
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    FAQ

    How does DTWR972 differ from a simple photo relay?
    In addition to the light sensor it has a daily program: lighting can be switched off for the night at a set time and on again in the morning if it is still dark.
    What do Night OFF and Night ON mean?
    Night OFF is a night-time window during which lighting is off even though it is dark; Night ON is a window during which lighting is kept on at night. Outside the windows the relay switches by light level.
    Where should the sensor be mounted?
    Outdoors, on the north side of the building, where daylight reaches it but not the controlled luminaires or car headlights. Cable up to 50 m.
    How much LED can be connected directly?
    Up to 200 W of LED (luminaires > 5 W). For a larger load use a modular contactor.
    Does the time need resetting in spring and autumn?
    No, the clock changes to summer / winter time automatically, and the battery keeps the settings for about 10 years.
    Can the relay be installed outdoors?
    No, the control unit (IP20) is mounted in a panel on a DIN rail; only the IP54 sensor is installed outdoors.

    Digital photo relay with daily program | 1–1000 lx | 16 A | VEXEN DTWR972

    VEXEN DTWR972 is a digital modular twilight switch with an external IP54 sensor, illuminated LCD and daily program: 1–1000 lx, 1CO 16 A, LED up to 200 W, 2 DIN modules. It switches lighting on at dusk, off for the night and on again in the morning if it is still dark.

    Illustrative image may have been created using AI. The appearance of the product may differ slightly from the image shown. Please refer to the technical specification.

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