Steinel True Presence Multisensor KNX 056353 flush-mounted presence detector, white

The Steinel True Presence Multisensor KNX (art. 056353) is a white, flush-mounted ceiling presence detector which, besides movement and human presence, also measures brightness, temperature, humidity, air pressure, CO2 and volatile organic compounds (VOC). It works only as a KNX bus device.

Power supply and how it fits into the installation

The sensor is powered from the KNX bus at 30 V and draws 40 mA, about 1 W. The manufacturer states that it must never be connected to 230 V mains — it is intended only for the low-voltage circuits of a KNX installation, and it should be fitted by an installer. The sensor has no relay of its own: it sends its readings and presence status to the bus as objects, and lighting, heating or ventilation are switched by KNX actuators connected to that bus.

It offers four lighting outputs, constant light control, an HVAC output and logic functions. It is configured with ETS software, via Bluetooth or over the bus; no remote control is included. It supports KNX TP, without KNX Secure.

Range and mounting position

The 7.2 GHz high-frequency sensor covers 360°. It detects movement and presence within a circle 15 m across (177 m²), and so-called true presence — the small movements of a person sitting at a desk — within a 9 m circle (64 m²), when mounted no higher than 4 m. The permitted mounting height is 2–12 m, with 2.8 m as the optimum. HF waves can pass through glass, wood and lightweight partition walls, which has to be taken into account when choosing the position.

The plastic housing measures 123 × 123 mm and is 33 mm high, it weighs 0.156 kg, and with IP20 and an operating range of 0–40 °C it is intended for dry interiors. For surface mounting the manufacturer offers a separate adapter.

Where it is used

The manufacturer intends the sensor for classrooms and lecture halls, single and open-plan offices, conference rooms, hotel rooms, care rooms, receptions and sports halls. CO2 measurement across 300–5000 ppm lets ventilation follow the number of people in the room, and a twilight threshold of 2–1000 lx switches the light on only when daylight is not enough.