The table shows how the properties of a microwave sensor differ from those of a normal PIR (Passive Infra-Red) sensor. A microwave sensor can detect movement on the other side of a thin wall, such as one made of plaster. This function is particularly beneficial in areas such as WC’s, where the light can be switched on prior to the door being opened. The sensitivity (or the detection range), however, can be reduced to avoid erroneous detection.
A microwave sensor should not be placed close to ventilation outlets or large metal surfaces as this may cause the sensor to detect movement constantly. The settings for sensitivity, time after last movement and lux threshold are adjusted in fixed steps on the sensor module. The relay output can be loaded differently, depending on whether you are switching on/off one or more luminaires, or using the relay to adjust the lighting between various levels, referred to as absence dimming or corridor function.
How does a microwave sensor work?
Like a radar, the sensor sends out a signal with a power rating of less than 10 mW, which is then reflected back. When the time of the reflected signal changes, the sensor detects a movement. The power of a sensor is around a hundredth of that emitted by a mobile phone.
e-Sense Detect on/off
e-Sense Detect absence dampening
e-Sense Detect is suitable for:
- Copying and storage rooms, toilets, corridors, cloakrooms and stairwells.
Along with the Tridonics HF-ballast, the relay in the microwave sensor can be used for a corridor function. Instead of disconnecting the power to the HF-ballast, a control cable is connected to the relay output of the sensor, thus regulating the light. The relay is closed by someone’s presence and provides full lighting immediately. After the last detected presence and the expiry of the delay, the light is slowly adjusted down to 10 %.
Certain luminaires with sensors and connections for corridor function can only be used at 75 % sensitivity due to interference between the frequency of the fluorescent lamps and the sensor. The master luminaire and slave luminaires are connected with 4-core. The HF-ballast is the Tridonic Excel One4all or the ECO-lp T5 (for compact fluorescent lamps, only the One4all is suitable). In special cases, the One4all ballast can also be programmed for other functions.