With this logic group, roller shutters can be moved into 3 different positions - depending on the intensity of the sun (brightness) - to reduce the heating of the respective rooms. The following applies: The brighter it is, the more the shutters close. The brightness values (lux) are stored in the comparators for positions 1, 2 and 3, i.e. lower and upper. The downstream logics then move the blinds to the specified positions. In addition, the next higher position locks the one(s) below it to prevent the blinds from constantly moving back and forth between the 3 positions in case of strong brightness fluctuations. Thus, once the next higher position is reached, the blind no longer moves back to the position below it. However, the 0-position comparator ensures that the blinds open again when the brightness falls below a defined value, e.g. in the evening or during prolonged cloud cover.
The delayers ensure that the roller shutters only move into the triggered position after a preset time. This prevents the positions from being approached even during short brightness fluctuations.
This automatic system has been working reliably for 2 years. We have set up this logic for 3 façades (south-east, south and south-west). For each of the 3 façades there is a brightness sensor (ABB HS/S 3.1). Each sensor supplies the brightness values for its façade. For the roller shutter actuators (also from ABB), there is a 1-byte communication object Sun: approach height [0..255]. This is controlled by the output of the automatic sun protection. In addition, the 1-bit communication objects >>Activation automatic and sun<< must be activated with a true on the actuator. This can be triggered, for example, by a push button sensor or a scene (leaving the home).
The same group address is also used to activate the automatic sun protection logic group. The second output of the automatic sun protection is used for smaller (not floor-deep) windows. The sun protection Pos.1 is omitted for the roller shutters of these smaller windows.
The advantage of this automatic sun protection system is, among other things, that one saves an additional KNX module for the façade shading. If required, this logic could also be extended with further blind positions and the predefined values for the brightnesses, the delay times and the positions to be approached could be set and easily changed oneself.

Peter Senkpiel (213; 2022.04)