Page 92 - Advanced Course

KNX ADVANCED COURSE

Example of logic applications
Logi kanwendungen -
B i il T dt

M 3/1 4/1 M 3/2 4/2 M 3/3 4/3

1/1 2/1 1/4 2/4 1/7 2/7

1/2 2/2 1/5 2/5 1/8 2/8
Partition A Partition B 0 ... Partition position

1/3 2/3 1/6 2/6 1/9 2/9 1 ... Lighting on/off
2 ... Dim lighting
3 ... Shutter up/down
4 ... Adjust louvres
Room 1 Room 2 Room 3

0/1 0/2

Figure 4: Special logic application

1.4 Open-loop or Closed-loop Brightness Control

A benefit of bus networking is the creation of control loops via the bus using distributed
intelligence. An open-loop or closed-loop lighting control system that has been inserted to
save energy is thus not limited to an individual lamp but can be extended as required if
further actuators are to be included. A distinction is made between closed-loop control
(the controlled variable is measured directly and fed back proportionately) and open-loop
control or control (the controlled variable is specified from a measured variable via a
transmission function).

1.4.1 Closed-loop Brightness Control

Current closed-loop control systems for interior lighting guarantee a constant, adjustable
lighting level (mostly between 200 and 1900 lux) in the workplace. They can if required
also switch off the artificial lighting if the external brightness is sufficient. Constant light
control does not depend on the position of blinds, as it measures and sets the controlled
variable itself.

The method of operation is as follows: The lighting controller that the brightness sensor is
attached to sends telegrams for relative dimming (EIS 2), whereby the step width must be
kept as small as possible. The dimming telegrams are sent cyclically provided that the
setpoint/actual value comparison produces a differential. If the setpoint value reaches +/-
the hysteresis, no more telegrams are sent.

Home and Building Management Systems KNX Association
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