Office Building Solution

BU I LDI NG SOLUT IONS

29

— Architecture and configuration of a KNX system

— Coupler (line, field, repeater)

For a bus line equipped with a power supply, a maximum limit of 64 connectable devices is normally considered, taking into account the total power consumption of the devices and the maximum current that can be supplied by the power supply. However, up to 256 bus devices can theoretically be connected on each KNX line if the line is structured in four segments, each equipped with its own power supply and connected to each other by repeaters. The repeater is a special way of using a system device called a “coupler” which galvanically separates the bus lines, regenerates the signal, prevents an electrical fault in one line from propagating to the other lines and also allows the overall architecture of a KNX system to be extended up to a maximum limit of 65,536 devices.

Maximum extension of a KNX line

LC

Line segments

LC

DISP

PS DISP DISP

DISP

PS

LC

DISP

DISP

DISP

PS DISP DISP

DISP

The coupler device can therefore be used in several ways:

64

DISP

LC

• area/area coupler: it connects areas together along the main backbone (backbone line) • 2 line/area coupler: connects the lines in an area along the main line (main line) • 3 repeater: connects two line segments together, regenerating the signal that could be degraded. • 4 telegram filter: the coupler device can be set to block the passage of certain telegrams, thus preventing them from being sent unnecessarily throughout the network; this would in fact limit the communication capacity and increase the probability of errors and collisions between packets.

DISP

PS DISP DISP

DISP

DISP

64

DISP

LC

Power supply

PS

Device

Coupler/Repeater

The couplers must be addressed like any other KNX device, and can be configured with the ETS software.

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