Page 128 - Basic Course

KNX BASIC COURSE

The following applies:
There may only be one group speaker for each group address. The setting is carried
out via the ACK flag for one of the group objects that is linked with the group address.
The group speaker flag shall be set at the actuator which is furthest away.
If a repeater is retrofitted, the following must be carried out:
 Integrate the repeater in the ETS project:
The new repeater status is automatically set for all the PL 110 devices in the
project.
 Download repeater status:
All the devices must be informed about the new repeater status by downloading
the application software. Only once the download is concluded are all the devices
aware that a system coupler with repeater function has been integrated into the
installation.
 The mains couplers are now aware of the existence of a system coupler in the
installation.
 A transmitting mains coupler will now no longer repeat the telegram, should the
reply telegram not be sent.

The system coupler must be installed in a central point of the installation (in the
distribution board).
Only one system coupler per installation is permitted. If a larger KNX/EIB installation is
implemented, in which there are several KNX Powerline areas, a system coupler with
its own System ID must be installed in each KNX Powerline area.

3.5 Bus Access Procedure

As in KNX-TP, a bus access procedure is also necessary for KNX PL 110 in order to
prevent collisions.
Owing to the high level of background noise on the 230/400 V supply system, bus access
cannot be related to the voltage level.
The collision problem has been resolved by the use of special time slots i.e. every mains
coupler may only transmit during specified periods. However, if several mains couplers try
to start transmission simultaneously, the following applies:
The mains couplers detect a collision and determine a new random priority for the
transmission of telegrams.

Home and Building Management Systems KNX Association
KNX Powerline PL 110 Powerline_E0814a 10/17