KNX/EIB bus actuators
Thermal valve actuators
Thermal third party
The RXB2... room controllers also support the use of motorized EIB/KNX bus
actuators. In the tool, select Motoric bus .
• If thermal actuators are selected, Y1 / Y2 are always controlled in parallel to ensure
that several actuators can be connected at the same time.
• It is not possible to ensure exact parallel running of more than one thermal valve
actuator. If several radiators are controlled by the same room controller, preference
should be given to motorized actuators.
If thermal actuators must nevertheless be controlled in parallel, third-party thermal
must be parameterized regardless of manufacture. This applies also if an external
power amplifier is used to drive the actuators.
• Thermal actuators operate at a raised temperature. To ensure a fast response, the
actuators are continuously preheated to a slightly higher temperature (5% – 1 s ON /
19 s OFF). They therefore continue to receive pulses from the controller even when
Möhlenhoff actuators have been tested successfully in our HVAC laboratory.
Electromechanic third-party devices often have different runtimes for opening and
closure. For optimal control, the longer of the two runtimes must thus be parameterized.
When switching on the controller, after parameterization, after switching from test mode
to normal mode and for valve protection (unblocking, see page 84), the actuators are
• Thermal heating and cooling valve actuators are controlled for 5 minutes with open
(50% – 1 s ON/ 1 s OFF), then for 5 minutes with close" (5% – 1 s ON/ 19 s OFF).
• Motorized actuators are opened first (110% runtime) and then closed (110%
The sequence starts after synchronization.
The actuator type used must be defined at the engineering stage:
Select Edit parameters, Sequences :
RXB (KNX) Applications library
CLC and RAD description of functions for CC-02 CM110384en_03
28 Feb 2009