User Manual

Function
s
KNX communications
4
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● Receive timeout: 31 minutes
● Send heartbeat: 15 minutes
Object [KNX obj. Nr.] I/O Minutes Default value
Room operating mode:
Time switch [13]
Receive 31 Comfort
Application mode [48] Receive 31 Auto
Heating/Cooling mode status [46] Receive 31 Heating
Individual zones can also be disabled (out of service) via control parameter if they
are not being used. In disabled zones, the LTE signal no longer sends periodically
and therefore reduces bus load.
4.12.6 Startup
The application is restarted after every reset, so that all the connected motorized
valve actuators are synchronized (see Control outputs [➙ 75]).
After a reset, it takes up to 5 minutes for all the connected room thermostats to
restart. This is designed to avoid overloading the mains power supply when
restarting. At the same time, it reduces the load on the KNX network, as not all
thermostats transmit data at the same time. The delay (T
WaitDevice
) is determined by
the thermostat's device address. The device starts to send after the delay.
4.12.7 Heating and cooling demand
In conjunction with Synco, the heating and/or cooling demand from each room is
transmitted to the BACS to provide the required heating or cooling energy.
An example for LTE-Mode is described in 3.11.4.
In S-Mode, the current state signals of the control outputs are available.
4.12.8 Fault and alarms function on KNX
A fault is sent on the bus in the event of a fault occur (for example, digital fault
input, Dewpoint, communication configuration, and so on.).
An RDG2..KN room thermostat monitors the bus and sends its fault when the fault
has the highest alarm priority. This ensures that the management station does not
miss any alarms.
The alarm with the highest priority is displayed first and sent over the bus if alarms
occur at the same time.
Fault transmission is different in LTE-Mode and S-Mode:
S-Mode LTE-Mode
Fault state
Alarm info (error code + internal
information)
Fault information (internal information)
Alarm text (default text can be edited
with ACS tool)
The table below shows the error code and default alarm texts.
Reducing the bus load
Startup response
Startup delay
Heating output primary
Heating output secondary
Cooling output primary
Cooling output secondary