
Functions
KNX communications
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4.12.5 Send heartbeat and receive timeout
In a KNX network, S-Mode and LTE-Mode communication objects can be
exchanged between individual devices. The "Receive timeout "defines the period of
time within which all the communication objects requested from a device is
received at least once. If a communication object is not received within this period,
a predefined value is used.
Similarly, the "Send heartbeat" defines the period of time within which all the
communication objects requested must be transmitted at least once.
Fixed times are specified as follows:
●
Receive timeout: 31 minutes
●
Send heartbeat: 15 minutes
Object [KNX obj. no.]
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 [
78]).
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
Together 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.
LTE-Mode/S-Mode
Reducing the bus load
Startup response
Startup delay
Heating output primary
Heating output secondary
Cooling output primary
Cooling output secondary