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Siemens
RDG400KN,RGD405KN Basic documentation
CE1P3192en
Building Technologies
2017-02-17
In the case of a typical application, the individual RDU../RDG.. room thermostats –
when used with the RMB795 central control unit – signal their heat demand directly
to the primary controller (in the above example to the RMH760).
(1) and (2) designate the numbers of the distribution zone.
This type of application can analogously be applied to refrigeration distribution
zones.
3.10.5 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 of time, 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. Nr.]
I/O
Minutes
Default value
Room operating mode:
Time switch [12]
Receive
31
Comfort
Room operating mode:
Preselection [7]
Receive
31
Auto
Application mode [31]
Receive
31
Auto
Individual zones can also be disabled (out of service) via control parameter if not
used. In disabled zones, the LTE signal is no longer periodically sent, and will
therefore reduce the bus load.
3.10.6 Startup
The application is restarted after every reset, so that all the connected motorized
valve actuators are synchronized (see "Control outputs", 0).
After a reset, it takes up to 5 minutes for all the connected room thermostats to
restart, thus avoiding network overloads when restarting. At the same time, it
reduces the load on the KNX network, since not all thermostats transmit data at the
same time. The delay (T
WaitDevice
) is determined by the thermostat's device address.
After the delay, the device starts to send.
Explanation relating to
the illustration
Note
LTE-Mode/S-Mode
Reducing the bus load
Startup response
Startup delay
