Art. No. SC 1000 KNX
Additional information on the window status and the automatic frost protection
The room temperature controller offers various options to change over into the Frost/heat
protection mode. In addition to the switch-over by the corresponding operating mode switch-
over object or by room temperature regulator operation on the device, the frost/heat protection
mode can by activated by a window contact or, alternatively, frost protection can be activated by
an automatic temperature control option. With these options, the window contact or the
automatic function has higher priority. You can use the "frost/heat protection" parameter in the
"room temperature control -> controller general" parameter branch to set the way how such
higher-priority switch-over will take place...
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Frost/heat protection switch-over "via window status"
The 1-bit object, "window status" is enabled. A telegram having the value of = "1" (open
window) and sent to this object will activate the frost/heat protection mode. If this is the
case, the operating mode cannot be deactivated, neither by local operation nor by the
switch-over objects (with the exception of the KNX override object). Only a telegram with
the value of = "0" (closed window) will reset the window status and deactivate the frost/heat
protection mode. After this, the operating mode set before the opening of the window or
that mode carried by the bus while the window was open will be activated.
You can optionally parameterise a window status delay. Such delay can make sense if
short ventilation of the room by opening the window is not supposed to change the
operating mode. You can use the "window status delay" parameter to set this delay time
between 1 and 255 minutes. The window status will only be changed and thus the frost/
heat protection mode activated after this parameterised time has elapsed. A setting of "0"
will effect the immediate activation of the frost/heat protection mode when the window is
open. The window status will be in effect in the heating and in the cooling mode. The value
of the object "window status" is deleted after a reset.
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Frost protection mode switch-over by "automatic frost protection"
For this setting, automatic switch-over to the frost protection mode can be made at times,
depending on the room temperature determined. If there are no window contacts, this
setting can prevent unnecessary heating up of the room when windows or external doors
are open. In connection with this function, a quick temperature drop can be detected by
measuring the actual temperature every minute as, for example, is the case when a
window is open. If the temperature decrease detected reaches a parameterised value the
room temperature regulator will automatically switch over to the frost protection mode. You
can use the "automatic frost protection temperature drop" parameter to set the maximum
temperature drop in K/min for switching over to the frost protection mode. After the time
preset by the "frost protection period in automatic mode" parameter has elapsed, the
regulator will return into the mode which was set before frost protection. Re-triggering will
not be possible.
If a switch-over was made by 1 byte via the KNX change-over object during frost protection
and a new operating mode was received, or a new mode has been specified, this tracked
mode will be set after automatic frost protection. If a switch-over was made by 4 x 1 bit
during frost protection via the change-over object, then this newly received mode will be
discarded after the end of the automatic frost protection. The controller then remains in
frost protection. Only after that can the operating mode be switched over by the objects or
locally on the device. The KNX override object has a higher priority than the automatic frost
protection mode and can interrupt the latter.
i
The automatic frost protection mode only acts on heating for temperatures below the set
value temperature of the operating mode selected. Thus, no automatic switch-over to frost
protection can take place at room temperatures in the dead band or in the active cooling
mode if the "heating and cooling" mode is on. Automatic heat protection activation is not
intended with this parameterization.
i
When a window is open or when the automatic frost protection is active, it is not possible to
switch over the controller operating mode using KNX channels or buttons with the
"operating mode switchover, internal" function, and not in the menu for the settings. An
operation of the KNX channels or buttons will also not be tracked either after the window
closes, or at the end of the automatic frost protection.
Page 188 of 347
Software "Smart Control 501511"
Functional description
