ABB i-bus KNX Product Manual page 43

Once the temperature drops below 20 °C, the system is switched back on again.
6.3 D ead zone
2 2 B
The dead zone is a buffer area between the heating and cooling modes.
Within this dead zone, neither heating or cooling is carried out.
Without this buffer zone, the system would be permanently changing between
heating and cooling. If the set value were to be not reached, the heating would be
activated and the set value would barely be reached before the cooling would start,
the temperature would drop back below the set value and the heating would switch
back on again.
Depending on the type of control, the dead zone may increase by the value of the
h ysteresis .
H U U H
6.3.1 H eating and cooling with continuous control
5 2 B
Cooling set value 24
Heating set value 20
The dead zone (4 K) is not affected.
6.4 B asic set value and current set value
2 3 B
The basic set value is used as the standard temperature for the comfort operating
mode and as a reference temperature for the temperature drop in the standby and
night operating modes.
The parameterised basic set value (see
application ) is stored in object 0 and can be changed at any time via the bus by
U H
sending a new value to
After a reset (bus return), the last basic set value used is restored.
The current set value is the set value actually used for control purposes. It is the
result of all drops or increases due to operating mode control functions.
Example:
With a basic set value of 22°C and a drop in night operation of 4K (for night mode) of
the current set value: 22°C – 4K = 18°C. During the day (in comfort mode), the
current set value is 22°C (if the cooling mode is not active).
The formation of the current set value based on the basic set value can be seen on
the block diagram on the next page:
°C
DEAD ZONE 4 K
°C
o bject 0 (EIS5).
H U U H
b asic set value after downloading the
H U
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