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Siemens
RDG400KN,RGD405KN Basic documentation
CE1P3192en
Building Technologies
2017-02-17
functionality or any other KNX device if the corresponding communication object is
bound.
When engineering with the ETS tool, the time of day can only be displayed on the
RDG400KN when Synco group address 30/3/254 is loaded into the thermostat.
For further details, refer to Basic Documentation [6], "Communication via KNX-bus
for Synco 700", section "Engineering of big systems with ETS".
3.1.2 IAQ control (RDG405KN only)
The IAQ function is used for air quality control on VAV applications. The function is
achieved by controlling the air damper position according to the CO
2
level of the
indoor air as well as the temperature.
Note that the air damper position is also controlled according to the temperature. It
depends on which is higher, the temperature demand or the CO
2
level demand
signal.
The function shall improve the indoor air quality by increasing the volumetric air
flow or
VAV output signal respectively.
∂
If the IAQ value of the room is below the preset CO
2
setpoint, the VAV
output signal is controlled in accordance with minimum flow
∂
If the IAQ value exceeds the CO
2
setpoint, the VAV output signal is
increased slowly until maximum flow is reached
∂
CO
2
control is activated in Comfort mode only.
In Economy and Protection mode, this function is disabled
Vmax is reached, when the IAQ value exceeds the preset CO
2
setpoint plus the
CO
2
proportional band (SP+Xp).
Sp:
CO
2
setpoint [P19]
Xp:
CO
2
proportional
band
[P20]
Vmin: Minimum flow
Vmax: Maximum flow
Parameter
Object
Description
Values
Factory
setting
P19
CO
2
(VOC) setpoint
CO
2
(VOC) setpoint
OFF(0)…5000 ppm 1000
P20
CO
2
(VOC) P-band Xp
Proportional band between
Vmin and Vmax
10…2000 ppm
400
Note
General note
Notes