Siemens RDG20 KN Series Basic Documentation page 74

4
Functions
Additional functions
IAQ - CO control,
2
KNX objects
control –
IAQ - CO
2
damper signal (P453,
P454, P455, P456, P457,
P458)
74 | 186
IAQ - CO S-Mode objects:
2
●
100 Built-in room air quality values (out)
● 101 External room air quality values (in, for M/S – manager/subordinate
function)
●
102 DC damper demand (1-byte out)
●
103 On/Off damper demand (1-bit in)
concentration is available on the bus via S-Mode object 100 "Built-in room
The CO
2
air quality value". This information can share the CO
an independent fresh air controller.
S-Mode object 102 "DC damper demand" and object 103 "On/Off damper demand"
can share the current damper position to 3rd party equipment.
When the thermostats use M/S - manager/subordinate function, the CO
concentration of the manager can be received from the subordinate device via S-
Mode object 101 "external room air quality value".
IAQ - CO control with DC damper: P453 = 1
2
If DC 0...10 V damper control is selected, the following parameters are available:
●
P453: Indoor air quality damper (1 = DC 0...10 V (U1))
●
P454: IAQ damper proportional band Xp
●
P455: Minimum damper position
●
P457: Maximum damper position
●
P353, P357: Fan min. output
The following graphics show DC damper position during heating/cooling demand
and in the dead zone; the fan is switched on via IAQ demand.
H/C demand
Y
IAQ damper Xp
(P454)
100 %
(P457)
Min
(P455)
W
I A Q
Min Minimum damper position (P455)
W IAQ setpoint (P023)
IAQ
The damper position is based on CO
concentration is higher than the setpoint (P023).
When an independent air ventilation system provides fresh air in the room, the
following setting is relevant:
●
When P458 (fan during IAQ control) = ON, the fan runs during IAQ demand.
●
When P458 = OFF, the fan does not operate during IAQ demand.
For fan coil systems (P458 = ON), in the dead zone (no H/C demand), the damper
does not open, and the fan does not operate until CO
setpoint + ½ P-band.
For universal heating / cooling systems (without fan control), the damper is
controlled by the IAQ demand. Fan remains OFF.
DC damper can be connected directly to thermostat terminal U1 or controlled via
S-Mode object 102: DC damper demand.
concentration in the rooms to
2
Dead zone (P458 = ON)
Y
100 %
(P457)
Min (P455)
Fan_min
IAQ
W
IAQ damper Xp IAQ damper P-band Xp (P454)
Fan_min Min. DC 0...10 V fan speed (P357)
value. The damper is open if CO
2
concentration reaches IAQ
2
2
IAQ damper Xp
(P454)
Fan
= =
IAQ
I AQ
(IAQ)
2
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