Siemens RDG20 KN Series Basic Documentation page 60

Functions
4
Additional functions
Note
Dehumidification
Note
Humidification
Humidification
HumDehumMode
Max. shift temperature
setpoint (P461)
P461 > 0 K
60 | 180
The maximum temperature shift setpoint value is reached at setpoint humidity high
(P024) +10%. The contact for the dehumidifier is released at setpoint humidity
+15%.
Applications with a DC 0...10 V fan:
●
Enable the function to control the external dehumidifier directly via relay output
by setting P400 (output Q1), P401 (output Q2) or P402 (output Q3) to 7.
When the output is energized, S-Mode object dehumidification sends the
information "ON" to the bus
●
The selected relay output is switched on if relative humidity exceeds the high
setpoint by +15%.
●
For applications with On/Off valves on Q1 or Q2 or both, the output Q3
(P402 = 7) is used to control the external dehumidifier.
●
The relay contact remains closed or open for the minimum On/Off time defined
by P212 or P213.
Applications with a 3-speed fan:
●
The external dehumidifier is controlled via external DC – On/Off converter
connected to analog output Y50. The output signal is DC 10 V if
dehumidification control is requested.
●
Output Y50 remains On for min. 30 seconds (not selectable).
●
This function is available without specific settings (P400, P401 and P402 are
not displayed).
The current of the external DC – On/Off converter cannot exceed the maximum
output current of Y50 (max. 5 mA). We recommend using the converter from Titan
(single relay control (IO/1RM) at 3 mA input current).
The function controls minimum relative humidity in the room and is available only
for applications with DC 0...10 V fan or no fan.
The external humidifier connected to the relay output is enabled as soon as
humidity drops below setpoint humidity low (P026) at hysteresis is ± 5 %.
To enable the relay function, set P400 (output Q1), P401 (output Q2) or P402
(output Q3) to 8. The humidification S-Mode object sends On to the bus as soon as
the output is energized.
When humidity drops below the low setpoint or exceeds the high setpoint, symbol
is displayed and S-Mode object HumDehumMode sends the corresponding
state on the bus.
When humidity reaches setpoint humidity high (P024), the thermostat shifts the
temperature setpoint to reduce relative humidity in the room.
The maximum shifting temperature setpoint can be set via P461 at Expert level at
a setting range of -3...3 K, depending on the connected equipment. The factory
setting is 3 K.
The maximum shifting temperature setpoint value is reached at setpoint humidity
high (P024) +10%.
The positive values of P461 (0.5...3.0 K) are used for heating and cooling, or
heating in a humid cold environment.
For heating and cooling, both temperature setpoints (heating and cooling) are
shifted in parallel (i.e., dead zone remains unchanged).
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